Study On The Preparation Of Graphene Oxide And ZnO And Its Application In Solar Cells

With the continuous development and progress of the times,Graphene and its solar cells have gradually entered people's vision.Among them,Dye-sensitized Solar Cells?DSSCs?and Perovskite Solar Cells?PSCs?have rich raw materials,simple and safe preparation steps,and excellent photoelectric conversion capabilities.There was a wave of research.At present,there is still much room for improvement in the photoelectric conversion efficiency of DSSCs and PSCs,and the preparation of batteries is one of the main factors that directly determine the performance of DSSCs and PSCs batteries,so graphene and its derivatives can be used in DSSCs and PSCs batteries During preparation,this can improve its battery performance to a certain extent.Based on the above analysis,this thesis adopts Graphene Oxide?GO?and Zn O semiconductor materials prepared by the improved Hummers method as the raw materials for the preparation of the photoanode part of solar cells,and modify the photoanode part of DSSCs and PSCs through different experimental schemes.And improvement,to achieve the purpose of improving the photoelectric performance of the battery,and respectively adopt XRD,SEM,TEM,BET,AFM,and various battery photoelectric performance test systems and other detection methods for research and analysis.The main research contents and results are as follows:?1?The GO was prepared by the modified Hummers method that changed the order of oxidation temperature,and the phase composition,micro-morphology and crystal structure of the oxidation products were studied.The oxidation products are then used for thermal reduction and chemical reduction,the phase composition of the reduction products is studied and the different analysis is performed.The results show that the modified Hummers method with high temperature-low temperature-medium temperature as the oxidation temperature sequence has prepared GO thin layer structure with good micro-morphology.The GO has a polycrystalline structure with more functional groups attached to the edges and between the layers.The interlayer spacing is about 0.81 nm.Besides,t he thermal reduction GO is used to prepare RGO,and the heat treatment at 500? is the best.The chemical reduction is used to prepare RGO.The GO: hydrazine hydrate mass ratio =10:7 is the best.Comparing the characteristic diffraction peaks of the XRD of the prepared product,it is known that the reduction effect of the chemical reduction method is superior to the thermal reduction method.?2?Using Zn?NO₃?₂·6H₂O as the zinc source and C₁₂H₂₂O₁₁ as the fuel,the Zn O ultrafine powder was prepared by the solution combustion method,and the phase composition and micro-morphology of the product were studied.And using its products as raw materials to prepare DSSCs photoanode porous layer,using Zn O sol to prepare photoanode dense layer,study the influence of battery photoanode dense layer,porous layer film thickness,and heat treatment temperature on the DSSCs photoelectric conversion performance.The results show that: the solution combustion method successfully prepared Zn O ultrafine powder,which has a good microscopic morphology and the average particle size of the powder is about 50 nm,the specific surface area is 24.83cm²/g.According to the comprehensive experimental results,when the heat treatment temperature of the Zn O photoanode is 450°C,the dense layer film thickness is 210 nm,and the porous layer film thickness is 31?m,the DSSCs photoelectric conversion efficiency is significantly improved.The battery performance parameters of V_oc,J_sc,and FF are 0.63 V,12.73 m A/cm² and 64.70%,respectively,and its PCE can reach 5.20%,showing the better photoelectric conversion ability of DSSCs,which shows that the blocking barrier of dense layer and Zn O ultrafine powder The high specific surface area of the body can effectively improve the battery efficiency.When the heat treatment temperature of the Zn O photoanode is 450?,with the addition of the dense layer and the increase of the thickness of the porous layer,the photoelectric conversion efficiency of DSSCs is significantly improved.?3?Based on the above research,the chemical reduction method was used to synthesize RGO/Zn O powder,and RGO/Zn O powder was used to prepare RGO/Zn O photoanode.The phase composition and micro-morphology of RGO/Zn O powder products with different mass fraction ratios were studied The photoelectric conversion performance of DSSCs assembled with RGO/Zn O photoanode.The results show that the RGO/Zn O powder is mainly composed of Zn O.RGO doped with sheet structure modifies Zn O.The particle size of Zn O is about 50 nm and the size of RGO is about 100nm-200 nm.the microstructure of RGO/Zn O photoanode is good,and its surface roughness is 21.6nm.When the mass ratio of GO to hydrazine hydrate is 10:7 and the amount of RGO added is 1.25 wt.%,RGO/Zn O composite powder is used as the DSSCs photoanode,which has a relatively good photoelectric performance.The battery performance parameters of V_oc,J_sc,and FF are 0.66 V,13.11 m A/cm²,and 72.71%,respectively,and PCE can reach 6.27%.Comparing DSSCs prepared with Zn O as a photoanode,the PCE efficiency is increased by about 22%,which shows that the incorporation of RGO can modify Zn O to a certain extent and improve the performance of DSSCs batteries.indicating that the addition of RGO can improve the DSSCs electron transmission ability to a certain extent.Also,the Zn O/RGO electron transport layer was prepared by spin-coating process and heat treatment to study its influence on the photoelectric properties of PSCs.The results show that the Zn O/RGO electron transport layer has a good micro-topography,and its surface roughness?Ra=15.2nm?is better than that of the Zn O electron transport layer?Ra=17.1nm?.The PCE of PSCs with Zn O/RGO as the electron transport layer can reach 12.03%,and the battery performance parameters of V_oc,J_sc and FF are 1.07 V,17.91 m A/cm² and 62.98%,respectively,comparing the photoelectric conversion of PSCs prepared with Zn O as the electron transport layer The efficiency?PCE=5.29%?has increased by 127%,which shows that the addition of RGO film can effectively prevent the chemical reaction between Zn O and perovskite materials.