Some of Keszler’s early work shows the importance of his research in material science for application purposes. For example, in 2002, he worked on thin-film electroluminescent devices which display high definition monochromic color outputs, and developing them to display a full range of color. They specifically focused on phosphor ZnGaS:Mn and strontium sulfide codoped with copper and potassium powders which was observed to have identical emission properties as thin films. Essentially by codoping, the band gap length of a material can be tuned so that the color of the light can be adjusted. The light itself is emitted when excited electrons in the conduction band fall back down to the valence band. By manipulating the properties of crystal and defect chemistry, any color can be portrayed for display.
Keszler has also developed a convenient method for solid synthesis. In 2001, he demonstrated a hydrothermal dehydration technique of precipitates which avoids formation of amorphous products that are created through the conventional drying process of heating. Through this method, he showed the formation of ZnSiO and SnSiO. This technique has allowed for development of materials such as powders, thin films, and luminescent materials.
In 2000, Douglas Keszler and his colleagues worked with non-linear optical materials such as CaGdO(BO)(GdCOB). They measured the Raman spectra of CaGdO(BO)(GdCOB) which was grown using the Czochralski method. This experiment was done to ultimately understand the spectroscopic features of Yb and Nd by analyzing vibrations of two different types of (BO) groups.