Plasmon Resonance Of Nanoparticles Research Articles

Fermi-level shift, electron separation, and plasmon resonance change in Ag nanoparticle-decorated TiO2 under UV light illumination.

Noble metal nanoparticles are widely used as co-catalysts for storing and separating electrons in semiconductor photocatalysis. Thus, evaluating this ability is important and meaningful to understand the photocatalytic mechanism. Employing Ag nanoparticles, the present study combined in situ photoconductance and theoretical analysis to evaluate the Fermi-level (EF) shift in a UV-illuminated Ag/TiO2 system under gaseous conditions. Based on this, the role of the Ag nanoparticles in storing and separating electrons was discussed. It was found that the EF of Ag/TiO2 is located deeper in the gap and a variation in temperature has less effect on the EF of Ag/TiO2 compared to the undecorated TiO2. The analysis showed that ∼46 electrons can be stored in 10 nm Ag nanoparticles under our experimental conditions, which does not change with temperature. The electron traps in TiO2 can affect the electron distribution in the TiO2 and Ag nanoparticles. It was observed that the localized surface plasmon resonance (LSPR) of the Ag nanoparticles exhibited a blue-shift under UV light illumination, which is generally ascribed to the electron storage in the Ag nanoparticles. However, we showed that the blue-shift is not related to the electron storage in the Ag nanoparticles, and thus it cannot be used as an indicator for evaluating their electron-storage ability. The in situ XPS analysis also does not support that the LSPR blue shift is associated with the reduction in the Ag2O layer and TiO2.

Solvent-induced local environment effect in plasmonic catalysis.

Solvents are known to affect the local surface plasmon resonance of metal nanoparticles; however, how solvents can be used to manipulate the interfacial charge and energy transfer in plasmonic catalysis remains to be explored. Here, using NH3 decomposition on a Ru-doped Cu surface as an example, we report density functional theory (DFT) and delta self-consistent field (SCF) calculations, through which we investigate the effect of different protic solvent molecules on interfacial charge transfer by calculating excitation energy of an electronic transition between the metal and the molecular reactant. We find that the H-bonds between water and NH3 can alter the direct interfacial charge transfer due to the shift of the molecular frontier orbitals with respect to the metal Fermi level. These effects are also observed when the H-bonds are formed between methanol (or phenol) and ammonia. We show that the solvent possessing stronger basicity induces a more pronounced effect on the excitation energy. This work thus provides valuable insights for tuning the excitation energy and controlling different routes to channel the photon energy into plasmonic catalysis.

Surface lattice resonance effect of double-ring array of metallic nano-particles

Surface lattice resonances due to regular periodic array of metallic nanoparticles can be attributed to the mutual coupling between the localized surface plasmon resonances of different nanoparticles. A comparison of resonant effect between the single particle and the array shows that the resonance line width can be significantly reduced. In this paper, we extend the coupled dipole approximation to solving the electromagnetic characteristics of the particle ring structures with rotational symmetry, and propose an analytical model for the double ring array of metallic nano-particles. Furthermore, we derive the general resonant condition of the double ring array and investigate some concrete cases in detail. It shows that the full resonance of the whole array depends crucially on the structural parameters, whose enhancement factor can be extremely high. But a slight change in the structural parameter willlead the enhancement factor to decrease sharply. We also find that the radiation field of the full resonance effect will be independent of the external field, which provides us a simple approach to producing a localized optical field with complex space distribution. This proposed structure can possess potential applications in various fields such as metasurface, optoelectronics, optical manipulation, communication, and biosensing.

Формирование олигомеров серебряных наночастиц, полученных методом лазерной абляции в жидкости, путем последовательного центрифугирования и ультрасонификации: управляемый длинноволновый сдвиг плазмонного резонанса в интересах биомедицинских применений

A relatively simple physical method has been proposed for fabrication of stable oligomers of silver nanoparticles, preliminarily obtained by pulsed laser ablation of a metal target in a liquid. Oligomers of silver nanoparticles are formed in an aqueous solution after prolonged centrifugation at 18000 g and subsequent ultrasonification of the initial colloidal solution of spherical nanoparticles obtained by laser ablation. The plasmon resonance in oligomers is shifted relative to the plasmon resonance in spherical nanoparticles to the long wavelength region by 140 nm.

