Tin Oxide Phases Research Articles

Improving the synthesis of heterogeneous catalysts by gliding arc plasma using the “no-cooling system”

Glidarc plasma (GP) is a promising method for preparing heterogeneous catalysts due to its mild conditions and short processing time. This technique has been used to synthesize various catalysts like FeOx and MnOx. Adding a post-discharge (PD) step during synthesis has been shown to impart valuable new properties, such as phase transformation, increased specific surface area, and enhanced catalytic activity. Knowing that the PD step mostly impacts the plasma-synthesized solids maturation and can be accelerated if heat is introduced into the system, we now contemplate the possibility of accelerating the GP catalysts synthesis by allowing the solution to be heated by the energy spontaneously provided by the plasma without the necessity to add a PD. To challenge this approach, we subjected FeSO4 and SnSO4 precursors to plasma exposure without employing the cooling system usually integrated in the GP set-up and compared the resulting solids with those obtained via conventional GP synthesis involving a PD step. The findings show that for iron precursors, the absence of cooling accelerates the formation of non-catalytically active phases and causes particle agglomeration, which is undesirable. However, for tin precursors, the absence of a cooling system introduces features that further improve the catalytic activity of the solids. Precisely, tin oxide phases developed better than other less-catalytically active ones without affecting the textural properties of the solid. This suggests that in some cases, eliminating the PD step can simplify the GP catalyst synthesis process and reduce its environmental and economic impact.

Highly Tuning of Sunlight-Photocatalytic Properties of SnO2 Nanocatalysts: Function of Gd/Fe Dopants

Gd/Fe-SnO2 nanopowders as novel photocatalysts for the active removal of Rose Bengal dye and methyl parathion pesticide were synthesized with a low-cost coprecipitation route. The X-ray diffraction analysis of SnO2, Sn0.96Gd0.02Fe0.02O2 and Sn0.94Gd0.02Fe0.04O2 nanopowders proved the formation of a tetragonal phase of tin oxide with average crystallite sizes in the range of 13–18 nm. The Fourier transform infrared (FTIR) spectra of all samples displayed the characteristic absorption bands of SnO2. The nanopowder of the pure SnO2 sample, as seen in its transmission electron microscope (TEM) image, contains spherical-like particles of variable sizes. The TEM images of the Sn0.96Gd0.02Fe0.02O2 and Sn0.94Gd0.02Fe0.04O2 powders revealed the synthesis of fine spherical nanoparticles. Based on the TEM images, the average particle size of the pure, (Gd, 2 wt% Fe) and (Gd, 4 wt% Fe) codoped SnO2 nanopowders was estimated to be 14, 10 and 12 nm, respectively. After the addition of (Gd, 2 wt% Fe) and (Gd, 4 wt% Fe) to the SnO2 structure, the band gap energy of SnO2 was reduced from 3.4 eV to 2.88 and 2.82 eV, respectively. Significantly, the Sn0.96Gd0.02Fe0.02O2 nanocatalyst exhibited a high removal efficiency of 98 and 96% for Rose Bengal dye and methyl parathion pesticide after activation by sunlight for 35 and 48 min, respectively. Furthermore, this catalyst has shown perfect mineralization as well as high stability properties for the treatment of Rose Bengal dye and methyl parathion pesticide. These results suggest the suitability of the Sn0.96Gd0.02Fe0.02O2 nanocatalyst for the treatment of agriculture and industrial effluent under sunlight light energy.

Peculiarities in XPS spectra of Sn/SiO2 layers as an effect of surface charge

X-ray photoelectron spectroscopy based on synchrotron radiation was used to investigate the composition of the observed SnO2-x/Sn:SiO2-x thin layer grown by organometallic chemical vapour deposition on single-crystalline silicon wafer with additional argon ions etching treatment. Due to the formation of a thermodynamic anomaly during in situ layer growth, an efficient oxygen exchange between silicon and tin oxide phases occurs. The present study addresses the effect of localized surface charging and its influence on the obtained XPS core level spectra. We found that due to the high electrical conductivity of metallic tin and the direct coupling of tin particles to the silicon wafer, the XPS Sn 3d5/2 core level spectrum is not affected by the surface charge compared to the highly charged dielectric silicon oxide matrix, as observed for the XPS O 1 s and Si 2p core level spectra. Our results show that the core level spectra of Si 2p and O 1 s are shifted up to 3 eV due to the presence of uncompensated positive charge on the surface of the silica matrix. These results provide insight into the influence of surface charge effects on the analysis of conductor/insulator composite materials and contribute to the application of Sn-based materials in various application concepts related to energy and surface functionalization.

