Fabrication of Low-Cost Resistance Temperature Detectors and Micro-Heaters by Electrohydrodynamic Printing

Abstract

EHD printing is an advanced deposition technology that is commonly utilized for the direct manufacture of electrical devices. In this study, meander-type resistive electrodes consisting of silver nanoparticles were printed directly on rigid glass and flexible polyethylene terephthalate (PET) substrates. High-resolution patterns of ≈50 µm linewidth were successfully printed on untreated surfaces utilizing a bigger nozzle of 100 µm inner diameter after improving the experimental settings. The manufactured electrodes were evaluated and used as Resistance Temperature Detectors (RTDs) and micro-heaters in a systematic manner. The temperature sensors performed well, with a Temperature Coefficient of Resistivity (TCRs) of 11.5 × 10−3/°C and 13.3 × 10−3/°C, for glass and PET substrates, respectively, throughout a wide temperature range of 100 °C and 90 °C. Furthermore, the RTDs had a quick response and recovery time, as well as minimal hysteresis. The electrodes’ measured sensitivities as micro-heaters were 3.3 °C/V for glass and 6.8 °C/V for PET substrates, respectively. The RTDs were utilized for signal conditioning in a Wheatstone bridge circuit with a self-heating temperature of less than 1 °C as a practical demonstration. The micro-heaters have a lot of potential in the field of soft wearable electronics for biomedical applications, while the extremely sensitive RTDs have a lot of potential in industrial situations for temperature monitoring.

An Aerosol Jet Printed Resistance Temperature Detector‐Micro Hotplate with Temperature Coefficient of Resistance Stabilized by Electrical Sintering

“…Table 1 shows a comparison of RTD-μHP devices fabricated using physical vapor deposition (PVD), [41] electrohydrodynamic (EHD) printing, [42] and AJP. [43] Compared to other fabrication method, AJP offers a higher resolution, therefore enables fitting a serpentine line with more turns into a small area. The longer and narrower line resulted in a higher resistance, which increased power density for RTD-μHP devices.…”

Electrohydrodynamic Printed Ultra-Micro AgNPs Thin Film Temperature Sensors Array for High-Resolution Sensing

“…Currently, there are limited reports on the fabrication of micro thin-film temperature sensor arrays using EHD technology. Even for individual thin-film temperature sensors, the sensitive area typically surpasses 10 mm 2 , with a minor portion falling within the range of 1 mm 2 to 2 mm 2 [ 26 , 36 , 37 ]. The line width of these sensors predominantly ranges between 50 μm and 100 μm [ 26 , 36 , 37 ].…”

“…Even for individual thin-film temperature sensors, the sensitive area typically surpasses 10 mm 2 , with a minor portion falling within the range of 1 mm 2 to 2 mm 2 [ 26 , 36 , 37 ]. The line width of these sensors predominantly ranges between 50 μm and 100 μm [ 26 , 36 , 37 ]. Waqas Kamal et al employed EHD technology to print nanosilver film temperature sensors on a flexible PET substrate [ 26 ].…”

“…Their study focused on the single-step heating characteristics of resistance, reporting a TCR of 768.7 ppm/°C and an upper limit of 105 °C for temperature measurement. Salman Ahmad et al applied EHD printing technology to fabricate nanosilver film temperature sensors on a rigid glass substrate [ 37 ]. The sensors possessed a sensitive area of about 5000 μm × 5000 μm and a line width of 50 μm.…”