Metallic plasmons significantly boosted visible-light photocatalytic hydrogen evolution from water splitting

Surface plasmon resonance (SPR) of Ni nanoparticles has been studied to promote the generation of hot electrons, charge transfer and separation over g-C3N4/Ni@C plasmonic photocatalysts, resulting in boosted visible-light photocatalytic H2 evolution from water splitting.

Мониторинг локализованного плазмонного резонанса неоднородного ансамбля серебряных наночастиц на границе двух сред

Optical properties of an inhomogeneous ensemble of plasmonic silver nanoparticles obtained by thermal vacuum deposition at the interface between two media as this interface moves relative to the nanoparticles themselves have been studied. The movement was carried out due to thermally stimulated diffusion of nanoparticles into the polystyrene layer and due to the deposition of an additional layer of quartz on a granular film with nanoparticles on a quartz substrate. The frequency shifts of the inhomogeneous plasmon resonance of nanoparticles moving through the interface was to about two tens of nanometers.

Au Nanoparticles (NPs) Decorated Co Doped ZnO Semiconductor (Co400-ZnO/Au) Nanocomposites for Novel SERS Substrates.

Au nanoparticles were decorated on the surface of Co-doped ZnO with a certain ratio of Co2+/Co3+ to obtain a novel semiconductor-metal composite. The optimal substrate, designated as Co400-ZnO/Au, is beneficial to the promotion of separation efficiency of electron and hole in a semiconductor excited under visible laser exposure, which the enhances localized surface plasmon resonance (LSPR) of the Au nanoparticles. As an interesting finding, during Co doping, quantum dots of ZnO are generated, which strengthen the strong semiconductor metal interaction (SSSMI) effect. Eventually, the synergistic effect effectively advances the surface enhancement Raman scattering (SERS) performance of Co400-ZnO/Au composite. The enhancement mechanism is addressed in-depth by morphologic characterization, UV-visible, X-ray diffraction, photoluminescence, X-ray photoelectron spectroscopy, density functional theory, and finite difference time domain (FDTD) simulations. By using Co400-ZnO/Au, SERS detection of Rhodamine 6G presents a limit of detection (LOD) of 1 × 10-9 M. As a real application, the Co400-ZnO/Au-based SERS method is utilized to inspect tyramine in beer and the detectable concentration of 1 × 10-8 M is achieved. In this work, the doping strategy is expected to realize a quantum effect, triggering a SSSMI effect for developing promising SERS substrates in future.

Self-cleaning application of mesoporous ZnO, TiO2 and Fe2O3 films with the accommodation of silver nanoparticles for antibacterial activity

BackgroundThe infections spread in healthcare circumstances is a growing and persistent issue worldwide, motivated by the development of microbial durability to disinfectants and antibiotics. Self-cleaning or disinfecting is one of the most attractive and promising technologies for glass windows, buildings, operating rooms, and hospitals. MethodThe transparent films of mesoporous TiO2, ZnO and Fe2O3 with different layers were synthesized and coated with silver nanoparticles through the sol-gel technique. The contact angles of the Ag/ZnO, Ag/TiO2 or Ag/Fe2O3 films were found to be less than 10°, indicating the obtained films were superhydrophilic. These films were tested for their disinfection ability for different bacteria species under direct light illumination. Significant FindingsResults have shown that Ag/TiO2 exhibited strong anti-bactericidal performances, and the Ag/TiO2 1-layer (1L), 2-layer (2L) and 3-layer (3L) films were the best of all treatments producing consistently higher antibacterial activity with Vibrio parahaemolyticus, Aeromonas hydrophila, and Bacillus subtilis in the reducing order of efficacy. The exposure time of 3 h was sufficient to reduce the cell counts of bacterial strains. The reason behind the higher antibacterial activity of Ag/TiO2, Ag/ZnO and Ag/Fe2O3 films compared with pristine ZnO, Fe2O3 and TiO2 films might be the surface plasmon resonance of Ag nanoparticles. The small Ag clusters create sinks for electrons, thus expediting the photoinduced electron- holes separation and enhancing the antibacterial activity. Therefore, the highest antibacterial activity observed for the Ag/TiO2 films was referred to as the most effective separation of charge carriers during the fast charge transfer.

