Search Results (472)

The development of thin-film organic solar cells (TFOSCs) is pivotal for advancing sustainable energy technologies because of their potential for low-cost, lightweight, and flexible photovoltaic applications. In this study, silver-doped copper sulfide (CuS/Ag) metal nanoparticles (MNPs) were successfully synthesized via a wet chemical method. These CuS/Ag MNPs were incorporated at varying concentrations into a poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) blend, serving as the active layer to enhance the photovoltaic performance of the TFOSCs. The fabricated TFOSC devices were systematically evaluated based on the optical, electrical, and morphological characteristics of the active layer. By varying the concentration of CuS/Ag MNPs, the influence of nanoparticle doping on photocurrent generation was investigated. The device incorporating 1% CuS/Ag MNPs exhibited the highest power conversion efficiency (PCE) of 5.28%, significantly outperforming the pristine reference device, which achieved a PCE of 2.53%. This enhancement is attributed to the localized surface plasmon resonance (LSPR), which augments charge transport and increases optical absorption. The CuS/Ag MNPs were characterized using ultraviolet–visible (UV-Vis) absorption spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive dispersion (EDX) analysis. These findings underscore the potential of CuS/Ag MNPs in revolutionizing TFOSCs, paving the way for more efficient and sustainable solar energy solutions. Full article

A novel, eco-friendly perovskite solar cell design is investigated using numerical simulations based on the finite-difference time-domain (FDTD) method. The proposed structure incorporates a two-dimensional (2D) photonic crystal (PhC) architecture featuring a titanium dioxide (TiO₂) cylindrical electron extraction layer. To reduce fabrication complexity and overall production costs, a hole-transport-layer-free (HTL-free) configuration is employed. Simulation results reveal a significant enhancement in photovoltaic performance compared to conventional planar structures, achieving an ultimate efficiency of 42.3%, compared to 36.6% for the traditional design—an improvement of over 16%. Electromagnetic field distributions are analyzed to elucidate the physical mechanisms behind the enhanced absorption. The improved optical performance is attributed to strong coupling between photonic modes and surface plasmon polaritons (SPPs), which enhances light–matter interaction. Furthermore, the device exhibits polarization-insensitive and angle-independent absorption characteristics, maintaining high performance for both transverse magnetic (TM) and transverse electric (TE) polarizations at incidence angles up to 60°. These findings highlight a promising pathway toward the development of cost-effective, lead-free perovskite solar cells with high efficiency and simplified fabrication processes. Full article

Silver thin films are widely utilized in plasmonic, electronic, and catalytic devices due to their excellent conductivity, optical properties, and surface activity. However, the nanostructure and performance of Ag films are highly dependent on deposition parameters, particularly during radio-frequency magnetron sputtering (RF-MS). In this study, we systematically investigate the effects of RF power, sputtering time, and substrate type on the growth behavior, crystallinity, and electrical conductivity of Ag films. Optical emission spectroscopy (OES) and Langmuir probe diagnostics were employed to analyze the plasma environment, revealing the evolution of electron temperature and plasma density with varying RF powers. Structural characterizations using XRD, SEM, and AFM demonstrate that higher RF power results in reduced grain size, increased film density, and improved crystallinity, while deposition time influences film thickness and grain coalescence. Substrate material also plays a key role, with Cu substrates promoting better crystallinity due to improved lattice matching. Electrical measurements show that denser films with larger grains exhibit lower sheet resistance. These findings provide a comprehensive understanding of the plasma–film interplay and offer strategic insights for optimizing silver nanofilms in high-performance optoelectronic and catalytic systems. Full article

