Diagnosis Of GaAs Solar Cell Via Electroluminescence Imaging And Equivalent Circuit Modeling

Solar energy is an important clean and renewable energy source.As the key device to convert solar energy into electricity,solar cells are the key to develop and utilize solar energy.The defects in solar cell strongly influence the efficiency that we need.Therefore,it is of great significance to analyze the defects for the efficienc.Spatially resolved electroluminescence(EL)images can directly detect the nonuniformity and defect of solar cells.Combined with the two-dimensional equivalent circuit model,the defect characteristics of solar cells and the influence of the defect can be well studied.This dissertation measured the EL images of a Ga As solar cell with different current density,and then established a two-dimensional distributed model to simulate the J-V curve and the EL distributions of the solar cell under dark conditons.Then the effects of resistance parameters on the solar cell and the influence of different defect kinds on EL distributions were discussesd.A method to determine the type of solar cell defects based on the connection between the EL loss at the defect point and the injected current was proposed.The main work and research content are as follows:1)Experiments were carried out to measure J-V relationships,EL response spectra,EQE spectra,and EL images of the Ga As solar cell under different injection currents.Based on the Ga As solar cell structure,a two-dimensional equivalent circuit model of a Ga As solar cell was established.The meaning of each device parameter of the circuit model and the relationship with the actual battery parameters were described.2)The compilation of the circuit netlist was completed,and simulated by Hspice.The correctness of the two-dimensional equivalent circuit model was proved.Moreover,the parameters can be extracted form the two-dimensional equivalent circuit model.The influence of three different resistance parameters on the J-V relationship and EL distribution of solar cells under dark conditons.3)The effect of different types of defects on the EL distribution and voltage distribution under different currents was analyzed by the experiment results and simulation results.A method to determine the type of solar cell defects based on the connection between the EL loss at the defect point and the injected current was proposed.