Preparation And Functionalization Of Long-Lived Room Temperature Phosphorescent Polymeric Materials

Room temperature phosphorescent materials have unique advantages in the fields of biological imaging,information storage,sensor equipment,organic lightemitting diodes,and data encryption owing to outstanding features of persistent luminescence.The polymer-based room temperature phosphorescent materials are quite suitable for manufacturing and processing organic phosphorescent devices with complex shapes due to the excellent features of polymers,such as elasticity,flexibility,film-forming ability,and transparency.However,polymer-based phosphorescent materials with high quantum yield and long lifetime are rarely reported.In this dissertation,a novel strategy of constructing room temperature phosphorescent materials utilizing three-dimensional network structure polymer was proposed and a variety of new polymeric long-lived room temperature phosphorescent materials were developed.The room temperature phosphorescence performance of these materials was effectively improved based on the rigid environment provided by the three-dimensional network matrix for the doped luminescent molecules.1.High efficiency and long-lived room temperature phosphorescent organic films were prepared based on the strategy of dense three-dimensional network epoxy matrix which could effectively suppress the non-radiative attenuation of organic phosphors:The room temperature phosphorescent polymer films were prepared by doping the phosphorescent molecules into the dense three-dimensional polymer network.The dense three-dimensional network was used to suppress the non-radiative decay of phosphorescent molecules.Finally,an ultra-long lifetime of 2.28 s and a phosphorescence quantum yield of up to 8.35%were achieved in these films.The control experiments proved that the dense polymer matrix could effectively prevent the diffusion of oxygen,which avoided the quenching of phosphorescence by oxygen.The universality of this strategy was also verified.2.Multifunctional polymer films with photochromic,fluorescent,and phosphorescent properties were prepared with controllable three-dimensional network structure epoxy polymer as the matrix and photochromic molecules as the doping molecule:The multifunctional films were prepared by doping photochromic molecule naphthopyran into the epoxy matrix.By adjusting the concentration of curing agent and curing temperature,the polymer network structure and the binding effect of the polymer on naphthopyran molecules were regulated,achieving controlled transition from photochromic properties to fluorescence-room temperature phosphorescence dual luminescence properties.The experimental results showed that the rigid network matrix could inhibit the ring opening and vibration of naphthopyran molecules.The theoretical calculation proved that the energy level of naphthopyran molecule in closed loop state was more favorable to emission fluorescence and room temperature phosphorescence.3.Enhanced room temperature phosphorescent polymer films by intermolecular donor-acceptor complex were prepared with the dense threedimensional network structure epoxy polymer as matrix and the intermolecular electron donor-acceptor complex as the doping guest:The electron-rich molecule 1,5,7-triazabicyclo[4.4.0]dec-5-ene(TBD)and the electron-accepting molecule 3,3-diaryl-3H-naphtho[2,1-b]pyrans(Naph)were selected to fabricate intermolecular donor-acceptor complex.The donor TBD and the acceptor Naph formed intermolecular donor-acceptor complex in the dense polymer network,emitting ultra-long room temperature phosphorescence with a lifetime of up to 300 ms.The URTP intensity of the TBD-Naph co-doped film increased by 20 times compared with the film doped only with Naph.The photophysical mechanism of enhancing URTP by intermolecular donor-acceptor complex were explored and clarified thoroughly by detailed experiment and theoretical calculations.4.Visible light excited polymeric long-life room temperature phosphorescent organic films were prepared with the dense three-dimensional network structure epoxy polymer as the host matrix and the biphenyl derivatives with oxygen anion substituents as doping guest molecules:The polymer films were prepared by codoping with TBD molecules and 1,6-diphenylphenol molecules.The basic molecule TBD turned the phenolic hydroxyl group of diphenylphenol into an oxygen anion substituent,so that the room temperature phosphorescence of the film could be effectively excited by visible light.The oxygen anion substituent enhanced the synergistic effect of ?-? conjugation and n-? conjugation,which endowed diphenylphenol with higher intersystem crossing efficiency.