Doped SnO2 Nanostructures Research Articles

Low-temperature/room-temperature gas sensing application for NO2 gas by SnO2 and Ni doped SnO2 nanostructures synthesized by sol-gel method

Gas sensors are the attentive parts for the day-to-day applications in advanced manufacturing, chemical industries and advanced applications need the better performing materials. SnO2 (wide band gap-3.27eV, n-type semiconductor) and Ni-doped SnO2 are the suitable materials for gas sensing in the fields of forward-looking technology. Pure and Ni-doped SnO2 particles were synthesized by sol-gel method and started with 0.2 mol of SnCl2, added with 2 ml of acetic acid, and pH controlled by the addition of 8 mol NaOH, till pH reaches desired value and Ni is doped. Finally washed, dried, and calcined at 400° C. The prepared pure and Ni(0.02 and 0.04 mol)-doped SnO2 nanostructures were characterized by XRD, EDAX, DSC, and SEM techniques. Average crystallite size is calculated by XRD and varied from 8 to 5 nm. Morphology shows difference, while the Ni concentrations changed. Particle size is estimated by transmission electron microscope (TEM), found to be 8–12 nm and well correlated with XRD analysis. The Energy gap is calculated with the UV–Vis spectrometer, and values are 3.21, 3.60, and 3.56 eV. Finally, the application part was carried out for NO2 gas sensing at a low level of 7–19 parts per million (PPM) at 40 °C, response and recovery times are 6 and 9 min respectively for all PPMs. Sensitivity of the samples of pure and Ni doped samples have 99 to 99.9 and 80 %. Pure and 0.02 mol Ni doped samples have the good achievement for sensitivity and 0.04 mol Ni doping has increase in conductance.

CO2 detection using In and Ti doped SnO2 nanostructures: Comparative analysis of gas sensing properties

This research explores the gas-sensing characteristics of undoped SnO2, as well as indium (In:SnO2) and titanium (Ti:SnO2) doped SnO2 nanostructures, which were synthesized using a homogeneous precipitation technique. Structural analyses indicate the presence of a tetragonal rutile phase with a preferred orientation along the (110) plane, with both doped samples showing shifts towards higher angles. Raman spectroscopy confirms the vibrational modes associated with SnO2 in both the pure and In: SnO2 samples, while the Ti: SnO2 sample reveals vibrational modes corresponding to both SnO2 and TiO2. Fourier-transform infrared (FTIR) spectroscopy indicates shifts in the O-Sn-O and Sn-O bonds in the doped samples, suggesting the effects of doping. X-ray photoelectron spectroscopy (XPS) results imply a combination of SnO and SnO2 phases in the undoped SnO2, while In: SnO2 samples display In-O bonding and the presence of metallic indium, and Ti: SnO2 shows Ti-O bonding. Scanning electron microscopy (SEM) images show agglomerated particles in the pure and In-doped samples, whereas the Ti-doped samples exhibit a flake-like structure. Transmission electron microscopy (TEM) analysis verifies the integration of dopants into the SnO2 crystal lattice, with average crystallite sizes measured at 44.46 nm for undoped, 34.06 nm for In: SnO2, and 42.63 nm for Ti: SnO2. Gas-sensing experiments for CO2 detection reveal that In: SnO2 demonstrates the most significant sensing response. These results underscore the impact of doping on the structural, morphological, and gas-sensing attributes of SnO2 nanostructures, offering important insights for the advancement of efficient carbon dioxide sensors.

Room Temperature-Built Gas Sensors from Green Carbon Derivative: A Comparative Study between Pristine SnO2 and GO-SnO2 Nanocomposite

