Narrow Results

Zn-doped SnO₂ nanoparticles have been synthesized by the chemical precipitation method with the Zn contents ($x$) of 1, 2 and 4 wt.%. The nanoparticles are crystalline in all cases, with the average particle size decreasing from 13.4 nm to 7.71 nm as the Zn concentration increases. The visible photoluminescence emission is observed in Zn-doped SnO₂ nanoparticles, with larger emission intensity at elevated Zn content. The dielectric constant has a strong doping dependence, which is evidently enhanced with increasing Zn content. Magnetization measurements reveal the enhancement in saturation magnetization and remanence magnetization, while the reduction in coercive field is observed with increasing amount of Zn dopant. The variation of optical, dielectric and magnetic properties is due to the incorporation of Zn in SnO₂ with smaller particle size and higher defect density. The present study clearly reveals the doping-induced ferromagnetism in Zn-doped SnO₂ nanoparticles, having applications in ultrahigh dielectric materials, high frequency devices and spintronics.

Regarding to the sustainability and green environment, many researchers have devoted to address the issues of chemical toxicity toward human and earth. This paper reports the fabrication of heterostructures comprised of tin oxide (SnO₂) and cerium oxide (CeO₂) by a facile co-precipitation method. For the first time, the obtained SnO₂@CeO₂ nanostructures were modified with lithium dopant with different mole ratios. The fabricated bare SnO₂, SnO₂@CeO₂, and Li–SnO₂@CeO₂ nanostructures were investigated by X-ray diffractometer (XRD), UV-visible spectrophotometer (UV–VIS), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM). The heterostructure preparation of the SnO₂@CeO₂ sample was verified by XRD and FT-IR analyses. The XRD results showed the tetragonal and cubic phases related to the SnO₂ and CeO₂, respectively. The suppression in bandgap from 2.51 eV to 2.22 eV on Li was estimated from Tauc plots obtained from the UV-VIS curve. Also, the Li–SnO₂@CeO₂ nanocomposite, when utilized as a catalyst for the degradation of Rhodamine B (RhB) during light irradiation, demonstrates a superior photodegradation performance of 92%, which is higher than all other fabricated catalysts.

We have investigated the effect of fluorine dopant concentration (0–15 F/Sn wt.%) on structural, optical and electrical properties of SnO₂ thin films grown by spray pyrolysis technique. According to the experimental evidences and data analysis, we found in these samples: (1) the polycrystalline layers, while in undoped conditions it mainly grow along (211) direction in doped ones (200) is the preferred direction with a direct band gap energy of about 3.7–3.9 eV; (2) The main cause for the relatively high absorption coefficients below E_g could be due to the presence of wide (~ 1–2 eV) band tails in the forbidden gap; (3) the highest (5.4 × 10^-3 Ω^-1) figure of merit belongs to the sample with 5 wt.% F/Sn concentration; (4) the grain boundary scattering is the main limiting mechanism in the electrical transport properties of the layers.

The laser ablation in liquid is a simple, easy, and less hazardous method available to create nanoparticles without chemical additives. In this paper, nanosecond laser ablation was conducted in various aqueous solvents to create tin oxide (SnO${}_2)$ nanoparticles from bulk SnO powder. After the laser ablation at 532 nm wavelength, the prepared samples were examined by UV–visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). UV–visible spectra showed that the significantly different absorption characteristics of nanoparticles are dependent on the original SnO amount in the solvent. The SEM observation clearly showed the creation of SnO₂ nanoparticles of about 10–20 nm in size with irregular shapes, which were found to be secondary nanoparticles from the TEM images. Interestingly, a three-dimensional octahedral structure with a size of 220–300 nm having the surface made of aggregates of fine nanoparticles was confirmed by TEM analysis. From the EDS spectra, it was clarified that the octahedral agglomeration is made from tin and oxygen, and the electron diffraction image confirmed the formation of the SnO₂ crystalline phase.

This paper reports the photocatalytic behavior of tin oxide (SnO₂) nanostructures prepared via three different aqueous solution-processed techniques: Precipitation, hydrothermal, and laser ablation. The prepared SnO₂ nanostructures were characterized by X-ray diffraction (XRD) and field electron scanning electron microscopy (SEM). The photocatalytic activity was evaluated by the oxidative degradation of rhodamine blue (RhB) under visible light. The SnO₂ nanostructure prepared by the laser ablation method exhibit significantly improved photocatalytic activity toward RhB due to the size and morphology of the prepared nanostructure.

Tin oxide nanoparticles with a narrow size distribution were prepared by pulsed laser ablation of a pure tin target both in aqueous solutions and in pure water. Laser beam of 266 nm, 355 nm and 532 nm from an Nd:YAG laser were applied and the wavelength effects on preparation of tin oxide particles were examined. The particle size and phase structure were characterized by using transmission electron microscope (TEM). The observation revealed that the particle size of the nanoparticles was about 2–5 nm. Chemical components of obtained nanoparticles were analyzed by using an energy dispersive X-ray analysis (EDX) and the results demonstrated that the nanoparticles mainly consisted of Sn and O elements. Furthermore, aqueous solutions of sodium dodecyl sulfate (SDS) were used to study the influence of surfactant concentration on the formation of tin oxide nanoparticles. When the surfactant reached critical micelle concentration, relatively stable colloidal suspensions consisting of well-dispersed tin oxide nanoparticles were obtained. UV-vis spectrometer was used to measure the absorption of suspensions of tin oxide nanoparticles.

