PECVD Synthesis of Flexible Optical Coatings for Renewable Energy Applications

The design, fabrication, and evaluation of flexible, multilayer optical coatings deposited by plasma-enhanced chemical vapor deposition at low temperature are demonstrated using hybrid nanolaminates consisting of TiO₂ and silicone (SiO_xC_yH_z) as the high and low refractive index materials, respectively. A broadband anti-reflection coating was designed and deposited onto a variety of substrates including flexible polyethylene terephthalate (PET) and CdTe solar cells which was shown to increase absolute transmission by an average of 3% over 410-850 nm wavelengths and results in a commensurate increase in short circuit current density. An infrared reflector was designed and applied to PET which was found to provide 70% reflectance in the near-IR while maintaining >80% transmittance for visible light. The optical performance of these flexible coatings on PET remained unchanged after automated bend testing, and were shown to be robust with respect to humidity and thermal shock tests. Hybrid TiO₂-silicone nanolaminates fabricated by PECVD are flexible, robust optical coatings. TiO₂ provides UV protection and self-cleaning functionality, while silicone imparts flexibility and durability. The performance of broad band AR coatings and IR reflectors deposited on polyethylene films remain unchanged after automated bend testing, and robust with respect to humidity and thermal shock tests.