Controlled Growth of Two-Dimensional SnSe/SnS Core/Crown Heterostructures.

We present a novel, straightforward, and reproducible one-pot heating up technique to synthesize core/crown SnSe/SnS nanosheets by a careful adjustment of the sulfur and selenium precursor reactivity. Here, the SnSe nanosheets are prepared via a wet-chemical route using SnCl2 and selenium phosphines. By adding a highly reactive S-oleylamine complex during the growth of the SnSe sheets at 240 °C, SnS crowns were formed within the SnSe sheets. The number of SnS crowns can be tailored upon repeated addition of S-oleylamine. A combination of transmission electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy proves the formation of highly crystalline core/crown structures.

High-Performance Sodium-Ion Batteries Enabled by 3D Nanoflowers Comprised of Ternary Sn-Based Dichalcogenides Embedded in Nitrogen and Sulfur Dual-Doped Carbon.

To make sodium-ion batteries a realistic option for everyday energy storage, a practicable method is to enhance the kinetics of Na+ reactions through the development of structurally stable electrode materials. This study utilizes ternary Sn-based dichalcogenide (SnS1.5 Se0.5 ) in the design of electrode material to tackle several issues that adversely hinder the performance and longevity of sodium-ion batteries. First, the incorporation of Se into the SnS structure enhances its electrical conductivity and stability. Second, the ternary composition restricts the formation of intermediates during the desodiation/sodiation process, resulting in better electrode reaction reversibility. Finally, SnS1.5 Se0.5 lowers the diffusion barrier of Na, thereby facilitating rapid and efficient ion transport within the electrode material. Moreover, nitrogen and sulfur dual-doped carbon (NS-C) is used to enhance surface chemistry and ionic/electrical conductivity of SnS1.5 Se0.5 , leading to a pseudocapacitive storage effect that presents a promising potential for high-performance energy storage devices. The study has successfully developed a SnS1.5 Se0.5 /NS-C anode, exhibiting remarkable rate capability and cycle stability, retaining a capacity of 647 mAh g-1 even after 10 000 cycles at 5 A g-1 in half-cell tests. In full-cell tests, Na3 V2 (PO4 )3 //SnS1.5 Se0.5 /NS-C delivers a high energy density of 176.6 Wh kg-1 . In addition, the Na+ storage mechanism of SnS1.5 Se0.5 /NS-C is explored through ex situ tests and DFT calculations. The findings suggest that the ternary Sn-based dichalcogenides can considerably enhance the performance of the anode, enabling efficient large-scale storage of sodium. These findings hold great promise for the advancement of high-performance energy storage devices for practical applications.

Lithium Azides Induced SnS Quantum Dots for Ultra-Fast and Long-Term Sodium Storage.

Tin sulfide (SnS) is an attractive anode for sodium ion batteries (NIBs) because of its high theoretical capacity, while it seriously suffers from the inherently poor conductivity and huge volume variation during the cycling process, leading to inferior lifespan. To intrinsically maximize the sodium storage of SnS, herein, lithium azides (LiN3 )-induced SnS quantum dots (QDs) are first reported using a simple electrospinning strategy, where SnS QDs are uniformly distributed in the carbon fibers. Taking the advantage of LiN3 , which can effectively prevent the growth of crystal nuclei during the thermal treatment, the well-dispersed SnS QDs performs superior Na+ transfer kinetics and pseudocapacitive when used as an anode material for NIBs. The 3D SnS quantum dots embedded uniformly in N-doped nanofibers (SnS QDs@NCF) electrodes display superior long cycling life-span (484.6 mAh g-1 after 5800 cycles at 2 A g-1 and 430.9 mAh g-1 after 7880 cycles at 10 A g-1 ), as well as excellent rate capability (422.3 mAh g-1 at 20 A g-1 ). This fabrication of transition metal sulfides QDs composites provide a feasible strategy to develop NIBs with long life-span and superior rate capability to pave its practical implementation.

