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Investigation of temperature and frequency dependence of electrical conductivity and dielectric behavior in CuS and rGO capped CuS nanocomposites
摘要： In this work, we develop a simple and low-cost strategy toward the one-pot synthesis of reduced graphene oxide (rGO) capped copper sulfide (CuS) nanocomposite through an obvious redox transformation reaction between Cu and graphene oxide (GO) without any additive. The prepared CuS and rGO capped CuS nanocomposite have been characterized by various physicochemical techniques for the observation of shape, morphology, and structure. It reveals the average size of the synthesized samples in the range of 10–30 nm with the hexagonal structure. The UV–vis absorption spectra exposed the strong absorption peak of CuS and rGO capped CuS composites in the range of NIR region was observed. The synthesized samples displayed high dielectric constant and electrical conductivity in a wide range of frequency (102–106 Hz). The effect of temperature on the electrical conductivity of the synthesized rGO capped CuS nanocomposite was also investigated. The excellent electrical conductivity performance is ascribed to the synergistic effect between CuS and rGO. As the temperature increases, the maximum electrical conductivity of rGO capped CuS composite was exponentially increased at high temperature. The synthesized composite with a high dielectric constant and electrical conductivity is a promising material in high capacitance, and further, it is used as electrode materials for supercapacitors and energy storage applications.
关键词： electrical conductivity,temperature effect,CuS nanocomposites,reduced graphene oxide,dielectric constant
更新于2025-11-21 11:18:25
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In Situ Microwave-Assisted Fabrication of Hierarchically Arranged Metal Sulfide Counter Electrodes to Boost Stability and Efficiency of Quantum Dot-Sensitized Solar Cells
摘要： This study describes preparation of metal sulfide counter electrodes (CEs) through one-pot microwave-assisted route to improve power conversion efficiency (PCE) of quantum dot-sensitized solar cells at a lower cost. The CuS nanorods, Ni0.96S nanoparticles, and PbS nanocubes are synthesized and deposited in situ on fluorine-doped tin oxide substrate to serve as CEs without further post-treatment. Effects of several reaction parameters including sulfur precursor (Na2S, C2H5NS, CH4N2S), Cu concentration, reaction time, and choice of cation (Cu, Ni, Pb) on the CEs morphology, electrochemical characteristics, and PCE are studied. Furthermore, nanostructure formation and thin film growth are studied and correlated with PCE, from which morphology- and composition-performance relationships can be inferred. Hierarchically assembled nanorod CuS CEs exhibit higher electrochemical stability in the S2–/Sn2– redox reaction. Together with the efficient charge transfer and higher diffusion coefficient of polysulfide redox at the electrode/electrolyte interface, deduced from electrochemical impedance spectroscopy and Tafel analyses, a PCE of 8.32% is achieved for the CuS CE. The enhanced photovoltaic performance is ascribed to the 1D CuS nanorods forming a diffusive structure which decreases charge transfer impedance and facilitates regeneration of polysulfide redox leading to a higher short-circuit current density and fill factor.
关键词： In situ deposition,quantum dot-sensitized solar cells,counter electrode,CuS,microwave-assisted synthesis
更新于2025-11-14 17:04:02
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Enhanced solar induced photo-thermal synergistic catalytic CO2 conversion by photothermal material decorated TiO2
摘要： Semiconductor material with narrow bandgap is an ideal photo-thermal conversion material because of its high absorption intensity in infrared region. Here, CuS/TiO2 composites were synthesized based on UV-responsive TiO2 compound with narrow bandgap semiconductor material CuS for CO2 conversion under full-spectrum irradiation. The experimental results showed that 2% CuS/TiO2 exhibited higher photocatalytic CO2 reduction efficiency due to the solar induced photo-thermal synergistic effect. CuS can absorb and convert infrared light into heat energy, which promotes the utilization range of sunlight for CO2 conversion. In-situ Fourier transform infrared spectroscopy (FT–IR) was used to explain the photocatalytic mechanism at the molecular level. This work suggested a feasible way for integrated utilization of solar energy by narrow bandgap semiconductor compounds with TiO2 to convert CO2.
