Study On The Performance Of Quantum Dots Sensitized Solar Cell Based On The Binary And Ternary Composite Counter Electrode

The energy crisis and environmental problems caused by consumption of fossil energy,which is gradually aroused people’s attention.Solar energy is considered to be renewable,safe,clean and abundant energy in the future.As a very promising third-generation solar cell,the theoretical photoelectric conversion efficiency of quantum dot sensitized solar cells（QDSSCs）can reach 44%.As an important part of the counter electrode（CE）,the photoelectric performance would be greatly affected.For many years,the research of the composite counter electrode is relatively a few.The composite counter electrode is formed by the combination of two or more materials.The electrochemical performance of the composite counter electrode is higher than that of the single electrode.Generally,there are four methods to make the composite counter electrodes:doping,scraping,screen printing and spin-coating.Good electrical conductivity and catalytic performance give transition metal oxides and sulfides the opportunity to be designed as counter electrodes for QDSSCs.Silver nanoparticles（Ag Nps）have excellent electrical conductivity,their quantum size effect and small size effect make them have excellent catalytic activity,so they can be introduced into the counter electrode to improve the performance.Polyoxometalates（POMs）play an important role in electron capture and transmission and play a significant role in electron transport,and further improve battery efficiency.Carbon materials have the advantages of good conductivity,high stability,large specific surface area and good electrocatalytic performance.In addition,because their price is reasonable and can be prepared in large quantities.Therefore,this paper will try to synthesize C₃N₄ with high electrocatalytic activity and compound it with the counter electrode.In this paper,we synthesized binary and ternary semiconductor and their composite film electrodes,and carried out the photoelectric performance research.The main research contents are as follows:1.Co₃O₄ nanorods composed of nanoparticles were prepared by simple hydrothermal method and air calcination method,and flower-like Cu₂S were synthesized by hydrothermal method.Co₃O₄,PW₁₂/Co₃O₄,Cu₂S,Co₃O₄-Cu₂S,PW₁₂/Co₃O₄-Cu₂S counter electrode films were prepared by scratch-coating method and screen-printing method as well as applied them to QDSSCs.After passing the photoelectric performance test,the experimental results show that the PW₁₂/Co₃O₄-Cu₂S composite membrane has good electrocatalytic performance and can effectively capture and transfer electrons due to the introduction of POMs,and further improve the efficiency of the battery.The conversion efficiency of QDSSCs is 4.67%,which is higher than that of Cu₂S（46%）,PW₁₂/Co₃O₄（55.6%）and Co₃O₄（72%）CEs,respectively.2.CuInS₂（CIS）with nanosheet structure can be successfully prepared by solvent method.A series of Ag Nps composite counter electrodes films with different concentrations were prepared by CBD method,that is CIS,CIS/Ag-1,CIS/Ag-5,CIS/Ag-10.Compared with the single CIS electrode,the photo-electrocatalytic activity of CIS/Ag composite film on the electrode was significantly enhanced with the increase of Ag Nps loading and the conversion efficiency of CIS/Ag-10 was increased from CIS（1.60%）to CIS/Ag-10（2.67%）.What’s more,we propose the corresponding photoelectric mechanism.3.NiCo₂O₄ and NiCo₂S₄ were prepared by hydrothermal method.C₃N₄has large specific surface area,good conductivity and high stability,so this study tried to mix uniformly NiCo₂O₄and terpineol at the mass ratio of 1:2,and then a small amount of C₃N₄ was doped into the mixture and ground into paste.NiCo₂O₄/C₃N₄ composite membrane electrode was prepared by scraping method,NiCo₂S₄/C₃N₄composite film electrodes can be prepared in the same way.The results showed that the photoelectric conversion efficiency（PCE）composed of NiCo₂S₄/C₃N₄film electrodes can reach 4.26%.In addition,the photoelectric performance test can be confirmed the above results.