Research On The Device Mechanism Of New Water/alcohol Soluble Cathode Interface Modification Materials For Organic Solar Cell

As the third generation of thin-film solar cells,organic solar cells have many advantages compared with traditional photovoltaic technologies,such as low manufacturing cost,flexible device morphology,and can be integrated into a variety of products and applications.The development of organic photovoltaics is of great significance to the fields of renewable energy and sustainable development.In this paper,the water/alcohol-soluble cathode interface material PDIN is used as the doping modification object,and the modified composite interface layer is spin-coated on the PM6:BTP-e C9 active layer to improve the conversion efficiency of photovoltaic devices:1.The effects of different nitrogen-doped graphene（NG）doping levels on photovoltaic device performance,including enhancement of conversion efficiency and stability,were explored.Disperse nitrogen-doped graphene with different mass ratios in PDIN solution to form PDIN+NG composite material,which is spin-coated on the surface of active layer PM6:BTP-e C9,and a large number of experimental links are optimized,and the device efficiency is finally increased from the initial 14.83%.increased to 15.51%.At the same time,the photocurrent density test was used to further understand the dynamic process of excitons in the device.It was found that the PDIN+3%NG device can absorb photons more effectively than the basic device,and the exciton dissociation rate is also higher.At the same time,through the analysis of the dark current curve,it can be seen that the optimized device in the low-voltage reverse bias region has high parallel resistance characteristics and excellent hole-blocking ability;while in the high-voltage region,it shows the nature of small series resistance,It shows that the device interface contact has been improved.According to the analysis of the light intensity dependence of J_SC and V_OC,it can be seen that the application of composite material PDIN+3%NG at the cathode interface can inhibit molecular recombination to a certain extent.In addition to the adjustable electrode work function of the interface material,based on the linear voltammetry scanning method and other characterization methods,it is determined that the electrical conductivity of the composite material formed after doping is improved,and the electron mobility is further increased.In addition,the device morphology was characterized by water contact angle and AFM and SEM imaging techniques,and it was found that the composite interface material can improve the film’s surface morphology and optimize the device interface contact.2.Nitrogen-doped multi-walled carbon nanotubes（NMWCNT）doping studies on PDIN were next carried out.PDIN+NMWCNT was spin-coated on the PM6:BTP-e C9active layer,and the photovoltaic device with PDIN+2%NMWCNT as the cathode interface layer showed better photovoltaic characteristics than the basic device,and the efficiency increased to 15.26%.The same experimental conclusion as above was obtained by the same characterization method.Moreover,due to the application of the composite material PDIN+2%NMWCNT,the charge collection efficiency of the device is also improved.