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Effects of precursors and caustic bases on structural and vibrational properties of ZnO nanostructures elaborated by hydrothermal method
摘要： The effects of zinc ions source (zinc acetate and zinc sulfate) and caustic bases (sodium and potassium hydroxides) on structural, morphological and vibrational properties of ZnO nanostructures elaborated by simple low temperature wet chemical process are studied. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (FTIR) and Raman spectroscopies. XRD results show that ZnO structures are polycristalline hexagonal wurtzite with high crystal quality. SEM images reveal that the morphologies of the nanostructures are nanopencils except in those synthesized with zinc sulfate precursor and sodium hydroxide caustic base, where pencils agglomerate to form sand rose-like morphologies. EDAX measurements confirm the purity of the elaborated specimens by the presence of only Zn and O atoms in the samples. Raman spectroscopy studies show that the peaks, related to E2 high mode, are more intense in ZnO structures elaborated with zinc acetate when NaOH is used, and in ZnO structures elaborated with zinc sulfate when KOH is employed.
关键词： alkali hydroxides,hydrothermal synthesis,ZnO,structure,morphology,source precursor
更新于2025-09-23 15:23:52
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Electrochemical Fingerprint of CuS-Hexagonal Chemistry from (Bis(N-1,4-Phenyl-N-(4-Morpholinedithiocarbamato) Copper(II) Complexes) as Photon Absorber in Quantum-Dot/Dye-Sensitised Solar Cells
摘要： The main deficit of quantum dot/dye-sensitised solar cells (QDSSCs) remains the absence of a photosensitiser that can absorb the entire visible spectrum and increase electrocatalytic activity by enhancing the conversion efficiency of QDSSCs. This placed great emphasis on the synthesis route adopted for the preparation of the sensitiser. Herein, we report the fabrication of hexagonal copper monosulfide (CuS) nanocrystals, both hexadecylamine (HDA) capped and uncapped, through thermal decomposition by thermogravimetric analysis (TGA) and a single-source precursor route. Morphological, structural, and electrochemical instruments were used to assert the properties of both materials. The CuS/HDA photosensitiser demonstrated an appropriate lifetime and electron transfer, while the electron back reaction of CuS lowered the electron lifetime in the QDSSCs. The higher electrocatalytic activity and interfacial resistance observed from current density-voltage (I–V) results agreed with electrochemical impedance spectroscopy (EIS) results for CuS/HDA. The successful fabrication of hexagonal CuS nanostructures of interesting conversion output suggested that both HDA capped and uncapped nanocrystals could be adopted in photovoltaic cells.
关键词： photosensitiser,electrocatalystic,photovoltaic cells,single-source precursor,quantum dots
更新于2025-09-23 15:21:01
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Facile synthesis of molybdenum multisulfide composite nanorod arrays from single-source precursor for photoelectrochemical hydrogen generation
摘要： The deposition of molybdenum multisulfide thin-film photoanodes from the metal–organic precursor [CpMo(SMe)2]2 (1), at different deposition time has been investigated. Four different films were deposited at 550 °C under constant argon gas flow for 10, 15, 20, and 25 min, respectively. The surface morphology of these films analyzed with FE-SEM and AFM showed the presence of compact 1D rod-like structure of MoS2/Mo2S3 in a homogeneous form. The average diameter of the 1D compact MoS2/Mo2S3 composite nanorod arrays was found in the range of 155–298 nm deposited for different time durations. EDX analysis showed a consistency where the Mo-to-S ratio was approximately 3:4.5 and demonstrated the overall composition of the 1D MoS2/Mo2S3 composite nanorod arrays. The XRD analysis of the thin film indicated the presence of monoclinic Mo2S3 and rhombohedral MoS2 composite system. Moreover, the photocurrent density of 20 min deposited thin film is observed to be 4 mA/cm2 with highest photosensitivity of 6.78 at the overpotential of 0.3 V vs Ag/AgCl under the simulated light intensity of 100 mW/cm2 (AM 1.5G). The electrochemical impedance spectroscopy (EIS) also showed improved charge transportation with highest lifetime of the photoexcited charges in 20 min deposited thin film in comparison to the other deposition time durations. This study provides the optimized synthesis conditions for producing molybdenum-based multisulfide nanostructures and the deposition duration for their deployment in solar-based devices.
