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Improved formaldehyde gas sensing properties of well-controlled Au nanoparticle-decorated In2O3 nanofibers integrated on low power MEMS platform
摘要： Approaches for the fabrication of a low power-operable formaldehyde (HCHO) gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide (In2O3) nanofibers decorated with well-dispersed Au nanoparticles as a sensing material. Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process. Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers. The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes. The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system (MEMS) technique. The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity. The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration, the size of the adsorbed Au nanoparticles, the applied power to raise the temperature of a sensing part and the kind of target gases.
关键词： Formaldehyde,Gold nanoparticle,In2O3 nanofiber,Gas sensor,Micro-platform,Low power
更新于2025-09-12 10:27:22
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An Electrode Design Rule for Organic Photovoltaics Elucidated Using a Low Surface Area Electrode
摘要： It is widely considered that charge carrier extraction in bulk-heterojunction organic photovoltaics (BHJ OPVs) is most efficient when the area of contact between the semiconductor layers and the electrodes is maximized and the electrodes are electrically homogeneous. Herein, it is shown that ≈99% of the electrode surface can in fact be insulating without degrading the efficiency of charge carrier extraction, provided the spacing of the conducting areas is less than or equal to twice the optimal thickness of the BHJ layer. This striking result is demonstrated for BHJ OPVs with both conventional and inverted device architectures using two different types of BHJ OPVs, namely, PCDTBT:PC70BM and the ternary blend PBDB-T:ITIC-m:PC70BM. This finding opens the door to the use of a large pallet of materials for optical spacers and charge transport layers, based on a low density of conducting particles embedded in a wide bandgap insulating matrix.
关键词： nanoparticle electrode,organic photovoltaic,gold nanoparticle,transparent electrode,polymer solar cell,organic solar cell
更新于2025-09-11 14:15:04
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Plasmonic photothermal heating of gold nanostars in a real-size container: multiscale modelling and experimental study
摘要： The ability of noble metal nanoparticles (NPs) to convert light into heat has triggered a lot of scientific interest due to the numerous potential applications, including, e.g. photothermal therapy or laser-based nanopatterning. In order for such applications to be practically implemented, the heating behaviour of NPs embedded in their surrounding medium has to be thoroughly understood, and theoretical models capable of predicting this behaviour must be developed. Here we propose a multiscale approach for modelling the photothermal response of a large ensemble of nanoparticles contained within a cm-scale, real size container. Electromagnetic field, ray tracing and heat transfer simulations are combined in order to model the response of and analyzing the heating efficiency and temperature dynamics upon laser irradiation of nanostars and nanospheres suspensions contained within a common Eppendorf tube. To validate the model, gold nanostars are then synthesised and characterized by electron microscopy and optical spectroscopy. Laser-induced heating experiments are conducted by irradiating colloid-filled Eppendorf tubes with a 785 nm continuous wave laser and monitoring by a thermographic camera. The experimental results confirm that the proposed model has potential for predicting plasmonic nanoparticle suspensions in real-scale containers, at cm3 volumes.
关键词： multiscale model,gold nanoparticle,photothermal effect,gold nanostar,surface plasmon
更新于2025-09-11 14:15:04
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Overall water splitting and hydrogen peroxide synthesis by gold nanoparticle-based plasmonic photocatalysts
摘要： Gold nanoparticle-based plasmonic photocatalysts can be driven by excitation of the localized surface plasmon resonance. Among them, hot-electron transfer-type photocatalysts have recently attracted interest as promising solar-to-chemical converters owing to the wide spectral response from visible-to-infrared light. This Minireview highlights recent studies on two kinds of artificial photosynthesis - water splitting and H2O2 synthesis from water and oxygen - using hot-electron transfer-type plasmonic photocatalysts with particular emphasis placed on the electrocatalysis of Au nanoparticles.
