ORCID Profile
0000-0002-7871-4068
Current Organisation
RMIT University
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Physical Chemistry of Materials | Structural Chemistry and Spectroscopy | Nanophotonics | Photonics, Optoelectronics and Optical Communications | Optical Properties of Materials | Macromolecular and Materials Chemistry | Physical Chemistry (Incl. Structural) | Physical Chemistry not elsewhere classified | Nanotechnology | Nanofabrication, Growth and Self Assembly | Optical Physics | Theory and Design of Materials | Nanomaterials | Nanotechnology | Signal Transduction | Nanofabrication growth and self assembly | Functional materials | Nanomaterials | Medical Biotechnology Diagnostics (incl. Biosensors) | Classical and Physical Optics | Nanoelectronics
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Biological Sciences | Energy Transformation not elsewhere classified | Human Diagnostics | Manufacturing not elsewhere classified | Expanding Knowledge in Technology | Information and Communication Services not elsewhere classified | Medical Instruments | Scientific Instruments | Integrated Circuits and Devices |
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B604856K
Abstract: The scattering spectra of single gold nanorods with aspect ratios between 2 and 4 have been examined by dark field microscopy. The results show that the longitudinal plasmon resonance (electron oscillation along the long axis of the rod) broadens as the width of the rods decreases from 14 to 8 nm. This is attributed to electron surface scattering. Analysis of the data using gamma = gamma(bulk) + Anu(F)/L(eff), where L(eff) is the effective path length of the electrons and nu(F) is the Fermi velocity, allows us to determine a value for the surface scattering parameter of A = 0.3. Larger rods with widths of 19 and 30 nm were also examined. These s les also show spectral broadening, which is attributed to radiation d ing. The relative strengths of the surface scattering and radiation d ing effects are in excellent agreement with recent work on spherical gold nanoparticles by Sönnichsen et al., Phys. Rev. Lett., 2002, 88, 077402 and by Berciaud et al., Nano Lett., 2005, 5, 515.
Publisher: Cambridge University Press (CUP)
Date: 02-12-2021
DOI: 10.1017/S0016756820001259
Abstract: Studies that reveal detailed information about trilobite growth, particularly early developmental stages, are crucial for improving our understanding of the phylogenetic relationships within this iconic group of fossil arthropods. Here we document an essentially complete ontogeny of the trilobite Redlichia cf. versabunda from the Cambrian Series 2 (late Stage 4) Ramsay Limestone of Yorke Peninsula in South Australia, including some of the best-preserved protaspides (the earliest biomineralized trilobite larval stage) known for any Cambrian trilobite. These protaspid stages exhibit similar morphological characteristics to many other taxa within the Suborder Redlichiina, especially to closely related species such as Metaredlichia cylindrica from the early Cambrian period of China. Morphological patterns observed across early developmental stages of different groups within the Order Redlichiida are discussed. Although redlichiine protaspides exhibit similar overall morphologies, certain ontogenetic characters within this suborder have potential phylogenetic signal, with different superfamilies characterized by unique trait combinations in these early growth stages.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NR06679A
Abstract: Fabricate nanoparticle dimers with a spherical particle either at the tip, the side or on top of a nanorod.
Publisher: American Chemical Society (ACS)
Date: 16-09-2020
Publisher: American Chemical Society (ACS)
Date: 30-05-2023
Publisher: American Physical Society (APS)
Date: 29-01-2010
Publisher: American Physical Society (APS)
Date: 15-04-2009
Publisher: American Chemical Society (ACS)
Date: 15-12-2017
Publisher: Elsevier BV
Date: 09-2005
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/CH07046
Abstract: Passivation of CdSe semiconductor nanocrystals can be achieved by overcoating the particles with a homogeneous shell of a second semiconductor. Shell layers are grown in monolayer steps to ensure homogeneous growth of the shell. The relative band edges of the two materials determine the photoreactiveity of the resultant core-shell nanocrystals. The critical role of ligands in minimizing nucleation of the shell material during the growth of the passivating layer is emphasized. The delocalization of charge carriers into the shell layers can be followed spectroscopically during the growth processes. The relative spectral shifts are directly correlated to the relative energies of the band edges.
Publisher: American Chemical Society (ACS)
Date: 15-12-2010
DOI: 10.1021/NL903455Z
Abstract: We present an experimental demonstration of strong coupling between a surface plasmon propagating on a planar silver thin film and the lowest excited state of CdSe nanocrystals. Attenuated total reflection measurements demonstrate the formation of plasmon-exciton mixed states, characterized by a Rabi splitting of approximately 112 meV at room temperature. Such a coherent interaction has the potential for the development of nonlinear plasmonic devices, and furthermore, this system is akin to those studied in cavity quantum electrodynamics, thus offering the possibility to study the regime of strong light-matter coupling in semiconductor nanocrystals under easily accessible experimental conditions.
