(3-Aminopropyl)trimethoxysilane Surface Passivation Improves Perovskite Solar Cell Performance by Reducing Surface Recombination Velocity
Yangwei Shi, Esteban Rojas‐Gatjens, Jian Wang, Justin Pothoof, Rajiv Giridharagopal, Kevin Ho, Fangyuan Jiang, Margherita Taddei, Zhaoqing Yang, Erin M. Sanehira, Michael D. Irwin, Carlos Silva, David S. Ginger
Abstract
We demonstrate reduced surface recombination velocity (SRV) and enhanced power-conversion efficiency (PCE) in mixed-cation mixed-halide perovskite solar cells by using (3-aminopropyl)trimethoxysilane (APTMS) as a surface passivator. We show the APTMS serves to passivate defects at the perovskite surface, while also decoupling the perovskite from detrimental interactions at the C60 interface. We measure a SRV of ∼125 ± 14 cm/s, and a concomitant increase of ∼100 meV in quasi-Fermi level splitting in passivated devices compared to the controls. We use time-resolved photoluminescence and excitation-correlation photoluminescence spectroscopy to show that APTMS passivation effectively suppresses nonradiative recombination. We show that APTMS improves both the fill factor and open-circuit voltage (VOC), increasing VOC from 1.03 V for control devices to 1.09 V for APTMS-passivated devices, and leads to a PCE increase from 15.90% to 18.03%. We attribute the enhanced performance to reduced defect density resulting in suppressed nonradiative recombination and lower SRV at the perovskite/transport layer interface.