Stannous Research Articles

Characterization and electrochemical performance of plasma-nitrided titanium alloy for bipolar plates

Ti-N layer with a thickness about 1 ∼ 2.2 μm was formed on titanium alloys through plasma nitriding at 750 °C in NH3 and a mixture of NH3 and N2 (1:2) for 4 h. SEM and XRD were employed to characterize the microstructure and phase composition of nitrided layer. Electrochemical tests evaluated the anti-corrosion properties of the samples before and after nitrided in a simulated proton exchange membrane fuel cells (PEMFC) environment. Interface contact resistance (ICR) was also measured. Results indicated that the corrosion potential in cathodic conditions was increased from −415 mV for untreated titanium to 148 mV for that nitrided in mixture gas. While, the corrosion current density was reduced from 6.64 μA to 0.86 μA. Under a pressure of 140 N cm−2, the interfacial contact resistance of the untreated sample increased from 22.1 mΩ cm2 before corrosion testing to 40.5 mΩ cm2 after corrosion at cathodic conditions. The nitrided sample, on the other hand, saw its contact resistance rise from 4.5 mΩ cm2 before corrosion to 7.3 mΩ cm2 after corrosion. The Ti-N compound layer effectively diminished the corrosion current density and sustained an exceptionally low ICR under the simulated operating conditions of a bipolar plate.

SnF(bipy)(H2O)]2[SnF6], a mixed-valent inorganic tin(II)-tin(IV) compound.

In the title compound, bis-[aqua-(2,2'-bi-pyridine)-fluorido-tin(II)] hexa-fluorido-tin(IV), [SnF(C10H8N2)(H2O)]2[SnF6], an ionic mixed-valent tin(II)-tin(IV) compound, the bivalent tin atom is the center atom of the cation and the tetra-valent tin atom is the center atom of the anion. With respect to the first coordination sphere, the cation is monomeric, with the tin(II) atom having a fourfold seesaw coordination with a fluorine atom in an equatorial position, a water mol-ecule in an axial position and the two nitro-gen atoms of the chelating 2,2'-bi-pyridine ligand in the remaining axial and equatorial positions. The bond lengths and angles of this hypervalent first coordination sphere are described by 2c-2e and 3c-4e bonds, respectively, all of which are based on the orthogonal 5p orbitals of the tin atom. In the second coordination sphere, which is based on an additional, very long tin-fluorine bond that leads to dimerization of the cation, the tin atom is trapezoidal-pyramidally coordinated. The tetra-valent tin atom of the centrosymmetric anion has an octa-hedral coordination. The differences in its tin-fluorine bond lengths are attributed to hydrogen bonding, as the two of the four fluorine atoms are each involved in two hydrogen bonds, linking anions and cations together to form strands.

Preparation of TiN compound layer by intermittent vacuum diffusion nitriding on Ti6Al4V titanium alloy

An intermittent vacuum diffusion nitriding (IVDN) treatment was used for the preparation of a TiN compound layer on the surface of the Ti6Al4V titanium alloy. The underlying microstructure evolution and the properties were thoroughly investigated. The IVDN process was performed alternately by using intermittent nitriding and vacuum diffusion. The TiN compound layer was formed on the surface discontinuously, layer by layer. As a result, the TiN compound layer was formed easily on the surface of titanium alloy compared to the vacuum nitriding. Dislocations were also generated in the adjacent α-Ti grains of the TiN compound layer. Interestingly, the induced dislocation defects possessed high free energy and contributed to the generation of the TiN grain nucleus, which facilitated the diffusion of the N atoms towards the inner substrate. The acquired results disclosed the intrinsic reason for the diffusion behaviour of N atoms. The Ti6Al4V titanium alloy was nitrided by using IVDN treatment at the temperature of 700 °C for 10 h. The surface microhardness reached 900–950 HV and presented continuous gradient change. In addition, the IVDN sample exhibited enhanced wear resistance properties than the un-nitrided sample.

