aWe investigate the temperature-dependent decay kinetics of type II CdSe-CdTe and CdTe-CdSe corelateral shell nanoplatelets. From a kinetic analysis of the photoluminescence (PL) decay and a measurement of the temperature dependent quantum yield we deduce the temperature dependence of the non-radiative and radiative lifetimes of hetero nanoplates. In line with the predictions of the giant oscillator strength effect in 2D we observe a strong increase of the radiative lifetime with temperature. This is attributed to an increase of the homogeneous transition linewidth with temperature. Comparing core only and hetero platelets we observe a significant prolongation of the radiative lifetime in type II platelets by two orders in magnitude while the quantum yield is barely affected. In a careful analysis of the PL decay transients we compare different recombination models, including electron hole pairs and exciton decay, being relevant for the applicability of those structures in photonic applications like solar cells or lasers. We conclude that the observed biexponential PL decay behavior in hetero platelets is predominately due to spatially indirect excitons being present at the hetero junction and not ionized e-h pair recombination.

Fluorescent proteins with a wide variety of physicochemical properties have evolved in the past few years. The use of these proteins for applications in biomolecular nanosciences requires their precise positioning at the nanometer length scale. To address this challenge, we report here on the self-organization of DNA-tagged fluorescent probes to construct a set of photofunctional supramolecular complexes which include the enhanced yellow fluorescent protein (EYFP). The optical functionality is based on the strongly distance dependent fluorescence resonance energy transfer (FRET), occurring between the donor (EYFP) and an acceptor fluorophore, i.e., the fluorescent dye Atto647. The photophysical properties of four bimolecular FRET complexes, each possessing a well-defined donor-acceptor distance defined by the length of the interconnecting DNA backbone, are investigated by two-dimensional photoluminescence excitation spectroscopy (2D-PLE).

No abstract

Semiconductor nanowires (NWs) have attracted much attention as light emitters at the nanoscale. Due to their unique optical properties, they can be functionalized to hybrid structures in connection with plasmonic nanostructures. CdSe colloidal nanorods (NRs) show a fine structure which is investigated at single NW level. Four types of individual NR spectra have been found and attributed to different neutral, charged and multiexciton states. Additionally, plasmons in single silver NWs have been investigated. Those metallic NWs allow us to study surface plasmon mediated interference phenomena in low-Q nanocavities. In a third step, metallic NW cavities are functionalized with semiconductor NWs to study excitonplasmon interaction. Exciton-plasmon-photon conversion and waveguiding can be seen in dependence on wire length and metal-semiconductor spacing in the investigated structure.

We analyze the lineshape of the quasiparticle photoluminescence of monolayer (ML) and bilayer (BL) molybdenum ditelluride in temperature-and excitation intensity-dependent experiments. We confirm the existence of a negatively charged trion in the BL based on its emission characteristics and find hints for a coexistence of intra-and interlayer trions with a few meV splitting in energy.From the lineshape analysis of exciton and trion emission we extract values for exciton and trion deformation potentials as well as acoustical and optical phonon-limited mobilities in MoTe 2 . We estimate an acoustical phonon limited mobility of 6000 and 4300 cm 2 Vs −1 for the exciton at low temperature for ML and BL, respectively, which corresponds to an electron mobility of 10 5 cm 2 Vs −1 . At higher temperatures, the optical phonons limit the mobility to 1100 and 250 cm 2 Vs −1 for ML and BL.