Blue organic light-emitting diodes realizing external quantum efficiency over 25% using thermally activated delayed fluorescence emitters

Takuya Miwa, Shosei Kubo, Katsuyuki Shizu, Takeshi Komino, Chihaya Adachi, Hironori Kaji

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Improving the performance of blue organic light-emitting diodes (OLEDs) is needed for full-colour flat-panel displays and solid-state lighting sources. The use of thermally activated delayed fluorescence (TADF) is a promising approach to efficient blue electroluminescence. However, the difficulty of developing efficient blue TADF emitters lies in finding a molecular structure that simultaneously incorporates (i) a small energy difference between the lowest excited singlet state (S1) and the lowest triplet state (T1), ΔE ST, (ii) a large oscillator strength, f, between S1 and the ground state (S0), and (iii) S1 energy sufficiently high for blue emission. In this study, we develop TADF emitters named CCX-I and CCX-II satisfying the above requirements. They show blue photoluminescence and high triplet-to-singlet up-conversion yield. In addition, their transition dipole moments are horizontally oriented, resulting in further increase of their electroluminescence efficiency. Using CCX-II as an emitting dopant, we achieve a blue OLED showing a high external quantum efficiency of 25.9%, which is one of the highest EQEs in blue OLEDs reported previously.

Original languageEnglish
Pages (from-to)284
JournalScientific Reports
Volume7
Issue number1
DOIs
Publication statusPublished - Mar 21 2017

Fingerprint

Fluorescence
Light
Molecular Structure
Lighting
Color

Cite this

Blue organic light-emitting diodes realizing external quantum efficiency over 25% using thermally activated delayed fluorescence emitters. / Miwa, Takuya; Kubo, Shosei; Shizu, Katsuyuki; Komino, Takeshi; Adachi, Chihaya; Kaji, Hironori.

In: Scientific Reports, Vol. 7, No. 1, 21.03.2017, p. 284.

Research output: Contribution to journalArticle

Miwa, Takuya ; Kubo, Shosei ; Shizu, Katsuyuki ; Komino, Takeshi ; Adachi, Chihaya ; Kaji, Hironori. / Blue organic light-emitting diodes realizing external quantum efficiency over 25% using thermally activated delayed fluorescence emitters. In: Scientific Reports. 2017 ; Vol. 7, No. 1. pp. 284.
@article{d5038ddf6bfb4c5c930c7bc22d935a12,
title = "Blue organic light-emitting diodes realizing external quantum efficiency over 25{\%} using thermally activated delayed fluorescence emitters",
abstract = "Improving the performance of blue organic light-emitting diodes (OLEDs) is needed for full-colour flat-panel displays and solid-state lighting sources. The use of thermally activated delayed fluorescence (TADF) is a promising approach to efficient blue electroluminescence. However, the difficulty of developing efficient blue TADF emitters lies in finding a molecular structure that simultaneously incorporates (i) a small energy difference between the lowest excited singlet state (S1) and the lowest triplet state (T1), ΔE ST, (ii) a large oscillator strength, f, between S1 and the ground state (S0), and (iii) S1 energy sufficiently high for blue emission. In this study, we develop TADF emitters named CCX-I and CCX-II satisfying the above requirements. They show blue photoluminescence and high triplet-to-singlet up-conversion yield. In addition, their transition dipole moments are horizontally oriented, resulting in further increase of their electroluminescence efficiency. Using CCX-II as an emitting dopant, we achieve a blue OLED showing a high external quantum efficiency of 25.9{\%}, which is one of the highest EQEs in blue OLEDs reported previously.",
author = "Takuya Miwa and Shosei Kubo and Katsuyuki Shizu and Takeshi Komino and Chihaya Adachi and Hironori Kaji",
year = "2017",
month = "3",
day = "21",
doi = "10.1038/s41598-017-00368-5",
language = "English",
volume = "7",
pages = "284",
journal = "Scientific Reports",
issn = "2045-2322",
publisher = "Nature Publishing Group",
number = "1",

}

TY - JOUR

T1 - Blue organic light-emitting diodes realizing external quantum efficiency over 25% using thermally activated delayed fluorescence emitters

AU - Miwa, Takuya

AU - Kubo, Shosei

AU - Shizu, Katsuyuki

AU - Komino, Takeshi

AU - Adachi, Chihaya

AU - Kaji, Hironori

PY - 2017/3/21

Y1 - 2017/3/21

N2 - Improving the performance of blue organic light-emitting diodes (OLEDs) is needed for full-colour flat-panel displays and solid-state lighting sources. The use of thermally activated delayed fluorescence (TADF) is a promising approach to efficient blue electroluminescence. However, the difficulty of developing efficient blue TADF emitters lies in finding a molecular structure that simultaneously incorporates (i) a small energy difference between the lowest excited singlet state (S1) and the lowest triplet state (T1), ΔE ST, (ii) a large oscillator strength, f, between S1 and the ground state (S0), and (iii) S1 energy sufficiently high for blue emission. In this study, we develop TADF emitters named CCX-I and CCX-II satisfying the above requirements. They show blue photoluminescence and high triplet-to-singlet up-conversion yield. In addition, their transition dipole moments are horizontally oriented, resulting in further increase of their electroluminescence efficiency. Using CCX-II as an emitting dopant, we achieve a blue OLED showing a high external quantum efficiency of 25.9%, which is one of the highest EQEs in blue OLEDs reported previously.

AB - Improving the performance of blue organic light-emitting diodes (OLEDs) is needed for full-colour flat-panel displays and solid-state lighting sources. The use of thermally activated delayed fluorescence (TADF) is a promising approach to efficient blue electroluminescence. However, the difficulty of developing efficient blue TADF emitters lies in finding a molecular structure that simultaneously incorporates (i) a small energy difference between the lowest excited singlet state (S1) and the lowest triplet state (T1), ΔE ST, (ii) a large oscillator strength, f, between S1 and the ground state (S0), and (iii) S1 energy sufficiently high for blue emission. In this study, we develop TADF emitters named CCX-I and CCX-II satisfying the above requirements. They show blue photoluminescence and high triplet-to-singlet up-conversion yield. In addition, their transition dipole moments are horizontally oriented, resulting in further increase of their electroluminescence efficiency. Using CCX-II as an emitting dopant, we achieve a blue OLED showing a high external quantum efficiency of 25.9%, which is one of the highest EQEs in blue OLEDs reported previously.

U2 - 10.1038/s41598-017-00368-5

DO - 10.1038/s41598-017-00368-5

M3 - Article

C2 - 28325941

VL - 7

SP - 284

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

IS - 1

ER -