Simulation analysis of impact of silicon substrate selection on performance of heterojunction solar cells

Abstract

The simulation of the electrical and optical behaviour of solar cell has been established as an essential tool for both improvement of existing devices and development of new ones. In this study, the effects of excess minority lifetime and concentration of n-c-Si on heterojunction solar cell performance are discussed to attempt to understand the possible key technique of 24·7% heterojunction with intrinsic thin layer (HIT) solar cell presented by Panasonic Company. Two basic models, Shockley–Read–Hall (SRH) recombination and Auger recombination equations, which can describe the recombination behaviour of carriers in the bulk of monocrystalline silicon, are discussed. This study improves the understanding of this device and to derive arguments for design optimisation. The simulated results show that the heterojunction solar cell has open circuit voltage of 0·75 V, short circuit current of 38·9 mA cm−2, fill factor of 0·836 and efficiency of 24·4% under the effective lifetime of 1×10−3 s, and substrate doping concentration of 1×1016 cm−3. These results of simulation can coincide with Panasonic’s latest 24·7% HIT solar cell.