| In the past ten years,people have paid more and more attention to the exploitation and utilization of green sustainable development energy,among which the utilization of solar radiation energy has attracted the attention of the world.The third-generation photovoltaic products,represented by perovskite solar cells(PSCs),have become highly efficient devices that convert solar energy into electrical energy.Since Kojima's first paper in 2009 reported PSCs with an energy conversion efficiency(PCE)of 3.81%PSCs have aroused great interest in exploration.The organic-inorganic hybrid perovskite materials have high carrier mobility,suitable band gaps,long carrier diffusion length,high absorption coefficient and long life Longer,so the development of PSCs is very rapid,the certified record-breaking PCE has reached 25.5%,while maintaining a low manufacturing cost.Transparent electrode(TE)is an indispensable and important part of many optoelectronic devices including solar cells.The most commonly used material for preparing transparent electrodes is indium tin oxide(ITO).ITO has a high transmittance(88%).It has a low sheet resistance(15?/sq).Although ITO has good photoelectric properties,indium is scarce.As the demand increases,the production cost continues to rise.At the same time,ITO film is brittle,which hinders its use in flexible products.Widely used,so finding alternative materials for ITO has become a major problem to be solved urgently.Metal nanowires are a strong candidate to replace ITO.Among them,silver nanowires are the most common,but their production costs are relatively high.The price of copper is much lower than that of silver and indium.Copper and gold and silver exist at the same time in subgroup I.Both have a face-centered cubic crystal structure,which is similar to gold and silver and has high conductivity and flexibility.Therefore,copper nanowires(Cu NWs)are powerful candidates for the preparation of transparent electrodes.In this paper,electrospun polyacrylonitrile nanofibers are used as sacrificial masks,and combined with wet chemical etching methods to prepare copper nanowire network transparent electrodes(Cu NWs TE).Electrospun fibers are general templates for drawing low permeability threshold conductive networks,The thickness of the polyacrylonitrile nanofiber template prepared by the electrospinning technology is adjustable,the distribution is uniform,and the aspect ratio is as high as 104.The Cu NWs prepared by this method also have an ultra-high aspect ratio,and there are no protruding nodes between the nanowires.,Has good connectivity,and the prepared Cu NWs TE has good conductivity and transmittance.The specific research work is as follows:(1)In this paper,the influence of preparation conditions such as the thickness of copper film,electrospinning time,electrospinning receiving orientation,DMF steam treatment time,and wet chemical etching time on the experiment were studied,and the surface low resistance tester,optical microscope and Ultraviolet-visible spectrophotometer was used to characterize the sheet resistance,nanowire morphology and visible light transmittance of Cu NWs TE.It was found that the copper film of 60 nm was evaporated,the electrospinning was 60 s,and the polyacrylonitrile nanofibers were cross-received.The Cu NWs prepared under the conditions of DMF steam treatment for 30 s and wet chemical etching for 6 min have a smooth and continuous surface,an aspect ratio of up to 104,and no bumps.The prepared Cu NWs TE has a transmittance of 80%at 550 nm,with an average The sheet resistance is 21.72?/sq,which is almost comparable to ITO electrodes.(2)Prepare inverted PSCs with Cu NWs TE with different coverage rates as the bottom electrode.The device structure is Cu NWs TE/Ni Ox/CH3NH3Pb I3/PC61BM/BCP/Ag.It is found that Cu NWs prepared when the wet chemical etching time is 6 min TE has a relatively high energy conversion efficiency in PSCs.At this time,the coverage rate of the nanowires is 32%,and the quality factor of the transparent electrode is 4.94×10-3(?/sq)-1.The experimental results show that transparent electrodes prepared by using Cu NWs have great application prospects in future optoelectronic devices.(3)Through the optimization of the electrospinning time and wet chemical etching time,it is found that the copper film of 60 nm is evaporated,the electrospinning is 100 s,the polyacrylonitrile nanofiber is cross-received,the DMF steam treatment is 30 s,and the wet chemical etching is The flexible Cu NWs TE prepared under the condition of 25 min has good flexibility,the transmittance at 550 nm is 68%,and the average sheet resistance is 13.05?/sq.Experiments show that Cu NWs is a strong competitive material for the preparation of flexible transparent electrodes. |
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