Study On The MAPbI₃ Film Of Perovskite Solar Cells

With the continuous development of the society and the rapid economic growth,the increasing demand for energy,solar cells have drawn extensive attention as green and environmental energy.Since MAPbI₃ has been reported as light-absorbing material for solar cells in 2009.Perovskite solar cells?PSCs?have attracted extensive attention worldwide in less than a decade owing to its low cost,simple manufacturing process,and high photoelectric conversion efficiency.The quality of perovskite films is the key of all types of PSCs.In this paper,the quality of perovskite films was improved by optimum preparation process,modification and doping.The device performance,surface morphology,crystallinity and light absorption properties were extensively studied.The main research contents and results are as follows:?1?The MAPbI₃ perovskite film was generated by two-step with the PbI₂?DMSO?dissolved in DMF as the precursor solution.The performance of the cell was greatly improved.The perovskite film was uniformly distributed and closely packed,with larger grain sizes,and better contact between different grains.Furthermore,no obvious structural defects observed in the film.Thus the result of enhanced light absorption was achieved.The perovskite films exhibited good light trapping performance.The photoelectric conversion efficiency,open circuit voltage and short circuit current density of the cell were increased to 12.05%,1.06 V and 21.5 mA/cm²,respectively.?2?The exfoliated graphite phase carbon nitride?E-g-C₃N₄?particles were further used to modify the perovskite film.The perovskite boundary gap could adsorb E-g-C₃N₄ particles spontaneously due to hydrogen bonding and prevented hole transport materials?HTMs?from infiltrating into the perovskite layer.Through the optimization of E-g-C₃N₄ concentration,the photoelectric conversion efficiency,fill factor,open circuit voltage and short circuit current density of the resulting cell were increased to15.8%,1.1 V,23.2 mA/cm²,respectively.The photoelectric conversion efficiency was24%,which was significantly higher than that of the reference cell.This was attributed to the fact that the interface of perovskite film and E-g-C₃N₄ has a stronger hole extraction ability,a lower recombination probability and a longer carrier lifetime.?3?MA-FA doped perovskite layer was obtained by immersion method.The highest photoelectric conversion efficiency of the device was 15.2%,which was 25%higher than the reference cell.The open circuit voltage and short circuit current density of the cell were increased to 1.02 V,23.5 mA/cm²,respectively.Furthermore,the short-circuit current was improved obviously without reducing the open circuit voltage.The doping of FA⁺has greatly improved the surface morphology and crystallization of perovskite films.This not only benefits for the transmission of electrons and holes,but also has a desirable effect bandgap width.