Nickel Based RTD Fabricated via Additive Screen Printing Process for Flexible Electronics

Abstract

A novel nickel (Ni)-based resistance temperature detector (RTD) was successfully developed for temperature monitoring applications. The RTD was fabricated by depositing Ni ink on a flexible polyimide substrate using the screen printing process. Thermogravimetric analysis was performed to study the thermal behavior of the Ni ink, and it was observed that the Ni ink can withstand up to 200 • C before the decomposition of the binder in the ink system. Scanning electron microscopy and white light interferometry were used to analyze the surface morphology of the printed Ni. X-ray diffractometry was used to obtain structural information, phase, and crystallite size of the deposited Ni nanoparticles. Energy dispersive X-ray spectroscopy was used to obtain semi-quantitative information of the elements present in the fabricated RTD. The capability of the RTD to detect temperatures varying from −60 • C to 180 • C, in steps of 20 • C, was investigated at a constant relative humidity of 20%RH. The results of the RTD demonstrated a linear response with resistive changes as high as 113% at 180 • C when compared with its base resistance at −60 • C. An average TCR of 0.44%/ • C was calculated for the printed RTD with a response time of <10 s. The obtained results demonstrated the feasibility of employing Ni on flexible substrates for the development of flexible temperature sensors. INDEX TERMS Flexible temperature sensor, nickel, RTD, screen printing, TCR, TGA, XRD. PAUL D. FLEMING received the B.Sc. degree in physics from The Ohio State University, Columbus, OH, USA, in 1964, and the master's degree in physics and the Ph.D. degree in chemical physics

Wearable temperature sensor for human body temperature detection

“…This value indicates that the surface free energy of the substrate is higher than the surface tension of the prepared ink. Therefore, when evaluated in terms of printability, the prepared ink was compatible with the substrate [32].…”

Recent Progress in Manufacturing Techniques of Printed and Flexible Sensors: A Review

“…Various temperature, strain, and pressure sensors have also been realized using additive screen-printing process. Turkani et al reported nickel (Ni)-based resistance temperature detector (RTD) on polyimide substrate for detecting wide range of temperatures varying from −60 • C to 180 • C (Figure 2j) [101]. The flexible RTD exhibited a relative resistance change of 113% with a temperature coefficient resistance (TCR) of 0.44%/ • C and response time of <10 s. The thin RTD film was also very stable and repeatable across the wide temperature ranges.…”

One-step photonic curing of screen-printed conductive Ni flake electrodes for use in flexible electronics

“…The usage of Cu is limited since it is prone to oxidation at low temperatures 59 . Ni, on the other hand, has the highest sensitivity and TCR relative to the other metals 36 .…”

“…The rapid high heat generated during photonic curing is dissipated via thermal conduction at the interface of the substrate using the thermal mass of the substrate 22 . In the process, neck formation phenomena occur between metallic particles and cause grain growth of particles; then, pores are removed, and a dense continuous conductive layer is achieved [36][37][38][39] .…”

“…Therefore, the curing process requires optimization depending on the chemical composition of the particles along with their size, distribution, shape, and degree of agglomeration 62 . Altering the curing process by changing the temperature, time, or pressure (ambient vs. inert) can cause significant variation in the performance for the same material due to the change in grain boundaries and specific surface area of metal particles 36,63 . Moreover, when the active component of an ink differs from traditional powders, such as flake-shaped metal particles, it requires higher temperatures than spherical particles 61 .…”