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Highly sensitive and selective sensor probe using glucose oxidase/gold nanoparticles/graphene oxide functionalized tapered optical fiber structure for detection of glucose
摘要： A tapered optical fiber structure based glucose sensor using graphene oxide (GO) and gold nanoparticles (AuNPs) is presented in this study. The waist diameter and length of the taper region are 25 μm and 6 mm, respectively. The taper region was created to expose the evanescent waves to the cladding boundaries and to get interact with the external medium. Further, the cladding of tapered region is covered with GO and AuNPs to increase the biocompatibility of sensor and to initiate the phenomenon of localized surface plasmon resonance (LSPR), respectively. The synthesized GO and AuNPs show the good absorbance properties at the peak absorbance wavelengths of 230 nm and 519 nm, respectively. The characterization of synthesized nanomaterials was done by using UV–vis spectrophotometer and TEM. The characterization of nanomaterial coated fiber probe was done by using SEM and SEM-EDS. The specificity of developed sensor probe is enhanced by immobilizing them with the glucose oxidase enzyme, that oxidized only in the presence of glucose solution. The attained results show that the developed sensor model is highly sensitive for the detection of glucose concentrations in human bodies with a sensitivity of 1.06 nm/mM in the linear range of 0 mM–11 mM with the autocorrelation accuracy of 0.9386.
关键词： Localized surface plasmon resonance,Glucose oxidase,Tapered optical fiber,Gold nanoparticles,Glucose,Graphene oxide
更新于2025-09-23 15:21:01
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Boosting Perovskite Photodetector Performance in NIR Using Plasmonic Bowtie Nanoantenna Arrays
摘要： Triple-cation mixed metal halide perovskites are important optoelectronic materials due to their high photon to electron conversion efficiency, low exciton binding energy, and good thermal stability. However, the perovskites have low photon to electron conversion efficiency in near-infrared (NIR) due to their weak intrinsic absorption at longer wavelength, especially near the band edge and over the bandgap wavelength. A plasmonic functionalized perovskite photodetector (PD) is designed and fabricated in this study, in which the perovskite ((Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3) active materials are spin-coated on the surface of Au bowtie nanoantenna (BNA) arrays substrate. Under 785 nm laser illumination, near the bandedge of perovskite, the fabricated BNA-based plasmonic PD exhibits ≈2962% enhancement in the photoresponse over the Si/SiO2-based normal PD. Moreover, the detectivity of the plasmonic PD has a value of 1.5 × 1012 with external quantum efficiency as high as 188.8%, more than 30 times over the normal PD. The strong boosting in the plasmonic PD performance is attributed to the enhanced electric field around BNA arrays through the coupling of localized surface plasmon resonance. The demonstrated BNA-perovskite design can also be used to enhance performance of other optoelectronic devices, and the concept can be extended to other spectral regions with different active materials.
关键词： near infrared,bowtie nanoantenna arrays,perovskite photodetectors,localized surface plasmon resonance
更新于2025-09-23 15:21:01
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Surface Bubble Growth in Plasmonic Nanoparticle Suspension
摘要： Understanding the growth dynamics of the microbubbles produced by plasmonic heating can benefit a wide range of applications like microfluidics, catalysis, micro-patterning and photo-thermal energy conversion. Usually, surface plasmonic bubbles are generated on plasmonic structures pre-deposited on the surface subject to laser heating. In this work, we investigate the growth dynamics of surface microbubbles generated in plasmonic nanoparticle (NP) suspension. We observe much faster bubble growth rates compared to those in pure water with surface plasmonic structures. Our analyses show that the volumetric heating effect around the surface bubble due to the existence of NPs in the suspension is the key to explain this difference. Such volumetric heating increases the temperature around the surface bubble more efficiently compared to surface heating which enhances the expelling of dissolved gas. We also find that the bubble growth rates can be tuned in a very wide range by changing the concentration of NPs, besides laser power and dissolved gas concentration.