Near field and far field plasmonic enhancements with bilayers of different dimensions AgNPs@DLC for improved current density in silicon solar

The effect of a bilayer of different dimension silver nanoparticles (Ag NPs) on light trapping in silicon solar cells is investigated. Here, we report on the improved performance of silicon solar cells by integrating two layers of silver nanoparticles of different sizes. We experimentally examine the plasmonic near-field and far-field effects of bilayer Ag NPs embedded within an anti-reflective DLC layer on silicon solar cells' optical and electrical characteristics. Field-Emission Scanning Electron Microscopy drove the two-dimensional differences in the size of Ag NPs. The surface plasmon resonance of the two-dimensional nanoparticles was estimated from the absorption optical spectra. External quantum efficiency measurements showed that near-field or far-field plasmonic effects altered with the Ag NPs size. The development of far fields was confirmed by measuring the solar cell performance under AM 1.5 G illumination. The impact of the far-field in the cell containing two layers of Ag NPs, which outer layer is larger dimensions NPs, improves the current density up to 38.4 mA/cm2 (by 70% compared to the bare reference cell).

Regioselective Plasmon-Driven Decarboxylation of Mercaptobenzoic Acids Triggered by Distinct Reactive Oxygen Species

The non-radiative decay of surface plasmon resonance (SPR) in plasmonic metal nanoparticles (NPs) opens up unique hot-carrier-driven chemical transformation mechanisms. Here, the hot-carrier generation of reactive oxygen species was demonstrated to trigger the regioselective plasmon-driven decarboxylation of mercaptobenzoic acid (MBA) isomers over Ag (AgNPs) and Au nanoparticles (AuNPs). Controlled catalytic experiments indicated that the catalytic C–C bond cleavage over AgNPs and AuNPs is primarily initiated by photogenerated singlet oxygen (1O2) and hydroxyl radical (•OH), respectively. Energetic hot electrons on AgNPs can successfully generate 1O2 from 3O2 via Dexter energy transfer, while hot holes generated under the Fermi level of AuNPs have sufficient energy to oxidize OH– and promote the formation of reactive •OH. The catalytic activity trend was evaluated considering the known ortho-substituent effect. The data discussed herein shed light on how the intrinsic differences in electronic energy levels and metal–molecule interactions precisely tune the regioselectivity of plasmon-driven transformations and may guide the rational design of plasmonic catalysts for distinct desired reactions.

Dual mode fluorometric and colorimetric detection of matrix metalloproteinase MMP-9 as a cancer biomarker based on AuNPs@gelatin/AuNCs nanocomposite

Matrix metalloproteinase (MMPs) are proteolytic enzymes which considered as important enzymes and their higher expression is associated with some malignant progression. In the present study, a novel and sensitive method was developed for detection of MMP-9 based on its gelatinase activity. Green emitting gold nanoclusters (AuNCs) has been synthesized by gelatin substrate and then AuNPs@gelatin/AuNCs nanocomposite structure were prepared through coating of gold nanoparticles (AuNPs) with gelatin/AuNCs. Characterization and morphology of synthesized nanocomposite showed successful formation of AuNPs@gelatin/AuNCs. Constructed nanocomposite exhibited internal FRET occurrence and fluorescence quenching of AuNCs due to proximity of AuNCs/AuNPs structures. Hydrolysis effect of MMPs enzyme on AuNPs@gelatin/AuNCs in saline buffer induced changes in surface plasmon resonance (SPR) of gold nanoparticles and also enhanced the emitted fluorescence by AuNCs due to inhibition of internal FRET process. The proposed platform served as the efficient approach for semi-quantitative detection of MMP-9 enzyme by naked eye and precise activity detection with LOD of 2 ng/mL calorimetrically and 0.25 ng/mL fluorometrically. The approach was also showed convenient recovery for detection of MMP-9 enzyme in human serum matrix. Our work provides an efficient, convenient and practical tool for simple identification and precise detection of MMP-9 enzyme.

