Stability Of Sn Research Articles

Tautomeric mixture coordination enables efficient lead-free perovskite LEDs.

Lead halide perovskite light-emitting diodes (PeLEDs) have demonstrated remarkable optoelectronic performance1-3. However, there arepotential toxicity issues with lead4,5 and removing lead from the best-performing PeLEDs-without compromising their high external quantum efficiencies-remains a challenge. Here we report a tautomeric-mixture-coordination-induced electron localization strategy to stabilize thelead-free tinperovskiteTEA2SnI4 (TEAI is2-thiopheneethylammonium iodide) by incorporating cyanuric acid. We demonstrate that a crucial function of the coordination is to amplify theelectronic effects, even for those Sn atoms that aren't strongly bonded with cyanuric acidowing to the formation of hydrogen-bonded tautomeric dimer and trimer superstructures on the perovskite surface. This electron localization weakens adverse effects from Anderson localization and improves ordering in the crystal structure of TEA2SnI4. These factors result in a two-orders-of-magnitude reduction in thenon-radiative recombination capture coefficient and an approximately twofold enhancement inthe exciton binding energy. Our lead-free PeLED has an external quantum efficiency of up to 20.29%, representing a performance comparable to that of state-of-the-art lead-containing PeLEDs6-12. We anticipate that these findings will provide insights into the stabilization of Sn(II) perovskites and further the development of lead-free perovskite applications.

Correlation of X-Ray Diffraction, X-Ray Absorption Spectroscopy and Optical Properties of Europium Activated Spaniel Calcium Stannate

Ca2SnO4:xEu3+ phosphors were synthesized by solid-state reaction method and characterized systematically using by XRD, XANES, EXAFS and PL spectroscopy. The XRD, XANES and EXAFS confirmed the formation of the Ca2SnO4 and the stabilization of Sn and Eu ions in 4+ and 3+ oxidation states. The PL properties of theses phosphor were investigated at room temperature. The emission spectra represent reddish-orange performance, which is due to the 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transition of Eu ions. The red emission from transition 5D0 → 7F2 (red) is dominate over that of 5D0 → 7F1 (orange). The impact of doping Eu3+ and PL properties were investigated, and we propose a feasible interpretation, which this phosphor could be a good candidate as a reddish-orange component in the fabrication of white LEDs.

Achieving Bright Reddish-Orange Luminescence in CaSnO3 Ceramics through Doping Manipulation

The reddish-orange phosphors of rare-earth activator have attracted intense interest due to their applications in lighting and display devices, including plasma display panel, field emission display and white light diode. In this work, Eu-doped CaSnO3 phosphor materials were prepared and examined. Their X-ray diffraction patterns were used for lattice parameters calculations and show that there was no phase transformation in all doping conditions. XANES studies suggest the stabilization of Sn and Eu ions in 4+ and 3+ oxidation states in the prepared phosphors, respectively. A broad emission band, with a major peak at 614 nm upon excitation wavelength of 395 nm, was observed in the range of 550 to 730 nm at room temperature due to 5D0 → 7FJ transition of Eu3+ ions. The luminescent spectra of the samples showed the intense light emission in the red-orange light region.

Insights into Electrochemical Behavior, Phase Evolution and Stability of Sn upon K-alloying/de-alloying via In Situ Studies

We report here results based on electrochemical K-alloying/de-alloying and associated in-situ studies with Sn in K ‘half cells’. The as-recorded reversible K-capacity of ∼245 mAh/g agree with the ‘final’ phase (K4Sn4) observed in in-situ synchrotron XRD scans at the end of one K-alloying half cycle. The electrochemical cycling and in-situ XRD results indicate that K4Sn4 forms via one-step phase transformation with no prior Sn-K solid solution formation and reverts back to β-Sn after de-potassiation half cycle (leading to ∼85 ± 6% first cycle coulombic efficiency). Interestingly, no notable evidence for occurrence of irreversible surface reaction could be found during the 1st discharge. However, strong evidences for the same were recorded (at ∼1.3–1.4 V, against K/K+) after completion of one full K-alloying/de-alloying cycle. In-situ monitoring of stress developments in the Sn film electrodes during galvanostatic cycling indicated the occurrence of mechanical instability not only during K-alloying/de-alloying induced phase transformations, but also upon occurrence of the surface reactions (as supported by SEM observations), which also lead to development of compressive stresses by itself. Accordingly, galvanostatic cycling within restricted cell voltage window of 1.2–0.01 V, as against 2–0.01 V, suppressed the irreversible surface phenomena and improved the cyclic stability.

