Three dimensional simulated modelling of diffusion capacitance of polycrystalline bifacial silicon solar cell

Abstract

A three dimensional (3-D) simulated modelling was developed to analyse the excess minority carrier density in the base of a polycrystalline bifacial silicon solar cell. The concept of junction recombination velocity was ado-pted to quantify carrier flow through the junction, and to examine the solar cell diffusion capacitance for three illumination modes (front side, back side and both front and back sides). Plots of diffusion capacitance against grain size, grain boundary recombination velocity, junction recombination velocity and illumination wavelength were used to study the influence of cell parameters on the capacitance. The results indicated that junction and grain boundary recombination velocities played determinant roles, especially, for small grain size and long wav-elength. Hence, high diffusion capacitance was obtained for high junction recombination velocity, large grain size and long wavelength; while small grain size led to increased recombination centers and corresponding decrease in the diffusion capacitance