| In recent years,organic long persistent luminescence materials have received widespread attention due to their unique luminescence properties,and they have potential applications in the fields of optical display,biological imaging,information encryption,and sensing.Polymer materials are more popular due to their excellent processability and flexibility,but there are few reports on polymer long persistent luminescence materials with external stimulus response behavior.This thesis focuses on the development of polymer persistent luminescence materials with light stimulus response behavior,and explores its internal luminescence mechanism and potential applications.The main research contents are as follows:(1)Carbazole-based excitation-dependent polymer long persistent luminescence material.Carbazole is the star molecule in optoelectronic materials.Two carbazole derivatives were grafted onto heteroatom-rich polyphosphazene to obtain P2 and P4 molecules.By doping them into the polyvinyl alcohol(PVA)film,the polymer long persistent luminescence material with excellent luminescence performance in the atmospheric environment was successfully prepared.Interestingly,in the atmospheric environment,the afterglow color of films have an excitation-dependent property.By changing the excitation wavelength,the afterglow color of the materials can be adjusted from blue to green.At the same time,based on the formation and destruction of the hydrogen bond interaction between the PVA chain and the molecule,a dynamic cycle of excitation-dependent long persistent luminescence is realized.Based on its unique optical phenomenon,we apply it to the field of information encryption.(2)Molecular engineering strategy to realize low-cost,good universality polymer long persistent luminescence materials.The current methods for developing new organic long persistent luminescence materials are mainly synthesis of new chromophore molecules and crystal engineering.However,there are great challenges in the preparation of new chromophore molecules and the use of crystalline materials.We have prepared a series of radiation-dependent polymer long afterglow materials through molecular engineering between small organic molecules and polymer matrix.Under ultraviolet light irradiation,energy transfer occurs between triplet oxygen and triplet excitons in the film,and then triplet oxygen becomes excited singlet oxygen,which reduces phosphorescence quenching,so the afterglow growth process of the material can be observed with the naked eye during the irradiation.Taking the P2-M2 film as an example,its phosphorescence intensity,lifetime,afterglow brightness and quantum yield increased by 155,262,414 and8 times after irradiation.We also explored its potential applications in the field of information storage.The method has high efficiency and good universality,and provides a novel strategy for preparing low-cost polymer long persistent luminescence materials.(3)Polymer long persistent luminescence material with multiple stimulus response behavior.We use the polymer synthesized in the previous work as the matrix,and doping pyrene and its derivative into the polymer according to different concentrations to make a variety of films.Interestingly,the afterglow color of the film exhibits a concentration-dependent characteristic.After excitation at 254 nm UV lamp,the afterglow color is blue at low concentration(0.001mg/ml),and red at high concentration(1mg/ml).At the same time,the afterglow color of the film also exhibits excitation-dependent characteristics.With the excitation wavelength increases,the afterglow color has a red shift.More importantly,the afterglow of the intermediate concentration(0.1mg/ml)film shows a clear time-dependent characteristics,which can gradually change from orange to green This kind of polymer long persistent luminescence material with multiple stimulus response behavior has good application prospects in the fields of information encryption and chemical sensing. |
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