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Crystallization‐Induced Emission Enhancement and Amplified Spontaneous Emission from a CF 3 ‐Containing Excited‐State Intramolecular‐Proton‐Transfer Molecule
Author(s) -
Park Sanghyuk,
Kwon Ji Eon,
Park SunYoung,
Kwon OhHoon,
Kim Joon Ki,
Yoon SeongJun,
Chung Jong Won,
Whang Dong Ryeol,
Park Sang Kyu,
Lee Dong Ki,
Jang DuJeon,
Gierschner Johannes,
Park Soo Young
Publication year - 2017
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201700353
Subject(s) - intramolecular force , materials science , intermolecular force , excited state , photochemistry , molecule , stacking , hydrogen bond , amplified spontaneous emission , fluorescence , stimulated emission , crystal (programming language) , crystallography , laser , chemistry , stereochemistry , atomic physics , optics , organic chemistry , physics , computer science , programming language
In this work, a simple but effective molecular design strategy is developed for the generation of intense blue emission in the solid state including single crystals through the multiple secondary intermolecular interactions such as CF…HC hydrogen bonding. The synthesized novel imidazole‐based excited‐state intramolecular proton transfer (ESIPT) molecule, 2‐(1‐(3,5‐bis(trifluoromethyl)phenyl)‐4,5‐diphenyl‐1H‐imidazol‐2‐yl)phenol (HPI‐CF 3 ), shows significantly enhanced blue fluorescence in single crystal (Φ F = 0.67) compared to faint emission in solution (Φ F < 0.05). It is considered that tight but slipped stacking structure of HPI‐CF 3 molecules in the single crystal not only effectively suppresses the nonradiative decay pathways such as twist intramolecular charge transfer but also induces highly allowed transition character. Taking advantage of the crystallization‐induced emission enhancement characteristics and four‐level ESIPT photocycle process of HPI‐CF 3 , an efficient amplified spontaneous emission at 475 nm with a threshold of 13.1 mJ cm −2 is observed from the single crystal by picosecond laser optical pumping.