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Evaluation of Nanoplasmonic Optical Fiber Sensors Based on D-Type and Suspended Core Fibers with Metallic Nanowires
摘要： The introduction of metallic nanostructures in optical fibers has revolutionized the field of plasmonic sensors since they produce sharper and fine-tuned resonances resulting in higher sensitivities and resolutions. This article evaluates the performance of three different plasmonic optical fiber sensors based on D-type and suspended core fibers with metallic nanowires. It addresses how their different materials, geometry of the components, and their relative position can influence the coupling between the localized plasmonic modes and the guided optical mode. It also evaluates how that affects the spatial distributions of optical power of the different modes and consequently their overlap and coupling, which ultimately impacts the sensor performance. In this work, we use numerical simulations based on finite element methods to validate the importance of tailoring the features of the guided optical mode to promote an enhanced coupling with the localized modes. The results in terms of sensitivity and resolution demonstrate the advantages of using suspended core fibers with metallic nanowires.
关键词： suspended core fiber,metallic nanowires,finite-element method,optical fiber sensors,D-type fiber,surface plasmon resonance,plasmonic refractive index sensor
更新于2025-09-16 10:30:52
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Effect of incorporating different polyanilinea??surface modified nanosilica content into polyurethanea??based quasia??solida??state electrolyte for dyea??sensitized solar cells
摘要： Polyaniline-surface modified nanosilica (S-PANi) was incorporated into polyurethane (PU) to form a polymer matrix able to entrap liquid electrolyte and to function as a quasi-solid state electrolyte (QSE) in dye-sensitized solar cells (DSSCs). Nanosilica was first synthesized via sol–gel technique and was post modified with aniline to form S-PANi. The effects of introducing different S-PANi content (5, 10, 15, and 20 wt%) on the nanoparticle distribution, surface morphology, surface porosity, thermal stability, and the structure of the PU matrix were analyzed using transmitted and reflected light microscopes, TGA and X-ray powder diffraction. Additionally, polymer matrix absorptivity, conductivity, and ion diffusion of the formulated QSEs were investigated by using a digital analytical balance, the AC impedance method, and cyclic voltammetry. Lastly, all of the formulated quasi-solid-state electrolytes were applied for use in DSSCs wherein their charge recombination, photovoltaic performance, and lifespan were measured. The quasi-solid-state electrolyte based on 15 wt% S-PANi (PU-15%S-PANi) exhibited the highest light-to-energy conversion efficiency, namely 3.17%, with an open circuit voltage of 708 mV, a short circuit current of 4.13 mA cm?2, and a fill factor of 0.65.
关键词： films,swelling,nanoparticles,nanowires and nanocrystals,optical and photovoltaic applications,polyurethane
更新于2025-09-16 10:30:52
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Transparent multispectral photodetectors mimicking the human visual system
摘要： Compact and lightweight photodetection elements play a critical role in the newly emerging augmented reality, wearable and sensing technologies. In these technologies, devices are preferred to be transparent to form an optical interface between a viewer and the outside world. For this reason, it is of great value to create detection platforms that are imperceptible to the human eye directly onto transparent substrates. Semiconductor nanowires (NWs) make ideal photodetectors as their optical resonances enable parsing of the multi-dimensional information carried by light. Unfortunately, these optical resonances also give rise to strong, undesired light scattering. In this work, we illustrate how a new optical resonance arising from the radiative coupling between arrayed silicon NWs can be harnessed to remove reflections from dielectric interfaces while affording spectro-polarimetric detection. The demonstrated transparent photodetector concept opens up promising platforms for transparent substrates as the base for opto-electronic devices and in situ optical measurement systems.
关键词： augmented reality,wearable technologies,transparent photodetectors,silicon nanowires,spectro-polarimetric detection
更新于2025-09-12 10:27:22
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Fiber optic sensor based on ZnO nanowires decorated by Au nanoparticles for improved plasmonic biosensor
摘要： Fiber-optic-based localized surface plasmon resonance (FO-LSPR) sensors with three-dimensional (3D) nanostructures have been developed. these sensors were fabricated using zinc oxide (Zno) nanowires and gold nanoparticles (Aunps) for highly sensitive plasmonic biosensing. the main achievements in the development of the biosensors include: (1) an extended sensing area, (2) light trapping effect by nanowires, and (3) a simple optical system based on an optical fiber. The 3D nanostructure was fabricated by growing the ZnO nanowires on the cross-section of optical fibers using hydrothermal synthesis and via immobilization of Aunps on the nanowires. the proposed sensor outputted a linear response according to refractive index changes. The 3D FO-LSPR sensor exhibited an enhanced localized surface plasmon resonance response of 171% for bulk refractive index changes when compared to the two-dimensional (2D) FO-LSPR sensors where the AuNPs are fixed on optical fiber as a monolayer. In addition, the prostate-specific antigen known as a useful biomarker to diagnose prostate cancer was measured with various concentrations in 2D and 3D FO-LSPR sensors, and the limits of detection (LODs) were 2.06 and 0.51 pg/ml, respectively. When compared to the 2D nanostructure, the LOD of the sensor with 3D nanostructure was increased by 404%.
