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2017
Conference Paper
Titel
Challenges of the intense pulsed light sintering of inkjet-printed conducting patterns on flexible substrates
Abstract
The development of novel manufacturing methods for flexible, light weight and cost-efficient electronics has gained high interests in the recent years. Due to its additive, high precision and digital process, the inkjet printing technology is an attractive fabrication process. The novel method of using intense pulsed light (IPL) to convert printed liquid films into solid and functionalized metallic layers has great potential when it comes to fabrication of electronics on thin, flexible and even stretchable polymeric foils. The focus of this research lies on the dependence of the defect rate and crack appearance on the glass transition temperature (Tg) during the IPL sintering process. Therefore, a nanoparticle (NP) silver ink was inkjet printed on various flexible polymeric foils with varying Tg. The silver layers were investigated optically as well as electrically and correlated to each other. Additionally, surface profiles revealed the formation of a defined crack of a few µm in depth and height around a printed silver layer at the silver-substrate border after the IPL sintering. It was found, that this crack can be directly correlated to the Tg of the used substrate. A lower Tg of the substrate resulted in a larger crack formation. In fact, conductivities were achieved up to 28% of the bulk silver conductivity without any large defects within the silver layer and the substrate, but even a crack in the micrometer scale and its impact on e.g. the reliability of a printed electronic device needs to be considered.
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