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Multiple Scattering from Electrospun Nanofibers with Embedded Silver Nanoparticles of Tunable Shape for Random Lasers and White-Light-Emitting Diodes
摘要： Random lasers (RLs) are convenient, tunable, and widely applicable. However, the influence of fluorescence lifetime on the scattering and nanofiber distribution of nanofibers with various shapes of silver nanoparticles (Ag NPs) embedded within is unclear. We prepared polyvinyl alcohol (PVA) nanofibers with Ag NPs through electrospinning (ES) and pyrromethene 597 dye doping. We determined the influences of the particles on scattering enhancement and localized surface plasmon resonance (LSPR) in RLs. The distinct scattering rates and LSPR can be used to control optical properties for sensing devices and other applications. Compared with traditional films, the threshold of the nanofibers with Ag NPs is 35% lower. In addition to improved matching between the LSPR and emission spectra, enhanced coupling of the electric field with nonradiative energy amplifies the radiative emission. Furthermore, the luminescence lifetime shortened by increasing the scattering rate. An excessive scattering rate may accelerate radiative recombination and convert some recombination into nonradiative recombination to produce a more sensitive device. Finally, we applied the prepared nanofibers to a backlight display and fabricated a white-light-emitting diode (LED) with a distinct thickness of nanofibers. The fabricated device is suitable for application in other LEDs and RL devices.
关键词： light scattering,silver nanoparticles,plasmonic,electrospun fibers,random lasers
更新于2025-09-12 10:27:22
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Metal-organic Frameworks Derived Porous Cake-like TiO2 as an Efficient Scattering Layer for Dye-Sensitized Solar Cells
摘要： Porous anatase cake-like TiO2 was prepared by annealing Ti-based metal-organic frameworks (MOFs) MIL-125, which was then used as an efficient scattering layer in dye-sensitized solar cells (DSSCs). The morphology and structure of the prepared porous cake-like TiO2 were characterized by SEM, TEM, and XRD. DSSCs with porous cake-like TiO2 as an efficient scattering layer exhibited a photoelectric conversion efficiency (PCE) of 6.91%, which was greater than that of single P25 TiO2 based DSSCs (3.89%). The improved photoelectric conversion efficiency was attributed to the crucial role of porous cake-like TiO2 in promoting surface area and incident light scattering performance, as demonstrated by N2 adsorption/desorption isotherm analysis, diffuse reflectance spectroscopy, incident photon-to-current efficiency (IPCE) analysis, and electrochemical impedance spectroscopy (EIS).
关键词： MOFs,DSSCs,Porous cake-like TiO2,Light scattering layer
更新于2025-09-11 14:15:04
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3D Multi-Branched SnO2 Semiconductor Nanostructures as Optical Waveguides
摘要： Nanostructures with complex geometry have gathered interest recently due to some unusual and exotic properties associated with both their shape and material. 3D multi-branched SnO2 one-dimensional nanostructrures, characterized by a “node”—i.e., the location where two or more branches originate, are the ideal platform to distribute signals of di?erent natures. In this work, we study how this particular geometrical con?guration a?ects light propagation when a light source (i.e., laser) is focused onto it. Combining scanning electron microscopy (SEM) and optical analysis along with Raman and Rayleigh scattering upon illumination, we were able to understand, in more detail, the mechanism behind the light-coupling occurring at the node. Our experimental ?ndings show that multi-branched semiconductor 1D structures have great potential as optically active nanostructures with waveguiding properties, thus paving the way for their application as novel building blocks for optical communication networks.
