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A triple‐junction tandem organic solar cell (OSC) having polymer active materials, P3HT:PC70BM, Si‐PCPDTBT:PC70BM, and PMDPP3T:PC70BM is presented. These active layer materials cover a 300 nm to 1000 nm broad solar spectrum and have minimally overlapping narrow absorption bands. The performance of the triple‐junction tandem OSC was improved by introducing plasmonic nanospheres (NSs) over the top electrode of the OSC. The OSCs were modeled in finite‐difference time‐domain (FDTD) to optimize the performance of the NSs. Nanospheres of three plasmonic materials—gold (Au), silver (Ag), and aluminum (Al) were individually simulated over the top electrode of the OSCs. The NSs affect absorption in the active layer materials, around their respective plasmonic resonance peaks. The low‐cost Al NSs enhance light trapping in the top and middle subcells, leading to a 14% improvement in overall short circuit current density (JSC) of the triple‐junction tandem OSC in comparison with that of the reference OSC without any NSs. It is also observed that while the enhancement of the overall JSC of the triple‐junction tandem OSC due to the Al NSs is greater than that due to the Ag NSs, the presence of Au NSs leads to a decrease in the overall JSC in comparison with that of the reference OSC.

Here, we introduce a microchip for differential measurements of aqueous samples in twin calorimetric arms with a sub-nL enclosed space. Each arm features a fluidic microchannel located in close proximity to a thin-film resistance thermometer and heater patterned on a low-stress SiN membrane held over a Si cavity with suspension beams. The chip exhibits a rapid response with a thermal time constant of less than 10 ms in atmosphere and a residual thermal conductance below $6{\mu }\text{W}{\cdot }\text{K}^{-1 }$ , one of the lowest reported and accounts for the excellent sensitivity registered in vacuum up to 11 $\text{V}{\cdot }\text{W}^{-1 }$ . These values are in good agreement with those ones predicted by modeling using finite element method, lumped-capacitance analysis, and calorimeter electrothermal circuit simulation together with the measurement system. Long suspension beams in each arm ensure uniform temperature maintained across its membrane as revealed by the fluorescence-based melting curve analysis. We share the specific heat capacity values of water, glycerin, and mineral oil accurately measured by the chip. Lastly, we demonstrate the chip calorimeter utility on the measurement of the photothermal transduction efficiency of plasmonic nanoparticles, which makes our study further unique in expanding the applications of chip calorimeters. [2021-0044]

Coupled plasmonic systems are of great interest and have many applications such as information processing and sensing. By choosing proper geometric configurations of coupled plasmonic systems, one can obtain various optical properties. However, some interesting and important effects could not be described by earlier methods. We develop an improved method for coupled plasmonic nanoparticle systems that maps geometric configurations to optical properties more accurately. With the improved method, we realize a low-loss cavity of metallic nanoparticles through a proper geometric configuration, and we find a limit to the loss in the metallic nano-cavity. We also use this method to realize an exceptional point and exceptional nexus in a hybrid plasmonic system. Finally, we predict asymmetric coupling, which leads to chirality and directional energy transfer.

Water desalination through steam generation using solar energy not only is a low cost and facile technology but also uses a free source of energy. This technology is performed through two direct and indirect methods. This work focuses on the direct one where the materials, mechanisms, and structures used for desalinating water through the production of steam by solar energy are reviewed. Since the light absorber is the heart of the system, all absorber types with a variety of structures including graphene, graphite, carbon, carbon nanotube (CNT), carbonized wood, plants, polymers, and plasmonic nanoparticles are studied. It is shown that how the material, structure, and design of the absorbers have been tuned to overcome the challenges regarding the performance and cost effectiveness of these systems, leading to propos the perspective on future development of this structures.

Weak reactions are usually overlooked due to weak detectable features and susceptibility to interference from noise signals. Strategies for detecting weak reactions are essential for exploring reaction mechanisms and exploiting potential applications. Machine learning has recently been successfully used to identify patterns and trends in the data. Here, it is demonstrated that machine learning-based techniques can offer accurate local surface plasmon resonance (LSPR) scatterometry by improving the precision of the plasmonic scattering imaging in weak chemical reactions. Dark-field microscopy (DFM) imaging technique is the most effective method for high-sensitivity plasmonic nanoparticles LSPR scatterometry. Unfortunately, deviations caused by the instrument and operating errors are inevitable, and it is difficult to effectively detect the presence of weak reactions. Thus, introducing a machine learning calibration model to automatically calibrate the scattering signal of the nanoprobe in the reaction process can greatly improve the confidence of LSPR scatterometry under DFM imaging and allow DFM imaging to effectively monitor unobvious or weak reactions. By this approach, the weak oxidation of silver nanoparticles (AgNPs) in water by dissolved oxygen was successfully monitored. Moreover, a trivial reaction between AgNPs and mercury ions was detected in a dilute mercury solution with a concentration greater than 1.0 × 10-10 mol/L. These results suggest the great potential of the combination of LSPR scatterometry and machine learning as a method for imaging analysis and intelligent sensing.

The optical and dielectric properties of plasmonic of Fe2O3/Au and Fe3O4/Au core/shell nanoparticles were studied using Finite Element computational approach. The optical response of these nanostructures was investigated through the computation of the real and the imaginary parts of the effective dielectric permittivity and the absorption cross-section in the visible-near infrared spectral range. Our findings are as follows. Firstly, we have compared our obtained numerical results with those predicted by Maxwell–Garnett effective medium theory. Secondly, the obtained results reveal that the localized surface plasmons resonance (LSPR) peak shifts to near infrared for a Fe2O3/Au-nanoparticle are similar to that of a Fe3O4/Au-nanoparticle having the same geometric parameters. Thirdly, the optical characteristics of the plasmonic nanoparticles were also studied. Finally, we hope that the developed numerical method can be extended to investigate the electromagnetic coupling within or between particles and its effect on the plasmonic behaviors. This makes the core/shell composite nanoparticles extremely interesting for magnetic, optical and biomedical applications.

