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plasmon resonance nanoparticles

Xuezhi Ma, Yangzhi Zhu, Ning Yu, Sanggon Kim, Qiushi Liu, Leonard Apontti, Da Xu, Ruoxue Yan, Ming Liu
The tip-enhanced Raman spectroscopy (TERS) imaging technique is designed to provide correlated morphological and chemical information with a nanoscale spatial resolution by utilizing the plasmonic resonance supported by metallic nanostructures at the tip apex of a scanning probe. However, limited by the scattering cross-sections of these nanostructures, only a small fraction of the incident light can be coupled to the plasmonic resonance to generate Raman signals. The uncoupled light then directly excites background spectra with a diffraction-limited resolution, which becomes the background noise that often blurs the TERS image...
December 4, 2018: Nano Letters
Didier Stiévenard, David Guérin, Stéphane Lenfant, Gaëtan Lévêque, Christian A Nijhuis, Dominique Vuillaume
We use a network of molecularly linked gold nanoparticles (NPSAN: nanoparticle self-assembled network) to demonstrate the electrical detection (conductance variation) of plasmon-induced isomerization (PII) of azobenzene derivatives (azobenzene bithiophene: AzBT). We show that PII is more efficient in a 3D-like NPSAN (cluster-NPSAN) than in a purely two-dimensional NPSAN (i.e., a monolayer of AzBT functionalized Au NPs). By comparison with the usual optical (UV-visible light) isomerization of AzBT, PII shows faster (a factor > ∼10) isomerization kinetics...
December 4, 2018: Nanoscale
A Asha Madhavan, S Juneja, P Sen, R Ghosh Moulick, J Bhattacharya
Protein glycation is a major biochemical event that takes place in the plasma of diabetic patients due to increased sugar levels. Extensive glycation leads to the formation of advanced glycation end products (AGEs) that is well known for having detrimental effects on diabetic patients. In the current work, we have glycated the physiologically important protein Haemoglobin A0 in vitro to study AGE formation and activity by using them as a template for gold nanoparticle (GNPs) synthesis. It was found that the surface plasmon resonance of synthesised GNPs showed high correlation with the extent of glycation...
December 4, 2018: Nanoscale Research Letters
Dong Su, Shenglin Jiang, Muni Yu, Guangzu Zhang, Huan Liu, Ming-Yu Li
The resonantly enhanced near-surface electromagnetic field of Al nanostructures (NSs) excited with UV light offers an effective and precise approach to obtain vibration information in complex mixtures up to a single-molecule magnitude. In this work, we propose a facile, cost-effective and large-scale way to fabricate self-assembled Al NSs with systematically controllable configuration and size for the preparation of SERS substrates. The stalagmite-shaped Al nanoparticles (NPs) are directly utilized based on the Volmer-Weber model and drastically develop as a function of the annealing temperature with tunable optical properties, resulting in a maximum enhancement factor of the vibrational Raman signal from adenine molecules up to 3...
December 4, 2018: Nanoscale
Kandasamy Saravanakumar, Sabarathinam Shanmugam, Nipun Babu Varukattu, Davoodbasha MubarakAli, Kandasamy Kathiresan, Myeong-Hyeon Wang
In this report, copper oxide nanoparticles (TA-CuO NPs) were synthesized using cell-free extract of Trichoderma asperellum and assessed their photothermal induced anticancerous activity. The fungal mediated TA-CuO NPs was confirmed by the surface plasmon resonance at 285-295 nm. The amide (CO) and aromatic (CC) groups in secondary metabolites of the extract was found to be an encapsulating or reducing agents for TA-CuO NPs, as indicated by IR spectra. Crystalline nature by cubic face-centered structure of the TA-CuO NPs was confirmed by XRD and their size ranges from 10 to 190 nm and an average of 110 nm by particle size analyzer (PSA)...
November 24, 2018: Journal of Photochemistry and Photobiology. B, Biology
Ankit Bisht, Jorge Cuadra, Martin Wersäll, Adriana Canales, Tomasz J Antosiewicz, Timur Shegai
Polaritons are compositional light-matter quasiparticles that arise as a result of strong coupling between a vacuum field of a resonant optical cavity and electronic excitations in quantum emitters. Reaching such a regime is often hard, as it requires materials possessing high oscillator strengths to interact with the relevant optical mode. Two-dimensional transition metal dichalcogenides (TMDs) have recently emerged as promising candidates for realization of strong coupling regime at room temperature. However, these materials typically provide coupling strengths in the range of 10-40 meV, which may be insufficient for reaching strong coupling with low quality factor resonators...
