Characterization of crystalline silicon solar cells by electrical parameters

In order to analyze the possible defects effecting on efficiency of three types of industrial silicon solar cells: P-type of cast-multicrystalline silicon,Edge-defined Film-fed Growth(EFG) and single silicon solar cells,several important cell parameters,such as the curve of spectral response(External Quantum Efficiency,EQE),mapping of short-circuit current,ideality factors of diodes,saturation currents I0 and the parasitic resistances RS and RSH,were characterized and analyzed.After analyzing EQE curve with and without bias white light during EQE measurement,the mapping of defect induced shunt current in solar cells and electrical parameters of solar cells were respectively measured by Light Beam Induced Current(LBIC) and dark and illuminated current-voltage(I-V) measurements.Then,based on diode equivalent model of solar cell,the simulation of measured I-V curve was used to obtain some important parameters of solar cells.From these results,it shows that the main defects effecting on salar cell parameters are the grain boundaries,dislocation and impurity in bulk silicon for cast-multicrysalline silicon and EFG solar cells,but born-oxygen defect pairs for single silicon solar cell.Because of the variable type of minor carrier recombination centers in raw material,the final conversion efficiencies of cast-multicrystalline silicon,EFG and single silicon solar cells are 10.5%,11.7% and 15.7%,respectively.