Color Implementation of Cu(In,Ga)Se2 Thin-film Solar Cells with Multilayered Conductive Optical Filters

Traditional photovoltaic (PV) cells and modules exhibit a black color to maximize light absorption and minimize light reflection to achieve high efficiency. However, this monotonous color limits their installation in urban environments where aesthetic harmony is important. Therefore, instead of traditional black-colored PV modules, there is a need for colors that can naturally blend with the surroundings. Multilayer optical filters with interference properties at specific wavelengths are mainly used for color implementation. Multilayer coating is applied on a glass substrate, which is mostly used as PV cover glass. so that the transparent conductive oxide layer itself exhibited both color and excellent electrical conductivity, colorful PV modules can be fabricated without the need for additional components. In this study, the number and thickness of repeated Indium tin oxide (ITO) multilayer films were simulated by the Essential Macleod simulation tool. Next, highly conductive ITO thin films with two different SnO2 compositions were repeatedly deposited to implement red, green, blue, and dark blue color filters. Finally, the conductive optical filters were applied to Cu(In,Ga)Se2 (CIGS) thin-film solar cells, and PV performances were investigated.