Synthesis and Fabrication of Graphite/WO3 Nanocomposite-Based Screen-Printed Flexible Humidity Sensor

Abstract

The resistive type of graphite/WO3 nanocomposite-based humidity sensor is fabricated through screen printing on a flexible polyethylene terephthalate substrate. Three different nanocomposite-based humidity sensors have been fabricated and analyzed for their humidity-sensing characteristics. The structure elucidation of the nanocomposite was carried out using x-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. By exposing the printed humidity sensor to relative humidity ranging from 11% to 97% at room temperature, its capabilities were studied. The relative resistance, sensitivity, dynamic response, and hysteresis were determined for all three devices, and they showed maximum responses towards relative humidity changes with the highest sensitivity of ≈ 60.8% and excellent hysteresis curves (maximum change of ≈ 1%). The screen-printed flexible humidity sensor exhibited less than a 5% change in the internal electrical resistance when subjected to various bending angles.

Improving Definition of Screen-Printed Functional Materials for Sensing Application

“…Measurements are an average of 10 fingers for each electrode. 20 100 100 silver 10 520−560 1500 silver 14 750 750 The nominal line width increased more significantly on the Melinex ST506 substrate than on Flextrace T24 due to the lower surface energy of the first one, resulting in prints with lower definition. Regarding the new functional inks based on rGO and NrGO, they required repetitive prints to achieve the printed layer continuity and thickness of the commercial ones since graphene forms agglomerates bigger than the opening rate of the mesh.…”

“…As one of the most used methods for printed electronics, screen printing stands out for its simplicity, scalability, effectivity, and robustness. , This leading technique allows the combination of multiple layers of different materials onto a flexible substrate by transferring the ink through a mesh with a blade/squeegee. By screen printing or by combining this method with other printing methods, different sensing devices can be fabricated, including environmental sensors (temperature, humidity, gas detection), biosensors (glucose, blood pressure), pressure sensors (touch sensors), and light sensors . Many of them are based on a simple structure which consists on a substrate, interdigitated electrodes, and the sensing film. , …”

Graphene-enhanced manganese dioxide functional ink infused with polyaniline for high-performance screen-printed micro supercapacitor

“…The printing was done on a flexible PET substrate with a polyester fabric screen with a mesh count of 120 threads per centimetre in both horizontal and vertical dimensions. The microsupercapacitor device was printed by creating the design onto the screen mesh [33]. The printing procedure embarked with the use of conductive silver ink as the first layer.…”

Direct-Ink Writing Processing of High-k Poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) and Its Integration into an All-Printed Capacitive Touch-Sensing Device

“…Furthermore, as the demand for facile integration, increasing complexity, and customized electronic devices rises, the need for efficient and precise manufacturing techniques grows. , Thus, additive manufacturing technologies, including inkjet printing, − gravure, , screen printing, − and direct-ink writing (DIW), , have been used to deposit various conductive and nonconductive functional patterns on rigid and flexible substrates. Screen printing is an additive manufacturing technique with superior material utilization, low process temperatures, the ability to handle large-scale production at low cost, and a printing process fast enough for mass production .…”