The Study On The Scalable Synthesis Of Flower-like Silver Powders And Their Application In Flexible Printed Electronic

As a major trend in the development of electronic devices in the future,micro-flexible devices require further innovations in printed electronic technology.Therefore,the development and research of printing technique and printed materials are critical for obtaining ultrathin flexible devices.Current research shows that the three dimensional（3-D）silver particle has remarkable low-temperature sintering behavior which result from its unique three-dimensional nanostructure.3-D Ag particle-based laser-etched paste have been drawing more attentions in broad research fields due to its low-cost,high adhesion,high pattern resolution,high weather resistance,long life and compatibility with flexible substrate.Based on above discussion,we introduce a facile and controllable synthetic method of monodispersed submicron flower-like silver particles（Ag SMFs）which is about 400nm¹.1μm in size.More importantly,the maximum amount of Ag SMFs synthesized in one batch was about 1000 g in this study.What’s more,using some advanced morphological characterization methods（SEM,TEM,XRD,UV-vis,etc）to optimize synthesis process of Ag SMFs,explore silver growth mechanism and low-temperature sintering and fusing mechanism.By tuning the reaction condition,a series of submicron silver particles with acute branches were obtained,and the feature size of each branch is about 10 nm.The citrate molecules preferentially bind to（111）plane of face-centered cubic（fcc）structure of silver.This promoted anisotropic growth maximizing the surface area of（111）plane of Ag SMFs.The sintering and fusing temperature of Ag SMFs were about 60°C and 200°C,respectively.Ag SMFs with surface modification（iodine treatment）paste has a lower percolation threshold,and the resistivity can still be maintained at 6.094×10^-3Ω·cm when the silver content was reduced to 25 wt%.In addition,Ag SMFs paste can be quickly sintered and cured by low-power laser due to its low-temperature sintering and curing behavior.To determine the comprehensive practical performance of silver paste,we conducted some industry standard test methods（85°C/85%RH reliability test,thermal shock test,bending test）,and test results show that Ag SMFs paste has a sufficient reliability under high temperature and high humidity condition and thermal shock resistance.Moreover,the resistance variation of Ag SMFs paste after bending test（small curvature diameter）was within an acceptable range.With above intriguing and excellent performance mentioned,Ag SMFs paste not only can meet the requirements of current practical device,but also is expected to be widely used in ultrathin flexible printed electronics.Based on the high-performance Ag SMFs paste and low-power laser ablation technology,the conductive circuit line width and distance was controlled to be 18μm and15μm,respectively.And Ag SMFs paste can be applied to the manufacturing process of touch panels for mass production.Based on high-performance Ag SMFs paste and low-power fast laser curing/sintering technology,a skin electronic model with good skin compatibility and a sensitive touch capacitor were manufactured.In short,the All-laser process based on high-performance Ag SMFs paste has extensive application prospect in electronic components such as ultrafine circuits,ultrathin touch screen,printed capacitors and flexible fingerprint locks.