Preparation And Interfacial Passivation Of Organic-inorganic Hybrid Perovskite Solar Cells

Perovskite has become a hot research direction in the field of solar cells in recent years due to their high absorption coefficient,low crystalline energy barrier,adjustable band gap,and high defect tolerance.However,since the perovskite solar cells are generally prepared by the solution method,the imbalance of crystal growth during annealing means that there will be a large number of defects in the perovskite crystals,and the defects will cause non-radiative recombination of carriers,thereby reducing the open circuit voltage of the device and directly affecting Device efficiency.Therefore,in the process of device preparation,obtaining high-quality perovskite crystal films and reducing surface defects are the key to reducing non-radiative recombination of carriers and improving device performance.This thesis takes the FACsPbI₃ system perovskite solar cell as the research object,prepares a high-performance perovskite solar cell device through the one-step process control,and studies the surface defect passivation theory of the perovskite solar cell.The main work and conclusions are as follows:We first improved the preparation process of the perovskite light-absorbing layer in the FACsPbI₃ one-step system perovskite solar cell:we explored the three aspects of solvent engineering,spin coating speed,and annealing temperature on the film quality of the perovskite polycrystalline film It was determined that when the solvent ratio V_NMP:V_DMF=8:2,the spin speed was 3500 rpm/min,and the annealing temperature was 120℃,a smooth and smooth perovskite film could be prepared,and finally a device with a photoelectric conversion efficiency of 17.39%was prepared..Then,due to the existence of lead clusters and vacancy defects in the perovskite thin films prepared by the solution method,these defects will lead to non-radiative recombination of carriers and affect device performance.At the same time,surface defects can easily become water adsorption sites and cause the film to decompose.We used mercaptoethylamine hydrochloride to passivate the surface of the perovskite film,and analyzed the passivation mechanism of mercaptoethylamine hydrochloride for defects.The infrared spectroscopy and X-ray photoelectron spectroscopy proved that the mercapto and lead ions passivation of the coordination and finally improved the photoelectric conversion efficiency of the device from 17.23%to 19.42%.The humidity stability of the device was improved.After 352 hours of storage under the relative humidity of 55%,the device efficiency of the control group decreased to 31%of the initial efficiency,while the device efficiency of the experimental group remained at 65%of the initial efficiency.