关键词： TiO2,photocatalysis,solar,CuS,CO2 conversion
更新于2025-09-23 15:23:52
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Combustion synthesis, characterization and photocatalytic application of CuS/Bi4Ti3O12 p-n heterojunction materials towards efficient degradation of 2-methyl-4-chlorophenoxyacetic acid herbicide under visible light
摘要： In this study, a series of CuS/Bi4Ti3O12 p-n heterojunction materials were synthesized by a two-step process. Initially, the Aurivillius phase Bi4Ti3O12 (BT) was synthesized by a facile combustion route using urea as a fuel. The Bi4Ti3O12 was subsequently modified by deposition of CuS (5-20 wt%) using a hydrothermal route to prepare the heterojunction materials. The methods of synthesis and calcination temperature were important factors which influenced the morphology, particle size and phase purity of Bi4Ti3O12 material. Phase pure BT nanoplates with planar dimension of 150-200 nm and thickness between 50-70 nm were obtained at a calcination temperature of 600oC. Pure CuS prepared by hydrothermal method, contained hierarchical microspheres with diameter in the range of 1.2 to 1.6 μm. The heterostructure materials exhibited hierarchical flower like structure consisting of ultrathin CuS nanosheets and BT-nanoflakes. HRTEM and microstructural study revealed microscopic close interaction between the two phases. The optical and electrical measurement study suggested significant improvement in visible light absorption (400-800 nm) and charge carrier separation due to heterojunction formation. The CuS/Bi4Ti3O12 materials showed excellent photocatalytic activity for aqueous phase degradation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) herbicide under visible light (> 95 % degradation in 3 h). The rate constant for CuS/Bi4Ti3O12 materials was 4.5 times higher than the pure BT material towards MCPA degradation. The ?OH and O2?– radicals have been identified as the reactive species, the formation of which was confirmed by spectrometric method using terephthalic acid and nitroblue tetrazolium as molecular probes. The mechanism of MCPA degradation over the photocatalyst surface has also been elucidated using LC-ESI-MS, TOC and scavenger experiments.
关键词： photocatalysis,MCPA,CuS,Bi4Ti3O12,p-n heterojunction
更新于2025-09-23 15:22:29
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Transition metal nanohybrid as efficient and stable counter electrode for heterostructure quantum dot sensitized solar cells: A trial
摘要： Counter electrodes are critical components of third generation solar cells. A simple strategy of utilizing iso-structural analogue of graphene, namely 2D molybdenum di-sulphide as nanohybrid with CuS as counter electrode is explored in this work. Formation of heterostructure photoanode with CdSe/CdS quantum dots along with nano-hybrid counter electrode has significantly boosted current density and open circuit voltage. The designed heterostructure and the counter electrode performs exceptionally well with good stability due to synergistic effect, thus spiking new hopes in achieving high efficiency in quantum dot solar cells.
