Research On Interface Improvement And Efficiency Improvement Of Graphene/silicon Solar Cells

In recent years,graphene/silicon（Gr/Si）solar cells are expected to realize the production of low-cost and high-efficiency photovoltaic devices due to their room temperature preparation process and high compatibility,which has attracted widespread attention from domestic and foreign researchers.However,the improvement of the efficiency of Gr/Si solar cells is still the main problem that needs to be solved urgently.By improving the light trapping of the silicon substrate and the regulation of the Gr/Si interface,promoting the generation of photogenerated carriers and reducing the interface recombination of carriers to achieve their performance.This paper studies the influence of the introduction of different light trapping structures and new two-dimensional interface layers（MoS₂,WS₂）on the performance of graphene/silicon solar cells.The main research contents are as follows:Using few-layer graphene（3～5）to replace single-layer graphene,Gr/Si devices were constructed after annealing at 400℃,which improved the work function and conductivity of graphene,optimized device performance,and improved photoelectric conversion efficiency from 0.78%Increased to 2.58%.Three kinds of micro-nano structures are introduced in the Gr-Si interface:silicon nanoholes（Si NHs）,silicon pyramids（Si Ps）and silicon nanowalls（Si NWs）structures to improve the light trapping ability of silicon wafers and greatly increase the short-circuit current of the device Density(J_SC),but the overall performance of the device is affected by the morphology.Only the efficiency of Gr/Si NWs solar cells has increased to 3.03%,and 4.38%after nitric acid doping.Electrochemical intercalation was used to exfoliate molybdenum disulfide（MoS₂）crystals to obtain nanosheets which were introduced into the Gr-Si interface as a hole transport layer.Increase the Schottky barrier height of the device to block electrons,accelerate the tunneling of holes,and avoid serious interface recombination.The open circuit voltage(V_OC)of the device Gr/MoS₂/Si has been greatly improved,the J_SC has also increased,and the photoelectric conversion efficiency can reach 6.97%,and after nitric acid doping,it can reach 7.95%.Using electrochemical intercalation to prepare tungsten disulfide（WS₂）nanosheets as a hole transport layer to optimize Gr/Si devices.After constructing the Gr/WS2/Si device,it is found that its J_SC is greatly improved,and its photoelectric conversion efficiency can reach 7.54%,and it can reach 9.82% after HNO₃ doping.