Unveiling the performance of Sb 2 S 3 solar cells for indoor illumination through device simulation

Abstract Indoor photovoltaics (IPV) are emerging as a key enabling technology for self-powered sensors and portable electronics, yet the development of high-performance absorbers optimized for low-intensity illumination remain limited. In this work, we investigate the suitability of antimony sulfide (Sb 2 S 3 ) for indoor solar energy harvesting using comprehensive device-level simulations performed in SCAPS-1D. The influence of absorber layer thickness and illumination source (warm LED, cool LED, halogen, xenon, fluorescent, incandescent, and AM1.5G sunlight) was systematically analyzed to identify performance-limiting factors and optimal design parameters. Our results show that Sb 2 S 3 exhibits strong potential for indoor environments due to its favorable bandgap (1.7–1.8 eV) and high absorption coefficient, enabling efficient carrier generation under artificial lighting. The simulations shows that in the thickness range 200–2000 nm, an absorber thickness of 400–600 nm yields the highest indoor power conversion efficiency, reaching ∼37.4 % under warm LED illumination, while under AM1.5G conditions the optimal thickness is ∼500 nm with a maximum efficiency of 22.2 %, respectively. The strong sensitivity of efficiency to illumination spectrum underscores the importance of spectral matching in IPV device design. This study establishes the thickness-dependent performance limits of Sb 2 S 3 -based solar cells under realistic indoor lighting and highlights their promise as cost-effective absorbers for next-generation low-light photovoltaic applications.