关键词： SnO2,waveguiding e?ect in nanostructures,3D multi-branched nanostructures,nanowires,light scattering,tin oxide nanostructure,nano-optics
更新于2025-09-11 14:15:04
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Selected Scattering on Quasi-Ordered Hexagonal Close-Packed Al Nanodents for Tunable Output of White LEDs
摘要： Quasi-ordered hexagonal close-packed Al nanodents, with depths of 30 nm and top-diameters of 300 nm prepared by electrochemical anodizing, are used to manage the output spectrum of white Light Emitting Diodes (LEDs). Signi?cant short wavelength light, with a peak of 450 nm, displays signi?cant scattering enhancements on these Al nanodents with the increment of the angle of the incidence, while long wavelength light, with a peak of 550 nm, shows weaker scattering on Al nanodents with the increment of theincidence angle. Near-?eld and far-?eld simulations reveal the e?ect of light coupling in the holes of Al nanodents on the selected scattering. This work could provide a striking new way to make use of cheap white LEDs.
关键词： Al nanodents,nanomaterials,selected light scattering,white LED
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Kerala, India (12–14 June 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Insulator to semiconductor transition in graphene quantum dots
摘要： Zero dimensional graphene quantum dots (GQDs) exhibit interesting physical and chemical properties due to the edge effect and quantum confinement. As the number of carbon atoms in edge is more than on basal plane, GQDs are more reactive. Room temperature XRD pattern confirms the formation of the GQDs. UV-Visible spectra confirm that GQDs show optical absorption in the visible region. The emission peaks in the photoluminescence spectra are red shifted with the increase of excitation wavelength. Dynamic light scattering (DLS) analysis shows that the average size of the particles is found to be ~65 nm. The frequency dependent electrical transport properties of the GQDs are investigated in a temperature range from 300 to 500 K. Most interestingly, for the first time, the insulator to semiconductor transition of GQD is observed near 400K. The transition mechanism of GQD is discussed with detailed dielectric analysis. The effects of intercalated water on temperature dependent conductivity are clearly discussed. The dielectric relaxation mechanism is explained in the framework of permittivity, conductivity and impedance formalisms. The frequency dependent ac conductivity spectra follows the Jonscher's universal power law. Cole-Cole model is used to investigate the dielectric relaxation mechanism in the sample.
关键词： Graphene Quantum Dots,Insulator to Semiconductor Transition,Dynamic Light Scattering,Dielectric Relaxation,Photoluminescence
更新于2025-09-11 14:15:04
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Optical Microrheology of Protein Solutions Using Tailored Nanoparticles
摘要： This work represents a critical re-examination of the application of dynamic light scattering (DLS)–based tracer particle microrheology to measure the zero shear viscosity of aqueous solutions of different proteins up to very high concentrations. It is demonstrated that a combination of surface-functionalized tracer particles, the use of the so-called 3D-DLS technique, and carefully chosen parameters for the scattering experiments is essential for a reliable and artifact-free determination of the viscosity of highly diverse protein solutions, while keeping the amount of protein to a minimum. The major challenges that arise in such microrheology experiments with protein solutions are discussed and used as guiding principles for the synthesis of all-purpose tracer particles with optimal size and an efficient surface functionalization, and the choice of the appropriate amount of tracers in the sample. Potential problems arising from depletion attractions between the tracer particles induced by the proteins are addressed, and compelling evidences for the absence of such effects are presented. The validity of the approach is corroborated by the perfect agreement between the zero shear viscosity obtained from 3D-DLS-based microrheology and literature data from classical rheological measurements for two vastly different protein–solvent systems up to concentrations close to the arrest transition.
关键词： microrheology,tracer particles,protein viscosity,multiple scattering,3D-dynamic light scattering
更新于2025-09-10 09:29:36
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A polarization sensitive light scattering unit for high throughput screening
摘要： A simple, effective light scattering prototype sensitive to both polarized and depolarized scattering was constructed, and its performance was tested on a variety of pure liquids and optically isotropic and anisotropic polymer solutions and colloidal suspensions. The results, performance, and means to further improvement are reported here. Because of its simplicity and low cost, many identical units can be produced to construct a simultaneous multiple sample light scattering platform that can be used to monitor polymer and colloid solution stability, phase changes, aggregation, degradation, etc. Measurable depolarization was found for a variety of organic liquids and suspensions of both poly?uoroethylene and latex spheres. No detectable depolarization was found for various polymers.
