Mn-doped SnO2 Research Articles

Structural and magnetic behavior of Mn-doped SnO2 nanorods for diluted magnetic semiconductors

Structural and magnetic behavior of Mn-doped SnO2 nanorods for diluted magnetic semiconductors

Ferromagnetism, bandgap, and impedance analysis of Mn-doped SnO2 synthesized by single-step wet chemical approach

Ferromagnetism, bandgap, and impedance analysis of Mn-doped SnO2 synthesized by single-step wet chemical approach

Phyto-synthesis of Pure and Mn Doped SnO2 Nanoparticles: Evaluation of Antimicrobial, Antioxidant and Photocatalytic Activities

Phyto-synthesis of Pure and Mn Doped SnO2 Nanoparticles: Evaluation of Antimicrobial, Antioxidant and Photocatalytic Activities

Effect of Mn doping on structural, optical and photocatalytic properties of SnO2 nanoparticles

The bare and Mn-doped SnO2 products were prepared using a simple chemical precipitation process, which was discussed in the preparation aspect. XRD, SEM with EDS, TEM, and HRTEM studies were used to analyse the obtained Mn-doped SnO2. According to the UV-DRS data, SnO2 from Mn doping significantly reduced its band gap. The photoluminescence emissions of doped SnO2 exhibit an intensity reduction caused by the cross-relaxation process when compared to pure SnO2. The photocatalytic degradation of brilliant green (BG) using a bare SnO2 and Mn doped sample was investigated under visible light illumination. The Mn-doped SnO2 sample demonstrated a greater level of degradation (92.84%) due to its increased surface area (32.70 m2/g) and lower band gap (3.57 eV), which prevent the recombination of photogenerated charge carriers.

The cationic interstitials induced resistive switching: a case study on Mn-doped SnO2

This work has explored the possible defects in Mn-doped SnO2 and compared the effects of interstitial Mn and oxygen vacancies on the electronic structure of SnO2. Combining the DFT calculations and experimental measurements, we found that when the Mn-doped SnO2 is synthesised under Sn-rich or O-poor conditions, the defect pair of Mn substitution and interstitial rather than oxygen vacancy will be formed, which induces energy band across the Fermi level and significantly affects the electronic structure of SnO2. With the Mn interstitials, stable intrinsic multi-level resistive states and optical SET can be achieved in the Mn-doped SnO2 memristors. This result can provide guidance in the fabrications of defective metal oxides and promote the investigations on cationic interstitial triggered multi-level resistive switching and optoelectronic memristors.

Design of Mn-SnO2 double-shell nanostructures for high-performance acetone gas sensor

• High-performance acetone sensor of double-shelled Mn-SnO 2 was prepared. • The response of Mn-SnO 2 towards acetone was as high as 75. • Mn-SnO 2 sensing mechanism was also discussed. In this study, a simple method to fabricate Mn-doped SnO 2 double-shell nanofibers by electrospinning was presented. The results demonstrated that Mn-SnO 2 nanofibers were unique tube-in-tube structures and possessed a high response of 75 towards 100 ppm acetone, which was higher three times than that of pure SnO 2 . It was believed that the excellent gas sensing properties of the sensor were that Mn-dopant dramatically enhanced the percentage of the defect-related oxygen species. The promising hollow double-shell structure was beneficial to gas absorption and penetration of oxygen and acetone molecules by offering more active sites. Hence, the Mn-doped double-shell nanofibers exhibited a promising application prospect in efficient sensing material in the future.

Density Functional Theory Study on Magnetic character and Mn Crystal Field Split Levels in Mn-doped SnO Monolayer

Density Functional Theory Study on Magnetic character and Mn Crystal Field Split Levels in Mn-doped SnO Monolayer

Optical and electrical properties of pure and doped tin oxide nanoparticles

Optical and electrical properties of pure, Co- and Mn-doped tin oxide (SnO2) nanoparticles (NPs) were studied and reported. The materials were successfully prepared by simple co-precipitation method. The developed SnO2 NPs exhibit tetragonal structure with space group P42/mnm. Addition of dopants reduces the particle size from 23 nm (pure SnO2 NPs) to 18 and 16 nm (Mn- and Co-doped SnO2 NPs). The estimated band gap energy of pure, Co-, and Mn-doped SnO2 NPs were found to be 3.43, 2.70 and 2.84 eV, respectively. FTIR and EDX analyses also confirmed the incorporation of Mn and Co into the pure SnO2 NPs. Scanning electron micrograph revealed that the synthesized NPs were formed as large spherical shape by the aggregation of small individual nanoparticle. Photoluminescence spectrum of synthesized NPs shows the emission peaks in the visible region. Electrical properties of the proposed materials were studied from current (I) and voltage (V) characteristics. The results confirm the semiconducting behavior of the material and the I–V curves of all the samples reveal the nonlinear behavior of the synthesized materials.

