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|Publication number
|Publication type
|Application number
|Publication date
|Aug 25, 2009
|Filing date
|Jun 5, 2006
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|Jun 5, 2006
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|Stephen Forrest, Hiroshi Kanno
|Original Assignee
|The Trustees Of Princeton University
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|Patent Citations (62), Non-Patent Citations (34), Referenced by (5), Classifications (14), Legal Events (5)
|External Links: USPTO, USPTO Assignment, Espacenet
This invention was made with Government support under Contract No. DE-FC26-04NT42272 awarded by the Department of Energy. The government has certain rights in this invention.
The claimed invention was made by, on behalf of, and/or in connection with one or more of the following parties to a joint university corporation research agreement: Princeton University, The University of Southern California, and the Universal Display Corporation. The agreement was in effect on and before the date the claimed invention was made, and the claimed invention was made as a result of activities undertaken within the scope of the agreement.
The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters. In preferred embodiments, the invention relates to white-emitting OLEDS (WOLEDs).
Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting devices, organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants.
As used herein, the term "organic" includes polymeric materials as well as small molecule organic materials that may be used to fabricate organic opto-electronic devices. "Small molecule" refers to any organic material that is not a polymer, and "small molecules" may actually be quite large. Small molecules may include repeat units in some circumstances. For example, using a long chain alkyl group as a substituent does not remove a molecule from the "small molecule" class. Small molecules may also be incorporated into polymers, for example as a pendent group on a polymer backbone or as a part of the backbone. Small molecules may also serve as the core moiety of a dendrimer, which consists of a series of chemical shells built on the core moiety. The core moiety of a dendrimer may be a fluorescent or phosphorescent small molecule emitter. A dendrimer may be a "small molecule," and it is believed that all dendrimers currently used in the field of OLEDs are small molecules. In general, a small molecule has a well-defined chemical formula with a single molecular weight, whereas a polymer has a chemical formula and a molecular weight that may vary from molecule to molecule. As used herein, "organic" includes metal complexes of hydrocarbyl and heteroatom-substituted hydrocarbyl ligands.
OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting. Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.
OLED devices are generally (but not always) intended to emit light through at least one of the electrodes, and one or more transparent electrodes may be useful in an organic opto-electronic devices. For example, a transparent electrode material, such as indium tin oxide (ITO), may be used as the bottom electrode. A transparent top electrode, such as disclosed in U.S. Pat. Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entireties, may also be used. For a device intended to emit light only through the bottom electrode, the top electrode does not need to be transparent, and may be comprised of a thick and reflective metal layer having a high electrical conductivity. Similarly, for a device intended to emit light only through the top electrode, the bottom electrode may be opaque and/or reflective. Where an electrode does not need to be transparent, using a thicker layer may provide better conductivity, and using a reflective electrode may increase the amount of light emitted through the other electrode, by reflecting light back towards the transparent electrode. Fully transparent devices may also be fabricated, where both electrodes are transparent. Side emitting OLEDs may also be fabricated, and one or both electrodes may be opaque or reflective in such devices.
As used herein, "top" means furthest away from the substrate, while "bottom" means closest to the substrate. For example, for a device having two electrodes, the bottom electrode is the electrode closest to the substrate, and is generally the first electrode fabricated. The bottom electrode has two surfaces, a bottom surface closest to the substrate, and a top surface further away from the substrate. Where a first layer is described as "disposed over" a second layer, the first layer is disposed further away from substrate. There may be other layers between the first and second layer, unless it is specified that the first layer is "in physical contact with" the second layer. For example, a cathode may be described as "disposed over" an anode, even though there are various organic layers in between.
As used herein, "solution processible" means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.
As used herein, and as would be generally understood by one skilled in the art, a first "Highest Occupied Molecular Orbital" (HOMO) or "Lowest Unoccupied Molecular Orbital" (LUMO) energy level is "greater than" or "higher than" a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Since ionization potentials (IP) are measured as a negative energy relative to a vacuum level, a higher HOMO energy level corresponds to an IP having a smaller absolute value (an IP that is less negative). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) having a smaller absolute value (an EA that is less negative). On a conventional energy level diagram, with the vacuum level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A "higher" HOMO or LUMO energy level appears closer to the top of such a diagram than a "lower" HOMO or LUMO energy level.
White organic light-emitting devices (WOLEDs) have gained interest because they can be used for various applications including flat panel displays and lighting sources. The quality of white illumination sources can be fully described by a simple set of parameters. The color of the light source is given by its CIE chromaticity coordinates x and y (1931 2-degree standard observer CIE chromaticity). The CIE coordinates are typically represented on a two dimensional plot. Monochromatic colors fall on the perimeter of the horseshoe shaped curve starting with blue in the lower left, running through the colors of the spectrum in a clockwise direction to red in the lower right. The CIE coordinates of a light source of given energy and spectral shape will fall within the area of the curve. Summing light at all wavelengths uniformly gives the white or neutral point, found at the center of the diagram (CIE x,y-coordinates, 0.33, 0.33). Mixing light from two or more sources gives light whose color is represented by the intensity weighted average of the CIE coordinates of the independent sources. Thus, mixing light from two or more sources can be used to generate white light.
When considering the use of these white light sources for illumination, the CIE color rendering index (CRI) may be considered in addition to the CIE coordinates of the source. The CRI gives an indication of how well the light source will render colors of objects it illuminates. A perfect match of a given source to the standard illuminant gives a CRI of 100. Though a CRI value of at least 70 may be acceptable for certain applications, a preferred white light source may have a CRI of about 80 or higher.
White OLEDs having only phosphorescent emissive materials may be highly efficient, but their operation stability is currently limited by the lifetime of the blue phosphorescent component. White OLEDs having all fluorescent emissive materials may have good operational stability, but their external quantum efficiency is generally about three times lower than that of all-phosphorescent white OLEDs. The present invention combines phosphorescent and fluorescent technologies in an improved device structure to achieve an improved balance of efficiency and lifetime in a white OLED.
The present invention provides a combination fluorescent and phosphor-sensitized-fluorescent white organic light-emitting device (WOLED), employing a conductive host material doped with a phosphorescent green, and the fluorescent red and blue emitters. Although two fluorescent dopants are employed along with only a single phosphorescent dopant, the device of the invention can, in principle, achieve 100% internal quantum efficiency.
The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters.
The present invention provides an organic light emitting device comprising a cathode, an emissive region, and an anode. The emissive region comprises a fluorescent layer comprising a first fluorescent emitting material as a dopant in a host material, and a phosphorescent-sensitized fluorescent layer comprising a second fluorescent emitting material and a phosphorescent emitting material as dopants in a host material. In certain embodiments the fluorescent layer and the phosphor-sensitized layer are separated by a spacer layer.
The present invention also provides an organic light emitting device comprising a cathode, an emissive region and an anode, in which the emissive region has the following layers in sequence:
Fluorescent organic light-emitting devices have an upper limit of approximately 25% for internal quantum efficiency (IQE), due to the requirement of spin-symmetry conservation. The alternative radiative process of phosphorescence has shown very high, even nearly 100% IQE. However, blue phosphorescent dopants with long lifetimes have not been achieved yet, which limits the device lifetime and thus the application potential of the three-color white OLED (WOLED) using red, green and blue phosphorescent dopants. Furthermore, in devices having only phosphorescent emitting materials, the exchange interaction energy is effectively lost, since phosphorescent materials emit light from spin-symmetric excitons (triplets) whose energy level is ˜0.8 eV lower than spin-antisymmetric excitons (singlets) in organic system. In the present invention, these deficiencies are overcome by using a blue-emitting fluorescent dopant to harness higher-energy singlet excitons for blue emission and a green phosphorescent emitter co-doped with a red fluorescent emitter to harness lower-energy triplet excitons. The emission from the red fluorescent emitter is sensitized by the presence of a co-doped phosphor in a common conductive host. By lightly doping the sensitized layer with the fluorophore, less than complete transfer of triplets from the green phosphor results in a mixture of red and green emission. Combined with the emission from the singlet-harvesting blue fluorophore, the desired color balance may be achieved. With this method, a wide variety of fluorescent dyes can be used for WOLEDs while maintaining the high luminance and quantum efficiencies of the all-phosphor architectures. For the devices of the invention, the IQE can be as high as 100%.
