Nanoengineering of optical resonances

Aqueous solutions containing light-absorbing nanoparticles have recently been shown to produce steam at high efficiencies upon solar illumination, even when the temperature of the bulk fluid volume remains far below its boiling point. Here we show that this phenomenon is due to a collective effect mediated by multiple light scattering from the dispersed nanoparticles. Randomly positioned nanoparticles that both scatter and absorb light are able to concentrate light energy into mesoscale volumes near the illuminated surface of the liquid. The resulting light absorption creates intense localized heating and efficient vaporization of the surrounding liquid. Light trapping-induced localized heating provides the mechanism for low-temperature light-induced steam generation and is consistent with classical heat transfer.

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“…(34,35) A detailed explanation of the synthesis of the gold nanomatryoshkas can also be found in recent literature. (28,29) …”

Section: Nanoparticle Synthesismentioning

confidence: 99%

Nanoparticles Heat through Light Localization

et al. 2014

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“…The grafting of an amine terminated silane coupling agent (APTES) to the silica surface enables the bonding with the colloidal gold particles 30 .…”

Section: Gold Seeding On the Surface Of The Silica Noanoparticlesmentioning

confidence: 99%

“…1a. 30 The procedure involves the synthesis of dielectric core materials, typically silica or polystyrene and their surface functionalization with terminal amine groups to facilitate attachment of negatively charged gold seed nanoparticles formed in a separate process. Synthesis of the silica nanoparticles with both narrow size distribution and rough surface was achieved following a two-phase regrowth procedure.…”

mentioning

confidence: 99%

“…32 The gold seeds deposited on the surface of the dielectric cores act as nucleation sites and are allowed to grow in size by further addition of gold precursors. 30 According to the mechanism and kinetics of gold crystallization, 33,34 we propose that a balance of kinetic and diffusion rates control the growth of gold nanobranches on a rough silica surface with a peak-valley pattern on which the gold seeds are evenly distributed. (Fig.…”

mentioning

confidence: 99%

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Engineering the synthesis of silica–gold nano-urchin particles using continuous synthesis

2014

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Compared to freestanding nanoparticles, supported nanostructures typically show better mechanical stability as well as ease of handling. Unique shapes such as core-shells, raspberries and crescents have been developed on supported materials to gain improved chemical and optical properties along with versatility and tunability. We report the formation of hyperbranched gold structures on silica particles, silica-gold nano-urchin (SGNU) particles. Kinetic control of crystallization, fast mass transfer as well as a bumped surface morphology of the silica particles are important factors for the growth of gold branches on the silica support. Using a microfluidic platform, continuous synthesis of SGNUs is achieved with increased reaction rate (less than 12 min. of residence time), better controllability and reproducibility than that obtained in batch synthesis. The hyper-branched gold structures display surfaceenhanced Raman scattering (SERS). Introduction.Microfluidic systems offer excellent conditions for synthesis of nanomaterials by control of mixing, temperature, and pressure combined with fast heat and mass transfer. 1, 2 Moreover, they enable controlled synthesis under higher temperature and pressure conditions than typically feasible in batch with resulting faster synthesis. 1, 3 Herein, we report batch and microfluidic synthesis of hyper-branched gold structures on silica particles, silica-gold nano-urchin (SGNU) particles. The formed particles consist of a dielectric silica core decorated with densely packed gold nanobranches stretching outward. The morphology serves as an active substrate for tip-enhanced Raman scattering, 4 and could additional have applications in catalysis and bio-imaging. 5,6 Gold nanoparticles have been synthesized by a variety of approaches for diverse applications in catalysis, bio-imaging, drug delivery and photovoltaics. Their surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) properties have been of particular interest for photothermal therapy and molecular sensing, respectively [7][8][9][10][11][12][13][14][15] . SERS active structures have been fabricated by complex with top-down methods, 4,12,16,17 but wet-chemical synthesis of gold nanoparticles offer potential advantages in simple, high yield, and limited scalable synthesis. 12,18,19,20,21,22 Gold nanostructures, such as nanorods, nanowires, tetrapods, nanoplates and star-shaped particles are particularly attractive for many applications because of their strong confinement of the electromagnetic field and high enhancement that can be tuned over a wide range of optical wave lengths in comparison with ordinary spherical structures. 11,[23][24][25][26][27] Combination of the metal nanostructure with a support material, such as in core-shells, raspberries, and crescents, affords additional advantages in tuning optical properties, improved chemical/mechanical stability, and ease of handling compared to free-standing nanoparticles.Batch methods, 20 specialized ligands 28 and additional electrochemical treat...

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“…그 작은 크기로 인해 특정 매트릭 스 내에 분산이 용이하여 전도성 접속 소재나 패키징, 전자 파 차폐 코팅, ESD(electrostatic discharge)코팅 등에 사용되 고 있다. [1][2][3][4] 반도체, LCD 및 모바일 기기산업의 급속한 성장 전망으로 인해 접속 소재의 수요 및 중요도는 증대될 것으로 예상되고 있다. 특히 휴대형 전자기기 시장이 날이 갈수록 커지고 있 어, 핵심 접속 재료인 이방성 도전필름(anisotropic conductive film)으로서 전도성 입자가 매트릭스에 분산되어있는 복합재 료(conductive particle-embedded composite material)가 주목 받고 있다.…”

Section: 서 론unclassified

Adhesion Behavior of Graphene Oxide on Spherical Polymer Particles

김신우

이상수²,

이종휘

2013

Polymer Korea

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Graphene-coated polymer particles have attracted research interests due to their emerging applications derived from their controlled structure and morphology. To control the properties of graphene oxide (GO)-polystyrene (PS) composite particles, the adsorption time and instantaneous adsorption conditions were investigated by varying their mixing method. Polystyrene particles prepared by emulsion polymerization were modified to have positive surface charge by adsorption of polyethylene imine (PEI) on the surface of PS particles. GO prepared by the chemical exfoliation method had negative surface charge from the oxygenated groups. The adsorption of the negatively charged GOs onto the positively charged PS particles was successfully completed, and it was found that a longer adsorption time and a greater difference in the instantaneous relative concentration led PS-GO particles to have more homogeneously coated surfaces without aggregation.

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Nanoengineering of optical resonances

Cited by 2,156 publications

References 23 publications

Nanoparticles Heat through Light Localization

Nanoparticles Heat through Light Localization

Engineering the synthesis of silica–gold nano-urchin particles using continuous synthesis

Adhesion Behavior of Graphene Oxide on Spherical Polymer Particles

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