Interface Engineering And Nickel Oxide Optimization In Perovskite Solar Cells

Perovskite solar cells(PSCs)have attracted great attention from researchers in recent years,owing to their easy fabrication,low cost and great potential for development.In the past ten years,the efficiency of PSCs has rapidly increased from 3.8%in 2009 to 25.5%today.The photoelectric performance and stability of perovskite solar cells are current research hotspots.In this study,interface engineering of the perovskite active layer and nickel oxide optimization are used to prepare planar perovskite solar cells with high efficiency and high stability.(1)Previous research results show that the iodides of alkane-based cations and aromatic-based ammonium cations can passivate defects in perovskite batteries,reduce non-radiative carrier recombination and improve the photoelectric properties of perovskite films.However,a 2D perovskite layer PEA2PbI4 will be formed after thermal annealing,which will reduce the thermal stability of the device.In this study,we propose the use of a novel two-dimensional(2D)perovskite material based on a large size phenyl-formamidinium iodide(PFAI)to act as surface "patches" to reduce charge recombination and improve the quality of perovskite film.The study indicates that PFAI can enhance the photovoltaic performance and thermal stability simultaneously.By optimizing the concentration of the PFAI solution,we obtained a champion efficiency of 21.38%on rigid PSCs.Flexible perovskite solar cells have a wide range of application prospects.Due to its low weight,mechanical durability,compatibility with different curved surfaces,and cost-effective fabrication,the performance of flexible perovskite devices has also received extensive attention.The champion efficiency of flexible PSCs passivated by PFAI reaches 19.89%,and can maintain 70.4%of its initial PCE after 1000 hours at 85℃.(2)Previous studies have shown that the choice of nickel oxide as hole transport material in the planer inverted perovskite solar cells,has the advantages of stable performance and low cost,but low-temperature synthesized nickel oxide has problems such as low conductivity and high defect density,which limit the improvment of the efficiency of perovskite solar cells.In order to improve the performance of the device,we have carried out a series of modifications such as europium doping,copper doping,and cobalt doping on the nickel oxide layer.It was found that when the Eu doping concentration in nickel oxide was 0.5 mol%,the morphology of the nickel oxide film was improved,the defect density was reduced,the interface recombination was reduced,the conductivity was enhanced,and the best efficiency of the device was 20.58%.