Strain-Engineered PbS Quantum Dot Solar Cells with Suppressed Trap States and Enhanced Performance.

Li, Jing; Ding, Xiaobo; Dong, Wei; Luo, Zhao; Wang, Jianxun; Hua, Yulu; Song, Ziqi; Miao, Zeyu et al. · Nano Lett · 2025

basic_science · Level V

Where this comes from

Abstract

Surface strain in quantum dot (QD) films, while not a defect itself, can distort the local lattice environment and promote the formation of electronic trap states, ultimately limiting charge transport and device performance. Here, we introduce a strain-modulation strategy using guanidinium iodide (GAI) to partially disrupt the continuous PbI<sub>2</sub>-based ligand shell on PbS QDs. By relaxing the interfacial lattice strain by 53%, strain-induced trap states are suppressed, improving carrier transport in QD films. Solar cells based on these optimized films achieve a power conversion efficiency of 14.2%, compared to 12.5% in control devices. This study underscores the critical role of surface strain as a hidden regulator of electronic quality in QD solids and offers a new avenue for interfacial strain management in solution-processed optoelectronics.