Multistrategy Toward Highly Efficient and Stable CsPbI2Br Perovskite Solar Cells Based on Dopant-Free Poly(3-Hexylthiophene)

All-inorganic perovskites have attracted substantial interest due to their outstanding thermal stability. However, the device performance is still inferior to the typical organic-inorganic counterparts because of the unsatisfying phase stability and defects of the inorganic perovskite films. Herein, a multistrategy to optimize CsPbI2Br perovskite solar cells (PSCs) based on dopant-free poly(3-hexylthiophene) (P3HT) by applying thienylmethylamine acetate additive to enhance the alpha phase stability and passivate the bulk defects of CsPbI2Br perovskite is successfully demonstrated, followed by implementing BTCIC-4Cl interlayer at CsPbI2Br/P3HT interface, which can coordinate with both perovskite and P3HT to suppress the surface defects and promote the hole transport. Benefitting from these, a champion power conversion efficiency (PCE) of 16.3% is achieved, and the unencapsulated optimized device can retain 97% of the initial PCE after aging under N-2 atmosphere at 85 degrees C for 530 h. This work opens up a new era of multistrategy for improving performance and stability of CsPbI2Br PSCs based on dopant-free hole transport layer.

Automated summary

The study demonstrated a multi-strategy approach to optimize CsPbI2Br perovskite solar cells, achieving high efficiency and long-term stability by enhancing phase stability and passivating film defects.