RESEARCH ARTICLE

Improved vacuum‑evaporated blue perovskite light‑emitting diodes with phenethylammonium chloride and guanidinium bromide

Liang Sun, Xiping He, Zhiyuan He, Feihu Zhang, Chencheng Peng, Ben Chen, Runda Guo, Lei Wang

Front. Optoelectron., 2025, 18(2): 5.https://doi.org/10.1007/s12200-025-00152-8

Abstract：Metal halide perovskites have become one of the most competitive new-generation optoelectronic materials due to their excellent optoelectronic properties. Vacuum evaporation can produce high-purity and large-area films, leading to the wide application of this method in the semiconductor industry and optoelectronics field. However, the electroluminescent performance of vacuum-evaporated perovskite light-emitting diodes (PeLEDs) still lags behind those counterparts fabricated by solution methods. Herein, based on vacuum evaporation, 3D perovskite films are obtained by three-source co-evaporation. Considering the unique quantum well structure of quasi-2D perovskite can significantly enhance the exciton binding energy and improve the radiative recombination rate, leading to a high photoluminescence quantum yield (PLQY). Subsequently, the highly stable and low-defect-density quasi-2D perovskite is introduced into 3D perovskite films through post-treatment with phenethylammonium chloride (PEACl). To minimize the degradation of film quality caused by PEACl treatment, a layer of guanidinium bromide (GABr) is vacuum evaporated on top of PEACl treatment to further improve the quality of emitting layer. Finally, under the synergistic post-processing modification of PEACl and GABr, blue PeLEDs with a maximum external quantum efficiency (EQE) of 6.09% and a maximum brightness of 1325 cd/m2 are successfully obtained. This work deepens the understanding of 2D/3D heterojunctions and provides a new approach to construct PeLEDs with high performance.

研究背景

金属卤化物钙钛矿因其优异的光电性能而成为新一代光电材料的有力竞争者。真空蒸发法能够制备高纯度、大面积薄膜，广泛应用于半导体和光电领域。然而，真空蒸发法制备的钙钛矿发光二极管（PeLEDs）的电致发光性能仍落后于溶液法制备的器件。尤其是蓝光PeLEDs的研究明显滞后，其在制备过程中存在的缺陷密度和晶体质量问题导致器件性能下降，限制了其发展和应用。

主要内容

本文通过真空蒸发法结合后处理策略，成功制备了高性能的蓝光钙钛矿发光二极管。研究团队首先通过三源共蒸发法制备三维钙钛矿薄膜，然后利用苯乙基氯化胺（PEACl）后处理引入准二维钙钛矿，形成2D/3D异质结结构。为减少PEACl处理对膜质量的负面影响，进一步在表面蒸发一层胍基氢溴酸盐（GABr），以改善发光层的质量。

创新点

采用PEACl和GABr的协同后处理策略，成功构建了2D/3D异质结，并显著提高了钙钛矿层的性能。这种策略不仅提高了器件的电致发光效率，还增强了其稳定性和湿度耐受性。

方法

研究中使用了多种表征手段，包括吸收光谱、光致发光（PL）光谱、X射线衍射（XRD）、扫描电子显微镜（SEM）、原子力显微镜（AFM）、X射线光电子能谱（XPS）、时间分辨光致发光（TRPL）和空间电荷限制电流（SCLC）测试等，系统研究了PEACl和GABr处理对钙钛矿薄膜缺陷密度和载流子寿命的影响，并揭示了其作用机制。

结果

经过PEACl和GABr后处理的蓝光PeLEDs实现了最大外量子效率（EQE）6.09%和最大亮度1325 cd/m²。与未处理的器件相比，后处理显著提高了器件的性能和稳定性。此外，通过接触角测试评估了膜的湿度稳定性，结果表明后处理能够有效提高膜的疏水性，从而增强器件的操作稳定性。