Hydrogen Production Mechanism in Low-Temperature Methanol Decomposition Catalyzed by Ni3Sn4 Intermetallic Compound: A Combined Operando and Density Functional Theory Investigation.

Hydrogen production from methanol decomposition to syngas (H2 + CO) is a promising alternative route for clean energy transition. One major challenge is related to the quest for stable, cost-effective, and selective catalysts operating below 400 °C. We illustrate an investigation of the surface reactivity of a Ni3Sn4 catalyst working at 250 °C, by combining density functional theory, operando X-ray absorption spectroscopy, and high-resolution transmission electron microscopy. We discovered that the catalytic reaction is driven by surface tin-oxide phases, which protects the underlying Ni atoms from irreversible chemical modifications, increasing the catalyst durability. Moreover, we found that Sn content plays a key role in enhancing the H2 selectivity, with respect to secondary products such as CO2. These findings open new perspectives for the engineering of scalable and low-cost catalysts for hydrogen production.

Spectromicroscopy Studies of Silicon Nanowires Array Covered by Tin Oxide Layers.

The composition and atomic and electronic structure of a silicon nanowire (SiNW) array coated with tin oxide are studied at the spectromicroscopic level. SiNWs are covered from top to down with a wide bandgap tin oxide layer using a metal-organic chemical vapor deposition technique. Results obtained via scanning electron microscopy and X-ray diffraction showed that tin-oxide nanocrystals, 20nm in size, form a continuous and highly developed surface with a complex phase composition responsible for the observed electronic structure transformation. The "one spot" combination, containing a chemically sensitive morphology and spectroscopic data, is examined via photoemission electron microscopy in the X-ray absorption near-edge structure spectroscopy (XANES) mode. The observed spectromicroscopy results showed that the entire SiNW surface is covered with a tin(IV) oxide layer and traces of tin(II) oxide and metallic tin phases. The deviation from stoichiometric SnO2 leads to the formation of the density of states sub-band in the atop tin oxide layer bandgap close to the bottom of the SnO2 conduction band. These observations open up the possibility of the precise surface electronic structures estimation using photo-electron microscopy in XANES mode.

Synthesis and characterization of thermally evaporated Er-doped SnO2 thin films for photonic applications

In this study, different compositions of transparent films of erbium-doped tin oxide were created utilizing the thermal evaporation process on glass substrates. The tetragonal phase is verified by XRD analysis. The visible spectrum's strong transmittance was seen in the films. The films' transmission spectra ranged from 75 to 85% transmittance in the visible range with varying Er concentrations. Using Tauc's relation, values of the optical direct band gap have been calculated. The rutile phase of tin oxide is indicated by the Raman scattering peaks. PL measurements show thatonly the emission-related on a peak at 656 nm of Er3+ ions due to transition from 4I15/2 to 4F9/2 level and with the presence of doping, this emission becomes more intense. From the AFM measurements, the RMS roughness and grain size of films were computed. The results obtained show that these samples have wide applications in optoelectronic devices.

STUDY OF THE MICROSTRUCTURE AND PHASE FORMATION IN CERAMICS BASED ON Zn, Sn AND Ti OXIDES

Ceramics was obtained from the mixture of ZnO, SnO2 and TiO2 nanopowders by the method of solid-state sintering at 1123 K and 1443 K. The indicated nanopowders are used as components in arc dampers and for dispersion-strengthening in silver-based electrical contact materials. The phase formation and microstructure of the obtained material were studied by the methods of scanning electron microscopy, energy dispersive microanalysis and X-ray phase analysis. It is shown that at a sintering temperature of 1123 K a dispersed structure was formed, with the size of the Zn2TiO4 and ZnO phases being 0.5 – 1.0 µm. The solid phase reactions in the system ZnO/TiO2 at Тsint = 1123 K resulted in the formation of two-phase ceramics ZnO/Zn2TiO4 with the residual amounts of the phases of zinc and tin oxides. At Тsint = 1443 K there occurred the grain growth, Zn2SnO4 became the predominant phase and there remained a certain amount of the zinc and tin oxide phases.

