Low‐Pressure Sensitive Piezochromic Fluorescence Switching of Tetraphenylethylene‐Anthraquinone

Abstract

AbstractSensing of low‐pressure signals is of great importance for cutting‐edge technologies. Organic piezochromic molecules offer a promising library of pressure sensitive materials which can be tailor‐designed toward specific requirements. However, very few examples of low‐pressure sensitive piezochromic fluorescent molecules have been obtained till date, and the underlying mechanisms are still in its infancy. Herein, we report highly sensitive piezochromic fluorescent switching under low‐pressure regimes (∼60 kPa) of tetraphenylethylene‐anthraquinone (TPE‐AQ) based on the controlled molecular design and polymorphic phase strategy. The influence of both intramolecular conformation effect and variations of intermolecular stacking modes on the piezochromic property of TPE‐AQ is investigated. The underlying mechanism of the low‐pressure sensitive piezochromic fluorescence switching is demonstrated to be closely related to the loosely packed molecular orientation, as confirmed by X‐ray diffraction measurements combined with simulations. This work provides a way to design highly efficient pressure sensors based on organic molecular systems.