Semitransparent organic photovoltaics (ST‐OPVs) offer promising prospects for application in building‐integrated photovoltaic systems and greenhouses, but further improvement of their performance ...faces a delicate trade‐off between the two competing indexes of power conversion efficiency (PCE) and average visible transmittance (AVT). Herein, the authors take advantage of coupling plasmonics with the optical design of ST‐OPVs to enhance near‐infrared absorption and hence simultaneously improve efficiency and visible transparency to the maximum extent. By integrating core–bishell PdCu@Au@SiO2 nanotripods that act as optically isotropic Lambertian sources with near‐infrared‐customized localized surface plasmon resonance in an optimal ternary PM6:BTP‐eC9:L8‐BO‐based ST‐OPV, it is shown that their interplay with a multilayer optical coupling layer, consisting of ZnS(130 nm)/Na3AlF6(60 nm)/WO3(100 nm)/LaF3(50 nm) identified from high‐throughput optical screening, leads to a record‐high PCE of 16.14% (certified as 15.90%) along with an excellent AVT of 33.02%. The strong enhancement of the light utilization efficiency by ≈50% as compared to the counterpart device without optical engineering provides an encouraging and universal pathway for promoting breakthroughs in ST‐OPVs from meticulous optical design.
Core–bishell PdCu@Au@SiO2 nanotripods significantly enhance photon absorption in the NIR range for semi‐transparent organic solar cells. An optical coupling multilayer consisting of ZnS(130 nm)/Na3AlF6(60 nm)/WO3(100 nm)/LaF3(50 nm) enhances the NIR light utilization and the visible transparency. These strategies result in a record‐high PCE of 16.14% along with an excellent AVT of over 30%, correspond to the record LUE of 5.33%.
Self‐assembled plasmonic metamaterials are fabricated from silver nanoparticles covered with a silica shell. These metamaterials demonstrate topological darkness or selective suppression of ...reflection connected to global properties of the Fresnel coefficients. The optical properties of the studied structures are in good agreement with effective medium theory. The results suggest a practical way of achieving high phase sensitivity in plasmonic metamaterials.
The design and chemical synthesis of plasmonic nanoresonators exhibiting a strong magnetic response in the visible is a key requirement to the realization of efficient functional and self-assembled ...metamaterials. However, novel applications like Huygens’ metasurfaces or mu-near-zero materials require stronger magnetic responses than those currently reported. Our numerical simulations demonstrate that the specific dodecahedral morphology, whereby 12 silver satellites are located on the faces of a nanosized dielectric dodecahedron, provides sufficiently large electric and magnetic dipolar and quadrupolar responses that interfere to produce so-called generalized Huygens’ sources, fulfilling the generalized Kerker condition. Using a multistep colloidal engineering approach, we synthesize highly symmetric plasmonic nanoclusters with a controlled silver satellite size and show that they exhibit a strong forward scattering that may be used in various applications such as metasurfaces or perfect absorbers.
Abstract
Nanoshells made of a silica core and a gold shell possess an optical response that is sensitive to nanometer-scale variations in shell thickness. The exponential red shift of the plasmon ...resonance with decreasing shell thickness makes ultrathin nanoshells (less than 10 nm) particularly interesting for broad and tuneable ranges of optical properties. Nanoshells are generally synthesised by coating gold onto seed-covered silica particles, producing continuous shells with a lower limit of 15 nm, due to an inhomogeneous droplet formation on the silica surface during the seed regrowth. In this paper, we investigate the effects of three variations of the synthesis protocol to favour ultrathin nanoshells: seed density, polymer additives and microwave treatment. We first maximised gold seed density around the silica core, but surprisingly its effect is limited. However, we found that the addition of polyvinylpyrrolidone during the shell synthesis leads to higher homogeneity and a thinner shell and that a post-synthetic thermal treatment using microwaves can further smooth the particle surface. This study brings new insights into the synthesis of metallic nanoshells, pushing the limits of ultrathin shell synthesis.
