Preparation And Photovoltaic Performance Of Silver Nanowire Flexible Electrodes And Their Organic Solar Cell Flexible Device

Organic Solar Cells（OSCs）have attracted wide attention from researchers and become a research hotspot in the field of photovoltaics because of its advantages of light weight and low cost,and the ability to combine solution processing with roll-to-roll process to prepare large-area flexible devices.After decades of research and development,the working mechanism of OSCs has been better understood and the preparation process has been further improved.Furthermore,single-junction OSCs exhibit the power conversion efficiency（PCE）of 18%,which show a broad application prospect.Through the previous work,it can be understood that flexible electrode materials are the key to prepare portable wearable electronic devices and flexible solar cell devices.However,disadvantages of the traditional transparent electrode indium tin oxide（ITO）such as brittle,high preparation cost,high temperature preparation and unstable properties limit application of ITO in flexible electrodes.Therefore,finding new flexible transparent electrodes with excellent performance and optimizing the preparation process are the focus of current research in flexible optoelectronic devices.This paper focuses on the optimization of flexible transparent electrodes based on silver nanowires（Ag NWs）and OSCs devices to improve the photoelectric conversion efficiency and flexibility of Flexible Organic Solar Cells（FOSCs）.The research is carried out from the optimization of Ag NWs electrodes to and the preparation and optimization methods of FOSCs devices.The detailed works are as follows:（1）Aiming at the problems of low yield,uneven size distribution of silver nanowires and difficult removal of impurities in the preparation process of silver nanowires,a mild,simple and efficient method for the preparation of Ag NWs was proposed.The obtained Ag NWs have high aspect ratio（～1000）,uniform size distribution（diameter～20 nm）,good morphology and low square resistance of 13Ω/sq.（2）To explore the feasibility of transparent electrodes for FOSCs devices,including the selection of substrate materials,preparation and optimization of electrodes.Biomass bacterial cellulose（BC）and polyethylene terephthalate（PET）were selected as the substrates for the flexible electrodes,and two flexible conductive substrates,PET/Ag NWs/PVA and BC/Ag NWs/PVA electrodes were prepared.PET/Ag NWs/PVA electrodes show a low square resistance of 18.4Ω/sq,high transmittance over 75%in the300-800 nm wavelength range,low roughness and good stability,providing a flexible conductive substrate for FOSCs.BC/Ag NWs/PVA electrode materials exhibit extremely low square resistance（0.4Ω/sq）,low roughness,excellent skin friendliness and excellent stability,making it an ideal electrode material for wearable electronic devices.（3）The preparation of flexible organic solar cell devices was completed,and by continuously optimizing the flexible substrate and device preparation process,the final PBB-TSD:Y6 system flexible device obtained a photoelectric conversion efficiency of5.04%,an open-circuit voltage of 0.61 V,a short-circuit current density of 19.99 m A cm^-2and a fill factor of 40.90%.The efficiency of the PBB-TSD:Y6 based flexible device reaches about 83.4%of the efficiency of the rigid device（6.04%）,and the flexible device based on BC/Ag NWs/PVA electrodes can replace the rigid device to some extent.