Effect of Sn content on microstructure and mechanical properties of Mg-2Zn-1Ca-xSn /Al composite plate

This article explores the effects of different amounts of Sn (1,2,5 wt%) added to magnesium matrix on the microstructure and formability of Mg-2Zn-1Ca-xSn/Al composite plates. The second phase analysis results indicate that Sn element has a significant inhibitory effect on Ca2Mg6Zn3 phase. As the Sn element increases, the Ca2Mg6Zn3 phase gradually disappears, but the number and size of CaMgSn phase increase significantly (5–8μm). The tensile results at room temperature indicate that the composite plate has the highest strength but lower elongation when the Sn content is 2 wt%. It is mainly attributed to the dispersed distribution of small-sized second phases (<1μm), which cause pinning effect on dislocations and lead to dislocation accumulation. Excessive Sn (5 wt%) can promote dynamic recrystallization, resulting in equiaaxial grain distribution. The average Schmidt factor (0.22) of the basal slip is concurrently increased, makes the base slip system easier to start at room temperature. The Mg-2Zn-1Ca-5Sn alloy exhibits obvious softening, leading to a significant reduction in hardness difference between the Mg-2Zn-1Ca-5Sn alloy and the Al alloy. The enhanced feature also facilitates improved coordinated deformation capability and serves to prolong the occurrence of interface delamination in deformation. The Mg/Al composite plate exhibits excellent plastic deformation ability when the Sn content is 5 wt%, the average performance values were 207.52 MPa (UTS), 145.48 MPa (YS) and 17.45 %(EL), respectively. The fracture behavior of the composite plate undergoes a shift from brittle fracture to a combination of ductile and brittle fracture modes, occurring simultaneously. In summary, the incorporation of an optimal amount of Sn content can enhance the plastic formability of Mg/Al composite plates.

Development of organic photoreactions utilizing the characteristics of elements with low electronegativity

Abstract Organic photoreactions have received much attention as unique tools to access kinetically and/or thermodynamically prohibited products in the ground state. These photoreactions have been based mainly on using elements with high electronegativity such as carbon (C), oxygen (O), nitrogen (N), halogens (F, Cl, Br, and I) as well as transition metals. On the other hand, we have been interested in the characteristics of elements with low electronegativity, such as boron (B), silicon (Si), and tin (Sn), in the excited state, enabling highly reactive and/or selective photoinduced borylations, silylations, and stannylations. In this account, we highlight our latest findings concerning diverse organic photoreactions utilizing B, Si, and Sn elements, which are challenging when using conventional strategies.

Circular Economy Principles in the Regulatory Oversight of the Management of By- Products – Case Study: Tin Slag 2

The tin processing industry generates abundant slag, as a by-product, that contains radioactive substances from uranium and thorium decay series radionuclides. The increase in tin production will be proportional to the rise in tin slag. The Circular economy is a concept that aims to minimize the extraction of primary resources, keep resources as long as possible, increase added value, or limit the final disposal of waste. The concept of reuse, recycling, or reprocessing is part of the concept. This paper aims to identify aspects of the existing regulations in Indonesia that support circular economy principles in the management of by-products, such as tin slag 2. The methodology used in this paper is a literature study of regulations, international recommendations, and related research. Based on the measurements of tin slag 2 samples originating from Bangka Belitung Province, the main chemical constituents based on XRF analysis are SiO2, CaO, MgO, Fe2O3, and TiO2. The activity concentration of a tin slag 2 sample showed a value that exceeded the criterion of 1 Bq/gram for the radionuclides in the uranium and thorium decay series. From a material perspective, tin slag 2 can be reused or recycled for specific purposes. Various studies have proven the performance of tin slag 2 as a partial substitution of fine aggregate or cement in manufacturing mortar or concrete. The identification shows that several existing regulations in Indonesia explicitly and implicitly regulate the provisions of the circular economy concept. According to the Ministry of Environment and Forestry regulations, by-products with activity concentrations of less than 1 Bq/gram can be used as raw material, raw material substitution, energy source substitution, and other uses. Meanwhile, the by-products with activity concentrations of more than 1 Bq/gram are challenging as the provisions of by-products with a value of more than 1 Bq/gram are regulated in BAPETEN Regulation No. 16 of 2013 (currently in the revision stage). BAPETEN Regulation No. 16 of 2013 explains that by-products can be utilized for certain activities. However, the regulation must explain the terms and criteria for reusing by-products. Provisions of by-product processing, as stipulated in GR No. 52 of 2022, are limited to extracting nuclear minerals such as uranium and thorium. So, the meaning of processing in GR No. 52 of 2022 and provisions for reuse previously contained in BAPETEN Regulation No. 16 of 2013 have different meanings. Keywords: circular economy, by-product, tin, slag 2, radioactive substances, nuclear minerals

