Nanometal Hybridization And Photoelectric Conversion Efficiency Of Polymer Solar Cells

Polymer solar cells?PSCs?have gained tremendous developments in the past decade for their virtues,including light weight,flexibility,low cost,and easy fabrication processes.However,its low power conversion efficiency?PCE?,high toxic and pollutional processing solvents and bad device stability greatly hinder the commercialization of PSCs.In order to solve these problems,and promot the commercialization of PSCs,we utilize the localized surface plasmon resonance effect?LSPR?of metallic nanoparticles to improve the PCE,replace toxic solvents with green solvent to process active layers of PSCs,and utilizing solution processed CuOx as hole transport layer to improve the stability of device.The detailed contents are listed as following:?1?PSCs can be enhanced by the localized surface plasmon resonance effect?LSPR?of metallic nanoparticles for improving the light absorption of active layers,thus enhancing the photovoltaic performances.In this thesis,Ag nanoparticles,core-shell Ag@SiO₂ nanoparticles and tri-angle Ag nanoplates with different LSPR wavelength are synthesized.Based on the solution processed WO₃ hole transport layer,Ag nanoparticles,core-shell Ag@SiO₂ nanoparticles and tri-angle Ag nanoplates are incorporated to the hole transport layers.Because the very thin thickness WO₃ hole transport layer?10 nm?,Ag nanoparticles and core-shell Ag@Si O₂ nanoparticles can protrude the Ag nanoplates,and contact the active materials directly,while,Ag nanoplates embe in the hole transport layers.As results,Ag nanoparticles quench the exictions and decrease the PCE of PSCs greatly,while,the SiO₂ encapsulated Ag@SiO₂ nanoparticles and Ag nanoplates embed in the hole transport layers improve the PCE of PSCs by 13.2% and 19.7%,respectively.The improved photovoltaic performances can be ascribed to the enhanced light absorption of active layers by the LSPR effect of metallic nanoparticles.?2?This work report the enhancement of photovoltaic performance of hybrid PSCs by dual-shapes of metallic nano-additives of Ag-nPl and Ag@SiO₂-NPs.Ag-nPl and Ag@SiO₂-NPs are spin-coated on ITO glass and incorporated to PBDTTT-C-T:PC71BM active layer,respectively,to utilizing the LSPR effects to enhancing the light absorption of the active layer in polymer solar cells.With the full visible light sensitization by the incorporations of both Ag-nPl and Ag@SiO₂-NPs,the polymer solar cell obtained the optimal photovoltaic performance with maximum PCE of 8.46%,and Jsc of 17.23 mA/cm2.According to the systematic characterizing,the enhanced Jsc is ascribed to the improved light absorption of active layer by the incorporation of metallic nanoparticles.Importantly,the methodology of multiple shape combination of metallic nano-additives improves the photovoltaic performance of PSCs much effectively comparing single shape method,which will be the new way to increase the efficiency of PSCs.?3?One of factors that hinder the commercialization of PSCs is that the processing solvents of active layer are usually high toxic and pollutional.So it is meaningful to look for environment friendly green solvent to process active layers of PSCs.Based on the Hansen parameters of P3 HT and PC71 BM,we select environment friendly ethyl benzenecarboxylate?EB?as the additive of toluene?TL?solution.As a result,with the optimized EB concentration of 2 vol%,P3HT:PC71BM films can obtain the ideal interpenetrating network structure,which leads to best PCE of 4.82%.Therefore,it can be believed that EB can effectively regulate the micro-morphology of active layers,and the EB-TL solvents can be the processing solvent for future PSCs commercialization.Besides,we analysis the reasons that EB in TL can regulate the micro-morphology of P3HT:PC71BM film.?4?The acidic PEDOT:PSS layer is known to be corrosive to the ITO electrode and would degrade the device lifetime.Utilizing easy fabricated solution processing method to fabricate CuOx hole transport layer,good photovoltaic performances and better device stability are achieved.So the CuOx hole transport layer processed by this method can replace the PEDOT:PSS and apply to the fabrication process of future commercialization of PSCs.According to the research contents,the innovations of this thesis are as following: according to the structure of metallic nanoparticles,avoide causing excitons quenching and effectively utilize the LSPR effects of metallic nanoparticles to enhance the PCE of PSCs without,select environment friendly EB as the additive of TL solution to effectively regulate the micro-morphology of active layer and realized good photovoltaic performances,utilize easy fabricated solution processing method to fabricate CuOx hole transport layer,as results,good photovoltaic performances and better device stability are achieved.