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Effects on surface-enhanced Raman scattering from copper nanoparticles synthesized by laser ablation
摘要： In this work, we report the synthesis of Cu nanoparticles (NPs) by laser ablation technique using 532 nm and 1064 nm wavelength in ethylene glycol. The optical and morphological studies of as-prepared NP colloids were characterized using UV–Visible absorption , photoluminescence spectrometers and transmission electron microscope (TEM) techniques. Cu NPs synthesized at 532 nm and 1064 nm were spherical with an average size of 3.2 ± 0.1 nm and 4.3 ± 0.1 nm respectively. Furthermore, surface-enhanced Raman scattering (SERS) studies were performed on methylene blue (MB) using Cu NPs as SERS platform. In addition, the effects of size, shape and localized surface plasmon resonance (LSPR) of Cu NPs as well as the Raman excitation wavelength used for SERS measurement were investigated and discussed to give insight into the factors affecting their SERS enhancement factor.
关键词： enhancement factor,SERS,optical properties,Cu NPs
更新于2025-09-23 15:19:57
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Photocurrent improvement of an ultra-thin silicon solar cell using the localized surface plasmonic effect of clustering nanoparticles
摘要： The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell. Here, for the first time, spherical, conical, pyramidal, and cylindrical nanoparticles as a form of a cluster in the rear side of a thin silicon cell are simulated using finite difference time domain (FDTD) method. By calculating the optical absorption and hence the photocurrent, it is shown that the clustering of nanoparticles significantly improves them. The photocurrent enhancement is the result of the plasmonic effects of clustering the nanoparticles. For more comparison, at first, a cell with a single nanoparticle at the rear side is evaluated. Then four smaller nanoparticles are put around it to make a cluster. The photocurrents of 20.478, 23.186, 21.427, and 21.243 mA/cm2 are obtained for the cells using clustering conical, spherical, pyramidal, cylindrical NPs at the backside, respectively. These values are 13.987, 16.901, 16.507, 17.926 mA/cm2 for the cell with one conical, spherical, pyramidal, cylindrical nanoparticle at the rear side, respectively. So, clustering significantly improves the photocurrents. Finally, the distribution of the electric field and the generation rate for the proposed structures are calculated.
关键词： Clustering NPs,Localized surface plasmon resonance,light management,FDTD,Photocurrent,Plasmonic solar cell
更新于2025-09-23 15:19:57
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Selective UV Absorbance of Copper Chalcogenide Nanoparticles for Enhanced Illumination Durability in Perovskite Photovoltaics
摘要： The inherent optical and electrical properties of inorganic nanoparticles (NPs) give them high potential applicability in advanced energy devices. In this study, PEDOT:PSS was remodeled with aqueous synthesized copper-based chalcogenide NPs, and the novel properties were demonstrated. Raman spectra were used to analyze the changes in intrinsic binding of PEDOT:PSS and derive the main peak shift. X-ray diffraction spectral analysis showed that a photoactive layer stably formed on PEDOT:PSS with or without NPs. Perovskite photovoltaics (PPV) were fabricated with the remodeled PEDOT:PSS as the hole transport layer, and the electrical properties were evaluated. The charge factor and power conversion efficiency were higher in the NP-based PPVs than in the reference PEDOT:PSS devices. The charge behavior in the NP-based PPVs was investigated, and the following were identified: (1) improved device drive characteristics with photocurrent vs internal voltage, (2) tenfold increase in the hole mobility of the hole-only devices, (3) optimized efficiency in the photo-generated exciton dissociation test, and (4) improved charge transport resistance based on the impedance spectrum. The inherent optical properties of the NPs were examined in an illumination-durability test of the perovskite material without encapsulation. Under continuous light exposure, PPV in NP-based devices showed better electrical stability than in the reference devices. Field-effect scanning electron microscopy analysis indicated that perovskite particles in the NP-based samples have advanced morphological stability compared to the reference samples. Thus, integrating NPs is an efficient strategy for fabricating advanced PPVs with improved device efficiency and illumination-durability, in a more cost-effective and eco-friendly manner.
关键词： illumination durability,PEDOT:PSS modification/reforming effect,charge transport,copper-based chalcogenide NPs,perovskite photovoltaics
更新于2025-09-23 15:19:57
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Greener synthesis of zinc oxide nanoparticles using Trianthema portulacastrum extract and evaluation of its photocatalytic and biological applications
摘要： Synthesis of nanoparticles (NPs) through “green” chemistry is an exciting area of research with wide applications. Trianthema portulacastrum’s extract containing greater amount of reducing agents has been explored first time for the synthesis of ZnO-NPs that characterized with UV/Vis, XRD, FT-IR, SEM, EDX, HR-TEM and XPS. The particles of ZnO-NPs are crystalline and having the size in the range of 25-90 nm. The cell viability of ZnO-NPs was studied using Mouse pre-osteoblast cell line MC3T3-E1 sub-clone 14 cells which confirmed its biocompatibility that render for biomedical applications. The antibacterial properties were evaluated against Staphylococcus aureus and Escherichia coli which showed high potency of synthesized ZnO-NPs against these species. The antifungal activities of ZnO-NPs were screened against Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus of fungal species. The antioxidant activity of the as-synthesized NPs was also studied using DPPH (2, 2-diphenyl-1-picrylhydrazyl) substrate. The ZnO-NPs were evaluated for catalytic activity through degradation of Synozol Navy Blue-KBF textile dye using solar irradiation that causes 91% degradation of the dye in 159 minutes. Mechanistic pathways for the degradation of Synozol Navy Blue-KBF dye using ZnO-NPs were also proposed from the pattern of the degradation of the dye and the resulting by-products. The results concluded that the ZnO-NPs synthesized by green method have high biological and photocatalytic applications.