Editorial for Special Issue “Rare Metal Ore Formations and Rare Metal Metallogeny”

Rare metals (usually defined as including elements such as Li, Rb, Cs, Be, Sn, Nb, Ta, Zr, Y, U, and rare-earth elements) are included in the list of “critical mineral resources” by major economies around the world [...]

Qalaee (Stannum) metallic origin element, its chemical compounds, action, therapeutic uses, adverse effect and pharmacological activity studies: A Review

Qalaee is Unani name of tin (stannum), which is a metallic element, belongs to group 14 of periodic table. Atomic number of tin is 50 and its atomic mass is 119. Qalaee (Tin) consist two types of compounds, inorganic tin compounds and organic tin compounds. Several toxic and adverse effect studies of Qalaee (stannum) have been reported such as, Respiratory Effects, Gastrointestinal Effects, Haematological Effects, Renal Effects, Dermal Effects, Ocular Effects, Immunological and Lymph reticular Effects, Neurological Effects, Cardiovascular Effects, Body weight effect and reproductive effects. Some studies on different pharmacological activities of tin also reported like, antibacterial activity, anticancer activity and anti-parasitic activity. In traditional system of medicine Qalaee is used in the form of Kusta or Bhasm for various disorders such as spermatorrhoea, excessive nocturnal emission, premature ejaculation and Syphilis etc. Its important Unani formulation is Kusta qalaee. Keyword: Qalaee (Stannum), Action and Therapeutic use, adverse effect, Pharmacological action

Microstructure evolution and mechanical properties of Cu–9Ni–6Sn alloy during continuous cold deformation process

A Cu–9Ni–6Sn alloy bar with pronounced axial columnar grains and a diameter of 10.5 mm was fabricated by using directional solidification technology, which was directly cold-drawn into a superfine alloy wire with a diameter of 40 μm without intermediate annealing. The strength and microstructure evolutions of the Cu–9Ni–6Sn alloy during the cold drawing were studied. The results indicate that twinning is more likely to occur in fiber structures ranging from 60 to 120 nm. A dual-fiber structure consisting of <111> and <100> orientations formed after cold-drawing. Unexpectedly, a large number of deformation twins were discovered within the <111> fibrous texture and later transformed into detwinning structures, disrupting the axial fibrous texture. The generation of deformation twinning primarily results from Ni and Sn elements disrupting crystal symmetry and reducing stacking fault energy of the alloy and the formation of <111> texture. The combined effects of detwinning structures and dislocation wall induced work-softening of the alloy, enabling high-strain processing and ultimately yielding nanocrystalline grains, i.e., the Cu–9Ni–6Sn alloy underwent cold drawing with a high train of 11.23 and obtained an average grain size of ∼38 nm, which exhibited a tensile strength of 1453 MPa.

