Surface Plasmon Resonance Effect Research Articles

Plasmonic Near-Infrared-Response S-Scheme ZnO/CuInS2 Photocatalyst for H2O2 Production Coupled with Glycerin Oxidation.

Solar fuel synthesis is intriguing because solar energy is abundant and this method compensates for its intermittency. However, most photocatalysts can only absorb UV-to-visible light, while near-infrared light remains unexploited. Surprisingly, the charge transfer between ZnO and CuInS2 quantum dots (QDs) can transform a near-infrared-inactive ZnO into a near-infrared-active composite. This strong response is attributed to the increased concentration of free charge carriers in the p-type semiconductor at the interface after the charge migration between ZnO and CuInS2, enhancing the localized surface plasmon resonance effect and the near-infrared (NIR) response of CuInS2. As a paradigm, this ZnO/CuInS2 heterojunction is used for H2O2 production coupled with glycerin oxidation and demonstrates supreme performance, corroborating the importance of near-infrared response and efficient charge transfer. Mechanistic studies through contact potential difference, Hall effect test, and finite element method calculation allow for the direct correlation between the near-infrared response and charge transfer. Our approach bypasses the general light response issues, thereby stepping forward to the ambitious goal of harnessing the entire solar spectrum. This article is protected by copyright. All rights reserved.

Achieving Visible Light Triggered Overall Water Splitting over Plasmonic Au/SrTiO3:Al Photocatalyst

AbstractThe surface plasmon resonance (SPR) effect has garnered extensive attention in semiconductor photocatalysis for solar energy conversion, thanks to its remarkable optical properties. However, the majority SPR‐induced photocatalytic systems have been limited to achieving hydrogen evolution or oxygen evolution half reactions, and attaining overall water splitting on a SPR‐induced photocatalyst under visible light remains a formidable challenging. In this study, we employed a plasmonic photocatalyst Au/SrTiO3, and further enhanced its performance by doping aluminum (Al) into the SrTiO3 lattice (denoted as Au/SrTiO3:Al). By constructing reduction cocatalyst (RhCrOx) and oxidation cocatalyst (CoOOH), the Au/SrTiO3:Al photocatalyst successfully realizes photocatalytic overall water splitting with a stoichiometric ratio of H2 and O2 under visible light (λ≥440 nm). We revealed that the introduction of Al species effectively modified the electronic structure of SrTiO3, thereby enhancing the hydrogen evolution reaction in Au/SrTiO3:Al. Simultaneously, the RhCrOx and CoOOH cocatalysts synergistically capitalized on the short‐lived hot electrons and holes generated by the plasmonic Au/SrTiO3:Al photocatalyst, enabling to realize photocatalytic overall water splitting. This work offers a promising avenue for the rational design of plasmon‐induced overall water splitting photocatalysts through the integration of suitable cocatalysts and surface/interface engineering strategies.

Synthesis of 3D Sb2O3-based heterojunction reinforced by SPR effect and photo-Fenton mechanism for upgraded oxidation of metronidazole in water environments

