Low- cost solution combustion synthesis of highly sensitive ammonia sensing device based on Zn doped SnO2 nanostructures
摘要
In this present work, nanoparticles of Zn-doped SnO2 nanostructures were synthesized using a low-cost solution combustion synthesis method. The structural analysis and morphological properties with elemental composition of synthesized samples were characterized via X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) respectively. XRD investigations confirm the tetragonal rutile structure with a reduction in average crystallite size from 8.63 nm to 7.06 nm with an increase of Zn2+concentration. FESEM with energy dispersive X-ray spectroscopy (EDS) confirms the formation of nanoparticles without any impurity. UV–Visible studies show a reduction in band gap energy values from 3.71 eV to 3.38 eV with an increment in concentration of Zn. Fourier transform infrared spectroscopy (FTIR) corresponds to O–H, C–H, Sn–OH, and Sn–O–Sn functional groups and confirms the creation of pure phase SnO2. Photoluminescence spectra (PL) of Zn-doped SnO2 nanostructures analyze the near band edge emission or UV emission at 454 nm and a green emission at 524 nm, confirming the excess of oxygen vacancies within the host structure. Raman spectra also confirm the abatement of crystallite size and existence of flaws like oxygen vacancies. These defects significantly influence the interaction of gas molecules with the surface of the sensing layer. The I–V (current–voltage) characteristics of the paper-based sensing device fabricated using Zn-doped SnO2 nanostructures were examined to investigate its response in the ammonia environment with regard to varying exposure time. An increase in electric current was observed at a specific applied voltage when the Zn-doped SnO2 nanostructured layer on Whatman paper was exposed to ammonia fumes, demonstrating its oxidizing nature. Only qualitative mode is used in these sensing studies.