Generally, an OLED comprises at least one organic layer disposed between and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer(s). The injected holes and electrons each migrate toward the oppositely charged electrode. When an electron and hole localize on the same molecule, an "exciton," which is a localized electron-hole pair having an excited energy state, is formed. Light is emitted when the exciton relaxes via a photoemissive mechanism. In some cases, the exciton may be localized on an excimer or an exciplex. Non-radiative mechanisms, such as thermal relaxation, may also occur, but are generally considered undesirable.
The initial OLEDs used emissive molecules that emitted light from their singlet states ("fluorescence") as disclosed, for example, in U.S. Pat. No. 4,769,292, which is incorporated by reference in its entirety. Fluorescent emission generally occurs in a time frame of less than 10 nanoseconds.
More recently, OLEDs having emissive materials that emit light from triplet states ("phosphorescence") have been demonstrated. Baldo et al., "Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices," Nature, vol. 395, 151-154, 1998; ("Baldo-I") and Baldo et al., "Very high-efficiency green organic light-emitting devices based on electrophosphorescence," Appl. Phys. Lett., vol. 75, No. 1, 4-6 (1999) ("Baldo-II"), which are incorporated by reference in their entireties. Phosphorescence may be referred to as a "forbidden" transition because the transition requires a change in spin states, and quantum mechanics indicates that such a transition is not favored. As a result, phosphorescence generally occurs in a time frame exceeding at least 10 nanoseconds, and typically greater than 100 nanoseconds. If the natural radiative lifetime of phosphorescence is too long, triplets may decay by a non-radiative mechanism, such that no light is emitted. Organic phosphorescence is also often observed in molecules containing heteroatoms with unshared pairs of electrons at very low temperatures. 2,2′-bipyridine is such a molecule. Non-radiative decay mechanisms are typically temperature dependent, such that an organic material that exhibits phosphorescence at liquid nitrogen temperatures typically does not exhibit phosphorescence at room temperature. But, as demonstrated by Baldo, this problem may be addressed by selecting phosphorescent compounds that do phosphoresce at room temperature. Representative emissive layers include doped or un-doped phosphorescent organometallic materials such as disclosed in U.S. Pat. Nos. 6,303,238 and 6,310,360; U.S. Patent Application Publication Nos. 2002-0034656; 2002-0182441; 2003-0072964; and WO-02/074015.
Generally, the excitons in an OLED are believed to be created in a ratio of about 3:1, i.e., approximately 75% triplets and 25% singlets. See, Adachi et al., "Nearly 100% Internal Phosphorescent Efficiency In An Organic Light Emitting Device," J. Appl. Phys., 90, 5048 (2001), which is incorporated by reference in its entirety. In many cases, singlet excitons may readily transfer their energy to triplet excited states via "intersystem crossing," whereas triplet excitons may not readily transfer their energy to singlet excited states. As a result, 100% internal quantum efficiency is theoretically possible with phosphorescent OLEDs. In a fluorescent device, the energy of triplet excitons is generally lost to radiationless decay processes that heat-up the device, resulting in much lower internal quantum efficiencies. OLEDs utilizing phosphorescent materials that emit from triplet excited states are disclosed, for example, in U.S. Pat. No. 6,303,238, which is incorporated by reference in its entirety.
Phosphorescence may be preceded by a transition from a triplet excited state to an intermediate non-triplet state from which the emissive decay occurs. For example, organic molecules coordinated to lanthanide elements often phosphoresce from excited states localized on the lanthanide metal. However, such materials do not phosphoresce directly from a triplet excited state but instead emit from an atomic excited state centered on the lanthanide metal ion. The europium diketonate complexes illustrate one group of these types of species.
Phosphorescence from triplets can be enhanced over fluorescence by confining, preferably through bonding, the organic molecule in close proximity to an atom of high atomic number. This phenomenon, called the heavy atom effect, is created by a mechanism known as spin-orbit coupling. Such a phosphorescent transition may be observed from an excited metal-to-ligand charge transfer (MLCT) state of an organometallic molecule such as tris(2-phenylpyridine)iridium(III).
As used herein, the term "triplet energy" refers to an energy corresponding to the highest energy feature discernable in the phosphorescence spectrum of a given material. The highest energy feature is not necessarily the peak having the greatest intensity in the phosphorescence spectrum, and could, for example, be a local maximum of a clear shoulder on the high energy side of such a peak.
The term "organometallic" as used herein is as generally understood by one of ordinary skill in the art and as given, for example, in "Inorganic Chemistry" (2nd Edition) by Gary L. Miessler and Donald A. Tarr, Prentice Hall (1998). Thus, the term organometallic refers to compounds which have an organic group bonded to a metal through a carbon-metal bond. This class does not include per se coordination compounds, which are substances having only donor bonds from heteroatoms, such as metal complexes of amines, halides, pseudohalides (CN, etc.), and the like. In practice organometallic compounds generally comprise, in addition to one or more carbon-metal bonds to an organic species, one or more donor bonds from a heteroatom. The carbon-metal bond to an organic species refers to a direct bond between a metal and a carbon atom of an organic group, such as phenyl, alkyl, alkenyl, etc., but does not refer to a metal bond to an "inorganic carbon," such as the carbon of CN or CO.
Substrate 110 may be any suitable substrate that provides desired structural properties. Substrate 110 may be flexible or rigid. Substrate 110 may be transparent, translucent or opaque. Plastic and glass are examples of preferred rigid substrate materials. Plastic and metal foils are examples of preferred flexible substrate materials. Substrate 110 may be a semiconductor material in order to facilitate the fabrication of circuitry. For example, substrate 110 may be a silicon wafer upon which circuits are fabricated, capable of controlling OLEDs subsequently deposited on the substrate. Other substrates may be used. The material and thickness of substrate 110 may be chosen to obtain desired structural and optical properties.
Anode 115 may be any suitable anode that is sufficiently conductive to transport holes to the organic layers. The material of anode 115 preferably has a work function higher than about 4 eV (a "high work function material"). Preferred anode materials include conductive metal oxides, such as indium tin oxide (ITO) and indium zinc oxide (IZO), aluminum zinc oxide (AlZnO), and metals. Anode 115 (and substrate 110) may be sufficiently transparent to create a bottom-emitting device. A preferred transparent substrate and anode combination is commercially available ITO (anode) deposited on glass or plastic (substrate). A flexible and transparent substrate-anode combination is disclosed in U.S. Pat. Nos. 5,844,363 and 6,602,540 B2, which are incorporated by reference in their entireties. Anode 115 may be opaque and/or reflective. A reflective anode 115 may be preferred for some top-emitting devices, to increase the amount of light emitted from the top of the device. The material and thickness of anode 115 may be chosen to obtain desired conductive and optical properties. Where anode 115 is transparent, there may be a range of thickness for a particular material that is thick enough to provide the desired conductivity, yet thin enough to provide the desired degree of transparency. Other anode materials and structures may be used.
Hole transport layer 125 may include a material capable of transporting holes. Hole transport layer 130 may be intrinsic (undoped), or doped. Doping may be used to enhance conductivity. α-NPD and TPD are examples of intrinsic hole transport layers. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in United States Patent Application Publication No. 2003-02309890 to Forrest et al., which is incorporated by reference in its entirety. Other hole transport layers may be used.
The emissive region 135 is comprised of at least two emissive layers, each of which includes an organic material capable of emitting light when a current is passed between anode 115 and cathode 160. At least one of the emissive layers should comprise a fluorescent emissive material that emits in the high energy portion of the visible spectrum, preferably in the blue region. Another emissive layer should comprise a phosphorescent emitting material and a fluorescent emissive material. The emissive layers may also comprise a host material capable of transporting electrons and/or holes, doped with an emissive material that may trap electrons, holes, and/or excitons, such that excitons relax from the emissive material via a photoemissive mechanism. An emissive layer may comprise a single material that combines transport and emissive properties. Whether the emissive material is a dopant or a major constituent, the emissive layer may comprise other materials, such as dopants that tune the emission of the emissive material. Emissive region 135 may include a plurality of emissive materials capable of, in combination, emitting a desired spectrum of light. Examples of phosphorescent emissive materials include Ir(ppy)3. Examples of fluorescent emissive materials include DCM and DMQA. Examples of host materials include Alq3, CBP and mCP. Examples of emissive and host materials are disclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which is incorporated by reference in its entirety. Emissive material may be included in emissive region 135 in a number of ways. For example, an emissive small molecule may be incorporated into a polymer. This may be accomplished by several ways: by doping the small molecule into the polymer either as a separate and distinct molecular species; or by incorporating the small molecule into the backbone of the polymer, so as to form a co-polymer; or by bonding the small molecule as a pendant group on the polymer. Other emissive layer materials and structures may be used. For example, a small molecule emissive material may be present as the core of a dendrimer.
Many useful emissive materials include one or more ligands bound to a metal center. A ligand may be referred to as "photoactive" if it contributes directly to the photoactive properties of an organometallic emissive material. A "photoactive" ligand may provide, in conjunction with a metal, the energy levels from which and to which an electron moves when a photon is emitted. Other ligands may be referred to as "ancillary." Ancillary ligands may modify the photoactive properties of the molecule, for example by shifting the energy levels of a photoactive ligand, but ancillary ligands do not directly provide the energy levels involved in light emission. A ligand that is photoactive in one molecule may be ancillary in another. These definitions of photoactive and ancillary are intended as non-limiting theories.
