High-performance resistive humidity sensor based on Ag nanoparticles decorated with graphene quantum dots

Abstract

In this work, we present a low-cost, fast and simple fabrication of resistive-type humidity sensors based on the graphene quantum dots (GQDs) and silver nanoparticles (AgNPs) nanocomposites. The GQDs and AgNPs were synthesized by hydrothermal method and green reducing agent route, respectively. UV–Vis spectrophotometer, X-ray photoelectron spectroscopy and field-emission transmission electron microscopy were used to characterize quality, chemical bonding states and morphology of the nanocomposite materials and confirm the successful formation of core/shell-like AgNPs/GQDs structure. According to sensing humidity results, the ratio of GQDs/AgNPs 1 : 1 nanocomposite exhibits the best humidity response of 98.14% with exponential relation in the humidity range of 25–95% relative humidity at room temperature as well as faster response/recovery times than commercial one at the same condition. The sensing mechanism of the high-performance GQDs/AgNPs humidity sensor is proposed via Schottky junction formation and intrinsic synergistic effects of GQDs and AgNPs.

Recent Studies on the Humidity Sensor: A Mini Review

“…The humidity sensitive material, which serves as the core of the humidity sensor, has a sensitive signal to water molecules, influencing the conductivity. Hydrogen bonds, 14 intramolecular contacts, 15 electrostatic interactions, 16 hydrophilic and hydrophobic interactions, 17 chemical bonding, 18 etc. are some types of these interactions.…”

Bioanalytical Applications of Graphene Quantum Dots for Circulating Cell-Free Nucleic Acids: A Review

“…Recently published studies using this route discovered the synthesis of high-quality, RGO from GO and KOH, as well as Ag–GO nanocomposites from GO, KOH, and AgNO 3 in single fast steps, both of which have antibacterial properties . In a study, humidity sensors have been created using nanocomposites of GQDs and silver nanoparticles (AgNPs), which were produced using a hydrothermal process . In another work, the rapid and precise sensing of the S2-ion accomplished by creating a biosensor using a nanocomposite of fluorescent ionic liquid and GQDs (IL-GQDs) in a single process.…”

“… 62 In a study, humidity sensors have been created using nanocomposites of GQDs and silver nanoparticles (AgNPs), which were produced using a hydrothermal process. 63 In another work, the rapid and precise sensing of the S2-ion accomplished by creating a biosensor using a nanocomposite of fluorescent ionic liquid and GQDs (IL-GQDs) in a single process. The surface modification of GQDs by IL is done under hydrothermal conditions.…”

Recent Progress in Electronic Noses for Fermented Foods and Beverages Applications

“…Numerous gas sensors, a so-called sensor array, are the heart and most important component of the olfactory receptor. Various sensing materials, such as conducting polymers [38,39], carbon-based nanomaterials [40][41][42], metal oxides [43][44][45][46] and nanocomposites [47,48], have been used to adsorb odor molecules based on both physisorption and chemisorption. When the odor molecules adsorb on the sensing material surface, they lead to charge transfers, volume expansion, ion exchange or interaction with ion species that can cause changes in the electrical conductivity/resistivity of the sensing materials.…”