Efficient Charge Collection Promoted by Interface Passivation Using Amino Acid Toward High Performance Perovskite Solar Cells

Abstract

Interfacial modification of organolead halide perovskites (OHPs) has shown to be a promising strategy to improve the quality of OHPs film. In this work, a bipolar amino acid molecule, L‐Leucine (LL), have been introduced to the anti‐solvent solution to induce the formation methylammonium lead triiodide (MAPbI 3 ) perovskite films. The morphology, crystal structure, and optoelectronic property of perovskite films are systematically studied, where the bipolar LL plays a key role. By employing the LL‐modified perovskite film, the perovskite solar cells (PSCs) are well prepared. Consequently, a 18.2% efficiency was obtained from the champion device, which showed a significant improvement compared to the controlled device with a PCE of 16.1%. Our results demonstrate the crucial role of bipolar feature of interfacial modification agent on the charge transfer at the interface, and provide important interfacial modification concept on efficient PSCs. Moreover, significantly improved stability can be observed from the LL modified devices, benefiting from the effectively trap‐passivation.