Soft Chemical Fabrication and Material Characterization of Mn Doped SnO2 Ceramic Nanostructures for Application in Photocatalysis

In this research work, a simple soft chemical synthesis route is adopted to synthesize (Sn1-xMnxO2-δ; where x=0, 0.05,0.10, 0.15 and 0.20) based ceramic nanoparticles. The prepared nanoparticles were characterized to X-ray diffraction(XRD), FTIR spectroscopy, particle size analysis, SEM, EDAX, UV and photoluminescence (PL) studies. From XRD, thecrystalline geometry of ceramic nanoparticles was found to be tetragonal. FTIR data have shown a broad absorption band ata wavelength of ~ 600 cm-1 due to M-O stretching vibration mode. The ceramic nanoparticles were found to be in the rangeof 704 to 1258 nm. Smaller grains (<100 nm) along-with few bulky grains were reported by SEM. The absorption ofceramic particles was found maximum at 283 nm as per UV spectra. PL spectra exhibited a strong peak at 432 nm. Thephotocatalysis was studied to degrade methylene blue dye present in water sample using the ceramic nanoparticles underUV, visible and sun lights. Among the samples studied, Sn0.95Mn0.05O2-δ exhibited better photocatalytic degradation behavior(84.8%) under visible light after 120 minutes of irradiation.

Mn-doping-induced tunable bandgap and luminescence properties of SnO2 nanoparticles grown by SILAR method

In the present study, pure and Mn doped SnO2 thin films were grown by performing successive ionic layer adsorption and reaction (SILAR) method on the glass substrates at room temperature. The fabricated thin films have been studied to assess the influence of Mn doping on structural, morphological, and optical properties of SnO2 crystal lattice. The X-ray diffraction (XRD), Ultraviolet–visible spectrometer (UV–Vis), Energy dispersive X-ray analysis (EDAX), Scanning electron microscope (SEM), Raman, X-ray photoelectron spectroscopy (XPS), and Photoluminescence (PL) spectra measurements were conducted. After the XRD and SEM evaluations, it was found that the grown nanoparticles were in rutile type tetragonal structure of polycrystalline nature which was supported by Raman results. And, the surface morphologies were also observed to be affected from the varied concentrations of Mn doping. Besides, the EDAX evaluation confirmed the integration of Mn content next to Sn and O ions in the synthesized SnO2 nanostructures by SILAR method. The UVi-vis analysis disclosed that the absorbance of the prepared thin films had a clear inclination to increase as doping concentration intensified. In addition to that, the optical investigations also uncovered the bandgap of SnO2 nanocrystallines could be tuned from 2.61 eV to 2.00 eV by exposing them to the different levels of Mn ions. Furthermore, the Photoluminescence spectra evidently acknowledged the possibility of engineering optical characteristics by showing increased luminescent emission intensity values right after the introduction of impurities into the SnO2 lattice. The XPS results further verified the manganese and tin valences existed in the produced thin films.

Sunlight driven improved photocatalytic activity of Mn doped SnO2 nanowires

Sn1-xMnxO2 (x = 0, 0.1, 0.2 and 0.3) were successfully synthesized by simple Co-precipitation technique. The influence of Mn dopant on the crystal structure, surface morphology, optical, magnetic and electrical properties of SnO2 were investigated by various techniques like XRD, IR, TG/DSC, SEM, TEM, EDX, DRS, photoluminescence, magnetic susceptibility and electrical resistivity. XRD pattern reveal formation of tetragonal structure for undoped and Mn doped SnO2. SEM and TEM images of Mn doped SnO2 revealed formation of nanowires of different diameter and length. Mn substitution in SnO2 crystal lattice leads to widening of band gap and paramagnetic behavior. The photocatalytic activity was evaluated by the degradation of Naphthol Blue Black dye under solar light. Enhanced photocatalytic efficiency is exhibited by Sn0·7Mn0·3O2 within 180 min time. 92% reduction in COD value and presence of inorganic ions indicate complete mineralization of the NBB dye. Antibacterial activity of SnO2 towards gram positive and gram negative bacteria is also enhanced with Mn doping.