关键词： water splitting,gold nanoparticle,hot-electron transfer,hydrogen peroxide synthesis,plasmonic photocatalysts
更新于2025-09-11 14:15:04
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Effect of Hot-Electron Injection on the Excited-State Dynamics of a Hybrid Plasmonic System Containing Poly(3-hexylthiophene)-Coated Gold Nanoparticles
摘要： We investigated the photophysical interaction between a conjugated polymer (CP) and a plasmonic gold nanoparticle (Au NP) using transient absorption spectroscopy. We prepared a hybrid system containing CP-stabilized Au NPs by reducing a Au precursor directly with a thiol-terminated poly(3-hexylthiophene) surfactant (P3HT-SH), with the unreacted P3HT-SH chains used as an organic matrix. The P3HT attached to the Au NPs plays two critical roles in our hybrid system: it suppresses exciton quenching from the P3HT matrix to Au NPs (the spacer role) and relays hot electrons induced by surface plasmon resonance of Au NPs to P3HT (the bridge role). Thus, singlet excitons are more slowly relaxed in our hybrid system than those in a neat P3HT film. Our findings may provide important information for development of the high-efficiency hybrid optoelectronic devices.
关键词： surface plasmon resonance,transient absorption spectroscopy,conjugated polymer,photophysical interaction,plasmonic gold nanoparticle,optoelectronic devices,hot-electron injection
更新于2025-09-11 14:15:04
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Colloidal Capsules Assembled from Gold Nanoparticles Using Small-Molecule Hydrophobic Cross-linkers
摘要： Colloidal capsules (or colloidosomes) have been studied for various applications such as therapeutic agent encapsulation, photothermal therapy, imaging, and energy storage. Emulsion-based synthesis is the most common approach to preparing colloidal capsules as it is relatively straightforward and scalable. However, while the initial formation requires only introducing the colloidal subunits into an emulsion and letting them assemble at the interface, a second step is required in order to prepare stable, covalently linked colloidal capsules and preparing sub-micron colloidal capsules is quite challenging. Here we describe a simple and quick one-step method to synthesize covalently linked, stable nanoscale colloidal capsules consisting of gold nanoparticles (AuNP) and thiol-containing crosslinkers. Gold nanoparticle capsules (AuNCs) were formed by coating emulsion droplets containing thiol-containing crosslinkers with citrate-stabilized AuNPs. The physicochemical properties of the colloidal capsules can be tailored by changing the building blocks. In order to demonstrate this, colloidal capsules were assembled from AuNPs ranging from 5 nm to 20 nm in size. The use of the larger 20 nm starting particles resulted in AuNCs with a sufficiently pronounced red shift for λmax to be suitable for biological photothermal applications, where use of a NIR laser is strongly preferred. The AuNCs were found to be biocompatible and stable in cell culture condition and to provide moderate heating. This demonstrates the modularity of the synthesis and the potential advantages of a one-step synthesis to prepare nanoscale gold colloidal capsules.
关键词： Colloidal Capsules,photothermal,Colloidosomes,Gold nanoparticle capsules
更新于2025-09-11 14:15:04
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Effect of carbon nanotubes and carbon nanotubes - gold nanoparticles composite on the photocatalytic activity of TiO <sub/>2</sub> and TiO <sub/>2</sub> -SiO <sub/>2</sub>
摘要： Carbon nanotube (CNT) - gold (Au) nanoparticle (NP) nanocomposite was synthesized by simultaneously reducing the Au ions and depositing Au NPs on the surface of CNT. The functional groups were investigated with FT-IR spectra. From the Raman spectra, D-band and G-band of CNT were identified. As a result, the deposition of nanometer-sized Au NPs on the CNT sites was observed from the transmission electron microscope (TEM) images. The photodegradation of methylene blue (MB) in aqueous solutions was studied using various photocatalysts, including TiO2, TiO2-SiO2, CNT/TiO2, CNT/TiO2-SiO2, Au/TiO2, CNT-Au/TiO2 and CNT-Au/TiO2-SiO2 composites. The CNT addition (2%) leads to a synergic effect, improving the photoactivity of the catalysts. A possible physically-based mechanism was proposed involving the reduction of electron-hole recombination and fast electron-transfer possibility.
