Manipulating crystals through photoexcitation-induced molecular realignment

Abstract

Numerous efforts have been invested in improving the uniform rearrangement in photoinduced crystal engineering due to the fact that molecular ordering is hardly addressed via a traditional photochemical process as a whole. Herein, we present a nonequilibrium strategy, photoexcitation-induced molecular realignment, to manipulate crystal growth and transformation. This strategy allows a dynamic change of molecular conformation upon continuous photoirradiation, wherein the molecular structure remains intact. Consequently, crystal photomanipulation from solution growth to single crystals, polycrystals, and finally to doped films is achieved, accompanied by the phototuning of a series of crystal optical behaviors (e.g. absorption, refraction, fluorescence, and room-temperature phosphorescence). The developed materials are stable because of the molecular conformation kinetically trapped within the minimum energy on the basis of a steady-state design conception. This strategy, relying on the materialization of photoexcitation, provides a paradigm for controlling molecular ordering by light.