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Metal Sulfide Photocatalysis: Visible-Light-Induced Organic Transformations
摘要： Transition-metal sulfides belong to an important subgroup of semiconductor photocatalysts that could promote a variety of valuable redox reactions under mild conditions. One notable merit of metal sulfides is their relatively smaller bandgaps than metal oxides, which in turn make sure that many of them can directly utilize visible light. Historically, the deployment of metal sulfides for visible-light-induced organic transformations took place shortly after the genesis of the research field of heterogeneous photocatalysis. In this review, we primarily focus on recent state-of-the-art advancements of metal sulfide photocatalysis aimed at visible-light-induced selective organic transformations. Interests in this specific branch of photocatalysis have been rekindled due to the new methods for materials synthesis; the pursuit of new mechanisms; or the integration of metal sulfides with metal oxides, metal nanoparticles or other emerging materials. Thus we categorize them into four sections according to the different strategies in developing novel or more efficient organic processes. Binary and ternary metal sulfides, usually associated with new materials synthesis and mechanistic insights, can be used directly for visible-light-induced organic transformations. This is the basis of other further developments and will be introduced firstly. Next, the cooperation between metal sulfides and metal oxides or metal nanoparticles can be conducive to many photocatalytic systems. These developments will be discussed in the next two ensuing sections. Furthermore, the integration of metal sulfides with recent developed emerging materials such as metal-organic frameworks (MOFs), graphene and graphitic carbon nitride (g-C3N4) would be discussed in another section to highlight the importance of merging metal sulfides with these materials. We attempt to keep an impartial panorama of these four distinctive sections even though the phases of development are quite different among sections, leaving plenty of room for the future expansion of this burgeoning area.
关键词： Metal Sulfide,Selective Oxidation,Photocatalysis,Visible Light,Selective Reduction
更新于2025-09-23 15:23:52
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Chip-Scale Molecular Clock
摘要： An ultra-stable time-keeping device is presented, which locks its output clock frequency to the rotational-mode transition of polar gaseous molecules. Based on a high-precision spectrometer in the sub-terahertz (THz) range, our new clocking scheme realizes not only fully electronic operation but also implementations using mainstream CMOS technology. Meanwhile, the small wavelength of probing wave and high absorption intensity of our adopted molecules (carbonyl sulfide, 16O12C32S) also enable miniaturization of the gas cell. All these result in an 'atomic-clock-grade' frequency reference with small size, power, and cost. This paper provides the architectural and chip-design details of the first proof-of-concept molecular clock using a 65-nm CMOS bulk technology. Using a 231.061-GHz phase-locked loop (PLL) with frequency-shift keying (FSK) modulation and a sub-THz FET detector with integrated lock-in function, the chip probes the accurate transition frequency of carbonyl sulfide (OCS) gas inside a single-mode waveguide, and accordingly adjusts the 80-MHz output of a crystal oscillator. The clock consumes only 66 mW of dc power and has a measured Allan deviation of 3.8 × 10^{-10} at an averaging time of τ = 1000 s.
关键词： CMOS,molecular clock,rotational spectroscopy,Allan deviation,GPS,carbonyl sulfide (OCS),frequency stability,navigation
更新于2025-09-23 15:23:52
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Tailoring Shape and Crystallographic Phase of Copper Sulfide Nanostructures Using Novel Thiourea Complexes as Single Source Precursors
摘要： Copper sulfide thin films and nanoparticles have been prepared via aerosol assisted chemical vapour deposition and solvothermal hot injection routes, respectively. Both routes employed heterocyclic amine based benzoylthioureato-copper(II) complexes as single source precursors. Copper sulfide thin films of diverse morphologies ranging from cubic to snowy or irregular crystallites depending on the deposition temperature were observed. Powder X-ray diffraction studies of the as deposited thin films have indicated the formation of hexagonal and cubic phases of copper sulfide. In the case of the nanoparticles, Roxbyite (Cu1.75S) phase was obtained in dodecanethiol at temperatures of 150, 190 and 230 °C. However, a preferred growth of nanoparticles was observed in the presence of oleylamine whereas the roxbyite phase was obtained at temperatures of 150, 200 and 250 °C. Also transmission electron microscopy showed the formation of close to spherical, hexagonal nano-disk and rod shaped nanoparticles.
