Synergistic anti-solvent engineering with piperizium salts for highly efficient inverted perovskite solar cells exceeding 25 %

Trap-assisted non-radiative recombination in the perovskite (PVK) film is a primary limitation in further enhancing the performance of inverted perovskite solar cells (PSCs). Herein, an effective anti-solvent additive strategy is proposed, employing 1-(2-Methoxyphenyl)piperazine hydrochloride (2MPCl) as a multifunctional anti-solvent additive to passivate defects in PVK. The introduction of 2MPCl effectively passivate Pb²⁺ and halide vacancies through ion bonds and hydrogen bonds, thereby obtaining high-quality PVK films. Besides, the multifunctional 2MPCl can effectively modulate the energy level structure of PVK, resulting in a more n-type PVK surface, thereby facilitating electron transfer between PVK and PCBM. Consequently, the optimization of energy levels and suppression of trap-assisted recombination elevate the efficiency of devices with 2MPCl to 25.02 %, with significantly enhanced stability compared to control devices. This novel anti-solvent additive strategy aims to address the challenge of trap-assisted non-radiative recombination in PVK film, which is important for enhancing the performance of inverted PSCs.