Study On The Synthesis Of Conductive Silver Ink And IGZO Ink And The Preparation Of Their Thin Films

Printing electronics is an important technical innovation in the field of microelectronics. It can be used to manufacture electronic devices and associated products by printing process of various functional material inks. Among those functional inks, conductive silver ink has drew much attention due to the excellent propertis of printed silver thin films, e.g., good electrical conductivity and chemical stability. Based on the solubility of precursors, conductive silver ink can be divided into two types:particle-free type and particle-containing type. We synthesized and studied the particle-free silver ink in this paper, since this type of ink usually results in no precipitation, its film formation requires low heat treatment temperature below 200℃, and the synthesis process is compatibile with flexible substrates. Besides metallic materials, printable semiconductor materials are also the research focus of printing electronics. Therefore, the indium gallium zinc oxide (IGZO) material ink was also studied in this thesis. As a typical transparent metal oxide material, IGZO is a semiconductor material suitable for printing electronic devices, with fabulous electrical properties and low synthesis temperatures.First part of this paper presents the study on the synthesis, preparation, properties of silver citrate conductive ink and its film. Using silver nitrate as the silver source, sodium citrate as the reactant, silver citrate was prepared in the experiments; Using MEA,1,2-propanediamine as the complexing agent,2-Methoxyethanol, ethanol as the solvent, CMC as the binder, particle-free conductive silver ink was prepared with high stability, low viscosity and high silver content. The effect of several parameters-on the properties of the conductive silver thin film were studied, including complexing agent, organic solvent, binder and heat treatment temperature. The results show that compared to ethanol, using 2-Methoxyethanol as solvent resulted in better films with smaller surface roughness and smaller resistivity. Compared to 1,2-diamine, using MEA as complexing agent can have lower heat treatment temperature, and yielded dense films. Within our research scope, it was found that 250℃ is the optimum heat treatment temperature for the silver film. Finally, we prepared conductive silver wires by using ink-jet printing method. The silver wires exhibited good uniformity and surface roughness.Second part of this paper gives study on the synthesis, preparation, properties of IGZO ink and its film. With gallium chloride, indium chloride, zinc acetate dihydrate as theprecursors, MEA as the complexing agent,2-Methoxyethanol as the solvent, we prepared particle-free IGZO ink with high stability. Then the effects of Ga concentration on IGZO ink properties and the IGZO film properties were studied. It was found that the decomposition of IGZO ink precursors had two stages:the metal complexes firstly decomposed and hydrolyzed into hydroxides, and then the hydoxides experienced decarboxylation and became metal oxides. The XRD analysis revealed that the IGZO films annealed at 450℃ are amorphous. Besides, SEM characterization showed that the IGZO film had smooth surface and good uniformity. Finally the transmittance measurement showed that the IGZO films prepared in this study have a high transmittance (Up to 80%) in the visible range.