Publisher: American Chemical Society (ACS)
Date: 11-10-2013
DOI: 10.1021/JP306830S
Abstract: Coupling between excitons of CdSe nanocrystal quantum dots (NQDs) and surface plasmon polaritons (SPPs) of an Ag film attached to a prism have been studied by steady-state and transient reflectivity measurements in the Kretschmann geometry. In these experiments, the angle of incidence of the probe beam selects hybrid exciton/SPP states with different wavevectors and exciton/SPP compositions. The dynamics measured in the transient reflectivity experiments are sensitive to the composition of the hybrid states. Specifically, fast dynamics are observed at probe wavevectors where the lower hybrid state has predominant SPP character. In contrast, at probe wavevectors where the lower hybrid state is predominantly excitonic, the dynamics are similar to that measured for CdSe NQDs on glass.
Publisher: American Chemical Society (ACS)
Date: 25-02-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SC05722F
Abstract: Visible light irradiation of 8-aminoquinoline Pd( ii ) complexes initiates photoinduced electron transfer with alkyl halides, affording C–H halogenation over C–C bond adducts. A method for inert C(sp 3 )–H bond halogenation (Br, Cl and I) is reported.
Publisher: American Chemical Society (ACS)
Date: 03-06-2013
DOI: 10.1021/JZ400716J
Abstract: Fabrication of one-dimensional arrays of crystalline nanoparticles with tunable particle size and spacing (down to 20 nm) is demonstrated. The in idual nanocrystals are pentagonal prisms, and the arrays are up to 11 μm in length, with some arrays containing >50 nanocrystals. Precise particle morphology and interparticle spacing can be maintained down the array. The far-field scattering spectra of the arrays show the near-fields of the nanocrystals are coupled. The method is fast and produces precise, well-defined, coupled plasmonic arrays with optical properties that match well to theory.
Publisher: American Physical Society (APS)
Date: 23-11-2010
Publisher: Wiley
Date: 15-07-2015
Publisher: Wiley
Date: 08-05-2023
Abstract: We report a new composite material consisting of silver nanoparticles decorated with three‐dimensional molecular organic cages based on light‐absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano‐resonant interaction between the porphyrin Soret band and the nanoparticle‐localised surface‐plasmon resonance. Time‐resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited‐state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2‐fold current increase in photoelectrochemical water‐splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications.
Publisher: AIP Publishing
Date: 15-08-2009
DOI: 10.1063/1.3195071
Abstract: In this paper, a plasmonic “ac Wheatstone bridge” circuit is proposed and theoretically modeled for the first time. The bridge circuit consists of three metallic nanoparticles, shaped as rectangular prisms, with two nanoparticles acting as parallel arms of a resonant circuit and the third bridging nanoparticle acting as an optical antenna providing an output signal. Polarized light excites localized surface plasmon resonances in the two arms of the circuit, which generate an optical signal dependent on the phase-sensitive excitations of surface plasmons in the antenna. The circuit is analyzed using a plasmonic coupling theory and numerical simulations. The analyses show that the plasmonic circuit is sensitive to phase shifts between the arms of the bridge and has the potential to detect the presence of single molecules.
Publisher: American Physical Society (APS)
Date: 15-12-2014
Publisher: American Chemical Society (ACS)
Date: 18-12-2021
Publisher: Informa UK Limited
Date: 23-04-2020
Publisher: Wiley
Date: 24-11-2017
Publisher: American Chemical Society (ACS)
Date: 12-08-2022
Publisher: Wiley
Date: 22-06-2017
Abstract: Modification of the local density of optical states using metallic nanostructures leads to enhancement in the number of emitted quanta and photocatalytic turnover of luminescent materials. In this work, the fabrication of a metamaterial is presented that consists of a nanowire separated from a metallic mirror by a polymer thin film doped with a luminescent organometallic iridium(III) complex. The large spin-orbit coupling of the heavy metal atom results in an excited state with significant magnetic-dipole character. The nanostructured architecture supports two distinct optical modes and their assignment achieved with the assistance of numerical simulations. The simulations show that one mode is characterized by strong confinement of the electric field and the other by strong confinement of the magnetic field. These modes elicit drastic changes in the emitter's photophysical properties, including dominant nanocavity-derived modes observable in the emission spectra along with significant increases in emission intensity and the total decay rate. A combination of simulations and momentum-resolved spectroscopy helps explain the mechanism of the different interactions of each optical mode supported by the metamaterial with the excited state of the emitter.
