This article deals with some recent developments in metal and in semiconducting nanocluster science. Our studies on the properties, mainly of metal nanoclusters, with respect to future and also to current applications are reviewed, including a series of unpublished results. The general properties of metal clusters of one up to a few nanometers

CdSe quantum dots (QDs) with a high fluorescence quantum yield of 25% and a narrow size distribution were synthesized in a single step in water using glutathione as a stabilizing molecule. The exceptional optical properties enabled for the first time the detection of in-water-prepared single quantum dots at room temperature. For application as fluorescent bioanalytical probes, the QDs were coated with streptavidin. These QDs self-assemble with high contrast on micropatterned biotin while preserving their optical properties and their capability to bind in addition biotinylated molecules, a prerequisite for the development of novel supramolecular structures and bioassays.

Simply dipping polyethyleneimine-modified surfaces into aqueous solutions of acid-functionalized Au(55) clusters generates two-dimensional hexagonal and cubic arrangements of the clusters. The picture shows the transmission electron micrograph of the cubic arrangement; the bar length corrsponds to 10 nm.

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Einfaches Tauchen Polyethylenimin‐modifizierter Oberflächen in wässrige Lösungen säurefunktionalisierter Au55‐Cluster liefert zweidimensionale hexagonale und kubische Anordnungen dieser Cluster. Das Bild zeigt die transmissionselektronenmikroskopische Aufnahme einer kubischen Anordnung; die Kantenlänge entspricht 10 nm.