November 30, 2018: Nano Letters
Song Yi Moon, Hee Chan Song, Eun Heui Gwag, Ievgen I Nedrygailov, Changhwan Lee, Jeong Jin Kim, Won Hui Doh, Jeong Young Park
The use of hot carriers generated from the decay of localized surface plasmon resonance in noble metal nanoparticles is a promising concept for photocatalysis. Here, we report the enhancement of photocatalytic activity by the flow of hot electrons on TiO2 nanotube arrays decorated with 5-30 nm Au nanoparticles as photoanodes for photoelectrochemical water splitting. This enhanced photocatalytic activity is correlated to the size of the Au nanoparticles, where higher oxygen evolution was observed on the smaller nanoparticles...
November 28, 2018: Nanoscale
Huiling Duan, Rongjie Chen, Yuan Zheng, Chang Xu
The excitation of localized surface plasmon at the metal nanoparticles can significantly enhance the absorption of solar energy. However, the absorption peak is sharp at the resonant frequency. To achieve a broadband absorption, the blended nanofluid formed by SiO2 /Ag nanoshells of different core size and shell thickness is employed. The blended nanofluid has a good solar absorption property, whose extinction spectrum matches the solar spectrum well. The transient temperature response of the nanofluid is simulated...
November 12, 2018: Optics Express
Richard J Hermann, Michael J Gordon
Plasmon resonances and electric field enhancements of several near-field optical antennae with plasmonic nanostructures engineered at their apices were quantitatively compared using finite difference time domain simulations. Although many probe designs have been tested experimentally, a systematic comparison of field enhancements has not been possible, due to differences in instrument configuration, reporter mechanism, excitation energy, and plasmonic materials used. For plasmonic nanostructures attached to a non-plasmonic support (e...
October 15, 2018: Optics Express
Sara Elrafei, Ishac Kandas, Nader Shehata, Effat Samir
The up-conversion process is extensively studied because of its wide variety of applications such as bioimaging, energy harvesting, and optical sensors. However, the optical conversion efficiency is still relatively low and needs to be improved. Therefore, this paper introduces a detailed study of improving the up-conversion emission efficiency through adding plasmonic metallic nanostructures to the up-conversion optical centers. Our idea is to couple the optical plasmonic resonance with the visible emission of the optical centers under IR excitation...
September 17, 2018: Optics Express
Zhenzhen Hao, Sirui Feng, Yanghua Lu, Shisheng Lin
By combining the surface plasmon enhancement technique with gating effect, a tunable blue lighting emitting diode (LED) based on graphene/Ag nanoparticles (NPs)-polymethyl methacrylate (PMMA)/graphene/p-GaN heterostructure has been achieved. The surface plasmon enhancement is introduced through spin-coating Ag nanoparticles on graphene/p-GaN heterostructure while the gating effect is demonstrated through a graphene/PMMA/graphene sandwich structure, where the top graphene layer acts as the gate electrode. Compared with initial graphene/p-GaN heterostructure LEDs, the electroluminescence (EL) emission intensity of Ag NPs/graphene/p-GaN heterostructure LEDs has been largely enhanced, attributing to the surface plasmon resonance (SPR) of Ag nanoparticles...
September 17, 2018: Optics Express
Zi He, Ji Hong Gu, Wei E I Sha, Ru Shan Chen
Metallic nanoparticles (NPs) support localized surface plasmon resonances (LSPRs), which enable to concentrate sunlight at the active layer of solar cells. However, full-wave modeling of the plasmonic solar cells faces great challenges in terms of huge computational workload and bad matrix condition. It is tremendously difficult to accurately and efficiently simulate near-field multiple scattering effects from plasmonic NPs embedded into solar cells. In this work, a preconditioned volume integral equation (VIE) is proposed to model plasmonic organic solar cells (OSCs)...
September 17, 2018: Optics Express
June Sik Hwang, Minyang Yang
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 field-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...
November 21, 2018: Sensors
Baichuan Li, Yafang Chen, Aihong Peng, Xiaomei Chen, Xi Chen
Herein, vertically aligned plate-like tungsten trioxide (VAP-WO3 ) sensitized with gold nanoparticles (AuNPs) is reported for the non-enzymatic photoelectrochemical (PEC) sensing of ethanol in liquors. For the fabrication of the novel ethanol sensor, AuNPs were electrodeposited onto fluorine-doped tin oxide (FTO), and, subsequently, VAP-WO3 was hydrothermally grown on the AuNPs/FTO surface. Owing to the localized surface plasmon resonance, as well as the good conductivity of the AuNPs, the efficiency of the light absorption and the photoelectron-hole separation of VAP-WO3 were much improved, resulting in a significant enhancement in the VAP-WO3 /AuNPs/FTO photocurrent...
