The Preparation Of Ag And AgCu Nanoparticles By Laser Ablation In Liquid For Flexible Printed Electronic Applications

Flexible electronic technology has broad application prospects in the fields of information,energy,medical care,and national defense.Because the development of flexible electronics technology has rigorous requirements for its conductive materials:low-temperature sintering and higher conductivity.Compared with other conductive materials,Ag nanoparticles can greatly reduce the melting point of the material and maintain high conductivity due to its small size effect.For preparing Ag nanoparticles below 20 nm,the main method is chemical method,which faces the problems of serious environmental pollution in the production process and expensive precursors.The mass production technology of ultra-fine(<20nm)Ag nanoparticle with high-quality(high purity,high conductivity,uniform particle size)and low cost is the basis for realizing the industrialization of nano conductive pastes for flexible electronics.This paper mainly studies the preparation of high-quality ultra-fine Ag and AgCu nanoparticles by laser ablation in liquid,and explores the application of ultra-fine silver nanoparticles in flexible printed electronics.The main conclusions of this research work are as follows:(1)Ultrafine Ag nanoparticles are prepared by laser ablation in liquid.This paper systematically studies the effects of laser flux,laser repetition rate,liquid layer thickness and other parameters on the yield and morphology of Ag nanoparticles.It is found that an increase in the laser flux,an increase in the repetition rate,and a decrease in the thickness of the liquid layer were all beneficial to the increase in the yield of Ag nanoparticles.This paper contrastively tests the effects of different solvents on the laser ablation of Ag materials.It is found that the micromolar Cl~-solution reduce the average particle size and size distribution of Ag nanoparticles with good stability.However,in the laser ablation in liquid process,the higher the concentration of surfactant(PVP),the smaller the Ag nanoparticles produce.Finally,through continuous laser fragmentation and high speed centrifugation,ultra-fine Ag nanoparticles with a particle size range of 3-9 nm are obtained by high-speed centrifugation.(2)A new type of ultra-fine AgCu nanoparticles is developed by laser ablation in liquid,which can achieve uniform mutual solubility with positive heat of missing.The effects of different solvents on the composition and morphology of AgCu nanoparticles are mainly studied.The effect of organic solvents is all very good.Most of the AgCu nanoparticles produced are below 20 nm,and the Ag and Cu elements inside the particles are evenly distributed.Among them,the most ideal liquid environment is ethanol solution,and the prepared AgCu nanoparticles have a particle size range of 1-6 nm,and the Ag and Cu elements in the particles are uniformly distributed.Furthermore,the higher the concentration of surfactant(PVP),the smaller the particle size and size distribution of the AgCu nanoparticles.In addition,a novel reactive laser ablation in liquid method was designed to ablate the Cu target in Ag~+solution to obtain AgCu nanoparticles with uniform element distribution.(3)Various applications of self-made ultrafine Ag nanoparticles in flexible printed electronic conductive pastes are developed.Three kinds of conductive inks are formulated for the electronic application of inkjet printing.Among them,the nano-Ag conductive ink dispersed in ethanol obtained an excellent performance of 2.94μΩ·cm(about 2 times that of bulk silver)under the low temperature sintering condition of 200°C,and the other two also obtained excellent performance.For printed electronic applications,commercial micron Ag paste was doped with Ag nanoparticles to improve its comprehensive performance.