Correlation between optical characteristics and NO2 gas sensing performance of ZnO nanorods under UV assistance

Abstract

In this research, we present the ZnO nanorods synthesized through the simple route of the hydrothermal method. The ZnO nanorods were developed through the application of only zinc acetate Zn(CH3COO)2 and ammonia solution, NH4OH, in the hydrothermal process at 150oC for 10 hours. The size of the ZnO nanorods was defined as approximately 300 nm in diameter and 1-2 μm in length. The fabrication of sensors was achieved through drop-coating of synthesized ZnO nanorods on Al2O3 substrates integrated with Au electrodes. Subsequent to the process of sintering done at 500oC for different durations, ZnO nanorod-based sensors were investigated when exposed to NO2 gas (1.5, 2.5, and 5 ppm) at room temperature under continuous UV-LED (385 nm) illumination. The correlation between NO2 gas sensing performance and the optical property of the ZnO nanorods is discussed in detail. Herein, the defect concentration, particularly in the surface region of the ZnO nanorods could be modified through sintering, and this indicates its importance in the reduction of response-recovery times and enhancement of high sensitivity to NO2 gas.

Synthesis and Characterization of Zno Nanoparticles Using Hydrothermal and Sol-Gel Techniques for Dye-Sensitized Solar Cells

“…Hydrothermal (HT) method was used to synthesize the ZnO NPs [19]. 4 g of zinc acetate dihydrate, Zn(CH3COO)2.2H2O, (ZA) (99.9%, Merck Co.) was dissolved in 50 ml of methanol, CH4O, (99 %, SDFCL company, India) under vigorous stirring at 60 o C for 30 min followed by sonication for 20 min.…”

Convergence Gas Sensors with One-Dimensional Nanotubes and Pt Nanoparticles Based on Ultraviolet Photonic Energy for Room-Temperature NO2 Gas Sensing

“…Conventional ZnO-based gas sensors typically operate at high temperatures of 300-500 • C because sufficient thermal energy is required for surface reactions [27]. However, this negatively affects their stability and durability owing to the diffusion and sintering effect at the ZnO grain boundaries [17,28]. Therefore, a ZnO-based gas sensor with high responsivity at low operating temperatures should be developed.…”