Photochromism, Mechanochromism, and Acidochromism of Pyrene-4-(1,2,2-triphenylethenyl)pyridine Cocrystal for Anticounterfeiting and White-Light Emission

Multistimuli-responsive crystalline materials hold significant potential for optoelectronic devices, chemical sensing, and encryption. However, cocrystal systems exhibiting stimuli responsiveness with high quantum yield are still limited. Herein, a cocrystal composed of pyrene and 4-(1,2,2-triphenylethenyl)pyridine (Py/TEP) was prepared, which exhibits pure blue fluorescence with a high fluorescence quantum yield of 53.92%. This Py/TEP cocrystal presents photochromic performance. Moreover, Py/TEP cocrystal exhibits reversible luminescent switching upon acid/base vapor and mechanical force. The anticounterfeiting demo based on reversible fluorescence switching has been achieved. Employing Py/TEP as a phosphor, an LED exhibits white emission with CIE coordinates of (0.28, 0.36).