Graphene, a two-dimensional carbon material with a hexagonal lattice structure, possesses remarkable properties. Exceptional electrical conductivity, mechanical strength, and high surface area that make it a powerful platform for biosensing applications. Its sp²-hybridised network facilitates efficient electron mobility and enables diverse surface functionalisation through bio-interfacing. This review highlights the core detection mechanisms in graphene-based biosensors. Optical sensing techniques, such as surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS), benefit significantly from graphene’s strong light–matter interaction, which enhances signal sensitivity. Although graphene itself lacks intrinsic piezoelectricity, its integration with piezoelectric substrates can augment the performance of piezoelectric biosensors. In electrochemical sensing, graphene-based electrodes support rapid electron transfer, enabling fast response times across a range of techniques, including impedance spectroscopy, amperometry, and voltammetry. Graphene field-effect transistors (GFETs), which leverage graphene’s high carrier mobility, offer real-time, label-free, and highly sensitive detection of biomolecules. In addition, the review also explores multiplexed detection strategies vital for point-of-care diagnostics. Graphene’s nanoscale dimensions and tunable surface chemistry facilitate both array-based configurations and the simultaneous detection of multiple biomarkers. This adaptability makes graphene an ideal material for compact, scalable, and accurate biosensor platforms. Continued advancements in graphene biofunctionalisation, sensing modalities, and integrated multiplexing are driving the development of next-generation biosensors with superior sensitivity, selectivity, and diagnostic reliability. Full article

As a vital transition metal species, cobalt ions (Co²⁺) play a critical role in industrial and medical fields. However, uncontrolled release into ecosystems via industrial effluents presents significant environmental risks. To address this, a prism-coupled surface plasmon resonance (SPR) sensor chip was developed which enables simultaneous high sensitivity, wide detection range, and rapid detection of Co²⁺ under ultra-low detection limit conditions. By depositing a 50 nm Au film and AuNPs on a glass substrate, and integrating carboxyl-functionalized carbon quantum dots (CQDs), the chip achieved the detection range of 10⁻²⁰ mol/L to 10⁻⁴ mol/L, and the response time was reduced from 21 min to 11 min under optimal electric field conditions (1.2 V, 0.15 mol/L electrolyte concentration). The sensor exhibits high selectivity, repeatability, and stability. It can be integrated with optofluidic technology to enable high-throughput microfluidic analysis, thereby facilitating further advancements in related research. Full article

The photonic spin Hall effect (PSHE) has emerged as a powerful metrological approach for precision measurements. Dynamic manipulation of PSHE through external stimuli could substantially expand its applications. In this work, we present a simple and active modulation scheme for PSHE in a surface plasmon resonance (SPR) structure by exploiting electric-field-tunable refractive indices of electro-optic materials. By applying an electric field, the enhancement of PSHE spin shifts is observed, and the dual-field control can further amplify these spin shifts through synergistic effects in this SPR structure. Notably, various operation modes of external electric field enable the real-time switching between two high-performance sensing functionalities (refractive index detection and angle measurement). Therefore, our designed PSHE sensor based on SPR structure with a simple structure of only three layers not only makes up for the complex structure in multi-functional sensors, but more importantly, this platform establishes a new paradigm for dynamic PSHE manipulation while paving the way for advanced multi-functional optical sensing technology. Full article

The integration of organoids with biosensors serves as a miniaturized model of human physiology and diseases, significantly transforming the research frameworks surrounding drug development, toxicity testing, and personalized medicine. This review aims to provide a comprehensive framework for researchers to identify suitable technical approaches and to promote the advancement of organoid sensing towards enhanced biomimicry and intelligence. To this end, several primary methods for technology integration are systematically outlined and compared, which include microfluidic integrated systems, microelectrode array (MEA)-based electrophysiological recording systems, optical sensing systems, mechanical force sensing technologies, field-effect transistor (FET)-based sensing techniques, biohybrid systems based on synthetic biology tools, and label-free technologies, including impedance, surface plasmon resonance (SPR), and mass spectrometry imaging. Through multimodal collaboration such as the combination of MEA for recording electrical signals from cardiac organoids with micropillar arrays for monitoring contractile force, these technologies can overcome the limitations inherent in singular sensing modalities and enable a comprehensive analysis of the dynamic responses of organoids. Furthermore, this review discusses strategies for integrating strategies of multimodal sensing approaches (e.g., the combination of microfluidics with MEA and optical methods) and highlights future challenges related to sensor implantation in vascularized organoids, signal stability during long-term culture, and the standardization of clinical translation. Full article

