Radical polymeric p-doping and grain modulation for stable, efficient perovskite solar modules

High-quality perovskite light harvesters and robust organic hole extraction layers are essential for achieving high-performing perovskite solar cells (PSCs). We introduce a phosphonic acid???functionalized fullerene derivative in mixed-cation perovskites as a grain boundary modulator to consolidate the crystal structure, which enhances the tolerance of the film against illumination, heat, and moisture. We also developed a redox-active radical polymer, poly(oxoammonium salt), that can effectively p-dope the hole-transporting material by hole injection and that also mitigates lithium ion diffusion. Power conversion efficiencies of 23.5% for 1-square-centimeter mixed???cation-anion PSCs and 21.4% for 17.1-square-centimeter minimodules were achieved. The PSCs retained 95.5% of their initial efficiencies after 3265 hours at maximum power point tracking under continuous 1-sun illumination at 70?? ?? 5??C.

Automated summary

High-quality perovskite light harvesters and robust organic hole extraction layers are necessary for high-performing perovskite solar cells (PSCs). The introduction of a phosphonic acid-functionalized fullerene derivative as a grain boundary modulator in mixed-cation perovskites enhances the film's tolerance against illumination, heat, and moisture. Additionally, a redox-active radical polymer, poly(oxoammonium salt), effectively p-dopes the hole-transporting material and reduces lithium ion diffusion. PSCs with power conversion efficiencies of 23.5% for 1-square-centimeter mixed-cation-anion PSCs and 21.4% for 17.1-square-centimeter minimodules were achieved, with a 95.5% retention of initial efficiencies after 3265 hours of continuous 1-sun illumination at 70±5℃.