RESUMO
Invited for the cover of this issue are Prof. Wenjing Tian and co-workers at Jilin University. The image depicts the highly sensitive piezochromic fluorescence switching of tetraphenylethylene-anthraquinone under low-pressure regimes (â¼60â kPa). Read the full text of the article at 10.1002/chem.202301070.
RESUMO
Sensing 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 (â¼60â 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.