The traditional homogenous and heterogenous Fenton reactions have frequently been restrained by the lower production of Fe2+ ions, which significantly obstructs the generation of hydroxyl radicals from the decomposition of H2O2. Thus, we introduce novel photo-Fenton-assisted plasmonic heterojunctions by immobilizing Fe3O4 and Bi nanoparticles onto 3D Sb2O3 via co-precipitation and solvothermal approaches. The ternary Sb2O3/Fe3O4/Bi composites offered boosted photo-Fenton behavior with a metronidazole (MNZ) oxidation efficiency of 92% within 60 min. Among all composites, the Sb2O3/Fe3O4/Bi-5% hybrid exhibited an optimum photo-Fenton MNZ reaction constant of 0.03682 min− 1, which is 5.03 and 2.39 times higher than pure Sb2O3 and Sb2O3/Fe3O4, respectively. The upgraded oxidation activity was connected to the complementary outcomes between the photo-Fenton behavior of Sb2O3/Fe3O4 and the plasmonic effect of Bi NPs. The regular assembly of Fe3O4 and Bi NPs enhances the surface area and stability of Sb2O3/Fe3O4/Bi. Moreover, the limited absorption spectra of Sb2O3 were extended into solar radiation by the Fe3+ defect of Fe3O4 NPs and the surface plasmon resonance (SPR) effect of Bi NPs. The photo-Fenton mechanism suggests that the co-existence of Fe3O4/Bi NPs acts as electron acceptor/donor, respectively, which reduces recombination losses, prolongs the lifetime of photocarriers, and produces more reactive species, stimulating the overall photo-Fenton reactions. On the other hand, the photo-Fenton activity of MNZ antibiotics was optimized under different experimental conditions, including catalyst loading, solution pH, initial MNZ concentrations, anions, and real water environments. Besides, the trapping outcomes verified the vital participation of •OH, h+, and •O2− in the MNZ destruction over Sb2O3/Fe3O4/Bi-5%. In summary, this work excites novel perspectives in developing boosted photosystems through integrating the photocatalysis power with both Fenton reactions and the SPR effects of plasmonic materials.

A Schottky heterojunction with spatially separated active sites for piezo-photocatalytic dual-channel hydrogen peroxide generation

Mechanical and solar energy-driven piezo-photocatalysis has drawn growing attention for H2O2 synthesis and related applications. However, most reported works focused on single pathway and ignored simultaneous oxygen reduction and water oxidation for H2O2 generation. Herein, Au-ZnO Schottky heterojunction is constructed for piezo-photocatalytic H2O2 synthesis via dual-channel pathway (simultaneous oxygen reduction and water oxidation). Experimental results and density functional theory calculations illustrated that the reduction and oxidation reactions predominantly take place at Au and ZnO sites, respectively. The spatially separated active sites avoid site competition, and enable a synergistic effect of oxidation and reduction. Furthermore, Au nanoparticles not only provide hot electrons via surface plasmon resonance effect, but also form Schottky junctions with ZnO to decrease the charge shielding effect. As a result, a H2O2 generation of 186 μM in pure water (30 min) is achieved by the optimal sample. This study provides a strategy for the construction of piezo-photocatalysts from the perspective of spatially separated redox sites for efficient H2O2 synthesis.

Lamellar copper molybdate as a novel photocatalyst for the degradation of Rhodamine B

Water containing organic pollutants poses increasingly severe challenges to the clean water resources that humans rely on for survival. Photocatalysis is one of the technologies for removing organic pollutants from wastewater, which is green and has no secondary pollution. Here layered HCu1.5MoO5 photocatalyst is synthesized by wet chemistry. It is assembled from multiple stacked thin nanosheets with a thickness of ∼ 12.5 nm. The thin-layer structure of two-dimensional photocatalysts considerably reduces the migration distance of photo-generated charge carriers, thereby promoting efficient charge separation. In addition, it exhibits near-ultraviolet light response with the remarkable local surface plasmon resonance (LSPR) effect in the visible light region. The specific surface area and mesoporous structure of HCu1.5MoO5 are particularly advantageous for the mass transfer process of photocatalytic degradation. These characteristics enable it to effectively degrade Rhodamine B, achieving a degradation rate of 78.4 % after 120 min. The work provides a new perspective for the development of layered photocatalysts for photocatalytic degradation.

Improved photoelectrochemical performance of TiO2-in-MIL-101(Cr)@CDs@AgNPs and application for the detection of ultralow level AβO