Publisher: American Physical Society (APS)
Date: 16-02-2010
Publisher: Wiley
Date: 13-01-2010
DOI: 10.1002/JRS.2557
Publisher: Elsevier BV
Date: 12-2022
Publisher: Wiley
Date: 15-04-2019
Abstract: Simultaneous broadband and high efficiency merits of designer metasurfaces are currently attracting widespread attention in the field of nanophotonics. However, contemporary metasurfaces rarely achieve both advantages simultaneously. For the category of transmissive metadevices, plasmonic or conventional dielectric metasurfaces are viable for either broadband operation with relatively low efficiency or high efficiency at only a selection of wavelengths. To overcome this limitation, dielectric nanoarcs are proposed as a means to accomplish two advantages. Continuous nanoarcs support different electromagnetic resonant modes at localized areas for generating phase retardation. Meanwhile, the geometric nature of nanoarc curvature endows the nanoarcs with full phase coverage of 0-2π due to the Pancharatnam-Berry phase principle. Experimentally incorporated with the chiral-detour phase principle, a few compelling functionalities are demonstrated, such as chiral beamsplitting, broadband holography, and helicity-selective holography. The continuous nanoarc metasurfaces prevail over plasmonic or dielectric discretized building block strategies and the findings lead to novel designs of spin-controllable metadevices.
Publisher: Wiley
Date: 08-05-2023
Abstract: We report a new composite material consisting of silver nanoparticles decorated with three‐dimensional molecular organic cages based on light‐absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano‐resonant interaction between the porphyrin Soret band and the nanoparticle‐localised surface‐plasmon resonance. Time‐resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited‐state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2‐fold current increase in photoelectrochemical water‐splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications.
Publisher: The Optical Society
Date: 22-08-2018
Publisher: American Chemical Society (ACS)
Date: 14-06-2010
DOI: 10.1021/NL101335Z
Abstract: An "electrostatic" eigenmode method based on the coupling of evanescent electric fields is presented for modeling the hybridization of localized surface plasmon resonances in metallic nanoparticles of arbitrary shape. The method yields simple analytical expressions for the hybridized energies and excitation litudes of nanoparticle ensembles. Because of its ease of applicability and simple conceptual basis, we anticipate that the method will be of value in understanding and predicting the effects of interacting plasmonic nanoparticles.
Publisher: Wiley
Date: 28-12-2004
Abstract: We describe the synthesis of quantum-dot (QD) doped silica microspheres and a method by which it is possible to fine-tune the position of the whispering gallery modes (WGMs) produced by the fluorescence emission of CdSe@ZnS doped silica microspheres (5.06 mum in diameter). The method is based on small perturbations to the sphere's refractive index caused by adsorption of thin layers of polyelectrolytes and modification of the radial position of the nanocrystals within the microsphere by means of deposited silica shells.
Publisher: American Chemical Society (ACS)
Date: 11-01-2018
DOI: 10.1021/ACS.NANOLETT.7B04482
Abstract: The photoluminescence of single quantum dots fluctuates between bright (on) and dark (off) states, also termed fluorescence intermittency or blinking. This blinking limits the performance of quantum dot-based devices such as light-emitting diodes and solar cells. However, the origins of the blinking remain unresolved. Here, we use a movable gold micromirror to determine both the quantum yield of the bright state and the orientation of the excited state dipole of single quantum dots. We observe that the quantum yield of the bright state is close to unity for these single QDs. Furthermore, we also study the effect of a micromirror on blinking, and then evaluate excitation efficiency, biexciton quantum yield, and detection efficiency. The mirror does not modify the off-time statistics, but it does change the density of optical states available to the quantum dot and hence the on times. The duration of the on times can be lengthened due to an increase in the radiative recombination rate.
Publisher: American Chemical Society (ACS)
Date: 26-03-2018
Abstract: Many potential applications of quantum dots (QDs) can only be realized once the luminescence from single nanocrystals (NCs) is understood. These applications include the development of quantum logic devices, single-photon sources, long-life LEDs, and single-molecule biolabels. At the single-nanocrystal level, random fluctuations in the QD photoluminescence occur, a phenomenon termed blinking. There are two competing models to explain this blinking: Auger recombination and surface trap induced recombination. Here we use lifetime scaling on core-shell chalcogenide NCs to demonstrate that both types of blinking occur in the same QDs. We prove that Auger-blinking can yield single-exponential on/off times in contrast to earlier work. The surface passivation strategy determines which blinking mechanism dominates. This study summarizes earlier studies on blinking mechanisms and provides some clues that stable single QDs can be engineered for optoelectronic applications.
