Conjugated Polymer Turning Grain Boundary Beneficial for Highly Efficient and Stable Perovskite Solar Cells
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초록
내용
The existence of a large number of defects in the grain boundary of polycrystalline metal-halide perovskite films negatively impacts the performance and stability of perovskite solar cells (PSCs). In order to address this issue, our groups report the use of organic cyano-based conjugated polymers composed of benzodithiophene bicyanobenzothiadiazole (PBDT2CNBT). These polymers effectively passivate the defects through the strong interaction between the conjugated polymer and perovskite components. The polymers also construct a favorable energy band bending at the boundary interface between polymer and conjugated polymer, leading to improved charge separation and transport through the grain boundaries. Our groups demonstrate that the addition of PBDT2CNBT to the PSCs results in improved power conversion efficiencies, reaching up to 22.9%, as well as enhanced light, humidity, and thermal stability.