Sökning: "exciton theory"
Visar resultat 6 - 10 av 20 avhandlingar innehållade orden exciton theory.
6. Atomic Scale Modelling in Photoelectrocatalysis : Towards the Development of Efficient Materials for Solar Fuel Production
Sammanfattning : Using sunlight to produce valuable chemicals has been pointed out as an interesting alternative to deal with the well-known environmental problem related to the use of fossil fuels for energy generation. Thus, it is crucial for this field the development of novel photocatalysts that could drive the uphill reactions with high efficiency while presenting low price and toxicity. LÄS MER
7. Electrical and Optical Properties of AlGaAs/GaAs Aperiodic Superlattices and Resonant Tunneling Diodes. Theory, Design and Applications
Sammanfattning : The objective of the work presented in this thesis is to study quantum transport and optical properties of aperiodic superlattices and resonant tunneling diodes using III-V semiconductor heterostructures grown by molecular beam epitaxy. The study follows a procedure of theoretical modeling, computer-aided design and simulation, sample growth, and measurements. LÄS MER
8. Microscopic Theory of Charge Complexes in Atomically-Thin Materials
Sammanfattning : Atomically-thin materials have emerged as the most promising two-dimensional platform for future optoelectronic applications and for the study of quantum many-body physics. In particular, transition metal dichalcogenides (TMDs) exhibit strong Coulomb interaction, resulting in the formation of tightly-bound electron-hole complexes that dominate optics, dynamics, and transport. LÄS MER
9. Formation and Dynamics of Molecular Excitons and their Fingerprints in Nonlinear Optical Spectroscopy
Sammanfattning : An efficient transfer of energy in molecular systems has proven to be of fundamental importance both in nature and industrial applications. The ability of molecules to work together forming collective excitations, so-called excitons, plays a key role in for example the extraordinary fast energy transfer involved in the first steps of photosynthesis. LÄS MER
10. Electron-Lattice Dynamics in pi-Conjugated Systems
Sammanfattning : In this thesis we explore in particular the dynamics of a special type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is intimately related to the strong interactions between the electronic and the vibrational degrees of freedom within these systems. In order to conduct such studies with the particular focus of each appended paper, we simultaneously solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. LÄS MER