Preparation Of Perovskite Solar Cell By PbI₂·DMSO Complex Precursor Solution And Research Of Its Photovoltaic Performance

Ammonium halide perovskite solar cell has attracted wide attention in recent years because of its tunable band gap,excellent electron-hole diffusion lengths,high absorption coefficient and good tolerance to defects,which becomes the focus of academic research.Perovskite absorption layer is an important component of perovskite solar cells,and the chemical composition,preparation process,concentration of precursor solution has influence on the microstructure of absorption layer and photovoltaic properties of solar cells.In this thesis,the preparation of Br or Cl doping mixed halide perovskite thin film was based on the intramolecular exchange of DMSO molecules intercalated in PbI2(PbI2 DMSO complex)with CH3NH3X(X = I、Br、Cl),The system studied the effects of composition of conversion solution CH3NH3X(X = I、Br、Cl)on the crystal phase,optical absorption,morphology,chemical composition of Br or Cl doping perovskite films and photovoltaic properties of Br or Cl doping perovskite films were studied.The high-concentration of PbI2·DMSO complex precursor solution in DMF was successfully prepared by batch-wise addition of PbI2 and DMSO,repeated procedure of PbI2 dissolution and DMSO addition,keep PbI2 excess to suppress PbI2-DMSO2.The crystal phase,optical absorption,morphology and chemical composition of PbI2 DMSO complex thin film and CH3NH3Pbl3-xBrx thin film were compared with different concentrations of PbI2· DMSO complex precursor solution,and the corresponding planar perovskite solar cell was assembled.TiO2 nanorod array perovskite solar cells were prepared by controlling the molar ratio of Pbl2 and DMSO with confirmed stirring time.The effects of molar ratio of PbI2·(DMSO)x complex precursor solution on the crystal phase,surface morphology and optical absorption of perovskite absorption layer were analyzed.The results showed that the perovskite films based on the conversion solution of CH3NH3X contains 5%CH3NH3Br or 15%CH3NH3Cl exhibited the best photoelectric conversion efficiency(PCE)of 13.2%and 13.5%.The 1.7 mol dm-3 PbI2 DMSO complex precursor solution in DMF was successfully prepared by the cycle of PbI2-dissolving and subsequently DMSO-adding.The high-thickness CH3NH3Pbl3-xBrx thin film with the feature of full-coverage and large-grain was obtained using 0.465 mol·dm-3 isopropanol solution of the methylammonium halide mixture was converted on the top of the PbI2·DMSO thin film,and with the increase of the PbI2 DMSO complex precursor solution concentration from 1.3 mol ·dm-3 to 1.5 mol·dm-3、1.7 mol·dm-3,the corresponding thickness of CH3NH3PbI3-xBrx increase from 337 nm to 446 nm and 529 nm.The planar perovskite solar cell exhibited the best PCE of 4.69%,11.19%,12.83%at the relative humidity of 50～54%.When the molar ratio of PbI2 to DMSO is 1:2,the PCE of the corresponding TiO2 nanorod array perovskite solar cells achieved the best PCE with 13.82%.