Numerous laboratories have observed random lasing from optically pumped solutions of plasmonic nanoparticles (NPs) suspended with organic dye molecules. The underlying mechanism is typically attributed to the formation of closed-loop optical cavities enabled by the large local field and scattering enhancements in the vicinity of plasmonic NPs. In this manuscript, we propose an alternative mechanism that does not directly require the plasmon resonance. We used high-speed confocal microspectroscopy to observe the photophysical dynamics of NPs in solution. Laser pulses induce the formation of microbubbles that surround and encapsulate the NPs, then sharp peaks

In the current investigation, the plasmonic nano-cubes were used to improve the absorption of an organic-inorganic hybrid crystalline-based CH3NH3PbX3 perovskite solar cell. One of the critical challenges of plasmonic nanoparticles is their parasitic absorption that would compensate or even surpass the effect of plasmonic nanoparticles. So, the effects of parasitic absorption inside the nanoparticles were evaluated. By incorporating the plasmonic effect of nano-cubes, the parasitic absorption of Al and Ag nano-cubes and the absorption spectrum of the perovskite absorber were calculated. The parasitic absorption of nano-cubes was subtracted, and net absorption was obtained before calculating the photocurrents. Optimization is done to find the best nano-cubes edges and the period of the unit cell. Using Al and Ag nano-cubes increases the photocurrent increase to 23 mA/cm2, and 22 mA/cm2 in a cell with a thickness of 200 nm, respectively. The photocurrent of the reference cell is 17.70 mA/cm2. So, the enhancement factors of 29%, and 24.3% were obtained for them in comparison to the reference cell, respectively. Moreover, the boosted photon absorption was confirmed through the electrical field distribution and the profiles of generation rate. The results can be used to establish some guidelines for a realistic understanding of plasmonic resonance-based photovoltaic devices.

Perovskite solar cells (PSCs) based on lead halide and solution process face issues such as low efficiency and high manufacturing costs. Recently, the emerging field of plasmonics as a branch of photonics has been utilized in electronic, optic and electro-optic devices, which deals with optical phenomena in metallic nanostructures like Au, Ag and Cu. One way to enhance the efficiency is the increase of absorbent layer thickness, while increasing the manufacturing cost. Here, we intend to examine the size, number, and composition of random plasmonic nanoparticles (RPNPs) in the active layer (AL) so that we can increase the power conversion efficiency (PCE) without changing the absorbent layer thickness. The simulation results demonstrate an improve in photocurrent of the device as much as 11.12% (18.24–20.27 mA/cm2) using the near-field plasmon-enhanced properties of RPNPs, while the number and radius of PNPs embedded in the AL are 50 and 10 nm, respectively. With Ag RPNPs, the photocurrent increases up to 16.5% (18.24–21.25 mA/cm2). Utilizing RNPNs is an efficient method for improving PCE in PSCs with thin absorption layer (up to 200 nm). Given the optimal parameters obtained for RPNPs, our study is very useful for the development of PSCs.

Plasmonic effects of various sized Al nanospheres non-embedded on Ta2O5 antireflective–coated single-junction GaAs solar cells are analyzed by finite difference time domain (FDTD) simulations. The impact of optimized plasmonic nanoparticles is further analyzed for embedded Al nanospheres in GaAs and compared with nanoparticles at back contact. It is found that the nanoparticles of radius 30 nm show superior spectral response in comparison with other radii for non-embedded design. Further, non-embedded optimized nanoparticles show better spectral response when embedded in GaAs layer 10 nm below the Ta2O5 antireflection layer, which yields a maximum current density of 28.17 mA/cm2. Moreover, photovoltaic current–voltage characteristics were studied to confirm the performance enhancement induced by Al nanoparticle plasmons. The power conversion efficiency enhancement of 5.4, 11.5, and 2.3% for optimized radius of 30 nm in non-embedded, embedded (at optimized depth of 10 nm), and at rear surface, respectively, were found compared to Ta2O5-coated single-junction GaAs solar cells.

In this paper, the scattering-to-absorption ratio that is a measurable factor and defined as the ratio of the scattering cross section to the absorption cross section in plasmonic core-shell nanoparticles with different shapes is investigated. The effect of various plasmonic materials on the scattering-to-absorption ratio is presented that can tune the plasmon resonance and play a key role in plasmonic solar cell efficiency improvement. In addition to using plasmonic materials as silver and gold, we use poor metals as bismuth because these types of metals are good materials for UV plasmonics. We also use semiconductor copper chloride (CuCl) in our calculations, because this material exhibits a strong exciton resonance, while the interaction between the plasmon resonance in metals and the exciton resonance in CuCl leads to new plexcitonic modes.

Dynamic control of circular polarization in chiral metasurfaces is being used in many photonic applications. However, simple fabrication routes to create chiral materials with considerable and fully tunable chiroptical responses at visible and near-infrared wavelengths are scarce. Here, we describe a scalable bottom-up approach to construct cross-stacked nanoparticle chain arrays that have a circular dichroism of up to 11°. Due to their layered design, the strong superchiral fields of the inter-layer region are accessible to chiral analytes, resulting in a tenfold enhanced sensitivity in a chiral sensing proof-of-concept experiment. In situ restacking and local mechanical compression enables full control over the entire set of circular dichroism characteristics, namely sign, magnitude and spectral position. Strain-induced reconfiguration opens up an intriguing route towards actively controlled pixel arrays using local deformation, which fosters continuous polarization engineering and multi-channel detection. Stacked elastomeric arrays containing plasmonic nanoparticles show efficient chiral responses that can be fully controlled by mechanical compression and stack rotation. These simple layered materials may be useful modulators for photonic applications.

