Electrical properties of acetone imprinted hematite nanomaterials doped with Pd & Ag for gas sensing and simulation of their wireless devices.

This article presents a novel technique for wireless hydrothermally improved gas sensor devices enhanced by molecular imprinting technique (MIT) for hematite nanomaterials with the existence of acetone using different ratios (10 %, 15 %, and 25 %) as well as doping with palladium/ silver to detect the imprinted gas. α-Fe 2 O 3 are characterized utilizing field emission scanning electron microscope (FESEM), photoluminescence, Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photo-spectroscopy (XPS), and High-Resolution Transmission Electron Microscopy (HRTEM), Thermogravimetric Analysis (TGA) and utilizes Brunauer-Emmett-Teller (BET) to ascertain their shape, optical properties, and values for surface area and thermal characteristics, respectively. Depending on the preparation conditions, non-regular cubes and rods have typical particle sizes ranging from 25 to 120 nm, acetone imprinted and doped with palladium sample (Ap) offers smaller particles than acetone imprinted sample (A15) making adsorption easier. Where XRD showed all diffraction peaks for α-Fe 2 O 3 as well as XPS authorized the oxidation state, also FTIR showed the characteristic peaks of the stretching mode Fe-O which indicates the formation of α-Fe 2 O 3. Lower defects for (Ap) as it has the highest intensity of 176.15 a.u. in the photoluminescent spectrum, for TGA analysis results explain that pure sample has more thermal stability and lower weight loss. Six hematite films are fabricated using the spin coating technique where acetone molecules are presented during the synthesis process of the nanomaterials to imprint their shapes on the surface of hematite. By measuring the response of the gas sensors and their electrical properties, the I-V curve for Ap showed a rectifying behavior and its shunt resistance (Rsh) is higher than series resistance (Rs) which ensures a high response of (115 %). To develop a wireless gas sensor COMSOL Multiphysics software 5.3(a) software is used for the simulation of three devices model by depositing a layer by specified dimensions of hematites (A15, As, and Ap) with their different electrical conductivities on the surface of rectangular patch antenna by showing geometry, the microstrip patch antenna bandwidth, resonant frequency, scattering parameters, and radiation patterns in the E-plane and 3-D far-field pattern and directivity is calculated also, Sp gives improved reflection coefficient, gain quality factor and directivity due to its high electrical conductivity. • Hydrothermal synthesis of hematite molecularly imprinted with acetone, doped with palladium and silver. • Fabrication of gas sensor devices using spin coating for acetone detection. • Investigated synergistic effects of molecular imprinting and doping on hematite to improve sensor sensitivity. • Designed a wireless gas sensor with a patch antenna, optimizing performance using nanomaterials A15, Ap, and As. [ABSTRACT FROM AUTHOR]