Radhakrishnan Reshma P, Prasad Arun K
Nanomaterials Characterization and Sensors Section, Surface and Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, A CI of Homi Bhabha National Institute, Kalpakkam 603102, Tamil Nadu, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Feb 15;287(Pt 1):122092. doi: 10.1016/j.saa.2022.122092. Epub 2022 Nov 12.
In the present study, a multi-modal approach consisting of in-situ photoluminescence, Raman, and UV-Vis absorption spectroscopic studies is carried out along with chemiresistive sensing to unveil the mechanism of NH gas sensing by VO nanoparticles in ambient air. VO nanoparticles with an average size of 49 nm show a superior sensor response of 17 ± 1.5 % towards 1 ppm of NH gas with a response and recovery time of 96 s and 45 s, respectively. The photoluminescence and UV-Vis absorption studies in the presence of NH reveal electron doping to a new energy level at 1.84 eV, resulting in conduction band filling and increase in the optical band gap. The intensity of the photoluminescence spectrum shows an increase in the presence of NH gas as a result of this electron doping. The sensor response from the optical sensing carried out by in-situ photoluminescence study is 43 % for 40 ppm of NH gas. The vanadyl oxygen site is the most active in the sensing process, as evident by a selective enhancement in the intensity of V-O (vanadyl) bond vibration. This study gives an experimental evidence for the changes in optical and electronic properties of VO on the adsorption of NH gas molecules.
在本研究中，采用了一种多模态方法，包括原位光致发光、拉曼光谱和紫外 - 可见吸收光谱研究，并结合化学电阻传感，以揭示环境空气中VO纳米颗粒对NH₃气体传感的机制。平均尺寸为49 nm的VO纳米颗粒对1 ppm的NH₃气体表现出17±1.5%的优异传感器响应，响应时间和恢复时间分别为96 s和45 s。在NH₃存在下的光致发光和紫外 - 可见吸收研究表明，电子掺杂到1.84 eV的新能级，导致导带填充和光学带隙增加。由于这种电子掺杂，光致发光光谱的强度在NH₃气体存在时增加。通过原位光致发光研究进行的光学传感对40 ppm的NH₃气体的传感器响应为43%。钒氧基位点在传感过程中最为活跃，这从V - O（钒氧基）键振动强度的选择性增强中可以明显看出。本研究为NH₃气体分子吸附时VO的光学和电子性质变化提供了实验证据。
