High-Performance Nondoped Blue Delayed Fluorescence Organic Light-Emitting Diodes Featuring Low Driving Voltage and High Brightness

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

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Author(s)

  • Shi-Jie Zou
  • Feng-Ming Xie
  • Miao Xie
  • Yan-Qing Li
  • Tao Cheng
  • Xiao-Hong Zhang
  • Jian-Xin Tang

Detail(s)

Original languageEnglish
Article number1902508
Journal / PublicationAdvanced Science
Publication statusOnline published - 27 Nov 2019

Abstract

Thermally activated delayed fluorescence (TADF) provides great potential for the realization of efficient and stable organic light-emitting diodes (OLEDs). However, it is still challenging for blue TADF emitters to simultaneously achieve high efficiency, high brightness, and low Commission Internationale de l'Eclairage (CIE) y coordinate (CIEy) value. Here, the design and synthesis of two new benzonitrile-based TADF emitters (namely 2,6-di(9H-carbazol-9-yl)-3,5-bis(3,6-diphenyl-9H-carbazol-9-yl)benzonitrile (2PhCz2CzBn) and 2,6-di(9H-carbazol-9-yl)-3,5-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)benzonitrile (2tCz2CzBn)) with a symmetrical and rigid heterodonor configuration are reported. The TADF OLEDs doped with both the emitters can achieve a high external quantum efficiency (EQE) over 20% and narrowband blue emission of 464 nm with a CIEy < 0.2. Moreover, the incorporation of a terminal tert-butyl group can weaken the intermolecular ππ stacking in the nondoped TADF emitter, and thus significantly suppress self-aggregation-caused emission quenching for enhanced delayed fluorescence. A peak EQE of 21.6% is realized in the 2tCz2CzBn-based nondoped device with an extremely low turn-on voltage of 2.7 V, high color stability, a high brightness over 20 000 cd m−2, a narrow full-width at half-maximum of 70 nm, and CIE color coordinates of (0.167, 0.248).

Research Area(s)

  • blue emission, nondoped TADF emitters, organic light-emitting diodes, thermally activated delayed fluorescence, EXTERNAL QUANTUM EFFICIENCY, ROLL-OFF, EMITTERS, SINGLET

Citation Format(s)

High-Performance Nondoped Blue Delayed Fluorescence Organic Light-Emitting Diodes Featuring Low Driving Voltage and High Brightness. / Zou, Shi-Jie; Xie, Feng-Ming; Xie, Miao; Li, Yan-Qing; Cheng, Tao; Zhang, Xiao-Hong; Lee, Chun-Sing; Tang, Jian-Xin.

In: Advanced Science, 27.11.2019.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review