关键词： green synthesis,ZnO-NPs,Dye degradation,biological Activities,crystalline structure
更新于2025-09-19 17:15:36
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An Efficient Room Temperature Ethanol Sensor Device Based on p-n Homojunction of TiO <sub/>2</sub> Nanostructures
摘要： In this paper, an efficient room temperature ethanol sensor device based on p-n homojunction of p-TiO2 nanoparticles (NPs) and n-TiO2 nanotubes (NTs) is reported. p-TiO2 NPs were prepared by low-temperature sol–gel method and coated on n-TiO2 NTs (NPs) grown by electrochemical anodization. Field emission scanning electron microscopy and X-ray diffraction authenticated the formation of stable homojunction between p-type anatase TiO2 NPs and n-type anatase TiO2 NTs. Current–voltage characteristics of the device, in the lower voltage range (0–1.26 V) for 30 °C, followed nonlinear characteristics (Schottky). With increase in voltages (>1.26 V) and temperature (40 °C–100 °C) such nonlinear behavior moves toward more linear ones. The gas sensing performance of the homojunction device was studied at room temperature with alcohols as the test species. The device offered the maximum response magnitude of ～57% (toward ethanol) at 100 ppm with appreciably fast response time and recovery time of ～30 and ～16 s, respectively. Dramatic increase in the effective depletion region area distributed throughout the nanotubular voids and the associated localized electric filed originated from the electrostatic charge separation therein (which helps in easy dissociation of target species) is possibly responsible for such efficient room temperature sensing performance.
关键词： room temperature,Ethanol sensing,fabrication and characterization,p-TiO2 nanoparticles (NPs)/n-TiO2 nanotubes (NTs),homojunction
更新于2025-09-19 17:15:36
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Enhancing Output Power of Textured Silicon Solar Cells by Embedding Indium Plasmonic Nanoparticles in Layers within Antireflective Coating
摘要： In this study, we sought to enhance the output power and conversion efficiency of textured silicon solar cells by layering two-dimensional indium nanoparticles (In NPs) within a double-layer (SiNx/SiO2) antireflective coating (ARC) to induce plasmonic forward scattering. The plasmonic effects were characterized using Raman scattering, absorbance spectra, optical reflectance, and external quantum efficiency. We compared the optical and electrical performance of cells with and without single layers and double layers of In NPs. The conversion efficiency of the cell with a double layer of In NPs (16.97%) was higher than that of the cell with a single layer of In NPs (16.61%) and greatly exceeded that of the cell without In NPs (16.16%). We also conducted a comprehensive study on the light-trapping performance of the textured silicon solar cells with and without layers of In NPs within the double layer of ARC at angles from 0° to 75°. The total electrical output power of cells under air mass (AM) 1.5 G illumination was calculated. The application of a double layer of In NPs enabled an impressive 53.42% improvement in electrical output power (compared to the cell without NPs) thanks to the effects of plasmonic forward scattering.
关键词： textured silicon solar cells,antireflective coating (ARC),indium nanoparticles (In NPs),plasmonic forward scattering
更新于2025-09-19 17:15:36
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One-Step Synthesis of Ag@TiO2 Nanoparticles for Enhanced Photocatalytic Performance
摘要： Polyamide network polymers (PNP) modi?ed TiO2 nanoparticles (NPs) were decorated with Ag NPs in hydrothermal gel method, forming one-step synthesized photocatalysts, Ag@TiO2 NPs. The effect of PNP and the amount of Ag NPs added were investigated in this work. PNP acted as a nanocage to prevent TiO2 aggregation and capture Ag accurately, which could effectively control product sizes and improve dispersibility in solvents. Simultaneously, TiO2 NPs modi?ed with Ag NPs exhibited remarkable photocatalytic effects. One-step synthesis simpli?ed the experimental process and avoided the agglomeration of silver ions during the secondary reaction, achieving the purpose of uniform distribution at a speci?c location of TiO2 NPs. The prepared Ag@TiO2 NPs-0.5 could remove 79.49% of Methyl Orange (MO) after 3 h of ultraviolet light irradiation, which was 2.7 times higher than the reaction rate of pure TiO2 NPs. It also exhibited good photoactivity under Visible light conditions. Moreover, the mineralization rate of MO over the Ag@TiO2 NPs-0.5 could be up to 72.32% under UV light and 47.08% under Visible light irradiation, which revealed that the prepared catalysts could effectively degrade most of the MO to CO2 and H2O. The samples also demonstrated the excellent stability and easy recyclability with over 90% of the original catalytic level for MO degradation. The photocatalysts studied also exerted broad application prospects such as photovoltaic hydrogen production, electronic sensors and biomedicine.