Regulation of the photovoltaic performance of TiO2@MAPbI3 core–shell nanowire arrays

Abstract To further the exploration of perovskite nanowires, TiO2@CH3NH3PbI3 (TiO2@MAPbI3) core–shell nanowire arrays were successfully prepared via immersion and spin-coating methods. Because the shell thickness has a significant influence on the carrier transport capacity of nanowire arrays, different shell thicknesses were obtained by changing the precursor concentration. Subsequently, the relationship between the precursor concentration and shell thicknesses and the resulting properties of the nanowire arrays were investigated. The X-ray diffraction results showed that the prepared nanowire arrays consisted of only MAPbI3, TiO2, and fluorine-doped tin oxide phases, with no impurities. From the scanning electron microscopy and energy dispersive X-ray spectroscopy results, the MAPbI3 shell material was successfully coated onto the core layer of the TiO2 nanowire arrays. In addition, the average size of the core–shell nanowire arrays and the shell thickness were obtained using scanning electron microscopy and related software analyses. The results showed that the shell thickness was the largest (40 nm) when the precursor concentration was the lowest (0.025 mol L−1). Ultraviolet–visible spectroscopy showed that when the precursor concentration was 0.025 mol L−1 and the shell thickness was the largest, the nanowire array exhibited the highest absorbance and the smallest band gap, which is conducive to generating more carriers and improving its photovoltaic performance; the J–V curve showed the highest photoelectric conversion efficiency at this concentration and shell thickness. Therefore, it can be inferred that the shell thickness may affect the optical and photovoltaic properties. The relationship between the precursor concentration and thickness as well as the influence of this relationship on the properties of core–shell nanowire arrays should be further explored, to establish a foundation for the use of perovskite nanowires in the photovoltaic field.

Ultrafine Mix-Phase SnO-SnO2 Nanoparticles Anchored on Reduced Graphene Oxide Boost Reversible Li-Ion Storage Capacity beyond Theoretical Limit.

Tin-based materials with high specific capacity have been studied as high-performance anodes for Li-ion storage devices. Herein, a mix-phase structure of SnO-SnO2@rGO (rGO = reduced graphene oxide) was designed and prepared via a simple chemical method, which leads to the growth of tiny nanoparticles of a mixture of two different tin oxide phases on the crumbled graphene nanosheets. The three-dimensional structure of graphene forms the conductive framework. The as-prepared mix phase SnO-SnO2@rGO exhibits a large Brunauer-Emmett-Teller surface area of 255 m2 g-1 and an excellent ionic diffusion rate. When the resulting mix-phase material was examined for Li-ion battery anode application, the SnO-SnO2@rGO was noted to deliver an ultrahigh reversible capacity of 2604 mA h g-1 at a current density of 0.1 A g-1. It also exhibited superior rate capabilities and more than 82% retention of capacity after 150 charge-discharge cycles at 0.1 A g-1, lasting until 500 cycles at 1 A g-1 with very good retention of the initial capacity. Owing to the uniform defects on the rGO matrix, the formation of LiOH upon lithiation has been suggested to be the primary cause of this very high reversible capacity, which is beyond the theoretical limit. A Li-ion full cell was assembled using LiNi0.5Mn0.3Co0.2O2 (NMC-532) as a high-capacity cathodic counterpart, which showed a very high reversible capacity of 570 mA h g-1 (based on the anode weight) at an applied current density of 0.1 A g-1 with more than 50% retention of capacity after 100 cycles. This work offers a favorable design of electrode material, namely, mix-phase tin oxide-nanocarbon matrix, exhibiting adequate electrochemical performance for Li storage applications.

