Managing Crystallization and Shallow Defect via Infrared Rapid Thermal Annealing Enables High‐Efficiency Sb ₂ S ₃ Solar Cells

Antimony sulfide (Sb₂S₃) has emerged as a promising thin-film photovoltaic absorber material due to its suitable bandgap and high absorption coefficient. However, the fabrication of Sb₂S₃ films with high crystallinity and low defect density remains a critical challenge in current research. Here, we propose an infrared rapid thermal annealing (IRTA) strategy to regulate crystallization dynamics and defect passivation of Sb₂S₃ absorber layers. Unlike conventional interfacial seed formation, IRTA induces homogeneous nucleation within the amorphous Sb₂S₃ matrix. This significantly reduces the number of crystal seeds, thus obtaining an absorber layer with high crystallinity and fewer grain boundaries. Additionally, the diffusion of Cd into the Sb₂S₃ lattice is remarkably enhanced, which promotes the formation of favorable Cd_Sb shallow-level defects. Solar cells incorporating the optimized Sb₂S₃ films achieve a power conversion efficiency of 8.01%. This work elucidates the pivotal role of IRTA in modulating the material characteristics of Sb₂S₃ and provides a feasible pathway for the fabrication of high-performance Sb₂S₃ optoelectronic devices.