Microscopic damage in eutectic SnPb alloy: First-principles calculations and experiments

This study aims to comprehensively elucidate the microscopic origins of damage in eutectic SnPb alloy through atomic-scale investigations, a crucial endeavor for enhancing the alloy’s properties and furthering the development of Pb-free solders. First-principles calculations based on density functional theory (DFT) were employed to examine the mechanical constants and defect formation energies of the Pb phase, the β-Sn phase, and potential Sn/Pb eutectic phases in the SnPb alloy. The Voigt-Reuss-Hill approximation was utilized to derive the mechanical parameters of the elastically stable structure in SnPb alloy, facilitating the prediction of its mechanical properties. The defect formation energy calculations revealed a higher difficulty in forming vacancy defects in the β-Sn phase compared to the Pb phase. This discrepancy can be attributed to the stronger interactions between Sn atoms, resulting in the formation of more stable Sn-Sn bonds, thereby impeding vacancy generation in the β-Sn phase. Furthermore, the Pb phase exhibited a tendency for Sn atoms to occupy octahedral interstitial sites, whereas in the β-Sn phase, Pb atoms tended to displace neighboring Sn atoms along the [110] orientation into adjacent interstitial sites and occupy their lattice positions. Experimental observations complemented these calculation findings, demonstrating significant Sn element presence, up to 27.22 at%, in the Pb-rich phase, with notable microvoid damage primarily concentrated within this region. This observation aligns with the conclusions drawn from first-principles calculations and unveils the microscopic origins of damage in eutectic SnPb alloys.

A comprehensive investigation of alloying elements on site preferences, elastic properties and electronic structure of Mg17Al12 by first-principles calculations

The effect of elemental doping on the site preference, elastic properties and electronic structure of Mg17Al12 has been systematically investigated by first-principles calculations. And twenty-seven elements (Li, Na, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Y, Zr, Ag, Cd, In, Sn, Sb, Pb, Bi and La) are considered in this study. The calculations of substitution formation energies indicate that the alkali metal (Li), alkaline earth (Ca, Sr) and rare earth (Sc, Y, La) group elements and Ti, Zr favor to occupy Mg sites, and transition group (Fe, Co, Ni, Cu, Ag, Zn, Cd) elements and Ga, Ge, Sn, Sb prefer to occupy Al site, while Na, K, V, Cr, Mn, In, Pb and Bi are unstable in Mg17Al12 phase. Meanwhile, the results of phonon dispersion curves for the preferentially doped systems show that all doped structures are dynamically stable except for Sr, La and Sn doped systems. The elastic constants indicate that all preferential doping models are mechanically stable, and solute atoms with high bulk modulus lead to an increase in the bulk modulus of Mg17Al12 phase. Simultaneously, the calculated shear modulus/bulk modulus ratio (G/B), Poisson's ratio (v) and Cauchy's pressure (C‾12‐C‾44) indicate that the ductility of doped systems is better than Mg17Al12 alloy. All structures are elastic anisotropic, while the doping of Fe, Co and Ni reduces the degree of anisotropy of Mg17Al12 phase. Furthermore, the electronic structures show a strong hybridization between the p-orbitals of Mg and Al and the d-orbitals of alkaline earth, rare earth and Zr elements, resulting in higher structural stability. Finally, the adsorption behavior of O atom on Mg17Al12(110) surface and the structural stability, lattice constants, and elastic modulus of Mg34Al24-xZnx random solid solution alloys are investigated.

Biosynthesis of Tin(IV) Oxide Nanoparticles (SnO2 NPs) via Chromolaena Odorata Leaves: The Influence of Heat on the Extraction Procedure

