Structural Design And Optimization Of Thin Film Solar Cells Based On Grating Structure

The only purpose of the study of solar photovoltaic power generation is to improve conversion efficiency and reduce the cost, make the true green energy used in our lives. The solar cell conversion efficiency is one of the main factors of restricting current popularization application of solar battery. The present main research to improve the efficiency of solar cells are the following: One is in study of the material of the thin-film solar cell to improve the photoelectric conversion efficiency. The two is the research on the solar cell structure, such as the structure design of the window layer、the absorbing layer and the back layer,to improve the photoelectric conversion efficiency.In this paper, the research focuses on the second points, to optimize the design of the structure:1:A thin film solar cell with a grating in the lay er was designed to increase the absorption of gallium arsenide thin-film layer. By using rigorous coupled wave method, the absorption efficiency in the range of 280~900nm was analyzed for Ga As layer with single、double rectangular gratings and single cycle double filling ratio grating. When the thickness of absorption layer obtained under certain circumstances, in the TE and TM polarized light, the rate of the rectangular grating structure’s absorption compared to the non patterned absorber layer has been greatly improved. By analysing of the rectangular grating structure, the double rectangular grating and double ratio grating were designed. The absorption rate of double structure and double ratio grating than single rectangular grating with optimal structure increased in TE mode. These results indicate that, by designing the structure, random reflection photonic in grating increases the effect of time and distance in the light absorption layer, enhanced the absorption rate and finally improve the photoelectric conversion efficiency of the thin film solar cell.2: The grating structure has the characteristics of band gap, so we applied it to the back layer to the bottom of the photon transmission reflection can enhance the absorption rate indirectly. Through the simulation, it indicate that the back layer can improve the absorption rate.