Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 19 of 19 for “"Energetic Disorder"”.
-
Charge carrier dynamics in lead sulfide quantum dot solids
… quantum dot solids, the site-to-site energetic disorder that comes from size dispersity and the size-dependent band gap is very small and spatial disorder in the quantum dot superlattice often has a greater impact on charge transport. In Chapter 2, we show that improved structural …
-
Decoherence and Dephasing of Vibronic Excitons /
… spectrum, (ii) the effect of static energetic disorder on the coherences depends on the nature of the states involved in the quantum superposition, (iii) for vibronically-coupled systems, the lifetime of excitonic coherences are determined by the coupling to discrete modes of …
-
Vibroninių eksitonų išsifazavimas ir dekoherencija /
… spectrum, (ii) the effect of static energetic disorder on the coherences depends on the nature of the states involved in the quantum superposition, (iii) for vibronically-coupled systems, the lifetime of excitonic coherences are determined by the coupling to discrete modes of …
-
Charge transport and mechanical property study of high mobility conjugated polymers
… property of these materials to their energetic disorder. Charge transport property of these newly emerged materials is investigated by OFETs characterisation. An alignment setup is built to fully utilise the rigid backbone of these fused polymers, align polymer chains along a certain …
-
Seebeck coefficient in organic semiconductors
… can be used as a tool to quantify the role of energetic disorder in organic semiconductors. To this end, a microfabricated chip was designed to perform accurate measurements of the Seebeck coefficient within the channel of the active layer in a field-effect transistor (FET). When measured …
-
An investigation into vibrational dynamics in organic semiconductors
… in conjugated polymers is strongly affected by energetic disorder arising from spatial variations in backbone conformation. I combine vacuum phase DFT simulations of intramolecular vibrational modes with pressure-dependent Raman spectroscopy to study planarity and torsional backbone disorder of …
-
Controlling nanomaterial self-assembly for next generation optoelectronic applications
… in the ensemble of nanocrystals introduces energetic disorder and spatial disorder in films. While synthesized as a colloid, for most applications the nanocrystals are deposited as a thin film. The rate of energy transfer between nanocrystals in the film, dictated by the arrangement and …
-
Charge-carrier transport in amorphous organic semiconductors
… electronic bandwidths. Combined with spatial and energetic disorder due to weak intermolecular interactions, the small bandwidth leads to localization of charge carriers and electron-hole pairs, called excitons. Thus, the charge-carrier mobility in organic semiconductors is generally much smaller …
-
Charge and exciton dynamics in quantum dot light-emitting diodes
… short range Coulomb interactions, we find that energetic disorder of the QD film strongly enhances the formation of negatively charged excitons by increasing the population of two-electron occupied QDs. Finally, we demonstrate that the photoluminescence yield of a QD film can be intentionally …
-
Single atom imaging with time-resolved electron microscopy
… anomalous diffusion as a result of spatial and energetic disorder present in the substrate. The investigation is extended to examine the structure and stability of small Cu clusters on graphene oxide, with atomistic modelling used to understand the significant role played by the substrate. …
-
Performance limits for colloidal quantum dot and emerging thin-film solar cells
… in the face of inefficient charge extraction and energetic disorder. First, we introduce material complexity as a framework for analyzing PV technologies and assess the performance and scalability of all leading technologies on equal footing. This analysis points to a unique advantage of emerging …
-
Pigment-Pigment Interactions and Protein Dynamics in Light-Harvesting Complexes: a Single-Molecule Study
… estimate on the amount of random and correlated energetic disorder in the site energies of the chromophores as well as on structural properties of the complexes could be given. In experiments on individual LH2-LH1-RC complexes, the energy transfer within a single photosynthetic unit was observed. …
-
Exciton transport and coherence in molecular and nanostructured materials
… as molecules, polymers, and nanocrystals. These disordered materials have enabled devices such as organic light emitting diodes, color tunable lasers, and low-cost photovoltaics, and hold promise as a platform for all-optical computing. The defining optical and electronic characteristic of …
-
Transient Photophysics of Bismuth Halide Semiconductors for Optoelectronic Applications
… bismuth oxyiodide, BiOI, have a great degree of energetic disorder, most likely due to the presence of self-trapped excitons and defect states. Transient absorption measurements give an excited state lifetime of 47 ps, which would make efficient photovoltaic performance of BiOI thin film …
-
Improving the Stability of Organic Field-Effect Transistors
… (IDT-BT) as our model system due to its low energetic disorder and high reported mobilities exceeding 1 cm<sup>2</sup>V<sup>−1</sup>s<sup>−1</sup>. Since stability studies require an exceptional level of reproducibility, we investigated the influence of the fabrication conditions and polymer …
-
The Hall Effect for Probing Conjugated Polymer Charge Transport in High Carrier Density Regimes
… delocalisation of carriers, relative levels of energetic disorder as well as hopping dimensionality can all theoretically be determined. This is in addition to the traditional quantities typically extracted from Hall measurements: mobile charge carrier density and mobility. By performing these …
-
Enhancing Fluorescence and Charge Transport in Disordered Organic Semiconductors
… apparent trade-off between $\mu$ and $\Phi$ in disordered systems. Recent reports of state-of-the-art device performance often optimise $\mu$ and $\Phi$ in disordered organic materials separately, and employ multi-layer architectures. In this work, we investigate materials in a class of …
-
Molecular Encapsulation of Conjugated Polymers for Organic Electronics
… in polymers exhibiting a lower degree of energetic disorder and increased spacing between polymer chains. However, it is noteworthy that the photoluminescence quantum yield (PLQY) in the solid state is unexpectedly lower (1%) compared to previous studies. Nevertheless, when assessing the …
-
Analytical and numerical studies of photo-injected charge transport in molecularly-doped polymers
… analytical and numerical predictions of five disorder-based models, the Gaussian disorder model (GDM) of Bäassler, and four correlated disorder models introduced by Novikov, et al., and by Parris, et al. In these numerical studies, disorder parameters describing each model were varied from …