With the help of DOE funding, Pixelligent Technologies is partnering with OLED panel manufacturer OLEDWorks to accelerate the commercial viability of OLED lighting by improving the extraction efficiency of OLED panels using Pixelligent’s existing PixClear® technology. Generally, only 20–30% of the light in an OLED panel is extracted. PixClear uses zirconia nanocrystals to create nanocomposite (polymers mixed with nanocrystals) structures that have a high refractive index and thus allow more light to escape into the surrounding air. The fact that the nanocrystals are well dispersed — which means they don’t clump together — allows for high clarity, good shelf life, low viscosity, and the manufacturing of uniform and consistent light-extraction structures.
Pixelligent’s nanocrystal extraction layers are compatible with many polymers, which gives them flexibility for use in the manufacturing of OLED panels. The nanocrystals can be combined with different polymer systems to create solution-processable materials that can be used to manufacture transparent, high-refractive-index (HRI) nanocomposites that are compatible with existing high-quality, low-cost manufacturing processes. DOE funding is helping Pixelligent do this, as well as investigate the addition of scatterers to these HRI nanocomposites, which will increase the light output even further.
Initial results are promising, with OLED panel lighting efficiency gains of 100%. Another advantage of Pixelligent’s nanocomposite technology is that it allows for the creation of more advanced structures that can further improve performance. For example, Pixelligent is targeting even greater efficiency through a second DOE-funded project, by creating composites with a graded refractive index, which reduces the amount of light that gets trapped as it transitions through the panel by reducing Fresnel reflection at the interface with the substrate. The PixClear technology also holds promise for other applications, such as displays. (September 2016)
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