A novel electrochemical immunosensor based on SnS2/NiCo metal-organic frameworks loaded with gold nanoparticles for cortisol detection.

In this work, a label-free electrochemical immunosensor using tin sulfide/nickel cobalt metal-organic frameworks (SnS2/NiCo MOFs) was established for the sensitive detection of cortisol. First, SnS2/NiCo MOFs were synthesized by doping SnS2 with NiCo MOF nanocubes by a hydrothermal method. Then, gold nanoparticles (AuNPs) were grown in situ on SnS2/NiCo MOFs for electrochemical detection. The use of SnS2/NiCo MOFs promoted the electron transfer rate of AuNPs and enhanced the electrochemical sensing performance of AuNPs@SnS2/NiCo MOFs-modified electrodes. The large specific surface area of AuNPs@SnS2/NiCo MOFs provides more active sites for antibody loading. After the prepared immunosensor was incubated with the target analyte, cortisol, the electron transfer impedance increased and the amperometric response decreased, thus establishing a highly sensitive immunosensing method. The sensor had a linear range of 100 fg/mL to 100 ng/mL and a low detection limit of 29 fg/mL. The sensor showed good accuracy and practicability and could be used for the determination of cortisol in saliva.

Imaging Anisotropic Waveguide Exciton Polaritons in Tin Sulfide.

In recent years, novel materials supporting in-plane anisotropic polaritons have attracted a great deal of research interest due to their capability of shaping nanoscale field distributions and controlling nanophotonic energy flows. Here we report a nano-optical imaging study of waveguide exciton polaritons (EPs) in tin sulfide (SnS) in the near-infrared (near-IR) region using scattering-type scanning near-field optical microscopy (s-SNOM). With s-SNOM, we mapped in real space the propagative EPs in SnS, which show sensitive dependence on the excitation energy and sample thickness. Moreover, we found that both the polariton wavelength and propagation length are anisotropic in the sample plane. In particular, in a narrow spectral range from 1.32 to 1.44 eV, the EPs demonstrate quasi-one-dimensional propagation, which is rarely seen in natural polaritonic materials. A further analysis indicates that the observed polariton anisotropy originates from the different optical band gaps and exciton binding energies along the two principal crystal axes of SnS.

Desulfurization-Induced Formation of Amorphized Substoichiometric Tin Sulfide for Super High-Rate Capacity and Degradation-Free Cycling of Na Ion Storage.

This work reports an amorphization and partial desulfurization method to improve the performance of sulfide-based materials for Na+ storage. Specifically, the polypyrrole derived carbon coated amorphous substoichiometric tin sulfide supported on aminated carbon nanotubes (PPY-C@SnSx /ACNTs) with amorphized and substoichiometric tin sulfide (SnSx ) is synthesized by simply thermal annealing the PPY-C@SnS2 /ACNTs. The PPY-C@SnSx /ACNTs shows stable reversible capacities of 410.2 mAh g-1 for Na+ storage at 0.1 A g-1 and excellent rate capacities of 270.2, 235.5, 217.4, and 210.0 mAh g-1 at 5.0, 10.0, 20.0, and 30.0 A g-1 , respectively. Nearly zero drops on the reversible capacities can be observed when it is sodiated/desodiated at 2.0, 5.0, and 10.0 A g-1 for up to 1000, 6500, 8000 cycles, respectively. Its outstanding rate capacities and degradation-free cycling stabilities mainly arise from the amorphized and substoichiometric structure of SnSx , which improve the reversible capacities and Na+ diffusivities of the PPY-C@SnSx /ACNTs. The density functional theory (DFT) calculations indicate that the partial desulfurization can improve the electric conductivity and promote the sodiation/desodiation of SnSx . It explains why the PPY-C@SnSx /ACNTs can exhibit high performance for Na+ storage well.

Hydrogen-Induced Conversion of SnS2 into SnS or Sn: A Route to Create SnS2 /SnS Heterostructures.