Enhancement in photocurrent conversion efficiency via recrystallization of zinc tin hydroxide nanostructures

Herein, the synthesis of cubic phase zinc tin hydroxide is reported by the hydrolysis assisted co-precipitation method followed by calcination in 150–850 °C. The recrystallization of zinc tin hydroxide (ZnSn(OH)6) to zinc tin oxide (Zn2SnO4) phase is observed with the intermediate amorphous phase (ZnSnO3) by increasing the calcination temperature. Increase in calcination temperature also causes the partial alteration in the cubic morphology and diminution in average particle size. The M-O-M and M-O vibration modes have distinct peaks in the FT-IR spectra below 1500 cm−1. Four Raman active vibration modes in ZnSn(OH)6 and two Raman active vibration modes in Zn2SnO4 phase are observed, while no Raman active mode is present in intermediate amorphous ZnSnO3. Chemical states of various elements and compositions are examined by X-ray photoelectron spectroscopy. The ZnSnO3 electrodes has the lowest charge transfer resistance and higher lifetime of the photogenerated charge carriers. Photoelectrochemical measurements rendered enhanced photocurrent density for ZnSnO3 and Zn2SnO4 phases, which is approximate 85 and 50 times higher as compared to ZnSn(OH)6 based photoelectrode, respectively. Due to crystalline nature, the Zn2SnO4 phase has better photo-stability.

Hierarchical Fe2O3 hexagonal nanoplatelets anchored on SnO2 nanofibers for high-performance asymmetric supercapacitor device

Metal oxide heterostructures have gained huge attention in the energy storage applications due to their outstanding properties compared to pristine metal oxides. Herein, magnetic Fe2O3@SnO2 heterostructures were synthesized by the sol–gel electrospinning method at calcination temperatures of 450 and 600 °C. XRD line profile analysis indicated that fraction of tetragonal tin oxide phase compared to rhombohedral hematite was enhanced by increasing calcination temperature. FESEM images revealed that hexagonal nanoplatelets of Fe2O3 were hierarchically anchored on SnO2 hollow nanofibers. Optical band gap of heterogeneous structures was increased from 2.06 to 2.40 eV by calcination process. Vibrating sample magnetometer analysis demonstrated that increasing calcination temperature of the samples reduces saturation magnetization from 2.32 to 0.92 emu g-1. The Fe2O3@SnO2-450 and Fe2O3@SnO2-600 nanofibers as active materials coated onto Ni foams (NF) and their electrochemical performance were evaluated in three and two-electrode configurations in 3 M KOH electrolyte solution. Fe2O3@SnO2-600/NF electrode exhibits a high specific capacitance of 562.3 F g-1 at a current density of 1 A g-1 and good cycling stability with 92.8% capacitance retention at a high current density of 10 A g-1 after 3000 cycles in three-electrode system. The assembled Fe2O3@SnO2-600//activated carbon asymmetric supercapacitor device delivers a maximum energy density of 50.2 Wh kg-1 at a power density of 650 W kg-1. The results display that the Fe2O3@SnO2-600 can be a promising electrode material in supercapacitor applications.

Mutual Stabilization of Metastable Phases of Tin Oxide: Epitaxial Encapsulation of Tetragonal SnO Microcrystals by Orthorhombic SnO2

Mutual Stabilization of Metastable Phases of Tin Oxide: Epitaxial Encapsulation of Tetragonal SnO Microcrystals by Orthorhombic SnO₂

The Effect of Different Nanomaterials Additions in Clay-Based Composites on Electromagnetic Transmission.

In this study, clay composites were subjected to electromagnetic transmission testing at frequencies in the region of non-ionizing radiation. Specimens were made with partial substitution of clay with different admixtures by mass. Admixtures used were Fly Ash, four different particle sizes and phases of Titanium Dioxide (TiO2), Zinc Ferrite (ZnFe2O4), Maghemite (γ-Fe2O3) and Antimony Tin Oxide (ATO). The additives were thoroughly (chemically, structurally, morphologically) characterized. The replacement percentage was 5 wt.%. Electromagnetic transmission assessment included S21 transmission coefficient measurements for samples with different additives. The lowest transmission was reported for the clay specimens with ATO and Titanium Dioxide, especially at higher frequencies. A decrease in the transmission parameter with increasing specimen thickness was also confirmed.

