Managing Excitons and Charges for High-Performance Fluorescent White Organic Light-Emitting Diodes

Zhongbin Wu; Qi Wang; Ling Yu; Jiangshan Chen; Xianfeng Qiao; Tansir Ahamad; Saad M Alshehri; Chuluo Yang; Dongge Ma

doi:10.1021/acsami.6b10087

Managing Excitons and Charges for High-Performance Fluorescent White Organic Light-Emitting Diodes

ACS Appl Mater Interfaces. 2016 Oct 26;8(42):28780-28788. doi: 10.1021/acsami.6b10087. Epub 2016 Oct 12.

Authors

Zhongbin Wu¹, Qi Wang², Ling Yu³, Jiangshan Chen⁴, Xianfeng Qiao⁴, Tansir Ahamad⁵, Saad M Alshehri^{5

6}, Chuluo Yang³, Dongge Ma^{1

4

5}

Affiliations

¹ State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, P. R. China.
² Department of Electrical Engineering and Computer Science, University of Michigan , Ann Arbor, Michigan 48109, United States.
³ Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University , Wuhan 430072, P. R. China.
⁴ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology , Guangzhou 510640, P. R. China.
⁵ Department of Chemistry, King Saud University , Riyadh 11451, Kingdom of Saudi Arabia.
⁶ Department of Chemistry, College of Science & General Studies, Alfaisal University , Riyadh 11451, Kingdom of Saudi Arabia.

PMID: 27706937
DOI: 10.1021/acsami.6b10087

Abstract

The simultaneous realization of high efficiency, stable spectra, high color rendering index (CRI), and low-efficiency roll-off in a fluorescent white organic light-emitting diode (WOLED) still remains a big challenge. Here, we demonstrate high-performance conventional fluorescent-dopant-based WOLEDs by strategic management of singlet and triplet excitons within an efficient emissive zone. This design consists of two separated red/green sub-EMLs with ultralow doping concentration and a sandwiched sub-EML doped with red and green fluorescent dyes at a relatively high concentration, which can harness all electrogenerated excitons and reduce the energy loss to the utmost extent. Accordingly, the resulting WOLED realizes an external quantum efficiency (EQE) of 18.2% with a maximum power efficiency of 44.6 lm W^-1. At the practical luminance of 1000 cd m^-2 for the lighting source, the EQE still remains as high as 16.2% with a CRI of 82 and stable color spectra. A comprehensive understanding of the device working mechanism is performed to guide design of efficient and stable fluorescent WOLEDs.

Keywords: conventional fluorescent dopant; exciton management; fluorescent white organic light-emitting diodes; high performance; host−guest synergistic effect.