Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect

Dongdong Zhang; Lian Duan; Yunge Zhang; Minghan Cai; Deqiang Zhang; Yong Qiu

doi:10.1038/lsa.2015.5

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Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect

Original Articles

- Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect
- Light: Science & Applications Vol. 4, Issue 1, (2015)
- Affiliations：
  
  Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
- Author bio：
  
  L Duan, Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China E-mail: duanl@mail.tsinghua.edu.cn
- Funds：
- DOI：10.1038/lsa.2015.5
  CLC：
- Published：2015-03，
  
  Published Online：14 November 2014，
  
  Received：01 August 2014，
  
  Revised：30 October 2014，
  
  Accepted：04 November 2014
- Accepted：
Scan QR Code
Zhang, D. D. et al. Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect. Light: Science & Applications, 4, e232 (2015).
DOI：

Zhang, D. D. et al. Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect. Light: Science & Applications, 4, e232 (2015). DOI： 10.1038/lsa.2015.5.

摘要

Abstract

To attain high efficiencies in hybrid white organic light-emitting diodes (WOLEDs)

mutual quenching of the fluorophors and phosphors should be minimized. Efforts have been devoted to reducing the triplet quenching of phosphors; however

the quenching of fluorophors by the external heavy-atom effect (EHA) introduced by the phosphors is often ignored. Here

we observed that conventional fluorophors and fluorophors with thermally activated delayed fluorescence (TADF) behave differently in the presence of EHA perturbers. The efficiencies of the conventional fluorophors suffer greatly from the EHA

whereas the TADF fluorophors exhibit negligible changes

which makes TADF materials ideal fluorophors for hybrid devices. WOLEDs using a blue TADF fluorophor and an orange phosphor achieve a maximum forward viewing external quantum efficiency of 19.6% and a maximum forward viewing power efficiency of 50.2 lm W

−1

among the best values for hybrid WOLEDs. This report is the first time that the EHA effect has been considered in hybrid WOLEDs and that a general strategy toward highly efficient hybrid WOLEDs with simple structures is proposed.

关键词

Keywords

external heavy-atom effecthybrid white OLEDsthermally activated delayed fluorescence

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