Mixed Aerogels from Au and CdTe Nanoparticles

Abstract

Mixed metal–semiconductor nanocrystal aerogels are fabricated, which are light‐emitting and highly porous macroscopic monoliths. Thiol‐stabilized CdTe and Au nanoparticles from aqueous synthesis act as building blocks for the hybrid material. The Au colloids undergo a surface‐modification to enhance the particle stability and achieve thiol functionalities. A photochemical treatment is applied for the gelation process which is found to be reversible by subsequent addition of thiol molecules. Via supercritical drying aerogels are formed. The variation of the initial CdTe to Au nanoparticle ratio permits a facile tuning of the content and the properties of the resulting aerogels. The obtained structures were characterized by means of optical spectroscopy, electron microscopy, elemental analysis, and nitrogen physisorption.

In Situ Determination of Colloidal Gold Concentrations with UV–Vis Spectroscopy: Limitations and Perspectives

“…Water-soluble thiolatecapped GNPs were prepared upon addition of an aqueous solution of MSA to as-prepared GNP BH4 . 44,73 GNP in organic solvent were prepared by transferring GNP BH4 to DT in toluene via simple extraction (see Experimental Details for more information). The completeness of the phase transfer with DT was checked by measuring the UV-Vis spectrum of the corresponding water phase.…”

“…[37][38][39][40] From atomic spectroscopy such as atomic absorption spectroscopy (AAS) 23,41 or optical emission spectroscopy (OES) [42][43][44] elemental gold concentrations can be obtained. Typically, GNP solutions are dissolved in strong acids before analyzed.…”

“…However, UV-Vis spectra of GNPs with equal Au(0) concentration are normalized at 400 nm occasionally and in general without further explanation. 44,54,55,[58][59][60][61][62] It has to be noted that in these publications, the GNPs have different sizes, shapes and surface modifications. This paper evaluates the determination of the absolute Au(0) concentration in aqueous GNP solution applying the Abs 400 .…”

Self-doping and surface plasmon modification induced visible light photocatalysis of BiOCl

“…For the AB5 sample, the values of s 1 and s 2 are 0.17 and 2.40 ns, respectively, giving a lower hsi value of 0.37 ns. 62 According to Mott-Schottky plots (Fig. 7) and photocurrent (Fig.…”

Anordnung von BaTiO3‐Nanokristallen zu makroskopischen Aerogelmonolithen mit großer Oberfläche

“…Ungeachtet des erheblichen Aufwandes, dieses Konzept auf vorgefertigte nanokristalline Bausteine anderer Materialien zu erweitern, blieb die Zusammensetzung auf Metallchalkogenide, [9] Edelmetalle [10] und deren Kombination beschränkt. [11] Basierend auf der Beobachtung, dass die Destabilisierung von Oberflächen-funktionalisierten Titandioxidnanopartikeln zu orientierter Anlagerung in einer bevorzugten Richtung über mehrere Grçßenordnungen führt, [12] [15] Allerdings sind die wenigsten dieser Oxide geneigt, sich orientiert anzulagern, und sind daher schwierig zu gelieren.…”