Room temperature-built gas sensors were fabricated from graphene oxide (GO), pristine and doped SnO2 nanostructures. The as-synthesized green carbon derivative (GO) nanomaterials were prepared from waste plastic precursor using Modified Hummer’s methodology. Pristine SnO2 and GO-SnO2 nanocomposite were synthesized employing a wet synthesis technique known as co-precipitation. The as-prepared nanoparticles were investigated for structural crystallographic and morphological features using X-ray diffractometry (XRD) and Transmission electron microscopy (TEM) analytical techniques. High-angle annular dark field (HAADF) and elemental quantifications of the nanopowders were investigated with the Energy dispersive X-ray spectroscopy (EDX). Textural features were determined with the assistance of Brunauer-Emmett-Teller (BET) analyzer. Thermogravimetric analysis (TGA) was performed to ascertain the material stability and degradability of the synthetic materials. Functional group and bond structure analysis was conducted using Fourier-transform infrared (FTIR) spectroscopy. Gas sensor devices were tested for responses towards CH4, H2, LPG, and CO2 gases at 20 ppm concentrations of each. GO-SnO2 nanocomposite sensing device showed optimal detection response towards the respective analyte gases with values of 5.00, 5.08, 4.90 and 3.41 respectively. The prepared nanocomposite showed stability and selectivity towards the target gases in an order of magnitude of H2 > CH4 > LPG > CO2. The optimal gas sensor device’s dynamic gas sensing response was ascribed to the GO doping effect which relatively increased its surface area (46.48 m2g-1) and absorption sites.

Role of temperature on CdS and MoS2 doped SnO2 nanostructures: Potential applications in photodetection and temperature dependent current-voltage characteristics

The optical and electrical measurements in higher temperatures regime is a crucial issue. Although efforts are made to obtain optical and electrical characteristics at higher temperatures which have been achieved by optimizing various factors like (i) Type and dimensionality of the detecting materials (ii) operating wavelength and (iii) temperature regime. The present study investigates the role of temperature on the performance of an opto-electrical device derived from the nanostructure of a semiconductor oxide (SnO2) and chalcogenides (CdS and MoS2) along with their doped nanostructures. The proposed opto-electrical device is designed to make it simple, accurate, easy to operate, and cost-effective with enhanced performances at elevated temperature ranges from 30 ºC to 120 ºC. The optimized photodetection performance demonstrates its photoresponsivity of ∼6.3 mA W−1 for 390 nm wavelength. Other performance parameters such as detectivity of ∼8 × 108 jones at 405 nm wavelength and quantum efficiency ∼0.676 mA/Wm. The parameters obtained from synthesized material are superior to reported data. Improved photodetector performance is attributed due to the better structural, electronic, optical, and thermal behaviour of the nano dimension of chalcogenides (CdS, MoS2) and semiconductor oxide (SnO2). Apart from photodetection, electrical measurements were also carried out at varying temperature ranges from 30 to 120 ºC. The role of temperature was first evaluated using temperature dependent photoluminescence within the temperature regime (0–90 ºC). Although operating temperature above 90 ºC is a major issue for not allowing the device to operate above 120 ºC to avoid overheating the device and this limits it to show its best performance. The temperature dependent opto-electrical phenomenon was explained with the help of charge transfer across the interface between a silver electrode and nanostructures where dimensionality, operating temperature and nanostructures contribute significantly to the device performance. Hence, a trade-off is made with improved detection performance and operating temperature to qualify the expectations of the device to be competitive which has been justified through experimental results.

Insight into the adsorption, photocatalytic and magnetic properties of bandgap tailored hydrothermally grown SnO2:Ni/Cu nanostructures

Application of pristine and (2.5–5) wt% Ni, Cu doped SnO2 as adsorbent for the removal of Malachite green (MG) dye under natural solar light has been investigated in the present study. Synthesized nanostructures are characterised by XRD, XPS, BET, FESEM and UV–Visible spectroscopy. Sorption data were examined using Lagergren's pseudo first order, second order and intra particle diffusion kinetic models. Pseudo second order kinetic model was found suitable for describing the adsorption mechanism in this study. The calculated thermodynamic parameters revealed the endothermic, spontaneous and thermodynamically feasible nature of sorption mechanism of MG dye onto pristine and doped SnO2 nanostructures. Compared with other samples, 5% Cu doped SnO2 showed better photocatalytic degradation efficiency by removing 81.42% percentage of initial dye concentration within 240 min of contact time. SQUID measurement gave an account on the existence of ferromagnetic behaviour for Ni and Cu doped SnO2 nanostructures.

