Electronic Distribution Tuning of Passivators Enables High-Efficiency and Stable Perovskite Solar Cells

Abstract

Interfacial defects and energy level mismatch in perovskite solar cells (PSCs) severely limit their efficiency and stability. Small-molecule passivators show great potential in addressing interfacial issues, but how electronic effects influence the performance of PSCs by modulating the electrostatic potential distribution of the entire molecule and its functional groups remains unclear. Herein, we introduced different benzylamine derivatives and found that they can all react with the formamidinium cation (FA⁺). Compared to 4-methoxybenzylamine (PMBA) and benzylamine (BA), 4-trifluoromethylbenzylamine (TFMBA) has a lower proton transfer energy barrier, facilitating the formation of TFMBAFA⁺. Compared to PMBAFA⁺ and BAFA⁺, TFMBAFA⁺ forms stronger hydrogen bonds with I^– better stabilizing the perovskite structure; simultaneously, its increased dipole moment promotes energy level alignment and charge carrier extraction. The introduction of the passivators reduced interfacial non-radiative recombination. Finally, TFMBA-modified devices (0.09 cm²) achieved an optimal power conversion efficiency (PCE) of 25.52%, while large-area devices (active area of 23.4 cm²) also attained a PCE of 20.44%. Under continuous illumination in N₂ atmosphere for 1300 h and dark storage at 60 °C, the devices retained 83% and 80% of their initial PCE, respectively.

Keywords

Electronic effect / Proton transfer / Hydrogen bond / Energylevel matching / Interfacial non-radiative recombination / Benzylamine derivatives / Passivator / Perovskite solar cells

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2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH