Reversible switching of solid-state luminescence by heat-induced interconversion of molecular packing

Abstract

Dynamic switching of solid-sate luminescence with high contrast and reproducibility is a challenging task but important for several optoelectronic applications. One promising approach towards this end is to control the mode of solid-state packing of luminescent organic chromophores with an external stimulus. Herein, we present the heat-induced interconversion of molecular packing in acceptor–donor–acceptor type divinylbenzene derivatives. This interconversion is associated with the switching of solid-state luminescence from red to greenish-yellow (Δλ = 95 nm). A detailed investigation of the photophysical properties provided molecular and supramolecular level comprehension of the factors guiding the luminescence switching. The transition between different packing modes is associated with differential excited state coupling and excitation energy migration efficiencies due to the variance in the chromophore organization. Viewed more broadly, our findings illustrate that subtle control over energy migration processes in molecular assemblies by heating may result in functional organic materials with switchable luminescence.