HIGHLY LUMINESCENT CU DOPED SNO2 NANOCOMPOSITES AND THEIR PHOTOCATALYTIC APPLICATION AS EXCELLENT METHYLENE DYE REMOVAL

Cu doped SnO2 nanostructures were grown using hydrothermal method. The solution was obtained by dissolving stannous chloride in distilled water (DW) with ammonium as surfactant followed by irradiation with ultrasonic vibrations. Obtained samples were characterized by structural, morphological and optical studies. All the peaks in the Xray diffractograms are identified and indexed as structure. In pure form of Cu nanoparticles shows crystalline structures and in high concentration of Cu in SnO2 nanoparticles shows the disappearing of peaks occurring as the pH increases. Negative slope of Williamson–Hall plots indicates compressive strain. Particle size of Cu doped SnO2 nanostructures decreases with increasingthe doping concentration. An optical study shows good luminescence in visible region. A strong quantum effect was evident from the far blue shifted optical direct and indirect band gap. 80% of MO dye removed from waste water.

Influence of La doping on structural, photo-luminescence and magnetic properties of SnO2 nanostructures co-doped with Gd

In this paper, we report the existence of defect induced room temperature ferromagnetism (RTFM) in (La, Gd) co-doped SnO2 nanostructures prepared by sol-gel method. The single phase rutile tetragonal structure (P42/mnm) of SnO2 was found to remain intact with doping as confirmed by X-Ray Diffraction (XRD) patterns with the average crystallite size in the range of 14–10 nm. Diffuse reflectance UV–vis reveals an increase in band gap energy of SnO2 on La and Gd doping. Further, all the SnO2 samples shows visible Photoluminescence (PL) emission in the region 424–525 nm associated with vacancies/defects. Further, the observed RTFM in doped SnO2 nanostructures is mainly due to presence of oxygen vacancies which is also supported by PL measurements.

Investigation the effect of Zn doping on structural and optical properties of SnO2

Herein, pure and Zn doped SnO2 nanostructures with different Zn-doping (1 wt%, 3 wt%, and 5 wt%), have been prepared by the hydrothermal method. Structural parameters of the prepared samples were measured by the X-ray diffraction (XRD). The obtained XRD results suggest high crystallinity and tetragonal rutile structure of the synthesized nanostructures. Also, the broadening and shifting in the peaks position on doping indicates the successful insertion of Zn ion into SnO2 crystal lattice. Energy Dispersive Spectroscopy (EDS) results confirms the presence of zinc in the Zn doped SnO2 nanostructures. Further, the spectroscopic analysis was also carried out using Raman, UV–visible and Photoluminescence Spectroscopy. All the prepared samples exhibit strong and broad Raman and PL peaks. In addition, the observed optical bandgap of the doped nanostructures is smaller than pure SnO2 nanostructures. The effect of zinc doping on structural and optical properties of SnO2 nanostructures have been studied and correlated.

Designing of screen-printed stannous oxide (SnO2) thick film sensors modified by cobalt and nitrogen elements for sensing some toxic gases and volatile organic compounds

The present research deals with fabrication of undoped SnO2, Co2+ doped SnO2 and nitrogen doped SnO2 nanostructures. These three materials were prepared by cost effective co-precipitation method. While the thick film sensors of the prepared materials was design by screen printing photolithography technique. The fabricated materials were characterized by several techniques. The structural properties of the screen-printed thick films measured by X-ray diffractometer (XRD), which confirms the formation of tetragonal SnO2 nanoparticles with average particle size between 15 and 17 ​nm. The morphological properties of fabricated thick of SnO2 were studied by scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) to get surface and lattice characteristics of prepared material. The EDS technique was utilized to get the elemental composition of the prepared thick film sensors. While the UV-DRS technique was used to get the band gap energy of undoped SnO2 and modified SnO2 sensors. Additionally, the materials were investigated by means of Brunauer-Emmett-Teller (BET) study, and from BET results the cobalt modified SnO2 has found to be higher surface area. These all-prepared sensors were applied for gas sensing results of NO2, LPG, CO and volatile organic compounds (VOC’S). The modified sensors found to be very effective at NO2 and VOC gas vapors with 80.23% and 69.13% gas response for cobalt modified SnO2 was observed. The tested gases NO2 and VOC found to be very selective modified sensors. Reusability and recycling results demonstrate that Co2+ doped SnO2 is very efficient, long time stable and reproducible sensor at NO2 and VOC gases at minimum gas concentration and moderate temperature.