TiO2 was successfully synthesized within the internal pores of MIL-101(Cr), leading to the formation of a TiO2-in-MIL-101(Cr) composite. This heterojunction structure significantly improved the photogenerated electron-hole separation within the metal-organic framework (MOF) composite. Subsequently, carbon dots (CDs) and silver nanoparticles (AgNPs) were introduced to further modify the TiO2-in-MIL-101(Cr), resulting in a multimodified MIL-101(Cr) composite. The integration of CDs enhanced the light absorption capabilities of the composite, thereby boosting the photocurrent. Meanwhile, AgNPs not only enhanced the absorption of visible light through the local surface plasmon resonance effect (LSPR) but also facilitated efficient electron transport. This multimodal modification strategy led to a remarkable enhancement in the photoelectrochemical (PEC) performance of MIL-101(Cr), with the photocurrent density (J) increasing by approximately a factor of 19. To further expand the functionality of this composite, AβO capture DNA (cDNA) and CuS-binding aptamer were grafted onto the TiO2-in-MIL-101(Cr)@CDs@AgNPs, creating a sandwich-like structure. Based on this multimodified MIL-101(Cr) composite, an "on-off-on" type PEC biosensor was constructed. The p-type semiconductor CuS served as a signal amplifier, capturing photogenerated electrons and effectively reducing the photocurrent. When cDNA hybridized with AβO, the Apt-CuS moiety detached from the MIL-101(Cr) composite, leading to the restoration of the photocurrent. The PEC biosensor for the detection of AβO exhibited optimal performance at a pH of 7.00, an incubation temperature of 37 °C, and an incubation time of 45 min. Under these conditions, the biosensor demonstrated a wide detection range of 5 fM to 1 μM, with an ultralow detection limit of 4.36 fM. This method exhibits high sensitivity, robust anti-interference capabilities, and holds great promise for applications in tracing the detection of AβO in human serum.

D-shaped photonic crystal fiber based on surface plasmon resonance for low refractive index applications

Here, a fresh D-type photonic crystal fiber has been developed by us, relying on the surface plasmon resonance effect. Differing from conventional D-type photonic crystal fiber, this model coats gold film on an open-loop channel for excitation. Through the finite element method analysis, this sensor exhibits an effective scope of 1.20–1.30 for the refractive index of analyte. As the RI of the analyte rises, the loss peak within the spectrum gradually intensifies and then remains stable. At an RI value of 1.30, achieving a resolution of 9.52 × 10−6 RIU, this sensor exhibits excellent performance with a maximum sensitivity of 10,500 nm/RIU. Its simple structure adds to its overall appeal. The outstanding sensing performance demonstrates enhanced competitiveness in sectors with lower refractive indices. Farther, to enhance the sensor's sensing capabilities, we conducted an analysis of how structural parameters impact the resonance spectrum with the goal of optimization.

SERS Detection of Trace Carcinogenic Aromatic Amines Based on Amorphous MoO3 Monolayers.

Aromatic amines are important commercial chemicals, but their carcinogenicity poses a threat to humans and other organisms, making their rapid quantitative detection increasingly urgent. Here, amorphous MoO3 (a-MoO3) monolayers with localized surface plasmon resonance (LSPR) effect in the visible region are designed for the trace detection of carcinogenic aromatic amine molecules. The hot-electron fast decay component of a-MoO3 decreases from 301 fs to 150 fs after absorption with methyl orange (MO) molecules, indicating the plasmon-induced hot-electron transfer (PIHET) process from a-MoO3 to MO. Therefore, a-MoO3 monolayers present high SERS performance due to the synergistic effect of electromagnetic enhancement (EM) and PIHET, proposing the EM-PIHET synergistic mechanism in a-MoO3. In addition, a-MoO3 possesses higher electron delocalization and electronic state density than crystal MoO3 (c-MoO3), which is conducive to the PIHET. The limit of detection (LOD) for o-aminoazotoluene (o-AAT) is 10-9 M with good uniformity, acid resistance, and thermal stability. In this work, trace detection and identification of various carcinogenic aromatic amines based on a-MoO3 monolayers is realized, which is of great significance for reducing cancer infection rates.

