Doping Studies Of Perovskite Thin Film Solar Cells

The organic-inorganic hybrid perovskite solar cell has experienced a leap development and its photoelectric conversion efficiency has changed from the initial 3.8% to the current 22.1% since 2009.The greatest advantage of the perovskite material is its high absorption coefficient and excellent ambipolar carrier transport properties.Ideally,the hole transport layer can only transmit the hole,and the dense layer can only transmit electrons.When the light irradiation light anode to perovskite solar cell,perovskite as the light absorbing layer absorbs photons and perovskite is excited.The electron is transferred to the dense layer,and the hole is transmitted to the hole transport layer.Based on the difference of the propagation direction of electron and hole,the electron concentration gradient and hole concentration gradient are generated at the interface between dense layer and perovskite layer,hole transport layerand perovskite layer.In this way,electrons and holes diffuse toward the dense layer and the hole transport layer,respectively.However,the electrons and holes in the perovskite layer have a certain degree of recombination,which leads to the loss of photogenerated carriers.If the perovskite layer is made of p-n or p-i-n structure,when the sun shines on the p-n junction or p-i-n junction,the electric field in the p-n or p-i-n junction will separateelectron hole pair(exciton)into electrons and holes and transmit to the cathode and anode.The photogenerated electrons flow to the N zone,and photoholes to flow to the P zone,so it will greatly reduce the recombination of photogenerated carriers in the perovskite layer.So it will improve the photoelectric conversion of organic inorganic halide perovskite solar cell efficiency and the performance of the solar cell.As Yanfa Yan reported,approaches for doping organicinorganic CH3NH3PbI3 halide perovskite solar cell mater ials are investigated by density-functional theory calculations of the extrinsic doping properties of CH3NH3PbI3.Results reveal that p-type CH3NH3PbI3 halide perovskites can be realized by incorporation of some group IA,IB,or VIA elements such as Na,K,Rb,Cu,and O at I-rich growth conditions.They further show that n-type CH3NH3PbI3 halide perovskites are more difficult to realize due to the formation of neutral defects or compensation from intrinsic point defects.The results suggest that nonequilibr ium growth conditions and/or processes may be required to produce n-type CH3NH3PbI3 halide perovskites.In this paper,perovskite thin films were prepared by doping different concentrations of KI,KI and different concentrations of RbI in PbI2 and MAI precursor solution for P type doping.Using aone-step process and adding chlorobenzene to prepare MAPbI3 layers which dope different concentrations of KI,KI and different concentrations of RbI.Perovskite thin films were characterized by surface SEM,cross section SEM,EDX and XRD test.The prepared MAPbI3 perovskite solar cells were characterized by current-voltage test(J-V test)and IPCE test.The test results show that the doping of KI,KI and different concentrations of RbI are not conducive to the conversion efficiency of perovskite solar cells.