Interface Field‐Effect Passivation Enabled by Selectively Extruded Cations for Printable Mesoscopic Perovskite Solar Cells with Improved Performance
Jianhang Qi, Bolun Zhang, Yongming Ma, Xu Dang, Kai Chen, Jiale Liu, Yang Zhou, Anyi Mei, Hongwei Han
Abstract
Mesoporous electron transport layer (ETL) in printable mesoscopic perovskite solar cells (p-MPSCs) enables rapid and selective extraction of photogenerated electrons and facilitates device fabrication without a hole transport layer (HTL). However, the inherent mesoporous architecture introduces abundant interfacial defects that promote undesired non-radiative recombination, limiting the power conversion efficiency (PCE). To address this challenge, an interface field-effect passivation strategy is implemented, leveraging spatially selective cation extrusion. By incorporating tetraphenylphosphonium cations, sterically bulky organic ions that migrate to the perovskite/ETL interface during crystallization, a robust interfacial electrostatic field is introduced. This field simultaneously suppresses the non-radiative recombination by inducing field-effect passivation and enhances the charge extraction through optimizing energy alignment. The synergistic effects yield a PCE enhancement from 19.4% to 21.0%. This work underscores the potential of cation-engineered interfacial fields to improve the performance of HTL-free carbon-electrode perovskite photovoltaics.