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Unraveling the origin of chirality from plasmonic nanoparticle-protein complexes
摘要： Plasmon-coupled circular dichroism has emerged as a promising approach for ultrasensitive detection of biomolecular conformations through coupling between molecular chirality and surface plasmons. Chiral nanoparticle assemblies without chiral molecules present also have large optical activities. We apply single-particle circular differential scattering spectroscopy coupled with electron imaging and simulations to identify both structural chirality of plasmonic aggregates and plasmon-coupled circular dichroism induced by chiral proteins. We establish that both chiral aggregates and just a few proteins in interparticle gaps of achiral assemblies are responsible for the ensemble signal, but single nanoparticles do not contribute. We furthermore find that the protein plays two roles: It transfers chirality to both chiral and achiral plasmonic substrates, and it is also responsible for the chiral three-dimensional assembly of nanorods. Understanding these underlying factors paves the way toward sensing the chirality of single biomolecules.
关键词： chiral nanoparticle assemblies,single-particle circular differential scattering spectroscopy,plasmonic aggregates,biomolecular conformations,chiral proteins,Plasmon-coupled circular dichroism
更新于2025-09-12 10:27:22
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Surface resonance properties of pure Cu and Cu80Zr20 metallic glass films with nanoparticles induced by pulsed-laser dewetting process
摘要： Pure Cu and Cu80Zr20 thin films with a thickness of 10 nm were deposited on glass substrates using a high-vacuum sputtering system. A pulsed-laser dewetting process was then performed using a NIR laser system. For the pure Cu film, nanoparticles were produced for the accumulated energy (AE) densities in the range of 0.6~11 J/cm2. The particle size was found to increase with increasing scanning speed and repetition rate, and with decreasing power. For the Cu80Zr20 thin film, nanoparticles were formed under all AE values under consideration. The nanoparticles consisted almost entirely of Cu; with the Zr atoms being repelled to the bottom of the nanoparticle and surroundings. The optical absorption peak wavelengths for the Cu and Cu80Zr20 films produced under different dewetting conditions all lay in the range of 580~700 nm. Hence, it was inferred that the nanoparticles produced in the two films had a similar size, shape and composition.
关键词： surface resonance properties,Pulsed-laser dewetting,metallic glass,nanoparticle
更新于2025-09-12 10:27:22
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The processes underlying the laser photochromic effect in colloidal plasmonic nanoparticle aggregates
摘要： We have studied the dynamic and static processes occurring in disordered multiparticle colloidal Ag aggregates with natural structure and affecting their plasmonic absorption spectra under pico- and nanosecond pulsed laser radiation, as well as the physical origin responsible for these processes. We have shown that depending on the duration of the laser pulse, the mechanisms of laser modification of such aggregates can be associated both with changes in the resonant properties of particles due to their heating and melting (picosecond irradiation mode) and with the particle shifts in resonant domains of aggregates (nanosecond pulses) which depend on the wavelength, intensity and polarization of the radiation. These mechanisms results in formation of a narrow dip in the plasmonic absorption spectrum of aggregates near the laser radiation wavelength and affect the shape and position of the dip. The effect of polydispersity of nanoparticle aggregates on laser photochromic reaction has been studied.
关键词： Nanoparticle,surface plasmon resonance,photochromic process,pulsed laser radiation
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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Design and Analysis of a Ag Rhombus Nanoparticle Film-Coupled Plasmonic Nanostructure
摘要： We design a coupled plasmonic nanostructure, which consists of a Ag rhombus nanoparticle positioned over a silver ?lm, separated by a dielectric spacer layer, and perform numerical analysis by calculating the radiation loss resistance of this nanostructure as the perfect electric conductor metal based on the theory of transmission line modes. Compared with the nanocube or triangular nanodisk ?lm-coupled plasmonic nanostructures introduced in the previous works, a stronger electric ?eld enhancement was achieved in the Ag rhombus nanoparticle ?lm-coupled nanostructure because of the fact that the sharp tip of the rhombus nanoparticle can generate ?eld enhancement at a hot spot. In order to demonstrate that the sharp tip can con?ne the electromagnetic energies strongly, we also have calculated the Purcell factor and the far-?eld directivity of the quantum emitter in the vicinity of this nanostructure.
关键词： Purcell factor,electric ?eld enhancement,plasmonic nanostructure,Ag rhombus nanoparticle,far-?eld directivity
更新于2025-09-11 14:15:04
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Functional Macromolecule‐Enabled Colloidal Synthesis: From Nanoparticle Engineering to Multifunctionality
摘要： The synthesis of well-defined inorganic colloidal nanostructures using functional macromolecules is an enabling technology that offers the possibility of fine-tuning the physicochemical properties of nanomaterials and has contributed to a broad range of practical applications. The utilization of functional reactive polymers and their colloidal assemblies leads to a high level of control over structural parameters of inorganic nanoparticles that are not easily accessible by conventional methods based on small-molecule ligands. Recent advances in polymerization techniques for synthetic polymers and newly exploited functions of natural biomacromolecules have opened up new avenues to monodisperse and multifunctional nanostructures consisting of integrated components with distinct chemistries but complementary properties. Here, the evolution of colloidal synthesis of inorganic nanoparticles is revisited. Then, the new developments of colloidal synthesis enabled by functional macromolecules and practical applications associated with the resulting optical, catalytic, and structural properties of colloidal nanostructures are summarized. Finally, a perspective on new and promising pathways to novel colloidal nanostructures built upon the continuous development of polymer chemistry, colloidal science, and nanochemistry is provided.
