Praperation And Performance Research Of Graphene/n-Si Schottky Junction Solar Cells

The new graphene/n-Si Schottky junction solar cells have attracted much attention because of their simple preparation process and low equipment requirements.However,due to the poor utilization of spectral efficiency and separation of photogenerated carriers in conventional batteries,the energy conversion efficiency of this type of battery is limited.Therefore,it is of great significance to optimize the device structure and improve the performance of graphene/n-Si Schottky junction solar cells.The purpose of this paper is to study the preparation of graphene/n-Si Schottky junction solar cells with high efficiency and low cost.By using a new cyclododecane transfer method of graphene,the introduction of silicon nanowire arrays SiNWs and silicon inverted pyramid arrays SilPa as a new type of battery antireflection substrate,passivation of silicon surface and preparation of graphene quantum dots GQDs as electron blocking layer and other means,graphene/n-Si Schottky junction solar cells with high efficiency and low cost were prepared.In this experiment,the morphology,structure and optical properties of SiNWs,SiIPa and GQDs were investigated by Scanning Electron Microscopy(SEM),X-ray Photoelectron Spectroscopy(XPS),Fourier Transform Infraed spectra(FTIR),Ultraviolet-Visible-Near Infrared Absorption spectra(UV-Vis-NIR),Photoluminescence spectra(PL)and Minority Lifetime testing system,etc.The different structures of graphene/Silicon Schottky junction photovoltaic cells were designed and fabricated.The photovoltaic performance of the device was investigated by a solar cell I-V test system.The main research contents and conclusions are summarized as follows:(1)The SiNWs were prepared by metal Ag assisted chemical etching method.The results show that SiNWs has excellent light trapping capability,the shorter the length,the lower reflectivity,but the higher the minority carrier lifetime,the better the performance of the prepared battery.When the length was 1 pm,the efficiency of Gr/SiNWs Schottky junction solar cell reached 2.16%.At the same time,passivation can effectively reduce carrier recombination rate,and passivated SiNWs can improve the performance of device to 2.54%.(2)The SiIPa were prepared by metal Cu assisted chemical etching.SilPa also has high light trapping capability,and the minority carrier lifetime is higher than SiNWs.For the first time,SiIPa was used as the substrate of the battery.Comparing the performance of Gr/SiNWs Schottky junction solar cells and Gr/SiIPa Schottky junction solar cells,the results showed that the energy conversion efficiency of Gr/SiIPa Schottky junction solar cell was 3.50%better than that 2.16%of Gr/SiNWs Schottky junction solar cell.Subsequent to nitric acid doped graphene electrodes,the HNO3/Gr/SiIPa Schottky junction solar cell efficiency was 5.63%.(3)GQDs were prepared by pyrolysis method.The research showed that the prepared GQDs have good dispersion,high crystallinity,and the band gap and luminescence properties have a strong dependence on the size,the size of GQDs can be effectively adjusted by the pyrolysis temperature.At the same time,Gr/GQDs/n-Si Schottky junction photovoltaic cells were prepared by introducing GQDs as an electron barrier layer at the interface between graphene and planar silicon.The results show that when the size of GQDs was 4-7 nm and the thickness of the electron layer was 26 nm,the Gr/GQDs/n-Si Schottky junction solar cell had the best performance.The performance of the device was improved to 11.69%by doping of graphene with nitric acid,annealing and spin coating TiO2 anti reflective coating.