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Surface and Interface AnalysisVolume 55, Issue 2 p. 162-162 ERRATUMFree Access ERRATUM This article corrects the following: Gamma irradiation induced surface plasmon resonance of Cu nanoparticles in fullerene C60 Jyotsna Bhardwaj, Ritu Vishnoi, Amena Salim, Shriniwas Yadav, Sunil Ojha, Umesh Dwivedi, Asokan Kandasami, Pushpendra Kumar, Ganesh D. Sharma, Rahul Singhal, Volume 54Issue 11Surface and Interface Analysis pages: 1130-1141 First Published online: July 30, 2022 First published: 03 November 2022 https://doi.org/10.1002/sia.7168AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Gamma irradiation induced surface plasmon resonance of Cu nanoparticles in fullerene C60 In Bhardwaj et al,1 the name of the ninth author was misspelled in the original published article. The name “Ghanshyam Dutt Sharma” should have read as “Ganesh D. Sharma”. REFERENCE 1Bhardwaj J, Vishnoi R, Salim A, et al. Gamma irradiation induced surface plasmon resonance of Cu nanoparticles in fullerene C60. Surf Interface Anal. 2022; 54(11): 1130- 1141. doi:10.1002/sia.7137 Volume55, Issue2February 2023Pages 162-162 ReferencesRelatedInformation

Effect of plasmonic metal (Cu, Ag, and Au) loading over the physicochemical and photocatalytic properties of Mg-Al LDH towards degradation of tetracycline under LED light

This work focused on the enhancement of the photocatalytic activity of solvothermal synthesized Mg0.667 Al0.333 (OH)2 (CO3)0.167 (H2O)0.5 layered double hydroxide (LDH) by plasmonic metal (Cu, Ag, and Au) photodeposition (1-3 wt%). HRTEM analysis confirmed the successful loading of plasmonic nanoparticles with varying sizes (Au (∼4–25 nm) > Ag (∼3–12 nm) > Cu (∼2–7 nm)) on the surface of LDH. The effect of different plasmonic metals and their size on the surface structural, optical, electrokinetic, and photocatalytic properties of LDH was investigated. The prepared catalysts were evaluated for the degradation of tetracycline under LED irradiation for 140 min and the photoactivity trend followed the order: pristine LDH < Cu@LDH < Ag@LDH < Au@LDH. The LC-MS studies revealed that the degradation occurred by the attack of various reactive species (O2.-, h+, OḢ) via four paths mainly including hydroxylation, functional group cleavage, and ring-opening reaction. A possible mechanism was proposed for the appreciable enhancement in performance caused by the formation of Schottky barriers and surface plasmon resonance of plasmonic nanoparticles. The results of total organic carbon (TOC) indicated the acceptable mineralization of about 84 %. Less than a 10 % fall in degradation efficiency was observed within four recycle runs.

Green Synthesis and characterization of Lead Oxide Nanoparticles using Piper Betle leaf

Lead oxide nanoparticles were synthesized by using cost effective and eco friendly green method assisted by piper betle leaf extract. The UV absorption spectrophotometer analysis of leaf extract and metal compounds showed absorbance spectra in the range 300-400 nm. The UV-Vis spectroscopy shows Surface Plasmon resonance of PbO nanoparticles at 320 nm indicating that the particles are poly dispersed. The FT-IR measurements were carried out to identify the formation of lead oxide nanoparticles and possible molecules such as OH, C=C, C=O and aromatic compounds. The FT-IR analysis played a pivoted role in displaying the nanoparticles which showed strong absorbance in the range 518-600 cm-1 for lead oxide nanoparticles. The diffraction peaks and planes of ions are indexed. From the ‘X’ ray diffraction analysis, the size of the lead oxide nanoparticles is 70 nm as calculated by Debye scherrer’s equation. The size, shape and structure of nanoparticles were also analyzed by Scanning electron microscope showing tetragonal shape of nanoparticles aggregation. This green synthesis method has many advantages over the chemical method because it reduces the use of toxic metals in the synthesis process.

