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Photoelectrochemical performances of Fe2O3 nanotube films decorated with cadmium sulfide nanoparticles via photo deposition method
摘要： Hematite is an appropriate compound for photoelectrochemical water splitting. However, passive surface state, high recombination rate of the photo induced electron-hole pairs and poor and slow charge transfer kinetics restrict the performance of hematite. In this work, CdS/Fe2O3NTs samples have been successfully prepared by coating of CdS nanoparticles on the surface of the self-organized Fe2O3NTs via photo deposition technique in order to enhance charge separation and charge transfer kinetics. FESEM (Field Emission Scanning Electron Microscopy), XRD (X-ray diffraction), DRS (Diffraction Reflection Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) analyses have been used to characterize the CdS/Fe2O3NTs photoelectrodes obtained. CdS/Fe2O3NTs has an intense visible light absorption and displays a red-shift of the band edge in comparison with the bare Fe2O3NTs, according to DRS test. The photocurrent density of Fe2O3NTs increased approximately 5 times upon coating with CdS, as shown by photoelectrochemical measurements, indicating the significant role of the introduction of CdS in the enhancement of photo catalytic activity. CdS/Fe2O3NTs may be promising and effective photoanodes in PEC water splitting given their simple preparation and good performance.
关键词： Cadmium sulfide,Photo deposition,Fe2O3 nanotube,Photoelectrochemical water splitting
更新于2025-09-23 15:21:01
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68Ga CdTe/CdS fluorescent quantum dots for detection of tumors: investigation on the effect of nanoparticle size on stability and in vivo pharmacokinetics
摘要： Background: Quantum dots (QDs)-based theranostics offer exciting new approaches to diagnose and therapy of cancer. To take advantage of the unique properties of these fluorescent QDs for different biomedical applications, their structures, size and/or surface chemistry need to be optimized, allowing their stability and functionalities to be tailored for different biomedical applications. Methodology: Cadmium telluride/Cadmium sulfide QDs (CdTe/CdS QDs) were synthesized and their structure, size, photostability and functionalities as a bioprobe for detection of Fibrosarcoma tumors were studied and compared with Cadmium telluride (CdTe) QDs. Hence, CdTe/CdS QDs were labeled with 68Ga radionuclide for fast in vivo biological nuclear imaging. Using gamma paper chromatography (γ-PC), the physicochemical properties of the prepared labeled QDs were assessed. In vivo biodistribution and positron emission tomography (PET) imaging of the 68Ga@ CdTe/CdS QDs nanocrystals were investigated in Sprague Dawley? rats bearing Fibrosarcoma tumor. Results: CdS shell on the surface of CdTe core increases the size and photostability against high energy radiations; therefore, CdTe/CdS QDs show prolonged fluorescence as compared to CdTe QDs. Conclusion: Excellent accumulation in tumor was observed for core/shell quantum dots, but this study showed that small changes in the size of the QDs (+1 nm), after adding the CdS shell around CdTe core, greatly change their biodistribution (especially the liver uptake).
关键词： core/shell quantum dots,PET,tumor imaging,68Ga,Cadmium telluride/Cadmium sulfide
更新于2025-09-23 15:19:57
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Dielectric Measurements of Polymer Composite Based on CdS Quantum Dots in Low Density Polyethylene at Microwave Frequencies
摘要： CdS nanoparticles (NPs) as quantum dots (QDs) added into low density polyethylene (LDPE) can significantly change the MW dielectric properties of the composites. Introducing into the matrix of low density polyethylene CdS QDs increase the dielectric constant of more than twice. CdS QDs with concentration of 5 wt % to 20 wt % were prepared by the method of high-speed thermal decomposition. The size of CdS nanoparticles ranged from 2 nm to 7 nm. Experimental samples based on polymer-based nanocomposite in the form of thick films with a thickness of 80 to 100 microns were prepared by thermocompression. Complex dielectric permittivity of thick film samples was measured by T/R method from 2 to 8 GHz at room temperature (25°C). For samples with 20 wt % CdS NPs size effect was found. The change of dielectric properties of polymer composite materials is associated with the size of QDs. The dielectric constant and dielectric loss increases with decreasing size of the quantum dots. It is shown that the highest mean value of the dielectric constant and dielectric loss at a frequency range of 5 GHz to 8 GHz for cadmium sulfide nanoparticles with size of 4 nm were 12 and 189 dB/m, respectively. For QDs with ones of 6 nm average dielectric constant and dielectric loss were 5.8 and 134 dB/m, respectively. The effective dielectric constant and dielectric losses in the microwave range can be changed by CdS QDs of different sizes what consequently increases the possibility of using polymer nanocomposites as core elements of the microwave band-pass filters for various purposes.
