Effects Of Electron Beam Irradiation On Polydopamine And Polydopamine/Au Nanoparticles Composite Films

In recent years,the electron beam irradiation?EBI?plays an important role for polymer modification.The requirement of the surrounding medium environment on EBI is not high and not limited to vacuum,and the degree of the surface modification of materials also can be controlled by changing the absorbed dose,which making EBI a highly energy-efficient technique in material modification.When the electron beam energy is transferred to polymer,it can cause the change of the molecular structure,such as ionization,atomic substitution,carbonization and free radical formation..And as result,the chain scissioning and cross linking occurred.Polymer chain scissioning leads to the decrease of molecular weight,and cross linking leads to the increase of molecular weight..Synergic effect of chain scission and cross linking can cause the change of chemical structure as well as crystalline phases,which results in the change in the physical and chemical properties of the polymer.Electron beam irradiation can not only change the chemical structure of polymer,but also can increase the trap charge,and introduce defects into the polymer,resulting in the changes of dielectric properties,electrical conductivity and thennal performance.This topic mainly focused on adjusting the morphology,structure,and the band gap of PDA and PDA/Au nanoparticles?NPs?composites by EBI,in order to enhance carrier transfer and stimulate local surface plasma resonance?LSPR?effect when used in polymer solar cell..The main research content is as follows:1.Dopamine aqueous solution can occur self-polymerization reaction by the use of dissolved oxygen.By this reaction,the PDA film with strong adhesion ability can be formed on the surface of ITO.This first part studied the preparation of PDA film,PDA/Au NPs composite film,and PDA powders,which were used as samples for EBI.2.In the second part,PDA films,PDA/Au NPs composite films and PDA powders were irradiated by electron beam linear accelerator at different irradiation doses ranged from 10 to 150 kGy.The irradiated samples were characterized by FTIR,UV-Vis,SEM,CV,EIS,and TGA.The change in surface morphology,chemical structure,contact angle,molecular weight,the frontier orbitals,and band gap were analyzed.3.Finally,PDA films and PDA/Au NPs composite films modified by EBI were used in interface design and control of polymer solar cells.,The devices with the structure of ITO/PDA-ZnO/PTB7:PC71BM/MoO₃/Al and ITO/PDA-Au NPS-ZnO/PTB7:PC7iBM/MoO₃/AI were fabricated.Photovoltaic performance was measured and the effect of EBI on the enhancement of carrier transfer and the excitation of LSPR were discussed.It indicated that the solar cells with low dose electron beam irradiated PDA thin film modified ZnO electron transport layer had improved open circuit voltage and fill factor,but low short circuit current density;The solar cells with 100 kGy electron beam irradiated PDA film modified ZnO electron transport layer had greatly improved short circuit current density and its efficiency reached a maximum value.PDA/AuNPs composite film modified PTB7:PC71BM solar cells did not achieve the desired results.EBI can play an important role in the enhancement of carrier transport.However,its role in enhancing LSPR needs to be further explored.