关键词： polymer chemistry,nanochemistry,multifunctionality,colloidal synthesis,functional macromolecules,nanoparticle engineering,colloidal science
更新于2025-09-11 14:15:04
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Unidirectional Light Scattering With High $f/b$ at Optical Frequencies Based on Coupled Nanoantennas
摘要： We propose an optically coupled nanoantenna which contains an asymmetric dimer of core-dual shells nanoparticles, and the individual nanoparticle consisting of two identical metal strips that separated by a dielectric spacer known as the metal-dielectric-metal (MDM) structure. According to the dipole-dipole theory and the Mie theory, we theoretically and numerically demonstrate that this design can provide unidirectional forward scattering along the incident axis of light with high f /b radio (known as the ratio of scattering spectra to forward and backward direction) and narrow beam-width owing to interference between electric dipole and magnetic high-order modes. We also ?nd that all properties of this nanoantenna that the performance of it is related with the gap separation of the asymmetric dimer. Comparing with the asymmetric dimer of pure metal nanoparticles and the symmetric dimer of MDM nanoparticles, the proposed nanoantenna has higher directivity and low loss at the same time, due to effectively coupled electric dipole mode and magnetic multipole modes. The ultra-directional nanoantenna may shed new light to overcome power losses and low directivity of coupled nanoantennas, which can ?nd various applications in bio-sensing and metamaterials.
关键词： dipole-dipole theory,Coupled nanoantenna,Mie theory,core-dual shells nanoparticle
更新于2025-09-11 14:15:04
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Enhanced Light Extraction from Bottom Emission OLEDs by High Refractive Index Nanoparticle Scattering Layer
摘要： High refractive index nanoparticle material was applied as a scattering layer on the inner side of a glass substrate of a bottom emission organic light emitting diode (OLED) device to enhance light extraction and to improve angular color shift. TiO2 and YSZ (Yttria Stabilized Zirconia; Y2O3-ZrO2) were examined as the high refractive index nanoparticles. The nanoparticle material was formed as a scattering layer on a glass substrate by a coating method, which is generally used in the commercial display manufacturing process. Additionally, a planarization layer was coated on the scattering layer with the same method. The implemented nanoparticle material and planarization material endured, without deformation, the subsequent thermal annealing process, which was carried out at temperature ranged to 580 °C. We demonstrated a practical and highly efficient OLED device using the conventional display manufacturing process by implementing the YSZ nanoparticle. We obtained a 38% enhanced luminance of the OLED device and a decreased angular color change compared to a conventional OLED device.
关键词： efficiency,display,light extraction,high refractive index,OLED,outcoupling,scatter,YSZ,nanoparticle
更新于2025-09-11 14:15:04
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Emission behaviors of colloidal quantum dots linked onto synthesized metal nanoparticles
摘要： Emission Behaviors of Colloidal Quantum Dots Linked onto Synthesized Metal Nanoparticles. With two different residual surfactants, four different metal nanoparticles (NPs), including two Au NPs and two Ag NPs are synthesized for linking with red-emitting CdZnSeS/ZnS colloidal quantum dots (QDs) to enhance QD emission efficiency. Those metal NPs are first connected with amino polyethylene glycol thiol of different molecular weights to avoid aggregation and make them positively charged. They can attract negatively charged QDs for inducing surface plasmon (SP) coupling such that either QD absorption or emission and hence overall color conversion efficiency can be enhanced. The enhancement of QD emission efficiency is evaluated through the comparison of time-resolved photoluminescence behaviors under different QD linkage conditions. Such results are confirmed by the measurement of the emission quantum efficiency of QD. It is found that by linking QDs onto Ag NPs, the QD emission efficiency is more enhanced, when compared with Au NPs. Also, depending on the synthesis process, the residual surfactant of citrate leads to a relatively larger increment in QD emission efficiency, when compared to the surfactant of cetrimonium chloride. A more enhanced QD emission efficiency is caused by a higher QD linkage capability and a stronger SP coupling effect.
关键词： colloidal quantum dot,emission efficiency,surface plasmon coupling,synthesized metal nanoparticle
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Controlling the Temporal Trajectory of Solitons in Silver Nanoparticle Doped Fibre
摘要： Silver nanoparticle doped photonic crystal fibres (SNPCF) exhibit negative Kerr nonlinearity over certain wavelength ranges [1]. At some specific wavelength, the nonlinearity vanishes representing a zero-nonlinearity (ZN) point, allowing for new propagation dynamics of solitons due to controllable interaction of dispersion and nonlinearity [2]. Here we show that the presence of a ZN point significantly influences the temporal trajectory of a soliton during the process of supercontinuum (SC) generation. The input pulse launched in the anomalous dispersion domain but with negative nonlinearity, close to zero dispersion wavelength (ZDW), generates bright solitons exhibiting complex acceleration, deceleration, and shaping behaviour, due to Raman effect, nonlinear dispersion and the four-wave mixing interaction processes. We study the variations of dynamics for different ZN points demonstrating the efficient control of soliton trajectories.
关键词： supercontinuum generation,solitons,nonlinear dispersion,zero-nonlinearity point,silver nanoparticle doped fibre
更新于2025-09-11 14:15:04