The relationship between the solid content of rGO and SnO2 nanoparticles, annealing temperature, and sensor performance was studied. In this work, a new spraying platform with a simple structure, low cost, and good film-forming consistency was designed and built to make a sensitive film (rGO/SnO2) for NO2 gas sensors. Due to the advantages of real-time, high portability and accuracy of the functionalized HGGT sensor, it demonstrates a promising platform for constructing biosensors for many other analytes.įlexible sensors used to detect NO2 gas generally have problems such as poor repeatability, high operating temperature, poor selectivity, and small detection range. Compared with normal solution-gated graphene transistors, employment of hydrogel as a source of electrolytes greatly enhances the portability of the sensor, and facilitates functionalization with enzymes and nanomaterials. 0.046 ppm), and has been successfully applied to breath alcohol test after drinking. The HGGT based alcohol sensor exhibited an excellent sensitivity with a very low detection limit down to 1 μM (i.e. The sensing mechanism of the AOx/CNs functionalized sensor lies in the oxidation reaction of alcohol by AOx and the electrocatalytic oxidation reaction of the generated H2O2. In this work, we constructed a breath alcohol biosensor based on a hydrogel-gated graphene field-effect transistor (HGGT) with chlorella derived layered carbon nanosheets (CNs) and alcohol oxidase (AOx) embedded in the hydrogel. The inspection of drunk driving has become an effective measure to reduce the occurrence of traffic accidents. A study of characteristics sensitive to NO2 (0.1–50 ppm) showed that gas sensors based on the ZnO-SnO2 film demonstrated a high sensitivity to NO2 with a concentration of 0.1 ppm at an operating temperature of 200 ☌. The presence of a strong surface electric field leads to the best gas-sensitive properties: the sensor’s responsivity is between two and nine times higher than that of sensors based on ZnO-SnO2 films of other compositions. Measurements of ZnO-SnO2 films containing 0.5 mol.% ZnO showed the existence of large values of surface potential, up to 1800 mV, leading to the formation of a strong surface electric field with a strength of up to 2 × 107 V/cm. The obtained films are up to 200 nm thick and consist of ZnO-SnO2 nanocomposites, with ZnO and SnO2 crystallite sizes of 4–30 nm. The resulting gas-sensitive ZnO-SnO2 films were comprehensively studied by atomic force microscopy, Kelvin probe force microscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Gas sensors based on the multi-sensor platform MSP 632, with thin nanocomposite films based on tin dioxide with a low content of zinc oxide (0.5–5 mol.%), were synthesized using a solid-phase low-temperature pyrolysis technique.

Sno2 core shell