Structural Tuning and Piezoluminescence Phenomenon in Trithiocyanuric Acid

As an essential thermodynamic variable, pressure has a powerful ability to accurately control molecular structures and properties by modulating the noncovalent interactions therein. Based on this point, we utilized pressure to tune the structure and properties of trithiocyanuric acid (C3H3N3S3, TTCA), gaining deeper insight into its structural nature and structureproperty relationships. During compression, layered TTCA undergoes molecular distortion and relative slippage between interlayers, as well as anisotropic and stepwise shrinkage of intralayer six-molecule rings. Importantly, these structural variations have a great influence on the luminescence properties of TTCA. Piezoluminescence is observed above similar to 4 GPa, acompanied by the calculated shifting of valence-band top. In experiments, detailed stepwise compression of the intralayer structure was captured directly. The observations combine the microscopic structure and macroscopic properties together and are beneficial for the further design of luminescence materials, as well as pressure sensors and pressure switches.