关键词： quantum dot,cadmium sulfide,polymer composite,filled polymer,MW dielectric properties,low density polyethylene,composites
更新于2025-09-23 15:19:57
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Laser-induced graphene hybrid photoelectrode for enhanced photoelectrochemical detection of glucose
摘要： The combination of electrocatalyst with semiconductor light-absorber is of great importance to increase the efficiency of photoelectrochemical (PEC) glucose detection. Here, in-situ and synchronous fabrication of Ni-based electrocatalyst (NiEC) and CdS semiconductor in laser-induced graphene (LIG) on indium?tin oxide glass is demonstrated via a one-step laser-induced solid phase transition. A series of component and structural characterizations suggest that the laser-induced NiEC uniformly disperses in the hybrid nanocomposite and exists mainly in the form of Ni0 and NiO state. Moreover, both electrochemical and PEC investigations confirm that the as-prepared hybrid photoelectrode exhibits excellent photoelectrocatalytic ability towards glucose, which is not only attributed to the strong synergistic interaction between CdS and NiEC, but also benefited from the high conductivity as well as 3D macroporous configuration of the simultaneously formed LIG, providing the key factor to achieve sensitive non-enzymatic PEC glucose sensors. Therefore, the laser-induced hybrid photoelectrode is then applied to the PEC detection of glucose, and a low detection limit of 0.4 μM is obtained with good stability, reproducibility, and selectivity. This study provides a promising paradigm for the facile and binder-free fabrication of electrocatalyst?semiconductor?graphene hybrid photoelectrode, which will find potential applications in sensitive PEC biosensing for a broad range of analytes.
关键词： nickel electrocatalyst,hybrid nanocomposite,cadmium sulfide,photoelectrochemical sensing,laser-induced graphene,glucose
更新于2025-09-23 15:19:57
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Studying the Effect of Deposition Time on Optical Properties of CdS Thin Films
摘要： We have studied in this work the effect of deposition time on the absorption spectra and the optical energy gap of CdS thin film. That prepared by chemical bath deposition method (CBD) on glass substrate at temperature of (80 ± 5)°C. The structural features were examined by X-ray diffraction (XRD) is wurtzite structure for all samples. Transmittance spectra have been recorded in order to determine absorbance, reflectivity, absorption coefficient and the optical constants such as refractive index, extinction coefficient, real and imaginary part of dielectric constant. It was seen that all the parameters under investigation affected by deposition time (1,2 3, and 4) hours.
关键词： Cadmium sulfide,optical constants,chemical bath technique
更新于2025-09-19 17:15:36
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Nonlinear Optical Properties of CdS Semiconductor nanowires
摘要： In this work, we report on the nonlinear optical properties in single Cadmium sulfide nanowires (CdS NWs). The high qulity growth of CdS semiconductor nanowires were synthesized by chemical vapor deposition (CVD) method. The as-obtained products were characterized by X-ray diffraction (XRD) , Scanning electron microscopy (SEM), and the energy dispersive X-ray spectrom (EDS) was used to determine the specific elemental distribution and show purity of the CdS semiconductor nanowires . The excitation of femtosecond laser(800 nm, 50 fs, 80 MHz) was used to study the nonlinear optical properties of CdS nanowires, such as the Second Harmonic Generation(SHG) and optical waveguide effect. CdS NW has a second harmonic generation with a blue emission bands at a wavelength of 400 nm . Finally, based on the dark field image of the CCD taken and combined with the spectrum, it is proved that CdS NW has an optical waveguide effect.
关键词： Cadmium sulfide (CdS),Waveguide,nanowires (NWs),Second- Harmonic Generation (SHG),Chemical Vapor Deposition (CVD)
更新于2025-09-19 17:15:36
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AVALIA??O DO PAPEL DO óXIDO DE GRAFENO (GO) NA GERA??O FOTOCATALíTICA DE HIDROGêNIO EM SISTEMAS BINáRIOS (GO-CdS) E TERNáRIOS (Pt-GO-CdS)
摘要： EVALUATION OF THE GRAPHENE OXIDE (GO) ROLE IN THE PHOTOCATALYTIC GENERATION OF HYDROGEN IN BINARY (GO-CdS) AND TERNARY (Pt-GO-CdS) SYSTEMS. Water splitting is a promising process to produce hydrogen from friendly feedstock and solar energy. In this work we have evaluated binary (GO-CdS) and ternary (Pt-GO-CdS) hybrid photocatalysts for hydrogen production assisted by visible light irradiation. Cadmium sulfide and composites with GO were prepared by sonochemical and thermal methods. GO addition took place by different strategies: during the synthesis or by mechanical mixture. A variety of configurations was tested and the best performance in hydrogen production among all materials was the ternary photocatalyst named Pt(GO/CdSTT), whose hydrogen production rate was 651 μmol gcat-1 h-1. Such material was obtained by thermal method with GO addition during the synthesis. Additionally, the XRD and Raman analyses have confirmed the GO photoreduction during photocatalytic hydrogen evolution.
