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Item type:Publication, Access status: without files , Spatially encoded polaritonic ultra-strong coupling in gradient metasurfaces with epsilon-near-zero modes(2025-09-12)23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Confined Flash Printing and Synthesis of Stable Perovskite Nanofilms under Ambient Conditions(2024-11-14); ; ; The fabrication of stable perovskite nanofilm patterns is important for the development of functional optical devices. However, current production approaches are limited by the requirement for strict inert gas protection and long processing times. Here, a confined flash printing synthesis method is presented to generate perovskite nanofilms under ambient conditions, combining precursor transfer, perovskite synthesis, crystallization, and polymer protection in a single step within milliseconds. A laser simultaneously prints and induces the flash synthesis, confined in a polymer nanofilm, under normal ambient conditions. Due to its simplicity and flexibility, the method enables the combination and screening of many different perovskite precursor materials on various substrates. Besides for the development of novel perovskite materials and devices, the nanofilms can be applied for biodetection. The unique H<inf>2</inf>O<inf>2</inf>-responsive property of the ultrathin perovskite quantum dot film is applied for biomolecule detection based on oxidase-catalyzed enzymatic reactions.Publicationtype: Journal Article12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Accounting for the quantum capacitance of graphite in constant potential molecular dynamics simulations(Wiley-VCH, 2024-08-03); ; ; Molecular dynamics (MD) simulations at a constant electric potential are an essential tool to study electrochemical processes, providing microscopic information on the structural, thermodynamic, and dynamical properties. Despite the numerous advances in the simulation of electrodes, they fail to accurately represent the electronic structure of materials such as graphite. In this work, a simple parameterization method that allows to tune the metallicity of the electrode based on a quantum chemistry calculation of the density of states (DOS) is introduced. As a first illustration, the interface between graphite electrodes and two different liquid electrolytes, an aqueous solution of NaCl and a pure ionic liquid, at different applied potentials are studied. It is shown that the simulations reproduce qualitatively the experimentally-measured capacitance; in particular, they yield a minimum of capacitance at the point of zero charge (PZC), which is due to the quantum capacitance (QC) contribution. An analysis of the structure of the adsorbed liquids allows to understand why the ionic liquid displays a lower capacitance despite its large ionic concentration. In addition to its relevance for the important class of carbonaceous electrodes, this method can be applied to any electrode materials (e.g. 2D materials, conducting polymers, etc), thus enabling molecular simulation studies of complex electrochemical devices in the future.Publicationtype: Journal Article28 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Revealing mode formation in quasi-bound states in the continuum metasurfaces via near-field optical microscopy(Wiley-VCH, 2024-08-02); Barkey, MartinPhotonic metasurfaces offer exceptional control over light at the nanoscale, facilitating applications spanning from biosensing, and nonlinear optics to photocatalysis. Many metasurfaces, especially resonant ones, rely on periodicity for the collective mode to form, which makes them subject to the influences of finite size effects, defects, and edge effects, which have considerable negative impact at the application level. These aspects are especially important for quasi-bound state in the continuum (BIC) metasurfaces, for which the collective mode is highly sensitive to perturbations due to high-quality factors and strong near-field enhancement. Here, the mode formation in quasi-BIC metasurfaces on the individual resonator level using scattering scanning near-field optical microscopy (s-SNOM) in combination with a new image processing technique, is quantitatively investigated. It is found that the quasi-BIC mode is formed at a minimum size of 10 × 10-unit cells much smaller than expected from far-field measurements. Furthermore, it is shown that the coupling direction of the resonators, defects and edge states have pronounced influence on the quasi-BIC mode. This study serves as a link between the far-field and near-field responses of metasurfaces, offering crucial insights for optimizing spatial footprint and active area, holding promise for augmenting applications such as catalysis and biospectroscopy.Publicationtype: Journal Article5 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Customized Enhancement of Thermal Sensitivity of Tumors at Different Subcutaneous Depths by Multichannel Lanthanide Nanocomposites(2024-06-06); ; 