Two-Step Sintering Technique for Printed Electronics Applications

Sintering is one of the most critical post-processes in electronics printing. Most printed electronics are fabricated with metallic nanoparticles inks, which are not electrically conductive when freshly deposited because the metallic nanoparticles are typically coated with organic additives to prevent agglomeration.

The sintering process is therefore required to decompose these enveloping organic additives so that metallic nanoparticles can contact one another. General requirements for the sintering process include short sintering time, low temperature, good electrical conductivity of the sintered patterns, and minimal damages to both substrate and printed pattern.

This two-step sintering technology focuses on the selective sintering of metallic nanoparticles inks within a short time to minimize deterioration to the substrates during the process. The sintered patterns exhibit better electrical conductivity and surface morphologies as compared to the conventional thermally sintered patterns. This sintering technique is greatly beneficial to the field of on-demand 3D printing of electronics and the sintering of any metallic nanoparticle inks.

This technology comprises of the following:

• A two-step method, process sequence and parameters to quickly and effectively sinter any types of metallic nanoparticle inks
• The configuration or set-up can be re-developed with potential partners to be incorporated into their machines or existing processes

Potential applications for this technology, but not limited to, are as follows:

• Sintering of any metallic nanoparticles (MNP) inks, including those with organic encapsulation/coating
• Sintering of MNP inks on temperature sensitive substrates
• Sintering of MNP ink based conductive tracks that may be used in:
  • OLED & Flexible displays
  • Organic Photovoltaics (OPVs)
  • Electronics & Components – Flexible power storage, circuits
  • Integrated smart systems – sensor systems, smart textiles

According to market research, the overall printed electronics market experienced a growth of 8% from 2016 to 2017 and is set to increase by 10% in 2018. This brings the conductive inks and OLED display predominant market to about USD 35Bn in 2018.

• Shorter sintering time
• Selective sintering
• Minimal damages to substrates
• Increased electrical conductivity of the sintered patterns compared to conventional thermally sintered patterns
• Cost-effective and customizable
• Universal concept to sinter any metallic nanoparticles ink