Improving Performance of Perovskite Solar Cells by Reducing Energetic Disorder of Hole Transport Polymer

Polymer hole transport materials offer significant efficiency and stability advantages for p-i-n perovskite solar cells. However, the energetic disorder of amorphous polymer hole transport materials not only limits carrier transport but also impedes contact between the polymer and perovskite, hindering the formation of high crystalline quality perovskites. Herein, a novel low energetic disordered polymer hole transport material, PF8ICz, featuring an indeno[3,2-b]carbazole unit with extended pi-conjugation is designed and synthesized. Analyses based on both theoretical calculations and experimental validation highlight the advantages of PF8ICz as a low energetic disorder polymer hole transport material for perovskite solar cells, including improved carrier transport, enhanced perovskite affinity/passivation, and optimized energy levels. Perovskite films formed atop PF8ICz exhibit superior crystalline quality and improved exciton dynamics. PF8ICz-based perovskite solar cells achieve remarkable power efficiency (PCE > 25.4%) and outstanding stability (retaining 96.2% and 95.0% of their PCE under the ISOS-D-3 and ISOS-L-3 protocols over 1000 h, respectively). These findings underscore the importance of rational design of hole transport materials, contributing to the development of high-performance, stable perovskite solar cells for sustainable energy solutions.