Four-wave mixing at plasmonic tip-sample nanojunctions may be used to visualize plasmonic fields with sub-2 nm spatial resolution under ambient laboratory conditions. We illustrate the latter using a gold-coated atomic force microscopy probe irradiated with a pair of near-infrared femtosecond laser pulses and used to image plasmonic gold nanoplates and silver nanocubes. Through diagnostic polarization-dependent tip-only measurements, we illustrate that the four-wave mixing signal is localized to the tip apex. The apex-bound signal is further enhanced when the tip is located at specific locations near plasmonic nanoparticles. Overall, this work paves the way for visualizing chemical transformations as well as coherent electronic and vibrational dynamics with joint femtosecond temporal and few-nanometer spatial resolution under ambient conditions.

7 pags., 4 figs., Electrogenerated chemiluminescence (ECL) mi- croscopy shows promise as a technique for mapping chemical reactions on single nanoparticles. The technique¿s spatial resolution is limited by the quantum yield of the emission and the diffusive nature of the ECL process. To improve signal intensity, ECL dyes have been coupled with plasmonic nano- particles, which act as nanoantennas. Here, we characterize the optical properties of hexagonal arrays of gold nanodisks and how they impact the enhancement of ECL from the coreaction of tris(2,2¿-bipyridyl)dichlororuthenium(II) hexahydrate and tripro- pylamine. We find that varying the lattice spacing results in a 23- fold enhancement of ECL intensity because of increased dye-array near-field coupling as modeled using finite element method simulations., This work was primarily supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, CPIMS Program under Award #DE-339SC0016534. We also acknowledge funding from the Robert A. Welch Foundation (Grant C-1787 to C.F.L. and Grant C-1664 to S.L.) We would like to thank support from the U.S. National Science Foundation (Grant ECCS-1710697) and Ministerio de Ciencia, Innovación y Universidades of Spain (Grant TEM-FLU PID2019-109502GA-I00), as well as the UNM Center for Advanced Research Computing, for providing the part of the computational resources used in this work. We also thank Grants-in-Aid for Scientific Research (JP 16H06506) from MEXT, and the Photoexcitonix Project of Hokkaido University.

The localized surface plasmon resonance of plasmonic nanoparticles (NPs) can be coupled with a noble metal substrate (S) to induce a localized augmented electric field (E-field) concentrated at the NP-S gap. Herein, we analyzed the fundamental near-field properties of metal NPs on diverse substrates numerically (using the 3D finite-difference time-domain method) and experimentally [using surface-enhanced Raman scattering (SERS)]. We systematically examined the effects of plasmonic NPs on noble metals (Ag and Au), non-noble metals (Al, Ti, Cu, Fe, and Ni), semiconductors (Si and Ge), and dielectrics (TiO2, ZnO, and SiO2) as substrates. For the AgNPs, the Al (11,664 times) and Si (3969 times) substrates produced considerable E-field enhancements, with Al in particular generating a tremendous E-field enhancement comparable in intensity to that induced by a Ag (28,224 times) substrate. Notably, we found that a superior metallic character of the substrate gave rise to easier induction of image charges within the metal substrate, resulting in a greater E-field at the NP-S gap; on the other hand, the larger the permittivity of the nonmetal substrate, the greater the ability of the substrate to store an image charge distribution, resulting in stronger coupling to the charges of localized surface plasmon resonance oscillation on the metal NP. Furthermore, we measured the SERS spectra of rhodamine 6G (a commonly used Raman spectral probe), histamine (a biogenic amine used as a food freshness indicator), creatinine (a kidney health indicator), and tert-butylbenzene [an extreme ultraviolet (EUV) lithography contaminant] on AgNP-immobilized Al and Si substrates to demonstrate the wide range of potential applications. Finally, the NP-S gap hotspots appear to be widely applicable as an ultrasensitive SERS platform (∼single-molecule level), especially when used as a powerful analytical tool for the detection of residual contaminants on versatile substrates.

Surface plasmon coupled emission (SPCE) is a new analytical technique that provides increased and directional radiation based on the near-field interaction between fluorophores and surface plasmons but suffers from the limitation of insufficient sensitivity. The assembly of hollow-porous plasmonic nanoparticles could be the qualified candidate. After the introduction of gold nanocages (AuNCs), fluorescence signal enhancement was realized by factors over 150 and 600 compared with the normal SPCE and free space emission, respectively, with a fluorophore layer thickness of approximately 10 nm; hence, the unique enhancement of SPCE by the AuNCs effectively overcomes the signal quenching induced by resonance energy transfer (in normal SPCE). This enhancement was proven to be triggered by the superior wavelength match, the enhanced electromagnetic field, and new radiation channel and process induced by the AuNC assembly, which provides an opportunity to increase the detection sensitivity and establish an optimal plasmonic enhancement system. The amplified SPCE system was employed for multiwavelength simultaneous enhancement detection through the assembly of mixed hollow nanoparticles (AuNCs and gold nanoshells), which could broaden the application of SPCE in simultaneous sensing and imaging for multianalytes.

