The Preparation And Property Of High Performance CuS/g-C₃N₄ Composite Counter Electrode For QDSC

The quantum dot sensitized solar cell?QDSC?has merits of low price,ease of fabrication,environmental friendliness,and high theoretical efficiency and so on.It has great developing prospect.A QDSC consists of three working parts,photoanode sensitized by quantum dots,electrolyte and counter electrodes?CE?.The counter electrode in QDSC performs the function of extracting electrons from external then transferring them to electrolyte and catalyzing the reduction of electrolyte,which guarantees the continuous operation of QDSC.Such processes demand that the material used as counter electrode has high electron transport ability and good catalytic activity.Commonly,precious metal Pt is used as counter electrode?CE?material.However,its high price,as well as reaction with electrolyte which hampers its catalytic activity,limiting its large-scale application.The Cu S is a p-type semiconductor,which has high electrical conductivity and superior catalytic activity in electrolyte.Hence,its can be considered as an appropriate alternative of Pt counter electrode,which can improve efficiency of cells.The QDSC assembled with Cu S CE prepared via solvothermal method shows a power conversion efficiency of 1.54%.The QDSC assembled with Cu S CE prepared via in-suit method presents a power conversion efficiency of 1.96%.These are high that of Pt?1.25%?.The g-C₃N₄ possesses a layer structure similar to graphene and great chemical properties.It has large specific surface area.A successive ionic layer adsorption and reaction?SILAR?method is applied to load Cu S nanoparticels on surface of g-C₃N₄nanosheets synthesized via heating melamine.The deposited Cu S nanoparticles appeared serious aggregation on the surfaces of g-C₃N₄nanosheets.When the deposition cycle times of Cu S was 5 times,the CN-5Cu S CE possesses the best electrical conductivity.The urea is heated to obtain g-C₃N₄ powder and then a chemical bath deposition method is utilized to acquire Cu S/g-C₃N₄composite CE.The deposited Cu S nanoparticles prepared via above method even form flower-like clusters.The CN/30Cu S CE shows the best properties within all samples.Compared to Pt CE,the CEs prepared via above mentioned two methods get distinct improvement in conductivity and catalytic activity,and PCE presents significant increase.