Density Functional Theory Calculations of Atomic Configurations and Bandgaps of C-, Ge-, and Sn-Doped Si Crystals for Solar Cells

Poly-Si crystals are mainly used in solar cells because of their low cost. Here, the zones of sensitivity to wavelengths in sunlight should be expanded to increase the engineering efficiency of solar cells. Group IV compound semiconductors films, e.g., Si (Ge) films doped with C, Ge (C, Si), and/or Sn atoms with contents of several %, on a Si or Ge substrate have been identified as potential solutions to this technical problem. In this study, we calculated the formation energy of each atomic configuration of C, Ge, and Sn atoms in Si by using density functional theory. The “Hakoniwa” method proposed by Kamiyama et al. [Materials Science in Semiconductor Processing, 43, 209 (2016)] was applied to a 64-atom supercell of Si including up to three atoms of C, Ge, and/or Sn (up to 4.56%) in order to obtain the ratio of each atomic configuration and the average value of the Si bandgaps. Not only the conventional generalized gradient approximation (GGA) but also the screened-exchange local-density approximation (sX-LDA) functional was used to obtain more reliable Si bandgaps. The results of the analysis are fourfold. First, two C (Sn) atoms are energetically stable when they are 3rd, 4th, 6th, 7th, and 9th neighbors of each other, while the stability of two Ge atoms is independent of the atomic configuration. Second, C and Ge (Sn) atoms are stable when they are 2nd, 5th, and 8th (1st and 8th) neighbors, while the stability of Sn and Ge atoms is independent of the atomic configuration. Third, the Si bandgap depends (does not depend) on the atomic configuration when Si includes C and/or Sn atoms (Ge atoms). Uniformly mono-doping C by up to 4.68% and Ge (Sn) by up to 3.12% decreased the average value of the Si bandgaps. C doping decreased the Si bandgap the most, while Ge doping decreased it the least. Fourth, uniformly co-doping C and Sn in a 1:1 ratio (C and Ge 1:1, Ge and Sn 1:1) at 1.56% also decreased the Si bandgap. The results shown here will be useful for predicting the bandgap for a given content of Si crystals, which is important for the solar cell application.

The synthesis of ordered Sn–C composite microspheres and their mechanical properties

Abstract A method for the fabrication of carbon–tethered Sn micro/nano composite spheres, a facile one-pot hydrothermal route followed by heat treatment in N2, is described. Heating of an aqueous solution of SnCl4 and resorcinol–formaldehyde (RF) to 85 °C for about 3 h in a 50 mL Teflon-lined stainless steel autoclave obtained the SnO2 encapsulated RF composite polymer spheres. Subsequent heat-treatment at 800 °C for 2 h under N2 atmosphere, the RF polymer was carbonized to spherical carbon spheres, whereas SnO2 reduced into nanosized Sn metal that was melted, migrated, and then deposited outside the carbon surface. Variation of the concentration of the two jointly dissolved chemicals and heat treatment temperature enables a variation of the size of the Sn particles. The ordered carbon–tethered Sn composite spheres were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetrical analysis, and mechanical stable process measurements by ultrasonic oscillations. The mechanical stability of Sn–C is strong enough for ultrasonic oscillations for 30 and 60 min.

Improvement of the sodiation/de-sodiation stability of Sn(C) by electrochemically inactive Na2Se

The cycling stability of similarly made Sn : C electrodes improves when Se, present as non-cycling Na2Se, is added.

