In this study, zinc oxide (ZnO) was a very good candidate for improving the sensitivity of gas sensor technology. The preparation of an electrospun ZnO nanostructured thin film on a 433 MHz Rayleigh wave based Surface Acoustic Wave (SAW) sensor and the investigation of the acoustoelectric effect on the responses of the SAW sensor are reported. We prepared an electrospun ZnO nanostructured thin film on the SAW devices by using an electrospray technique. To investigate the dependency of the sensor response on the structure and the number of the ZnO nanoparticles, SAW sensors were prepared with different coating loads. The coating frequency shifts were adjusted to fall between 100 kHz and 2.4 MHz. The sensor measurements were performed against VOCs such as acetone, trichloroethylene, chloroform, ethanol, n-propanol and methanol vapor. The sensor responses of n-propanol have opposite characteristics to the other VOCs, and we attributed these characteristics to the elastic effect/acoustoelectric effect.

Significant progress has been made in two-dimensional material-based sensing devices over the past decade. Organic vapor sensors, particularly those using graphene and transition metal dichalcogenides as key components, have demonstrated excellent sensitivity. These sensors are highly active because all the atoms in the ultra-thin layers are exposed to volatile compounds. However, their selectivity needs improvement. We propose a novel gas-sensing device that addresses this challenge. It consists of two side-by-side sensors fabricated from the same active material, few-layer molybdenum disulfide (MoS₂), for detecting volatile organic compounds like alcohol, acetone, and toluene. To create a dual-channel sensor, we introduce a simple step into the conventional 2D material sensor fabrication process. This step involves treating one-half of the few-layer MoS₂ using ultraviolet–ozone (UV-O₃) treatment. The responses of pristine few-layer MoS₂ sensors to 3000 ppm of ethanol, acetone, and toluene gases are 18%, 3.5%, and 49%, respectively. The UV-O₃-treated few-layer MoS₂-based sensors show responses of 13.4%, 3.1%, and 6.7%, respectively. This dual-channel sensing device demonstrates a 7-fold improvement in selectivity for toluene gas against ethanol and acetone. Our work sheds light on understanding surface processes and interaction mechanisms at the interface between transition metal dichalcogenides and volatile organic compounds, leading to enhanced sensitivity and selectivity.

Borophene and silicene, two novel members of the Xene family, feature high surface reactivity and stability suitable for sensing applications. However, the

The synthesis and characterization of a novel covalent organic polymer cobalt (II) phthalocyanine (ATA-100) including tetra amino group is described for the first time. This covalent organic polymer (COP) is characterized by FTIR, TGA, RAMAN, PXRD, and SEM-EDS. The developed sensor is tested for acetone, ethyl butyrate, n-hexane, chloroform, and n-butyraldehyde in a range of 80-10,900 ppm. ATA-100 showed the highest sensitivity for ethyl butyrate. The results have confirmed the possibility of utilizing ATA-100 COP-based surface acoustic wave (SAW) sensors for a wide variety of applications, including indoor air quality and environmental monitoring of volatile organic compounds (VOCs).

Food safety is a crucial issue; all countries have struggled against pesticides for years. In this study, Polypyrrole (PPy)- and Polyacrylonitrile (PAN)-based non-enzymatic electrochemical sensors were investigated to detect the pesticide propamocarb (PM) in food samples. Under the experimental conditions, the proposed strategy exhibited a high selectivity of the disposable PPy-based and PAN-based sensors for the determination of propamocarb pesticide in the concentration of 1 μM with a rapid detection within 1 min at pH 7.4 and 25 °C. We demonstrated the detection of PM residues on cucumber and tomato samples with good electrochemical performances towards the real-time usability on real food samples. PAN-based non-enzymatic electrochemical sensor has good sensitivity, higher selectivity, and stability than PPy-based non-enzymatic electrochemical sensor. The prepared PAN-based non-enzymatic electrochemical sensor is a potential candidate to be used in devices which perform food safety in agricultural products.

In this study, borophene and nickel phthalocyanine (NiPc): borophene nanocomposites were prepared using the sonication method. The NiPc: borophene nanocomposite was uniformly obtained as a 10–80 nm-sized spherically shaped particle. Electrical conductivities (s) were measured as 3 × 10⁻¹³ Scm⁻¹ and 9.5 × 10⁻⁹ Scm⁻¹ for NiPc and the NiPc: borophene nanocomposite, respectively. The SEM image showed that borophene was homogeneously distributed in the NiPc matrix and increased the charge transport pathways. This is the main reason for a 10⁶-fold increase in electrical conductivity. An indium tin oxide (ITO)/NiPc: borophene nanocomposite-based thermoelectric generator (TEG) was prepared and characterized. The Seebeck coefficients (S) were calculated to be 5 μVK⁻¹ and 30 μVK⁻¹ for NiPc and the NiPc: borophene nanocomposite, respectively. A positive Seebeck coefficient value for the NiPc: borophene showed the p-type nature of the nanocomposite. The power factors (PF = sS2) were calculated as 7.5 × 10⁻¹⁶ μW m⁻¹ K⁻² and 8.6 × 10⁻¹⁰ μW m⁻¹ K⁻² for NiPc and the NiPc: borophene nanocomposite, respectively. Compositing NiPc with borophene increased the power factor by ~10⁶-fold. It has been concluded that the electrical conductivity and Seebeck coefficient of the NiPc: borophene material increases due to energy band convergence because of combining p-type NiPc with p-type borophene. Therefore, the NiPc: borophene nanocomposite is a promising material for TEG.