Influence of In doping on the structural, photo-luminescence and alcohol response characteristics of the SnO2 nanoparticles

Graphical abstract: When the sample is exposed to air, the atmospheric oxygen O{sub 2} adsorbs on the sample surface in the form of ionic species O{sup −} by capturing electrons from the conduction band. The adsorbed ionic species O{sup −} react with the test alcohol molecules and are responsible for sensing mechanism. - Highlights: • In-doped SnO{sub 2} samples show smaller crystallinity with crystallite size: ∼7–9 nm. • EDX analyses confirm the incorporation of indium ions in the SnO{sub 2} lattice. • Raman spectra are consistent with the results of XRD and SAED pattern. • Alcohol response has been found to increase with the indium dopant concentration. • 3 at% In-doped sample exhibits maximum response (96.5%) to propan-2-ol at 250 °C. - Abstract: Undoped and In-doped SnO{sub 2} nanoparticles were synthesized by the co-precipitation method. Upon In doping, the samples exhibit reduced crystallinity as compared to the undoped SnO{sub 2}. The Raman spectra of the undoped samples exhibit three fundamental peaks at 467.3, 633.4 and 774.6 cm{sup −1} corresponding to E{sub g}, A{sub 1g} and B{sub 2g} vibration modes, respectively. The PL spectra show two strong emission bands at the wavelengths 417 nm and 479 nm, along with five weakmore » emission peaks in the visible region. Alcohol response characteristics of the In-doped SnO{sub 2} samples were investigated for various concentrations (10–50 ppm) at different operating temperatures (150–250 °C). Among all the samples examined, the 3 at% In-doped SnO{sub 2} sample shows maximum response (96.5%) to propan-2-ol, followed by ethanol (92%) and methanol (90%) at the operating temperature of 250 °C for 50 ppm concentration. For each test alcohol, the response has been found to increase with the In dopant concentration.« less