Electron transport layer 145 may include a material capable of transporting electrons. Electron transport layer 145 may be intrinsic (undoped), or doped. Doping may be used to enhance conductivity. Alq3 is an example of an intrinsic electron transport layer. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in United States Patent Application Publication No. 2003-02309890 to Forrest et al., which is incorporated by reference in its entirety. Other electron transport layers may be used.
The charge carrying component of the electron transport layer may be selected such that electrons can be efficiently injected from the cathode into the LUMO (Lowest Unoccupied Molecular Orbital) energy level of the electron transport layer. The "charge carrying component" is the material responsible for the LUMO energy level that actually transports electrons. This component may be the base material, or it may be a dopant. The LUMO energy level of an organic material may be generally characterized by the electron affinity of that material and the relative electron injection efficiency of a cathode may be generally characterized in terms of the work function of the cathode material. This means that the preferred properties of an electron transport layer and the adjacent cathode may be specified in terms of the electron affinity of the charge carrying component of the ETL and the work function of the cathode material. In particular, so as to achieve high electron injection efficiency, the work function of the cathode material is preferably not greater than the electron affinity of the charge carrying component of the electron transport layer by more than about 0.75 eV, more preferably, by not more than about 0.5 eV. Similar considerations apply to any layer into which electrons are being injected.
Cathode 160 may be any suitable material or combination of materials known to the art, such that cathode 160 is capable of conducting electrons and injecting them into the organic layers of device 100. Cathode 160 may be transparent or opaque, and may be reflective. Metals and metal oxides are examples of suitable cathode materials. Cathode 160 may be a single layer, or may have a compound structure.
Blocking layers may be used to reduce the number of charge carriers (electrons or holes) and/or excitons that leave the emissive layer. An electron blocking layer 130 may be disposed between emissive layer 135 and the hole transport layer 125, to block electrons from leaving emissive layer 135 in the direction of hole transport layer 125. Similarly, a hole blocking layer 140 may be disposed between emissive layer 135 and electron transport layer 145, to block holes from leaving emissive layer 135 in the direction of electron transport layer 145. Blocking layers may also be used to block excitons from diffusing out of the emissive layer. The theory and use of blocking layers is described in more detail in U.S. Pat. No. 6,097,147 and United States Patent Application Publication No. 2003-02309890 to Forrest et al., which are incorporated by reference in their entireties.
As used herein, and as would be understood by one skilled in the art, the term "blocking layer" means that the layer provides a barrier that significantly inhibits transport of charge carriers and/or excitons through the device, without suggesting that the layer necessarily completely blocks the charge carriers and/or excitons. The presence of such a blocking layer in a device may result in substantially higher efficiencies as compared to a similar device lacking a blocking layer. Also, a blocking layer may be used to confine emission to a desired region of an OLED.
Generally, injection layers are comprised of a material that may improve the injection of charge carriers from one layer, such as an electrode or an organic layer, into an adjacent organic layer. Injection layers may also perform a charge transport function. In device 100, hole injection layer 120 may be any layer that improves the injection of holes from anode 115 into hole transport layer 125. CuPc is an example of a material that may be used as a hole injection layer from an ITO anode 115, and other anodes. In device 100, electron injection layer 150 may be any layer that improves the injection of electrons into electron transport layer 145. LiF/Al is an example of a material that may be used as an electron injection layer into an electron transport layer from an adjacent layer. Other materials or combinations of materials may be used for injection layers. Depending upon the configuration of a particular device, injection layers may be disposed at locations different than those shown in device 100. More examples of injection layers are provided in U.S. patent application Ser. No. 09/931,948 to Lu et al., which is incorporated by reference in its entirety. A hole injection layer may comprise a solution deposited material, such as a spin-coated polymer, e.g., PEDOT:PSS, or it may be a vapor deposited small molecule material, e.g., CuPc or MTDATA.
A hole injection layer (HIL) may planarize or wet the anode surface so as to provide efficient hole injection from the anode into the hole injecting material. A hole injection layer may also have a charge carrying component having HOMO (Highest Occupied Molecular Orbital) energy levels that favorably match up, as defined by their herein-described relative ionization potential (IP) energies, with the adjacent anode layer on one side of the HIL and the hole transporting layer on the opposite side of the HIL. The "charge carrying component" is the material responsible for the HOMO energy level that actually transports holes. This component may be the base material of the HIL, or it may be a dopant. Using a doped HIL allows the dopant to be selected for its electrical properties, and the host to be selected for morphological properties such as wetting, flexibility, toughness, etc. Preferred properties for the HIL material are such that holes can be efficiently injected from the anode into the HIL material. In particular, the charge carrying component of the HIL preferably has an IP not more than about 0.7 eV greater that the IP of the anode material. More preferably, the charge carrying component has an IP not more than about 0.5 eV greater than the anode material. Similar considerations apply to any layer into which holes are being injected. HIL materials are further distinguished from conventional hole transporting materials that are typically used in the hole transporting layer of an OLED in that such HIL materials may have a hole conductivity that is substantially less than the hole conductivity of conventional hole transporting materials. The thickness of the HIL of the present invention may be thick enough to help planarize or wet the surface of the anode layer. For example, an HIL thickness of as little as 10 nm may be acceptable for a very smooth anode surface. However, since anode surfaces tend to be very rough, a thickness for the HIL of up to 50 nm may be desired in some cases.
A protective layer may be used to protect underlying layers during subsequent fabrication processes. For example, the processes used to fabricate metal or metal oxide top electrodes may damage organic layers, and a protective layer may be used to reduce or eliminate such damage. In device 100, protective layer 155 may reduce damage to underlying organic layers during the fabrication of cathode 160. Preferably, a protective layer has a high carrier mobility for the type of carrier that it transports (electrons in device 100), such that it does not significantly increase the operating voltage of device 100. CuPc, BCP, and various metal phthalocyanines are examples of materials that may be used in protective layers. Other materials or combinations of materials may be used. The thickness of protective layer 155 is preferably thick enough that there is little or no damage to underlying layers due to fabrication processes that occur after organic protective layer 160 is deposited, yet not so thick as to significantly increase the operating voltage of device 100. Protective layer 155 may be doped to increase its conductivity. For example, a CuPc or BCP protective layer 160 may be doped with Li. A more detailed description of protective layers may be found in U.S. patent application Ser. No. 09/931,948 to Lu et al., which is incorporated by reference in its entirety.
The simple layered structure illustrated in
Structures and materials not specifically described may also be used, such as OLEDs comprised of polymeric materials (PLEDs) such as disclosed in U.S. Pat. No. 5,247,190, Friend et al., which is incorporated by reference in its entirety. By way of further example, OLEDs having a single organic layer may be used. OLEDs may be stacked, for example as described in U.S. Pat. No. 5,707,745 to Forrest et al, which is incorporated by reference in its entirety. The OLED structure may deviate from the simple layered structure illustrated in
Unless otherwise specified, any of the layers of the various embodiments may be deposited by any suitable method. For the organic layers, preferred methods include thermal evaporation, ink-jet, such as described in U.S. Pat. Nos. 6,013,982 and 6,087,196, which are incorporated by reference in their entireties, organic vapor phase deposition (OVPD), such as described in U.S. Pat. No. 6,337,102 to Forrest et al., which is incorporated by reference in its entirety, and deposition by organic vapor jet printing (OVJP), such as described in U.S. patent application Ser. No. 10/233,470, which is incorporated by reference in its entirety. Other suitable deposition methods include spin coating and other solution based processes. Solution based processes are preferably carried out in nitrogen or an inert atmosphere. For the other layers, preferred methods include thermal evaporation. Preferred patterning methods include deposition through a mask, cold welding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819, which are incorporated by reference in their entireties, and patterning associated with some of the deposition methods such as ink-jet and OVJP. Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, and preferably containing at least 3 carbons, may be used in small molecules to enhance their ability to undergo solution processing. Substituents having 20 carbons or more may be used, and 3-20 carbons is a preferred range. Materials with asymmetric structures may have better solution processibility than those having symmetric structures, because asymmetric materials may have a lower tendency to recrystallize. Dendrimer substituents may be used to enhance the ability of small molecules to undergo solution processing.
The molecules disclosed herein may be substituted in a number of different ways without departing from the scope of the invention. For example, substituents may be added to a compound having three bidentate ligands, such that after the substituents are added, one or more of the bidentate ligands are linked together to form, for example, a tetradentate or hexadentate ligand. Other such linkages may be formed. It is believed that this type of linking may increase stability relative to a similar compound without linking, due to what is generally understood in the art as a "chelating effect."
