Premium
Aggregation‐Induced Photon Upconversion through Control of the Triplet Energy Landscapes of the Solution and Solid States
Author(s) -
Duan Pengfei,
Yanai Nobuhiro,
Kurashige Yuki,
Kimizuka Nobuo
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201501449
Subject(s) - photon upconversion , excited state , annihilation , photoisomerization , photochemistry , chemistry , triplet state , chemical physics , isomerization , photon , atomic physics , physics , optics , quantum mechanics , organic chemistry , ion , catalysis
Aggregation‐induced photon upconversion (iPUC) based on control of the triplet energy landscape is demonstrated for the first time. When a triplet state of a cyano‐substituted 1,4‐distyrylbenzene derivative is sensitized in solution, no upconverted emission based on triplet–triplet annihilation (TTA) was observed. In stark contrast, crystalline solids obtained by drying the solution revealed clear upconverted emission. Theoretical studies unveiled an underlying switching mechanism: the excited triplets in solution immediately decay back to the ground state through conformational twisting around a CC bond and photoisomerization, whereas this deactivation path is effectively inhibited in the solid state. The finding of iPUC phenomena highlights the importance of controlling excited energy landscapes in condensed molecular systems.