Experimental Research On Thermal Conductivity Of Ag Nanowire Transparent Films

In recent years,Ag nanowires(Ag NWs)have attracted great attention,showing unique electrical and thermal properties in physics,chemistry,biology and other fields.These include enhanced Raman reflection,catalysis,data storage,biological and medical sensors,and strong spectral antibacterial activity,which is non-toxic to human cells.With the development of thin and light electronic devices,the research and design of thin and layered structures in electronic devices become very important.Nano silver wire showed good characteristics in electrical conductivity,visible through sex and stability,It is widely used in the development and manufacture of flexible photoelectric applications such as flexible liquid crystal display,touch screen,thin film transistor,organic light emitting diode and solar cell.For the design and optimization of these applications,the thermoelectricity of nanowire arrays is very critical and fundamental,but the research on their thermal properties is very little.As a new multi-functional ITO substitute material,nanometer silver transparent film has a significant influence on thin electronic devices due to its heat dissipation effect.Conductive electrodes based on silver nanowires have shown potential in large area flexible photoelectric applications.Currently,efforts are being made to reduce the surface roughness of Ag NWs thin films to improve their photoelectric and thermoelectric properties.Although nanometer silver wire itself has excellent photoelectric performance,it is still a difficult problem to improve the thermoelectric performance of Ag NWs electrode when the transmittance is more than 90%.It is a very feasible method to change the nano silver wire mesh on the substrate surface.The spacing and density of the mesh and the overlap form can control the photoelectric and thermoelectric properties of the nano silver wire mesh.In the experiment,the sample was heated to change the contact strength between the grid of silver nanowires,so as to optimize the photoelectric and thermoelectric properties of silver nanowires thin films.In this paper,silver nanowires was uniformly coated on PEEK fiber substrates by dip coating method and heated at different temperature and different times.The thermal diffusivity of silver nanowire transparent films after different heat treatment temperatures and times was measured by transient electrothermal technique(TET).The variation trends of thermal conductivity,resistance temperature coefficient and Lorentz number were obtained.The experimental results show that the thermal conductivity of the transparent film increases with the increase of heat treatment temperature,and increases with the extension of heat treatment time under the condition of 20-120?.The lorentz number is on the rise,but it is not stable because of the grid structure.The resistance temperature coefficient increases with the increase of heat treatment temperature,and increases with the extension of heat treatment time,and the slope increases significantly after 1h.The mechanism of acoustic-electronic heat transport in transparent nano-silver wire films was analyzed from two perspectives of single nano-silver wire and nano-silver wire grid.The influence of structure scattering and interface scattering on the thermal conductivity of nanosilver wire transparent thin films is further analyzed by using the acoustic-electronic thermal conductivity calculation model considering interface scattering.The effect of heating treatment on the grid morphology of nano-silver wire transparent thin films is also analyzed.From the variation trend of conductivity,it can be seen that heating treatment can not completely destroy the net in nano-silver wire thin films when the heat treatment temperature is less than 120 ?.In lattice structure,energy is still transported along the grid,and only secondary crystallization occurs at the nodes,which enlarges the acoustic-electronic free path at the nodes and improves the thermoelectric properties of the films.Finally,the development trend and application prospect of nano silver wire in scientific research and material application are prospected.