Efficient electron injection layer for thermal stability of top emission phosphorescent organic light emitting diodes

IF 2.7 4区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Organic Electronics Pub Date : 2024-05-17 DOI:10.1016/j.orgel.2024.107061

Thi Na Le , Ramachandran Elumalai , Seung Ju Ok , Yeonhwa Lee , Seung Yong Song , Min Chul Suh

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引用次数: 0

Abstract

Thermal stability holds significant importance in both high-resolution and large-area organic light-emitting diodes (OLEDs) due to its potential impacts on pixel shrinkage, thereby adversely affecting visual quality and long-term device functionality. The thermal instability could be from the thermal diffusion of metal ions or small molecules occurring at the interface between the electron injection layer (EIL) and the cathode material, influenced by differing surface properties and binding strength. In this study, we meticulously engineered magnesium fluoride (MgF₂) as EIL to mitigate the aforementioned challenges. Important physical properties associated with the EIL/cathode interaction were systematically analyzed. Employing Ag:Yb (2.5:1) as the cathode, we achieved notable enhancements in current efficiency and a reduced turn-on voltage for a green device operating under optical microcavity conditions. Thermal degradation test conducted over 240 h on fabricated devices revealed that employing MgF₂ as the EIL markedly enhanced thermal stability compared to devices utilizing Yb as the EIL reference. The robust EIL/cathode system observed herein is attributed to the high binding energy between the EIL and cathode materials utilized in this study.

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高效电子注入层提高顶部发射型磷光有机发光二极管的热稳定性

热稳定性对高分辨率和大面积有机发光二极管（OLED）具有重要意义，因为它可能会影响像素收缩，从而对视觉质量和设备的长期功能产生不利影响。热不稳定性可能是由于金属离子或小分子在电子注入层（EIL）和阴极材料之间的界面上发生热扩散，并受到不同表面特性和结合强度的影响。在本研究中，我们精心设计了氟化镁（MgF2）作为电子注入层，以减轻上述挑战。我们对与 EIL/阴极相互作用相关的重要物理特性进行了系统分析。采用银：镱（2.5:1）作为阴极，我们显著提高了电流效率，并降低了在光学微腔条件下运行的绿色器件的开启电压。对制造的器件进行的 240 小时热降解测试表明，与使用镱作为 EIL 参考的器件相比，使用 MgF2 作为 EIL 明显提高了热稳定性。本研究中观察到的 EIL/阴极系统的稳健性归功于 EIL 与阴极材料之间的高结合能。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Organic Electronics 工程技术-材料科学：综合

CiteScore

6.60

自引率

6.20%

发文量

238

审稿时长

44 days

期刊介绍： Organic Electronics is a journal whose primary interdisciplinary focus is on materials and phenomena related to organic devices such as light emitting diodes, thin film transistors, photovoltaic cells, sensors, memories, etc. Papers suitable for publication in this journal cover such topics as photoconductive and electronic properties of organic materials, thin film structures and characterization in the context of organic devices, charge and exciton transport, organic electronic and optoelectronic devices.