Publisher: American Chemical Society (ACS)
Date: 17-06-2013
DOI: 10.1021/NN401775E
Abstract: Gold nanoparticles and nearby fluorophores interact via electromagnetic coupling upon light excitation. We determine the distance and wavelength dependence of this coupling theoretically and experimentally via steady-state and time-resolved fluorescence spectroscopy. For the first time, the fluorescence quenching of four different dye molecules, which absorb light at different wavelengths across the visible spectrum and into the near-infrared, is studied using a rigid silica shell as a spacer. A comprehensive experimental determination of the distance dependence from complete quenching to no coupling is carried out by a systematic variation of the silica shell thickness. Electrodynamic theory predicts the observed quenching quantitatively in terms of energy transfer from the molecular emitter to the gold nanoparticle. The plasmonic field enhancement in the vicinity of the 13 nm gold nanoparticles is calculated as a function of distance and excitation wavelength and is included in all calculations. Relative radiative and energy transfer rates are determined experimentally and are in good agreement with calculated rates. We demonstrate and quantify the severe effect of dye-dye interactions on the fluorescence properties of dyes attached to the surface of a silica nanoparticle in control experiments. This allows us to determine the experimental conditions, under which dye-dye interactions do not affect the experimental results.
Publisher: Springer Science and Business Media LLC
Date: 20-09-2017
DOI: 10.1038/S41467-017-00588-3
Abstract: Hybrid organic-inorganic halide perovskites are low-cost solution-processable solar cell materials with photovoltaic properties that rival those of crystalline silicon. The perovskite films are typically sandwiched between thin layers of hole and electron transport materials, which efficiently extract photogenerated charges. This affords high-energy conversion efficiencies but results in significant performance and fabrication challenges. Herein we present a simple charge transport layer-free perovskite solar cell, comprising only a perovskite layer with two interdigitated gold back-contacts. Charge extraction is achieved via self-assembled monolayers and their associated dipole fields at the metal-perovskite interface. Photovoltages of ~600 mV generated by self-assembled molecular monolayer modified perovskite solar cells are equivalent to the built-in potential generated by in idual dipole layers. Efficient charge extraction results in photocurrents of up to 12.1 mA cm −2 under simulated sunlight, despite a large electrode spacing.
Publisher: American Chemical Society (ACS)
Date: 15-06-2022
DOI: 10.1021/JACS.2C02011
Abstract: Photoredox catalysts are primarily selected based on ground and excited state properties, but their activity is also intrinsically tied to the nature of their reduced (or oxidized) intermediates. Catalyst reactivity often necessitates an inherent instability, thus these intermediates represent a mechanistic turning point that affords either product formation or side-reactions. In this work, we explore the scope of a previously demonstrated side-reaction that partially saturates one pyridine ring of the ancillary ligand in heteroleptic iridium(III) complexes. Using high-throughput synthesis and screening under photochemical conditions, we identified different chemical pathways, ultimately governed by ligand composition. The ancillary ligand was the key factor that determined photochemical stability. Following photoinitiated electron transfer from a sacrificial tertiary amine, the reduced intermediate of complexes containing 1,10-phenanthroline derivatives exhibited long-term stability. In contrast, complexes containing 2,2'-bipyridines were highly susceptible to hydrogen atom transfer and ancillary ligand modification. Detailed characterization of selected complexes before and after transformation showed differing effects on the ground and excited state reduction potentials dependent on the nature of the cyclometalating ligands and excited states. The implications of catalyst stability and reactivity in chemical synthesis was demonstrated in a model photoredox reaction.
Publisher: American Chemical Society (ACS)
Date: 05-08-2009
DOI: 10.1021/NN900296Q
Abstract: We report on the observation of an intermediate state in the blinking of single CdSe/CdS core-shell nanocrystals. This state has a low quantum yield and connects the "on" and "off" states commonly observed in the photoluminescence blinking of in idual nanocrystals. We find that the transitions between these two emitting states follow nearly single-exponential statistics. The transitions from the "on" state to this intermediate state result from changes in the surface passivation of the nanocrystal. The data are consistent with photoinduced, adsorption/desorption events that take place at the surface of the nanocrystals. The trion state leads to a reduction in photoluminescence in nanocrystals.