Expanding the activity of wide bandgap semiconductors from the UV into the visible range has become a central goal for their application in green solar photocatalysis. The hybrid plasmonic/semiconductor system, based on silver nanoparticles (Ag NPs) embedded in a film of CeO2, is an example of a functional material developed with this aim. In this work, we take advantage of the chemical sensitivity of free electron laser (FEL) time-resolved soft X-ray absorption spectroscopy (TRXAS) to investigate the electron transfer process from the Ag NPs to the CeO2 film generated by the NPs plasmonic resonance photoexcitation. Ultrafast changes (

Recently, thin-film solar cells have received much attention due to low production cost. However, such cells suffer from low efficiency due to which they cannot be used for practical applications. To cater this problem, we have numerically investigated thin-film tandem solar cells comprising of double active layers made of amorphous silicon (a-Si) and crystalline silicon (c-Si) of different energy bandgaps. The tandem cell is found to absorb large amount of solar photons compared to a single a-Si and c-Si solar cells. To further improve the absorption efficiency, we efficiently utilized the surface plasmon resonance (SPR) effect of plasmonic nanoparticles, which are deposited in the form of a square lattice in the top a-Si active layer. The absorption characteristics of the cell are enhanced and tuned by optimizing the material and size of the nanoparticles. Moreover, periodic disorders are incorporated, which allow mixing of plasmonic modes having different angular momenta, resulting in a super broadband light absorption from 300 to 1100 nm and yielding a short circuit current density of 33.917 mA/cm2 in the active layers. The proposed plasmonic tandem cell can be advantageous for most of the photovoltaic applications.

In this work, a nanoscale device architecture is demonstrated for a UV photodetector application on sapphire (0001), incorporating the plasmonic hybrid nanoparticles (HNPs), graphene quantum dots (GQDs), and titanium oxide (TiO2) for the first time. The hybrid GQDs/TiO2/HNPs photodetector exhibits the photocurrent of 1.58 × 10-5 A under the 1.64 mW/mm2 of 275 nm illumination at 10 V, which is around two order increase from the bare TiO2 device. The proposed architecture demonstrates a low dark current of ∼1 × 10-10 A at 10 V and thus the device demonstrates an excellent photo to dark current ratio along with the improved rise and fall time on the order of several hundred millisecond. The enhanced performance of device architecture is attributed to the efficient utilization of localized surface plasmon resonance (LSPR) induced hot carriers as well as scattered photons from the plasmonic HNPs that are fully encapsulated by the photoactive TiO2 layers. Furthermore, the addition of GQDs on the TiO2 can offer an additional photon absorption pathway. The proposed hybrid architecture of GQDs/TiO2/HNPs demonstrates the integration of the photon absorption and carrier transfer properties of plasmonic HNPs, GQDs, and TiO2 for an enhanced ultraviolet (UV) photoresponse. The photocurrent enhancement mechanisms of the hybrid device architecture are thoroughly investigated based on the finite-difference time domain (FDTD) simulation along with the energy band analysis. This work demonstrates a great potential of the hybrid device architecture for high-performance UV photodetectors.

Matching the resonant wavelength of plasmonic nanoparticles (NPs) and the emission band of organic materials is critical for achieving optimal plasmon-enhanced luminescence in organic light-emitting devices (OLEDs). However, the spectral matching is often unsatisfactory because the interior architecture of OLEDs limits the dimensions of the NPs to support the desired wavelength adjustment. In this article, we proposed a design strategy via AuxAg1−x alloy NPs to enable resonance tuning while preserving the size of the NP to suit the OLED design requirements. The bimetallic NPs, especially for x < 0.6, not only add one more degree of freedom to vary the plasmon wavelength but also provide the benefits of higher scattering and more intense and outspread electric fields over a broader spectrum compared to Au monometallic NPs. These features allow smaller NPs, which are more compatible with OLED interiors, to scatter electric fields more efficiently and increase the density of molecules interacting with the NP plasmons. In the presence of a nearby dipole emitter, the bimetallic NPs can simultaneously increase radiative enhancement and suppress non-radiative losses, which are advantageous for increasing the quantum yield and luminescence efficiency of the emitter. These improvements are associated with lower intraband and interband activities resulting from the higher molar fraction of Ag in the alloy NPs. We provided composition mappings to achieve enhanced luminescence for specified wavelengths at fixed NP sizes. Finally, we theoretically demonstrated that the bimetallic NPs could improve the light-extraction efficiency of OLEDs better than Au monometallic NPs. This work provides essential guidance to enable versatile plasmon-enhanced applications with predefined nanostructural geometries and wavelengths to match the device requirements.

Plasmonic nanoparticles show highly sensitive optical properties upon local dielectric environment changes. Hybridisation of plasmonic nanoparticles with active polymeric materials can allow stimuli-responsive and multiplex sensing over conventional monotonic sensing capacity. Such heterogeneous adlayers around the plasmonic core component, however, are likely to perturb the local refractive index in the nanometre regime and lead to uncertainty in its intrinsic sensitivity. Herein we prepare a series of polystyrene-grafted polyhedral gold nanoparticles, cubic and concave cubic cores, with different edge lengths and polymer thicknesses with precise synthesis control. Their localised surface plasmon resonance (LSPR) spectral changes are monitored to understand the effect of core morphological details in the interplay of nanoscale polymeric shells. Quantitative image analysis of changes in the core and shell shape contours and finite-difference time-domain simulations of the corresponding LSPR spectra and electric field distributions reveal that the magnitude of the LSPR spectral shift is closely dependent on the core morphology, polymer shell thickness and electric field intensity. We also demonstrate that the polystyrene-grafted gold concave cube displays higher sensitivity for nanoscale refractive index change in the polymer shell than the polystyrene-grafted gold cube at different temperatures. Our systematic investigation will help design polymer-composited plasmonic nanosensors for desirable applications.

