Device engineering of Sb2X3 antimony chalcogenide for loss analysis and strategies for maximizing photovoltaic efficiency

Abstract

Antimony chalcogenide (Sb2X3; X=S, Se) is reportedly stable in ambient open-air, abundant, and shows composition-dependent absorption tunability. We simulated the Sb2X3 device utilizing the reported optical and electrical properties to analyze the performance limiting factors and the extent of achievable performance. Initially, we benchmarked the simulated device with the experimental reported device. The VOC-temperature and VOC-illumination characterization of the benchmarked device revealed the contact issue responsible for the VOC deficit. The suboptimal device configuration is a major performance-limiting factor. Contact optimization and conduction band offset optimisation have improved efficiency to 14.86% and 20.45% in Sb2S3 and Sb2Se3, from their experimentally reported values of 7.5% and 9.2% respectively. The optimization of trap-assisted Shockley Read Hall (SRH) recombination in bulk and interface has improved efficiency to 19.43% and 26.13% in Sb2S3 and Sb2Se3, respectively. When extrinsic factors are optimised, such as resistance losses (series resistance as high as 2 Ωcm2 and shunt resistance as low as 1000 Ωcm2), efficiency increased to 20.03% and 26.82% for Sb2S3 and Sb2Se3, respectively. Finally, with ideal intrinsic recombination parameters (radiative and Auger recombination), efficiency improved to theoretical limits (corresponding to their band gap). The study highlights the possibility of immediate gain upon contact passivation in Sb2S3 and Sb2Se3.