Fig. 2
The phosphorescence spectra and corresponding time-resolved decay curves for the six compounds. a The normalized room temperature phosphorescence spectra of CS-CH3O, CS-CH3, CS-H, CS-Br, CS-Cl, and CS-F in crystal state. b Time-resolved PL-decay curves for their room temperature phosphorescence in crystal state. c The normalized low temperature (77 K) phosphorescence spectra in dichloromethane solution, concentration: 10−5 M. d Time-resolved PL-decay curves for their low temperature phosphorescence in dichloromethane solution, concentration: 10−5 M. e The proposed mechanism for organic persistent RTP: the strong π–π interaction could decrease the radiative transition (kP) and non-radiative transition (kTS) from T1 to S0 state, thus achieving the persistent room temperature phosphorescence