关键词： Gold nanoparticle,TiO2-SiO2,TiO2,Carbon nanotube,nano-photocatalysts
更新于2025-09-10 09:29:36
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Surface plasmon resonance of gold nanoparticles as a colorimetric sensor for indirect detection of Cefixime
摘要： This study reports a colorimetric sensor with excellent sensitivity to detect Cefixime base on gold nanoparticles. Cefixime is an antibiotic which has a wide range of applications in medicine. Cefixime did not change the surface plasmon resonance bond in gold nanoparticles solution; therefore, there was no change in the color solution of gold nanoparticles. The presence of Alizarin Red S in the system was necessary for the degradation of Cefixime, resulting in the aggregation of gold nanoparticles and a color change from red to blue. As a result of aggregation, the localized surface plasmon resonance band of gold nanoparticles decreased to around 525 nm and a new red-shifted band at 640 nm appeared which increases gradually as the function of Cefixime concentration. A unique detection limit (2.5 ng mL-1) was achieved for Cefixime in comparison with other colorimetric methods. Relative standard deviations (RSD) for 40.0 and 140.0 ng mL-1 of Cefixime were 2.6 and 1.8% for intra–day respectively. A possible mechanism was discussed for the surface plasmon resonance changes of AuNPs in the presence of Cefixime. The proposed method was applied to detect Cefixime in pharmaceutical samples with satisfactory results. This system is low-cost and is highly sensitive with no need for any preconcentration steps or using any expensive or sophisticated instrumentation.
关键词： gold nanoparticle,Cefixime,spectrometric method,surface plasmon resonance
更新于2025-09-10 09:29:36
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Light-triggered Covalent Assembly of Gold Nanoparticles for Cancer Cell Photothermal Therapy
摘要： Manipulating the assembly of gold nanoparticles (AuNPs) for maximizing the photothermal effect is a promising strategy for cancer therapy. Herein, taking advantage of the well-known tetrazole/alkene photo-click chemistry, we first demonstrated that small AuNPs (23 nm) decorated with both 2,5-diphenyltetrazole and methacrylic acid on the surface could form covalently cross-linked aggregates upon laser irradiation (λ = 405 nm). The in vitro studies indicated that the light-triggered assembling remarkably shifted the surface plasmon resonance of AuNPs to near-infrared (NIR) regions, which in consequence effectively enhanced the efficacy of photothermal therapy for 4T1 breast cancer cells. We thus believe that this new light-triggered assembly approach may offer a valuable tool for cancer treatment.
关键词： photothermal therapy,cancer cell,photo-crosslinking,gold nanoparticle,self-assembly
更新于2025-09-10 09:29:36
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Sensitive and Reproducible Gold SERS Sensor Based on Interference Lithography and Electrophoretic Deposition
摘要： Surface-enhanced Raman spectroscopy (SERS) is a promising analytical tool due to its label-free detection ability and superior sensitivity, which enable the detection of single molecules. Since its sensitivity is highly dependent on localized surface plasmon resonance, various methods have been applied for electric ?eld-enhanced metal nanostructures. Despite the intensive research on practical applications of SERS, fabricating a sensitive and reproducible SERS sensor using a simple and low-cost process remains a challenge. Here, we report a simple strategy to produce a large-scale gold nanoparticle array based on laser interference lithography and the electrophoretic deposition of gold nanoparticles, generated through a pulsed laser ablation in liquid process. The fabricated gold nanoparticle array produced a sensitive, reproducible SERS signal, which allowed Rhodamine 6G to be detected at a concentration as low as 10?8 M, with an enhancement factor of 1.25 × 105. This advantageous fabrication strategy is expected to enable practical SERS applications.
关键词： laser interference lithography,electrophoretic deposition,gold nanoparticle array,surface enhanced Raman spectroscopy,pulsed laser ablation in liquid
更新于2025-09-10 09:29:36