Advances in Novel Nanomaterial-Based Optical Fiber Biosensors-A Review.

This article presents a concise summary of current advancements in novel nanomaterial-based optical fiber biosensors. The beneficial optical and biological properties of nanomaterials, such as nanoparticle size-dependent signal amplification, plasmon resonance, and charge-transfer capabilities, are widely used in biosensing applications. Due to the biocompatibility and bioreceptor combination, the nanomaterials enhance the sensitivity, limit of detection, specificity, and response time of sensing probes, as well as the signal-to-noise ratio of fiber optic biosensing platforms. This has established a practical method for improving the performance of fiber optic biosensors. With the aforementioned outstanding nanomaterial properties, the development of fiber optic biosensors has been efficiently promoted. This paper reviews the application of numerous novel nanomaterials in the field of optical fiber biosensing and provides a brief explanation of the fiber sensing mechanism.

Photoluminescence sensing of Pb2+ using cellulose acetate nanofiber decorated with Au nanoparticles

Lead (II) is the second most hazardous heavy metal to the environment and humanity, due to its accumulation in the food chain and remaining as a persistent toxin in the environment. Thus, the design and fabrication of effective sensing materials and devices for the speedy detection of lead is a great challenge. Herein, we introduce gold nanoparticles deposited on the surface of electrospun cellulose acetate nanofiber Au@CANFs as photoluminescence sensor for detecting trace amount of lead metal ions based on a photoluminescence quenching approach. Despite that the concentration of cellulose acetate used for fabrication of nanofiber is lower than that previously reported, we observed nanofiber with small diameter and uniform shape. The scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis of the as-prepared sensor reveal the formation of nanofiber structure with diameter 90–200 nm and Au NPs are distributed on the surface of nanofiber with size 15–50 nm. The surface structure and chemical compositions of Au@CANFs were performed by Fourier transform infrared (FTIR) and XPS techniques. The UV-Vis spectra, clearly demonstrating that the sensor displayed localized surface plasmon resonance (LSPR) of Au nanoparticles. Both photoluminescence spectroscopy and Inverted Fluorescence microscopy image demonstrating that the CANFs and Au@CANFs display green emission. Under optimum conditions, the Au@CANFs PL sensor showed high sensitivity for detection of Pb2+ ion within a working range of 0 μg/L to 6 μg/L, R2 = 0.992 and a limit of detection of 0.16 ppb. Based on the obtained results, we anticipate that this PL sensor can be easily extended to tune the sensing performance of different heavy metals.

Synthesis and synergistic effect of antibacterial composites based on concentrated hydrosols of silver nanoparticles combined with cephalosporins antibiotics

Silver nanoparticles may be used as potential antimicrobial agents. Concentrated silver nanoparticles (AgNPs) were synthesised by the Carey Lee method. Then, antibiotics, such as disodium ceftriaxone, sodium cefotaxime, sodium cefazolin and sodium cefoperazone, were added to the AgNPs at the ratio of AgNPs:antibiotic = 5:1. The concentrated hydrosols were examined using UV–Vis, FTIR-spectroscopy, dynamic light scattering and transmission electron microscopy. The spectra plasmon resonance of silver nanoparticles and their combination with antibiotics had a single strong peak at 412–415 nm. The transmission electron microscopy micrographs showed different forms. The average size of AgNPs-antibiotic particles was smaller than that of AgNPs. The antibacterial activities of AgNPs, antibiotics and AgNPs-antibiotics were determined by the disk diffusion method against Staphylococcus aureus and Escherichia coli. The most significant enhancement of the antibacterial effect over the antibiotic was demonstrated by AgNPs-disodium ceftriaxone against E.coli. Also, the minimal inhibitory concentration (MIC) of the AgNPs-antibiotics was defined. All the AgNPs-antibiotic exhibited a synergistic enhancement by AgNPs and the antibiotic of antibacterial activity. A possible explanation of this phenomenon was proposed. Our results suggest that the synthesis of the concentrated hydrosol of the AgNPs-antibiotics is essential for studying similar nanosystems.

