“Vibration induced emission” (VIE): <italic>N</italic>,<italic>N</italic>′-disubstituted- dihydrodibenzo[<italic>a</italic>,<italic>c</italic>]phenazines dual fluorescent mechanism

Abstract

In serendipity, N,N′-disubstituted-dihydrodibenzo[a,c]phenazines was discovered to exhibit intriguing photophysical properties including dual fluorescence, large Stokes shift and responsiveness to ambient conditions (polarity, viscosity, etc.), which inspired us to take in-depth research into it. Upon investigations on temperature dependent steady-state spectroscopy, nanosecond time-resolved spectroscopy, femtosecond dynamics and computational simulation of the reaction energy surfaces, we verified that the red emission and its extremely large Stokes shift originate from the bending to planarity motion of benzo[a,c]phenazines moiety and coined this novel mechanism as "vibration induced emission" (VIE). Hence, these phenazines are capable of developing single molecular color tunable materials by affecting the vibration of the molecules, which provides a new paradigm en route to developing versatile materials for photoelectric devices and panel displays.