Metallic thin films are also used in plasmonic waveguide designs. Thin-film photovoltaic cells Thin-film technologies are also being developed as a means of substantially reducing the cost of solar cells. The rationale for this is thin-film solar cells are cheaper to manufacture owing to their reduced material costs, energy costs, handling costs and capital costs. This is especially represented in the use of printed electronics (roll-to-roll) processes. Other thin-film technologies, that are still in an early stage of ongoing research or with limited commercial availability, are often classified as emerging or third generation photovoltaic cells and include, organic, dye-sensitized, and polymer solar cells, as well as quantum dot, copper zinc tin sulfide, nanocrystal and perovskite solar cells. Thin-film batteries Thin-film printing technology is being used to apply solid-state lithium polymers to a variety of substrates to create unique batteries for specialized applications. Thin-film batteries can be deposited directly onto chips or chip packages in any shape or size. Flexible batteries can be made by printing onto plastic, thin metal foil, or paper. Thin-film bulk acoustic wave resonators (TFBARs/FBARs) For miniaturising and more precise control of resonance frequency of piezoelectric crystals thin-film bulk acoustic resonators TFBARs/FBARs are developed for oscillators, telecommunication filters and duplexers, and sensor applications. See also Coating Dual-polarisation interferometry Ellipsometry Flexible display Flexible electronics Hydrogenography Kelvin probe force microscope Langmuir–Blodgett film Layer by layer Microfabrication Organic LED Sarfus Thin-film interference Thin-film optics Thin-film solar cell Thin-film bulk acoustic resonator References Further reading Textbooks Historical Artificial materials Materials science Nanotechnology