Ionic conductivity of Mn2+ doped dense tin pyrophosphate electrolytes synthesized by a new co-precipitation method

Mn 2+ -doped Sn 1− x Mn x P 2 O 7 ( x = 0–0.2) are synthesized by a new co-precipitation method using tin(II)oxalate as tin(IV) precursor, which gives pure tin pyrophosphate at 300 °C, as all the reaction by-products are vaporizable at <150 °C. The dopant Mn 2+ acts as a sintering aid and leads to dense Sn 1− x Mn x P 2 O 7 samples on sintering at 1100 °C. Though conductivity of Sn 1− x Mn x P 2 O 7 samples in the ambient atmosphere is 10 −9 –10 −6 S cm −1 in 300–550 °C range, it increases significantly in humidified (water vapor pressure, p H 2 O = 0.12 atm) atmosphere and reaches >10 −3 S cm −1 in 100–200 °C range. The maximum conductivity is shown by Sn 0.88 Mn 0.12 P 2 O 7 with 9.79 × 10 −6 S cm −1 at 550 °C in ambient air and 2.29 × 10 −3 S cm −1 at 190 °C in humidified air. It is observed that the humidification of Sn 1− x Mn x P 2 O 7 samples is a slow process and its rate increases at higher temperature. The stability of Sn 1− x Mn x P 2 O 7 samples is analyzed.

Investigation of drug delivery on anticancer drug by SWCNT with theoretical studies

The interaction of anticancer drug Sn(CH3)2(N-acetyl-L-cysteinate), that is called (N-acetyl-L-cysteinato-O,S) dimethyl tin(IV), with single walled carbon nanotube (SWCNT) is investigated by Quantum chemical ab initio calculations at HF/(LanL2DZ+STO-3G) and HF/(LanL2DZ+6-31G) levels in gas phase and solution. The solvent effect is taken into account via the self-consistent reaction field (SCRF) method. Carbon nanotubes can act as a suitable drug delivery vehicle for internalization, transportation and translocation of Sn(CH3)2(N-acetyl-L-cysteinate) within biological systems. Thermodynamical analysis indicates that the relative energies (ΔE), enthalpies (ΔH) and free Gibbs energies (ΔG) are negative for Sn(CH3)2(N-acetyl-L-cysteinate)-CNT system, but the calculated entropies (ΔS) are positive, suggesting thermodynamic favorability for covalent attachment of Sn(CH3)2(N-acetyl-L-cysteinate) into carbon nanotube. Also, the results show that with increasing dielectric constant of solvent, the stability of Sn(CH3)2(N-acetyl-L-cysteinate)-CNT complex decreases. Furthermore, anisotropic chemical shift tensor (Δσ), total atomic charge and asymmetry parameter (η) have been calculated using the gauge-including atomic orbital (GIAO) method, results being compared with CGST data. From the nuclear magnetic resonance (NMR) calculations, it can be seen that the NMR (Δσ, η) parameters at the sites of nitrogen and oxygen, as well as C-2 and C-3 nuclei are significantly influenced by intermolecular hydrogen-bonding interactions, but the quantity at the site of S-27 is influenced by nonspecific solute-solvent interaction, such as polarisability/polarity. Key words: Sn(CH3)2(N-acetyl-L-cysteinate), nuclear magnetic resonance (NMR) parameters, single walled nanotube (SWNT), solvent.

First-principle study of electronic structure and stability of Sn 0.5Sb 0.5O 2

A theoretical study on Sb-doped SnO 2 has been carried out by means of periodic density functional theory (DFT) at generalized gradient approximation (GGA) level. Stability and conductivity analyses were performed based on the formation energy and electronic structures. The results show that Sn 0.5Sb 0.5O 2 solid solution is stable because the formation energy of Sn 0.5Sb 0.5O 2 is −0.06 eV. The calculated energy band structure and density of states showed that the band gap of SnO 2 narrowed due to the presence of the Sb impurity energy levels in the bottom of the conduction band, namely there is Sb 5s distribution of electronic states from the Fermi level to the bottom of conduction band after the doping of antimony. The studies provide a theoretical basis to the development and application of Sn 1− x Sb x O 2 solid solution electrode.

Structural, electronic and optical properties of Sn1−xSbxO2

The goal of this paper is to undertake a detailed first principle calculation of the structural, electronic and optical properties of Sn 1− x Sb x O 2 . The results show that the stability of Sn 1− x Sb x O 2 in the full range of Sb content points to the probability of a continuous solid solution, where the increasing Sb content leads to volume expansion with different variation trends in the lattice constants. The increase of Sb concentration in the semiconductor–metal–semimetal transition occurs in consonance with the corresponding changes in its structural, electronic and optical properties. Two competing mechanisms play essential roles in this transition, namely; the many body effect and the atom disorder. Our calculations concur with previous X-ray diffraction, sheet resistance, resistivity and optical parameters detections. The studies present a practical way of tailoring the physical behaviors of Sn 1− x Sb x O 2 through the alloying technique.