The control of magnetic properties at the nanoscale is a current topic of intense research. It was shown that combining both magnetic and plasmonic nanoparticles (NPs) led to the improvement of their magneto-optical signal. In this context, common strategies consist of the design of bimetallic NPs. However, the understanding of the physics leading to the coupling between magnetic and plasmonic NPs is lacking, preventing any significant progress for the development of future photonic devices. In this article, we propose to focus our attention on an efficient and commonly used magnetic metal, cobalt, and evaluate its plasmonic properties at the nanoscale through the use of NP regular arrays, as a potential candidate combining both optical and magnetic functionalities within the same metal. We show that such NPs display plasmonic properties within a large spectral range from the UV to the NIR spectral range, with efficient quality factors, when the inter-particle distance is properly selected. These as-fabricated simple materials could find applications in integrated photonic devices for telecommunications.

Designing low-cost and high-performance photoelectrodes with improved light harvesting and charge separation rates is significant in photoelectrochemical water splitting. Here, a novel TiO2/Cu2O/Al/Al2O3 photoelectrode is manufactured by depositing plasmonic nanoparticles of the non-noble metal Al on the surface of a TiO2/Cu2O core/shell heterojunction for the first time. The Al nanoparticles, which exhibit a surface plasmon resonance (SPR) effect and are substantially less expensive than noble metals such as Au and Ag, generate hot electron–hole pairs and amplify the electromagnetic field at the interface under illumination. The as-prepared TiO2/Cu2O/Al/Al2O3 photoelectrodes have an extended absorption range and enhanced carrier separation and transfer. Their photocurrent density of 4.52 mA·cm−2 at 1.23 V vs. RHE represents an 1.84-fold improvement over that of TiO2/Cu2O. Specifically, the ultrathin Al2O3 passivation layer spontaneously generated on the surface of Al in air could act as a protective layer to significantly increase its stability. In this work, the synergistic effect of the heterojunctions and the SPR effect of the non-noble metal Al significantly improve the photoelectrode performance, providing a novel concept for the design of electrodes with good properties and high practicability.

In the present study, the performance improvement of the promising eco-friendly Cu2ZnSnS4 (CZTS) solar cells have been investigated numerically using Al plasmonic nanoparticles. The optical and electrical simulations were performed using the finite-difference time-domain (FDTD) method. It was revealed that loading plasmonic nanoparticles on the topmost layer of the CZTS solar cell leads to light absorption enhancement in the cell. By sweeping the radius of plasmonic nanoparticles from 20 nm to 60 nm, a significant enhancement in the efficiency occurred. The variation of the external quantum efficiency (EQE) and photovoltaic current density–voltage (J–V) curve under air mass of AM1.5 with and without plasmonic nanoparticles were also studied.

In this research work, a systematic design of a novel anti-reflective layer using embedded plasmonic nanoparticles is investigated for a thin-film GaAs solar cell. First, an anti-reflective layer that is made from ITO or SiO2 is assumed in which Al nanoparticles are embedded inside them to manipulate the absorption and hence the photocurrent of a 500-nm GaAs solar cell. It is investigated that the Al nanoparticles embedded inside the anti-reflective coating improve the photocurrent of a GaAs solar cell. For instance, the 15.37 mA photocurrent is obtained for 500-nm bare GaAs cell, and it reached to 17.25 mA/cm2 and 20.18 mA/cm2 when an ITO anti-reflection is used with Al nanoparticles on top and inside that, respectively. It increases to 21.94 mA/cm2 and 24.98 mA/cm2 in the case of the anti-reflective layer made from SiO2 and Al nanoparticles at the top side or inside that, respectively. Finally, using a double anti-reflective layer that is made from SiO2-TiO2, the maximum photocurrents of 23.79 mA/cm2 and 24.68 mA /cm2 are obtained when Al nanoparticles are at the top side or inside that, respectively. The simulation results show that the embedding Al nanoparticles in the anti-reflective layer can improve the photocurrent of a thin-film GaAs solar cell.

The efficiency of thin-film solar cells can be increased considerably by coupling the solar cells with plasmonic nanoparticles. However, while the benefits of utilizing plasmonic nanoparticles has formerly been recognized, the physical properties of the nanoparticles at which the conversion efficiency is optimized have not yet been completely studied. Among the possible properties, this study investigates meticulously the effects of plasmonic nanoparticle shapes and size on the improvement of the energy conversion efficiency of CIGS solar cells. Two different shapes including spheres and cylinders were analyzed in this study. It was revealed that the cylindrical Ag nanoparticles with a diameter of 50 nm and a height of 125 nm placed in an array with period of 215 nm exhibited the most substantial enhancement in the optical absorption and electrical current generation. The achievements in this article have been attained through optical and electrical analysis as well as the near-field imaging studies.

Nanofluids are potential working fluids for Direct Absorption Solar Collectors, mainly due to the enhancement of the optical absorption by the presence of metallic nanoparticle inclusions. For instance, Gold Nanoshells (Au NS) have absorption spectrums in the visible–NIR spectrum that can be tuned controlling their size in the chemical synthesis. The use of metallic nanoheaters in photo-thermal applications requires finding nanostructures with high optical absorption features and low optical scattering properties, which could be achieved by doping gold with transition metals impurities, such as Pt, Fe, or Ag. In this work, a numerical analysis is used to determine the proper fraction of Fe-doping Au NS to increase the solar energy efficiencies of plasmonic nanofluids. In our knowledge, it is the first time this kind of nanofluid is proposed for solar harvesting applications. The results show that the solar weighted absorption efficiency of Fe-doped Au NS based nanofluids is sensibly enhanced and improved the performance of direct solar absorption collectors by increasing the optical absorption cross-section of plasmonic nanoparticles. The collector using Fe-doped gold nanoshells based nanofluids can reach thermal efficiency above 95% at 1 kWm−2, and in a very dilute condition (volume fraction of p = 2 × 1 0 − 5 ). This value is up to 20% superior to that of pure Au NS based working fluids. These results demonstrated that adjusting the proper fraction of Fe as a dopant into the Au layer of nanostructure provides a novel approach to harvesting solar energy flux under optimal conditions.

