Method for forming conductive film at room temperature

Abstract

A method for forming a conductive film at room temperature is provided and includes steps of: adding AgNO3 into a first solution of dodecanoic acid; dropping n-butylamine and a diluted aqueous solution of a reducing agent into the first solution in turn, so as to initially obtain the dodecanoate-protected silver nanoparticles as a capping ligand; then using cyclohexane as a solvent to apply the silver nanoparticles onto a surface of a substrate to form a patterned film of silver nanoparticles; and finally immersing the substrate into a high concentrated aqueous solution of a reducing agent to chemically reduce the patterned film of silver nanoparticles into a conductive silver film. Thus, a patterned film or circuit can be conveniently and rapidly formed, and the silver nanoparticles can be applied to flexible substrates with low material cost and temperature sensitivity.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method for forming a conductive film at room temperature, and more particularly to a method using a reducing agent to chemically reduce a film of dodecanoate-protected silver nanoparticles pre-coated on the flexible substrate into a conductive silver film at room temperature.BACKGROUND OF THE INVENTION[0002]Low-cost liquid direct printing technology can be applied to a variety of patterned and deposition processes, such as processes of integrated circuits (IC), glass substrate circuits of large-size liquid crystal display (LCD), surface circuits of LED wafer, repair of IC open circuits, electronic tags or radio frequency identification (RFID), etc. Traditionally, plating and etching to form a conductive patterned circuit are generally done by lithography processes. However, due to the many complex steps required to construct a layer of circuit, it is relatively time-consuming and the manufacturing cost is higher. Therefo...

AI Technical Summary

Benefits of technology

[0006]A primary object of the present invention is to provide a method for forming a conductive film at room temperature, which includes steps of: firstly adding AgNO3 into a solution of dodecanoic acid; sequentially dropping n-butylamine as a silver-ion ligand and a diluted aqueous solution of a reducing agent to reduce silver ions into silver nanoparticles to initially obtain silver nanoparticles stably protected by dodecanoate as a capping ligand; then using cyclohexane as a long-term stabilizing solvent to spin-coat or print silver nanoparticles using dodecanoate as a capping ligand onto the surface of the substrate to form a patterned silver nanoparticle film; finally immersing the substrate into a high concentrated aqueous solution of a reducing agent to chemically reduce the patterned film of silver nanoparticles into a conductive silver film. This method can not only be used to conveniently and rapidly print the patterned film or circuit on the substrate, but also significantly increase the application potential of silver nanoparticles on the flexible substrate (i.e. PET substrate) which is non-heat-resistant and low cost.

[0007]A secondary object of the present invention is to provide a method for forming a conductive film at room temperature, which includes steps of: firstly using cyclohexane containing 0.5 wt % dodecanoic acid as a solvent to mix with silver nanoparticles using dodecanoate as a capping ligand into a long-term stabilizing preservation solvent (30-day preservation period) with 5.0 to 15.0 wt % silver nanoparticles, so that silver nanoparticles in the cyclohexane solution containing 0.5 wt % dodecanoic acid is unable to generate mutual aggregation and condensation, and the size uniformity of the nanoparticles can be kept. Therefore, it can improve the printing quality of silver nanoparticles applied to inkjet printing process.

Problems solved by technology

This method can not only be used to conveniently and rapidly print the patterned film or circuit on the substrate, but also significantly increase the application potential of silver nanoparticles on the flexible substrate (i.e. PET substrate) which is non-heat-resistant and low cost.

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