Improved Pore-Filling and Passivation of Defects in Hole-Conductor-Free, Fully Printable Mesoscopic Perovskite Solar Cells Based on d-Sorbitol Hexaacetate-Modified MAPbI3.

For hole-conductor-free, fully printable mesoscopic perovskite solar cells (MPSCs), it is difficult to achieve free and efficient diffusion of perovskite precursors in micron-scale porous structures. Thus, the wettability of the perovskite precursor is one of the most crucial factors that determine the performance of MPSCs. Here, d-sorbitol hexaacetate (DSHA) is introduced as an additive for fabricating hole-conductor-free, fully printable MPSCs based on methylammonium lead iodide (MAPbI3). The fabricated MPSCs exhibited an efficiency of 14.33%. Moreover, the influence of DSHA on the optical properties, morphology, and filling of perovskite in the MPSCs has been systematically investigated. The results revealed that DSHA effectively optimized the morphology, improved the pore-filling, and passivated the defects of perovskite films. Remarkably, the unencapsulated MPSCs retained 93% of their original power-conversion efficiency (PCE) after 45 days of storage in air with humidity of 50 ± 5%.