Effective improvement of the carbon-based CsPbI2Br perovskite solar cells through additive and interface strategies

All-inorganic CsPbI2Br perovskite solar cells have received extensive attention due to its marvellous performance. However, the non-radiative recombination caused by the defects at the CsPbI2Br usually limits the performance of the corresponding perovskite solar cells. To address this issue, in this paper, acrylic acid (AA) was introduced to react with PbI2 to improve the quality of the CsPbI2Br film by ameliorating the crystallinity and reducing detrimental trap states. Besides, a conductive carbon skeleton calcinating the hydrogels was introduced to passivate the CsPbI2Br layer showing excellent electrochemical performance. The abundant heteroatoms and functional groups in the carbon framework can play a role in passivating CsPbI2Br defects. The optimized photoelectric conversion efficiency (PCE) of the carbon-based CsPbI2Br perovskite solar cells (C-PSCs) reach 12.71%, which was higher than the pristine cells. In addition, the nonencapsulated modified CsPbI2Br-based device remains 93% of its initial efficiency after 20 days. This work provides a straightforward method to improve the performance of the all-inorganic CsPbI2Br-based C-PSCs.