Devices fabricated in accordance with embodiments of the invention may be incorporated into a wide variety of consumer products, including flat panel displays, computer monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads up displays, fully transparent displays, flexible displays, laser printers, telephones, cell phones, personal digital assistants (PDAs), laptop computers, digital cameras, camcorders, viewfinders, micro-displays, vehicles, a large area wall, theater or stadium screen, or a sign. Various control mechanisms may be used to control devices fabricated in accordance with the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a temperature range comfortable to humans, such as 18 degrees C. to 30 degrees C., and more preferably at room temperature (20-25 degrees C.).
The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors may employ the materials and structures. More generally, organic devices, such as organic transistors, may employ the materials and structures.
The devices of the present invention have an emissive region which comprises a fluorescent layer having a first fluorescent emitting material as a dopant in a host material and a phosphorescent-sensitized fluorescent layer comprising a second fluorescent emitting material and a phosphorescent emitting material as dopants in a host material. In preferred embodiments, the first fluorescent emitting material is a blue-emitting material and the phosphorescent-sensitized fluorescent layer has a green-emitting phosphorescent material and a red-emitting fluorescent material. The emission from the second (red) fluorescent dopant is sensitized by the presence of a co-doped phosphorescent material in the common host of the phosphor-sensitized emissive layer. By lightly doping the sensitized layer with the second fluorescent emissive material, less than complete transfer of triplets from the phosphorescent material results in a combined emission from the two emissive materials of the phosphor-sensitized layer. In preferred embodiments the combined emission is a mixture of red and green emission from the fluorescent emitter and the phosphorescent emitter, respectively. Combined with the emission from the singlet-harvesting blue fluorophore, the desired white color balance is achieved. With this method, a wide variety of fluorescent dyes can be used for WOLEDs while maintaining the high luminance and quantum efficiencies.
The devices of the present invention utilize the first fluorescent emitter (typically a blue emitter) for harvesting the singlet fraction of the generated excitons and a phosphorescent emitter for the triplet fraction of the generated excitons. For a white device, the devices of the invention utilize a blue fluorescent material in combination with a green phosphorescent emitting material and a red fluorescent material to yield high power efficiency, stable color balance and the potential for 100% internal quantum efficiency. Two distinct modes of energy transfer channel nearly all of the triplet energy to the phosphorescent emitting material(s), while retaining the singlet energy exclusively on the fluorescent emissive material. Additionally, eliminating the exchange energy loss from the singlet excitons allows for up to about 20% increased power efficiency compared to a phosphorescent-only device. This device architecture is distinctive in that the singlet and triplet excitons may be harvested along independent channels, and thus the transfer from host to dopant for both species can be separately optimized to be nearly resonant, thereby minimizing energy losses while maintaining a unity IQE.
For devices having optimized efficiency, it is desirable that the fluorescent layer harvest approximately all of the singlet excitons, and the phosphorescent-sensitized fluorescent layer harvest approximately all of the triplet excitons. The excitons become located on the dopant materials (i.e., the fluorescent dopant of the fluorescent layer and the phosphorescent dopant of the phosphorescent-sensitized layer) through a combination of charge trapping and direct exciton formation on the dopant, and transfer from host to dopant via Dexter and/or Forster mechanisms. Thus, for optimized devices, it is desirable that greater than about 90%, and preferably greater than about 95%, of the singlet excitons are utilized by the fluorescent layer(s), and that greater than about 90%, and preferably greater than about 95%, of the triplet excitons utilized by the phosphorescent-sensitized fluorescent layer.
The invention provides efficient white-emitting or multi-colored emitting OLEDs. For white emitting devices, the combined emission of the emitting materials gives a white emission from the device. For preferred white-emitting devices, the two or more emissive dopants are selected so that the combined emission from the device has a CIE range between X=0.37�0.07 and Y=0.37�0.07. More preferably, the CIE coordinates are X=0.35�0.05, and Y=0.35�0.05 and even more preferably X=0.33�0.02, Y=0.33�0.02. The term "multicolored" refers to the emission from a device that results from two or more different emitting materials that each have different emissive spectra. Although a high CRI value may be preferred for certain lighting applications, the devices of the present invention may be used to produce a light source that provides other colors as well. In preferred embodiments, the devices of the present invention are capable of achieving an external quantum efficiency of at least about 6%.
For white-emitting devices for illumination, the color rendering index (CRI) may be an important consideration, as the CRI gives an indication of how well the light source will render the colors of objects it illuminates. For preferred white-emitting devices of the invention, the CRI value is at least about 75, more preferably at least about 80, and most preferably at least about 85.
The emissive region may be comprised of multiple layers such that the blue fluorescent emitting material(s) and the emitters of the phosphor-sensitized layer are doped into different layers within the emissive region. Recombination occurs predominantly either in the host matrix or on the fluorescent dopant. In either case the singlet exciton will be trapped and emit from the fluorescent dopant. The triplet exciton will then diffuse through the host matrix to the phosphorescent dopant(s), where it will be trapped and emit or be further transferred to the co-doped fluorescent dopant.
In one embodiment of the invention, the emissive region comprises two adjacent emissive layers, a fluorescent emissive layer and a phosphor-sensitized phosphorescent/fluorescent emissive layer. A representative structure of a device according to this embodiment is depicted in
In another in a preferred embodiment, the emissive region comprises a phosphor-sensitized phosphorescent/fluorescent layer or layers sandwiched between two fluorescent layers. Representative device structures according to this embodiment are depicted in
In preferred embodiments of the invention, the fluorescent-only layer(s) is separated from the phosphor-sensitized phosphorescent/fluorescent layer by a spacer layer. Representative structures of devices according to this embodiment are depicted in
In preferred embodiments of the invention the host material for the fluorescent-only layer and phosphor-sensitized layer are the same material. In the embodiments of the invention having a spacer layer separating the fluorescent-only layer and phosphor-sensitized layer, the spacer layer is also preferably composed of the host material. This allows for optimal performance and the elimination of energy barriers to transport.
In preferred embodiments of the invention, the emissive region of the device is composed of layers such that the emissive region has the following structure:
fluorescent layer/phosphor-sensitized layer;
fluorescent layer/spacer/phosphor-sensitized layer;
fluorescent layer/spacer/phosphor-sensitized layer/fluorescent layer;
fluorescent layer/phosphor-sensitized layer/spacer/fluorescent layer; and
fluorescent layer/spacer/phosphor-sensitized layer/spacer/fluorescent layer.
For each configuration of the emissive region, it is preferred that layers directly adjacent to the emissive region block excitons and the opposite charge that they conduct.
In preferred embodiments, the devices of the invention are constructed so that recombination occurs primarily in the fluorescent layer or layers. Even more preferably, the device is constructed so that the recombination zone is at the interface of a fluorescent layer and an adjacent transport layer (HTL or ETL) or blocking layer. The singlet excitons that are generated by the recombination of a hole and an electron are trapped by and emit from the fluorescent emissive material. The thickness of a fluorescent layer and the concentration of a fluorescent emitting material in the layer are adjusted so that the singlet excitons are completely trapped at the fluorescent emitting material. The triplet of the fluorescent dopant should be of sufficiently high energy that the triplet excitons are not trapped at the fluorescent dopant. Thus, in a preferred embodiment of the invention greater than about 50% of the recombination occurs within the fluorescent layer or layers, and in particularly preferred embodiments, greater than 70% of the recombination occurs within the fluorescent layer or layers.
The zone of recombination can be adjusted in a multilayer device by adjusting the materials used in one or more of the layers (for example the host material, HTL, ETL, and/or blocking layer) and by adjusting the thicknesses of the various layers. Further, recombination can be localized at the interface between layers made of dissimilar materials. Thus, recombination can be localized by the interface between the emissive region and an adjacent layer or layers, for example the HTL, ETL, blocking layer, etc.
The triplet excitons that are generated upon recombination diffuse from the recombination zone in the fluorescent layer(s) into the phosphor-sensitized emissive layer. The triplet excitons will diffuse into the phosphor doped regions and be trapped. The emission from the fluorescent dopant of the phosphor-sensitized layer is sensitized by the presence of a co-doped phosphorescent material in the common host. By lightly doping the phosphor-sensitized layer with a fluorescent emissive material, less than complete transfer of triplets from the phosphorescent material results in a combined emission from the two emissive materials of the phosphor-sensitized layer. With the appropriate choice of materials, each dopant will emit with high efficiency and a high overall efficiency will be achieved for the device. Further, the combined color emission from the phosphorescent dopant and the fluorescent dopant of the phosphor-sensitized emissive layer can be tuned by the selection of the dopant materials and the relative concentration of phosphorescent and fluorescent dopants. It is preferable that the concentration of the phosphorescent dopant be high enough to harvest essentially all of the triplet excitons.