Publisher: Wiley
Date: 24-09-2023
Publisher: American Chemical Society (ACS)
Date: 17-03-2009
DOI: 10.1021/JP900887R
Publisher: American Chemical Society (ACS)
Date: 10-03-2016
DOI: 10.1021/ACS.NANOLETT.6B00310
Abstract: Reversible exchange of photons between a material and an optical cavity can lead to the formation of hybrid light-matter states where material properties such as the work function [ Hutchison et al. Adv. Mater. 2013 , 25 , 2481 - 2485 ], chemical reactivity [ Hutchison et al. Angew. Chem., Int. Ed. 2012 , 51 , 1592 - 1596 ], ultrafast energy relaxation [ Salomon et al. Angew. Chem., Int. Ed. 2009 , 48 , 8748 - 8751 Gomez et al. J. Phys. Chem. B 2013 , 117 , 4340 - 4346 ], and electrical conductivity [ Orgiu et al. Nat. Mater. 2015 , 14 , 1123 - 1129 ] of matter differ significantly to those of the same material in the absence of strong interactions with the electromagnetic fields. Here we show that strong light-matter coupling between confined photons on a semiconductor waveguide and localized plasmon resonances on metal nanowires modifies the efficiency of the photoinduced charge-transfer rate of plasmonic derived (hot) electrons into accepting states in the semiconductor material. Ultrafast spectroscopy measurements reveal a strong correlation between the litude of the transient signals, attributed to electrons residing in the semiconductor and the hybridization of waveguide and plasmon excitations.
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B405157B
Publisher: Informa UK Limited
Date: 11-12-2018
Publisher: American Chemical Society (ACS)
Date: 10-2014
DOI: 10.1021/JP506402M
Publisher: AIP Publishing
Date: 15-02-2010
DOI: 10.1063/1.3313935
Publisher: AIP Publishing
Date: 21-01-2013
DOI: 10.1063/1.4775382
Abstract: The plasmonic J-pole antenna is the nanoscale version of a radio frequency design, consisting of a half wavelength arm connected to a quarter wavelength feed pair. Here, we report on an optical J-pole antenna that displays both a dipole (1015 nm) and quadrupole resonance (653 nm). The excitation of the quadrupole resonance is optimum at an angle of incidence directly related to the geometry of the antenna, demonstrating the flexibility of the design. The J-pole antenna shows great promise for enhancing and shaping the angular emission pattern of quantum emitters.
Publisher: IOP Publishing
Date: 12-05-2023
Abstract: Post transition metal chalcohalides are an emerging class of semiconductor materials for optoelectronic applications. Within this class, bismuth oxyiodide (BiOI) is of particular interest due to its high environmental stability, low toxicity, and defect tolerance considered typical of ‘ns 2 ’ materials. Here we fabricate BiOI thin films using a solution-processed method that affords pin-hole free highly pure films without any residual carbon or other contaminant species. Based on these films, solution processed all-inorganic solar cells with an architecture ITO/NiO x /BiOI/ZnO/Al are fabricated for the first time. Additional device improvements are realised by templating BiOI thin film growth to attain efficiencies that rival some of the best vacuum deposited devices. The BiOI thin films and devices outlined here are an excellent platform for the further development of solution processed bismuth chalcohalide optoelectronic devices.
Publisher: American Chemical Society (ACS)
Date: 13-02-2017
Abstract: Asymmetric nanoparticle trimers composed of particles with increasing diameter act as "plasmonic lenses" and have been predicted to exhibit ultrahigh confinement of electromagnetic energy in the space between the two smallest particles. Here we present an electrostatic self-assembly approach for creating gold nanoparticle trimers with an assembly yield of over 60%. We demonstrate that the trimer assembly leads to characteristic red-shifts and show the localization of the relevant plasmon modes by means of cathodoluminescence and electron energy loss spectroscopy. The results are analyzed in terms of surface plasmon hybridization.
