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Title: High performance blue-emitting organic light-emitting diodes from thermally activated delayed fluorescence: A guest/host ratio study

Abstract

Emitters displaying thermally activated delayed fluorescence (TADF) can drive highly efficient organic light-emitting diodes (OLEDs). Such emitters are usually incorporated into the emissive layer (EML) at a relatively low concentration (<20 wt. %) with respect to a host material, a guest-host method inherited from conventional fluorescent or phosphorescent OLEDs. In this work, detailed studies on OLEDs, in which the concentration of oBFCzTrz (a blue-emitter displaying TADF) in a DPEPO host was varied from 8 to 100 wt. %, reveals that oBFCzTrz displays ambipolar transport and limited fluorescence-quenching due to aggregation. For instance, a neat film of oBFCzTrz maintains a photoluminescence quantum yield of 82%. We determine that OLEDs with an EML having an oBFCzTrz concentration of 50 wt. % in DPEPO yield a maximum external quantum efficiency (EQE) of 25.5% with an EQE roll-off of 10% in the range from 10 to 1000 cd/m 2 and Commission Internationale de l'Eclairage color coordinates of (0.20, 0.44). OLEDs with smaller or larger oBFCzTrz concentrations display smaller maximum EQE values. OLEDs with a neat oBFCzTrz EML display a maximum EQE of 14.0%. Time-resolved electroluminescent decay studies, and analysis using a simple model, reveal significant differences in transport, trapping, and recombination in these devices.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [1]
  1. Georgia Inst. of Technology, Atlanta, GA (United States)
Publication Date:
Research Org.:
Georgia Inst. of Technology, Atlanta, GA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1540237
Alternate Identifier(s):
OSTI ID: 1463225
Grant/Contract Number:  
EE0008205; De-EE0008205
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 124; Journal Issue: 5; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English

Citation Formats

Zhang, Xiaoqing, Fuentes-Hernandez, Canek, Zhang, Yadong, Cooper, Matthew W., Barlow, Stephen, Marder, Seth R., and Kippelen, Bernard. High performance blue-emitting organic light-emitting diodes from thermally activated delayed fluorescence: A guest/host ratio study. United States: N. p., 2018. Web. doi:10.1063/1.5041447.
Zhang, Xiaoqing, Fuentes-Hernandez, Canek, Zhang, Yadong, Cooper, Matthew W., Barlow, Stephen, Marder, Seth R., & Kippelen, Bernard. High performance blue-emitting organic light-emitting diodes from thermally activated delayed fluorescence: A guest/host ratio study. United States. doi:10.1063/1.5041447.
Zhang, Xiaoqing, Fuentes-Hernandez, Canek, Zhang, Yadong, Cooper, Matthew W., Barlow, Stephen, Marder, Seth R., and Kippelen, Bernard. Tue . "High performance blue-emitting organic light-emitting diodes from thermally activated delayed fluorescence: A guest/host ratio study". United States. doi:10.1063/1.5041447. https://www.osti.gov/servlets/purl/1540237.
@article{osti_1540237,
title = {High performance blue-emitting organic light-emitting diodes from thermally activated delayed fluorescence: A guest/host ratio study},
author = {Zhang, Xiaoqing and Fuentes-Hernandez, Canek and Zhang, Yadong and Cooper, Matthew W. and Barlow, Stephen and Marder, Seth R. and Kippelen, Bernard},
abstractNote = {Emitters displaying thermally activated delayed fluorescence (TADF) can drive highly efficient organic light-emitting diodes (OLEDs). Such emitters are usually incorporated into the emissive layer (EML) at a relatively low concentration (<20 wt. %) with respect to a host material, a guest-host method inherited from conventional fluorescent or phosphorescent OLEDs. In this work, detailed studies on OLEDs, in which the concentration of oBFCzTrz (a blue-emitter displaying TADF) in a DPEPO host was varied from 8 to 100 wt. %, reveals that oBFCzTrz displays ambipolar transport and limited fluorescence-quenching due to aggregation. For instance, a neat film of oBFCzTrz maintains a photoluminescence quantum yield of 82%. We determine that OLEDs with an EML having an oBFCzTrz concentration of 50 wt. % in DPEPO yield a maximum external quantum efficiency (EQE) of 25.5% with an EQE roll-off of 10% in the range from 10 to 1000 cd/m2 and Commission Internationale de l'Eclairage color coordinates of (0.20, 0.44). OLEDs with smaller or larger oBFCzTrz concentrations display smaller maximum EQE values. OLEDs with a neat oBFCzTrz EML display a maximum EQE of 14.0%. Time-resolved electroluminescent decay studies, and analysis using a simple model, reveal significant differences in transport, trapping, and recombination in these devices.},
doi = {10.1063/1.5041447},
journal = {Journal of Applied Physics},
number = 5,
volume = 124,
place = {United States},
year = {2018},
month = {8}
}

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Works referenced in this record:

Highly efficient phosphorescent emission from organic electroluminescent devices
journal, September 1998

  • Baldo, M. A.; O'Brien, D. F.; You, Y.
  • Nature, Vol. 395, Issue 6698, p. 151-154
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