Over the past two decades, there has been a growing interest in the use of plasmonic nanoparticles as sources of heat remotely controlled by light, giving rise to the field of thermoplasmonics. The ability to release heat on the nanoscale has already impacted a broad range of research activities, from biomedicine to imaging and catalysis. Thermoplasmonics is now entering an important phase: some applications have engaged in an industrial stage, while others, originally full of promise, experience some difficulty in reaching their potential. Meanwhile, innovative fundamental areas of research are being developed. In this Review, we scrutinize the current research landscape in thermoplasmonics, with a specific focus on its applications and main challenges in many different fields of science, including nanomedicine, cell biology, photothermal and hot-electron chemistry, solar light harvesting, soft matter and nanofluidics. Thermoplasmonics is based on the use of plasmonic nanoparticles as sources of heat remotely controlled by light. This Review discusses its current applications and challenges in a broad range of scientific fields, from nanomedicine to hot-electron chemistry and nanofluidics.

Ultrafast laser irradiation can induce morphological and structural changes in plasmonic nanoparticles. Gold nanorods (Au NRs), in particular, can be welded together upon irradiation with femtosecond laser pulses, leading to dimers and trimers through the formation of necks between individual nanorods. We used electron tomography to determine the 3D (atomic) structure at such necks for representative welding geometries and to characterize the induced defects. The spatial distribution of localized surface plasmon modes for different welding configurations was assessed by electron energy loss spectroscopy. Additionally, we were able to directly compare the plasmon line width of single-crystalline and welded Au NRs with single defects at the same resonance energy, thus making a direct link between the structural and plasmonic properties. In this manner, we show that the occurrence of (single) defects results in significant plasmon broadening.

Photoacoustic (PA) imaging is an emerging imaging modality whereby pulsed laser illumination generates pressure transients that are detectable using conventional ultrasound. Plasmonic nanoparticles such as gold nanorods and nanostars are often used as PA contrast agents. The thermoelastic expansion model best describes the PA response from plasmonic nanoparticles: Light absorption causes a small increase in temperature leading to thermoelastic expansion. The conversion of optical energy into pressure waves (p(o)) is dependent on several features: (i) the absorption coefficient (μ(a)), (ii) the thermal expansion coefficient (β), (iii) specific heat capacity (C(p)) of the absorbing material, (iv) speed of sound in the medium (c), and (v) the illumination fluence (F). Controlling the geometry, composition, coatings, and solvents around plasmonic nanostructures can help tune these variables to generate the optimum PA signal. The thermoelastic expansion model is not limited to plasmonic structures and holds true for all absorbing molecules. Here, we focus on ways to engineer these variables to enhance the PA response from plasmonic nanoparticles.

Plasmonic nanoparticles (NPs) hold tremendous promise for catalyzing light-driven chemical reactions. The conventionally assumed detrimental absorption loss from plasmon damping can now be harveste...

Ag@SnO2 nanoparticles (NPs) have been prepared by varying the concentration of sodium stannate trihydrate coated onto ZnO nanorods as the photoanode for photoelectrochemical self-powered ultraviolet photodetectors (UVPDs). Their structure, morphology, and optical properties were investigated. Compared with ZnO nanorods (NRs), the Ag@SnO2-coated ZnO NRs exhibited ultraviolet photoluminescence enhanced by nearly six orders of magnitude when 2 mL 40 mM sodium stannate trihydrate was used. This enhanced photoluminescence intensity is ascribed to the localized surface plasmon resonance of Ag in Ag@SnO2. Moreover, when varying the sodium stannate trihydrate concentration in the Ag@SnO2 NPs, the UVPD with 2 mL 40 mM sodium stannate trihydrate exhibited a high photocurrent density (Jsc) of 5.81 mA cm−2 compared with 2.34 mA cm−2 for the ZnO UVPD. This boost in Jsc is attributed to enhanced UV light harvesting and reduced charge recombination. Furthermore, this device also reached a high on/off ratio of 3885 and fast response time compared with the ZnO UVPD. Finally, such photoanodes formed from Ag@SnO2 nanoparticles coated on ZnO NRs are promising for use in photoelectrochemical-type self-powered UV photodetectors.

Spectroscopic ellipsometry was used to check plasmonic properties of thin annealed gold films depending on the thickness of the annealed films and parameters of the annealing. It is demonstrated that the position of the plasmonic resonance is defined by the size of produced nanoparticles together with the strength of interparticle interactions. It is shown that the account of interparticle interactions is necessary for the correct description of optical properties of layers of plasmonic nanoparticles.

Plasmonic photocatalysis is among the most efficient processes for the photoreduction of CO2 into valuable fuels. The formation of localized surface plasmon resonance (LSPR), energy transfer, and surface reaction are the significant steps in this process. LSPR plays an essential role in the performance of plasmonic photocatalysts as it promotes an excellent, light absorption over a broad wavelength range while simultaneously facilitating an efficient energy transfer to semiconductors. The LSPR transfers energy to a semiconductor through various mechanisms, which have both advantages and disadvantages. This work points out four critical features for plasmonic photocatalyst design, that is, plasmonic materials, size, shape of plasmonic nanoparticles (PNPs), and the contact between PNPs and semiconductor. Various developed plasmonic photocatalysts, as well as their photocatalytic performance in CO2 photoreduction, are reviewed and discussed. Finally, perspectives of advanced architectures and structural engineering for plasmonic photocatalyst design are put forward with high expectations to achieve an efficient CO2 photoreduction shortly.

