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In this study, leaf-like zinc oxide (ZnO) nanosheets were successfully synthesized by the microwave-assisted method through an easy, low-cost solvothermal process with annealing at 500 C. Characterization of the synthesized material revealed the mesoporous single-crystal leaf-like ZnO nanosheets with hexagonal wurtzite structure. Mesoporous and single-crystal structure of gas sensor could provide high surface area, which led to the di usion of gas molecules and improvement of gas sensitivity. Consequently, the gas-sensing function of the leaf-like ZnO nanosheets was tested for di erent types of Volatile Organic Compounds (VOCs). Sensitivity, stability, response, and recovery time of leaf-like ZnO nanosheets sensor for ethanol vapor were the best at 255 C. According to results, leaf-like ZnO nanosheets are a selective and sensitive sensor for ethanol vapor.

In this study, a surface plasmon resonance biosensor using angular interrogation based on a black phosphorene (BP) and graphene (G) heterostructure as two-dimensional materials are designed to enhance the sensitivity of conventional biosensors. The proposed structure is composed of eight layers: FK51A coupling prism, silver (Ag) thin film as the plasmonic metal, gold (Au) nanolayer in a protective role, BP nanosheets as an evanescent field enhancer, G monolayer as an immobilization process facilitator, DNA aptamer as biorecognition element, and phosphate buffered saline as a running buffer and sensing medium. To evaluate the performance of the proposed biosensor, analytical parameters such as minimum reflectivity (Rmin), sensitivity, as well as the full width at half-maximum (FWHM), detection accuracy (DA), and quality factor (QF) are systematically assessed by the use of the transfer matrix method analytically and the finite-difference time-domain method numerically, to validate each other. It is observed that the structure has been optimized with 1.49 (RIU) for the coupling prism and the heterostructure TiO2/Ag/Au/BP/G thicknesses of 65/35/1/3.18/0.34 nm, respectively. It was revealed that the proposed biosensor offered the sensitivity of 356 (°/RIU), QF of 42.4 (RIU−1), Rmin of 0.07 (a.u), FWHM of 8.3 (degree), and DA of 0.22 (unitless) and outperformed those of other results published up to now from the sensitivity point of view.