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The Importance of Excited‐State Energy Alignment for Efficient Exciplex Systems Based on a Study of Phenylpyridinato Boron Derivatives
Author(s) -
Mamada Masashi,
Tian Guojian,
Nakanotani Hajime,
Su Jianhua,
Adachi Chihaya
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201804218
Subject(s) - excited state , excimer , acceptor , boron , photoluminescence , photochemistry , materials science , fluorescence , chemistry , chemical physics , optoelectronics , atomic physics , optics , physics , organic chemistry , condensed matter physics
Understanding excited‐state dynamics is critical for improving the photoluminescence (PL) efficiency of exciplexes. A series of exciplexes based on conventional hole‐transporting materials as donor and newly developed phenylpyridinato boron derivatives as acceptor were investigated. High PL efficiencies were achieved in only some combinations, and a large difference in performance among combinations provided insight into nonradiative processes in exciplex systems. Furthermore, the triplet local excited states ( 3 LE) of each donor and acceptor were found play an important role in triplet exciplex harvesting. Significant contributions from triplets were clearly observed when the charge‐transfer excited states ( 1 CT and 3 CT) and 3 LE were ideally aligned. We also demonstrated fine control of relative energy alignment via the concentration to improve the PL efficiency.