Amorphization-Enhanced Emission (AEE) of Tetraphenylethylene

Abstract

The molecular stacking mode of organic luminescent materials directly affects the mechanoresponsive luminescence (MRL) properties. Although crystallization-enhanced emission applies to most organic luminescent materials, the emission of the amorphous phase in MRL materials with two-state switching is generally redder and weaker. Herein, the amorphization-enhanced emission (AEE) phenomenon from tetraphenylethylene (TPE) was observed by the rapid compression of its melt caused by the transformation of the TPE from a liquid to an amorphous solid. The fluorescence emission of amorphous TPE was significantly stronger than that of crystalline TPE throughout the depressurization process. As pure hydrocarbons, intermolecular interactions rely more on C−H•••π, and amorphous aggregates attributed to enhance this interaction, leading to increased efficiency. The experimental approach provided in this paper is universally applicable to organic luminescent materials that remain stable after melting, which perfectly inherits the liquid phase's properties and helps further investigate the luminescence mechanism of AEE materials.