关键词： Hall effect,CuS-MoS2 nanohybrid,CdSe/CdS heterostructures,Mobility
更新于2025-09-23 15:21:01
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Effect of RF Power on the Properties of Sputtered-CuS Thin Films for Photovoltaic Applications
摘要： Copper sulfide (CuS) thin films were deposited on a glass substrate at room temperature using the radio-frequency (RF) magnetron-sputtering method at RF powers in the range of 40–100 W, and the structural and optical properties of the CuS thin film were investigated. The CuS thin films fabricated at varying deposition powers all exhibited hexagonal crystalline structures and preferred growth orientation of the (110) plane. Raman spectra revealed a primary sharp and intense peak at the 474 cm?1 frequency, and a relatively wide peak was found at 265 cm?1 frequency. In the CuS thin film deposited at an RF power of 40 W, relatively small dense particles with small void spacing formed a smooth thin-film surface. As the power increased, it was observed that grain size and grain-boundary spacing increased in order. The binding energy peaks of Cu 2p3/2 and Cu 2p1/2 were observed at 932.1 and 952.0 eV, respectively. Regardless of deposition power, the difference in the Cu2+ state binding energies for all the CuS thin films was equivalent at 19.9 eV. We observed the binding energy peaks of S 2p3/2 and S 2p1/2 corresponding to the S2? state at 162.2 and 163.2 eV, respectively. The transmittance and band-gap energy in the visible spectral range showed decreasing trends as deposition power increased. For the CuS/tin sulfide (SnS) absorber-layer-based solar cell (glass/Mo/absorber(CuS/SnS)/cadmium sulfide (CdS)/intrinsic zinc oxide (i-ZnO)/indium tin oxide (ITO)/aluminum (Al)) with a stacked structure of SnS thin films on top of the CuS layer deposited at 100 W RF power, an open-circuit voltage (Voc) of 115 mA, short circuit current density (Jsc) of 9.81 mA/cm2, fill factor (FF) of 35%, and highest power conversion efficiency (PCE) of 0.39% were recorded.
关键词： covellite,CuS/SnS absorber,CuS thin film,solar cell,RF magnetron sputtering
更新于2025-09-23 15:19:57
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Photo-chemically derived Plasmonic Semiconductor Nanocrystals as Optical Switch for Ultrafast Photonics
摘要： Establishing new photonic material with large optical nonlinearity in the near-infrared regime is significant for ultrafast optical science and devices. In this paper, we developed a facile photochemical approach to fabricate covellite CuS plasmonic nanocrystals (NCs) with high chemical stability and strong oxidation resistance under ambient conditions. The photo-chemically derived CuS NCs possess strong absorption in the visible-to-near-infrared optical range caused by the localized surface plasmon resonance effect (LSPR). We further demonstrate superior saturable absorption behavior of CuS NCs with large modulation depth and high damage threshold. By using CuS as an optical switch, a highly-stable mode-locked pulsed laser operating in the telecommunication band with signal-to-noise ratio over 70 dB and pulse duration of 1.57 ps has been achieved. Our results suggest that the photochemical method is an effective technique to fabricate plasmonic NCs, which can be developed as an excellent candidate for ultrafast photonic devices in the visible-to-near-infrared region.
关键词： Optical switch,CuS nanocrystals,Photochemical synthesis,Ultrafast photonics,Plasmonic semiconductor nanocrystals
更新于2025-09-23 15:19:57
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Magnetic Semiconductor Gd-Doping CuS Nanoparticles as Activatable Nanoprobes for Bimodal Imaging and Targeted Photothermal Therapy of Gastric Tumors
摘要： Targeted delivery of enzyme-activatable probes into cancer cells to facilitate accurate imaging and on-demand photothermal therapy (PTT) of cancers with high spatiotemporal precision promises to advance cancer diagnosis and therapy. Here, we report a tumor-targeted and matrix metalloprotease-2 (MMP-2)-activatable nanoprobe (T-MAN) formed by covalent modification of Gd-doping CuS micellar nanoparticles with cRGD and an MMP-2-cleavable fluorescent substrate. T-MAN displays a high r1 relaxivity (~60.0 mM-1s-1 per Gd3+ at 1 T) and a large near-infrared (NIR) fluorescence turn-on ratio (~185-fold) in response to MMP-2, allowing high-spatial-resolution magnetic resonance imaging (MRI) and low-background fluorescence imaging of gastric tumors as well as lymph node (LN) metastasis in living mice. Moreover, T-MAN has a high photothermal conversion efficiency (PCE, ~70.1%) under 808 nm laser irradiation, endowing it with the ability to efficiently generate heat to kill tumor cells. We demonstrate that T-MAN can accumulate preferentially in gastric tumors (~23.4% ID%/g at 12 h) after intravenous injection into mice, creating opportunities for fluorescence/MR bimodal imaging-guided PTT of subcutaneous and metastatic gastric tumors. For the first time, accurate detection and laser irradiation-initiated photothermal ablation of orthotopic gastric tumors in intraoperative mice was also achieved. This study highlights the versatility of using a combination of dual biomarker recognition (i.e., αvβ3 and MMP-2) and dual modality imaging (i.e., MRI and NIR fluorescence) to design tumor-targeting and activatable nanoprobes with improved selectivity for cancer theranostics in vivo.
