Multiple-Color-Generating Cu(In,Ga)(S,Se)2 Thin-Film Solar Cells via Dichroic Film Incorporation for Power-Generating Window Applications

Abstract

There are four prerequisites when applying all types of thinl-film solar cells to power-generating window photovoltaics (PVs): high power-generation efficiency, longevity and high durability, semitransparency or partial-light transmittance, and colorful and aesthetic value. Solid-type thin-film Cu(In,Ga)S-2 (CIGS) or Cu(ln,Ga)(S,Se)(2) (CIGS-Se) PVs nearly meet the first two,criteria, making them promising candidates for power-generating window applications if they can transmit light to some degree and generate color with good aesthetic value. In this study, the : mechanical scribing process removes 10% of the window CIGSSe thin-Alin solar cell with vacant line patterns to provide a partial4ight-transmitting CIGSSe PV module to meet the third requirement. The last concept of creating distinct colors could be met by the addition of reflectance colors of one-dimensional (1D) photonic crystal (PC) dichroic film on the black part of a partial-light-transmitting CIGSSe PV module. Beautiful violets and blues were created on the cover glass of a black 'CIGSSe PV module via the addition of 1D PC blue-Mirror yellow-pass dichroic film to improve the aesthetic value of the outside appearance. As a general result from the low external quantum efficiency (EQE) and absorption of CIGSSe PVs below a wavelength of 400 nm, the harvesting efficiency and short-circuit photocurrent of CIGSSe PVs were reduced by only similar to 10% without reducing the open-circuit voltage-(V-oc) because of the reduced overlap between the absorption spectrum of CIGSSe PV and the reflectance spectrum of the 1D PC blue-mirror yellow-pass dichroic film. The combined technology of partial-vacancy-scribed CIGSSe PV modules and blue ID PC dichroic film can provide a simple strategy to be applied to violet/blue power-generating window applications, as such a strategy can improve the transparency and aesthetic value without significantly sacrificing the harvesting efficiency of the CIGSSe PV modules.