Synergistic effect between ohmic contacts and localized surface plasmon resonance for enhancing CO2 photoreduction of BiOBr

The fast recombination rate of photogenerated carrier and short electron lifetime are the main factors affecting the CO2 reduction performance of BiOBr (BOB). The utilization of ohmic contacts and the localised surface plasmon resonance (LSPR) effect of metals can effectively solve the above problems. However, one mean alone is not ideal for improving the photocatalytic performance of BOB. Therefore, in this work, we reduced the metal Bi to the surface of BOB in an attempt to form a synergistic effect of ohmic contact and LSPR effect. DFT calculations confirm the ohmic contact between Bi and BOB. Meanwhile, electrochemical tests show that Bi/BOB-2 has a higher photocurrent density (1.1 μA/cm2), suggesting that the ohmic contact achieves ultrafast electron transfer from BOB to Bi under light. While the UV–Vis diffuse reflectance spectroscopy results show resonance absorption peaks from the LSPR effect of Bi, the TRPL results show that Bi/BOB-2 has a longer τave (3.05 ns), implying that longer-lived hot electrons are generated on the Bi surface. The synergistic effect of the two contributes to the efficient CO2 to CO transition on the catalyst surface. As a result, Bi/BOB-2 exhibites a 4.37-fold higher CO generation rate (11.45 μmolg-1 h−1) than that of pure BOB (2.62 μmolg-1 h−1) under light. This study provides a new blueprint for the design of BiOBr-based materials for efficient photocatalytic reduction of CO2.

Applications of optical control materials based on localized surface plasmon resonance effect in smart windows

Applications of optical control materials based on localized surface plasmon resonance effect in smart windows

Photocatalytic H2O2 production and fuel cell performance based on PDI nanobelts enhanced by surface plasmon resonance of gold nanoparticles

The photocatalytic hydrogen peroxide (H2O2) fuel cell represents an innovative self-powered apparatus amalgamating the production and conversion of H2O2 to supply electricity. Using efficient photocatalyst as photoanode to realize two-electron water oxidation to produce H2O2 is considered as a key factor to improve the performance of fuel cell. In this study, perylene imide nanobelts decorated with gold nanoparticles (Au/PDI) were synthesized and subsequently employed as the photoanode to construct a photocatalytic H2O2 fuel cell. This cell can produce H2O2 under irradiation and store it, subsequently utilizing the stored H2O2 to generate electricity in the absence of light. The maximum power density of Au/PDI-based cell could reach 1.07 mW·cm−2 under AM 1.5 G solar light, which has around 1.7 times enhancement compared to PDI-based cell. Meanwhile, a specific capacitance of 5661 mF·cm−2 was obtained after 3 h irradiation. After operating the cell for 12 h, the specific capacitance remained at 50.2 % of its initial value. It is indicated that PDI-based photocatalysts hold considerable promise in water oxidation for H2O2 production. The incorporation of noble nanometals has shown effective enhancement in photocatalytic H2O2 production through the localized surface plasmon resonance (LSPR) effects, thereby enriching the photoanode materials designed for H2O2 fuel cell application.

Enhanced photocatalytic hydrogen evolution performance of Pd/g-C3N4 with carbon vacancies

Exploration of highly active, stable and environmentally friendly photocatalytic materials is key to address the problem for hydrogen production by photocatalytic water splitting. Among all the photocatalysts, graphitic carbon nitride (g-C3N4) has gained attention for its stable graphite-like electronic structure, appropriate band gap (∼2.7 eV), and high stability. However, the limited visible light absorption capacity and fast recombination of electron-hole pairs severely limit the photocatalytic performance of g-C3N4. In this study, Pd/g-C3N4 Schottky heterojunctions with carbon vacancies were prepared by an impregnation method. The surface plasmon resonance (SPR) effect of Pd0 nanoparticles and the incorporation of carbon vacancies synergistically reduce the band gap of g-C3N4, expanding its light response absorption capacity and increasing surface active sites, as a result of these modifications, the separation of electron-hole pairs is effectively improved, and photocatalytic water splitting for hydrogen production is greatly enhanced. Photocatalytic performance of Pd/g-C3N4 photocatalysts demonstrate outstanding hydrogen evolution efficiency under solar light irradiation. A convincing mechanism for the enhanced photocatalytic performance of the Pd/g-C3N4 Schottky heterojunctions was suggested. This investigation emphasizes a straightforward and efficient approach for fabricating of based g-C3N4 composite materials with exceptional photocatalytic efficiency.