关键词： molecular imaging,gastric tumor,CuS nanoparticles,activatable probe,photothermal therapy
更新于2025-09-19 17:15:36
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Electrospun CuS/PVP Nanowires and Superior Near-Infrared Filtration Efficiency for Thermal Shielding Applications
摘要： Selective filtration of near-infrared (NIR) region is of primary importance to energy saving via thermal shielding. However, uniform coating of highly effective nanomaterials on flexible substrates remains very challenging. Here, we introduce new materials processing and fabrication methodologies that manufacture electrospun copper sulfide/polyvinylpyrrolidone (CuS/PVP) nanowires for enhanced thermal shielding efficiency. Electrospinning offers well-dispersed CuS nanoparticles in a thermal shielding film, which is not achievable in typical solution coating processes. Directly deposited CuS/PVP nanowires on a flexible polymer membrane are enabled by a fluorination treatment that decreases interfacial electrostatic repulsion. Monitoring of in-situ temperature change of a box shielded, CuS/PVP nanowire film demonstrates excellent NIR shielding efficiency (87.15%). Direct integration of the film with a model car and exposure to direct sunlight demonstrates about twice-higher shielding efficiency than commercial tungsten-oxide films. Overall, the comprehensive study of nanomaterial preparation, surface treatment, and integration techniques allows to fabricate highly flexible and reliable thermal shielding films.
关键词： Near-infrared filtration,CuS/PVP nanowires,Thermal shielding,Electrospinning,and Flexible film
更新于2025-09-19 17:15:36
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Nanostructured Ni-doped CuS thin film as an efficient counter electrode material for high-performance quantum dot-sensitized solar cells
摘要： High electrocatalytic activity and low charge transfer resistance are the key factors of coutner electrodes (CEs) for high-performance quantum dot-sensitized solar cells (QDSSCs). Hence, it is challenging and highly deisrable to fabricate the CEs with high catalytic activity and low charge transfer resistance for QDSSCs. To address these issues, here, we design and prepare a new catalytic electrode by doping of nickel (Ni) ion in CuS for use as CEs in QDSSCs. The Ni-doped CuS CEs are fabricated via a facile chemcial bath deposition method. Scanning electron microscope study reveals that the Ni-doped CuS exhibits the surface morphology of nanoparticles over nanoflake structrues, while the CuS delivers the nanoflake structures. The Ni-doped CuS provides abundant active sites for reduction of polysulfide redox couple, higher electrical conductivity and offers excellent pathways for electron transfer, which yields the high electrocatalytic activity and delivers the lower charge transfer resistance at the interface of CE/electrolyte. As a result, the TiO2/CdS/CdSe QDSSCs with Ni–CuS yield a power conversion efficiency (η) of 4.36% with short circuit current density (JSC) of 13.78 mA cm?2, open-circuit voltage (VOC) of 0.567 V, and fill factor (FF) of 0.558, which are much superior to that of device with CuS CE (η = 3.24%; JSC = 10.63 mA cm?2; VOC = 0.567; FF = 0.546) under one sun illumination (AM 1.5G, 100 mW cm?2). Present work determines that Ni-doped CuS could be a promising CE material for QDSSCs due to its high electrical conductivity, excellent electrocatalytic activity, and lower charge transfer resistance.
关键词： Charge transfer resistance,Nanostructured Ni-doped CuS,Quantum dot-sensitized solar cells,Counter electrode,Electrocatalytic activity
更新于2025-09-12 10:27:22