Electrohydrodynamic printed nanoparticle-based resistive temperature sensor

Abstract

Temperature sensors based on the principle of a change of resistance are fabricated on polyethylene terephthalate (PET) substrates using a silver nanoparticles (AgNPs)-based ink using a bespoke drop-on-demand (DoD) electrohydrodynamic (EHD) printer. Two sensors consisting of either a single or double layer of silver were deposited using EHD printing and were found to exhibit an internal resistance of a few hundred ohms for the double-layer sensor compared to 1 kΩ for the single-layer sensor. The achieved pattern width was almost half the size of nozzle internal diameter (160 μm), and printed without treatment of substrate and nozzle. The sensors were characterized over a temperature range of 20°C to 110°C. Both sensors showed a linear behavior with low hysteresis within the temperature ranges considered in this study and are found to recover the nominal resistance value with good reproducibility. The double-layer sensor showed high sensitivity with a temperature coefficient of resistance (TCR) of 3.4×10-3 ℃−1, which is an order of magnitude larger than that observed for the single-layered sensor with a TCR of 8.41×10-4 ℃−1. The sensors were also tested in a controlled humid environment and results are presented on the dependence of the internal resistance on the level of humidity. The proposed flexible printed sensors are promising for temperature monitoring systems and wearable technologies.

Drop‐on‐Demand Electrohydrodynamic Printing of Nematic Liquid Crystals

“…In contrast to printing techniques where the material is pushed out of a nozzle (e.g., using a piezoelectric transducer), electrohydrodynamic (EHD) printing uses electric fields to extract liquid jets from a nozzle to deposit ultrasmall droplets onto a substrate, offering novel possibilities for fabricating micro/nanosized structures that overcomes the limits imposed by surface tension and viscosity when trying to deposit small droplets using inkjet printing. [33][34][35][36] Therefore, EHD printing presents the possibility of printing LC droplets with very small feature sizes that could lead to novel director profiles inside the LC droplets. In principle, this could be further exploited to manipulate certain LC ordering transitions for new LC dropletbased technologies.…”

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

“…In comparison, additive manufacturing (AM) technology has the advantage of directly depositing multi-layered structures and ultra-micro thin films. It also offers significant cost-effectiveness, the potential for large-scale production, and a reduced environmental impact [ 26 ]. In the past decade, considerable efforts have been dedicated to reducing the printing resolution from micrometers to nanometers, which is crucial for advancements in printed electronics technology [ 27 ].…”

“…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 ].…”

“…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 ]. The sensor’s sensitive area was around 3500 μm × 5000 μm, with a line width of 90 μm.…”