Non-doped blue and red phosphorescent OLEDs based on benzothiazole as bipolar host materials

IF 4.2 3区工程技术 Q2 CHEMISTRY, APPLIED

Dyes and Pigments Pub Date : 2025-06-18 DOI:10.1016/j.dyepig.2025.112977

Yongjie Hou , Siying Ye , Daqing Zhang , Yi Xu , Wei Shi , Haitao Zhou , Jinhai Huang , Bin Wei , Zhiyun Zhang

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引用次数: 0

Abstract

In this work, two novel bipolar host materials consisting of electron-rich carbazole and triphenylamine units and electron-deficient benzothiazole units, namely 4-(7-(4-(benzo[d]thiazol-2-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-yl)-N,N-diphenylaniline (TPA-BTZ) and 2-(4-(7-(4-(9H-carbazol-9-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-yl)phenyl)benzo-[d]thiazole (Cz-BTZ), were first designed and synthesized. By incorporating 9,9-dimethylfluorene π-bridge to increase the molecular rigidity and improve the photo-thermal stability and photo-luminescent quantum yields, all the materials exhibited excellent thermal stability with thermal decomposition temperature (5 % weight-loss temperature) of exceeding 380 °C. Red phosphorescent organic light-emitting diodes (PhOLEDs) based on these two materials were fabricated, which showed excellent performance with a very low turn-on voltage of 2.6 V. Remarkably, the device hosted by Cz-BTZ exhibited a maximal external quantum efficiencies (EQE_max) of 27.82 % and a maximal power efficiency of 36.21 lm/W. The device hosted by TPA-BTZ exhibited an EQE_max of 27.72 % and a maximum luminance of 21116 cd/m². Moreover, the Cz-BTZ-based OLED had a minor efficiency roll-off with the EQE remaining at 26.76 % when the luminance reached 1000 cd/m². In addition, the non-doped blue OLED based on Cz-BTZ achieved an EQE_max of 4.85 %. Designing bipolar phosphorescent host materials based on benzothiazole is a feasible approach for achieving highly efficient and thermally stable PhOLEDs.

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以苯并噻唑为双极性主体材料的非掺杂蓝色和红色磷光oled

本文首次设计并合成了由富电子咔唑和三苯胺单元和缺电子苯并噻唑单元组成的新型双极性主体材料，即4-（7-（4-（苯并[d]噻唑-2-基）苯基）-9,9-二甲基- 9h -芴-2-基）- n， n-二苯基苯胺（TPA-BTZ）和2-（4-（7-（4-（9h -咔唑-9-基）苯基）-9,9-二甲基- 9h -芴-2-基）苯基）苯并[d]噻唑（Cz-BTZ）。通过掺入9,9-二甲基芴π桥增加分子刚度，提高光热稳定性和光致发光量子产率，材料均表现出优异的热稳定性，热分解温度（5%失重温度）均超过380℃。在这两种材料的基础上制备了具有优异性能的红色磷光有机发光二极管（PhOLEDs），其导通电压极低，为2.6 V。值得注意的是，Cz-BTZ承载器件的最大外量子效率（EQEmax）为27.82%，最大功率效率为36.21 lm/W。TPA-BTZ承载的器件EQEmax为27.72%，最大亮度为21116 cd/m2。此外，基于cz - btz的OLED具有较小的效率滚降，当亮度达到1000 cd/m2时，EQE保持在26.76%。此外，基于Cz-BTZ的无掺杂蓝色OLED实现了4.85%的EQEmax。设计基于苯并噻唑的双极磷光主体材料是实现高效、热稳定的发光二极管的可行途径。

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

Dyes and Pigments 工程技术-材料科学：纺织

CiteScore

8.20

自引率

13.30%

发文量

933

审稿时长

33 days

期刊介绍： Dyes and Pigments covers the scientific and technical aspects of the chemistry and physics of dyes, pigments and their intermediates. Emphasis is placed on the properties of the colouring matters themselves rather than on their applications or the system in which they may be applied. Thus the journal accepts research and review papers on the synthesis of dyes, pigments and intermediates, their physical or chemical properties, e.g. spectroscopic, surface, solution or solid state characteristics, the physical aspects of their preparation, e.g. precipitation, nucleation and growth, crystal formation, liquid crystalline characteristics, their photochemical, ecological or biological properties and the relationship between colour and chemical constitution. However, papers are considered which deal with the more fundamental aspects of colourant application and of the interactions of colourants with substrates or media. The journal will interest a wide variety of workers in a range of disciplines whose work involves dyes, pigments and their intermediates, and provides a platform for investigators with common interests but diverse fields of activity such as cosmetics, reprographics, dye and pigment synthesis, medical research, polymers, etc.