Fabrication Of High-efficiency Perovskite Solar Cells By Interface Engineering And Electron Transport Layer Dopin

Perovskite materials have attracted much attention from researchers in recent years due to their long carrier mobility,adjustable bandgap,outstanding light absorption coefficient and low raw material cost.In the past decade,the photoelectric conversion efficiency of single-junction perovskite solar cells has increased from 3.8%to 25.8%.The preparation process of perovskite solar cells is simple,and the efficiency is comparable to that of silicon-based solar cells.Therefore,it has a strong commercial market prospect.However,long-term stability is an obstacle to the commercial application of perovskite solar cells.External encapsulation can largely avoid the invasion of oxygen and water to the cell,but the quality of the perovskite film itself is the key factor to determine the performance of the cell.Perovskite films and charge transport layer films prepared by solution method have many defects in the bulk phase and surface.The existence of these defects will lead to non-radiative recombination of photogenerated carriers,resulting in loss of efficiency and decrease of device stability.Therefore,in order to improve the photoelectric conversion efficiency and stability by passivation defects,this paper chooses interface modification and electron transport layer doping strategy to prepare perovskite solar cells.The specific research contents are as follows:（1）Perovskite active layer was prepared by one-step method in this article.The organic metal salt magnesium benzoate was used to modify the perovskite layer/hole transport layer interface.The effects of different modification concentrations on the device were systematically studied.The non-radiative recombination is effectively suppressed by synergistic passivation of the A-site and X-site of the perovskite film.According to this scheme,the efficiency of the prepared perovskite solar cells has been greatly improved,from19.94%to 22.24%,and can still maintain 90%of the initial efficiency after 30 days of storage in dry air.（2）Based on the use of magnesium benzoate modified perovskite layer/hole transport layer interface,the electron transport layer was optimized by doping.Ti O2 was selected as the electron transport layer,and different concentrations of Fe³⁺was doped in Ti O2 solution.According to this scheme,the defect concentration of the electron transport layer is reduced,which can better extract the photogenerated electrons generated by the perovskite absorption layer.The device was simultaneously doped with the electron transport layer and modified at the interface.Under the dual optimization strategy,the perovskite solar cell with a photoelectric conversion efficiency of 22.89%was prepared,and had a good stability.