In a preferred embodiment of the invention, the fluorescent emissive material of the fluorescent-only layer is a blue-emitting fluorescent material. To date, phosphorescent blue emitters have generally displayed poor operational stability in OLEDs. Fluorescent blue emitters are selected to be highly efficient and to have good operational lifetimes in OLEDs. Preferred fluorescent blue emitters include polyaromatic compounds such as 9,10-di(2-naphthylantracene), perylenes, phenylenes, and fluorenes, with 4,4′-(Bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl being a particularly preferred fluorescent blue emitter. (see, K. O. Cheon, and J. Shinar, J. Appl. Phys. 81, 1738 (2002); and C. Hosokawa, H. Tokailin, H. Higashi, and T. Kusumoto, J. Appl. Phys. 78, 5831 (1995), each of which is incorporated herein in their entirety.) Preferred fluorescent blue emitters may be found in C. H. Chen, J. Shi, and C. W. Tang, "Recent Developments in Molecular Organic Electroluminescent Materials," Macromol. Symp. 125, pp. 1-48 (1997) and the references cited therein; L. S. Hung and C. H. Chen, "Recent progress of molecular organic electroluminescent materials and devices," Mat. Sci and Eng. R, 39 (2002), pp. 143-222 and the references cited therein, each of which is incorporated herein by reference in their entirety. Other preferred fluorescent blue emitters include arylpyrenes as described in the co-pending application entitled "Arylpyrene Compounds," Ser. No. 11/097,352, filed Apr. 4, 2005, which is incorporated herein by reference in its entirety. Other preferred blue fluorescent emitters include arylenevinylene compounds as described in U.S. Pat. Nos. 5,121,029 and 5,130,603, which are incorporated herein by reference in their entirety. The fluorescent blue emitting material is preferably doped into a host material at a concentration of about 1% to about 15%. The fluorescent layer preferably has a thickness of between about 50 Å to about 200 Å.
For white-emitting devices, green-to-red (G-R) components of the white light are provided by a phosphorescent emitting materials co-doped with a fluorescent emitting material in the phosphor-sensitized layer. The G-R emitting materials are chosen such that the sum of their spectra cover the range from green to red. In this way, about 25% of the excitons would produce blue light from the fluorescent blue emitting material, while the remaining 75% of the excitons are used for the G-R part of the emission spectrum. This is roughly the ratio of blue to G-R in the typical white OLED spectrum. This approach to a white OLED may provide a stable color balance as the drive voltage is increased and an enhanced device stability. The enhanced stability results from having long lived fluorescent blue emitting materials used in conjunction with long lived G-R emitting phosphorescent emitting materials in a single device.
Preferred phosphorescent green emitters may be found in Baldo, M. A., Thompson, M. E. & Forrest, S. R. High efficiency fluorescent organic light-emitting devices using a phosphorescent sensitizer, Nature 403, 750-753 (2000); and in U.S. Pat. No. 6,830,828, each of which is incorporated herein by reference in their entirety. The phosphorescent green emitting material is preferably doped into a host material at a concentration of about 2% to about 20%.
Fluorescent red emitting materials may be found in U.S. Pat. Nos. 5,989,737, 4,769,292, 5,908,581, and 5,935,720, each of which is incorporated herein by reference in their entirety. Preferred red fluorescent materials include the DCM/DCJ class of red emitters (such as 4-(dicyanomethylene)-2methyl-6-(p-dimethylaminostyryl)-4H-pyran and -j ulolidyl derivatives), and quinacridones. In the phosphor-sensitized emissive layer, the presence of the co-doped phosphorescent emitting material sensitizes the fluorescent emitting material for emission. Thus, this fluorescent emitting material may be present in very low concentrations. Generally, red emitting dopants act as carrier trapping sites, and consequently the operating voltage is increased due to the reduced carrier mobility. In the phosphor-sensitized WOLED, the red dopant is only lightly doped, thereby preventing significant carrier trapping on the fluorophore. Moreover, the power efficiency is increased over that expected for an all-phosphor, doped emissive region by eliminating exchange energy losses incurred by the very high energy required to excite the blue phosphor from the singlet and triplet states of the fluorescent host. In preferred embodiments the fluorescent emitting material of the phosphor-sensitized layer is present at a concentration of less than about 1%, preferably less than about 0.5%, and more preferably less than about 0.1%.
It is understood that the various embodiments described herein are by way of example only, and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures without deviating from the spirit of the invention. It is understood that various theories as to why the invention works are not intended to be limiting. For example, theories relating to charge transfer are not intended to be limiting.
Material Definitions:
As used herein, abbreviations refer to materials as follows:
Specific representative embodiments of the invention will now be described, including how such embodiments may be made. It is understood that the specific methods, materials, conditions, process parameters, apparatus and the like do not necessarily limit the scope of the invention.
The WOLEDs were grown on glass substrates pre-coated with a 150-nm-thick, ˜20 ohm/sq indium tin oxide (ITO) anode layer. Prior to organic layer deposition, the ITO coating was exposed to a UV+ozone flux for 5 minutes following degreasing in detergent solution and solvents. The organic multilayer structure was deposited at a rate of 1-5 Å/sec without breaking vacuum, using materials that were previously purified by repeated temperature gradient vacuum sublimation before loading into a vacuum evaporation chamber with a base pressure of ˜10−7 Torr. The doped layers of the emissive region were grown by co-deposition of the emissive dopant and CBP. The dopant concentrations in the emissive region were varied by using a mask with an aperture able to translate in vacuum during deposition. The emissive region was capped by a 30-nm-thick Bphen exciton blocking layer. Finally, a 50-nm-thick Al cathode is deposited through a Mo shadow mask with an array of circular, 1.0-mm-diameter openings. Masking for cathode deposition was completed following organic layer deposition in an ultrahigh purity nitrogen-filled glove box with <1 ppm water and oxygen. Current-voltage and external quantum efficiency measurements were carried out using a semiconductor parameter analyzer (HP 4156C) and a calibrated Si photodiode (Hamamatsu S3584-08) following standard procedures. S. R. Forrest, D. D. C. Bradley, and M. E. Thompson, Adv. Mater. 15, 1043 (2003).
In one set of OLEDs employing only a green and red doped emissive region, a 50-nm-thick NPD was grown, followed by a 15-nm-thick green-red emissive layer consisting of 8% Ir(ppy)3 co-doped with DCJTB at various concentrations in CBP, and then capped by a 30-nm-thick Bphen exciton blocking layer. The phosphor-sensitized emissive region lacking the blue doped layer was used to investigate energy transfer as a function of DCJTB concentration. As shown in
A WOLED was prepared as indicated above, except that the emissive region consisted of a 10-nm-thick fluorescent blue region (10% BCzVBi doped in CBP), a 2-nm-thick undoped CBP spacer, a 15-nm-thick green+red emissive layer consisting of Ir(ppy)3 co-doped with 0.08% DCJTB in CBP, a second 2-nm-thick undoped CBP spacer, and a second 10-nm-thick blue fluorescent region. The emissive region was capped by a 30-nm-thick Bphen layer, as above.
The WOLED structure is shown in
Based on these results from example 1, phosphor-sensitized WOLEDs were grown with 0.08% DCJTB, with the Ir(ppy)3 concentration varied from 0% to 8% in CBP, also including the blue fluorescent doped zones and accompanying spacers at the edges of the EML. The WOLED efficiencies and electroluminescence spectra are shown in
In the absence of the Ir(ppy)3 sensitizer, the efficiencies drop sharply to 3.2�0.3% and 3.9�0.4 lm/W, as expected for a purely fluorescent device. As seen in
The emission spectral dependence on current density is shown in
In summary, we have demonstrated high efficiency white OLEDs employing a phosphor-sensitizer combined with blue and red fluorescent dopants. By changing the concentrations of the red fluorophore and the green phosphorescent emitter/sensitizer, we obtain efficient triplet transfer from the blue doped zones at the edge(s) of the EML to DCJTB via phosphorescent sensitizer, Ir(ppy)3, while at the same time harvesting nearly all the singlets originating in the CBP host by the blue dopant itself. The WOLEDs have an extended carrier recombination zone, which leads to high external efficiencies at high brightness. The devices reach a maximum forward viewing external efficiency of ηext=8.5�1% for the WOLED with 8% Ir(ppy)3, and a total efficiency of ηext,tot=13.1�1% at a luminance of 800 cd/m2. This corresponds to a total power efficiency of ηp,tot=20.2�2 lm/W with a CRI of 79. These results demonstrate that phosphor-sensitized WOLEDs constitute a simple and efficient (100% IQE) route to achieving high brightness sources for indoor lighting using only a single phosphorescent dopant.
While the present invention is described with respect to particular examples and preferred embodiments, it is understood that the present invention is not limited to these examples and embodiments. The present invention as claimed therefore includes variations from the particular examples and preferred embodiments described herein, as will be apparent to one of skill in the art.
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|Yang et al., "Use of Poly(9-vinylcarbazole) as host material for iridium complexes in high-efficiency organic light emitting devices", Japanese J. Appl. Phys., Part 2, No. 8A, vol. 39, pp. L828-829 (Aug. 1, 2000).
|Zhang et al., "White organic light-emitting devices based on 4,4'-bis(2,2'-deiphenyl vinyl)-l,1'-biphenyl and phosphorescence sensitized 5,6,11,12-tetraphenylaphthacene", Appl. Phys. Lett. 86: 11112-1 to 11112-3.
|Citing Patent
|Filing date
|Publication date
|Oct 4, 2012
|Apr 29, 2014
|Semiconductor Energy Laboratory Co., Ltd.
|Light-emitting element, light-emitting device, and electronic device
|Oct 27, 2006
|Feb 3, 2015
|The University Of Southern California
|Materials and architectures for efficient harvesting of singlet and triplet excitons for white light emitting OLEDs
|Dec 12, 2007
|Feb 17, 2015
|Sony Corporation
|Organic electroluminescent device and display apparatus
|Oct 27, 2006
|May 1, 2008
|Thompson Mark E
|Materials and architectures for efficient harvesting of singlet and triplet excitons for white light emitting OLEDs
|Dec 12, 2007
|Feb 12, 2009
|Sony Corporation
|Organic electroluminescent device and display apparatus
|U.S. Classification
|313/504, 313/506
|International Classification
|Cooperative Classification
|European Classification
|Jul 25, 2006
Owner name: TRUSTEES OF PRINCETON UNIVERSITY, THE, NEW JERSEY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FORREST, STEPHEN;KANNO, HIROSHI;REEL/FRAME:018001/0780;SIGNING DATES FROM 20060713 TO 20060718
|Apr 12, 2010
Owner name: ENERGY, UNITED STATE DEPARTMENT OF,DISTRICT OF COL
Free format text: CONFIRMATORY LICENSE;ASSIGNOR:PRINCETON UNIVERSITY;REEL/FRAME:024218/0546
Effective date: 20100112
|Dec 14, 2010
|Certificate of correction
|Feb 25, 2013
|Fee payment
Year of fee payment: 4
|Feb 9, 2017
|Fee payment
Year of fee payment: 8


