Conductivity and microstructure of inkjet printed nanoparticle silver layers processed with intense pulsed light (IPL) sintering on various polymeric substrates

Abstract

Novel manufacturing methods for flexible, light weight and cost-efficient electronics have gained high interests in the recent years, especially the additive printing technologies are of major relevance. Here, the digital inkjet printing technology is an attractive printing method due to its additive, high precision and upscalable deposition process. One of the key components of a printed electronic device, such as capacitor, transistor and sensor, is the conducting track. A major requirement is the device dependent electrical performance induced by an appropriate post treatment process. Traditional thermal sintering via an oven or hotplate requires on one hand long sintering times (up to minutes and hours) and on the other hand high sintering temperatures (above 150 °C - 300 °C), which are unsuitable for flexible polymeric foils with low glass transition or melting temperature. However, the novel method of intense pulsed light (IPL) sintering has great potential when it comes to the fabrication of functional layers on thin, flexible and temperature instable polymeric foils. In our research, the IPL sintering methodology is used to convert printed liquid films into solid and conducting metallic layers on various flexible polymeric substrates, like Polyethylene terephthalate (PET), Polyethylene naphthalate (PEN) and Polyimide (PI). Based on their glass transition temperature as well as applied energy densities the defect formation in the micrometer rang was analyzed. Furthermore, the electrical performance was measured and the conductivity calculated. It was found, that the substrate material property in terms of glass transition temperature and melting point have a prominent influence on the defect rate and the electrical performance.