关键词： bubble growth dynamics,plasmon resonance,gold nanoparticles (NPs),volumetric heating,micro-bubbles,pulsed laser,photothermal
更新于2025-09-23 15:21:01
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Plasmonic solar cells using mohite Cu2SnS3 nanoparticles
摘要： In this paper, we introduce a new technique for the synthesis of mohite copper tin sulphide (Cu2SnS3) nanoparticles. The method employed is cost effective, non-vacuum, room temperature colloidal synthesis. Here two sulphur sources are used in the synthesis process, sodium sulphide and thioacetamide where the latter is assumed responsible for the mohite crystal structure. The as-prepared sample was characterized using XRD, Laser Raman Spectrometer, SEM/EDS, UV–VIS-NIR spectrophotometer and FTIR spectrophotometer. The sample synthesized appears greenish-black with a metallic lustre. Due to the presence of free electrons on the nanoparticle surface, surface plasmon resonance occurs at 807 nm. Using the uncertainty principle, the plasmon lifetime has been calculated to be 42.5 ns, which is a reasonably longer lifetime, enabling higher photon absorption. Thus mohite copper tin sulphide nanoparticles have a potential application in the absorber layer of low cost plasmonic solar cells.
关键词： Absorber layer,Surface plasmon resonance,Copper tin sulphide,Plasmonic solar cells,Mohite CTS
更新于2025-09-23 15:21:01
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Bacteria functionalized gold nanoparticle matrix based fiber-optic sensor for monitoring heavy metal pollution in water
摘要： In the present study, E.coli B40 bacteria were explored as possible receptors on localized surface plasmon resonance (LSPR) based biosensor for sensing heavy metal ions viz. mercury (Hg2+) and cadmium (Cd2+) in water. The E.coli B40 bacteria were immobilized on gold nanoparticles (AuNP) coated fiber-optic probes by depositing two bi-layers of oppositely charged polyelectrolytes. The E.coli immobilized sensor probes were subjected to different concentrations of Hg2+ and Cd2+ ions, ranging from 0.5 ppb to 2000 ppb. These metal ions interact with the thiols and other surface groups present on the bacterial cells, resulting in the change of refractive index around AuNP coated sensor probes, thereby modulating the sensor response. The detection was performed by spiking de-ionized (DI) water and tap water with metal ions and the limit of detection was found to be 0.5 ppb. The proposed sensor could detect heavy metal ions within 10 min from a small sample (< 1 ml) and showed good selectivity towards heavy metal ions over other transition metal ions. Control studies performed using amino acids like cysteine as receptors were found to be less sensitive than the proposed scheme using bacterial cells.
关键词： polyelectrolytes,fiber-optic sensor,Bacteria,gold nanoparticles,heavy metal ions,localized surface plasmon resonance
更新于2025-09-23 15:21:01
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Tunable Localized Surface Plasmon Resonance and Broadband Visible Photo-response of Cu Nanoparticles/ZnO Surfaces
摘要： Plasmonic Cu nanoparticles (NP) were successfully deposited on ZnO substrates by atomic layer deposition (ALD) owing to the Volmer–Weber island growth mode. An evolution from Cu NP to continuous Cu films was observed with increasing the number of ALD cycles. Real and imaginary parts of the NP dielectric functions, determined by spectroscopic ellipsometry using an effective medium approach, evidence a localized surface plasmon resonance that can be tuned between the visible and near infrared ranges by controlling the interparticle spacing and size of the NP. The resulting Cu NP/ ZnO device shows an enhanced photo-response under white light illumination with good responsivity values, fast response times and stability under dark/light cycles. The significant photocurrent detected for this device is related with the hot electron generation at the NP surface and injection into the conduction band of the ZnO. The possibility of tuning the plasmon resonance together with the photo-responsivity of the device is promising in many applications related with photo-detection, photonics and photovoltaics.
关键词： atomic layer deposition,hot electrons,copper nanoparticles,photodetectors,localized surface plasmon resonance
更新于2025-09-23 15:21:01
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Optimized sample addressing in prism-coupled surface plasmon resonance experiments
摘要： In this work we study the walk-off of the beam from the interrogation spot during rotation in surface plasmon resonance experiments using prism-based coupling such as the widespread Kretschmann configuration. The impossibility of maintaining a stationary footprint on the sensing surface with a fixed rotation axis can be of high importance. This would be specially so if samples are not homogeneous such as in arrays for multiplexing. By theoretically analyzing the behavior of the walk-off during rotation around an arbitrary fixed axis, we find an optimal and simple configuration to minimize this effect. The proposed setup is experimentally tested to verify the results and to show its ease of implementation. Interestingly, the conclusions reached may also be applied to other techniques employing reflection prisms.