Designing of Screen-Printed Stannous Oxide Thick Film Sensors Modified by Cobalt and Nitrogen for Sensing Some Toxic Gases and Volatile Organic Compounds

The present deals with fabrication of undoped SnO2, transition metal Co2+ doped SnO2 and non-metal nitrogen doped SnO2 nanostructures. These three materials were prepared by cost effective co-precipitation method. While the thick film sensor was design by screen printing photolithography technique. The fabricated materials were characterized by several techniques. The structural properties of the screen-printed thick films measured by X-ray diffractometer (XRD), which confirms the formation of tetragonal SnO2 nanoparticles with average particle size between 15 -17 nm. The morphological properties of fabricated thick of SnO2 were studied by scanning electron microscopy (SEM), and HR-TEM to get surface and lattice characteristics of prepared material. The EDS technique was utilized to get the elemental composition of the prepared thick film sensors. While the UV-DRS technique was used to get the band gap energy of undoped SnO2 and modified SnO2 sensors. Since, the sensors effectively work over the surface, hence the prepared sensors were investigated by BET) study, from BET results the cobalt modified SnO2 found to be higher surface area. These all-prepared sensors were applied for gas sensing results of NO2, LPG, CO and volatile organic compounds (VOC’S). The modified sensors found to be very effective at NO2 and VOC gas vapours with 80.23 % and 69.13% gas response for cobalt modified SnO2 was observed. The tested gases NO2 and VOC found to be very selective modified sensors. Reusability and recycling results demonstrate that Co2+ doped SnO2 is very efficient, long time stable and reproducible sensor at NO2 and VOC gases.

Pr doped SnO2 nanostructures: Morphology evolution, efficient photocatalysts and fluorescent sensors for the detection of Cd2+ ions in water

We report the effect of Pr doping on structural, morphological, optical, photocatalytic properties and heavy-metal ion sensing behavior of 3D flower-like SnO2 nanostructures synthesized using hydrothermal method by varying Pr concentration from 0 to 10 mol%. The synthesized samples have been characterized by various analytical techniques. The results indicate that the morphology of SnO2 nanostructures can be tailored by changing the Pr-dopant concentration in a reasonable range. Crystallographic studies reveal the lattice distortion with an increase in Pr doping concentration in SnO2 host lattice. Moreover, the photocatalytic activity of SnO2 studied by the degradation of Rhodamine-B (RhB) dye in aqueous media shows excellent performance on 10 mol% praseodymium doping, which may be attributed to its specific morphology, smaller size and larger surface area as seen from BET measurements. Further, the sensors based on 10 mol% Pr-doped SnO2 nanostructures shows highest fluorescence quenching efficiency (0.22) as compared to pure SnO2 and other doped samples at lowest concentration of Cd2+ (0.01 μg/ml) in drinking water with Limit of Detection (LOD) as low as 0.008 μg/ml. The possible formation mechanism of Pr-doped SnO2 nanostructures and the heavy metal-ion sensing mechanism of sensors has been proposed and discussed in detail.

New insights towards strikingly improved room temperature ethanol sensing properties of p-type Ce-doped SnO2 sensors

In this article, room temperature ethanol sensing behavior of p-type Ce doped SnO2 nanostructures are investigated successfully. Interestingly, it is examined that the abnormal n to p-type transition behavior is caused by Ce doping in SnO2 lattice. In p-type Ce doped SnO2, Ce ion substituting the Sn is in favor of generating excess holes as oxygen vacancies, which is associated with the improved sensing performance. Although, p-type SnO2 is one of the important materials for practical applications, it is less studied as compared to n-type SnO2. Pure and Ce doped SnO2 nanostructures were successfully synthesized by chemical co-precipitation method. The structure, surface morphology, unpaired electrons (such as free radicals), and chemical composition of obtained nanoparticles were studied by various kinds of characterization techniques. The 9% Ce doped SnO2 sensors exhibit maximum sensor response of ~382 for 400 ppm of ethanol exposure with fast response time of ~5 to 25 sec respectively. Moreover, it is quite interesting that such enhancement of ethanol sensing is unveiled at room temperature, which plays a key role in the quest for better ethanol sensors. These remarkably improved sensing results are attributed to uniformly distributed nanoparticles, lattice strain, complex defect chemistry and presence of large number of unpaired electrons on the surface.

