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1 nm CuO quantum dots (QDs) were produced in size-controlled super-micropores of a silica matrix. The reversible color change of the QDs from pale blue to deep green was clearly observed in a wide temperature range from 298 to 673 K. This particular thermochromism is ascribed to an enhanced bandgap shift depending on temperature with a strong electron–phonon coupling in the confined space of the 1 nm QDs.

A dot matrix: 1 nm CuO quantum dots have been prepared in microporous silica. They exhibit unique and reversible color change from pale blue to deep green in a wide temperature range from 298 to 673 K. This thermochromism is ascribed to an enhanced bandgap shift that depends on temperature, with a strong electron–phonon coupling in the confined space of the 1 nm CuO quantum dots.

New developments in the field of nanomaterials drive the need for quantitative characterization techniques that yield information down to the atomic scale. In this Review, we focus on the three-dimensional investigations of metal nanoparticles and their assemblies by electron tomography. This technique has become a versatile tool to understand the connection between the properties and structure or composition of nanomaterials. The different steps of an electron tomography experiment are discussed and we show how quantitative three-dimensional information can be obtained even at the atomic scale.

A sight for small eyes: In 3D investigations of metal nanoparticles and their assemblies, electron tomography has become a versatile tool to understand the connection between the properties and structure or composition of nanomaterials. The different steps of an electron tomography experiment are discussed and how quantitative 3D information can be obtained even at the atomic scale is shown.

The electronic phase behavior and functionality of interfaces and surfaces in complex materials are strongly correlated to chemical composition profiles, stoichiometry and intermixing. Here a novel analysis scheme for resonant X-ray reflectivity maps is introduced to determine such profiles, which is element specific and non-destructive, and which exhibits atomic-layer resolution and a probing depth of hundreds of nanometers.

Down to the last detail: Nanostructured solid catalysts were already known in the early 20th century, but their exact structure was unclear. Nowadays, the arrangement of atoms and particles in solids can be manipulated and analyzed down to the atomic scale (see image). The use of specific highly active catalysts enables industrially relevant reactions to be performed at room temperature.

N. López, J. Pérez-Ramírez, and co-workers show on page 8628 ff. that HBr doping of the rutile TiO₂ surface generates impurity levels with electrons that can be injected into or recovered from the reactants at the right energies, transforming the catalytically inert semiconductor into an active catalyst.

A reversible 2H-to-1T phase transition in a MoS₂ monolayer is realized by plasmonic hot electrons. This transition can be actively controlled by the incident light intensity, wavelength, sample areas, and perimeters, resulting in an effective shift of photoluminescence. The suggested configuration paves the way for plasmonic optoelectronic device applications of MoS₂ in the future.

Three organic or hybrid photovoltaic technologies are compared with respect to performance and stability under the harsh regime of concentrated light. Although all three technologies show surprisingly high (and linear) photocurrents, and better than expected stability, no golden apples are awarded.

Nanoconstructs are realized by P. Decuzzi and co-workers by confining ultra-small (5 nm) superparamagnetic iron oxide nanoparticles (USPIOs) within two different mesoporous structures (silicon and polymers). On page 4584, they exhibit transversal relaxivities up to around 10 times higher than conventional USPIOs and, under external magnetic fields, collectively cooperate to amplify tumor accumulation in mice to provide an MRI contrast enhancement at much smaller doses of iron as compared to current practice.