Efficient photocatalytic reforming of cellulose for H2 production enabled by oxygen-vacancy rich SrMoO4/palygorskite nanocomposite

Photocatalytic reforming of biomass into hydrogen along with the simultaneous production of high-value chemicals, plays a significant role in advancing a sustainable economy. A major challenge in this process is the effective utilization of photogenerated holes while simultaneously preventing the rapid recombination of photoinduced carriers, which is crucial for optimizing solar-to-hydrogen conversion efficiency. In this study, an exquisite oxygen-rich vacancy (OV) plasmonic SrMoO4/phosphor acidized palygorskite (H-Pal) nanocomposite was prepared for efficient photocatalytic H2 evolution while producing high value-added lactic acid (LA) simultaneously. Results showed that the integration of local surface plasmon resonance (LSPR) effect and OV enhanced the photothermal catalytic conversion of cellulose reaching as high as 87%. Notably, the selectivity of LA reached as high as 31% while the H2-evolution efficiency reached 906 μmol•g-1•h-1. The local thermal effect improved the conversion efficiency of cellulose, and the OV in SrMoO4 introduced instantaneous Lewis acid sites during light irradiation, which improved the selectivity for LA. Moreover, the formation of an S-scheme SrMoO4-OV/H-Pal heterostructure effectively inhibited the recombination of photogenerated electron-hole pairs and maintained a high redox potential. This work demonstrates a promising strategy for efficient photocatalytic H2-evolution, coupled with production of high-valuable chemicals from biomass resources by taking advantage of clay materials.

High-Speed and High-Responsivity Blue Light Photodetector with an InGaN NR/PEDOT:PSS Heterojunction Decorated with Ag NWs.

InGaN nanorods possessing larger and wavelength selective absorption by regulating In component based visible light photodetectors (PDs) as one of the key components in the field of visible light communication have received widespread attention. Currently, the weak photoelectric conversion efficiency and slow photoresponse speed of InGaN nanorod (NR) based PDs due to high surface states of InGaN NRs impede the actualization of high-responsivity and high-speed blue light PDs. Here, we have demonstrated high-performance InGaN NR/PEDOT:PSS@Ag nanowire (NW) heterojunction blue light photodetectors utilizing surface passivation and a localized surface plasmon resonance effect. The dark current is significantly reduced by passivating the InGaN NR surface states using PEDOT:PSS. The photoelectric conversion efficiency is significantly increased by increasing light absorption due to the electromagnetic field oscillation of Ag NWs. The responsivity, external quantum efficiency, detectivity, and fall/off time of the InGaN NR/PEDOT:PSS@Ag NW PDs are up to 2.9 A/W, 856%, 6.64 × 1010 Jones, and 439/725 μs, respectively, under 1 V bias and 420 nm illumination. The proposed device design presents a novel approach toward the development of low-cost, high-responsivity, high-speed blue light photodetectors for applications involving visible light communication.

Silver Nanoparticle-Embedded Carbon Nitride: Antifungal Activity on Candida albicans and Toxicity toward Animal Cells.

The development of engineered nanomaterials has been considered a promising strategy to control oral infections. In this study, silver-embedded carbon nitrides (Ag@g-CN) were synthesized and tested against Candida albicans, investigating their antifungal action and biocompatibility in animal cells. Ag@g-CN was synthesized by a simple one-pot thermal polymerization technique and characterized by various analytical techniques. X-ray diffraction (XRD) analysis revealed slight alterations in the crystal structure of g-CN upon the incorporation of Ag. Fourier transform infrared (FT-IR) spectroscopy confirmed the presence of Ag-N bonds, indicating successful silver incorporation and potential interactions with g-CN's amino groups. UV-vis spectroscopy demonstrated a red shift in the absorption edge of Ag@g-CN compared with g-CN, attributed to the surface plasmon resonance effect of silver nanoparticles. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) confirmed the 2D layered sheet like morphology of both materials. The Ag 3d peaks found in X-ray photoelectron spectroscopy (XPS) confirmed the presence of metallic Ag0 nanoparticles in Ag@g-CN. The Ag@g-CN materials exhibited high antifungal activity against reference and oral clinical strains of C. albicans, with minimal inhibitory concentration (MIC) ranges between 16-256 μg/mL. The mechanism of Ag@g-CN on C. albicans was attributed to the disruption of the membrane integrity and disturbance of the biofilm. In addition, the Ag@g-CN material showed good biocompatibility in the fibroblastic cell line and in Galleria mellonella, with no apparent cytotoxicity observed at a concentration up to 1000 μg/mL. These findings demonstrate the potential of the Ag@g-CN material as an effective and safe antifungal agent for the treatment of oral fungal infections.

