Enhancing the Efficiency of GaSb Photovoltaic Cell Using Thin-Film Multiscale Haze and Radiative Cooling

In this work, a multiscale thin-film membrane of self-aggregated anodized aluminum oxide (AAO) nanowire structure was developed to enhance the efficiency of GaSb photovoltaic (PV) cell using both optical haze and passive radiative-cooling effects in a broad region of the solar spectrum. We controlled, (1) the optical properties of thin-film AAO and (2) the plasmonic-induced perfect absorption/emission by changing packing densities and lengths of AAO nanowires during the anodization and wet etching processes. The AAO nanowire structures provide 98% absorption/emission in the environmental emission/transmission window (8–13 μm), resulting in efficient passive self-cooling and higher-order optical haze transmission up to approximately 98%; privileged characteristics enhance the suppressed PV efficiency due to the unwanted reflection of incident light and excessive heating effects caused by low- and high-energy photons unused by the band gap of the cell. By integrating this thin-film nanowire structure membrane with the front surface of the GaSb cell, we achieved an overall increase in efficiency of 18% in contrast with a bare cell.