The process of convectively self-assembling particles in films suffers from low reproducibility due to its high dependency on particle concentration, as well as a variety of interactions and physical ...parameters. Inhomogeneities in flow rates and instabilities at the air–liquid interface are mostly responsible for reproducibility issues. These problems are aggravated by adding multiple components to the dispersion, such as binary solvent mixtures or surfactant/polymer additives, both common approaches to control stick-slip behavior. When an additive is used, not only does it change the surface tension, but also the viscosity and the evaporation rate. Worse yet, gradients in these three properties can form, which then lead to Marangoni currents. Here, we use a series of alcohols to study the role of viscosity independently of other solvent properties, to show its impact on stick-slip behavior and interband distances. We show that mixtures of glycerol and alcohol or poly(acrylic acid) and alcohol lead to more complex patterning. Marangoni currents are not always observed in co-solvent systems, being dependent on the rate of solvent evaporation. To produce homogeneous particle assemblies and control stick-slip behavior, gradients must be avoided, and the surface tension and viscosity need both be carefully controlled.
We examined the potential of silver nanocubes to achieve sintered conductive junctions for applications in microelectronics and die-attach bonding devices. For such applications, it remains a ...challenge to achieve dense and robust joints, sintered at low temperature (<200 °C). The minimum sintering temperature is strongly dependent on the particle shape, interparticle distance, and surface energy. In this respect, nanocubes offer two advantages over nanospheres: a higher proportion of surface atoms and the ability to assemble into denser 3D colloidal packings. Here, we used a colloidal approach to create joints using 3D close-packed arrays of silver nanocubes of different edge lengths (from 20 to 60 nm). Starting from monodisperse nanocubes, we assembled them into close-packed supercrystals by drop-casting and investigated their thermal stability and electrical properties on silicon nitride substrates. Spectroscopic measurements allowed a correlation of the plasmonic signature with the length and the degree of corner curvature of the cubes. Using electron microscopy and electrical measurements, we studied the impact of the nanocube size on the sintering temperature and electric properties of the self-organized arrays. The small gaps between the building units yielded uniform sintered patterns possessing high electrical conductivity. More broadly, our approach shows how Ag particles featuring a high density of low-coordination surface atoms, separated by small gaps, increase the efficiency of sintered Ag technology for microelectronics.
•Preparation and characterization of Pd NPs/C and PdO NPs/C catalysts.•Discovery of the peculiar recycling properties of the PdO NPs/C catalyst.•The work addresses the issue of catalyst deactivation ...for the Sonogashira reaction.•Good to high yields of products were obtained with the PdO NPS/C catalyst.•This work expands the synthetic utility of heterogeneous Pd catalysts.
The enhanced recycling properties of 5% PdO NPs/C compared to 5% Pd NPs/C catalyst for the Sonogashira reaction has been unveiled. A simple preparation procedure for 5% Pd NPs/C and 5% PdO NPs/C catalysts is described along with their extensive characterizations. The correlation between the catalyst deactivation and a high content of reduced palladium species for the alkynylation of aryl iodides has been clearly identified with the monitoring of the Pd(0)/Pd(II) ratio over the recycling runs through X-ray photoelectron spectroscopy.
We investigated the acoustic vibrations of gold nanobipyramids and bimetallic gold–silver core–shell bipyramids, synthesized by wet chemistry techniques, using a high-sensitivity pump–probe ...femtosecond setup. Three modes were observed and characterized in the gold core particles for lengths varying from 49 to 170 nm and diameters varying from 20 to 40 nm. The two strongest modes have been associated with the fundamental extensional and its first harmonic, and a weak mode has been associated with the fundamental radial mode, in very good agreement with numerical simulations. We then derived linear laws linking the periods to the dimensions both experimentally and numerically. To go further, we investigated the evolution of these modes under silver deposition on gold core bipyramids. We studied the evolution of the periods of the extensional modes, which were found to be in good qualitative agreement with numerical simulations. Moreover, we observed a strong enhancement of the radial mode amplitude when silver is deposited: we are typically sensitive to the deposition of 40 attograms of silver per gold core particle. This opens up possible applications in the field of mass sensing, where metallic nanobalances have an important role to play, taking advantage of their robustness and versatility.
Original titania nanocages are fabricated from sacrificial silica/polystyrene tetrapod‐like templates. Here the template synthesis, titania deposition and nanocage development through polystyrene ...dissolution and subsequent silica etching are described. Discussion about the competitive deposition of titania on the biphasic templates is particularly emphasized. The morphology of the nanocages is investigated by TEM, STEM, EDX mapping and electron tomography.
Etch‐a‐sketch: Titania nanocages were fabricated by simultaneously carving their hollow core and their four open windows from tetrapod‐like silica/polystyrene templates.
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