关键词： Rotation axis,Surface plasmon resonance (SPR),Alignment optimization,Prism coupling,Walk-off
更新于2025-09-23 15:21:01
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The morphology regulation and plasmonic spectral properties of Au@AuAg yolk-shell nanorods with controlled interior gap
摘要： Au@AuAg yolk-shell nanorods with tunable and uniform interior gap were synthesized through galvanic replacement reaction, where Au@Ag core-shell nanorods served as sacrificial templates and HAuCl4 solution served as reductant. The effects of HAuCl4, Ag shell thickness and aspect ratio (AR) of Au nanorods on the morphology of Au@AuAg yolk-shell nanorods had been investigated systemically. The results clearly indicated that AuAg alloy shell thickness of Au@AuAg yolk-shell nanorods could be increased from 3.6 to 10.0 nm by varying the amount of HAuCl4. Meanwhile, the shape of AuAg alloy shell could be tuned by changing the shape of Ag coating. With the increasing of Ag coating thickness, the interior gap could be finely tuned in the range from 2.6 to 8.1 nm. The uniformity of interior gap could be improved by increasing the AR of Au nanorods. All these tunable geometries can further affect the plasmonic spectral properties of Au@AuAg yolk-shell nanorods. Because of the appearance of interior gap, the longitudinal localized surface plasmon resonance (LSPR) peak of Au@AuAg yolk-shell nanorods was located between that of bare Au nanorods and Au@Ag core-shell nanorods without interior gap. The increase of outer AuAg shell thickness can weaken the coupling between the inner and outer surface of the AuAg shell and lead to the decrease of AR, so the transverse and longitudinal LSPR bands gather together. The decrease of Ag coating thickness can enhance the coupling between inner Au nanorod and outer AuAg shell, which results in the red shift of the longitudinal LSPR band. This paper provides a method for studying the plasmonic coupling between two metal surfaces with a metal layer or a dielectric layer, which is also a new approach for regulating the plasmonic spectral properties of bimetallic nanoparticles. The controllability of Au@AuAg yolk-shell nanorods in both the interior gap and outer alloy shells makes them have potential applications in biomedicine, catalysis, nanoreactors, and energy storage.
关键词： interior gap,localized surface plasmon resonance,spectral properties,morphology regulation,Au@AuAg yolk-shell nanorods
更新于2025-09-23 15:21:01
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High sensitivity surface plasmon resonance sensor based on D-shaped photonic crystal fiber with circular layout
摘要： A high sensitivity D-shaped photonic crystal fiber sensor based on surface plasmon resonance is proposed for refractive index sensing. By using finite element method, the sensing properties of the proposed sensor are investigated. The numerical results show a very high average sensitivity of 14600 nm/RIU with the high resolution of 6.80 × 10?6 RIU for refractive index (RI) of analytes ranging from 1.420 to 1.435. The layout of the air holes is designed to be circular and only two layers in this D-shaped photonic crystal fiber. The metallic gold is used as the surface plasmon resonance activity material, which is deposited on the polishing surface. The analyte is placed on the outer layer of the D-shaped photonic crystal fiber. This D-shaped photonic crystal fiber solves the difficulty of gold-plated film and fill analyte in the holes. The proposed PCF structure is a combination of circular layout and D-shaped, which also leads to the proposed sensor easy to fabricate and has considerable sensitivity.
关键词： Sensitivity,Photonic crystal fiber,Refractive index sensor,Surface plasmon resonance
更新于2025-09-23 15:21:01
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Three-core photonic crystal fiber surface plasmon resonance sensor
摘要： A three-core photonic crystal fiber (PCF) surface plasmon resonance (SPR) biosensor with high performance is presented. The structure of the biosensor is easy to implement and has good repetition. The outer layer of the fiber structure is gold film. The analyte is placed on the surface of the gold film. The Full vector finite element method is used to numerical simulation and analysis the transmission mode and characteristics of the three-core PCF-SPR biosensor. The influence of sensor structure parameters on sensing performance is investigated. The structure parameters are optimized. The optimum structure parameters are given. The refractive index (RI) sensitivity of the sensor is discussed there. The results show that the average refractive index sensitivity of the sensor is 3435 nm/RIU in the sensing range of 1.33–1.40, and the resolution is 2.91 × 10?6 RIU. The sensor has the advantages of high sensitivity and high resolution. And it can be applied to real-time detection of the bio-molecules and small drug-molecules.
关键词： Photonic crystal fiber,Biosensor,Surface plasmon resonance,Refractive index sensitivity,Finite element method
更新于2025-09-23 15:21:01