关键词： fiber optic sensor,plasmonic biosensor,Au nanoparticles,localized surface plasmon resonance,ZnO nanowires,FO-LSPR sensors
更新于2025-09-12 10:27:22
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Whispering gallery modes enhance the near-infrared photoresponse of hourglass-shaped silicon nanowire photodiodes
摘要： Silicon photodiodes are widely used in applications that require the measurement of the intensity, colour and position of visible light. Silicon is an attractive material for these systems owing to its low cost, low noise, and easy on-chip integration with read-out electronics. However, silicon cannot effectively be used to detect near-infrared (NIR, at wavelengths of 700–1,000 nm) light and short-wave infrared (SWIR, 1,000–1,700 nm) light because of its bandgap of 1.12 eV, which is equivalent to a wavelength of 1,100 nm. Here, we report silicon photodiodes based on hourglass-shaped silicon nanowires that use whispering-gallery-mode resonances to enhance their photoresponse in the NIR–SWIR region of the spectrum. The upper, inverted nanocone of the nanowires increases absorption probability by extending the dwell time of NIR–SWIR photons via the generation of whispering-gallery-mode resonances, whereas the lower nanocone with its low reflectance reabsorbs the light incident from surrounding nanowires. Our devices exhibit a higher responsivity and external quantum efficiency than existing silicon photodiodes at 700–1,100 nm. Furthermore, the responsivity at 1,000 nm is similar to that of commercial InGaAs photodiodes and light at 1,400 nm can also be detected. Using our devices, we demonstrate a heart-rate measurement system that offers performance comparable to commercial setups.
关键词： silicon photodiodes,whispering-gallery-mode resonances,short-wave infrared,near-infrared,hourglass-shaped silicon nanowires
更新于2025-09-12 10:27:22
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The Growth of Ga2O3 Nanowires on Silicon for Ultraviolet Photodetector
摘要： We investigated the effect of silver catalysts to enhance the growth of Ga2O3 nanowires. The growth of Ga2O3 nanowires on a P+-Si (100) substrate was demonstrated by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of a thin silver film that serves as a catalyst layer. We present the results of morphological, compositional, and electrical characterization of the Ga2O3 nanowires, including the measurements on photoconductance and transient time. Our results show that highly oriented, dense and long Ga2O3 nanowires can be grown directly on the surface of silicon. The Ga2O3 nanowires, with their inherent n-type characteristics formed a pn heterojunction when grown on silicon. The heterojunction showed rectifying characteristics and excellent UV photoresponse.
关键词： electrical conductivity,nanowires,β-Ga2O3,oxidation,silver catalyst,photodetector
更新于2025-09-12 10:27:22
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Self-catalyzed growth of GaSb nanowires for high performance ultraviolet-visible-near infrared photodetectors; 自催化生长GaSb纳米线及其在高性能紫外-可见-近红外光电探测器中的应用;
摘要： A simple self-catalyzed chemical vapor deposition process was conducted to synthesize single-crystalline GaSb nanowires, where Ga droplets were utilized as the catalysts. The as-grown GaSb nanowires exhibited typical p-type semiconductor behavior with the calculated hole mobility of about 0.042 cm2 V?1 s?1. The photoresponse properties of the GaSb nanowires were studied by fabricating nanowire photodetectors on both rigid and flexible substrates. The results revealed that the photodetectors exhibited broad spectral response ranging from ultraviolet, visible, to near-infrared region. For the device on rigid substrate, the corresponding responsivity and the detectivity were calculated to be 3.86×103 A W?1 and 3.15×1013 Jones for 500 nm light, and 7.22×102 A W?1 and 5.90×1012 Jones for 808 nm light, respectively, which were the highest value compared with those of other reported Ga1?xInxAsySb1?y structure nanowires. Besides, the flexible photodetectors not only maintained the comparable good photoresponse properties as the rigid one, but also possessed excellent mechanical flexibility and stability. This study could facilitate the understanding on the fundamental characteristics of self-catalyzed grown GaSb nanowires and the design of functional nano-optoelectronic devices based on Gasb nanowires.