关键词： light scattering,depolarized scattering,colloidal suspensions,polymer solutions,high throughput screening,polarization sensitive
更新于2025-09-10 09:29:36
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Form-stable benzoxazine-urethane alloys for thermally reversible light scattering materials
摘要： Thermally reversible light scattering (TRLS) materials based solely on benzoxazine-urethane (BA-a/PU) alloys were successfully fabricated and demonstrated in this work. The alloys displayed the opaque state below 40 °C. The alloys were transformed to the transparent state upon exposing to the transition temperature of 60–130?°C, depending on the molecular weights and mass concentrations of urethane prepolymers in the BA-a/PU alloys. The optical state transitions were reversible with small hystereses. BA-a/PU alloys exhibited a good optical contrast with 0%T at the light scattering state and almost 100%T at the transparent state. The alloys were glassy and form-stable up to 250?°C, due to the synergistic behavior in the glass transition temperatures. The reaction-induced phase separation effectuated by the incorporation of urethane prepolymer into thermosetting polybenzoxazine, the sizes and local concentrations of the phase-separated urethane microdomains in the supporting polybenzoxazine matrix, and the reversible dissolution and demixing of urethane microdomains and polybenzoxazine phase played crucial roles on TRLS properties of the developed benzoxazine-urethane alloys.
关键词： smart polymers,urethane,polymer blends and alloys,polybenzoxazine,thermally reversible light scattering
更新于2025-09-10 09:29:36
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Automatic classification of label-free cells from small cell lung cancer and poorly differentiated lung adenocarcinoma with 2D light scattering static cytometry and machine learning
摘要： Small cell lung cancer (SCLC) needs to be classified from poorly differentiated lung adenocarcinoma (PDLAC) for appropriate treatment of lung cancer patients. Currently, the classification is achieved by experienced clinicians, radiologists and pathologists based on subjective and qualitative analysis of imaging, cytological and immunohistochemical (IHC) features. Label-free classification of lung cancer cell lines is developed here by using two-dimensional (2D) light scattering static cytometric technique. Measurements of scattered light at forward scattering (FSC) and side scattering (SSC) by using conventional cytometry show that SCLC cells are overlapped with PDLAC cells. However, our 2D light scattering static cytometer reveals remarkable differences between the 2D light scattering patterns of SCLC cell lines (H209 and H69) and PDLAC cell line (SK-LU-1). By adopting support vector machine (SVM) classifier with leave-one-out cross-validation (LOO-CV), SCLC and PDLAC cells are automatically classified with an accuracy of 99.87%. Our label-free 2D light scattering static cytometer may serve as a new, accurate, and easy-to-use method for the automatic classification of SCLC and PDLAC cells.
关键词： static cytometry,2D light scattering,label-free,lung cancer,machine learning
更新于2025-09-10 09:29:36
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A Depolarized Dynamic Light Scattering Method to Calculate Translational and Rotational Diffusion Coefficients of Nanorods
摘要： A new analysis of depolarized dynamic light scattering data is presented, which allows the unambiguous determination of rotational and translational diffusions coefficients of nanorods in suspension. By visualizing data scaling, purely translational diffusive motions can be isolated from vertically polarized scattering, allowing the unique determination of rotational diffusion from the depolarized scattering. The method is applied to nanorods with four different aspect ratios, and compared with theoretical predictions. Diffusion coefficients obtained show good agreement with calculations based on the direct measurements of rod length and diameter. Where the theories are shown to be valid, the method allows the measurement of statistically meaningful particle sizes and aspect ratios.
关键词： depolarized dynamic light scattering,gold nanorods,Brownian motion,translational diffusion,rotational diffusion
更新于2025-09-10 09:29:36