The family of van der Waals (vdW) materials is large and diverse with applications ranging from electronics and optoelectronics to catalysis and chemical storage. However, despite intensive research, there remains significant knowledge-gaps pertaining to their properties and interactions. One such gap is the interaction between these materials and hydrogen, a potentially vital future energy vector and ubiquitous processing gas in the semiconductor industry. This work reports on the interaction of hydrogen with the vdW semiconductor SnS2 , where molecular hydrogen (H2 ) and H-ions induce a controlled chemical conversion into semiconducting-SnS or to ß-Sn. This hydrogen-driven reaction is facilitated by the different oxidation states of Sn and is successfully applied to form SnS2 /SnS heterostructures with uniform layers, atomically flat interfaces and well-aligned crystallographic axes. This approach is scalable and offers a route for engineering materials at the nanoscale for semiconductor technologies based on the earth-abundant elements Sn and S, a promising result for a wide range of potential applications.

The atomic layer deposition (ALD) synthesis of copper-tin sulfide thin films using low-cost precursors.

In this work we demonstrated the process of co-deposition of copper-tin sulfide species by the atomic layer deposition (ALD) technique using all-low-cost precursors. For the deposition of tin species, the tin(IV) chloride SnCl4was used successfully for the first time in the ALD process. Moreover, we showed that the successful deposition of the tin sulfide component was conditioned by the pre-deposition of CuSxlayer. The co-deposition of copper and tin sulfides components at 150 °C resulted in the in-process formation of the film containing Cu2SnS3, Cu3SnS4andπ-SnS phases. The process involving only tin precursor and H2S did not produce the SnSxspecies. The spectroscopic characteristic of the obtained materials were confronted with the literature survey, allowing us to discuss the methodology of the determination of ternary and quaternary sulfides purity by Raman spectroscopy. Moreover, the material characterisation with respect to the morphology (SEM), phase composition (XRD), surface chemical states (XPS), optical properties (UV-vis-NIR spectroscopy) and electric (Hall measurements) properties were provided. Finally, the obtained material was used for the formation of the p-n junction revealing the rectifyingI-Vcharacteristics.

The microwave properties of tin sulfide thin films prepared by RF magnetron sputtering techniques.

In this paper we present the microwave properties of tin sulfide (SnS) thin films with the thickness of just 10 nm, grown by RF magnetron sputtering techniques on a 4 inch silicon dioxide/high-resistivity silicon wafer. In this respect, interdigitated capacitors in coplanar waveguide technology were fabricated directly on the SnS film to be used as both phase shifters and detectors, depending on the ferroelectric or semiconductor behaviour of the SnS material. The ferroelectricity of the semiconducting thin layer manifests itself in a strong dependence of the electrical permittivity on the applied DC bias voltage, which induces a phase shift of 30 degrees mm-1at 1 GHz and of 8 degrees mm-1at 10 GHz, whereas the transmission losses are less than 2 dB in the frequency range 2-20 GHz. We have also investigated the microwave detection properties of SnS, obtaining at 1 GHz a voltage responsivity of about 30 mV mW-1in the unbiased case and with an input power level of only 16µW.

Ultrathin tin sulfide field-effect transistors with subthreshold slope below 60 mV/decade.

In this paper, we present for the first time a field-effect-transistor (FET) having a 10 nm thick tin sulfide (SnS) channel fabricated at the wafer scale with high reproducibility. SnS-based FETs are in on-state for increasing positive back-gate voltages up to 6 V, whereas the off-state is attained for negative back-gate voltages not exceeding -6 V, the on/off ratio being in the range 102-103depending on FET dimensions. The SnS FETs show a subthreshold slope (SS) below 60 mV/decade thanks to the in-plane ferroelectricity of SnS and attaining a minimum value SS = 21 mV/decade. Moreover, the low SS values can be explained by the existence of a negative value of the capacitance of the SnS thin film up to 10 GHz (for any DC bias voltage between 1 and 5 V), with the minimum value being -12.87 pF at 0.1 GHz.