Selective Preparation of SnO2 and SnO Crystals with Controlled Morphologies in an Aqueous Solution System

The oxidation state of tin oxide crystals grown in an aqueous solution of Sn(II) was successfully controlled. Rutile-type SnO2 and tetragonal SnO were selectively produced under acidic conditions below pH 3.3 and alkaline conditions above pH 13.1, respectively. The nanostructures, including the grain size and shape, and the mesoscopic assembled states of the crystals were changed with the concentration of the Sn(II) species and a subtle variation of the pH. This versatile fabrication process for functional oxides is based on the difference in the stability of Sn(II) and Sn(IV) depending on the pH in an aqueous solution system.

In situ119Sn-Mössbauer spectroscopic study on MR, MEL, and MTW tin silicalites

MFI, MEL, and MTW analogue tin silicalites were studied by in situ Mossbauer spectroscopy to complement previous studies. Series of 77 and 300 K spectra were obtained from synthesized, reduced, and oxidized samples. Intensity changes of components as a function of temperature (d lnA/dT values) were also considered in addition to the usual spectral parameters (isomer shift and quadrupole splitting) to evaluate the spectra. The data obtained for Sn(IV) support neither the octahedral nor the extraframework emplacement; instead, dominance of tetrahedral coordination is supported. Upon reduction in hydrogen a Sn(II) component is formed and can be stabilized. A significant portion of Sn(II) can be reoxidized to the Sn(IV) state by a subsequent medium oxidation. In view of the respective d lnA/dT values and the stabilization of Sn(II), the structural change of edge-sharing [SnO4/2] tetrahedra is suggested to form Si-O-Sn(II)-O-Si bridges. The existence of these bridges also can be correlated with the catalytic activity of tin silicalites observed in mild oxidation processes.

The stabilities of secondary tin minerals. Part 2: The hydrolysis of tin(II) sulphate and the stability of Sn3O(OH)2SO4

AbstractTritin(II)dihydroxyoxosulphate, Sn3O(OH)2SO4, is a rare corrosion product found on the surfaces of certain tin alloys. A new synthesis based on the hydrolysis of SnSO4 is described. The stability constant determination of Sn3O(OH)2SO4,s, at 298.2K and 105Pa is determined using direct measurements via electrodes, of the activities of tin(II) and sulphate ions. ΔfG0(298.2K) is equal to −1563.1 ± 0.9 KJ mol−1.

Deterioration of stannous ion in radiopharmaceutical kits during storage

The deterioration of stannous ion (Sn++) in inhouse-prepared and commercial radiopharmaceutical kits was studied. Sn++ content of three types of nonlyophilized, deoxygenated, aqueous inhouse-prepared kits [diethylenetriamine pentaacetic acid (DTPA), pyrophosphate and glucoheptonate] and of three commercially prepared kits (two lyophilized pyrophosphate kits and one diphosphonate in sealed glass ampul kit) was measured by differential pulse polarography. Inhouse-prepared kits were assayed initially and after storage for 6, 12, 24 and 48 days at 24, 5 and -18 C. Commercial kits were assayed initially and after storage for 12, 24 and 48 days at 5 and 24 C. Of the inhouse-prepared kits, Sn++ stability when stored for 48 days at 5 and 24 C. Freezer storage should be used, when possible, to insure maximum stability of Sn++ in inhouse-prepared, nonlyophilized ratiopharmaceutical kits. The commercial procedures of lyophilization and of sealing the reagent in a sealed glass ampul prolong Sn++ stability.

Relative stability and the strong law of large numbers

LetX1,X2,..., be i.i.d. random variables andSn=X1+X2+⋯. +Xn. In this paper we simplify Rogozin's condition forSn/Bn\(\xrightarrow{p}\) ±1for someBn→+∞, which generalises Hincin's condition for relative stability ofSn. We also consider convergence of subsequences ofSn/Bn. As an application of our methods, we extend a result of Chow and Robbins to show thatSn/Bn→±1 a.s. for someBn→ + ∞ if and only if 0<¦EX¦≦E¦X¦<+ ∞.