Multiple synergistic antibacterial melamine-impregnated paper based on nano Ag-doped ZIF-8

Melamine-impregnated paper, a decorative material in furniture and interior design, could potentially impede the spread of indoor bacteria if it possesses antibacterial properties. Here, nano Ag-doped ZIF-8 (Ag@ZIF-8) was synthesized using ion exchange and in-situ chemical reduction strategies, followed by incorporating it into melamine-impregnated paper. The ion exchange mechanism of Zn2+ and Ag+ during ion exchange reactions was investigated. The structure of Ag@ZIF-8 was well-defined, with Ag nanoparticles evenly distributed on the surface of ZIF-8. Ag@ZIF-8 showed good thermal stability at 400 °C, meeting the requirements for the hot-pressing process of the melamine-impregnated paper. Ag@ZIF-8 exhibited enhanced ROS generation under visible light compare to ZIF-8, which was attributed to its reinforced light absorption and charge carrier separation facilitated by the localized surface plasmon resonance (LSPR) effect. The antibacterial activity of Ag@ZIF-8 was better than ZIF-8, owing to the multiple-synergistic antibacterial mechanisms of the ion release and ROS generation. Specifically, the 10-Ag@ZIF-8 exhibited MIC of 128 μg/mL and 64 μg/mL against E. coli and S. aureus, respectively. The signal intensity of •O2 − induced by 10-Ag@ZIF-8 was 4.38 times higher than that of ZIF-8. As the addition of Ag@ZIF-8 increased, the antibacterial performance of melamine-impregnated paper improved. Considering the antibacterial property and economy of melamine-impregnated paper, 0.20 wt% was the optimal amount for 10-Ag@ZIF-8 decorated blockboard. This study proposes a novel approach for synthesizing MOF-based melamine-impregnated paper with antibacterial properties, aiming to reduce bacterial spread, minimize disease risks, and contribute to lowering overall healthcare costs.

Tightly and abundantly contacted Z-scheme heterojunction of Bi-modified TiO2/BiOCl: In-situ construction and boosting visible-light-driven purification of liquor brewing wastewater

The lower specific surface area and limited surface contact between BiOCl and TiO2 in composite fabricated by hybridization of TiO2 with BiOCl extremely hinder its catalytic performance. In this work, the area of interface contact between BiOCl and TiO2 was increased through the mediation of SiO2, and a Bi-modified ternary 0D/2D/2D TiO2/BiOCl Z-scheme heterojunction photocatalyst with large specific surface area (= 237.83 m2g−1) and surface plasmon resonance (SPR) effect was constructed in situ by ingeniously utilizing the reduction of carbon species generated during the calcination process. The results show that the COD removal rate of Bi/TBOC-10% for real liquor brewing wastewater (LBW) reaches 90.5% after 10 hours of visible light irradiation, which is 2.6 times and 2.1 times that of TiO2 and Degussa P25, respectively. The COD removal rate of the composite was reduced only by 8.9% after five cycles of performance test (50 h). Photoluminescence spectroscopy (PL), Transient Photocurrent Response (TPR), Electrochemical Impedance Spectroscopy (EIS) and BET characterization suggest that its excellent photocatalytic activity should be attributed to the Z-scheme heterojunction that broadens the light absorption range while retains strong oxidation-reduction active sites, the SPR effect that facilitates the separation and migration of photogenerated carriers, and high specific surface area of the composite that provides more active sites for the photodegradation reaction.

