相关论文: Exciton character in picene molecular solids
We investigate the quenching of the photoluminescence (PL) from the divacancy defect in 4H-SiC consisting of a nearest-neighbour silicon and carbon vacancies. The quenching occurs only when the PL is excited below certain photon energies…
A theory of optical excitations by using a tight binding model with long-range Coulomb interactions is developed. The model is applied to a C60 molecule and a cluster, and is treated by the Hartree-Fock approximation followed by a…
The high surface sensitivity and controlled surface charge state of submicron sized droplets is exploited to study low-energy electron transport through liquid interfaces using photoelectron imaging. Already a few charges on a droplet are…
Precise understanding of the electronic structures of optically dark triplet-triplet multiexcitons that are the intermediate states in singlet fission (SF) continues to be a challenge. This is particularly true for intramolecular singlet…
The ultrathin transition metal dichalcogenides (TMDs) have emerged as promising materials for various applications using two dimensional (2D) semiconductors. They have attracted increasing attention due to their unique optical properties…
Excitons govern the light-matter interaction in 2D gapped materials with intrinsically large binding energies. In spite of plentiful optical measurements in the visible for semiconducting transition-metal dichalcogenides, we still lack…
Coupling molecular transition dipole moments to surface-plasmon polaritons (SPPs) results in the formation of new optical quasiparticles, i.e., plexcitons. Mixing the specific properties of matter excitations and light modes has proven to…
It is well-known that exciton effects are determinant to understand the optical absorption spectrum of low-dimensional materials. However, the role of excitons in nonlinear optical responses has been much less investigated at an…
The macroscopic exciton rings observed in the photoluminescence (PL) patterns of excitons in coupled quantum wells (CQWs) are explained by a series of experiments and a theory based on the idea of carrier imbalance, transport and…
We report on the principle and realization of an excitonic device: a ramp that directs the transport of indirect excitons down a potential energy gradient created by a perforated electrode at constant voltage. The device provides an…
Electron transfer to an individual quantum dot promotes the formation of charged excitons with enhanced recombination pathways and reduced lifetimes. Excitons with only one or two extra charges have been observed and exploited for very…
A study of the formation of excitons as a problem of two Dirac particles in a gapped graphene layer and in two gapped graphene layers separated by a dielectric is presented. In the low energy limit the separation of the center-of-mass and…
The attraction between electrons and holes in semiconductors forms excitons, which largely determine the optical properties of the hosting material, and hence the device performance, especially for low-dimensional systems. Mono- and…
First-order perturbation theory and many-body Green function analysis are used to quantify the influence of size, surface reconstruction and surface treatment on exciton transport between small silicon quantum dots. Competing radiative…
Two-dimensional perovskites, in which inorganic layers are stabilized by organic spacer molecules, are attracting increasing attention as a more robust analogue to the conventional three-dimensional metal-halide perovskites. However,…
We investigated excitation spectra of the one-dimensional chain compound Sr$_{2}$CuO$_{3}$. The small peak at 2.3 eV in the loss function was turned to correspond to the strong charge transfer transition at 1.8 eV in conductivity. It has…
We use a combination of dynamical mean-field model calculations and LDA+U material specific calculations to investigate the low temperature phase transition in the compounds from the (Pr$_{1-y}$R$_y$)$_x$Ca$_{1-x}$CoO$_3$ (R=Nd, Sm, Eu, Gd,…
The exciton Wannier equation for graphene is solved for different background dielectric constants. It is shown that freestanding graphene features strong Coulomb effects with a very large exciton binding energy exceeding $3\,$eV. A…
Controlling interlayer excitons in van der Waals heterostructures holds promise for exploring Bose-Einstein condensates and developing novel optoelectronic applications, such as excitonic integrated circuits. Despite intensive studies,…
While exciton relaxation in transition metal dichalcogenides (TMDs) has been intensively studied, spatial exciton propagation has received only little attention - in spite of being a key process for optoelectronics and having already shown…