Two different emission enhancement of trans-stilbene crystal under high pressure: Different evolution of structure

Mechanoresponsive luminescent (MRL) materials have drawn extensive concern due to their potential applications in mechanical sensors, memory chips, and security inks; especially these possessing high emission efficiency. In this work, we found trans-stilbene crystal exhibited two different pressure-induced emission enhancement (PIEE) behaviors at different pressure areas. The structural characterizations combined with density functional theory calculation indicate that the first emission enhancement was due to the decrease of nonradiation transition by the weaken of energy exchange process between atoms and lattice. And the second emission enhancement was attributed to the strengthen of C-H...C interactions from the non-planarization comformation. The results regarding the mechanoresponsive behavior of trans-stilbene offered a deep insight into PIEE from the structural point of view, which will facilitate the design of and search for high-performance MRL materials.