Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Highly Efficient Deep‐Blue Organic Light‐Emitting Diodes Based on Rational Molecular Design and Device Engineering

Highly Efficient Deep‐Blue Organic Light‐Emitting Diodes Based on Rational Molecular Design and... There is increasing interest in thermally activated delayed fluorescence (TADF) in materials, and to understand its mechanism in the excited state dynamics. Recent challenges include color purity, efficient deep‐blue emission, fast exciton decay lifetimes, high reverse intersystem crossing rates (kRISC), low‐efficiency roll‐off in organic light‐emitting diodes (OLEDs), and long device lifetimes. Here, a series of compounds having benzonitrile and carbazole rings are examined, that provide a detailed understanding of the excited states, and a guideline for high‐performance TADF. A dense alignment of the excited states with several different characters within a small energy range results in high kRISC of >2 × 106 s−1, while maintaining radiative rate constants (kr) >107 s−1. OLEDs based on the optimum compound exhibit a low‐efficiency roll‐off and a CIEy (y color coordinate of Commission Internationale de l'Éclairage) <0.4. TADF‐assisted fluorescence (TAF) OLED exhibits a maximum external quantum efficiency of 22.4% with CIE coordinates (0.13,0.15). This work also provides insights for device engineering and molecular designs. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Advanced Functional Materials Wiley

Highly Efficient Deep‐Blue Organic Light‐Emitting Diodes Based on Rational Molecular Design and Device Engineering

Loading next page...
 
/lp/wiley/highly-efficient-deep-blue-organic-light-emitting-diodes-based-on-kibJ4T1Xd2

References (73)

Publisher
Wiley
Copyright
© 2022 Wiley‐VCH GmbH
ISSN
1616-301X
eISSN
1616-3028
DOI
10.1002/adfm.202204352
Publisher site
See Article on Publisher Site

Abstract

There is increasing interest in thermally activated delayed fluorescence (TADF) in materials, and to understand its mechanism in the excited state dynamics. Recent challenges include color purity, efficient deep‐blue emission, fast exciton decay lifetimes, high reverse intersystem crossing rates (kRISC), low‐efficiency roll‐off in organic light‐emitting diodes (OLEDs), and long device lifetimes. Here, a series of compounds having benzonitrile and carbazole rings are examined, that provide a detailed understanding of the excited states, and a guideline for high‐performance TADF. A dense alignment of the excited states with several different characters within a small energy range results in high kRISC of >2 × 106 s−1, while maintaining radiative rate constants (kr) >107 s−1. OLEDs based on the optimum compound exhibit a low‐efficiency roll‐off and a CIEy (y color coordinate of Commission Internationale de l'Éclairage) <0.4. TADF‐assisted fluorescence (TAF) OLED exhibits a maximum external quantum efficiency of 22.4% with CIE coordinates (0.13,0.15). This work also provides insights for device engineering and molecular designs.

Journal

Advanced Functional MaterialsWiley

Published: Aug 1, 2022

Keywords: DABNA; hyperfluorescence; organic light‐emitting diodes; reverse intersystem crossing; TADF

There are no references for this article.