Photoluminescence in a Thermally Activated Delayed Fluorescence Emitter for Organic Light-emitting Diodes

Akitsugu NIWA; Kensho TAKAKI; Takashi KOBAYASHI; Takashi NAGASE; Kenichi GOUSHI; Chihaya ADACHI; Hiroyoshi NAITO

doi:10.11370/isj.55.143

Regular Paper

Photoluminescence in a Thermally Activated Delayed Fluorescence Emitter for Organic Light-emitting Diodes

Akitsugu NIWA, Kensho TAKAKI, Takashi KOBAYASHI, Takashi NAGASE, Kenichi GOUSHI, Chihaya ADACHI, Hiroyoshi NAITO

Author information

Akitsugu NIWA
Department of Physics and Electronics, Osaka Prefecture University
Kensho TAKAKI
Department of Physics and Electronics, Osaka Prefecture University
Takashi KOBAYASHI
Department of Physics and Electronics, Osaka Prefecture University
The Research Institute for Molecular Electronic Devices (RIMED)
Takashi NAGASE
Department of Physics and Electronics, Osaka Prefecture University
The Research Institute for Molecular Electronic Devices (RIMED)
Kenichi GOUSHI
Center for Organic Photonics and Electronics Research (OPERA), Kyushu University
JST, ERATO, Adachi Molecular Exciton Engineering Project
International Institute for Carbon Neutral Energy Research (WPI-I² CNER), Kyushu University
Chihaya ADACHI
Center for Organic Photonics and Electronics Research (OPERA), Kyushu University
JST, ERATO, Adachi Molecular Exciton Engineering Project
International Institute for Carbon Neutral Energy Research (WPI-I² CNER), Kyushu University
Hiroyoshi NAITO
Department of Physics and Electronics, Osaka Prefecture University
The Research Institute for Molecular Electronic Devices (RIMED)

Keywords: Organic light-emitting diodes, Thermally activated delayed fluorescence (TADF), Rate equations, Decay rates, Thermal quenching

JOURNAL FREE ACCESS

2016 Volume 55 Issue 2 Pages 143-148

DOI https://doi.org/10.11370/isj.55.143

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Abstract

Thermally activated delayed fluorescence (TADF) has attracted much attention for realization of highly-efficient and low-cost organic light emitting diodes (OLEDs). OLEDs based on 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), which is one of highly-efficient TADF emitters, have been demonstrated to exhibit external quantum efficiency more than 19%. To study the decay rates from excited states of 4CzIPN, the temperature dependence of photoluminescence quantum efficiency (PLQE) has been measured in the weak photoexcitation limit in 4CzIPN-doped 1,3-bis(9-carbazolyl)benzene thin films. Characteristic features of the temperature dependence of PLQE in the weak photoexcitation limit are found, and examined by using rate equations of singlet and triplet densities.

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