Morphological studies of p-type Mn-doped SnO2 nanostructure

SnO2 thin films doped with various manganese concentrations were prepared on glass substrates by sol–gel dip coating method. The decomposition procedure of com- pounds produced by alcoholysis reactions of tin and manganese chlorides was studied by thermogravimetric analysis (TGA). The effects of Mn doping on structural, morphological, electrical and optical properties of prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Hall effect measurement, Fourier Transform Infrared (FTIR) spectral analysis, UV–Vis spectrophotometry, and photo- luminescence (PL) spectroscopy. The results of the X-ray diffraction show that the samples are crystalline with a tetragonal rutile structure and the grain size decreases with increasing the doping concentration. The SEM and AFM images demonstrate that the surface morphology of the films was affected from the manganese incorporation. The Sn1−x Mnx O2 thin films exhibited electrically p-type behavior in doping level above x = 0.035 and electrical resistive increases with increase in Mn doping. The optical transmission spectra show a shift in the position of absorption edge towards higher wavelength (lower energy). The optical constants (refractive index and extinction coefficient) and the film thickness were determined by spectral transmittance and using a numerical approximation method. The oscillator and dispersion energies were calculated using the Wemple–DiDomenico dispersion model. The estimated optical band gap is found to decrease with higher manganese doping. The room-temperature PL measurements illustrate the decrease in intensity of the emission lines when content of Mn is increased in Mn-doped SnO2 thin films.

Enhanced sunlight photodegradation activity of methylene blue using Mn doped SnO2 loaded on corn cob activated carbon

In this work, Mn doped SnO2 loaded with a (0.5 ​g) corn cob activated carbon (Mn: SnO2/CCAC) are successfully synthesized by chemical precipitation method and its photocatalytic performance was estimated by photodegradation of methylene blue (MB) under sunlight irradiation. The materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (UV–Vis, DRS), photoluminescence (PL), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray analysis (EDAX), Brunauer-Emmett-Teller (BET) surface area and electrochemical impedance spectroscopy (EIS) analysis. The XRD results confirmed the rutile tetragonal crystalline structure and average crystalline size is decreased (13.79 ​nm) upon Mn doping and CCAC loading samples. The band gap value (Mn: SnO2/CCAC) is decreased (3.49 ​eV) compared to pure SnO2 and Mn doped SnO2 samples. Further, reduced PL emission intensity of Mn: SnO2/CCAC and its reduced value of impedance from EIS analysis and enhanced separation of the photogenerated electron-hole pairs, supports the enhanced photodegradation efficiency. As a result, the optimum Mn (0.10 ​M) doped SnO2/CCAC of the removal efficiency (97.76%) of MB dye reveals both improves photocatalysts (Mn-doped SnO2) and adsorption (CCAC) under sunlight within 120 ​min. The mechanism for the enhancement of photocatalytic activity under sunlight irradiation is also proposed.

Investigation of Magnetic and Optical Properties of Mn-Doped SnO&lt;sub&gt;2&lt;/sub&gt; at Different Annealing Temperatures

In this paper, a systematic investigation has been done to study the effect of variation in annealing temperature on magnetic and optical properties of Mn-doped SnO2. Co-precipitation technique has been used to synthesize Sn1-xMnxO2 samples with low Mn concentration (2 %). Pristine SnO2 is sintered at 350 oC. Mn-doped SnO2 samples are sintered at 350, 450, 550 and 650 oC. The structures of tetragonal rutile of SnO2 and Mn-doped SnO2 have been confirmed by the XRD pattern. Typical ferromagnetic ordering has been observed for Mn-doped SnO2 samples annealed at different temperatures. However, on increasing the annealing temperature saturation magnetization as well as the coercive field decreases, indicating a crucial phase transformation from ferromagnetism to paramagnetism. UV-Vis spectroscopy shows increase in absorbance and a slight shift in the absorption edge with Mn-doping at increasing annealing temperature indicating shifting of absorption peak towards higher wavelength. Tauc’s plot has been used to find the optical band gap (Eg).

Electronic structure and spontaneous magnetization in Mn-doped SnO2

Mn-doped SnO2 is a promising dilute magnetic semiconductor; however, there are many inconsistent reports on the magnetic ordering in the literature. We investigate the magnetic ordering and the local electronic structure in stoichiometric and Mn-doped (with Mn concentrations of 1 at.%, 3 at.%, and 6 at.%) SnO2 using magnetization measurements, Mn L2,3-edge and O K-edge x-ray absorption fine structure measurements, and density functional theory and model Hamiltonian calculations. We find that paramagnetic and ferromagnetic behavior is present as a function of Mn concentration and, in particular, that paramagnetic, ferromagnetic, and antiferromagnetic order coexist independently in Mn(6%):SnO2. Simultaneously, we find that Mn2+, Mn3+, and Mn4+ also coexist in Mn(6%):SnO2. These findings demonstrate the care needed to study Mn:SnO2 and point to the wealth of magnetic behaviors that might be realized with careful control of synthesis conditions.

