Revealing The Internal Heavy Chalcogen Atom Effect On The Photophysics Of The Dibenzo[A,J]Phenazine-Cored Donor-Acceptor-Donor Triad

A new twisted donor-acceptor-donor (D-A-D) multi-photofunctional organic molecule comprising phenoselenazine as the electron donor (Ds) and dibenzo[a,j]phenazine (DBPHZ) as the electron acceptor (A) has been developed. The developed selenium-incorporated D-A-D compound features multi-color polymorphism, distinct mechanochromic luminescence, chemically-stimulated luminochromism, thermally-activated delayed fluorescence, and room-temperature phosphorescence. The internal heavy atom effect on the photophysical properties of the D-A-D system has been investigated through a comparison with the physicochemical properties of a previously developed sulfur analogue and a tellurium analogue.