Recent Advances in Mechano-responsive Fluorescent Organic and Organometallic Compounds: Structural Diversity, Phase Transformation and Applications

Abstract

Developing smart luminescent materials, especially stimulus-responsive fluorescent materials, is a goal of great importance, as well as a challenge. Mechano-responsive fluorescence is a property whereby the fluorescence characteristics (i.e., emission color, quantum yield, or lifetime) of a species change as a result of mechanical stimulation. In general, the said mechanical stimulation causes a phase transition in the material, and it simultaneously induces a fresh interaction of the luminous, resulting in a change in the color of the photoluminescence emission. Therefore, the transition of a material from crystalline-to-amorphous, from amorphous-to-crystalline, or from a crystalline to another, as well as the phase transformation of liquid crystals, can contribute to changes in fluorescence emission triggered by a mechanic stimulus. This article briefly reviews the development of such mechano-responsive fluorescent compounds, which consist of organic or organometallic molecules, and the emerging trends in this research field.