Near-Infrared Luminescent Materials Incorporating Rare Earth/Transition Metal Ions: From Materials to Applications.

The spotlight has shifted to near-infrared (NIR) luminescent materials emitting beyond 1000 nm, with growing interest due to their unique characteristics. The ability of NIR-II emission (1000-1700 nm) to penetrate deeply and transmit independently positions these NIR luminescent materials for applications in optical-communication devices, bioimaging, and photodetectors. The combination of rare earth metals/transition metals with a variety of matrix materials provides a new platform for creating new chemical and physical properties for materials science and device applications. In this review, the recent advancements in NIR emission activated by rare earth and transition metal ions are summarized and their role in applications spanning bioimaging, sensing, and optoelectronics is illustrated. It started with various synthesis techniques and explored how rare earths/transition metals can be skillfully incorporated into various matrixes, thereby endowing them with unique characteristics. The discussion to strategies of enhancing excitation absorption and emission efficiency, spotlighting innovations like dye sensitization and surface plasmon resonance effects is then extended. Subsequently, a significant focus is placed on functionalization strategies and their applications. Finally, a comprehensive analysis of the challenges and proposed strategies for rare earth/transition metal ion-doped near-infrared luminescent materials, summarizing the insights of each section is provided.

Fluorescence Enhancement of CdS:Ag Quantum Dots Co-Assembled with Au Nanoparticles in a Hollow Nanosphere Form.

Colloidal quantum dots (QDs) have exceptional fluorescence properties. Overcoming aggregation-induced quenching and enhancing the fluorescence of colloidal QDs have remained a challenging issue in this field. In this study, composite hollow nanospheres composed of Au nanoparticles (NPs) and CdS:Ag-doped QDs were successfully constructed through controlled microemulsion-based cooperative assembly. This method harnessed the localized surface plasmon resonance (LSPR) effect of Au NPs nearby doped QDs, resulting in enhanced doped QD fluorescence and the observation of the Purcell effect. The composite hollow nanospheres show a fluorescence enhancement compared to that of the pure CdS:Ag QDs. The enhanced fluorescence was demonstrated to come from the synergetic enhancement of the absorption and emission transition of the doped QDs. This approach provides a feasible technological pathway to address the challenge of improving the fluorescence performance of the doped QDs.

Double-Enhanced Photothermal Lateral Flow Biosensor Based on Dual Gold Nanoparticle Conjugates.

Bacterial toxins emerge as the primary triggers of foodborne illnesses, posing a significant threat to human health. To ensure food safety, it is imperative to implement point-of-care testing methods. Lateral flow biosensors (LFBs) based on gold nanoparticles (GNPs) have been commonly used for rapid detection, but their applicationis limited by low sensitivity. Based on the localized surface plasmon resonance and photothermal effect of dual gold nanoparticle conjugates (DGNPs), we developed a smartphone-integrated photothermal LFB (PLFB) with double-enhanced colorimetric and photothermal sensitivity. Through numerical simulations, we verified that DGNPs have significantly enhanced photothermal performance compared to single 15 nm GNPs (SGNPs), and applied DGNPs in PLFB for the detection of staphylococcus enterotoxin A (SEA). The colorimetric and photothermal limits of detection of DGNPs-based PLFB for SEA were 0.091 and 0.0038 ng mL-1, respectively. Compared with the colorimetric detection of the SGNPs-based LFB, the colorimetric detection sensitivity of the DGNPs-based PLFB was increased by 10.7 times, and the photothermal detection sensitivity was further improved by 255.3 times. Moreover, the PLFB exhibits robust reproducibility and exceptional specificity and is applicable for detecting SEA in milk samples. This smartphone-integrated PLFB based on DGNPs allows users to detect toxins simply, conveniently, and quickly and has huge application potential in the field of food safety.