Tin oxide thin films were prepared via spray pyrolysis method. The structural and morphological properties of SnO₂ thin films have been investigated using X-ray diffraction (XRD) and scanned electron microscope (SEM) analysis. The XRD pattern confirms the tetragonal rutile structure of SnO₂ with preferential orientation along (200) plane. SEM image reveals the nanocrystalline nature of the SnO₂ films. SnO₂ thin films were subjected to electrochemical tests to study the supercapacitor behavior. Maximum specific capacitance of 168 F/g at a scan rate of 25 mV/s was obtained using 0.5 M KOH as the electrolyte. This is the highest value ever reported for spray deposited tin oxide thin films.

Tin oxide (SnO₂)-doped Si nanorings of diameter in the range of 100 nm to 170 nm with an average width of 25 nm are synthesized by off-axis laser ablation (PLD) and are characterized by different techniques. The AFM observations show that the surface morphological features of films depend on the tin oxide concentration. The bandgap energies of undoped quantum dots are found to be 2.29 eV, while it decreases to 2.15 eV and 1.5 eV for 3 wt.% and 0.1 wt.% SnO₂-doped samples, respectively. The increase in the value of bandgap energy can be attributed to size reduction of particles. The Raman spectra of SnO₂-doped films are characterized by a broad Raman band with intensity maximum around 478 cm^-1. Raman spectrum shows frequency shift which may be due to changes in the Si–O bond length or Si–O–Si bond angle. The activation energy at higher temperature is found to be 16.99 meV for 3SnSi209, 21 meV for 0.1SnSi209 and 18.1 meV for undoped silicon which shows that defect levels are present in all the samples, the conduction is due to the presence of holes. The synthesized films exhibit PL peak in the visible region. The PL emission peak and PL intensity depend on dopants and it is concluded that luminescence does not originate from localized states in gap but from extended states. The size and shape of nanostructures depend on the SnO₂ concentration and the doping effects can be used as a significant guideline for tuning the electronic and optical properties of Si.

Highly ordered mesoporous antimony-doped tin oxide (ATO) materials, containing different amount of antimony in the range of 0–50mol%, are prepared via a nanoreplication method using a mesoporous silica template. The mesoporous ATO materials thus obtained exhibit high electrical conductivity, high reversible capacity, superior cycle stability and good rate capability as anode materials for lithium-ion batteries, compared to those of pure mesoporous tin oxide. Amongst the ATO materials in this work, the mesoporous ATO material with 10mol% of antimony has highest discharge capacity of 1940mAhg^-1 (charge capacity of 1049) at the 1st cycle, best cycle performance (716mAhg^-1 at 100th cycle) and excellent rate capability, which are probably due to the enhanced electrical conductivity as well as reduced crystalline size.

We introduce a two-step hydrothermal and microwave method to prepare novel SnO₂/MoS₂ composites. The as-prepared samples are well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The experimental results indicate that the SnO₂/MoS₂ composites are composed of MoS₂ nanosheets and ultrafine SnO₂ nanoparticles with mean size of 3–4nm which are well-distributed and anchored on the surface of MoS₂ nanosheets. The resultant composites demonstrate prominently improved electrochemical performances, which could be attributed to the unique and robust microstructures and synergetic effect between MoS₂ and SnO₂.

Sulfur-doped SnO₂ nanoparticles with ultrafine sizes have been successfully prepared by a one-pot hydrothermal method. The obtained samples are characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), thermogravimetric (TG), analyzer UV-Vis spectroscopy, photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the doping level of sulfur element as well as the bandgaps of SnO₂ can be controlled to a certain extent by varying the amount of L-cysteine (L-cys). When evaluated as photocatalysts in the degradation of rhodamine B (RhB) and reduction of Cr(VI) under visible light region, the resultant sulfur-doped SnO₂ nanoparticles demonstrate obviously enhanced photocatalytic activities due to the markedly improved visible light response and effective separation of the photo-generated electron–hole pairs.

A new synthetic route to ~4 nm grain-sized SnO₂ was proposed which involved a homogeneous precipitation in a deep eutectic solvent (DES) at room temperature. The white SnO₂ precipitate was obtained from SnCl₂ ⋅ 2H₂O dissolved DES by injecting slow drop-wise H₄N₂ ⋅ H₂O under stirring. The as-prepared nanocrystalline SnO₂ has a Brunauer–Emmett–Teller surface area of 65.12m²/g with an average Barretl–Joyner–Halenda pore diameter of 3.5 nm. As anode for lithium ion batteries, the nanocrystalline SnO₂ electrode delivered an initial charge capacity as high as 1045 mAh/g and its capacity retention is 58% after 30 cycles.

In this study, we proposed a portable electronic nose (e-nose) system based on a microcontroller (MSP430-FG439) combined with a tin oxide (SnO₂) gas sensor, which was heated by a cyclic heating method, to recognize the volatile organic compounds (VOCs). We had demonstrated that this e-nose system can classify and quantify VOCs, such as methanol and ethanol. The sensitivity of the e-nose system had good linearity in the concentration range of 10–40 ppm of these two VOCs, respectively. This portable e-nose system was implemented with a microcontroller acted as CPU, an LCD for displaying information of gases in real time, a wireless communication system, ZigBee, and a warning system.