Super-Resolution Imaging with Patchy Microspheres

The diffraction limit is a fundamental barrier in optical microscopy, which restricts the smallest resolvable feature size of a microscopic system. Microsphere-based microscopy has proven to be a promising tool for challenging the diffraction limit. Nevertheless, the microspheres have a low imaging contrast in air, which hinders the application of this technique. In this work, we demonstrate that this challenge can be effectively overcome by using partially Ag-plated microspheres. The deposited Ag film acts as an aperture stop that blocks a portion of the incident beam, forming a photonic hook and an oblique near-field illumination. Such a photonic hook significantly enhanced the imaging contrast of the system, as experimentally verified by imaging the Blu-ray disc surface and colloidal particle arrays

Boron nitride-doped polyphenylenic organogels

Herein, we describe the synthesis of the first boron nitride-doped polyphenylenic material obtained through a [4 + 2] cycloaddition reaction between a triethynyl borazine unit and a biscyclopentadienone derivative, which undergoes organogel formation in chlorinated solvents (the critical jellification concentration is 4% w/w in CHCl3). The polymer has been characterized extensively by Fourier-transform infrared spectroscopy, solid-state 13C NMR, solid-state 11B NMR, and by comparison with the isolated monomeric unit. Furthermore, the polymer gels formed in chlorinated solvents have been thoroughly characterized and studied, showing rheological properties comparable to those of polyacrylamide gels with a low crosslinker percentage. Given the thermal and chemical stability, the material was studied as a potential support for solid-state electrolytes. showing properties comparable to those of polyethylene glycol-based electrolytes, thus presenting great potential for the application of this new class of material in lithium-ion batteries

Carbonyl-Based π-Conjugated Materials: From Synthesis to Applications in Lithium-Ion Batteries

The constant growth in the global energy demand together with the increasing awareness of clean and sustainable development has strongly pushed scientists to search for metalfree, low-cost, environmentally friendly functional energy-storage systems (ESSs). Among the reported organic electrode materials, carbonyl-based π-conjugated compounds show excellent rate capabilities and cycling stabilities and are powerful candidates for the next generation of rechargeable lithium-ion batteries (LIBs). Benefiting from the molecular structure versatility and design feasibility, the electrochemical properties of organic and polymeric materials can be easily tuned. This Review summarizes recent efforts in the search for carbonylbased π-conjugated electrode materials in LIBs with a focus on the synthetic strategies developed to improve their electrochemical performance. The use of these materials in flexible, allorganic LIBs is highlighted as a unique direction towards widespread applications of LIBs

Photoactive Boron-Nitrogen-Carbon Hybrids: From Azo-borazines to Polymeric Materials

International audienceIn this paper, we describe synthetic routes for preparing a novel switchable BNC-based chromophore, composed of a borazine core peripherally functionalized with azobenzene moieties. Capitalizing on the Pd-catalyzed Suzuki cross-coupling reaction between a tris-triflate borazine and an organoboron azobenzene derivative, a photoswtichable azo-borazine derivative was successfully prepared. The molecule showed reversible E/Z photoisomerization upon irradiation at the maximum of the intense π–π* absorption feature (360 nm). X-ray crystallographic investigations revealed a nonplanar orientation of the three azobenzene moieties and the trans configuration of the −N═N– bonds. Building on the synthetic versatility of the borazine-azobenzene derivative, we used this photoactive scaffold to engineer soluble BN-doped polythiophene polymers. Photophysical characterization performed in solvents of different polarity suggested that the polymer undergoes intramolecular charge transfer (ICT)

Boron-nitrogen doped carbon scaffolding:Organic chemistry, self-assembly and materials applications of borazine and its derivatives

Discovered by Stock and Pohland in 1926, borazine is the isoelectronic and isostructural inorganic analogue of benzene, where the C[double bond, length as m-dash]C bonds are substituted by B–N bonds. The strong polarity of such heteroatomic bonds widens the HOMO–LUMO gap of the molecule, imparting strong UV-emitting/absorption and electrical insulating properties. These properties make borazine and its derivatives valuable molecular scaffolds to be inserted as doping units in graphitic-based carbon materials to tailor their optoelectronic characteristics, and specifically their semiconducting properties. By guiding the reader through the most significant examples in the field, in this feature paper we describe the past and recent developments in the organic synthesis and functionalisation of borazine and its derivatives. These boosted the production of a large variety of tailored derivatives, broadening their use in optoelectronics, H2 storage and supramolecular functional architectures, to name a few

Plasmon-Driven Electrochemical Methanol Oxidation on Gold Nanohole Electrodes

Direct methanol oxidation is expected to play a central role in low-polluting future power sources. However, the sluggish and complex electro-oxidation of methanol is one of the limiting factors for any practical application. To solve this issue, the use of plasmonic is considered as a promising way to accelerate the methanol oxidation reaction. In this study, we report on a novel approach for achieving enhanced methanol oxidation currents. Perforated gold thin film anodes were decorated with Pt/Ru via electrochemical deposition and investigated for their ability for plasmon-enhanced electrocatalytic methanol oxidation in alkaline media. The novel methanol oxidation anode (AuNHs/PtRu), combining the strong light absorption properties of a gold nanoholes array-based electrode (AuNHs) with surface-anchored bimetallic Pt/Ru nanostructures, known for their high activity toward methanol oxidation, proved to be highly efficient in converting methanol via the hot holes generated in the plasmonic electrode. Without light illumination, AuNHs/PtRu displayed a maximal current density of 13.7 mA/cm2 at −0.11 V vs Ag/AgCl. Enhancement to 17.2 mA/cm2 was achieved under 980 nm laser light illumination at a power density of 2 W/cm2. The thermal effect was negligible in this system, underlining a dominant plasmon process. Fast generation and injection of charge carriers were also evidenced by the abrupt change in the current density upon laser irradiation. The good stability of the interface over several cycles makes this system interesting for methanol electro-oxidation

Boron-Nitride-Carbon Organogels

Heteroatom-doping or peripheral addition of functional groups are the major strategies used to enrich the chemical and physical properties of the polyphenylene-based frameworks. In this work, we describe the synthesis of the first BN-doped polyphenylenic material obtained through a decarbonylative [4 + 2] Diels-Alder cyclo-addition reaction between a tri-ethynylborazine unit and a bis-cyclopentadienone derivative. The BN-polymer was extensively characterized by FT-IR, solid-state C- and B-NMR and by comparison with the isolated monomeric unit. Given the unique thermal and chemical properties, the material was studied as potential support for solid state electrolytes, thus presenting great potential for the application of this new class of materials in lithium-ion batteries