Approach to Transparent Photovoltaics Based on Wide Band Gap Sb₂S₃Absorber Layers and Optics-Based Device Optimization

Numerous methods have been employed for utilizing inorganic thin films to improve the stability of transparent photovoltaics (TPVs). However, the use of these methods was restricted due to limitations involving restricted physical dimensions, complex fabrication processes, visible transparency, and photovoltaic performance. In this study, a novel approach to novel TPVs based on wide band gap inorganic thin-film solar cell devices was first proposed. This approach was based on an Sb2S3 thin-film absorber and the optical optimization of a planar-type solar cell device structure. High-quality and uniformly thick Sb2S3 thin films were deposited via atomic layer deposition (ALD) to produce a high-quality transparent absorber layer for a planar-type transparent thin-film solar cell. To maintain the light transmittance of ALD-Sb2S3 solar cell devices, a flat indium tin oxide (ITO) substrate, a low-temperature-processed ALD TiO2 electron-transport layer (ETL), and an ultrathin Au top electrode were systematically combined with the transparent ALD-Sb2S3 absorber layer. The transparent ALD-Sb2S3 solar cell device showed a power conversion efficiency of 3.44% and an average light transmittance of 13%. These results proposed the technological possibility of using novel inorganic transparent Sb2S3 solar cell devices for transparent applications, such as self-powered transparent displays, high-efficiency tandem solar cells, robust bifacial solar cells, and so on.