Rapid Thermal-Driven Crystal Growth and Defect Suppression in Antimony Selenide Thin Film for Efficient Solar Cells

Antimony selenide (Sb₂Se₃) has demonstrated considerable potential and advancement as a light-absorbing material for thin-film solar cells owing to its exceptional optoelectronic characteristics. However, challenges persist in the crystal growth, particularly regarding the nucleation mechanism during pre-selenization process for Sb₂Se₃. The defects originating from this process significantly impact the quality of the absorber layer, leading to the degradation in the power conversion efficiency (PCE) of the device. Herein, the evolution of pre-selenization using rapid thermal processing (RTP) on the crystallization quality of Sb₂Se₃ film is systematically investigated. By optimizing the initial nucleation process during pre-selenization, resulting in a reduction of grain boundaries and nucleation centers, the Sb₂Se₃ thin films demonstrate enhanced crystallinity and pinholes-free morphology. It is found that the improved quality of the grain interior and interfaces of the Sb₂Se₃ absorber can mitigate intrinsic defects within the bulk layer, and passivate interfacial defect recombination. As a result, the short circuit current density (J_SC) is elevated to 28.97 mA cm^-2, and a competitive efficiency of 9.03% is achieved in Sb₂Se₃ device. This study provides comprehensive insight into the process of crystal growth and the mechanism for defect suppression, which holds guiding significance for advancing photovoltaic performance.