Sulfur Vacancies Limit the Open-Circuit Voltage of Sb<sub>2</sub>S<sub>3</sub> Solar Cells
Xinwei Wang, Seán R. Kavanagh, Aron Walsh
Abstract
High Resolution Image Download MS PowerPoint Slide Antimony sulfide (Sb 2 S 3 ) is a promising candidate as an absorber layer for single-junction solar cells and the top subcell in tandem solar cells. However, the power conversion efficiency of Sb 2 S 3 -based solar cells has remained stagnant over the past decade, largely due to trap-assisted nonradiative recombination. Here we assess the trap-limited conversion efficiency of Sb 2 S 3 by investigating nonradiative carrier capture rates for intrinsic point defects using first-principles calculations and Sah–Shockley statistics. Our results show that sulfur vacancies act as effective recombination centers, limiting the maximum light-to-electricity efficiency of Sb 2 S 3 to 16%. The equilibrium concentrations of sulfur vacancies remain relatively high, regardless of growth conditions, indicating the intrinsic limitations imposed by these vacancies on the performance of Sb 2 S 3 .