Green synthesis of tin oxide based nanoparticles using Terminalia bellirica seed extract: impact of operating temperature and antimony dopant on sensitivity for carbon dioxide gas sensing application

Green synthesis of undoped tin oxide (SnO2) and 2 wt% antimony doped tin oxide (Sb:SnO2) for carbon dioxide (CO2) gas sensing application is reported. The structural, morphological and optical properties of nanoparticles were investigated using XRD, SEM, EDX, HRTEM, FTIR and UV-Vis characterisation techniques. CO2 gas sensing studies were carried out by using calibration setup on pellets of nanoparticles. From XRD, SEM and HRTEM analysis, the average size of Sb:SnO2 nanoparticles were found decreased than the SnO2 nanoparticles. EDX analysis indicated the presence of tin, antimony and oxygen elements in the structure of nanoparticles. The presence of functional groups responsible for the formation of nanoparticles was identified by FTIR spectra. Bandgap of SnO2 and Sb:SnO2 nanoparticles was found to be 3.67 eV and 3.47 eV respectively. The sensitivity of SnO2 and Sb:SnO2 nanoparticles at the optimized operating temperature was found as 18.32% and 35% at 1000 ppm CO2 gas concentration

The effect of tin concentration on microstructural, optical and electrical properties of ito nanoparticles synthesized using green method

Indium tin oxide (ITO) nanoparticles were synthesized by green combustion method using indium (In) and tin (Sn) as precursors, and Carica papaya seed extract as novel fuel. This paper highlights effect of tin concentration (5%, 10% and 50%) on microstructural, optical and electrical properties of ITO nanoparticles (NPs). The indium nitrate and tin nitrate solution along with the fuel were heated at 600 °C for 1 h in muffle furnace and obtained powder was calcinated at 650 °C for 3 h to produce ITO NPs. The above properties were investigated using XRD, FTIR, UV-Vis spectroscopy, SEM, TEM and computer controlled impedance analyser. The XRD, SEM and TEM investigations reveals the synthesized NPs were spherical in shape with an increase in average grain size (17.66 to 35 nm) as Sn concentration increases. FTIR investigations confirms the In-O bonding. The optical properties results revealed that the ITO NPs band gap decreased from 3.21 to 2.98 eV with increase in Sn concentration. The ac conductivity of ITO NPs was found to increase with increase in Sn concentration. These synthesised ITO NPs showed the excellent properties for emerging sensor and optical device application

Green synthesis of ITO nanoparticles using Carica papaya seed extract: impact of annealing temperature on microstructural and electrical properties of ITO thin films for sensor applications

This paper reports the synthesis of indium tin oxide (ITO) nanoparticles and the effect of annealing temperature on the microstructural and electrical properties of ITO thin films. The synthesized ITO (90:10) nanoparticles are deposited at 29°C using E beam evaporation to form ITO thin films and annealed at 200, 400 and 500°C. The microstructural properties are investigated using XRD and AFM , and electrical properties such as temperature coefficient of resistance (TCR) and gauge factor are investigated using four-probe and four-point beam bending method, respectively. The investigations results reveal an increase in grain size, carrier concentration and gauge factor with an increase in the annealing temperature. The absolute value of TCR is constant at high temperatures for the film annealed at 500°C. The ITO thin film annealed at 500°C shows improved morphological and electrical properties and can be used for the development of sensors operating at high temperature