Publisher: American Chemical Society (ACS)
Date: 12-03-2008
DOI: 10.1021/NN7003469
Abstract: The photoluminescence (PL) of 2D monolayers of CdSe/CdS/ZnS semiconductor nanocrystals (NCs) deposited on gold substrates and incorporated into electrochemical cells has been studied. By combining simultaneous cyclic voltammetry and confocal microscopy it is demonstrated that when a positive potential is applied to the film in an acetonitrile electrolyte, the PL is irreversibly quenched. This is irrespective of whether the s les are under an inert atmosphere or exposed to air or water vapor. When a negative potential is applied under nitrogen, quenching is also observed however, it is reversible. Conversely when a negative potential is applied to the NC films in aerated acetonitrile, the PL intensity increases. The enhancement of the PL is stable for at least 180 s while the potential is held at -1.0 V (vs Ag quasi-reference electrode). When the potential is removed the PL intensity returns to the starting value. These results clearly indicate that photobrightening and charge carrier injection are coupled processes. On the basis of these data, we propose a simple kinetic model that explains the origins of photobrightening.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4NR06650B
Abstract: Aluminum V-antennas on silicon display significant alterations to their plasmon resonances due to the presence of the optically-dense silicon substrate and adjacent antennas, as well as a high sensitivity to the substrate's native oxide layer. The effect of the aluminium band-gap is also shown to affect the V-antennas’ resonances.
Publisher: American Physical Society (APS)
Date: 08-04-2010
Publisher: Springer Science and Business Media LLC
Date: 21-02-2006
Publisher: American Chemical Society (ACS)
Date: 23-09-2019
DOI: 10.1021/JACS.9B07370
Abstract: We report the discovery of a tandem catalytic process to reduce energy demanding substrates, using the [Ir(ppy)
Publisher: The Optical Society
Date: 14-05-2014
DOI: 10.1364/OL.39.002994
Publisher: American Chemical Society (ACS)
Date: 21-03-2016
Abstract: Hot charge carrier extraction from metallic nanostructures is a very promising approach for applications in photocatalysis, photovoltaics, and photodetection. One limitation is that many metallic nanostructures support a single plasmon resonance thus restricting the light-to-charge-carrier activity to a spectral band. Here we demonstrate that a monolayer of plasmonic nanoparticles can be assembled on a multistack layered configuration to achieve broadband, near-unit light absorption, which is spatially localized on the nanoparticle layer. We show that this enhanced light absorbance leads to ∼40-fold increases in the photon-to-electron conversion efficiency by the plasmonic nanostructures. We developed a model that successfully captures the essential physics of the plasmonic hot electron charge generation and separation in these structures. This model also allowed us to establish that efficient hot carrier extraction is limited to spectral regions where (i) the photons have energies higher than the Schottky junctions and (ii) the absorption of light is localized on the metal nanoparticles.
Publisher: Wiley
Date: 09-05-2019
Abstract: 2D freestanding nanocrystal superlattices represent a new class of advanced metamaterials in that they can integrate mechanical flexibility with novel optical, electrical, plasmonic, and magnetic properties into one multifunctional system. The freestanding 2D superlattices reported to date are typically constructed from symmetrical constituent building blocks, which have identical structural and functional properties on both sides. Here, a general ligand symmetry-breaking strategy is reported to grow 2D Janus gold nanocrystal superlattice sheets with nanocube morphology on one side yet with nanostar on the opposite side. Such asymmetric metallic structures lead to distinct wetting and optical properties as well as surface-enhanced Raman scattering (SERS) effects. In particular, the SERS enhancement of the nanocube side is about 20-fold of that of the nanostar side, likely due to the combined "hot spot + lightening-rod" effects. This is nearly 700-fold of SERS enhancement as compared with the symmetric nanocube superlattices without Janus structures.
Publisher: Elsevier BV
Date: 05-2021
Publisher: The Optical Society
Date: 11-10-2018
Publisher: Wiley
Date: 09-01-2006
Publisher: Wiley
Date: 17-09-2019
Publisher: American Physical Society (APS)
Date: 09-07-2012
Publisher: American Chemical Society (ACS)
Date: 17-05-2010
DOI: 10.1021/NL100423Z
Abstract: We present a theory for determining the localized surface plasmon resonance shifts of arbitrarily shaped metal nanoparticles on a substrate. Using a pseudoparticle concept, an expression for the particle-substrate interaction is derived, providing both physical insight and formulas to estimate the shifted plasmon resonance. The theory is verified against measured scattering spectra of nanorods on substrates. Simple formulas are provided to calculate the resonance of nanorods, spheres, and ellipsoids on dielectric substrate.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3TC32041C
Publisher: AIP Publishing
Date: 10-2011
DOI: 10.1063/1.3650900
Abstract: Quantum dot–plasmon waveguide systems are of interest for the active control of plasmon propagation, and consequently, the development of active nanophotonic devices such as nano-sized optical transistors. This paper is concerned with how varying aspect ratio of the waveguide cross-section affects the quantum dot–plasmon coupling. We compare a stripe waveguide with an equivalent nanowire, illustrating that both waveguides have a similar coupling strength to a nearby quantum dot for small waveguide cross-section, thereby indicating that stripe lithographic waveguides have strong potential use in quantum dot–plasmon waveguide systems. We also demonstrate that changing the aspect ratio of both stripe and wire waveguides can increase the spontaneous emission rate of the quantum dot into the plasmon mode, by up to a factor of five. The results of this paper will contribute to the optimisation of quantum dot–plasmon waveguide systems and help pave the way for the development of active nanophotonics devices.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA05307A
Abstract: A simple, versatile, high-throughput nanofabrication method based on electrostatic self-assembly is developed for the large-scale generation of well-defined asymmetric plasmonic dimers, enabling the study of interparticle plasmon coupling and the "hot-spot" phenomenon in SERS.