Realization of Large Scale, 2D van der Waals Heterojunction of SnS2 /SnS by Reversible Sulfurization.

2D van der Waals heterojunction provides an attractive opportunity for realizing novel electronic or optoelectronic devices. It remains challenging to realize high-quality heterostructures through scalable methods such as molecular epitaxy growth (MBE). Here, growth of few-layer SnS thin films is reported on mica and Nb-doped SrTiO3 (100) substrates by MBE. Then the top layer of SnS film is uniformly sulfurized to monolayer SnS2 in a sulfur atmosphere, resulting in a high-quality SnS2 /SnS 2D heterojunction. Furthermore, the SnS2 layer can be recovered to SnS by annealing SnS2 /SnS without sulfur supply, indicating the heterojunction formation is reversible. The scanning tunneling spectroscopy measurements on SnS2 /SnS heterostructure indicate the type-II band alignment in SnS2 /SnS. The work provides a promising approach to construct artificial 2D heterojunctions with desired properties, which could be extended to other sulfide and selenide systems.

Vapor Phase Synthesis of SnS Facilitated by Ligand-Driven "Launch Vehicle" Effect in Tin Precursors.

Extraordinary low-temperature vapor-phase synthesis of SnS thin films from single molecular precursors is attractive over conventional high-temperature solid-state methods. Molecular-level processing of functional materials is accompanied by several intrinsic advantages such as precise control over stoichiometry, phase selective synthesis, and uniform substrate coverage. We report here on the synthesis of a new heteroleptic molecular precursor containing (i) a thiolate ligand forming a direct Sn-S bond, and (ii) a chelating O^N^N-donor ligand introducing a "launch vehicle"-effect into the synthesized compound, thus remarkably increasing its volatility. The newly synthesized tin compound [Sn(SBut)(tfb-dmeda)] 1 was characterized by single-crystal X-ray diffraction analysis that verified the desired Sn:S ratio in the molecule, which was demonstrated in the direct conversion of the molecular complex into SnS thin films. The multi-nuclei (1H, 13C, 19F, and 119Sn) and variable-temperature 1D and 2D NMR studies indicate retention of the overall solid-state structure of 1 in the solution and suggest the presence of a dynamic conformational equilibrium. The fragmentation behavior of 1 was analyzed by mass spectrometry and compared with those of homoleptic tin tertiary butyl thiolates [Sn(SBut)2] and [Sn(SBut)4]. The precursor 1 was then used to deposit SnS thin films on different substrates (FTO, Mo-coated soda-lime glass) by CVD and film growth rates at different temperatures (300-450 °C) and times (15-60 min), film thickness, crystalline quality, and surface morphology were investigated.

Few-Layered Tin Sulfide Nanosheets Supported on Reduced Graphene Oxide as a High-Performance Anode for Potassium-Ion Batteries.

Anodes involving conversion and alloying reaction mechanisms are attractive for potassium-ion batteries (PIBs) due to their high theoretical capacities. However, serious volume change and metal aggregation upon potassiation/depotassiation usually cause poor electrochemical performance. Herein, few-layered SnS2 nanosheets supported on reduced graphene oxide (SnS2 @rGO) are fabricated and investigated as anode material for PIBs, showing high specific capacity (448 mAh g-1 at 0.05 A g-1 ), high rate capability (247 mAh g-1 at 1 A g-1 ), and improved cycle performance (73% capacity retention after 300 cycles). In this composite electrode, SnS2 nanosheets undergo sequential conversion (SnS2 to Sn) and alloying (Sn to K4 Sn23 , KSn) reactions during potassiation/depotassiation, giving rise to a high specific capacity. Meanwhile, the hybrid ultrathin nanosheets enable fast K storage kinetics and excellent structure integrity because of fast electron/ionic transportation, surface capacitive-dominated charge storage mechanism, and effective accommodation for volume variation. This work demonstrates that K storage performance of alloy and conversion-based anodes can be remarkably promoted by subtle structure engineering.

