Replacing a single atom of a host semiconductor nanocrystal with a functional dopant can introduce completely new properties potentially valuable for "solotronic" information-processing applications. Here, we report successful doping of colloidal CdSe quantum dots with a very small number of manganese ions-down to the ultimate limit of one. Single-particle spectroscopy reveals spectral fingerprints of the spin-spin interactions between individual dopants and quantum-dot excitons. Spectrally well-resolved emission peaks are observed that can be related to the discrete spin projections of individual Mn ions. In agreement with theoretical predictions, the exchange splittings are enhanced by more than an order of magnitude in these quantum dots compared to their epitaxial counterparts, opening a path for solotronic applications at elevated temperatures.

Laser fragmentation of colloidal submicron-sized bismuth ferrite particles was performed by irradiating a liquid jet to synthesize bismuth ferrite nanoparticles. This treatment achieved a size reduction from 450 nm to below 10 nm. A circular and an elliptical fluid jet were compared to control the energy distribution within the fluid jet and thereby the product size distribution and educt decomposition. The resulting colloids were analysed via UV-VIS, XRD and TEM. All methods were used to gain information on size distribution, material morphology and composition. It was found that using an elliptical liquid jet during the laser fragmentation leads to a slightly smaller and narrower size distribution of the resulting product compared to the circular jet.

Commercial diesel oxidation catalysis mainly uses monometallic and bimetallic PtÀ Pd-based catalysts, but alloying with different elements has rarely been done systematically under industrial testing conditions. 45 binary alloys made of platinum and a selected 1 st and 2 nd -row transition metal, platinum group element, or coin metal were synthesized via a scalable laser synthesis method. Then, catalytic performance and durability were evaluated for one diesel oxidation and two ammonia-slip environments. The results show the highest activity when the adsorption enthalpy of molecular oxygen of the alloy was similar to the value of Pt. Furthermore, the durability of the alloy catalysts was found to increase with the melting point of the 2 nd element Pt was alloyed with, even at molar fractions. Our results further indicate beneficial synergies beyond the binary systems underlining the possibility of further improvements by considering ternary or multinary alloys, which are accessible via laser synthesis.