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1 Eloura Circuit Taylors Hill 3037 VIC
Ready To Move In!
Situated in the fantastic area of Taylors Hill, positioned perfect in a private and prime location is this fantastic home that offers a flowing floor plan, is immaculately presented and offers something for everyone. Perfect for first home buyers looking to break into the booming Taylors Hill market or savvy investors. Located just minutes away from Primary schools, High schools, Taylors Hill community centre, Watervale Shopping Centre and Public transport.
Comprising of four generous sized bedrooms with built in robes, Master with large walk- in robe and full en-suite including two vanities and a double shower. Situated towards the rear of the property awaits the spacious kitchen with top of the range stainless steel appliances and plenty of storage options. Outside you will find a fantastic low maintenance backyard with including a pergola for year round entertaining.
Also featuring: Laundry with outside access, Ducted heating, Split system cooling, Central and spacious bathroom, Alarm system and a Double car lock up garage with internal access to the property.
Don't Delay, Enquire Today!
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YPA Estate Agents Taylors Lakes
Taylors Lakes VIC, 3038
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Real Estate For Sale in Taylors Hill, VIC 3037 priced between $350,000 and $660,000

subset: commoncrawl


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Milwaukee is known for its historic wedding venues, but we've got some really great modern venues as well! If you are into crisp, clean aesthetic, modern architecture, and updated amenities, then this list of wedding and event venues is for you.
If there's any modern venues we missed, please let us know in the comments! Now enjoy these 14 modern wedding venues listed in no particular order: [Read more…]


text: z bug 111 (9:21:02 PM): sore loser z bug 111 (9:21:04 PM): lol whos Caleb (9:21:20 PM): hahahaha z bug 111 (9:21:22 PM): it is time to heal america sucka whos Caleb (9:21:27 PM): lol whos Caleb (9:21:38 PM): by stripping us of our constitutional rights whos Caleb (9:21:44 PM): starting with the second amendment z bug 111 (9:22:09 PM): oh lord z bug 111 (9:22:12 PM): he's not gonna take away your toys whos Caleb (9:22:39 PM): just going to prevent us from getting more, or ammunition, or the right to use them. z bug 111 (9:23:43 PM): what part of his gun control platform do you have a problem with? whos Caleb (9:23:50 PM): All of it. whos Caleb (9:23:54 PM): hes going at it completely wrong z bug 111 (9:24:00 PM): lol z bug 111 (9:24:03 PM): is this the #1 issue for you z bug 111 (9:24:06 PM): in the campaign? whos Caleb (9:24:08 PM): no whos Caleb (9:24:15 PM): he didnt really focus on it in his campaign whos Caleb (9:24:27 PM): it actually seemed like he tried to avoid it z bug 111 (9:24:29 PM): well, i wouldn't worry too much whos Caleb (9:24:34 PM): I would. z bug 111 (9:24:40 PM): gun control is one of those things that's a state thing whos Caleb (9:24:54 PM): Unless he imposes federal legistation/regulation z bug 111 (9:25:02 PM): he has nothing to gain from doing that whos Caleb (9:25:20 PM): yeah, but its just something that he apparently belives in z bug 111 (9:25:27 PM): but i guess notify me when he does whos Caleb (9:25:35 PM): yeah, it wont be immediate z bug 111 (9:25:40 PM): gun control is an issue z bug 111 (9:25:44 PM): that comes up every election cycle z bug 111 (9:25:47 PM): because it's a wedge issue whos Caleb (9:25:48 PM): but everything firearm related has spiked nationwide z bug 111 (9:25:55 PM): but no one does anything really substantive about it whos Caleb (9:26:19 PM): yeah, but now congress seems to have shifted power towards the democrats z bug 111 (9:26:35 PM): trust me, dude z bug 111 (9:26:46 PM): the democrats have bigger things to worry about than gun control right now whos Caleb (9:26:56 PM): once that assault wepons ban rolls around, nothing to inhibit it whos Caleb (9:27:04 PM): I know, I', not saying its goin to happen right away whos Caleb (9:27:14 PM): just saying that it can, and most likely will happen. z bug 111 (9:27:35 PM): idon't think it's likely at all z bug 111 (9:27:46 PM): gun control isn't on most voters minds z bug 111 (9:28:04 PM): but i guess time will tell whos Caleb (9:28:12 PM): trust me, in the gun owners community, they've dug up a lot of direct statements addressing obama's views on gun control whos Caleb (9:28:30 PM): as of late, he's the most anti-gun presidential candidate in the history of the US


