Visible light-activated optical switching behaviors of tetra-/triphenylethene-dithienylethene-BF2bdk triad

Developing new visible light-triggered fluorescent molecular photoswitches is highly desirable for potential application in the fields of photoresponsive optoelectronics and photopharmacology. In this contribution, two novel tetra-/triphenylethene-dithienylethene-BF2bdk triads (TDB1 and TDB2) have been designed and prepared by appending tetra-/triphenylethene and BF2bdk moieties at the termini of dithienylethene unit. Before irradiation with blue light at 460–470 nm, they showed an intense emission in solution and in the PMMA film state, suggesting that the AIE effect of tetra-/triphenylethene was inhibited, and functioned only as electron-donating groups. Moreover, upon alternating irradiation with blue/NIR light, TDB1 and TDB2 displayed effective fluorescent switching behaviors and NIR photochromism in toluene and the PMMA film. Therefore, they would be utilized as novel visible light-triggered switches integrated in smart optoelectronic materials. The DFT calculations further validate the differences for their optical properties in the experiments.