Unlocking the Potential of Selenium Solar Cells for Indoor and Tandem Photovoltaics Through Theoretical and Photoelectric Simulations

Abstract

Selenium (Se) solar cells, originators of solid-state photovoltaics, confront issues with bulk defect density and interface energy barriers that impede power conversion efficiency (PCE). Our research tackles these by examining the impact of Se defect states and interface energy levels on photoelectric performance. Through ab initio molecular dynamics (AIMD) simulations, we reveal the crystallization dynamics of Se thin films at varying temperatures, highlighting annealing’s importance in reducing defects. Density functional theory (DFT) calculations have been further used to evaluate the electronic properties affected by Se atoms/clusters and short chains. By merging electrical and optical simulations, we have optimized the device design, boosting PCE to 16.2% under AM1.5 and an impressive 33.12% under 1000 lux indoor lighting—surpassing experimental values by 188% and 127%, respectively. Additionally, the tandem devices maintain comparable power conversion efficiency (23.5%) to state-of-the-art monolithic CIGS cells (23.6%) while achieving a 60% reduction in CIGS absorber thickness. Our study lays a solid theoretical foundation for developing high-performance Se solar cells for indoor energy capture and tandem module use.