Core-satellite assembly of gold nanoshells on solid gold nanoparticle for color coding plasmonic nanosensor

The Analyst ◽  
2021 ◽  
Author(s):  
Nguyen Hoang Le ◽  
Nicole Cathcart ◽  
Vladimir Kitaev ◽  
Jennifer I-Ling Chen

We present core-satellite assemblies comprising solid gold nanoparticle as the core and hollow decahedral gold nanoshells as satellites for tuning the optical properties of the plasmonic structure for sensing. The...

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 359
Author(s):  
Francesco Ruffino

Bimetallic nanoparticles show novel electronic, optical, catalytic or photocatalytic properties different from those of monometallic nanoparticles and arising from the combination of the properties related to the presence of two individual metals but also from the synergy between the two metals. In this regard, bimetallic nanoparticles find applications in several technological areas ranging from energy production and storage to sensing. Often, these applications are based on optical properties of the bimetallic nanoparticles, for example, in plasmonic solar cells or in surface-enhanced Raman spectroscopy-based sensors. Hence, in these applications, the specific interaction between the bimetallic nanoparticles and the electromagnetic radiation plays the dominant role: properties as localized surface plasmon resonances and light-scattering efficiency are determined by the structure and shape of the bimetallic nanoparticles. In particular, for example, concerning core-shell bimetallic nanoparticles, the optical properties are strongly affected by the core/shell sizes ratio. On the basis of these considerations, in the present work, the Mie theory is used to analyze the light-scattering properties of bimetallic core–shell spherical nanoparticles (Au/Ag, AuPd, AuPt, CuAg, PdPt). By changing the core and shell sizes, calculations of the intensity of scattered light from these nanoparticles are reported in polar diagrams, and a comparison between the resulting scattering efficiencies is carried out so as to set a general framework useful to design light-scattering-based devices for desired applications.


2000 ◽  
Vol 122 (19) ◽  
pp. 4640-4650 ◽  
Author(s):  
James J. Storhoff ◽  
Anne A. Lazarides ◽  
Robert C. Mucic ◽  
Chad A. Mirkin ◽  
Robert L. Letsinger ◽  
...  

2016 ◽  
Vol 3 (8) ◽  
pp. 1189-1189
Author(s):  
Christian Engelbrekt ◽  
Michal Wagner ◽  
Mikkel Undall-Behrend Christiansen ◽  
Hans Erik Mølager Christensen ◽  
Xiuzhen Qian ◽  
...  

2019 ◽  
Vol 9 (2) ◽  
pp. 123
Author(s):  
Wipsar Sunu Brams Dwandaru ◽  
Fika Fauzi ◽  
Dyah Silviana Sari ◽  
Emi Kurnia Sari ◽  
Iman Santoso ◽  
...  

Carbon nanodots (Cdots) have many unique properties such as luminescence that can be utilized in various fields. The purposes of this study are to synthesize Cdots from kangkung (Ipomoea aquatica) through frying and roasting techniques and compare the optical properties of the Cdots using UV-Vis, PL, and FTIR. Three stages of synthesizing process of Cdots, i.e.: preparing the kangkung powder (root, stem, leaf) and synthesizing the Cdots through frying and roasting techniques. Each part (root, stem, and leaf) was heated in an oven at 250 oC for 2 hours and mashed into powder. The frying method was done by frying 15 g of the powder in 120 ml oil for 5 minutes at 88 oC, filtered, and dissolved in n-hexane. In addition, the roasting method was done by frying the powder without oil as much as 15 g for 5 minutes, dissolved in 120 ml of distilled water, and then filtered. The UV-Vis characterization showed one absorbance peak for Cdots via frying and roasting techniques at 293 nm to 296 nm and 262 nm to 282 nm, respectively. The Cdots through frying and roasting techniques produce red and green luminescence, respectively. The FTIR characterization showed the presence of C=C and C=O functional groups, which are the core and surface state of the Cdots by frying technique, while the samples via roasting technique showed only the core. It can be concluded that the Cdots samples obtained from frying and roasting methods have different optical properties. The frying method produces Cdots with longer wavelength at the absorbance peak in the UV-Vis test compared to the roasting method. Moreover, the frying and roasting methods produce different color luminescence.


2020 ◽  
pp. 293-324
Author(s):  
James J. Storhoff ◽  
Anne A. Lazarides ◽  
Robert C. Mucic ◽  
Chad A. Mirkin ◽  
Robert L. Letsinger ◽  
...  

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Kangwei Li ◽  
Mingming Yan ◽  
Jiandong Shen ◽  
Xin Zhang ◽  
Chunmei Geng ◽  
...  

As atmospheric fresh soot particles age, they become coated with other chemical species. This transforms their physicochemical properties and affects their optical characteristics, which is of great importance to air quality, the environment and climate change. One of the predominantly occurring states of soot particles in the ambient environment is the core-shell mixing state. In this study, we used the core-shell model to calculate the optical absorption, scattering and extinction efficiency, absorption proportion and absorption exponent of coated soot particles. We then investigated the effects of different core sizes (D0), incident wavelengths (λ), coating materials and coating thicknesses on these optical characteristics. Absorption efficiency and absorption proportion of soot particles decreased as the coating became thicker, at core sizes of D0 = 20, 50 and 100 nm and λ = 405, 532 and 781 nm, regardless of the type of coating material. As the coating thickness increased, the absorption exponent (β) of inorganic-coated soot particles tended to rise and then fall, while the β value of organic-coated soot particles kept increasing. Our results advance our scientific understanding of the interaction of optical properties with chemical composition, mixing state, and aging processes of soot particles in the atmosphere.


MRS Advances ◽  
2019 ◽  
Vol 4 (23) ◽  
pp. 1341-1347 ◽  
Author(s):  
Margaret Campbell ◽  
Paramjot Singh ◽  
Kunal Kate ◽  
Cindy K. Harnett

ABSTRACTWe demonstrate that the extrusion speed of thermoplastic urethane elastomer can modify its optical transmission by a factor of more than 100. Varying extrusion speed at constant temperature may tune optical properties along the axis of a filament, for example creating absorbent regions that are sensitive to length and diameter changes, surrounded by more transmissive segments that carry the sensor signal over long distances. Such waveguiding in a stretchable optical fiber requires a stretchable cladding with lower refractive index than the core. In experiments toward a rugged, stretchable fiber cladding, we investigated whether solvents could modify the outer structure of the filaments. Soaking the filaments in NMP (n-methyl-2-pyrrolidone), then stretching the filaments while the solvent dried, turned out to modify the filaments in a way that solvents alone did not, creating porosity and reducing the appearance of optical clarity.


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