Ruthenium (Ru) doped zinc oxide nanostructure-based radio frequency identification (RFID) gas sensors for NH3 detection

Abstract

Zinc oxide (ZnO) and ZnO:Ru nanopowdersare successfully synthesized using a 0.25м solution of zinc nitrate ((Zn(NO3)2), Diethanolamine (DEA)and different weight ratios of Ruthenium chloride hydrate (RuCl3)using the hydrothermal technique by autoclaving the solutions at 70 °C for 24 h. Different weight ratios (1, 5 and 10%) of Ru-doped ZnO gas sensors are fabricated which are sensitive to ammonia gas at room temperature for low gas concentrations. Field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) examined the produced nanopowders to investigate their morphological, chemical compositions and crystalline structures respectively. Some parts of an antenna tag for commercial UHF radio frequency identification (RFID) are lumped by the nanomaterials of undoped Zinc oxide and doped with Ruthenium to produce RFID gas sensors. With the same concentration of ammonia gas (100 ppm), different reflections and shift of peak frequency is measured for all the prepared tag sensors at room temperature. The tag with 5% Ru doping has the maximum change for resonance frequency which reaches to 940 MHz and maximum sensitivity of 35% with aresponse time of about 6.5 Sec. and recovery time of 15 Sec.

Keywords

• Doping
• Gas sensor devices
• Hydrothermal
• RFID
• ZnO:Ru
• Hierarchical nanostructure