Phenothiazine-Based Organic Single Crystal with Flexibility, Piezochromism, and Fluorescent Waveguide Properties

The development of organic single crystals with combined properties, including flexibility, piezochromism, and optical waveguiding, holds paramount importance for advancing new optoelectronic devices. Herein, a long, needle-shaped organic plastic crystal based on phenothiazine was fabricated, and it emits bright yellow-green fluorescence under ultraviolet light excitation. Investigations into its piezochromism property via a diamond anvil cell revealed that this phenothiazine-based material performed a pressure-induced emission enhancement effect under relatively low pressures (0–0.6 GPa). Furthermore, optical waveguide tests were conducted on the crystal in both linear and plastic deformation states, and the results revealed no significant attenuation of its light transmission properties. This phenothiazine-based crystal exhibits flexibility, piezochromism, and optical waveguiding properties, which will be valuable as a sensing material for developing integrated pressure sensors.