Cu Nanoparticle Ink Dispersion Without Dispersants
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Solution Overview
Problem
Existing inkjet printing processes face challenges with dispersing Cu and CuO nanoparticles due to aggregation, clogging of nozzles, and substrate limitations, particularly requiring dispersants that increase energy demands and lead to volumetric shrinkage issues.
Innovation Solution
A process for preparing an ink with Cu and CuO nanoparticles that achieves dispersibility and stability without additives, by controlling oxygen states, using RF plasma treatment, vacuum drying, and quantifying ionic impurities, with specific conditions for zeta-potential, particle size, and interparticle distance, and using a polar solvent with low vapor pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If dispersants are used to disperse Cu and CuO nanoparticles, then dispersibility is improved, but energy consumption increases and volumetric shrinkage occurs
Solution Approach 1:
The invention extracts and removes dispersants from the ink composition entirely. By controlling the oxygen state of Cu and CuO nanoparticles (maintaining specific ratios of metallic Cu, Cu2O, and CuO), the particles achieve stable dispersion without requiring any dispersant additives, thereby eliminating the energy consumption and volumetric shrinkage issues associated with dispersant removal
Solution Approach 2:
The invention changes the chemical composition parameters of the nanoparticle mixture by precisely controlling the ratios of metallic Cu, Cu2O, and CuO. This parameter change in the oxygen state of the particles provides inherent dispersibility without needing external dispersants, resolving the contradiction between dispersibility and energy consumption
2Stability of the object's composition
If dispersants are used to disperse Cu and CuO nanoparticles, then dispersibility is improved, but volumetric shrinkage and cracking occur
Solution Approach 1:
The invention extracts and removes dispersants from the ink composition entirely. By controlling the oxygen state of Cu and CuO nanoparticles (maintaining specific ratios of metallic Cu, Cu2O, and CuO), the particles achieve stable dispersion without requiring any dispersant additives, thereby eliminating the volumetric shrinkage and cracking issues that occur when dispersants are removed after deposition
Solution Approach 2:
The nanoparticle mixture serves its own dispersion function through its controlled oxygen state composition. The specific ratio of metallic Cu, Cu2O, and CuO provides inherent steric and electrostatic repulsion that maintains particle separation without external dispersants, preventing the harmful volumetric shrinkage that would otherwise occur
3Reliability
If high heating temperature is used for conductorization, then conductivity is improved, but substrate damage occurs
Solution Approach 1:
The invention changes the chemical composition parameters of the nanoparticle mixture by precisely controlling the ratios of metallic Cu, Cu2O, and CuO. This parameter change enables effective conductorization at lower temperatures because the mixed oxidation states facilitate sintering and conductivity formation without requiring the high temperatures (200°C or higher) that would damage heat-sensitive substrates
Solution Approach 2:
The invention uses a composite nanoparticle material consisting of metallic Cu, Cu2O, and CuO in specific ratios. This composite structure provides both the reducibility needed for low-temperature conductorization and the final conductivity required for functional wiring, eliminating the need for high-temperature processing that would damage the substrate
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The ink exhibits excellent dispersibility and stability, allowing for precise wiring patterns without nozzle clogging and enabling use on substrates with low heat resistance, while reducing energy requirements and preventing volumetric shrinkage.
Implementation Method 1
using RF plasma treatment
Implementation Method 2
vacuum drying
Data Source
Figure 1~2
Figure 3~5
AI summary
Disclosed is a printing ink comprising Cu- and/or CuO-containing metal nanoparticles, which obtains excellent dispersion properties and successive dispersion stability without using additives such as dispersing agents. Specifically disclosed is a printing ink that comprises Cu- and/or CuO-containing metal nanoparticles and has no more than 2,600 ppm of ionic impurities in the total solid content. The printing ink is obtained by dispersing the Cu- and/or CuO-containing metal nanoparticles, which have no more than 2,600 ppm of ionic impurities in the total solid content, in a dispersion medium.