关键词： photoresponse,GaSb nanowires,chemical vapor deposition,mobility,near-infrared,flexible
更新于2025-09-12 10:27:22
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Development of Textured Electrode, Index Matching Layer and Nanostructured Materials for Light Trapping inside Photovoltaic devices
摘要： In order to reduce the energy harvesting cost, numerous efforts have been made to replace crystalline silicon solar cells with thin film based solar cells. The device efficiency of thin film photo-voltaic devices needs to be improved. Currently, surface texturing based light trapping technologies have been used to improve the device efficiency of photo-voltaic devices. In this paper, we demonstrate experimentally that surface textured hydrogenated ZnO:Al films as transparent conducting oxide (TCO) electrode and nanostructured materials in solar cells improve the anti-reflection properties of TCO coated glass substrate. These surfaces scatter the incident light inside the active layer of solar cells. Scattering of light on textured and nanostructured surface causes increase in average light path length inside active layer which results in increased absorption coefficient. Amorphous silicon solar cells fabricated on textured TCO layer show increase in device efficiency. Silicon nitride film was used as index matching layer between glass and TCO and increase in transmittance was observed. Silicon nanowires were grown using PECVD for their application in solar cells. Metal (Indium) nanoparticles were used for plasmonic light trapping inside solar cells. It was observed that textured TCO, index matching layer and plasmonic nanoparticles techniques improve the device efficiency while nanowires based devices need more optimization to get higher efficiency.
关键词： Plasmonic Light Trapping,Nano-Particles,Thin Film Solar Cell,Surface Texturing,Silicon Nanowires
更新于2025-09-12 10:27:22
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Growth Habits of Bismuth Selenide (Bi2Se3) layers and nanowires over Stranski–Krastanov Indium Arsenide Quantum Dots
摘要： Bismuth selenide layers and nanowires have been grown by molecular beam epitaxy on self-assembled Stranski–Krastanov InAs quantum dots of different sizes and densities on GaAs substrates. The size and density of the InAs quantum dots were modified by changes in the growth rate and composition. The structure and growth habits of the Bi2Se3 layers were studied by high-resolution x-ray diffraction, scanning probe microscopy, energy-dispersive x-ray spectroscopy and high-resolution electron microscopy. The epitaxial growth of continuous layers of (0001) Bi2Se3 was observed over flat InAs surfaces. In contrast, the presence of InAs quantum dots induced the growth of 100 nm-long and 20 nm-wide Bi2Se3 nanowires primarily oriented along [01-1] and [0-1-1] directions. The nanowires coalesced into full layers when the growth proceeded further. Better understanding and control of the Bi2Se3 growth habits over these surfaces should lead to novel nanostructures with enhanced physical properties.
关键词： InAs quantum dots,Bi2Se3,nanowires,topological insulator,Bismuth selenide,molecular beam epitaxy
更新于2025-09-12 10:27:22
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Carbon@Tellurium Nanostructures Anchored to a Si Nanowire Scaffold with an Unprecedented Liquid-Junction Solar Cell Performance
摘要： Silicon nanowire (SiNW) arrays offer a range of exciting opportunities, from maximizing solar spectrum utilization for high-performance liquid-junction solar cells (LJSCs) to functioning as potential micro-supercapacitors in the near future. This work, contrasting strongly with the previously reported studies on SiNW-based LJSCs where electron-conducting nanoparticles of Pt or Au were employed to achieve high efficiencies, aims at tethering relatively inexpensive, hole-conducting, and photoresponsive carbon-coated tellurium nanorods (C@TeNRs) to SiNWs in the quest to achieve an outstanding solar cell performance. A SiNW LJSC (control cell) with a SiNWs/Br?, Br2/carbon-fabric architecture delivers a power conversion efficiency (PCE) of 4.8%. Further, by anchoring C@TeNRs, along the lengths of SiNWs via electrophoresis, a PCE of ～11.6% is attained for a C@TeNRs@SiNWs/Br?, Br2/carbon-fabric-based LJSC. The multifunctionality of C@Te comes to the fore in this cell where (1) the p-type (hole) conducting nature of C@Te ensures efficient charge separation by rapidly collecting holes from SiNWs (and suppresses recombination), (2) the C@TeNRs are also photoresponsive and increase light-harvesting, and (3) the C coating restricts the chemical corrosion and photo-oxidation of SiNWs and the Te core by the acidic electrolyte, thereby improving the cell’s operational lifetime. This LJSC also serves as an effective stand-alone energy-storage device giving an improved areal specific capacitance of 1605 μF cm?2 (at 1 mA cm?2). This study unravels the pivotal role played by C@TeNRs in controlling the performance of SiNW-based LJSCs.
关键词： tellurium nanorods,solar cell,liquid junction,high efficiency,silicon nanowires
更新于2025-09-12 10:27:22