关键词： Aerosol assisted chemical vapour deposition,Nanoparticles,Heterocyclic thiourea,Copper sulfide,Thermolysis,Thin films
更新于2025-09-23 15:23:52
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Bismuth Sulfide Nanorods with Retractable Zinc Protoporphyrin Molecules for Suppressing Innate Antioxidant Defense System and Strengthening Phototherapeutic Effects
摘要： Bismuth (Bi)-based nanomaterials (NMs) are widely used for computed tomography (CT) imaging guided photothermal therapy, however, the photodynamic property is hardly exhibited by these NMs due to the fast electron–hole recombination within their narrow bandgap. Herein, a sophisticated nanosystem is designed to endow bismuth sulfide (Bi2S3) nanorods (NRs) with potent photodynamic property. Zinc protoporphyrin IX (ZP) is linked to Bi2S3 NRs through a thermoresponsive polymer to form BPZP nanosystems. The stretching ZP could prebind to the active site of heme oxygenase-1 overexpressed in cancer cells, suppressing the cellular antioxidant defense capability. Upon NIR laser irradiation, the heat released from Bi2S3 NRs could retract the polymer and drive ZP to the proximity of Bi2S3 NRs, facilitating an efficient electron–hole separation in ZP and Bi2S3 NRs, and leading to reactive oxygen species generation. In vitro and in vivo studies demonstrate the promising photodynamic property of BPZP, together with their photothermal and CT imaging performance.
关键词： photodynamic therapy,heme oxygenase-1,bismuth sulfide,near-infrared,zinc protoporphyrin IX
更新于2025-09-23 15:23:52
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A novel “turn-on” mitochondria-targeting near-infrared fluorescent probe for determination and bioimaging cellular hydrogen sulfide
摘要： Hydrogen sulfide (H2S) has been regarded as an important gas transmitter playing vital role in cytoprotective processes and redox signaling. It is very meaningful to monitor and analyze it in biosystem for obtaining important physiological and pathological information. Despite numerous fluorescent probes for cellular H2S have been reported in past decades, only a few have capability to detect mitochondrial H2S with near-infrared (NIR) emission. Therefore, a new mitochondria-targeting NIR fluorescent probe (Mito-NSH) for detection of cellular H2S was developed by introducing 2,4-dinitrophenyl ether into a novel dye (Mito-NOH). A large "turn-on" NIR fluorescence response was obtained due to thiolysis of ether to hydroxyl group when Mito-NSH was treated with NaHS. Moreover, Mito-NSH could quantitatively detect H2S at concentration ranging from 0 to 30 μM with a detection limit of 68.2 nM, and it exerts some superior optical properties, such as large stokes shift (107 nm), highly selectively mitochondria location, fast response and high selectivity to H2S. More impressively, it was successfully applied to imaging exogenous and endogenously generated H2S in living HeLa cells via confocal fluorescence microscopy.
关键词： Fast response,NIR fluorescent probe,"Turn-on" response,Hydrogen sulfide,Mitochondria-targeting
更新于2025-09-23 15:23:52
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Tunable Wide-Bandwidth Resonators Based on Layered Gallium Sulfide
摘要： Wide-bandwidth and high-frequency operation are the two desired properties from resonators in a wide range of applications, such as communication devices, energy harvesters, inertial sensors, and electronic components. However, achieving both of these prerequisites along with detectable vibration amplitudes is very challenging. Herein, nano-electromechanical resonators based on layered gallium sulfide (GaS) are demonstrated. These resonators show resonance frequencies in the range of 10–25 MHz under ambient conditions and a bandwidth of hundreds of kilohertz, which can be simply tuned by predetermining the dimensions of the devices. Therefore, this study emphasizes that, in addition to excellent performances in electronic and optoelectronic applications, GaS can also be implemented as a high performance core element in nanoresonator applications.
关键词： electromechanical properties,wide-bandwidth resonators,gallium sulfide,2D materials
更新于2025-09-23 15:23:52
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Optical and photoconductive properties of indium sulfide fluoride thin films
摘要： This work reports on transparent semiconducting indium sulfide fluoride (ISF) thin-films exhibiting high sensitivity to ultraviolet radiation. The films were deposited on fused silica and silicon substrates using a radio-frequency plasma-enhanced reactive thermal evaporation system. The deposition was performed evaporating pure indium in SF6 plasma at a substrate temperature of 423 K. Rutherford backscattering measurements were used to determine the chemical composition of the films deposited on silicon substrates. The surface morphology was studied using scanning electron microscopy technique. The film characterization includes electrical, optical, and photoconductivity measurements. The synthesized compound is highly-resistive (~700 MΩ-cm at 300 K) and exhibits an evident semiconducting behavior. The activation energy of 0.88 eV is deduced from the temperature dependence of electrical resistivity. The indirect band energy gap of 2.8 eV is determined from transmittance spectra of the ISF films. The photoconductivity band is centered at 345 nm wavelength. The photoconductivity spectrum also shows the Urbach tail with a characteristic energy of 166 meV. ISF is a promising candidate for a buffer layer in chalcogenide-based solar cells.
