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Enhancing the Kinetic Stability and Lifetime of Organic Light‐Emitting Diodes based on Bipolar Hosts by using Spiroconjugation
Author(s) -
Son Wonjoon,
Kwak SeungYeon,
Koo Hyun,
Choi Byoungki,
Kim Sunghan,
Lee Hyo Sug,
Whangbo MyungHwan,
Choi Hyeonho
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201800025
Subject(s) - oled , kinetic energy , diode , optoelectronics , materials science , photochemistry , chemistry , nanotechnology , physics , quantum mechanics , layer (electronics)
We examined how to enhance the lifetime of organic light‐emitting diodes (OLEDs) based on bipolar host molecules ET‐HT, where ET and HT refer to electron‐ and hole‐transporting units, respectively, by analyzing their thermodynamic and kinetic stabilities. Our DFT calculations reveal that the thermodynamic stability of ET‐HT is determined by that of its anion, which is difficult to improve by chemical modifications of ET and HT. The kinetic stability of ET‐HT can be enhanced by the spiroconjugation between ET and HT, which occurs when their π‐frameworks are extended and have an orthogonal arrangement. Green OLED devices were fabricated by using ET‐HTs with and without spiroconjugation, to find that the device with spiroconjugation has a lifetime that is approximately 6 times longer than the one without spiroconjugation.