Xu Zhaojian, Zhong Xinjue, Hu Tuo, Hu Junnan, Kahn Antoine, Rand Barry P
Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States.
Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States.
J Am Chem Soc. 2024 Dec 11;146(49):33368-33377. doi: 10.1021/jacs.4c08939. Epub 2024 Nov 25.
Halide oxidation plays a fundamental role in halide segregation and the degradation of halide perovskites, yet quantitative measurement of halide oxidation in solid-state perovskite samples remains challenging. Herein, we demonstrate that in situ opto-gravimetric measurements based on a quartz crystal microbalance can quantify the photolysis kinetics of solid-state perovskites. By investigating a series of mixed bromide/iodide perovskites with varying halide ratios, we demonstrate identical compositional thresholds ( ∼ 0.4 in the CsPb(BrI) system) for iodide oxidation, light-induced halide segregation, and photolysis. Our findings reveal the correlation between these light-induced instabilities and unambiguously explain the photolysis mechanism of mixed-halide perovskites. We also show that photolysis renders the perovskite film more -type without involving lead reduction. This study introduces a powerful methodology for quantitatively analyzing the mass loss kinetics of halide perovskites under both practical operational and accelerated aging conditions, offering deeper insights into the mechanisms of perovskite degradation.
卤化物氧化在卤化物分离和卤化物钙钛矿的降解过程中起着至关重要的作用，然而，对固态钙钛矿样品中的卤化物氧化进行定量测量仍然具有挑战性。在此，我们证明基于石英晶体微天平的原位光致重量测量能够量化固态钙钛矿的光解动力学。通过研究一系列具有不同卤化物比例的混合溴化物/碘化物钙钛矿，我们证明了碘化物氧化、光致卤化物分离和光解在组成上具有相同的阈值（在CsPb(BrI)体系中约为0.4）。我们的研究结果揭示了这些光致不稳定性之间的相关性，并明确解释了混合卤化物钙钛矿的光解机制。我们还表明，光解使钙钛矿薄膜更呈n型，且不涉及铅的还原。本研究引入了一种强大的方法，用于在实际操作和加速老化条件下定量分析卤化物钙钛矿的质量损失动力学，为深入了解钙钛矿降解机制提供了更多见解。
