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Exploring Potential Energy Surfaces for Aggregation‐Induced Emission—From Solution to Crystal
Author(s) -
CrespoOtero Rachel,
Li Quansong,
Blancafort Lluís
Publication year - 2019
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201801649
Subject(s) - conical intersection , luminescence , chemical physics , excited state , intramolecular force , quantum yield , radiative transfer , intermolecular force , fluorescence , aggregation induced emission , potential energy , chemistry , ground state , aggregate (composite) , quantum , photochemistry , physics , nanotechnology , materials science , atomic physics , quantum mechanics , molecule , optics
Aggregation‐induced emission (AIE) is a phenomenon where non‐luminescent compounds in solution become strongly luminescent in aggregate and solid phase. It provides a fertile ground for luminescent applications that has rapidly developed in the last 15 years. In this review, we focus on the contributions of theory and computations to understanding the molecular mechanism behind it. Starting from initial models, such as restriction of intramolecular rotations (RIR), and the calculation of non‐radiative rates with Fermi's golden rule (FGR), we center on studies of the global excited‐state potential energy surfaces that have provided the basis for the restricted access to a conical intersection (RACI) model. In this model, which has been shown to apply for a diverse group of AIEgens, the lack of fluorescence in solution comes from radiationless decay at a CI in solution that is hindered in the aggregate state. We also highlight how intermolecular interactions modulate the photophysics in the aggregate phase, in terms of fluorescence quantum yield and emission color.