Preparation And Doping Of Hole Extraction Layer For Inverted Planar Perovskite Solar Cells

Organic-inorganic halide perovskites solar cells have garnered increasing attention in recent years due to the dramatic rise in power conversion efficiencies(PCEs).Perovskite crystal(CH₃NH₃Pb X₃,X is halogen)was synthesized by Miyasaka group in 2009 with methyl amine and lead halide as the light absorber for the solid-state thin film solar cell for the first time,with the highest conversion efficiency(PCE)reaching 3.80%.At present,the PCE of perovskite solar cells has been increased to 23.30%,and the photoelectric conversion efficiency has soared in just a few years,indicating a promising application prospect.Therefore,it has become one of the research hotspots of new solar cells.The realization of theoretical limiting power conversion efficiency in perovskite solar cells requires better understanding and control of the basic loss process occurring in the perovskite layer and the internal interface of the device.One of the most significant challenges is the elimination of charge recombination centers near grain boundaries.Hole transport material is one of the important components of efficient perovskite solar cells.In perovskite solar cells,in order to achieve higher photoelectric conversion efficiency of perovskite solar cells,hole transport layer is generally used to block electron transport,enhance hole transport and prevent chemical reaction between perovskite active layer and electrode.The hole transport materials of perovskite are mainly divided into organic and inorganic categories.Compared with traditional organic hole transport materials,although the photoelectric conversion efficiency of perovskite solar cell based on inorganic hole transport materials is lower than the photoelectric conversion efficiency of perovskite solar cell based on organic hole transport materials,but inorganic hole transport materials usually has good chemical stability,high hole mobility and low preparation cost,therefore,the development and application of cheap and stable inorganic hole transport materials is of great significance for producing low cost and high stability perovskite solar cells.In this study,we use lead(Pb)and lithium(Li)co-doped nickel oxide,the photoelectric conversion efficiency of perovskite solar cell device based on co-doped nickel oxide is from15.40%to 17.02%.We found that doping of lead and lithium improves the work function of nickel oxide,and it is better matched with the valence band energy level of perovskite,this is advantageous for the hole extraction and transmission,thus reduce charge recombination,at the same time,the doping of lead and lithium improve the electrical conductivity of nickel oxide.We prepared uniform and dense nickel oxide film doped with lead and lithium by simple solution method,and the film had no effect on the morphology of perovskite film.Perovskite solar cell devices based on nickel oxide hole transport layer doped with lead and lithium have higher photoelectric conversion efficiency.