Highly Responsive PEG/Gold Nanoparticle Thin-Film Humidity Sensor via Inkjet Printing Technology
Journal
Langmuir
Journal Volume
35
Journal Issue
9
Pages
3256-3264
Date Issued
2019
Author(s)
Su, C.-H.
Chiu, H.-L.
Chen, Y.-C.
Yesilmen, M.
Schulz, F.
Ketelsen, B.
Vossmeyer, T.
Liao, Y.-C.
Abstract
In this study, a highly responsive humidity sensor is developed by printing gold nanoparticles (GNPs) grafted with a hygroscopic polymer. These GNPs are inkjet-printed to form a uniform thin film over an interdigitated electrode with a controllable thickness by adjusting the printing parameters. The resistance of the printed GNP thin film decreases significantly upon exposure to water vapor and exhibits a semi-log relationship with relative humidity (RH). The sensor can detect RH variations from 1.8 to 95% with large resistance changes up to 4 orders of magnitude with no hysteresis and small temperature dependence. In addition, with a small thickness, the sensor can reach absorption equilibrium quickly with response and recovery times of ≤1.2 and ≤3 s, respectively. The fast response to humidity changes also allows the GNP thin-film sensor to distinguish signals from intermittent humidification/dehumidification cycles with a frequency up to 2.5 Hz. The printed sensors on flexible substrates show little sensitivity to bending deformation and can be embedded in a mask for human respiratory detection. In summary, this study demonstrates the feasibility of applying printing technology for the fabrication of thin-film humidity sensors, and the methodology developed can be further applied to fabricate many other types of nanoparticle-based sensor devices.
SDGs
Type
journal article