Study On The Light Trapping Enhancement Technology Of Crystalline Silicon Photovoltaic Devices Based On Silicon Nanowires Array

Silicon-based solar cells can directly convert solar energy into electric energy,which has the advantages of cleanliness,safety and efficiency.The introduction of trapping structure in silicon based solar cells can effectively improve the photoelectric conversion efficiency,and has gradually become a hot research topic.As a light trapping structure,silicon nanowires?Si NWs?have special nano-size effect,which can enhance the capture of sunlight and effectively improve the efficiency of solar cells.Silicon nanowires have shown great advantages in the application of silicon-based solar cells.In the nano-scale range,the change of morphology will have an impact on the efficiency of the solar cells.In this paper,different morphologies of Si NWs micro-nano arrays were fabricated by metal assisted chemical etching?MACE?,and the solar cells based on different morphologies of Si NWs were fabricated.The morphology control methods of Si NWs and the effect of energy of Si NWs on crystalline silicon solar cells with different morphologies were systematically studied.The research contents of this paper are follows:Firstly,the large scale Si NWs micro-nano arrays were fabricated by the MACE method.By changing the etching time of HF/H₂O₂ mixed solution,the length of Si NWs can be adjusted.Changing the pretreatment time of ultraviolet-ozone?UV/Ozone?and 5%hydrofluoric acid?HF?treatment,Si NWs micro-nano arrays with different filling ratios can be obtained.Secondly,crystalline silicon solar cells were prepared by n-type doping diffusion,surface passivation and screen printing electrodes.The performance of crystalline silicon solar cells with Si₃N₄ passivation layers and SiO₂ passivation layers were compared,which proved that crystalline silicon solar cells with Si₃N₄ passivation layers performed better.Finally,the effects of different length and filling ratios of Si NWs micro-nano arrays on photoelectric conversion efficiency were systematically studied.With the increase of the length of Si NWs,the reflectivity decreases gradually and the average reflectivity can be reduced to 1.49%when the length of Si NWs is 3000 nm.The photoelectric conversion efficiency of crystalline silicon cells gradually increases,and the efficiency reaches the highest at 3000 nm.The reflectivity of Si NWs increases first and then decreases with the increase of filling ratio of Si NWs.The photoelectric conversion efficiency of crystalline silicon cells based on different filling ratio of Si NWs increases first and then decreases.When the filling ratio of Si NWs is 49.71,the photoelectric conversion of solar cells is the highest.The anti-reflection effect of Si NWs micro-nano arrays is better than that of traditional pyramid arrays.The characteristic parameters of crystalline silicon cells based on Si NWs micro-nano arrays were higher than those based on traditional pyramid arrays.