Unit:
Department of PhysicsLibrary of the School of Science
Author:
Lambropoulos Konstantinos
Dissertation committee:
Κωνσταντίνος Σιμσερίδης (Επίκουρος Καθηγητής Τμήματος Φυσικής ΕΚΠΑ)
Βλάσιος Λυκοδήμος (Επίκουρος Καθηγητής Τμήματος Φυσικής ΕΚΠΑ)
Σπυρίδων Γαρδέλης (Αναπληρωτής Καθηγητής Τμήματος Φυσικής ΕΚΠΑ)
Νικόλαος Στεφάνου (Καθηγητής Τμήματος Φυσικής ΕΚΠΑ)
Φοίβος Μαυρόπουλος (Καθηγητής Τμήματος Φυσικής ΕΚΠΑ)
Rosa di Felice (Associate Professor, Department of Physics and Astronomy and Biological Sciences, University of Southern California, Los Angeles, USA)
Enrique Alfonso Macia Barber (Professor, Departamento de Física de Materiales, Universidad Complutense de Madrid, Spain)
Original Title:
Energy structure and charge transport-transfer in molecular wires: carbynes, and periodic, deterministic aperiodic and random DNA
Translated title:
Energy structure and charge transport-transfer in molecular wires: carbynes, and periodic, deterministic aperiodic and random DNA
Summary:
We theoretically study the energy structure and the charge transport and transfer properties of π-conjugated molecular wires, using variants of the Tight-Binding Method. Charge transport implies the use of leads and the application of external voltage. We start with an analytical and numerical study of the spectral and transmission properties of periodic Tight-Binding wires with a generic unit cell, focusing on the effect factors such as the strength and asymmetry of coupling between the leads an the system induce on the transmission profiles. Our method is then applied to the study of atomic carbon wires (or carbynes). Carbynes represent the ultimate nanoscale structure, having a thickness of just one carbon atom, and are promising for electronic applications. We show that Ohmic, semiconducting or rectifying behavior occurs, depending on the carbyne structure and the leads, and we reproduce experimental results regarding the current-voltage curves. We move on to an examination of the energy structure, localization and charge transport in periodic, deterministic aperiodic and random binary DNA sequences. The ability to produce nucleic acid sequences of interest provides the chance to create molecular wires with tailored properties. In our study, we focus on the interplay between the sequence structure and the aforementioned properties. Charge transfer means that an extra carrier (hole or electron), created or injected at a specific location, moves to more favorable locations. We focus on aspects of this phenomenon such as the frequency content of transfer, the mean over time probabilities to find the carrier at each site of a DNA segment, and the pure mean transfer rates. We start with small DNA segments (composed of one, two, and three base pairs). Our results are compared with the more complex, yet more computationally costly, Real-Time Time-Dependent Density Functional Theory. We move on to the study of several classes of periodic DNA segments (monomer-polymers, dimer-polymers, polymers with increasing repetition unit). Finally, we compare periodic DNA segments with deterministic aperiodic and random ones regarding charge transfer, and make some remarks regarding experimental charge transfer rates.
Main subject category:
Science
Keywords:
Charge transport, Charge transfer, DNA, carbynes, Tight-Binding Method
Number of references:
274
