International audienceAn ultrashort laser-assisted method for fast production of concentrated aqueous solutions of ultrapure Si-based colloidal nanoparticles is reported. The method profits from the 3D geometry of femtosecond laser ablation of water-dispersed microscale colloids, prepared preliminarily by the mechanical milling of a Si wafer, in order to avoid strong concentration gradients in the ablated material and provide similar conditions of nanocluster growth within a relatively large laser caustics volume. We demonstrate the possibility for the fast synthesis of non-aggregated, low-size-dispersed, crystalline Si-based nanoparticles, whose size and surface oxidation can be controlled by changing the initial microcolloid concentration and the amount of dissolved oxygen in the water. Due to their much superior purity compared to the chemically synthesized counterparts and their photoluminescence response, the nanoparticles present the possibility for biological in vivo applications such as drug vectoring, imaging, and therapeutics

Nanocomposites based on plasmonic nanoparticles and metal‐oxide semiconductors are emerging as promising materials for conversion of solar energy into chemical energy. In this work, a Au–ZnO nanocomposite film with notably enhanced photocatalytic activity is successfully prepared by a single‐step process. Both ZnO and Au nanoparticles are synthesized in situ during baking of the film spin‐coated from a solution of Zn(CH3COO)2 and HAuCl4. Furthermore, it is shown that this precursor solution can be formulated as a nanoink for the generation of micropatterns by microplotter printing, opening the way for the miniaturization of devices with enhanced properties for photocatalysis, optoelectronics, and sensing. The study demonstrates that Au–ZnO films exhibit 4.5‐fold enhanced photocatalytic properties for the decomposition of methyl orange upon sunlight exposure in comparison with ZnO films. Au nanoparticles improve significantly the photocatalytic activity of ZnO because they act as photosensitizers, absorbing photons at the localized surface plasmon resonance range (500–600 nm) and transferring electrons to the nearby ZnO semiconductor. XPS analysis of the Au–ZnO nanocomposite supports this explanation, indicating strong interactions between Au and ZnO.

We report an atmospheric-pressure deposition method for preparing well-adhered and compact CuInS 2 films. The precursor film is obtained by a solution-coating technique and is subjected to a low-cost and safe one-step reduction-sulfurization treatment. A maximum thickness of 300 nm is achieved per layer, and up to three layers were sulfurized at a time. The obtained films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and visiblenear-infrared (vis-NIR) spectrophotometry.

Innige Verbindung: Die Einwirkung von X2 (Cl2, Br2, I2) auf das poröse Spin‐Crossover‐Material {Fe(pz)[PtII(CN)4]} (pz=Pyrazin) führt durch oxidative Addition zum Halogenid‐Einbau in die koordinativ ungesättigten [PtII(CN)4]2−‐Einheiten. Eine Serie gemischtvalenter {Fe(pz)[PtII/IV(CN)4(X)]}‐Gerüste mit charakteristischem kooperativem Spinübergang wurde erhalten.

Nitrogen doped gallium selenide single crystals are studied through Hall effect and photoluminescence measurements in the temperature ranges from 150 to 700 K and from 30 to 45 K, respectively. The doping effect of nitrogen is established and room temperature resistivities as low as 20 ⍀ cm are measured. The temperature dependence of the hole concentration can be explained through a single acceptor-single donor model, the acceptor ionization energy being 210 meV, with a very low compensation rate. The high quality of nitrogen doped GaSe single crystals is confirmed by photoluminescence spectra exhibiting only exciton related peaks. Two phonon scattering mechanisms must be considered in order to give quantitative account of the temperature dependence of the hole mobility: scattering by 16.7 meV A 1 Ј homopolar optical phonons with a hole-phonon coupling constant g 2 ϭ0.115 and scattering by 31.5 meV LO polar phonon with a hole Fröhlich constant ␣ hЌ ϭ0.741.