Three-dimensional (3D) plasmonic structures have attracted great attention because abnormal wetting behavior of plasmonic nanoparticles (NPs) on 3D nanostructure can enhance the localized surface plasmons (LSPs). However, previous 3D plasmonic nanostructures inherently had weak plasmonic light absorption, low electrical conductivity, and optical transmittance. Here, we fabricated a novel 3D plasmonic nanostructure composed of Ag NPs as the metal for strong LSPs and 3D nano-branched indium tin oxide (ITO BRs) as a transparent and conductive framework. The Ag NPs formed on the ITO BRs have a more dewetted behavior than those formed on the ITO films. We experimentally investigated the reasons for the dewetting behavior of Ag NPs concerning the geometry of ITO BRs. The spherical Ag NPs are spatially separated and have high density, thereby resulting in strong LSPs. Finite-domain time-difference simulation evidenced that spatially-separated, high-density and spherical Ag NPs formed on ITO BRs dramatically boost the localized electric field in the active layer of organic solar cells (OSCs). Photocurrent of PTB7:PCBM OSCs with the ITO BRs/Ag NPs increased by 14%.

We report on the numerical demonstration of enhanced second harmonic generation (SHG) originating from collective resonances in plasmonic nanoparticle arrays. The nonlinear optical response of the metal nanoparticles is modeled by employing a hydrodynamic nonlinear Drude model implemented into Finite-Difference Time-Domain (FDTD) simulations, and effective polarizabilities of nanoparticle multipoles in the lattice are analytically calculated at the fundamental wavelength by using a coupled dipole–quadrupole approximation. Excitation of narrow collective resonances in nanoparticle arrays with electric quadrupole (EQ) and magnetic dipole (MD) resonant coupling leads to strong linear resonance enhancement. In this work, we analyze SHG in the vicinity of the lattice resonance corresponding to different nanoparticle multipoles and explore SHG efficiency by varying the lattice periods. Coupling of electric quadrupole and magnetic dipole in the nanoparticle lattice indicates symmetry breaking and the possibility of enhanced SHG under these conditions. By varying the structure parameters, we can change the strength of electric dipole (ED), EQ, and MD polarizabilities, which can be used to control the linewidth and magnitude of SHG emission in plasmonic lattices. Engineering of lattice resonances and associated magnetic dipole resonant excitations can be used for spectrally narrow nonlinear response as the SHG can be enhanced and controlled by higher multipole excitations and their lattice resonances. We show that both ED and EQ–MD lattice coupling contribute to SHG, but the presence of strong EQ–MD coupling is important for spectrally narrow SHG and, in our structure, excitation of narrow higher-order multipole lattice resonances results in five times enhancement.

The influence of different types of plasmonic gold (Au-NPs) and silver (Ag-NPs) nanoparticles as well as aging on the performance of Surface-Enhanced Raman Scattering (SERS) sensors were studied. The average diameters of Au-NPs and Ag-NPs were about 23 nm and 15 nm, respectively, with a number of laser pulses of about 200. plasmonic nanoparticles were synthesized by laser ablation process in distilled water using a fixed energy laser fluence of about 14 J/cm2 of Nd-YAG laser, with 1060 nm wavelength and 1 Hz pulse repetition rate. The SERS sensor was carried out by quick drop casting process of plasmonicplasmonic nanoparticles on glass substrates. The morphological aspects and the performance of SERS sensors were investigated by high resolution transmission electron microscopy (HR-TEM) and Raman spectroscopy. All the results indicated the significant dependence of the performance of the sensor on the types of the plasmonic nanoparticles . The obtained Raman signal intensity of Ag-NPs was about 105a.u. compared with 103a.u. for Au-NPs. While, the stability of Au-NPs was much higher than that of Ag-NPs based on SERS sensors due to the normal oxidation process of Ag-NPs.

A transparent display allows us to see both the projection image displayed on it and the view behind it at the same time, which can be widely used in the car windshield, shop windows, and so on. To achieve the transparent display with the simple and easily available plasmonic nanoparticles, plasmonic Au-Ag nanoparticles with the strong scattering ability were used to achieve the objective of selectively scattering red, blue, and green light for the transparent screen in this work. Firstly, the optimized size parameters for these three color transparent displays were obtained theoretically. On the other hand, plasmonic nanoparticles used for the blue and green color transparence screen were reported in the previous experiments. Finally, a red color transparent display with the wide viewing angle was made based on the optimized Au nanoparticles experimentally.

Recently, plasmonic nanofluids (i.e., a suspension of plasmonic nanoparticles in a base fluid) have been widely employed in direct-absorption solar collectors because the localized surface plasmon supported by plasmonic nanoparticles can greatly improve the direct solar thermal conversion performance. Considering that the surface plasmon resonance frequency of metallic nanoparticles, such as gold, silver, and aluminum, is usually located in the ultraviolet to visible range, the absorption coefficient of a plasmonic nanofluid must be spectrally tuned for full utilization of the solar radiation in a broad spectrum. In the present study, a modern design process in the form of a genetic algorithm (GA) is applied to the tailoring of the spectral absorption coefficient of a plasmonic nanofluid. To do this, the major components of a conventional GA, such as the gene description, fitness function for the evaluation, crossover, and mutation function, are modified to be suitable for the inverse problem of tailoring the spectral absorption coefficient of a plasmonic nanofluid. By applying the customized GA, we obtained an optimal combination for a blended nanofluid with the desired spectral distribution of the absorption coefficient, specifically a uniform distribution, solar-spectrum-like distribution, and a step-function-like distribution. The resulting absorption coefficient of the designed plasmonic nanofluid is in good agreement with the prescribed spectral distribution within about 10\% to 20\% of error when six types of nanoparticles are blended. Finally, we also investigate how the inhomogeneous broadening effect caused by the fabrication uncertainty of the nanoparticles changes their optimal combination., 4 figures

