Preparation And Properties Of Ag Nanoparticles Based Conductive Inks Mixed With Cu And Sn For Flexible Electronics

The printed electronics technology has many superior advantages over the traditional printed circuit board manufacturing technology,such as simpler process,less time,less manpower,cheaper equipment and lower cost.In addition,printed electronics technology can be regarded as a combination of printing technology and electronic manufacturing technology,and the process is essentially an additive manufacturing process.In this process,the material is deposited only at the desired location according to the design requirements,thus greatly reducing system waste and environmental pollution.As the key material in printed electronics,conductive inks affect the progress of the entire technology field.In the past decades,many researchers and engineers have dedicated to the study of conductive inks to promote the development of printed electronics technology.Some progress were made,but there are still some important issues that need to be resolved,such as the expensive cost of silver nanoparticle based ink and the high sintering temperatures of conductive inks.The main purpose of this thesis work is to seek a simple and effective method to reduce the sintering temperature and application costs of silver nanoparticle based ink,and develop a conductive ink with good performance.Short-chain molecular sodium citrate capped silver nanoparticles were used as conductive filler and deionized water was used as solvent,the effects of various functional additives and their content on the performance of conductive inks were studied.Finally,a water based silver ink capable of sintering at room temperature was successfully prepared.The ink can be sintered at room temperature,with the decreased sintering temperature the post-treatment process can be saved significantly,and its application cost is greatly reduced.In order to further reduce its application costs,tin nanoparticles and Cu-Sn mixed nanomaterials were also prepared to partially replace the expensive silver nanoparticles for the preparation of mixed conductive ink.Finally,mixed conductive inks were prepared,and their properties were further studied.Short-chain molecular sodium citrate capped silver nanoparticles and deionized water were used as the conductive fillers and the solvent respectively,an aqueous silver nanoparticle based conductive ink was prepared with appropriate amounts of various functional additives.The ink was printed on a glass substrate（non-porous substrate）,a conductive film with a resistivity of 1.73×10^-5Ω·cm was obtained after sintering at 150°C.When the silver ink was printed on a photo paper（porous substrate）,a conductive film with a resistivity of 3.96×10^-5Ω·cm can be formed at room temperature.The sintering process without high temperature can greatly reduce its application cost.In addition,the silver ink with good adhesion to the substrate and good cycle fatigue performance can be applied in printed electronics to manufacture flexible electronic products.In the study of mixed conductive inks,after the Ag/Sn mixed conductive ink was sintered at a low temperature of 130°C,the obtained conductive film had a resistivity of 6.5×10^-5Ω·cm.The resistivity of the conductive film was higher after sintering the Cu-Sn/Ag mixed conductive ink,because of the severe oxidation.