In this study, the biosynthesis of tin(iv) oxide nanoparticles (SnO2 NPs) using leaves extract of Chromolaena Odorata was described. Although the traditional extraction method typically requires heating for collecting the extract, this study performed the extraction utilizing free heat. Subsequently, a comparative analysis was performed with the boiled version to recognize any distinctions in the formation of SnO2 NPs. Leaves of C. odorata contains bioactive compounds, particularly polyphenolic flavonoids which potentially serve as effective agents in green synthesis, acting as both reducing and capping agents for Sn4+. The synthesis was conducted at ambient temperature, followed by calcination at 700°C. FESEM images revealed that the morphologies of SnO2 NPs in both samples were uniform and spherical. The presence of O and Sn elements was further confirmed by EDX analysis, with atomic composition of approximately 76% and 23%, respectively. XRD obtained the most prominent peaks of SnO2 NPs which are (110), (101) and (211) in fair sharpness for both samples, with tetragonal structure. Furthermore, the FTIR spectrum affirmed the presence of pertinent functional groups through the vibration and stretching pattern of SnO2 and Sn-OH groups. Based on these findings, the heat-free treatment of C. odorata extract proves to be comparable to the boiled version in mediating biosynthesis. Nevertheless, the preference is towards the traditional process, as the use of heat enhances the extraction process by increasing the abundance of bioactive compounds without undergoing degradation. Additionally, it aids in stabilizing the structure of SnO2 NPs and preventing agglomeration.

Elemental Analysis of Onobrychis buhseana Bunge Ex Boiss and Onobrychis bobrovi Grossh Species by ICP-MS

The element composition of the underground and surface parts of Onobrychis buhseana and Onobrychis bobrovi, which are distributed in the flora of Azerbaijan, was studied by an ICP-MS device, and the amount of 26 elements (Li, Be, B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Ag, Cd, Sn, Ba, Ce, Tl, and Pb) in the raw material was determined in ppm. The composition of raw materials is dominated by some macroelements (calcium, potassium, and magnesium), microelements (iron and zinc), and ultramicroelements (selenium, cobalt, and chromium). Some of the most frequent harmful trace elements, such as As and Cd, were discovered at extremely low concentrations.

Discrimination of Pb-Zn deposit types using the trace element data of galena based on deep learning

Different types of ore deposits exhibit distinct metal sources, physicochemical conditions, and ore-forming processes. Galena, a key sulfide in Pb-Zn deposits, possesses trace elements that may be utilized for classifying Pb-Zn deposit types. Presently, research on classifying ore deposit types based on trace elements in galena is sparse, and there is a lack of robust methods for distinguishing Pb-Zn deposit types using these trace elements. In this study, we demonstrate that a deep learning algorithm, based on the trace elements in galena, can be effectively utilized for classifying Pb-Zn deposit types. The model training process utilized UMAP for visualization, and the evaluation was conducted using multiple statistical metrics, confusion matrices, and ROC curves. Finally, by dissecting the ’black box’ with the UMAP algorithm, we established a comprehensive set of analysis methods for discriminating deposit types: discrimination-visualization-evaluation-dissection. A dataset comprising 828 LA-ICP-MS analyses of galena from 34 Pb-Zn deposits worldwide was curated from peer-reviewed sources. It includes data on 7 elements (Se, Ag, Cd, Sn, Sb, Tl, and Bi) across 7 deposit types: carbonate replacement deposits (CRD), epithermal, mississippi valley type (MVT), sedimentary exhalative (SEDEX), skarn, volcanogenic massive sulfide (VMS), and vein-type deposits. Initially, we selected the UMAP algorithm from three visualization methods (PCA, t-SNE and UMAP), for its ability to balance global and local structures in visualizing the internals of the deep model. Subsequently, we developed a deep learning model (1D-CNN) for deposit type classification. Various evaluation metrics and visual analyses indicate exceptional performance of our model, achieving an overall accuracy of 99.18 % on the test set. Finally, the SHAP algorithm was used to analyze the importance of trace elements in galena for different deposit types. Elements such as Sn, Tl, and Bi were found to be particularly significant in classifying deposit types, confirming the influence of multiple elements in Pb-Zn deposits within galena. Therefore, we conclude that deep learning algorithms can effectively identify Pb-Zn deposit types, offering new insights into the study of galena.