Effect of the dopant on the structural and hyperfine parameters of Sn0.95M0.05O2 nanoparticles (M: V, Mn, Fe, Co)

In this work, we present a comparative study of the structural and hyperfine parameters on tin dioxide nanoparticles doped with different transition metal elements. The nanopowders with the stoichiometry Sn0.95M0.05O2 (M: V, Mn, Fe, Co) were synthesized by simple co-precipitation method. The characterization was carried out by conventional x-ray diffraction technique, transmission 119Sn Mössbauer spectroscopy and x-ray photoelectron spectroscopy (XPS). The effect of dopant element on structural parameters of tin dioxide and, particularly, on hyperfine parameters of Sn was analysed. It was found that dopants, except for Fe, were in two valence states. For the Mn-doped SnO2 sample, it was found the strongest influence of M cation on Sn hyperfine parameters, whereas Co-doped sample resulted in the least altered one as compared to doped and un-doped SnO2. We propose an explanation of the changes of the hyperfine parameters observed over the modification of the structural changes, based on the size of the dopant elements, whose oxidation states were identified by XPS. Additionally, it should not be discarded the relevant role of oxygen vacancies whose presence on the surface was indirectly witnessed by XPS.

Mn-doped atomic SnO2 layers for highly efficient CO2 electrochemical reduction

Ultrathin TMO has been synthesized via a facile in situ gas induced growth strategy and the structure–efficiency relationship has been deeply discussed.

Transition metal doped Sb@SnO2 nanoparticles for photochemical and electrochemical oxidation of cysteine

Transition metal-doped SnO2 nanoparticles (TM-SnO2) were synthesized by applying a thermos-synthesis method, which first involved doping SnO2 with Sb and then with transition metals (TM = Cr, Mn, Fe, or Co) of various concentrations to enhance a catalytic effect of SnO2. The doped particles were then analyzed by using various surface analysis techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning transmission X-ray microscopy (STXM), and high-resolution photoemission spectroscopy (HRPES). We evaluated the catalytic effects of these doped particles on the oxidation of L-cysteine (Cys) in aqueous solution by taking electrochemical measurements and on the photocatalytic oxidation of Cys by using HRPES under UV illumination. Through the spectral analysis, we found that the Cr- and Mn-doped SnO2 nanoparticles exhibit enhanced catalytic activities, which according to the various surface analyses were due to the effects of the sizes of the particles and electronegativity differences between the dopant metal and SnO2.

Surface Dielectric Tunnel Barrier Induced by Mn Doping in SnO2 Micro‐ and Nanostructures

Electrical properties of undoped and Mn doped SnO2 microplates and rods are studied by electron beam induced current (EBIC) in a scanning electron microscope (SEM), and I–V curves acquired at room temperature. AFM measurements reveal the formation of numerous terraces at the (−101) surface of the analyzed Mn‐doped SnO2 microplates, which also exhibit high carrier recombination processes at their central region, as confirmed by combined EBIC and cathodoluminescence (CL) measurements. A diffusion length for minority carriers about 205 nm is obtained by EBIC measurements. Different electrical conduction mechanisms, such as Fowler‐Nordheim, direct tunneling and Poole‐Frenkel, are evaluated in the electrical analysis of the samples. Mn doped microplates show lower conductivity than the undoped microds. Moreover the height of the surface tunnel barrier is increased by Mn doping, as confirmed by the analysis of the I–V curves acquired under transversal configuration. A value of the relative dielectric constant ϵr about 7.3 is estimated for the probed SnO2 microstructures.

Optical, dielectric and magnetic properties of Mn doped SnO2 diluted magnetic semiconductors

Nanocrystalline pure and doped Sn1-xMnxO2 (with x = 0, 0.01, 0.03, 0.05) samples were synthesized chemically using co-precipitation technique. The tetragonal phase of the synthesized powder samples was confirmed by X-Ray diffraction measurement. FTIR spectra were recorded to reveal the functional groups in as-synthesized powder samples. The average crystallite size was calculated by Debye-Scherrer formula and found to be in the range of 21.8–32.2 nm. The optical band gap is found in the range 3.80–3.91 eV due to small redshift in UV–Vis absorption spectra. Photoluminescence spectra reveal the presence of the defects like oxygen vacancies in the materials. The dielectric properties such that dielectric constant, dielectric loss and ac conductivity with frequency have been studied in the frequency range of 42–5 MHz. Impedance spectroscopy was used to study the behavior of grains and grain boundaries parameters. The ferromagnetic behavior of pure and Mn doped SnO2 diluted magnetic semiconductor have also been discussed in detail.