基于氯源优化的准二维蓝光钙钛矿发光二极管

Chlorine Source Optimization for Blue Quasi-2D Perovskite Light-Emitting Diode

摘要: 金属卤化物钙钛矿发光二极管(PeLED)因其优异的光电特性引起了研究者们的广泛关注。但是蓝光器件的性能较其他光色仍相对滞后，限制了其全彩显示应用。本文通过比较两种不同氯源对准二维天蓝光PeLED性能的影响，并结合添加剂工程，实现了天蓝光PeLED的制备。首先，以无机盐PbCl₂作为氯源，调控PbBr₂/PbCl₂的摩尔比例，使电致发光(EL)光谱由512 nm蓝移至496 nm，虽然继续增加PbCl₂比例光色可以进一步蓝移，但是器件效率太差无法得到有效性能数据。由于PbCl₂在DMSO溶剂中溶解性差，导致薄膜成核过程不受控制并引发了严重的非辐射复合，器件的外量子效率(EQE)由2.06%急剧下降至0.93%。作为对比，我们使用溶解性更好的邻氟苯乙基氯化胺(o-F-PEACl)有机间隔层配体代替无机盐PbCl₂作为氯源，器件的EL光谱由512 nm蓝移至492 nm，器件的最大EQE由2.06%提升至2.83%。这一结果表明，采用溶解性更好的有机氯源可以有效抑制非辐射复合，在实现光谱蓝移的同时提升器件效率。在此基础上，进一步引入二苯(甲氧基甲基)氧化膦(MMPO)添加剂，通过配位作用钝化卤素空位缺陷，有效抑制非辐射复合，器件最大EQE由2.83%提升至3.83%。本工作为发展蓝光PeLED提供了一种可行的研究思路。

Abstract: Metal halide perovskite light-emitting diodes (PeLEDs) have attracted extensive attention due to their excellent optoelectronic properties. However, the performance of blue PeLEDs still lags behind that of their red and green counterparts, which limits their application in full-color displays. In this work, we investigated the influence of two different chlorine sources on the performance of blue quasi‑2D PeLEDs and further combined additive engineering to achieve efficient device fabrication. First, using inorganic PbCl₂ as the chlorine source, we adjusted the PbBr₂/PbCl₂ molar ratio, which shifted the electroluminescence (EL) peak from 512 nm to 496 nm. Although a higher PbCl₂ proportion could further blue‑shift the emission, the device performance deteriorated severely, preventing reliable characterization. Because PbCl₂ has poor solubility in DMSO, the film nucleation process became uncontrolled, leading to serious non‑radiative recombination. As a result, the external quantum efficiency (EQE) dropped sharply from 2.06% to 0.93%. In contrast, we replaced inorganic PbCl₂ with o‑fluorophenethylammonium chloride (o‑F‑PEACl), an organic spacer ligand that exhibits much better solubility. Using o‑F‑PEACl as the chlorine source, the EL peak shifted from 512 nm to 492 nm, and the maximum EQE increased from 2.06% to 2.83%. This comparison demonstrates that the organic chlorine source avoids the nucleation issues caused by the poor solubility of PbCl₂, thereby achieving a spectral blue shift and simultaneously improving device efficiency. Based on this, we further introduced methoxymethyl(diphenyl)phosphine oxide (MMPO) as an additive. The P=O group in MMPO can coordinate with halogen vacancies, passivating defects and suppressing non‑radiative recombination. Consequently, the maximum EQE was further enhanced from 2.83% to 3.83%. This work provides a feasible strategy for the development of blue PeLEDs.