Role of Cu in engineering the optical properties of SnO2 nanostructures: Structural, morphological and spectroscopic studies

We have carried out a systematic study to investigate the effect of Cu doping on the optical properties of SnO2 nanostructures synthesized by chemical route. Synthesized nanostructures were characterized using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), High resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray spectroscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, UV–visible and Photoluminescence (PL) spectroscopy. The Rietveld refinement analysis of XRD patterns of Cu-doped SnO2 samples confirmed the formation of single phase tetragonal rutile structure, however some localized distortion was observed for 5 mol% Cu-doped SnO2. Crystallite size was found to decrease with increase in dopant concentration. FE-SEM images indicated change in morphology of samples with doping. HR-TEM images revealed that synthesized nanostructures were nearly spherical and average crystallite size was in the range 12–21 nm. Structural defects, crystallinity and size effects on doping were investigated by Raman spectroscopy and results were complemented by FTIR spectroscopy. Optical band gap of samples was estimated from reflectance spectra. We have shown that band gap of SnO2 can be engineered from 3.62 to 3.82 eV by Cu doping. PL emission intensity increased as the doping concentration increased, which can be attributed to the development of defect states in the forbidden transition region of band gap of SnO2 with doping. We have also proposed a band model owing to defect states in SnO2 to explain the observed PL in Cu doped SnO2 nanostructures.

A Study of the CO Sensing Responses of Cu-, Pt- and Pd-Activated SnO₂ Sensors: Effect of Precipitation Agents, Dopants and Doping Methods.

In this work, we report the synthesis of Cu, Pt and Pd doped SnO2 powders and a comparative study of their CO gas sensing performance. Dopants were incorporated into SnO2 nanostructures using chemical and impregnation methods by using urea and ammonia as precipitation agents. The synthesized samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM). The presence of dopants within the SnO2 nanostructures was evidenced from the HR-TEM results. Powders doped utilizing chemical methods with urea as precipitation agent presented higher sensing responses compared to the other forms, which is due to the formation of uniform and homogeneous particles resulting from the temperature-assisted synthesis. The particle sizes of doped SnO2 nanostructures were in the range of 40–100 nm. An enhanced sensing response around 1783 was achieved with Cu-doped SnO2 when compared with two other dopants i.e., Pt (1200) and Pd:SnO2 (502). The high sensing response of Cu:SnO2 is due to formation of CuO and its excellent association and dissociation with adsorbed atmospheric oxygen in the presence of CO at the sensor operation temperature, which results in high conductance. Cu:SnO2 may thus be an alternative and cost effective sensor for industrial applications.

Synthesis of undoped and Fe nanoparticles doped SnO2 nanostructure: study of structural, optical and electrocatalytic properties

In this study, undoped and nano Fe doped SnO2 nanostructures were synthesized by hydrothermal method. Characterization of the synthesized nanostructures was performed by X-ray diffraction and scanning electron microscopy. For investigation of optical properties, photo luminescence and UV–Vis spectrum were taken. The electrochemical response of the carbon paste electrode modified with synthesized nanostructures toward levodopa (L-Dopa) was studied. Cyclic voltammetry studies using prepared modified electrodes showed outstanding electrocatalytic properties towards electro-oxidation of L-Dopa and a significant reduction was observed in anodic over voltage compared to the bare electrode. Obtained results indicated the effective role of the employed dopant. Best response in terms of the current enhancement, overvoltage reduction, and reversibility improvement of the L-Dopa oxidation reaction under experimental conditions was obtained by modified electrode with Fe doped SnO2 nanoparticles.

Indium doped SnO2 nanostructures preparation and properties supported by DFT study

Indium doped tin dioxide nanostructures are investigated using experimental and theoretical techniques. XRD, UV-Vis and Raman spectroscopy are used to examine indium doped SnO2 nanostructures with various doping ratios. On the other hand Density functional theory (DFT) is used to check and compare lattice constants, energy gaps and vibrational properties. Large unit cell and previously suggested pyramid clusters of metal dioxides are applied to doped SnO2 and tested to manifest properties of different pure and doping stoichiometries. SnO2 clusters results show oxygen-deficient stoichiometry in agreement with experiment and previous literature. Experimental results of In doped SnO2 show and increase of lattice constants and a decrease of energy gap. The same trend is observed using DFT calculations for energy gap. Theoretical Large unit cell results show nearly the same lattice constant before and after In doping that indicate a change in experimental stoichiometry due to doping. The highest Raman peek at 581 cm−1 encounter blue shifting to 585 cm−1 due to In doping using DFT cluster calculations in comparison with 563–582 cm−1 experimental shift.