Performance of graphene/P-InP Schottky diode enhanced by silver nanoparticles

In this paper, a Schottky junction near-infrared photodetector is formed by the combination of two-dimensional(2D) material graphene and P-InP. By using the surface plasmon resonance of silver nanoparticles(Ag NPs), a layer of Ag NPs was spin-coated on the single-layer graphene(SLG)/P-InP structure to improve the response rate. As a result, the response rate and detection rate were improved, and the response rate was increased from 1.227 mA/W to 7.876 mA/W, the detection rate was also increased from 5.052 × 109 cmHz1/2W−1 to 1.178 × 1010 cmHz1/2W−1. Since the defects and dangling bonds on the semiconductor surface can be reduced by depositing a thin oxide layer between graphene and semiconductor as a passivation layer, a 2 nm Al2O3 layer was inserted between graphene and P-InP to form Ag NPs/SLG/Al2O3/P-InP structure. The Schottky barrier height was increased from 0.675 eV to 0.815 eV, the response rate was further greatly improved, up to 40.195 mA/W, and the detection rate was also increased to 6.08 × 1010 cmHz1/2W−1.

Fitting Procedure to Reconstruct the Size Distribution and the Concentration of Silver Colloidal Nanoparticles from UV-Vis Spectra.

In this work, a complete fitting procedure of UV-Vis spectra of silver nanoparticles in colloidal solutions is reported. The fitting function, based on the Beer–Lambert law, Mie theory, and log-normal probability distribution of nanoparticles’ sizes, is developed and confirmed by 33 different independent measurements. In order to validate the accuracy of the function’s behavior on different spectra, freely accessible measurements were used, proving that the fitting function works independently of the method of their production—laser or chemical synthesis of nanoparticles. The developed fitting function is, to the best of our knowledge, novel and not based on any conventional spectral analysis approaches like the Mie–Gans procedure. Furthermore, since fitted parameters are all physical, it allows determination of the mode diameter of nanoparticles as well as the standard deviation of the log-normal distribution of sizes. It enables the reconstruction of size distribution of nanoparticles in colloidal solution. Step-by-step derivation of the fitting function is provided with a physical explanation of all parameters. The importance of Lorentzian dependence emerging at the core of Beer–Lambert law is physically discussed and linked to harmonic oscillator behavior of localized surface plasmon resonance of silver nanoparticles in a colloidal solution. Size distribution reconstruction from fitted parameters according to a log-normal distribution function is provided and a concentration calculation is presented.

Local control of optical absorption properties of glass using precipitation of gold nanoparticles via gold sphere movement driven by laser

Glass embedded with metal nanoparticles is a promising material necessary for optical devices because of its absorption properties associated with the surface plasmon resonance (SPR) of metal nanoparticles. We demonstrated that continuous-wave laser illumination of the metal sphere in glass migrates the metal sphere and dopes the migration trajectory. In this study, we have attempted to locally control the absorption properties of borosilicate glass via gold nanoparticle precipitation using gold sphere migration. The gold sphere was moved in the glass via laser illumination, and the gold nanoparticles were precipitated in the movement trajectory. The trajectory was colored in red and purple gradations because of the SPR of gold nanoparticles. The particle size of the precipitated gold nanoparticles and the absorption peak wavelength increased with increasing velocity of the gold sphere. The absorption properties of the trajectory depend on the velocity of the gold sphere migration, which enabled local control of the absorption properties of the glass.