Despite the rapid progress in perovskite light-emitting diodes (PeLEDs), achieving high stability remains an outstanding challenge. PeLEDs produce heat during operation, raising the temperatures, which accelerate device degradation. To determine the PeLED temperatures, a very limited number of techniques represented by infrared thermal imaging (ITI) are employed. However, ITI mainly characterizes the temperature of the exposed top surface of the device, leaving the actual temperature in the perovskite emissive layer unresolved. Here, we address this challenge by directly characterizing the temperature of the perovskite layer via an electroluminescence (EL) analysis. Model PeLEDs emitting in the near-infrared (FAPbI₃), red (FA_0.5Cs_0.5PbI₂Br) and green (FA_0.6Cs_0.7PbBr₃) spectral regions are tested. Urbach energies related to thermal broadening are obtained from the EL spectra, enabling real-time tracking of the perovskite emissive layer temperature under working conditions. Our results demonstrate that the EL analysis is a simple and effective method for the operando temperature characterization of PeLEDs.

中文翻译：

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通过电致发光对钙钛矿 LED 进行温度表征


尽管钙钛矿发光二极管 （PeLED） 取得了快速进展，但实现高稳定性仍然是一个突出的挑战。PeLED 在工作过程中会产生热量，导致温度升高，从而加速器件退化。为了确定 PeLED 温度，采用了以红外热成像 （ITI） 为代表的非常有限的技术。然而，ITI 主要表征器件裸露顶面的温度，而钙钛矿发射层中的实际温度则未得到解决。在这里，我们通过电致发光 （EL） 分析直接表征钙钛矿层的温度来应对这一挑战。测试了在近红外 （FAPbI₃）、红色 （FA_0.5Cs_0.5PbI₂Br） 和绿色 （FA_0.6Cs_0.7PbBr₃） 光谱区域中发射的模型 PeLED。从 EL 光谱中获得与热展宽相关的 Urbach 能量，从而能够在工作条件下实时跟踪钙钛矿发射层温度。我们的结果表明，EL 分析是一种简单有效的 PeLED 原位温度表征方法。