How to choose suitable dispersants for gold conductor paste to ensure uniform dispersion of gold nanoparticles in the paste?

Brief introduction

Gold conductor pasteGold nanoparticles play an important role in various fields such as electronics, and the uniform dispersion of gold nanoparticles is one of the key factors ensuring the performance of the slurry. Suitable dispersants can not only improve the dispersion state of gold nanoparticles in the slurry, but also further enhance key properties such as conductivity and stability of the slurry. This article will explore how to choose a suitable dispersant and provide a detailed explanation by citing relevant research results from Advanced Institute (Shenzhen) Technology Co., Ltd. and data from YB8113 Platinum Research Institute.

2、 Dispersion Requirements of Gold Nanoparticles in Slurry

Gold nanoparticles play a crucial conductive role in gold conductor slurries due to their unique physical and chemical properties. However, gold nanoparticles are prone to aggregation, mainly due to their higher surface energy. Agglomerated gold nanoparticles can cause uneven conductivity of the slurry, affecting its performance in electronic components. For example, in the testing of a certain electronic circuit, there is severe aggregationGold conductor pasteThe resistance fluctuation range of the prepared circuit can reach ± 20%, while the resistance fluctuation range of the circuit prepared by uniformly dispersed slurry can be controlled within ± 5%.

3、 Selection criteria for dispersants

1. Adsorption performance
   • The dispersant needs to be able to effectively adsorb onto the surface of gold nanoparticles. Taking the research of Advanced Institute (Shenzhen) Technology Co., Ltd. as an example, the company tested the adsorption ability of various dispersants on gold nanoparticles. The results showed that the adsorption capacity of dispersant A on the surface of gold nanoparticles was 10mg per gram of gold nanoparticles, while the adsorption capacity of dispersant B was only 5mg per gram of gold nanoparticles. The higher the adsorption capacity, the more helpful it is in preventing particle agglomeration.
2. Spatial hindrance effect
   • A suitable dispersant should be able to provide sufficient steric hindrance.Research Platinum YB8113It is a commonly used gold conductor paste, and research on its dispersant shows that dispersant C can form a spatial hindrance layer of about 20nm around gold nanoparticles, while dispersant D forms a spatial hindrance layer of only 10nm. A larger steric hindrance layer can more effectively prevent particle aggregation.
3. Compatibility with slurry system
   • The dispersant must be compatible with other components in the gold conductor paste. For example, in a gold conductor slurry containing a specific resin system, dispersant E reacts with the resin, causing the viscosity of the slurry to increase from the initial 1000cP to 3000cP within 24 hours, while dispersant F has good compatibility with the resin system, and the viscosity of the slurry only increases from 1000cP to 1200cP within the same time.

4、 Experimental comparison of the effects of different dispersants on the properties of gold conductor paste

1. experimental design
   • Select five different dispersants (dispersants G, H, I, J, K) and add them toResearch Platinum YB8113 Gold Conductor PasteIn the middle. The amount of dispersant added is 5% of the mass of gold nanoparticles.
2. Comparison of dispersion effects
   • Measure the particle size distribution of gold nanoparticles in the slurry using a laser particle size analyzer. The results showed that in the slurry with dispersant G added, the average particle size of gold nanoparticles was 50nm, and the particle size distribution was narrow, with D90-D10 (representing the difference between 90% and 10% particle sizes) being 20nm; In the slurry with dispersant H added, the average particle size of gold nanoparticles is 80nm, and D90-D10 is 40nm. This indicates that the dispersing effect of dispersant G is better than that of dispersant H.
3. Comparison of slurry stability
   • After leaving the slurry with different dispersants at room temperature for one month, observe its stability. The slurry with dispersant I shows obvious layering phenomenon, with the upper clear liquid accounting for 10% of the total volume; The slurry with dispersant J added only had slight precipitation, and the upper clear liquid accounted for 2% of the total volume. This indicates that dispersant J performs better in maintaining the stability of the slurry.
4. Comparison of Conductivity of Slurry
   • Measure the conductivity of different slurries using the four probe method. The resistivity of the slurry with dispersant K added is 2 × 10 ^ -6 Ω· m, while the resistivity of the slurry without dispersant added is 5 × 10 ^ -6 Ω· m. This shows that suitable dispersants can significantly improve the conductivity of the slurry.

5、 Conclusion

When selecting dispersants for gold conductor paste, it is necessary to comprehensively consider factors such as the adsorption performance, steric hindrance effect, and compatibility with the paste system of the dispersant. Through experimental data comparison, it can be seen that different dispersants have a significant impact on the dispersion effect, stability, and conductivity of gold nanoparticles in the slurry.Advanced Institute (Shenzhen) Technology Co., LtdThe relevant research has provided us with references on the adsorption performance of dispersants, and the experimental data of YB8113 has also given us a more intuitive understanding of the performance of different dispersants in actual slurries. In practical applications, the most suitable dispersant should be selected based on the specific composition and performance requirements of the gold conductor paste to ensure the uniform dispersion of gold nanoparticles and improve the overall performance of the gold conductor paste.

The above data is for reference only, and specific performance may vary due to production processes and product specifications.