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B607661K
Publisher: AIP Publishing
Date: 15-11-2009
DOI: 10.1063/1.3262625
Abstract: The use of metal stripes for the guiding of plasmons is a well established technique for the infrared regime and has resulted in the development of a myriad of passive optical components and sensing devices. However, the plasmons suffer from large losses around sharp bends, making the compact design of nanoscale sensors and circuits problematic. A compact alternative would be to use evanescent coupling between two sufficiently close stripes, and thus we propose a compact interferometer design using evanescent coupling. The sensitivity of the design is compared with that achieved using a hand-held sensor based on the Kretschmann style surface plasmon resonance technique. Modeling of the new interferometric sensor is performed for various structural parameters using finite-difference time-domain and COMSOL Multiphysics. The physical mechanisms behind the coupling and propagation of plasmons in this structure are explained in terms of the allowed modes in each section of the device.
Publisher: American Chemical Society (ACS)
Date: 07-09-2011
DOI: 10.1021/NL202080A
Abstract: We present experimental data on the light scattering properties of linear chains of gold nanoparticles with up to six nanoparticles and an interparticle spacing of 1 nm. A red shift of the surface plasmon resonance with increasing chain length is observed. An exponential model applied to the experimental data allows determination of an asymptotic maximum resonance at a chain length of 10-12 particles. The optical data are compared with analytical and numerical calculation methods (EEM and BEM).
Publisher: American Physical Society (APS)
Date: 07-2019
Publisher: American Chemical Society (ACS)
Date: 28-03-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR01592H
Abstract: We show how a combination of near- and far-field coupling of the localised surface plasmon resonances in aluminium nanoparticles deposited on TiO2 films greatly enhances the visible light photocatalytic activity of the semiconductor material. We demonstrate two orders of magnitude enhancement in the rate of decomposition of methylene blue under visible light illumination when the surface of TiO2 films is decorated with gratings of Al nanoparticle dimers.
Publisher: AIP Publishing
Date: 10-2019
DOI: 10.1063/1.5113650
Abstract: Spatial frequency filtering is a fundamental enabler of information processing methods in biological and technical imaging. Most filtering methods, however, require either bulky and expensive optical equipment or some degree of computational processing. Here, we experimentally demonstrate real-time, on-chip, all-optical spatial frequency filtering using a thin-film perfect absorber structure. We experimentally demonstrate edge enhancement of an litude image and conversion of phase gradients to intensity modulation in an image. The device is used to demonstrate enhancement of an image of pond algae.
Publisher: Oxford University Press (OUP)
Date: 05-05-2020
DOI: 10.1017/S1431927620000094
Abstract: The excitability of local surface plasmon modes in radial trimers composed of gold nanorods was mapped using hyperspectral cathodoluminescence (CL) in the scanning electron microscope. In symmetric trimers, the local plasmon resonances could be excited most effectively at the ends of in idual rods. Introducing asymmetry into the structure breaks the degeneracy of the dipole modes and changes the excitability of transverse dipole modes in different directions. CL in the scanning electron microscope has great potential to interrogate in idual nanophotonic structures and is a complement to electron energy loss spectroscopy and optical microscopy.
Publisher: American Chemical Society (ACS)
Date: 21-02-2023
Publisher: The Optical Society
Date: 15-08-2014
DOI: 10.1364/OL.39.004938
Publisher: American Chemical Society (ACS)
Date: 22-01-2019
Publisher: Wiley
Date: 02-05-2019
Publisher: Optica Publishing Group
Date: 10-12-2009
DOI: 10.1364/OE.17.023655
Publisher: Wiley
Date: 29-11-2020
Abstract: Anti-reflective surfaces are of great interest for optical devices, sensing, photovoltaics, and photocatalysis. However, most of the anti-reflective surfaces lack in situ tunability of the extinction with respect to wavelength. This communication demonstrates a tunable anti-reflective surface based on colloidal particles comprising a metal core with an electrochromic polymer shell. Random deposition of these particles on a reflective surface results in a decrease in the reflectance of up to 99.8% at the localized surface plasmon resonance frequency. This narrow band feature can be tuned by varying the pH or by application of an electric potential, resulting in wavelength shifts of up to 30 nm. Electrophoretic particle deposition is shown to be an efficient method for controlling the interparticle distance and thereby further optimizing the overall efficiency of the anti-reflective metasurface.