Synthesis and Characterization of a Transparent PMMA Based Triboelectric Nanogenerator for Wearable Electronic Applications

With the increase in energy consumption with unprecedented rate, there is an urgent need for the development of independent, efficient and maintenance free power sources. With the growing emergence of flexible, wearable electronic devices in the current market, the requirement for portable and highly flexible power sources has also increased many folds. The electronic devices such as stretchable circuits [1], e-papers [2], bendable displays [3], e-skins [4], wearable electronic devices [5], etc. are receiving wide attention due to their applications in robotics, medical science, human machine interface, fitness trackers, smart watches and many more. The waste mechanical energy in the environment such as vibration, wind and human body motions can be converted into electricity by triboelectric energy harvesting technologies [6]. Energy is one of the essential requirements of the society and it is necessary to search newly and highly efficient technologies that harvest many forms of energy from the environment which is generally wasted. For the last two decades, the scientists and researchers have been focused on the synthesis and characterization of novel source of energy harvesting and self-powered devices useful for numerous energy applications without external inputs.In this paper, a novel triboelectric nanogenerator (TENG) based on Polymethyl methacrylate (PMMA) as transparent and flexible polymer materials with gold nanoparticles (AuNPs) has been synthesized and characterized. The SEM image clearly reveals the spherical shape of the synthesized AuNPs. The XRD pattern of the prepared material shows accurate diffraction peaks at 2theta values indicate the presence of mixed phases of fluorine tin oxide (SnO2), AuNPs, and metallic copper (Cu) which are in excellent agreement with the previously mentioned 2theta values in the literature. Further, the EDS analysis confirms the presence of Sn, Au, O, and Cu within the synthesized TENG. Finally, the proposed synthesize PMMA-based TENG produces maximum AC output voltage and current signal up to 5V and 10 μA, respectively with very high transmittance of 100 %. The electric energy in terms of AC voltage produced by synthesized PMMA-based TENG is further converted into DC voltage which is used to light up light - emitting diodes in future.The synthesized TENG consists of two parts such as lower part and upper part. The spacer (sponge or spring) is placed between the upper part as well as the lower part. The synthesized lower part of TENG consists of three layers such as (a) fluorine tin oxide (FTO), (b) copper (Cu), and (c) gold nanoparticles (AuNPs) whereas the upper part of the synthesized TENG consists of two layers such as (a) aluminum (Al) and (b) polymethyl methacrylate (PMMA) transparent and flexible polymer. By taking FTO substrate, we first deposit the copper layer with micrometer range of thickness on the top of FTO with the help of Magnetron Sputtering technique at 5.8 X 10-2 m bar base working pressure, 60 sccm gas-flow, 200 W power, 200˚C temperature for 5 minutes. Next, the freshly prepared AuNPs are prepared by using the following steps: (A) Seed solution preparation; (B) Growth solution preparation; and (C) Washing the gold nanoparticles:- By centrifugation process, only the gold nanoparticles remains and the other byproducts in the form of liquid is removed.The spherical shape of the synthesized AuNPs has been observed within the SEM image. The XRD pattern of the prepared sample indicates the diffraction peaks of SnO2, AuNPs, and metallic Cu at different 2theta values. The EDS analysis further confirms the presence of Sn, Au, O, and Cu materials within the synthesized lower part of TENG while the UV-Visible spectroscopy analysis clearly shows 100 % light transmission and ~0 % light absorption of transparent and flexible PMMA polymer material used for synthesis of TENG. References Hu, H. S. Kim, J. Y. Lee, P. Peumans, Y. Cui, ACS Nano 4 (2010) 2955-2963. Chen, J. Au, P. Kazlas, A. Ritenour, H. Gates, M. McCreary, Nature 423 (2003) 136-136. Yoon, D.Y Ham, O. Yarimaga, H. An, C.W. Lee, J.M. Kim, Advanced Materials 23 (2011) 5492-5497. Hu, R. Xiong, H. Guo, R. Ma, S. Zhang, Z. L. Wang, V. V. Tsukruk, Advanced Materials 28 (2016) 3549-3556. S. Rim, S. H. Bae, H. Chen, J. L. Yang, J. Kim, A. M. Andrews, P. S. Weiss, Y. Yang, H. R. Tseng, ACS Nano 9 (2015) 12174-12181.W. Kim, J. H. Lee, J. K. Kim, U. Jeong, NPG Asia Materials 12 (2020) 6. Figure 1