关键词： graphene,water splitting,cadmium sulfide,visible light,hydrogen,photocatalysis
更新于2025-09-19 17:15:36
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Carbon quantum dots implanted CdS nanosheets: Efficient visible-light-driven photocatalytic reduction of Cr(VI) under saline conditions
摘要： Chromium(VI) (Cr(VI)), a toxic metal, is generally present together with ionic salts in industrial effluents. An efficient reduction of Cr(VI) to Cr(III) in saline water is an imperative issue but still a challenging task. Literature has rarely addressed reducing Cr(VI) effectively under saline conditions. Herein, carbon quantum dots (CQDs) were successfully implanted in the CdS nanosheets (CdS-NSs) to prepare nanocomposites (i.e., CCNs) for the first time to efficiently reduce Cr(VI) to Cr(III). The newly fabricated CCNs demonstrated superior performance to reduce Cr(VI) compared to pristine CdS-NSs and CQDs-deposited CdS nanosheets (i.e., CQD/CdS-NSs) in saline water. The nanostructures were examined by spectral and photoelectrochemical measurements as well as density functional theory (DFT) calculations. Results showed that CCNs facilitated the photo-electron transport and thus suppressed charge recombination via formation of micro-regional heterostructures. A lower band gap of CCNs relative to pristine CdS-NSs and CQD/CdS-NSs extended the light absorption spectrum. The optimal photocatalyst, denoted as CCNs-2, exhibited an efficiency of ~94% for photocatalytic Cr(VI) reduction within 10 min in water containing 1200 mg/L salts. The obtained rate constant of reduction of Cr(VI) was (2.62 ± 0.04) × 10-1 min-1, approximately 4 and 3 times higher than that of pristine CdS-NSs and CQD/CdS-NSs, respectively. After 3 cycles, the CCNs-2 still showed an efficiency of ~78% aqueous Cr(VI) reduction within 10 min. Our results clearly presented that implantation relative to deposition of CQDs for CdS-NSs is a preferential strategy to enhance photocatalytic Cr(VI) reduction in saline water under visible light irradiation.
关键词： Saline water,Implantation,Photocatalytic Cr(VI) reduction,Carbon quantum dots,Cadmium sulfide nanosheets
更新于2025-09-19 17:13:59
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Performance of Graphenea??CdS Hybrid Nanocomposite Thin Film for Applications in Cu(In,Ga)Se2 Solar Cell and H2 Production
摘要： A graphene–cadmium sulfide (Gr–CdS) nanocomposite was prepared by a chemical solution method, and its material properties were characterized by several analysis techniques. The synthesized pure CdS nanoparticles (NPs) and Gr–CdS nanocomposites were confirmed to have a stoichiometric atomic ratio (Cd/S = 1:1). The Cd 3d and S 2p peaks of the Gr–CdS nanocomposite appeared at lower binding energies compared to those of the pure CdS NPs according to X‐ray photoelectron spectroscopy analyses. The formation of the Gr–CdS nanocomposite was also evidenced by the structural analysis using Raman spectroscopy and X‐ray diffraction. Transmission electron microscopy confirmed that CdS NPs were uniformly distributed on the graphene sheets. The absorption spectra of both the Gr–CdS nanocomposite and pure CdS NPs thin films showed an absorption edge at 550 nm related to the energy band gap of CdS (~2.42 eV). The Cu(In,Ga)Se2 thin film photovoltaic device with Gr–CdS nanocomposite buffer layer showed a higher electrical conversion efficiency than that with pure CdS NPs thin film buffer layer. In addition, the water splitting efficiency of the Gr–CdS nanocomposite was almost three times higher than that of pure CdS NPs.
关键词： cadmium sulfide,Gr–CdS,Cu(In, Ga)Se2,buffer layer,water splitting
更新于2025-09-19 17:13:59
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An Electrically Controlled Wavelength-Tunable Nanoribbon Laser
摘要： Nanoscale laser sources with downscaled device footprint, high energy efficiency and operation speed are pivotal for a wide array of opto-electronic and nanophotonic applications ranging from on-chip interconnects, nano-spectroscopy, sensing to optical communication. The capability of on-demand lasing output with reversible and continuous wavelength tunability over broad spectral range enables key functionalities in wavelength-division multiplexing (WDM) and finely controlled light-matter interaction, which remains an important subject under intense research. In this study, we demonstrate an electrically controlled wavelength-tunable laser based on CdS nanoribbon (NR) structure. Typical ‘S’-shaped characteristics of pump power dependence was observed for dominant lasing lines, with concomitant line width narrowing. By applying an increased bias voltage across the NR device, the lasing resonance exhibits a continuous tuning from 510 nm to 520 nm for a bias field ranged within 0 kV/cm – 15.4 kV/cm. Systematic bias-dependent absorption and time-resolved photoluminescence (PL) measurements were performed, revealing a red-shifted band edge of gain medium and prolonged PL lifetime with increased electric field over the device. Both current-induced thermal reduction of band gap and Franz-Keldysh effect were identified to account for the modification of lasing profile, with the former factor playing the leading role. Furthermore, dynamical switching of NR lasing was successfully demonstrated, yielding a modulation ratio up to ~ 21 dB. The electrically tuned wavelength-reversible CdS NR laser in this work, therefore, presents an important step towards color-selective coherent emitters for future chip-based nano-photonic and opto-electronic circuitry.
关键词： cadmium sulfide,individual nanoribbon,nanolaser,wavelength-tunable,electrical control
更新于2025-09-19 17:13:59