Theoretical guidance on the optical properties of plasmonic nanoparticles (NPs) is of significant importance in tremendous numbers of fields like photovoltaics. The incorporation of plasmonic NPs into photovoltaic material can promote optical absorption either via the excitation of localized surface plasmon resonance (LSPR) modes or due to multiple light scattering. Since most fabrication techniques for the incorporation of NPs into photovoltaic material result in a random array of NPs with various sizes, numerical simulations based on solving the Maxwell equations are computationally expensive and prohibitively slow for this large number of NPs. Therefore, in this paper, based on modified effective medium theories, taking into account finite size of NPs, size dispersion for NPs, extrinsic dynamic effect, and intrinsic confinement effect, fast and cost-effective analytical modeling, considering both LSPR and scattering effects, is presented to obtain the optical properties of photovoltaic material incorporated by spherical NPs with nonuniform size and random distribution. Then, by means of presented analytical modeling, considering reasonably low and high volume fractions of NPs in addition to small and large size of NPs, the effect of different parameters of embedded NPs into organic and inorganic photovoltaic materials is explored.

Plasmonic nanoparticles are well-known for their properties of electromagnetic field enhancement and surface spectroscopy enhancement. We used the plasmon hybridization method and group theory to s...

Near-infrared (NIR) radiation contains about half of the solar radiation energy. After passing through a window, it does not participate in natural light and causes the room to overheat. Light-transparent infrared (IR) filters do not pass this radiation. The use of dispersed plasmon nanoparticles (NPs), which attenuate transmitted radiation due to localized plasmon resonance, is an economical method for manufacturing IR filters. As a result of the generalization of the data, it is found that the best properties for attenuating NIR radiation are possessed by copper monosulfide NPs doped with cesium oxide tungsten bronzes and lanthanum hexaboride. The characteristics of commercial samples used to manufacture light-transparent infra-red filters in the form of films, plastic sheets, and laminated glass are given.

We present the first experimental evidence for the influence of the fifth-order nonlinearity on the characteristics of Random Lasers with plasmonic nanoparticles as scatterers. The experiments were...

It is now believed that the near-resonance excitation of plasmonic nanoparticles is necessary to increase the Raman signal of nearby molecules. Consequently, for surface-enhanced Raman scattering (...

Fine-needle aspiration cytology is a minimally invasive diagnostic strategy. However, collected specimens have to undergo a series of complex preparation steps, thus limiting the use of fine-needle...

The deposition of an atomically precise nanocluster, for example, Ag44(SR)30, onto a large‐band‐gap semiconductor such as TiO2 allows a clear interface to be obtained to study charge transfer at the interface. Changing the light source from visible light to simulated sunlight led to a three orders of magnitude enhancement in the photocatalytic H2 generation, with the H2 production rate reaching 7.4 mmol h−1 gcatalyst −1. This is five times higher than that of TiO2 modified with Ag nanoparticles and even comparable to that of TiO2 modified with Pt nanoparticles under similar conditions. Energy band alignment and transient absorption spectroscopy reveal that the role of the metal clusters is different from that of both organometallic complexes and plasmonic nanoparticles: A type II heterojunction charge‐transfer route is achieved under UV/Vis irradiation, with the cluster serving as a small‐band‐gap semiconductor. This results in the clusters acting as co‐catalysts rather than merely photosensitizers., Multitasking: Metal nanoclusters are not merely photosensitizers, they can also act as co‐catalysts under appropriate conditions. Deposition of the atomically precise nanocluster Ag44(thiolate)30 onto a large‐band‐gap semiconductor such as TiO2 led to a type II heterojunction charge‐transfer route being achieved on irradiation with UV/Vis light, with the cluster serving as a small‐band‐gap semiconductor, rather than merely a photosensitizer.

The gap length between plasmonic nanoparticles determines the strength of the optical coupling that results in electromagnetic field enhancement for spectroscopic and other applications. Although g...

Although the drawing of plasmonic images attracts attention, both top-down lithographic methods and bottom-up laser ablation methods require expensive equipment. In the present work, a cost-effecti...

The objective of this study is to enhance the efficiency of copper indium gallium selenide (CIGS) solar cells. To accomplish that, composition grading of absorber layer was carried out by using SILVACO’s technology aided computer design (TCAD) ATLAS program. Results showed a meaningful improvement of output parameters including open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF), and power conversion efficiency (η). For further performance improvement of the cell, Au plasmonic scattering nanoparticles were loaded on the top of the ZnO window layer. Plasmonic nanoparticles can restrict, absorb, navigate, or scatter the incident light. By using the spherical Au nanoparticles, a very good increase in the light absorption in the cell over the reference planar CIGS solar cell was observed. The highest η = 19.01% was achieved for the designed ultra-thin bandgap-graded CIGS solar cell decorated by Au nanoparticles.

In this work, we propose using periodic Au nanoparticles (NPs) in indium selenide-based optoelectronic devices to tune the optical absorption of indium selenide. Electromagnetic simulations show that optical absorption of indium selenide can be manipulated by tuning plasmonic resonance. The effect on the plasmonic resonance of the size, period of NPs, the thickness of silicon oxide, and the insulator spacer is systematically analyzed. A high absorption enhancement over the visible spectrum is achieved through systematic optimization of nanostructures.