Capacitively and Inductively Coupled Excitons in Bilayer MoS_{2}.

The coupling of intralayer A and B excitons and interlayer excitons (IE) is studied in a two-dimensional semiconductor, homobilayer MoS_{2}. It is shown that the measured optical susceptibility reveals both the magnitude and the phase of the coupling constants. The IE and B excitons couple via a 0-phase (capacitive) coupling; the IE and A excitons couple via a π-phase (inductive) coupling.

Dominant role of OH and Ti defects on the electronic structure of TiO thin films for water splitting.

Anatase/rutile constituting TiO thin films were prepared by sputter deposition, and the influence of the post-annealing step with a narrow window at 200 °C revealed a gaining factor of 5 in H production. An in-depth analysis of the photocatalytic performance revealed the dominant role of intermediate states rather than the heterocrystalline nature and the mesoscale structure. Structural, chemical and optical investigations based on scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-visible spectroscopy and photoluminescence supported by calculation correlated the H production with the dual presence of OH and Ti defects in the form of titanium interstitial atoms.

Mitigation of Edge and Surface States Effects in Two-Dimensional WS for Photocatalytic H Generation.

Large scale development of the 2D transition metal di-chalcogenides (TMDC) relies on landmark improvement in performance, which could emerge from nanostructuration. Using p-WS nanoflakes with different degrees of exfoliation and fracturing, perspectives were provided to develop high-surface-area 2D p-WS films for the photocatalytic hydrogen generation. The critical role of inter-nanoflakes contacts within high-surface-area 2D films was demonstrated, highlighting the benefit of plane/plane versus edge/plane contacts.

Interlayer exciton mediated second harmonic generation in bilayer MoS.

Second-harmonic generation (SHG) is a non-linear optical process, where two photons coherently combine into one photon of twice their energy. Efficient SHG occurs for crystals with broken inversion symmetry, such as transition metal dichalcogenide monolayers. Here we show tuning of non-linear optical processes in an inversion symmetric crystal.

Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field.

The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to 35% at zero applied magnetic field. The injection of spin-polarized electrons is achieved by combining ultrathin CoFeB electrodes on top of a spin-LED device with p-type InGaAs quantum dots in the active region.

Chemical insights into the formation of CuZnSnS films from all-aqueous dispersions for low-cost solar cells.

CuZnSnS (CZTS) shows great potential for photovoltaic application because of its non-toxic earth-abundant components and good optoelectronic properties. Combining low-cost and environmentally friendly routes would be the most favorable approach for the development of CZTS solar cells. In this context, development of CuZnSnS (CZTS) films from all-aqueous CZTS nanocrystals inks represents an interesting challenge.

Theoretical and experimental studies of (In,Ga)As/GaP quantum dots.

(In,Ga)As/GaP(001) quantum dots (QDs) are grown by molecular beam epitaxy and studied both theoretically and experimentally. The electronic band structure is simulated using a combination of k·p and tight-binding models. These calculations predict an indirect to direct crossover with the In content and the size of the QDs.