Fabrication Of Flexible Metal Mesh By Crack Templates And Their Applications In Electric Heaters

With the boom of organic electronic devices,more and more attention has been paid to the flexible electrodes.However,the mechanical flexibility of traditional ITO is poor,which makes it hardly meet the demands of the market.Therefore,looking for alternative materials has become a frontier topic in the field of transparent conductive film.The metal mesh which is known for its high conductivity and flexibility stands out from numerous alternative materials.In this work,metal mesh films with different structures were fabricated by vacuum evaporate plating and electroplating metal wire on the substrate by using spontaneously cracked organic compounds as the mask templates.And the properties of metal mesh films were studied.The main research results include:1.The crack templates with different surface topography were prepared by spin coating and knife coating.The factors affecting of surface morphology of the crack templates were studied.It is shown that with the decreasing of film thickness,crack width and crack spacing become smaller gradually,and the homogeneity of surface morphology is getting better and better.With the increasing of drying temperature,crack width and crack spacing become larger.Therefore,the surface morphology of crack templates can be controlled by adjusting film thickness and drying temperature.2.The random Ag mesh films were fabricated by using crack template method combined with vapor deposition process.Their photoelectric properties were analyzed by the four-probe and the transmission absorption spectroscopy.It is shown that the Ag mesh films have excellent photoelectric properties.And the wall-like Ag mesh structures can be easily made to improve conductivity by increasing the thickness of the metal wire without compromising much in transmittance,so as to obtain the films with excellent photoelectric properties,whose quality factor can up to 1607.In addition,we have prepared a double mesh structure which is composed of a big Ag mesh with broad and sparse metal wire and a small Ag mesh with narrow and dense metal wire.The narrow and dense metal wire of the small Ag mesh can fill the large gap of the big Ag mesh.The double mesh structure has two advantages over single grid:(1)the haze is increased;(2)the electrical conductivity is enhanced.Therefore,Compound double mesh structure is expected to become the ideal window of solar cell electrode.3.ITO / Au mesh(ITO / AuM)composite films and ITO / Cu mesh(ITO / CuM)composite films were fabricated by using crack template method combined with electroplating process respectively.It is shown that the photoelectric properties of compositefilms are far better than the original ITO film: the Figure of Merits(FoMs)of ITO/AuM composite films is increased almost 3-times.the FoMs of ITO/CuM composite films is increased about 25-times.A PET / ITO substrate which has low transparence in UV and IR was used as the substrate of ITO/CuM composite films.The ITO / CuM composite films not only have the excellent flexibility and conductivity of Cu mesh,but also obtain low transmittance in UV and IR of ITO which lead to outstanding sunshade ability.So ITO/CuM composite films have a potential application values in the flexible optoelectronic devices and reducing building energy consumption.4.The electric heating performance and stability of the metal mesh film were tested:(1)It is found that the ITO/AuM composite films has better electrical efficiency than ITO films,with a 8V DC bias voltages the electrical heating rate of the ITO/AuM composite films is almost 6-times of that of the ITO film and the maximum heating temperature is also much higher than ITO.(2)Coated Au on the Ag mesh surface bring about an excellent antioxidant activity of the Ag mesh films.(3)Compared with the difference of flexibility between indium oxide doped tin/metal mesh(ITO/MM)composite films prepared by vapor deposition and electroplating method.It is shown that the flexibility of ITO/MM composite films prepared by electroplating is better than that obtained by vapor deposition method;the sheet resistance of ITO/MM composite films did not significantly increase after 1000 times of bending,showing that the brittleness of ITO film is overcome effectively.