3D Porous Nanoarchitectures Derived from SnS/S-Doped Graphene Hybrid Nanosheets for Flexible All-Solid-State Supercapacitors.

3D porous nanoarchitectures derived from SnS/S-doped graphene hybrid nanosheets are successfully prepared by controllable thermal conversion of oleylamine-capped mixed-phase SnS2 -SnS nanodisks precursors, and employed as electroactive material to fabricate flexible, symmetric, all-solid-state supercapacitors. The fabricated solid devices exhibit very high areal specific capacitance (2.98 mF cm-2 ), good cycling stability (99% for 10 000 cycles), excellent flexibility, and desirable mechanical stability.

Tin Sulfide-Based Nanohybrid for High-Performance Anode of Sodium-Ion Batteries.

Nanohybrid anode materials for Na-ion batteries (NIBs) based on conversion and/or alloying reactions can provide significantly improved energy and power characteristics, while suffering from low Coulombic efficiency and unfavorable voltage properties. An NIB paper-type nanohybrid anode (PNA) based on tin sulfide nanoparticles and acid-treated multiwalled carbon nanotubes is reported. In 1 m NaPF6 dissolved in diethylene glycol dimethyl ether as an electrolyte, the above PNA shows a high reversible capacity of ≈1200 mAh g-1 and a large voltage plateau corresponding to a capacity of ≈550 mAh g-1 in the low-voltage region of ≈0.1 V versus Na+ /Na, exhibiting high rate capabilities at a current rate of 1 A g-1 and good cycling performance over 250 cycles. In addition, the PNA exhibits a high first Coulombic efficiency of ≈90%, achieving values above 99% during subsequent cycles. Furthermore, the feasibility of PNA usage is demonstrated by full-cell tests with a reported cathode, which results in high specific energy and power values of ≈256 Wh kg-1 and 471 W kg-1 , respectively, with stable cycling.

SnS 3D Flowers with Superb Kinetic Properties for Anodic Use in Next-Generation Sodium Rechargeable Batteries.

Tin sulfide (SnS) 3D flowers containing hierarchical nanosheet subunits are synthesized using a simple polyol process. The Li ion cells incorporating SnS 3D flowers exhibit an excellent rate capability, as well as good cycling stability, compared to SnS bulks and Sn nanoparticles. These desirable properties can be attributed to their unique morphology having not only large surface reaction area but also enough space between individual 2D nanosheets, which alleviates the pulverization of SnS.

Dual-Driven Ion/Electron Migration and Sodium Storage by In Situ Introduction of Copper Ions and a Carbon-Conductive Framework in a Tin-Based Sulfide Anode.

Tin sulfide (SnS) has emerged as a promising anode material for sodium ion batteries (SIBs) due to its high theoretical capacity and large interlayer spacing. However, several challenges, such as severe insufficient electrochemical reactivity, rapid capacity degradation, and poor rate performance, still hinder its application in SIBs. In this study, in situ introduction of copper ions and a carbon conductive framework to form SnS nanocrystals embedded in a Cu2SnS3 lamellar structure heterojunction composite (SnS/Cu2SnS3/RGO) with graphene as the supporting material is proposed to achieve dual-driven sodium ion/electron migration during the continuous electrochemical process. The designed structure facilitates the preferential electrochemical reduction of copper ions into copper nanocrystals during the discharge process and functions as a catalytically active center to promote multivalence tin sodiation reaction. Furthermore, during the charging process, the presence of copper nanocrystals also facilitates efficient desodiation of NaxSn and further activates to form higher valence state sulfides. As a result, the SnS/Cu2SnS3/RGO composite demonstrates high cycling stability with a high reversible capacity of 395 mAh g-1 at 5A g-1 after 500 cycles with a capacity retention of 85.6%. In addition, the assembled Na3V2(PO4)3∥SnS/Cu2SnS3/RGO sodium ion full cell achieves 93.7% capacity retention after 80 cycles at 0.5 A g-1.

