Superimposed Sacrificial Texturing to Enhance the Optical Performance in Thin-Film Solar Cells

Abstract

Techniques to facilitate excellent optical yield are required to manufacture high-performing solar cells. In thin-film solar cells, light scattering with the help of textured interfaces increases the absorption path length of photons and reduces the reflection of the photovoltaic active layer. These textures should also facilitate the growth of crack-free thin-film layers, ensuring high efficiency in multijunction devices. This work explores three texturing methods for glass that have the potential to be integrated into solar cells in a superstrate configuration. A detailed study of sacrificial texturing on glass using i-ZnO ((Formula presented.)) and indium-doped tin oxide ((Formula presented.)) is presented. The optical interaction of these textures is correlated to their root-mean-square (RMS) roughness ((Formula presented.)). It is demonstrated that high optical scattering can be achieved for both (Formula presented.) and (Formula presented.) but at different (Formula presented.) regimes. A novel texture with superimposed morphology, named superimposed sacrificial texturing ((Formula presented.)), is created by combining (Formula presented.) and (Formula presented.) through sequential wet etching. The (Formula presented.) exhibits exceptional transmission and light scattering properties. Nanocrystalline silicon (nc-Si:H) single-junction solar cells were fabricated in a superstrate configuration to investigate the impact of these textures on indirect bandgap thin-film solar cells. The efficiency of solar cells on (Formula presented.) is nearly 0.57% and 1.52% (absolute) more than (Formula presented.) and (Formula presented.) solar cells, respectively. By superimposing two textures, solar cells can combine the advantages of enhanced optical performance with high-quality nc-Si:H material growth.