Controlling Tin Halide Perovskite Oxidation Dynamics in Solution for Perovskite Optoelectronic Devices

Abstract

AbstractAs a leading contender to replace lead halide perovskites, tin‐based perovskites have demonstrated ever increasing performance in solar cells and light‐emitting diodes (LEDs). They tend to be processed with dimethyl sulfoxide (DMSO) solvent, which has been identified as a major contributor to the Sn(II) oxidation during film fabrication, posing a challenge to the further improvement of Sn‐based perovskites. Herein, we use NMR spectroscopy to investigate the kinetics of the oxidation of SnI2, revealing that autoamplification takes place, accelerating the oxidation as the reaction progresses. We propose a mechanism consistent with these observations involving water participation and HI generation. Building upon these insights, we have developed low‐temperature Sn‐based perovskite LEDs (PeLEDs) processed at 60 °C, achieving enhanced external quantum efficiencies (EQEs). Our research underscores the substantial potential of low‐temperature DMSO solvent processes and DMSO‐free solvent systems for fabricating oxidation‐free Sn‐based perovskites, shaping the future direction in processing Sn‐containing perovskite materials and optoelectronic devices.