Ultrafast Photoexcitation Dynamics Behavior of Hydrogen-Bonded Polyfluorenol

Exciton behavior is crucial to the exploitation of light-emitting conjugated polymer(LCPs)for optoelec-tronic devices.Singlet excitons are easily trapped by the intrinsically defect structures.Herein,we set a polyfluorenol(PPFOH)as an example to systematically investigate its photophysical behavior to check the role of defect structures in LCPs.According to time-resolved photoluminescence analysis,the feature emission peaks from individual chain of PPFOH in diluted DMF solution is effectively avoided the influ-ence of fluorenone formation,but the residual green-band emission at 550 nm is easily observed in the PL spectra of PPFOH dilute toluene solution obtained delay 1.5 ns,confirmed the formation of"guest"physical aggregation-induced defect structure.Remarkably,efficient and ultrafast energy transfer from in-dividual chain to defect structure is observed in PPFOH films.Interestingly,the efficient energy transfer happened for the film obtained from DMF solution(200ps)than those of toluene ones(600ps).Mean-while,compared to relatively stable green-band emission in PPFOH film from toluene solution,red-shifted emission peak(11 nm)of PPFOH film from DMF solutions exposed to saturated DNT vapor also confirmed their different aggregation-induced green-band emission.Therefore,this aggregation defect structures are influenced on the photophysical property of LCPs in solid states.