text:
We stock a huge range of kitesurfing kites from a variety of top brands including Cabrinha, RRD, Airush, Slingshot and Ocean Rodeo. We've got kites from all of the listed brands in a variety of colours, styles, sizes and prices to suit anyone's taste, price range or ability from beginner to expert and anything from freeride to b and everything in between. All of the kites that we stock contain various features to make your kiting experience as fun as possible, the Cabrinha FX Crossover is a great example with features such as three struts, highly responsive platform for quick acceleration and boost for airs, expanded C-shaped arc allows for more aggressive kite loops, positive and direct steering and quick relaunch make it a perfect intermediate to advanced kite. All of the features on the FX will benefit you greatly on the water in multiple ways.
If you have any questions about the kitesurfing kites that we stock please don't hesitate to contact us on 01202 738448
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FRC believes the context for the full expression of human sexuality is within the bonds of marriage between one man and one woman. Upholding this standard of sexual behavior would help to reverse many of the destructive aspects of the sexual revolution, including sexually transmitted disease rates of epidemic proportion, high out-of-wedlock birth rates, adultery, and homosexuality.
In accordance with this position, the best sexuality education embraces sexual abstinence outside of marriage. The abstinence-until-marriage approach promotes optimal physical and psycho-social outcomes for youth and young adults. FRC maintains that contraceptive-based or comprehensive sex education is destructive, providing mixed risk messaging and an overly narrow focus on physical health alone.
FRC does not consider homosexuality, bi-sexuality, and transgenderism as acceptable alternative lifestyles or sexual "preferences"; they are unhealthy and destructive to individual persons, families, and society. Compassion compels us to support the healing of those who wish to change their destructive behavior.
Policy Publications
- Transgender Policy Could Cost Military Billions Over Ten Years by Peter Sprigg
- Regulations Regarding Sexual Orientation and Gender Identity by FRC
- Bathroom Incidents by FRC
- Title IX and Transgendered Students by FRC
- Should Individuals Who Identify as Transgender Be Permitted to Serve in the Military? by Peter Sprigg
- The Transgender Movement and "Gender Identity" in the Law by Peter Sprigg
- Questions and Answers about the Proposed Federal 'Equality Act' by Peter Sprigg
- Can There Be 'Compromise' Between Sexual Orientation/Gender Identity Non-Discrimination Laws and Religious Liberty Protections? by Peter Sprigg
- The Inequalities of the 'Equality Act' by FRC
- Understanding and Responding to the Transgender Movement by Dale O'Leary and Peter Sprigg
- Sexual Orientation and Gender Identity (SOGI) Laws: A Threat to Free Markets and Freedom of Conscience and Religion by Peter Sprigg
- Obama Executive Order on "Sexual Orientation" and "Gender Identity" by Peter Sprigg and Travis Weber
- Protect Client and Therapist Freedom of Choice Regarding Sexual Orientation Change Efforts by Peter Sprigg
- Gender Identity Protections and "Bathroom Bills" by Peter Sprigg
FRC Blog
Category Archives: Human Sexuality
- Supreme Court Stands by and Watches as Religious Freedom Is Curtailed by Travis Weber (July 2016)
- Has Public Opinion Shifted Under the Gavel?: Obergefell After One Year by Cathy Ruse (June 2016)
- Why Same-Sex Marriage Will Pave the Way to Polygamy by Peter Sprigg (June 2016)
- Transgender Activists Put Ideology Above Safety by Peter Sprigg (April 2016)
- Should Individuals Who Identify as Transgender Be Permitted to Serve in the Military? by Peter Sprigg (Feb. 2016)
- The Transgender Movement and 'Gender Identity' in the Law' by Peter Sprigg (Feb. 2016)
Legislative Testimony
- Testimony by Peter Sprigg in Opposition to Hawaii Senate Bill No. 2615 - Peter Sprigg (Feb. 2016)
- Testimony by Peter Sprigg in Opposition to Vermont Bill S. 132 - Peter Sprigg (Feb. 2016)
- Testimony by Peter Sprigg in Opposition to Maryland House Bill 1265 - Peter Sprigg (March 2014)
- Testimony by Peter Sprigg in Opposition to Maryland Senate Bill 212 - Peter Sprigg (Feb. 2014)
- Testimony of Peter Sprigg before the Maryland Senate Judicial Proceedings Committee - Peter Sprigg (Feb. 2013)


text:
One of the basics of small business banking is to set-up a business bank account. This fundamental business function is often lost with new and part-time business co-mingling personal and business funds. Using a personal bank account for small business banking is common among part-time business like multi-level marketing and self-employed sole-proprietors such as realtors and consultants.

Frequently, business owners try to process business transactions through their personal bank accounts in an effort to reduce expenses and bank fees. Unwittingly, they may be creating potential problems for the business in the future.

Not convinced that you should keep your personal and small business banking separate? Here are five reasons.

1. Hobby Business Classification

IRS rules stipulate that only businesses can deduct business expenses. While there are specific guidelines for determining whether an entity is a business or a hobby, If your business goes through your personal account you may be giving the impression that this is a hobby (a personal bank account for business creates a harder time convincing the government you are operating a business).

2. Tax Time Nightmare

When it comes time to declare income and expenses from the business, personal transactions will have to be separated from business transactions. It will be a nightmare and time burden going through all transactions and figuring out business from personal.

3. Limited Audit Trail

While the government doesn't require you to have a specific record keeping method or separate bank account, it does require that whatever method you use, that all records be accurate, complete, permanent and show a clear record of income and deductions. Providing a separate business statement and record provides a clear audit trail.

4. Missed Deductions

Co-mingling your small business banking with personal creates a mess of transactions on your account statement. It is easy to overlook or miss deductions you may be entitled to. Whether you or an accountant will be preparing the tax return, messy record keeping will cost more in time, money, and possible missed deductions.

5. Lack of Professionalism

If you have clients who write checks to you, check writing in your personal name as opposed to business can convey that your company is a part-time or less-than-serious venture. Even if your business is part-time, take it seriously and your clients will, too.

Take the time to open a small business banking account to simplify your record keeping and life. Shop around for the best deal. Small business banking varies in fees and features. The costs of a business account are far less than the benefits to your business. Fees are partly tax deductible as an expense. Don't forget to consider that your business may grow. Opening a business account with a bank earlier can help with required financing in the future. Remember run your business as a business.

Edited by Alyssa Gregory


text:
Welcome, Please Sign In
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By creating an account at Water Fowl Ireland you will be able to shop faster, be up to date on an orders status, and keep track of the orders you have previously made.
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I am a returning customer.


text:
If an item you ordered from TextbookRush does not meet your expectations due to an error on our part, simply fill out a return request and then return it by mail within 30 days of ordering it for a full refund of item cost.
Learn more about our returns policy
Limited time offer:
Get the first one free! (?)
All the information you need in one place! Each Study Brief is a summary of one specific subject; facts, figures, and explanations to help you learn faster.
List price: $18.95Copyright year: 1997Publisher: Free PressPublication date: 3/1/1997Binding: PaperbackPages: 400Size: 5.75" wide x 8.25" long x 1.25" tall Weight: 1.144Language: English
Fung Yu-lan's philosophical works, which developed under the influence of American pragmatism and Neo-Realism, as well as Confucianism and Marxism, show a marked transition from traditional interpretations to radical Maoist thinking. After receiving his B.A. from Beijing University, Fung went to Columbia University to complete his doctorate in philosophy. Still sympathetic to Confucianism, he returned to China in the late 1920s and set to work applying his newly learned pragmatic methods to the study of classical Chinese philosophy. The development of this comparative East-West perspective can be seen in both his Philosophy of Life and his two-volume A History of Chinese Philosophy (1931, 1934). In attempting to overturn many traditional interpretations, he soon earned a reputation for himself, not only in China, but also in the West. By the late 1930s, Fung had started to formulate his own philosophical system---a rational formalism that reinterpreted the apparently ontological categories of Neo-Confucianism (such as dao, li, and qi, also romanized as tao, li, and ch'i ) into logical functions. Of his works at this time, New Li Hsueh (The New Rational Philosophy) was his most important and famous expression of Neo-Confucianism in light of modern philosophy. With the Communist Revolution, Fung's ideas came under attack as being overly idealistic. This led to the rethinking of his former historical and logical positions more in light of dialectical materialism. Fung eventually became a supporter of Mao Tse-tung's anti-Confucian campaign during the 1970s and served as intellectual consultant to Mao's wife, Chiang Ch-ing. Nevertheless, Fung never quite fit the paradigm of the Maoist philosopher, and until his death his philosophy periodically underwent official criticism as being overly "abstract" and "idealistic." His "philosophical career" ended when Chiang's group fell from power shortly after Mao's death.
*A minimum purchase of $35 is required. Shipping is provided via FedEx SmartPost®
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Build an Online Store
Anggaran $3750-11250 MXN
Project: an online TOUR "store" /site aim to toursits from cruise ships.
The platform should be capable to add different tours in each destination, beta version should focus only in one city. (see images attached)
The customer should have an easy and trustworthy journey all the way from searching, booking, and paying.
Payment Methods: paypal or payooner.
IMPORTANT: Most tours would be for groups only, where there is a minimum to book. (see images attached)
**more information will be provided to the selected freelancer upon review**
61 freelancer menawar pada rata-rata $17090 untuk pekerjaan ini
With Freelancer Preferred badge bound to give 100% Quality (Let's Chat) Hello, A great team is here for your service!! I read the project description properly, and I agreed to fulfill 100% of all your requiremen Lagi
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Dear Employeer, Greetings from us!!! We are extremely experienced on eCommerce site development. Our Experties on WooCommerce // OpenCart // Prestashop // Magento // Shopify and any kind of ecommerce solut Lagi
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text:
CLSC Snapback Cap by CLSC Co.
Posted by Kevin, October 28th, 2014 02:10 pm under Snapback, Street Wear
Posted by Kevin, October 28th, 2014 02:10 pm under Snapback, Street Wear
The rapidly rising streetwear label, CSLC Co., shows us their new headwear pieces. The CLSC snapback cap is aptly named with its simple but fresh look. The cap comes in two colorways: Black and Royal Blue. The featured cap is the standout piece with its all-over Royal Blue look complemented by tonal woven eye-lets and top-button. The front panel shows a contrasting hit in the form of a White embroidered logo. A branded flag logo is situated on the left side panel for an additional contrasting hit. A tonal back-snap finishes it off. Get this cap online at www.knyew.com.


