Research On Low-cost Process Of III-V Multi-junction Solar Cells

Gallium arsenide(GaAs)-based ?-? multi-junction solar cells have been widely used in aerospace,satellite and other fields due to the high photoelectric conversion efficiency and high reliability.Compared with silicon solar cells,?-? solar cells are limited in civil applications due to their high cost.Therefore,it has been widely concerned by the industry on how to reduce the cost.The cost reduction of ?-? multi-junction solar cells mainly includes efficiency improvement and process improvement.With the continuous improvement of material quality and the continuous optimization of device structure design,the efficiency of ?-? multi-junction solar cells is also improving.It is very difficult to improve the efficiency of three-junction solar cells.It is an important way to reduce costs on exploring innovative preparation technology of solar cells.In this paper,the bonding and unbonding processes of flexible ?-? multi-junction solar cells and the electrode preparation processes of ?-? solar cells are systematically studied.The main research results are as follows:1.The bonding and unbonding processes of flexible ?-? multi-junction solar cells were studied.After comparing a variety of bonding and unbonding methods,the UV curing adhesive bonding and UV laser unbonding combined temporary bonding technology optimization program was selected and explored and optimized.Through the exploration and optimization of laser release material homogenization,curing parameters,temporary bonding,adhesion of UV glue and unbonding on the temporary substrate,a temporary bonding process program suitable for the preparation of flexible ?-? multi-junction solar cells was realized.This program had strong wafer size compatibility,optimized the problem of difficult bonding,and greatly reduced the cost.2.The method of using ITO as the electrode of ?-? solar cell instead of traditional metal grid line electrode was studied.On the basis of in-depth analysis of the structure and optical properties of ITO thin films,the lattice structure and surface characteristics of ITO thin films,the relationship between the transmittance of ITO thin films and process parameters,and the relationship between the refractive index and reflectivity of ITO thin films and substrate materials and ITO thickness were explained.ITO thin film material had good conductivity,transmittance and process compatibility,which provided a very potential electrode material for low-cost preparation of solar cells.