Perovskite nanowire-based electrochemical sensing for selective and rapid detection of hydrogen peroxide

Nanowires possess inherent advantages in improving the reduction of boundary stacking defects and enhancing charge transfer or migration. Here, we synthesized all-inorganic perovskite nanowires CsPbBr3 (PVSK NW) and obtained CsPb1-xSnxBr3 (PVSK-Sn NW) and CsPb1-xGexBr3 (PVSK-Ge NW) nanowires through doping with different elements (Sn and Ge). Elemental doping endows the nanowires with unique narrow fluorescence spectra, high optical absorption coefficients, tunable optical bandgaps, and high carrier mobility. Introducing different perovskite nanowires into carbon-based composite materials (super p/Nafion) can overcome the challenges of hydrogen peroxide (H2O2) detection sensitivity and matrix interference. H2O2 in PBS (phosphate buffered saline) solution (pH 7.0) was detected by current analysis i-t curve mode. The results demonstrate that the addition of perovskite nanowires exhibits a high level of detection sensitivity for H2O2 electrochemical reduction. Particularly, the linear concentration range detected by PVSK-Sn NW is 1–6000 µM, with a detection limit of 0.12 µM. Even in the presence of interfering molecules (ascorbic acid, uric acid, glucose), the detection of H2O2 maintains high sensitivity and selectivity. This study overcomes the limitations of perovskite materials in water-based detection, enhancing their future commercial applications as sensing devices.

INVESTIGATION OF SILVER FORGERIES OF ANCIENT COINS: CASE STUDY OF SILVER COINS OF PARTHIA (ORODES II AND PHRAATES VI)

The investigation into the elemental composition and microstructural characteristics of ancient coins gives valuable information to researchers which greatly aid in the detection of counterfeits. This research aim is analysis encompasses an examination of major and trace elements present in the coins of Parthia, to identify forgery techniques utilizing the PIXE technique. The results show the elements Cl, Ca, Fe, Cu, Ag, Au, Pb, Sn, and Zn were identified and according to the ratio Ag/ Cu, can be said that the Parthia period occasionally used forged silver-plated coins. The elemental composition of silver coins of Orodes II and Phraates IV observes these coins are made with plating silver and affixed to the core utilizing a silver-copper eutectic layer, while the core itself consists of copper, and quantities of tin (Sn) were detected which may have been intentionally added for metallurgical, political, or historical reasons.

Electrochemical performance of Fe-doped SnSe material electrodes for supercapacitors

This paper synthesized Fe-doped SnSe nanoparticles (NPs) through the co-precipitation technique. The X-ray diffraction (XRD) confirms the orthorhombic crystal structure of Fe-doped SnSe NPs. The chemical states of Sn, Fe and Se elements were identified by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDAX). The galvanostatic charge-discharge (GCD) was used to measure the power efficiency of Fe-doped SnSe electrodes. The specific capacitance of 1283 F/g at a current density of 5 A/g was obtained using a three-electrode system. Further, the Fe-doped SnSe electrode shows a specific energy (Es) of 64 Whkg−1 at a specific power (Ps) of 1500 Wkg−1, respectively. The Fe-doped SnSe electrode exhibits a capacitance retention of 101 % for 1000 GCD cycles in a two-electrode system. This study confirms that the Fe-doped SnSe electrodes are the substitute and life-lasting electrodes for supercapacitor devices.

Effects of Low-Temperature Heat Treatment on Mechanical and Thermophysical Properties of Cu-10Sn Alloys Fabricated by Laser Powder Bed Fusion.