Flower-like 3D SnS decorated on nickel metal-organic framework for electrochemical detection of dimetridazole in food samples.

Dimetridazole (DMZ) is a broad-spectrum antibiotic effective against bacterial and protozoan infections in humans and poultry farms. However, excessive DMZ intake leads to harmful effects. Thus, minimizing its environmental presence is crucial for sustaining daily life. This study presents an innovative approach to construct flower-like SnS particle decorations on a nickel metal-organic framework (Ni-MOF@SnS) as an electrocatalyst for DMZ detection. The Ni-MOF@SnS/GCE sensor exhibits exceptional electrocatalytic behavior, including a significantly reduced detection limit of 1.6 nM, extensive linear ranges from 0.01 µM to 60 µM and from 60 µM to 231 µM at lower and higher DMZ concentrations, respectively. It also shows enhanced sensitivity (0.139 µA µM-1 cm-2) and remarkable selectivity for DMZ detection using differential-pulse voltammetry (DPV). Furthermore, the proposed sensor demonstrates good recovery results with actual food samples.

Arc-Discharge In Situ Synthesis of Dual-Carbonaceous-Layer-Coated SnS Nanoparticles with High Lithium-Ion Storage Capacity.

SnS-based carbon composites have garnered considerable concentration as prospective anode materials (AMs) for lithium-ion batteries (LIBs). Nevertheless, most SnS-based carbon composites underwent a two-phase or multistep preparation process and exhibited unsatisfactory LIB performance. In this investigation, we introduce a straightforward and efficient one-step arc-discharge technique for the production of dual-layer carbon-coated tin sulfide nanoparticles (SnS@C). The as-prepared composite is used as an AM for LIBs and delivers a high capacity of 1000.4 mAh g-1 at 1.0 A g-1 after 520 cycles. The SnS@C still maintains a capacity of 476 mAh g-1 after 390 cycles despite a higher current of 5.0 A g-1. The high specific capacity and long life are mainly attributed to a unique dual-carbon layers coating structure. The dual-carbon layers not only could effectively improve electrical conductivity and reduce charge-transfer resistance but also limit the alteration in bulk and self-aggregation of SnS nanoparticles. The SnS@C produced by the arc-discharge technique emerges as a promising applicant for AM in LIBs, and the arc-discharge technique provides an alternative way for synthesizing other transition metal sulfides supported on carbonaceous materials.

Oxidation-induced graded bandgap narrowing in Two-dimensional tin sulfide for high-sensitivity broadband photodetection.

Two-dimensional (2D) layered group-IV monochalcogenides with large surface-to-volume ratio and high surface activity make that their structural and optoelectronic properties are sensitive to air oxidation. Here, we report the utilization of oxidation-induced gradient doping to modulate electronic structures and optoelectronic properties of 2D group-IV monochalcogenides by using SnS nanoplates grown by physical vapor deposition as a model system. By a precise control of oxidation time and temperature, the structural transition from SnS to SnSOx could be driven by the layer-by-layer oxygen doping and intercalation. The resulting SnSOx with a graded narrowing bandgap exhibits the enhanced optical absorption and photocurrent, leading to the fabricated SnSOx photodetector with remarkable photoresponsivity and fast response speed (<64 µs) at a broadband spectrum range of 520-1550 nm. The peak responsivity (7294 A/W) and detectivity (9.54 × 109 Jones) of SnSOx device are at least two orders of magnitude larger than those of SnS photodetector. Moreover, its photodetection performance can be competed with state-of-the-art of 2D materials-based photodetectors. This work suggests that the air oxidation could be utilized as an efficient strategy to engineer the electronic and optical properties of SnS and other 2D group-IV monochalcogenides for the development of high-performance broadband photodetectors.