text:
The Seal Lullaby - Makayla Lynn and Abigail (12 and 13 years old)
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CONVERSATIONAL COURSE IN GERMAN FOR BEGINNERS (Part time)University of Mumbai
Price on request
Important information
- Course
- Mumbai
Frequent Asked Questions
· Requirements
Candidates who are not graduates of the University of Mumbai or those who have not passed the S.S.C. / H.S.C. of the Pune Board or any other statutory examining body must apply for an eligibility certificate from the Eligibility section, University of Mumbai, Ambedkar Bhavan, Vidyanagari, Kalina, Mumbai-400098. Application for eligibility certificate must be accompanied by the Original Certificate and Mark Sheet from the Institution from where the candidate has graduated.
Course programme
The University of Mumbai offers CONVERSATIONAL COURSE IN GERMAN FOR BEGINNERS (Part time) to its students. The course structure for it is as follows:
This course is structured to introduce basic German vocabulary, phrases and day to day conversational skills.
The course aims to impart quality education in all fields: German language, literature, culture, translation & intercultural studies. The academic curriculum of advanced courses is supplemented by numerous seminars on literature, intercultural hermeneutics, linguistics, translation, philosophy, aesthetics etc.


text:
Join the Thirsty Brothers, along with The Volunteers Band, Monday, July 3rd. This annual event takes place outdoors, overlooking beautiful Harrisville Pond. Take a swim, enjoy great music, and then settle in for a wonderful fireworks show! Music starts around 6pm.
The Thirsty Brothers
Upcoming Shows
Upcoming Shows:
May 5th - Cinco DeMayo - Tap 25, Stowe, VT.
May 28th - Private Party - Marlborough, NH.
July 3rd - Sunset Beach Fireworks, 6pm, Harrisville, NH.
July 5th - Oxbow Park - 5:30-7:30, Morrisville, VT.
July 7th - Stowe Balloon Fest, Stowe, VT.
July 8th - Balloon Fest, StoweFlake Resort, VT.
July 22nd - Bridgton Highlands Country Club, Bridgton, ME.
August 5th - Private Party - Dublin, NH.
August 19th - Private Party - Walcott, VT.
Thursday, June 29, 2017
Wednesday, April 19, 2017
The Cactus Cafe - Stowe Vermont
The Brothers have been playing the Cinco De Mayo party at the Cactus Cafe (Stowe VT), in one form or another, for over 15 years! We were scheduled to play again this year but unfortunately the Cactus Cafe will be closing on April 29th. We are thankful to all of the people over the years that made Cinco such a blast! Special thanks to Monique and Doehne for sticking with us and allowing us to be part of such a great tradition for so many years! We will miss it, thankfully we have a decade and a half of great memories to carry with us.
Brother Jim will be playing at the final party on April 29th! Head on down to see all of the happy faces, hear great music, and thank the folks at the Cactus.
"Play something good!"
Wednesday, January 18, 2017
Looking Forward...
The Thirsty Brothers will be playing at the Oxbow Park in Morrisville, VT. for the first time this summer. Join us, Wednesday, July 5th.
Looking Back...
Happy New Year!
The Thirsty Brothers wish you a very Happy New Year!
We look forward to seeing you in 2017!
We look forward to seeing you in 2017!
Saturday, November 26, 2016
Happy Holidays from The Thirsty Brothers!
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text:
Patty's Industrial Hygiene, 4-Volume Set, 6th Edition
2654 pages
December 2010
US $905.00 Add to Cart
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Patty's Industrial Hygiene, 6th Edition, 4-Volume Set
"Patty's…the name has a golden reputation associated with it." Harry Elston, Editor of Journal of Chemical Health and Safety.
The 6th Edition of the cornerstone reference work on occupational health and toxicology is now published by Wiley. Patty's Industrial Hygiene, 6th Edition, 4-Volume Set (December 2010) updates its comprehensive coverage and adds chapters to reflect the changing and expanding field of industrial hygiene.
Industrial hygiene is the science of evaluating and controlling workplace conditions that may cause workers' injury or illness. It is an interdisciplinary field that integrates chemistry, engineering, toxicology, medicine, and occupational health. Liability issues and the prospect of litigation loom large as motivating factors for regulatory compliance by corporate employers.
Now over six decades in print, Patty's Industrial Hygiene, 6th Edition has evolved into a standard reference for chemists, engineers, toxicologists, and occupational safety personnel. Since the 5th edition was published, the field of industrial hygiene has changed with personnel often self-employed, working for multinational firms, or at small consulting firms. As the working environment has changed and expanded, so have the types of information and resources required.
Patty's Industrial Hygiene, 6th Edition includes, in four volumes, new information and reliable resources to prepare for natural disasters, exposures to biological agents and potential acts of terrorism. There are new chapters on Homeland Security, Nanomaterials, Chemical Toxicants, Assessment of Contaminants, Recognition and Evaluation of Physical Agents, Ergonomics, Bioaerosols, International Regulations, Hospital Safety, Fire Safety, and Emergency Disaster Response.
Patty's Industrial Hygiene, 6th Edition is the standard work for a wide range of professionals including industrial hygienists in consulting and industry, chemical hygiene officers, toxicologists and occupational medicine physicians, occupational/ environmental health and safety professionals and managers, and health and safety regulators. It is also a required resource for industrial hygiene academic programs.


text:
Furgerson's Garage
ReScore Reviews™ (3)
99% Would Recommend
Latest Review 5 days ago
Review for Furgerson's Garage
Dwight N. on 06/27/2016
"Friendly & Reliable Auto Repair"
Recently I have taken our vehicles to Furgerson's Garage for a variety of repairs and smog service. The office staff is helpful and friendly. The service has been done in the time promised. I'd recommend brining your car here.
Vehicle: Ford Escape
Service Date: 06/24/2016
Review Created: 06/27/2016 02:56 PM


text:
Talk about angry customers. If you thought having to tell shoppers that they missed out on the latest and greatest dress deals, imagine having to tell shoppers who happen to be vampires that the blood is running out, and they all have to guzzle more coffee than the red stuff as a result. Check out a new clip from "Daybreakers" that addresses just that topic. In a word, it ain't pretty. In fact, it's pretty downright bloody and very human of them, which I suppose is the point.
In the year 2019, a plague has transformed most every human into vampires. Faced with a dwindling blood supply, the fractured dominant race plots their survival; meanwhile, a researcher works with a covert band of vamps on a way to save humankind.
Starring Ethan Hawke, Willem Dafo, Isabel Lucas, Sam Neill, Claudia Karva, Jay Laga'ai, Emma Randal, Vince Colosimo, Michelle Atkinson, Michael Dorman, and written and directed by the brothers Spierig.
Break on through January 8, 2010.