The design of photocatalysts capable of generating localized surface plasmon resonance (LSPR) effects represents a promising strategy for enhancing photocatalytic activity. However, the mechanistic role of plasmonic nanoparticles-induced interfacial electric fields in driving photocatalytic processes remains poorly understood. To produce a Schottky junction, varying amounts of Au nanoparticles widely utilized to broaden the light absorption were loaded onto ultrathin carbon nitride sheets (Au/UCN). The Au/UCN-20 Schottky junction exhibits exceptional photocatalytic activity, achieving a hydrogen evolution rate (14.2 mmol·g⁻¹ over a 4 h period) while maintaining robust stability through five consecutive photocatalytic cycles. The LSPR activity of Au nanoparticles are responsible for the broadened light absorption spectrum of Au/UCN nanocomposites. The interfacial electric field generated at the Au /UCN heterojunction is proposed to enhance charge-transfer efficiency through Schottky barrier penetration of photocarriers, mediated by electric field-driven carrier migration, according to surface potential and finite-difference time-domain (FDTD). These findings uncover a previously obscured photocatalytic mechanism driven by LSPR-induced interfacial electric fields, pioneering a quantum-dot-directed strategy to precisely engineer charge dynamics in advanced photocatalysts via targeted manipulation of nanoscale electric field effects. Full article

This numerical study introduces a surface plasmon resonance (SPR)-based biosensor utilizing a kagome lattice-inspired hollow core photonic crystal fiber (PCF) for the highly sensitive detection of various blood biomarkers and analytical components. The sensor is designed to detect key blood biomarkers such as water, glucose, plasma, and hemoglobin (Hb), as well as analytical targets including krypton, sylgard, ethanol, polyacrylamide (PA), and bovine serum albumin (BSA), by monitoring shifts in the resonance wavelength (RW). A dual-polarization approach is employed by analyzing both transverse magnetic (TM) and transverse electric (TE) modes. The proposed sensor demonstrates exceptional performance, achieving maximum wavelength sensitivities (Sw) of 18,900 nm RIU⁻¹ for TM pol. and 16,800 nm RIU⁻¹ for TE pol. Corresponding peak amplitude sensitivities (S_A) of 71,224 RIU⁻¹ for TM pol. and 58,112 RIU⁻¹ for TE pol. were also observed. The peak sensor resolution (S_R) for both modes is on the order of 10⁻⁶ RIU, underscoring its high precision. Owing to its enhanced sensitivity, compact design, and robust dual-polarization capability, the proposed biosensor holds strong promise for point-of-care diagnostics and real-time blood component analysis. Full article

In this article, femtosecond laser scanning was used to create heterojunctions between silver nanowire (Ag NW) and graphene oxide (GO), resulting in a mechanical and electrical interconnection. Surface plasmon resonances (SPRs) were generated on the nanowire surface by using femtosecond laser irradiation, producing a periodically excited electric field along the Ag NWs. This electric field then interfered with the femtosecond laser field, creating strong localized heating effects, which melted the Ag NW and GO, leading to mechanical bonding between the two. The formation of these heterostructures was attributed to the transfer of plasmon energy from the Ag NW to the adjacent GO surface. Since the connection efficiency of the nanowires is closely related to the specific location and the polarization direction of the laser, FDTD simulations were conducted to model the electric field distribution on the surface of Ag NW and GO structures under different laser polarization directions, varying the lengths and diameters of the nanowires. Finally, the resistance changes of the printed Ag NW paths on the GO thin film after femtosecond laser irradiation were investigated. It was found that laser bonding could reduce the resistance of the Ag NW-GO heterostructures by two orders of magnitude, further confirming the formation of the junctions. Full article

This paper investigates a graphene-on-insulator power divider designed for terahertz applications based on spoof surface plasmon polaritons. We optimize structural parameters to maximize signal transmission from input to output ports while achieving a uniform and symmetrical electric field distribution at the output cross-section. Our findings indicate that utilizing three graphene layers significantly enhances power distribution and symmetry at output ports. We demonstrate electrical control over waveguide transmission properties by modulating the graphene chemical potential from 0 to 0.5 eV. The proposed device holds promise for applications in plasmonic circuits and on-chip interconnects operating within the terahertz frequency range. Full article

