Bi<sub>2</sub>S<sub>3</sub> Nanocrystal–CsPbBr<sub>3</sub> Hybrid Absorber Enables\nDurable and Efficient Carbon-Based\nPerovskite Solar Cells

The high-quality absorber with improved light absorption\nability\nand crystallinity plays a critical role in enhancing the photovoltaic\nperformance of CsPbBr<sub>3</sub>-based solar cells. This work developed\na Bi<sub>2</sub>S<sub>3</sub> nanocrystal–CsPbBr<sub>3</sub> hybrid absorber to improve the photovoltaic performance of perovskite\nsolar cells (PSCs) by taking advantages of both CsPbBr<sub>3</sub> and Bi<sub>2</sub>S<sub>3</sub>. The as-synthesized Bi<sub>2</sub>S<sub>3</sub> nanocrystals with different structures, including quantum\ndots (QDs) and nanorods (NRs), were applied as the hybridizer of CsPbBr<sub>3</sub> by embedding them into the CsPbBr<sub>3</sub> matrix, respectively,\nwhile the Bi<sub>2</sub>S<sub>3</sub> QDs and NRs were prepared just\nby adjusting the synthesized times. Ultimately, the CsPbBr<sub>3</sub>–Bi<sub>2</sub>S<sub>3</sub> NR hybrid absorber enables carbon-based\nPSCs (C-PSCs) to achieve a champion power conversion efficiency (PCE)\nof 9.37%, which presents an improvement of 19.7% compared with the\nPCE of the device based on the pristine CsPbBr<sub>3</sub> absorber.\nThe improved photovoltaic performance originated from the enhanced\ncrystallinity, reduced surface defects, broadened light response region\nin the hybrid absorber, and enhanced carrier separation/transport\nprocess in the device. This study provides valuable guidance for the\ndesign and assembly of nanocrystal–perovskite hybrid absorbers\nto improve the photovoltaic performance of CsPbBr<sub>3</sub>-based\nsolar cells.