9 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Recyclable and Robust Optical Nanoprobes with Engineered Enzymes for Sustainable Serodiagnostics(2023-11-23); ; 7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Iridium-based selective emitters for thermophotovoltaic applications(Elsevier, 2023-10-12); ; ; ; Raudsepp, RagleThe long-term operation of refractory-metal-based metamaterials is crucial for applications such as thermophotovoltaics. The metamaterials based on refractory metals like W, Mo, Ta, Nb, and Re fail primarily by oxidation. Here, the use of the noble metal Ir is proposed, which is stable to oxidation and has optical properties comparable to gold. The thermal endurance of Ir in a 3-layer-system, consisting of HfO2/Ir/HfO2, by performing annealing experiments up to 1240 °C in a pressure range from 2 × 10−6 mbar to 1 bar, is demonstrated. The Ir layer shows no oxidation in a vacuum and inert gas atmosphere. At temperatures above 1100 °C, the Ir layer starts to agglomerate due to the degradation of the confining HfO2 layers. An in situ X-ray diffraction experimental comparison between 1D multilayered Ir/HfO2 and W/HfO2 selective emitters annealed at 1000 °C, 2 × 10−6 mbar, over 100 h, confirms oxidation stability of Ir while W multilayers gradually disappear. The results of this work show that W-based metamaterials are not long-term stable even at 1000 °C. However, the oxidation resistance of Ir can be leveraged for refractory plasmonic metamaterials, such as selective emitters in thermophotovoltaic systems with strong suppression of long wavelength radiation.Publicationtype: Journal ArticleScopus© Citations 6 30 92 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Metasurface-Enhanced Infrared Spectroscopy: An Abundance of Materials and Functionalities(2023-08-24); 6 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , High-Q nanophotonics over the full visible spectrum enabled by hexagonal boron Nitride metasurfaces(Wiley-VCH, 2023-02-21); ; Watanabe, KenjiAll-dielectric optical metasurfaces with high quality (Q) factors have been hampered by the lack of simultaneously lossless and high-refractive-index materials over the full visible spectrum. In fact, the use of low-refractive-index materials is unavoidable for extending the spectral coverage due to the inverse correlation between the bandgap energy (and therefore the optical losses) and the refractive index (n). However, for Mie resonant photonics, smaller refractive indices are associated with reduced Q factors and low mode volume confinement. Here, symmetry-broken quasi bound states in the continuum (qBICs) are leveraged to efficiently suppress radiation losses from the low-index (n ≈ 2) van der Waals material hexagonal boron nitride (hBN), realizing metasurfaces with high-Q resonances over the complete visible spectrum. The rational use of low- and high-refractive-index materials as resonator components is analyzed and the insights are harnessed to experimentally demonstrate sharp qBIC resonances with Q factors above 300, spanning wavelengths between 400 and 1000 nm from a single hBN flake. Moreover, the enhanced electric near fields are utilized to demonstrate second-harmonic generation with enhancement factors above 10². These results provide a theoretical and experimental framework for the implementation of low-refractive-index materials as photonic media for metaoptics.Publicationtype: Journal Article12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Automated Laser-Transfer Synthesis of High-Density Microarrays for Infectious Disease Screening(2022-06-01); ; ; Laser-induced forward transfer (LIFT) is a rapid laser-patterning technique for high-throughput combinatorial synthesis directly on glass slides. A lack of automation and precision limits LIFT applications to simple proof-of-concept syntheses of fewer than 100 compounds. Here, an automated synthesis instrument is reported that combines laser transfer and robotics for parallel synthesis in a microarray format with up to 10 000 individual reactions cm<sup>−</sup><sup>2</sup>. An optimized pipeline for amide bond formation is the basis for preparing complex peptide microarrays with thousands of different sequences in high yield with high reproducibility. The resulting peptide arrays are of higher quality than commercial peptide arrays. More than 4800 15-residue peptides resembling the entire Ebola virus proteome on a microarray are synthesized to study the antibody response of an Ebola virus infection survivor. Known and unknown epitopes that serve now as a basis for Ebola diagnostic development are identified. The versatility and precision of the synthesizer is demonstrated by in situ synthesis of fluorescent molecules via Schiff base reaction and multi-step patterning of precisely definable amounts of fluorophores. This automated laser transfer synthesis approach opens new avenues for high-throughput chemical synthesis and biological screening.Publicationtype: Journal Article8