November 16, 2018: Journal of Colloid and Interface Science
Kannaiyan Muthulakshmi, Chinnaiyan Uma
We tested the hypothesis that silver nanoparticles (BsAgNPs) made by Bacillus subtilis subsp. inaquosorum exhibit antibacterial and antifungal activities. The bacteria formed nanoparticles in UV-visible spectra with the peak around 430 nanometer detected by surface plasmon resonance and Lambdamax. The FTIR spectra, SEM and XRD revealed the involvement of interaction of biological moieties in the formation of crystalline cuboidal nanoparticles that were had an average size of 10-20 nm. The particles exerted dose dependent antibacterial and antifungal activities and high dose equivalent to standard antibiotics...
January 1, 2019: Frontiers in Bioscience (Elite Edition)
Weifeng Lv, Chenjie Gu, Shuwen Zeng, Jiaguang Han, Tao Jiang, Jun Zhou
Gold nanoparticles with multiple branches have attracted intensive studies for their application in sensing of low trace molecules. A large number of the merits found on the gold nanoparticles for the above applications are attributed to the strong localized surface plasmon resonance excited by the incident radiation. However, a facile and flexible way of synthesizing the multi-branch gold nanoparticles with tunable localized surface plasmon resonance frequency is still a challenge for the plasmonic research field...
November 20, 2018: Biosensors
Zahra Rostampour Fathi, M Pinar Menguc, Hakan Erturk
Intercoupling of an incident electric field in metal nanoparticles causes asymmetric distribution of surface charges, which eventuates in shifting of the surface plasmon resonance frequency. This feature can be used in tuning the surface plasmon resonance and controlling the light absorption in a desired wavelength. This work provides a theoretical study of the plasmonic properties of complex gold nanostructures on a dielectric substrate where the nanoparticles have different morphologies. For analysis, we have developed a discrete dipole approximation with surface interactions-z, which is the third version of the MATLAB-based DDA-SI toolbox...
October 20, 2018: Applied Optics
Yuqiang Xiang, Yao Zhang, Xuan Sun, Yanyan Chai, Xiangdong Xu, Yonggang Hu
A simple, rapid, inexpensive, ecofriendly, and high-throughput biological strategy for the preparation of functional microspheres on a yeast-cell platform was introduced. Microspheres prepared through the treatment of yeast cells with formaldehyde and decoating buffer exhibited excellent characteristics, such as superior mechanical strength, high sulfhydryl group content, and mesoporous structure. Au nanoparticles (NPs) easily and rapidly self-assembled onto the surfaces of the yeast-based microspheres within 5 min to form rigid yeast@Au microspheres with high monodispersity and uniformity...
November 20, 2018: ACS Applied Materials & Interfaces
Siddardha Koneti, Joel Borges, Lucian Roiban, Marco S Rodrigues, Nicolas Martin, Thierry Epicier, Filipe Vaz, Philippe Steyer
Plasmonic Au nanoparticles (AuNPs) embedded into a TiO2 dielectric matrix were analyzed by combining two-dimensional and three-dimensional electron microscopy techniques. The preparation method was reactive magnetron sputtering, followed by thermal annealing treatments at 400 and 600 °C. The goal was to assess the nanostructural characteristics and correlate them with the optical properties of the AuNPs, particularly the localized surface plasmon resonance (LSPR) behavior. High-angle annular dark field-scanning transmission electron microscopy results showed the presence of small-sized AuNPs (quantum size regime) in the as-deposited Au-TiO2 film, resulting in a negligible LSPR response...
November 28, 2018: ACS Applied Materials & Interfaces
Liang Ma, Si-Jing Ding, Da-Jie Yang
Bimetallic nanoparticles are widely used in chemical catalysis and energy conversion. Their practical performance can be better exploited through morphological control by adjusting the synthetic strategy. Herein, an aqueous phase route is used to achieve the controlled preparation of bimetallic Au/Pt and hollow Au/Pt/Au nanotriangles with tunable plasmonic properties and superior photocatalytic activity. By continuously adjusting the concentration of surfactant solution, the gradual growth orientation of Pt nanoparticles on Au nanotriangles is observed, which occurs first on the tips, then on the edges, and then on the facets...
November 19, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
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