关键词： Visible light photocatalytic activity,Single-source precursor,Thin films,MoS2/Mo2S3 composite
更新于2025-09-19 17:15:36
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Electrochemical Performance of Photovoltaic Cells Using HDA Capped-SnS Nanocrystal from bis (N-1,4-Phenyl-N-Morpho-Dithiocarbamato) Sn(II) Complexes
摘要： Great consideration is placed on the choice of capping agents’ base on the proposed application, in order to cater to the particular surface, size, geometry, and functional group. Change in any of the above can influence the characteristics properties of the nanomaterials. The adoption of hexadecylamine (HDA) as a capping agent in single source precursor approach offers better quantum dots (QDs) sensitizer materials with good quantum efficiency photoluminescence and desirable particles size. Structural, morphological, and electrochemical instruments were used to evaluate the characterization and efficiency of the sensitizers. The cyclic voltammetry (CV) results display both reduction and oxidation peaks for both materials. XRD for SnS/HDA and SnS photosensitizers displays eleven peaks within the values of 27.02 for SnS in correlation to the orthorhombic structure. Current density–voltage (I–V) results for SnS/HDA exhibited a better performance compared to SnS sensitizers. Bode plot results indicate electrons lifetime (τ) for SnS/HDA photosensitizer have superiority to the SnS photosensitizer. The results connote that SnS/HDA exhibited a better performance compared to SnS sensitizers due to the presence of HDA capping agent.
关键词： photovoltaic cells,quantum dots,semiconductors,electrochemical,single-source precursor
更新于2025-09-16 10:30:52
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Synthesis of Sulfur-rich Nitrogen Dots from a Single Source Precursor and its Application in Dual-mode Sensing
摘要： In this work, a strategy of sulfur-rich doped nitrogen dots (S-Ndots) based on a single-source precursor (SSP) was developed and applied to sensing of Hg2+. Fluorescent S-Ndots were synthesized by microwave-assisted method using 2-azidothiazole as a single-source precursor, which served as carbon, nitrogen and sulfur source simultaneously. This SSP approach guarantee efficient core doping and improve the effect of doping in a molecular level, which is more efficient and simpler than the doping strategy with multiple precursors. The results showed that the as-synthesized S-Ndots have high sulfur component up to 24.6%, and their specific structure effectively promoted artificial peroxidase activity and coordination interaction. Interestingly, the fluorescence intensity could be quenched obviously and the peroxidase activity of the S-Ndots were selectively inhibited by Hg2+, then the S-Ndots were applied to the dual-mode sensing of Hg2+ with both fluorometric and colorimetric readout. The S-Ndots-based sensing assay with simplicity and rapidity showed high selectivity to Hg2+ with the detection limit of 0.1 μmol/L by fluorescence spectroscopy and a distinguishable change in the color was observed by the naked eye. In addition, the accuracy and precision were evaluated based on the quantitative detection of Hg2+ in industrial waste water samples with satisfactory results. Moreover, the S-Ndots with good biocompatibility were further explored for imaging of Hg2+ in A549 cells. As a novel member of nitrogen quantum dots family, the S-Ndots hold great promise to broaden its applications in environmental and biological sensing.
关键词： Mercury,Single-source precursor,Dual-mode sensing,Sulfur-rich doped nitrogen dots
更新于2025-09-10 09:29:36
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Direct synthesis of MoS <sub/>2</sub> or MoO <sub/>3</sub><i>via</i> thermolysis of a dialkyl dithiocarbamato molybdenum( <scp>iv</scp> ) complex
摘要： Direct synthesis of either 2H-MoS2 or a-MoO3 is made possible by thermolysis of the same single source precursor in either argon or air at moderate temperatures.
关键词： direct synthesis,thermolysis,MoS2,MoO3,single source precursor
更新于2025-09-04 15:30:14