关键词： Thin-films,Indium sulfide fluoride,Optical properties,Photoconductivity,Photovoltaics,Amorphous semiconductors
更新于2025-09-23 15:23:52
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Effect of Na doping on structural and optical properties in Cu2ZnSnS4 thin films synthesized by thermal evaporation method
摘要： Quaternary chalcogenide Cu2ZnSnS4 (CZTS) compound, a potential material for application as absorber layer in thin film solar cells, is synthesized by direct melting of the constituent elements taken in stoichiometry compositions. Alkali element Na was incorporated into CZTS thin films synthesized by thermal evaporation method, in order to further improve the structural and optical properties. X-Ray diffraction (XRD), Raman spectroscopy, Energy dispersive spectrometry and optical spectrophotometry were used to characterise the phase purity and optical properties. It showed that the diffusion of Na ions is uniform in the films after annealing. XRD analysis showed that CZTS films possess polycrystalline structure with [221] preferred orientation. Na ions incorporation in CZTS thin films could improve the cristallinity, the graine size and the absorption coefficient. For CZTS: Na 5%, optical results revealed higher absorption coefficient (>105 cm-1) and direct optical band gap of 1.56 eV with p-type conductivity.
关键词： Semiconductors,Sodium doping,Structural properties,Optical properties,Copper zinc tin sulfide,Thin films,Thermal evaporation
更新于2025-09-23 15:23:52
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Construction of a Novel Fluorescent Probe for On-site Measuring Hydrogen Sulfide Levels in Food Samples
摘要： Hydrogen sulfide (H2S) has been involved in many foodstuffs and beverages. On-site measuring the H2S level in food samples was beneficial to the concerns about food safety and food quality. Herein, we rationally constructed a novel fluorescent probe to track the H2S levels in various food samples. The optical experiments indicated that the probe displayed highly selective and sensitive response to H2S. In addition, the probe can function well in a wide pH value condition, providing a reliable platform to sense H2S. The practical application demonstrated that the probe was applied for tracking H2S levels in banana, grape, and vinegar for the first time. Importantly, by fabricating test strips, the probe was first served to monitor the released H2S in raw meat without relying on elaborate instrumentation. Thus, the probe could be employed as a simple tool to measure the H2S levels in various food samples, as well as to monitor the fresh-like quality of raw meat under on-site conditions.
关键词： Fluorescent probe,On-site measurement,Hydrogen sulfide,Food sample,Test strip
更新于2025-09-23 15:23:52
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Facet-Dependent Photocatalytic Behaviors of ZnS-Decorated Cu <sub/>2</sub> O Polyhedra Arising from Tunable Interfacial Band Alignment
摘要： ZnS particles were grown over Cu2O cubes, octahedra, and rhombic dodecahedra for examination of their facet-dependent photocatalytic behaviors. After ZnS growth, Cu2O cubes stay photocatalytically inactive. ZnS-decorated Cu2O octahedra show enhanced photocatalytic activity resulting from better charge carrier separation upon photoexcitation. Surprisingly, Cu2O rhombic dodecahedra give greatly suppressed photocatalytic activity after ZnS deposition. Electron paramagnetic resonance (EPR) spectra agree with these experimental observations. Time-resolved photoluminescence (TRPL) profiles provide charge transfer insights. The decrease in the photocatalytic activity is attributed to an unfavorable band alignment caused by significant band bending within the Cu2O (110)/ZnS (200) plane interface. A modified Cu2O–ZnS band diagram is presented. Density functional theory (DFT) calculations generating plane-specific band energy diagrams of Cu2O and ZnS match well with the experimental results, showing charge transfer across the Cu2O (110)/ZnS (200) plane interface would not happen. This example further illustrates that the actual photocatalysis outcome for semiconductor heterojunctions cannot be assumed because interfacial charge transfer is strongly facet-dependent.
关键词： interfacial charge transfer,zinc sulfide,cuprous oxide,facet-dependent properties,heterojunctions,band alignment
更新于2025-09-23 15:23:52