关键词： Ag@TiO2 NPs composite,MO removal,one-step synthesis,photocatalytic
更新于2025-09-19 17:15:36
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Electroactive Au@Ag NP Assemblies Driven Signal Amplification for Ultrasensitive Chiral Recognition of D-/L-Trp
摘要： A novel ingenious and ultrasensitive chiral electrochemical transducer is proposed for the tryptophan (Trp) isomers detection by using electroactive Au@Ag NPs as electrochemical tags. Moreover, the large binding constant of D-Trp on NPs and strong interaction between D-Trp and Cu2+ cause electroactive Au@Ag NP to assembly on the electrode, generating strong differential pulse voltammetry (DPV) signals from the oxidation of Ag0 to Ag+. In sharp contrast to D-Trp, L-Trp leads to the assembly of Au@Ag NP oligomers on electrode, resulting in a weak DPV signal. The distinct DPV responses enable the developed electrochemical chiral transducer for the sensitive and accurate quantification of D-/L-Trp. The limit of detection (LOD) is 1.21 pM for D-Trp. This established electrochemical chiral sensor also achieves the specific determination of enantiomeric excess. In comparison to other reported approaches, this proposed electrochemical chiral sensor excels by its sensitivity, simplicity and good availability of electroactive Au@Ag NP assemblies. Target-induced colorimetric assays can be converted into electrochemical assays for the dual signal amplification in the field of ultrasensitive enantioselective chiral discrimination.
关键词： Au@Ag NPs,Chiral recognition,Trp enantiomers,Electroactive,Assemblies
更新于2025-09-19 17:15:36
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Alloyed Pd Ni hollow nanoparticles as cocatalyst of CdS for improved photocatalytic activity toward hydrogen production
摘要： Photocatalytic hydrogen evolution has been regarded as an efficient method for H2 production, in which the cocatalysts play a crucial role. In this work, two-dimensional (2D) snow-flake CdS was synthesized via a solvothermal method. PdeNi hollow alloy with different compositions were synthesized by a galvanic replacement method, and decorated on CdS surface. The structural microscopic and spectroscopic analysis demonstrated that the formation of PdNi hollow nanoparticles (HNPs) and the decoration of PdNi HNPs on CdS (PdNi/CdS). Photocatalytic hydrogen evolution reaction was performed under visible light irradiation (l ≥ 420 nm). Pd1Ni1/CdS exhibited higher photocatalytic H2 generation rate about 54 mmol/h/g with a quantum efficiency of 63.97% at 420 nm, which was 1.7-fold higher than that of Pd/CdS (32.4 mmol/h/g). The high photocatalytic performance for Pd1Ni1/CdS was mainly attributed to the strong interaction between Pd1Ni1 HNPs and CdS, and the formation of unique hollow structure of PdNi alloy with porous nature which provided more active sites for H2 evolution. Additionally, the synergistic effect between Pd and Ni, as well as the 2D morphology of CdS enhance the mobility of photo-generated charge carriers which minimize their recombination in turn enhance the photocurrent and photocatalytic performance of solar water splitting reaction.
关键词： PdNi hollow NPs,Hydrogen production,Photocatalyst,CdS
更新于2025-09-19 17:15:36
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Tunable Low Power Piezo-Plasmonic Random Laser under External Voltage
摘要： This study was aimed to introduce a new kind of low power and tunable random lasers based on piezo-plasmonic core/shell nanoparticles (NPs) consisting of lead zirconate titanate and gold, mixed by different concentrations of Rhodamine B (RhB) dye. To get the random lasing, the sample was exposed to pulsed laser at the presence and in the absence of an external voltage. We got a gradual increase in the thermo-plasmonic emission intensity was enhanced by decreasing the threshold lasing due to an increase in scattering, which more easily made a close loop path in the gain medium. Our results showed some spikes with the same pump energy in emission spectrum which confirmed the coherence random lasing. This phenomenon could be observed in PZT@Au NPs and it could not be observed in Au@PZT NPs in low and high concentrations. properties by increasing the applied voltage on core/shell NPs, which depended on the boundary conditions between the shell and the core samples. By external voltage, the Furthermore, in lower pump energy, we observed low peak intensity in the emission spectrum and it increased as the pump energy overrode the lasing threshold. The emission spectrum became narrow with a sharp increase in the emission intensity, which we could reach a rapid decrease in the full width at half maximum (FWHM) of the emission intensity above the threshold. These results showed the possibility of using these new kinds of materials for low threshold and controllable random lasing.
关键词： external voltage,thermo-plasmonic,piezo-plamsonic,random laser,Au@PZT,PZT@Au core/shell NPs
更新于2025-09-19 17:13:59