Efficient carbon-based CsPbI2Br perovskite solar cells achieved via coordination passivation by CS and CO of 4-(2-thioureido)benzoic acid

Abstract

We introduced 4-(2-thioureido)benzoic acid (TB) into carbon-based CsPbI₂Br solar cells, achieving a power conversion efficiency (PCE) of 13.96%. The SO and CO groups in TB coordinate with the un-coordinated Pb²⁺ at the surface and grain boundaries, forming a cross-linked structure that effectively passivates these defects. Additionally, TB forms a barrier on the CsPbI₂Br surface, enabling the TB-modified CsPbI₂Br solar cells to retain 80.8% of their initial device efficiency after 500 hours of storage at 30% relative humidity.