Publisher: AIP Publishing
Date: 29-11-2016
DOI: 10.1063/1.4968840
Abstract: A metasurface comprising an array of silver nanorods supported by a thin film of the phase change material vanadium dioxide is used to rotate the primary polarization axis of visible light at a pre-determined wavelength. The dimensions of the rods were selected such that, across the two phases of vanadium dioxide, the two lateral localized plasmon resonances (in the plane of the metasurface) occur at the same wavelength. Illumination with linearly polarized light at 45° to the principal axes of the rod metasurface enables excitation of both of these resonances. Modulating the phase of the underlying substrate, we show that it is possible to reversibly switch which axis of the metasurface is resonant at the operating wavelength. Analysis of the resulting Stokes parameters indicates that the orientation of the principal linear polarization axis of the reflected signal is rotated by 90° around these wavelengths. Dynamic metasurfaces such as these have the potential to form the basis of an ultra-compact, low-energy multiplexer or router for an optical signal.
Publisher: AIP Publishing
Date: 10-04-2006
DOI: 10.1063/1.2193967
Abstract: We have explored the influence of different matrices on the emission line shape of in idual homogeneously coated CdSe∕CdS∕ZnS nanocrystals. The results obtained corroborate previous observations of a correlation between blinking events and spectral diffusion, but in addition we have found that the extent of spectral diffusion is almost independent of the dielectric environment of the nanocrystal (NC). Additionally, we report the observation of a correlation between the linewidth and emission energy which is not expected to occur in the spherical-symmetric NCs employed in this work. The implications of these results are discussed.
Publisher: Elsevier BV
Date: 11-2019
Publisher: American Chemical Society (ACS)
Date: 16-06-2017
Publisher: Informa UK Limited
Date: 25-09-2020
Publisher: American Chemical Society (ACS)
Date: 03-05-2021
Publisher: American Chemical Society (ACS)
Date: 07-01-2019
Publisher: American Chemical Society (ACS)
Date: 30-09-2019
Publisher: American Chemical Society (ACS)
Date: 24-02-2021
Publisher: American Chemical Society (ACS)
Date: 26-09-2018
Publisher: Optica Publishing Group
Date: 23-11-2020
Abstract: The optoelectronic properties of asymmetric metal nanostructures are of current interest for applications in photonics, sensing, and catalysis. Here, we break the symmetry of the localized surface plasmon resonance of gold nanorods by selective overgrowth of a single tip via a high-yield ( --> 80 % ) wet-chemical method. While optical spectroscopy exhibits a bathochromic shift of the nanoparticle plasmon resonance, cathodoluminescence and electron energy loss spectroscopy measurements reveal a breaking of the symmetry of the associated localized surface plasmon resonance mode, which results in the subwavelength concentration of electromagnetic energy. The simple, one-step postsynthetic modification allows control of nanoparticle structural parameters, and we demonstrate how the asymmetric energy redistribution leads to increases in the surface-enhanced Raman scattering of a model analyte attached to the surface of the nanostructures. The spatial localization of energy in these nanostructures may find applications in nanofocusing, nanoimaging, and light harvesting.
Start Date: 2023
End Date: 2025
Funder: Australian Research Council
View Funded ActivityStart Date: 2021
End Date: 2022
Funder: Australian Research Council
View Funded ActivityStart Date: 2020
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2020
Funder: Australian Research Council
View Funded ActivityStart Date: 2016
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 2011
End Date: 2011
Funder: Australian Research Council
View Funded ActivityStart Date: 2011
End Date: 2014
Funder: Australian Research Council
View Funded ActivityStart Date: 09-2014
End Date: 01-2020
Amount: $746,214.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2011
End Date: 03-2014
Amount: $418,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 05-2021
End Date: 05-2022
Amount: $302,154.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2016
End Date: 12-2016
Amount: $300,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2023
End Date: 12-2025
Amount: $388,585.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2020
End Date: 05-2022
Amount: $755,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2011
End Date: 12-2011
Amount: $366,384.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2016
End Date: 12-2019
Amount: $381,800.00
Funder: Australian Research Council
View Funded Activity