Mechanochemical preparation of NiCuSn nanoparticles and composites in presence of cetyltrimethylammonium bromide (CTAB) and the catalytic application of the products in homocoupling and hydration of terminal alkynes

We report the synthesis of the NiCuSn nanoparticles and nanocomposites in mechanochemical route using CTAB as milling additive. The study of grinding intensity (frequency) and time interval drew up the importance of the well-chosen operation parameters. The mild milling resulted in formation of NiSn intermetallics, while the intense ones aided the evolution of bronze and copper(I) oxide phases. The utilization of CTAB proved to be the key factor to prevent or slow down the process of mechanical alloying and to fritter the metal grains into the nanodimensions. The dynamic light scattering data demonstrated positively charged particles with average solvodynamic diameters of around 70 nm applying intense or long-term millings. Without CTAB or with relatively short or weak grindings, these values remained between 230 and 550 nm, as in the case of the surface areas getting around 20 m2/g with and 1 m2/g without CTAB. The catalytic transformation of p-methoxyphenylacetylene in dimethyl sulfoxide showed that the copper, copper(I) oxide and bronze particles managed the reaction toward the evolution of 1,3-diyne in Glaser-Hay homocoupling without base addition, while the Sn and SnO2 phases assisted to the Markovnikov-type hydration of alkyne groups. The formation of α-diketone signed that the anti-Markovnikov route was also occurred. The use of CTAB was found to exert a profound effect on the quality of catalytic end-products through the controlled generation of bronze and tin oxide phases and the solid solution of nickel atoms.

Additive-Assisted Optimization in Morphology and Optoelectronic Properties of Inorganic Mixed Sn-Pb Halide Perovskites.

Halide perovskite solar cells (HPSCs) are promising photovoltaic materials due to their excellent optoelectronic properties, low cost, and high efficiency. Here, we demonstrate atmospheric solution processing and stability of cesium tin-lead triiodide (CsSnPbI3) thin films for solar cell applications. The effect of additives, such as pyrazine and guanidinium thiocyanate (GuaSCN), on bandgap, film morphology, structure, and stability is investigated. Our results indicate the formation of a wide bandgap (>2 eV) structure with a mixed phase of tin oxide (SnO2) and Cs(Sn, Pb)I3. The addition of pyrazine decreases the intensity of SnO2 peaks, but the bandgap does not change much. With the addition of GuaSCN, the bandgap of the films reduces to 1.5 eV, and a dendritic structure of Cs(Sn, Pb)I3 is observed. GuaSCN addition also reduces the oxygen content in the films. To enable uniform film crystallization, cesium chloride (CsCl) and dimethyl sulfoxide (DMSO) additives are used in the precursor. Both CsCl and DMSO suppress dendrite formation with the latter resulting in uniform polycrystalline films with a bandgap of 1.5 eV. Heat and light soaking (HLS) stability tests at 65 °C and 1 sun for 100 h show all film types are stable with temperature but result in phase segregation with light exposure.

Antibacterial Activity of Undoped and Cu2+ Doped Tin Oxide Nanoparticles Synthesized by Microwave Irradiated Solvothermal Method

In present work, a simple and facile microwave irradiated solvothermal method was applied for the synthesis of undoped and Cu2+ doped tin oxide nanoparticles. Thermal characterization was performed to study the thermal stability and to fix the annealing temperature. All the prepared samples were annealed at 500 ºC and then characterized. Structural, morphological and optical characterizations were done using PXRD, TEM, SEM and UV-Vis NIR analysis. The PXRD measurement shows the tetragonal phase of tin oxide. Agglomerated and spherical morphology was observed in SEM and TEM micrographs. Presence of blue shift was observed in the absorption spectra of the prepared samples. Elemental compositions of the samples were analyzed using EDX patterns. Magnetic characterization was performed using vibrating sample magnetometer and the analysis revealed that the prepared samples were diamagnetic in nature. Antibacterial studies showed the efficient activity against the Gram-positive and Gram-negative bacterial stains.