Conventional all-optical modulators based on surface plasmon polaritons (SPPs) primarily utilize the nonlinear effect of a given material for modulation. Their performance is heavily dependent on the optical properties of the dielectric materials used and requires high pumping power. However, manipulating SPPs by controlling electron concentrations offers a material-independent approach suitable for all-optical modulators. In this paper, we propose a hybrid gold–ITO–silver block structure integrated within a Mach–Zehnder interferometer configuration to address this problem. The gold–ITO interface effectively localizes propagating SPPs. The pump light excites localized surface plasmons (LSPs) in the silver block, generating surface electric fields that modulate the electron concentration in the adjacent ITO layer. The extinction ratio is 50.8 dB when the electron concentration changes by 3.3 × 10²⁰ cm⁻³, indicating that this structure is an all-optical modulator with a high extinction ratio. This approach shows significant promise for reducing pump power and enhancing the performance of all-optical modulators. Full article

Gold nanoparticles (AuNPs) anchored on graphene oxide (GO) have had a significant interest for their unique optical, electrical, and catalytic properties. This study presents an eco-friendly and sustainable synthesis of AuNPs on GO sheets using L-ascorbic acid (L-aa) as a green reducing agent and polyvinylpyrrolidone (PVP) as a stabilizer. The effect of reductant concentration on nanoparticle morphology was systematically investigated using UV–Visible spectroscopy and transmission electron microscopy (TEM). Results indicate the formation of AuNPs anchored on GO sheets and that an increase in the L-aa amount leads to both an increase in nanoparticle size and a morphological transition from spherical to irregular structures. The simultaneous nucleation and growth processes result in the formation of multiple families of nanostructures, as confirmed by TEM analysis, which reveals two distinct size distributions. At higher L-aa concentrations, the nanoparticles shape evolves into irregular morphologies due to selective growth along a preferential facet. This approach not only enables precise control over AuNP size and shape but also aligns with green chemistry principles, making it a promising route for applications in plasmonics, sensors, and photothermal therapy. Full article

This paper proposes a high-sensitivity U-shaped optical fiber sensor based on indium tin oxide (ITO) for surface plasmon resonance (SPR) sensing. Finite element simulations reveal that introducing ITO enhances the surface electric field strength by 1.15× compared to conventional designs, directly boosting sensitivity. The U-shaped structure optimizes evanescent wave–metal film interaction, further improving performance. In an external refractive index (RI) range of 1.334–1.374 RIU, the sensor achieves a sensitivity of 4333 nm/RIU (1.85× higher than traditional fiber sensors) and a figure of merit (FOM) of 21.7 RIU⁻¹ (1.68× improvement). Repeatability tests show a low relative standard deviation (RSD) of 0.4236% for RI measurements, with a maximum error of 0.00018 RIU, confirming excellent stability. The ITO coating’s strong adhesion ensures long-term reliability. With its simple structure, ease of fabrication, and superior sensitivity/FOM, this SPR sensor is well-suited for high-precision biochemical detection in intelligent sensing systems. Full article

Surface plasmon resonance (SPR) detection technology is playing an important role in various fields such as food safety and environmental monitoring due to its excellent stability and reliability. However, there is also a growing demand for higher sensitivity in SPR sensors. Therefore, this work developed an SPR sensor based on the synergistic effect of electric-field enhancement and adsorption enhancement by using amino acid-derived carbon dots (CDs). The results showed that the incorporation of amino acid CDs can generate a maximum electric-field enhancement of up to 6.44 × 10⁵ V/m in the near-field region, which is 312% of that achieved by a bare gold film. And the adsorption kinetics results indicate that the active groups on the surface of amino acid CDs exhibit a notable adsorption enhancement effect for the target molecule (NaCl), with an adsorption capacity 335% higher than that of the bare gold film. This designed SPR sensor demonstrates a detection sensitivity of 167.28 a.u./RIU for NaCl solution, representing a 247.8% improvement compared to an SPR sensor without amino acid CDs under the same conditions. This SPR sensor shows promising potential for applications in biomedical and environmental detection fields. Full article