Research On The Performance Of Carbon-based Perovskite Solar Cells

Due to the characteristics of high light absorption coefficient,adjustable band gap,low defect density and low material cost,perovskite has become a hot spot in the field of solar cell research.The PCE has increased from 3.8%to 25.5%,which shows a rapid development.However,the perovskite solar cells use precious metals such as Au and Ag,which are not only high in cost but also more complex in preparation process,making the devices with this structure difficult to be put into commercial production channels.carbon material has good electrical conductivity and its work function is close to that of gold,so it is a suitable material to replace precious metal in perovskite solar cell.Carbon-based perovskite solar cells have the advantages of low cost,simple process and flexible devices,but the photoelectric conversion efficiency is lower than that of metal electrode cells.Based on the preparation of carbon-based perovskite solar cells by screen printing,the performance of the transfer layer is optimized to improve the photoelectric conversion efficiency and working stability of the device.The research contents include:（1）Cs_0.05FA_0.87MA_0.08Pb(Br_0.12I_0.88)₃ was used as perovskite material,and the films were prepared by two-step spin coating method.By changing the preparation process of the film,the effects of changing the concentration of perovskite precursor solution and the spin coating process on the film quality and the photoelectric performance of the device were investigated.The prepared films were characterized by,steady-state fluorescence spectroscopy,UV-visible absorption,scanning electron microscopy AND,and the surface morphology of the films was observed.The crystal grains of the films with a concentration of 1.2M were larger.The film was used as the active layer in ITO/Sn O₂/Cs_0.05FA_0.87MA_0.08Pb(Br_0.12I_0.88)₃/C structure,and the conversion efficiency was 12.72%.After optimizing the rotating speed and adjusting the thickness and uniformity of the film,the efficiency is increased to 12.8%.（2）The carbon based perovskite solar cell without holes-transport layer was prepared.A Na Cl layer is spun on the electron transport layer and annealed.SEM was used to observe the surface of perovskite films,and it was found that there were Na Cl particles between the grains,which would be mixed with Na Cl during the growth of perovskite grains.By controlling the concentration of Na Cl aqueous solution,the influence of different densities of Na Cl on the film was explored.J-V curve,dark current curve,interface charge and other data of the device were tested.The comprehensive analysis showed that 2mg/m L Na Cl solution improved the performance of the device.The open-circuit voltage is increased from 0.88 V to 0.91 V,and PCE is increased from 13.79%to 14.38%.（3）P3HT was used as the hole transport layer in the carbon based perovskite solar cells.By adding DIO to P3HT,the influence of the additive DIO on the performance of the hole transport layer and the device was investigated.It was found that the surface roughness of the film with the additive DIO was reduced,the surface morphology was changed,and the film quality and smoothness were improved.The carrier mobility of the single-carrier device was tested,and the hole mobility was improved with the addition of DIO.The efficiency of perovskite solar cells increased from 14.06%to 15.11%.