Understanding the Origin of the Hysteresis of High-Performance Solution Processed Polycrystalline SnO2 Thin-Film Transistors and Applications to Circuits.

Crystalline tin oxide has been investigated for industrial applications since the 1970s. Recently, the amorphous phase of tin oxide has been used in thin film transistors (TFTs) and has demonstrated high performance. For large area electronics, TFTs are well suited, but they are subject to various instabilities due to operating conditions, such as positive or negative bias stress PBS (NBS). Another instability is hysteresis, which can be detrimental in operating circuits. Understanding its origin can help fabricating more reliable TFTs. Here, we report an investigation on the origin of the hysteresis of solution-processed polycrystalline SnO2 TFTs. We examined the effect of the carrier concentration in the SnO2 channel region on the hysteresis by varying the curing temperature of the thin film from 200 to 350 °C. Stressing the TFTs characterized further the origin of the hysteresis, and holes trapped in the dielectric are understood to be the main source of the hysteresis. With TFTs showing the smallest hysteresis, we could fabricate inverters and ring oscillators.

Overcoming the Challenges of Freestanding Tin Oxide‐Based Composite Anodes to Achieve High Capacity and Increased Cycling Stability

AbstractFreestanding electrodes are a promising way to increase the energy density of the batteries by decreasing the overall amount of electrochemically inactive materials. Freestanding antimony doped tin oxide (ATO)‐based hybrid materials have not been reported so far, although this material has demonstrated excellent performance in conventionally designed electrodes. Two different strategies, namely electrospinning and freeze‐casting, are explored for the fabrication of ATO‐based hybrid materials. It is shown that the electrospinning of ATO/carbon based electrodes from polyvinyl pyrrolidone polymer (PVP) solutions was not successful, as the resulting electrode material suffers from rapid degradation. However, freestanding reduced graphene oxide (rGO) containing ATO/C/rGO nanocomposites prepared via a freeze‐casting route demonstrates an impressive rate and cycling performance reaching 697 mAh g−1 at a high current density of 4 A g−1, which is 40 times higher as compared to SnO2/rGO and also exceeds the freestanding SnO2‐based composites reported so far. Antimony doping of the nanosized tin oxide phase and carbon coating are thereby shown to be essential factors for appealing electrochemical performance. Finally, the freestanding ATO/C/rGO anodes are combined with freestanding LiFe0.2Mn0.8PO4/rGO cathodes to obtain a full freestanding cell operating without metal current collector foils showing nonetheless an excellent cycling stability.

The Potassium‐Assisted P‐Type Characteristics of Tin Oxide in Solution‐Processed High‐Performance Metal Oxide Thin‐Film Transistors

Developing high‐performance p‐type metal‐oxide semiconductors comparable to n‐type ones has opened a new window for the realization of transparent, flexible, and low‐power integrated circuits in large‐area electronics. Herein, the fabrication of solution‐processed p‐type metal‐oxide thin‐film transistors (TFTs) with excellent device performance at low temperatures using a novel material is reported. Potassium (K) content is introduced into the tin oxide precursor solution to stabilize the tin (II) oxide (SnO) phase rather than the tin (IV) oxide (SnO2) phase during thin‐film formation. The optimized K‐doped SnO (K‐SnO) TFTs exhibit outstanding electrical performance, with a maximum Hall mobility of 51 cm2 V−1 s−1 and a field‐effect hole mobility of 2.3 cm2 V−1 s−1. The achievement of the solution‐processed K‐SnO TFTs not only provides a significant step toward the development of complementary metal‐oxide semiconductor circuits, but also represents a feasible approach for low‐cost flexible p‐type metal‐oxide electronics.