This study investigated the impact of low-temperature heat treatments on the mechanical and thermophysical properties of Cu-10Sn alloys fabricated by a laser powder bed fusion (LPBF) additive manufacturing (AM) process. The microstructure, phase structure, and mechanical and thermal properties of the LPBF Cu-10Sn samples were comparatively investigated under both the as-fabricated (AF) condition and after low-temperature heat treatments at 140, 180, 220, 260, and 300 °C. The results showed that the low-temperature heat treatments did not significantly affect the phase and grain structures of the Cu-10Sn alloys. Both pre- and post-treatment samples displayed consistent grain sizes, with no obvious X-ray diffraction angle shift for the α phase, indicating that atom diffusion of the Sn element is beyond the detection resolution of X-ray diffractometers (XRD). However, the 180 °C heat-treated sample exhibited the highest hardness, while the AF samples had the lowest hardness, which was most likely due to the generation of precipitates according to thermodynamics modeling. Heat-treated samples also displayed higher thermal diffusivity values than their AF counterpart. The AF sample had the longest lifetime of ~0.19 nanoseconds (ns) in the positron annihilation lifetime spectroscopy (PALS) test, indicating the presence of the most atomic-level defects.

Quantification of regulated metals in recycled post-consumer polypropylene through comparative ICP-MS, AAS and LIBS analyses

Knowing the exact heavy metal load of recycled plastics is important for their risk assessment. We therefore established a novel strategic hierarchy for testing the heavy metal load of recycled plastics. For preliminary screening for unusually high elemental loads, laser-induced breakdown spectroscopy (LIBS) is suggested, while inductively coupled plasma-mass spectrometry (ICP-MS) or electrothermal atomic absorption spectroscopy (ETAAS) are used for exact quantification. The contents of ten regulated elements (Hg, As, Cd, Cr, Co, Cu, Se, Pb, Sn and Ni) in post-consumer (PCR), post-industrial (PIR), and virgin polypropylene (PP) were thus determined. Concentrations in the PCR were mostly found to be two orders of magnitude smaller than their threshold in non-food applications. Cu was most abundant in PCR with 18.7 ± 6.1 mg/kg. Concentration variations of approx. 30 %. were found within a PCR batch, while between batches, slightly higher variations of 30–40 % were observed. Moreover, the heavy metal concentration patterns of PCR and PIR differ significantly. This strategy may enhance the applicational possibilities for PCR.

Enhanced optoelectronic and catalytic properties of Sm doped SnO2 thin films

Herein, we report the optoelectronic and malachite green (MG) aqueous dye model pollutant degradation characteristics of samarium (Sm) doped tin oxide (SnO2:Sm) thin films deposited on glass substrate by chemical spray pyrolysis technique. The tetragonal crystal structure and polycrystalline nature were elucidated from X-ray diffraction (XRD) analysis, and the calculated crystallite size using Scherrer's relation was found to vary between 36 and 45 nm. A high optical transparency of 92 % was achieved for SnO2:Sm (3 wt%). The extrapolation of linear fit indicates a slight decrement in the band gap. Energy dispersive X-ray analysis (EDAX) confirmed the presence of Sn, O and Sm elements and their composition. The quantitative compositional percentage of Sn, O and Sm was determined by X-ray photoelectron spectroscopy (XPS) analysis. The scanning electron micrographs (SEM) showed polyhedron-like shaped grains with cracks and void-free film surface. The 3 wt% Sm:SnO2 thin film exhibited a higher average surface roughness (19.63 nm) than other films. Strong ultraviolet (365 nm), blue (493 nm), and green (520 nm) emissions were observed for all the films, as recorded by photoluminescence (PL) studies. High electron concentration (7.9 × 1020/cm3), low resistivity (0.356 × 10−3 Ω cm), and a high figure of merit (FOM, 5.11 × 10−2 Ω−1) were obtained for 3 wt % of SnO2:Sm thin films. Furthermore, a relatively high photocurrent (8.22 mA) was attained for the 3 wt% Sm:SnO2 thin film. Enhanced photocatalytic efficiency (95 %) was achieved for the 4 wt% Sm:SnO2 film against MG dye aqueous solution. The results obtained in the present study demonstrate high optical transparency, electrical conductivity, enhanced FOM, and photocatalytic degradation efficiency for 3 and 4 wt% Sm-doping, respectively. Therefore, Sm-doped SnO2 could be useful for developing and designing novel devices for optoelectronic and photocatalytic applications.