Fabrication And Properties Of AgNWs-based Transparent Conductive Films On 3D Substrates

At present,transparent conductive films(TCFs)play an important role in some fields,such as touch panels,liquid crystal displays,solar cells,organic light emitting diodes.The main commercial materials of TCFs is indium tin oxide(ITO),due to its low electrical resistance and high transparency.However,the disadvantages,such as the rare metal of indium and the brittleness,limit the applications of ITO in flexible optoelectronic devices.Alternative materials to ITO,such as conducting polymers,carbon nanotubes,graphene,metal nanowires exhibit greatly improved flexibility.Wherein,silver nanowires(AgNWs)-based TCFs show excellent optical transmittance,electrical conduction and good flexibility.So,AgNWs are the most promising materials to replace ITO.To increase light utilization and improve performance,the surface of optoelectronic devices is developed 3D structured surface,such as solar cells of silicon nanowire arrays,silicon based solar cells with radial microcolumn arrays,In GaAs-based nanowire solar cells,core-shell array photodetectors.TCFs are a very important component in optoelectronic devices.To fully meet the requirements in new structural optoelectronic devices,it is necessary to study the novel TCFs on the substrates with 3D structured surface.In this paper,the study focused on preparation and properties of high performance AgNWs-based TCFs on various 3D substrates,including the treated 3D glass,poly ethylene terephthalate(PET)and polydimethylsiloxane(PDMS).1,The novel AgNWs/ZnO TCFs were prepared on the treated glass and PET substrates with 3D structured surface.The glass and PET substrates were scratched by glass cutter or doctor blade to get 3D structured surface.AgNWs network films were deposited on the treated 3D substrates,and then thin ZnO layer was employed to protect AgNWs from oxidation in air.The AgNWs/ZnO films showed the superior performances with the optical transmittance of ~88 %,and the sheet resistance of ~10?/sq.The films maintained the thermal stability of more than 1 month at 80 oC.In order to verify the adhesion of the TCFs,the AgNWs/ZnO films was pasted withscotch tape for more than ten times,the performances were almost unaffected.Flexibility testing of AgNWs/ZnO TCFs on the treated PET flexible substrate was carried out,it was found that there was little change in sheet resistance above 1000 times bending,which indicated that the films had a very good flexibility.Therefore,the high-performance AgNWs/ZnO TCFs on the 3D unconventional substrates were achieved,which can be comparable to conventional ITO films.2,Based on the above experiments,the stretchable AgNWs TCFs on the PDMS substrates with different 3D regular structured surfaces were fabricated by photolithography.The preparation procedure was as follows.SU8 photoresist was used.Different 3D structures were fabricated on Si substrate by photolithography including bars,columns,and square columns.AgNWs dispersion was spin-coated on the 3D structures to get AgNWs network films.The PDMS were drop-coated on 3D structures with AgNWs network films.After curing,3D AgNWs/PDMS stretchable TCFs were formed after peeling off.The results showed that AgNWs can be uniformly distributed in the surface of 3D PDMS structures with different sizes and morphologies,especially in the corners,the walls and the other special regions.The transmittance of the AgNWs/PDMS TCFs was 90 %,and the sheet resistance was 26?/?.The sheet resistance remained constant under various harsh conditions,including bending 1000 times at 5 mm curvature radius,bending at 1mm curvature radius,and30 % stretch.Under the 50 % stretch,the sheet resistance increased from 26 ?/? to38.5 ?/?.In the stretch fatigue test,the sheet resistance of the TCFs increased ? 12 %.The technique can provide a technical support for the applications of stretchable optoelectronic devices with 3D structured surface.