Effect of cobalt concentration on morphology of Co-doped SnO2 nanostructures synthesized by solution combustion method

Cobalt (Co) doped SnO2 nanostructures were synthesized by solution combustion synthesis and structural and optical properties were investigated. The morphology of SnO2 nanostructure was changed from nanoflakes to nanospheres via nanorods and crystallite size was reduced from 4.7 nm to 2.7 nm as increase of Co doping concentration. The obvious diffraction peaks of X-ray diffraction and clear lattice fringes confirmed the formation of rutile phase of SnO2. The absorption edge transfers to upper wavelengths and energy bandgap was found to be decreasing by increase of Co concentration. The observed absorption band shows the characteristic band of d–d transitions of Co2+ ions in octahedral site symmetry. Vibrational spectroscopy shows the characteristic absorption peaks of Sn–O and confirms the incorporation of Co ions in SnO2 lattice.

Synthesis Of Novel Al-doped SnO2 Nanobelts With Enhanced Ammonia Sensing Characteristics

Pure and Al-doped single-crystalline 1-D SnO2 based nanostructures were synthesized via a catalyst free simple chemical vapour transport and condensation process in Ar/O2 atmosphere. The crystalline structure, morphology and defect states of pure and Al- doped SnO2 nanostructures have been investigated in detail. Incorporation of Al in the interstitial voids of tetragonal SnO2 lattice is proved by investigating through various analytical techniques. Al doping in SnO2 significantly increases its defect concentration as demonstrated by photoluminescence spectra. The PL spectra for pure and Al-loaded SnO2 samples shows a less intense excitonic peak at ~384 nm in the UV region apart from the broad and intense yellow emission peak centred at around ~596 nm and a shallow peak at ~672 nm, respectively. For the development of stable and economically viable sensor modules for ammonia vapour detection, sensitivity at three different concentration of NH3 vapours (25ppm, 50 ppm and 100 ppm) were investigated by varying the operating temperature (250-400 °C). The minimum sensitivity for Al-doped SnO2 nanobelts was found to be 0.47 (at 25 ppm and 250 °C) and the maximum as 1.85 (at 100 ppm and 350 °C), which is 2-3 times higher than that for pure SnO2 nanowire assembles. Our results are found to be reproducible after cross examination by repeated observations. The response time (35-110 s), and recovery time (50-120 s) of our Al-doped SnO2 nanostructured sensors, for different concentrations of NH3 vapours, are equivalent or less if compared to those of available metal-oxide sensors in market. Copyright © 2015 VBRI press.

Synthesis of SnO2 nanostructures by ultrasonic-assisted sol–gel method

Fluorine doped SnO2 nanostructures were grown using ultrasonic assisted sol–gel method. The gel was obtained by dissolving stannous chloride in methanol with ammonium fluoride as dopant followed by irradiation with ultrasonic vibrations. Obtained samples were characterized by structural, morphological and optical studies. All the peaks in the X-ray diffractograms are identified and indexed as tetragonal cassiterite structure. Negative slope of Williamson–Hall plots indicates compressive strain. Particle size of SnO2 nanostructures is decreases with increases in concentration of fluorine doping. Atomic force microscopy, scanning electron microscopy and transmission electron microscopy studies confirm the formation of ring like porous structures and then hollow tube like growth with increase in the fluorine concentration. Peaks in Raman spectra also indicate strong confinement in SnO2 particles. Distinct peaks in the PL spectra make the structure suitable for photovoltaic applications.

Energy band structure investigation of blue and green light emitting Mg doped SnO2 nanostructures synthesized by combustion method

Tin oxide (SnO2) and Mg doped (2, 4, 6, and 8wt%) SnO2 nanoparticles were synthesized by the self-propagating solution combustion synthesis using citric acid as fuel. The characterization of samples was done by X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), UV–visible spectroscopy, SAED and photoluminescence (PL). XRD pattern and TEM studies show that the synthesized particles are of average size 30nm and they are in tetragonal rutile structure of SnO2. Combined blue and green emission is seen in 4wt% Mg doped SnO2 and intensity of blue band is increased with respect to increase in Mg dopant concentration which is attributed to increase in population of oxygen vacancies. The PL emission in blue and green region is due to the doubly charged state (Vo2+) of oxygen and tin interstitial defects respectively and is explained with an energy band diagram.