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 20 of 51 for “"Charge carrier mobility"”.
-
Quantum dynamics in condensed phases : charge carrier mobility, decoherence, and excitation energy transfer
… processes in condensed phases. First, we study charge-carrier mobilities in organic molecular crystals, and develop a microscopic theory that describes both the coherent band-like and incoherent hopping transport observed in organic crystals. We investigate the structures of polaron states using …
-
Effect of Moiety Choice on Structural and Electrical Properties in Organic Semiconductors
… beginning with measurements of field-effect charge carrier mobility in order to evaluate the materials' relative electrical performance, followed by a variety of characterisation techniques of their photophysical properties in order to understand the reasons for differences observed in the …
-
Amorphous hydrogenated boron carbide for solid-state direct-conversion thermal neutron detection
… hindered by its poor and/or not well understood charge transport properties as well as fabrication challenges. This study focuses on obtaining thick and stable a-BC:H films using plasma-enhanced chemical vapor deposition (PECVD) and optimizing their charge transport properties for potential …
-
Improved Organic Semiconductor Thin-Film Formation through the Addition of Vibrations to the Solution Shearing Method
In this thesis, methods for improving charge carrier mobility and deposition conditions for the solution shearing of organic semiconductors for organic field-effect transistors (OFETs) are investigated. Electrical performance for OFETs is currently still limited by the charge carrier mobility, …
-
Design and optimization of colloidal quantum dot solids for enhanced charge transport and photovoltaics
… higher, a better understanding of the charge transport phenomena in CQD films is needed. While the carrier transport mechanisms between isolated molecules have been explored theoretically and the device-scale mobility of CQD layers has been characterized using experimental measurements …
-
Charge-carrier transport in amorphous organic semiconductors
… 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 than in their covalently-bonded, highly-ordered crystalline semiconductor counterparts. Indeed, one major …
-
Highly conductive sodium dodecyl sulphate treated poly (3,4-ethylendioxylthiophene) : polystyrene sulfonate (pedot: pss) containing copper nanoparticles for flexible organic solar cells
… Scanning electron microscopy (SEM) and Raman. Charge carrier mobility was characterised using the Hall Effect Measurements. Conductivity measurements were done using a four-point probe coupled to a source meter. The conductivity of PEDOT: PSS films were significantly enhanced from 0.56 +0.19 …
-
Highly conductive sodium dodecyl sulphate treated poly (3,4-ethylendioxylthiophene) : polystyrene sulfonate (pedot: pss) containing copper nanoparticles for flexible organic solar cells
… Scanning electron microscopy (SEM) and Raman. Charge carrier mobility was characterised using the Hall Effect Measurements. Conductivity measurements were done using a four-point probe coupled to a source meter. The conductivity of PEDOT: PSS films were significantly enhanced from 0.56 +0.19 …
-
Fluorescence Enhancement Strategies for Polymer Semiconductors
… rules and processing routes which optimise the charge carrier mobility, whilst independently controlling the radiative and non-radiative processes. To date there has existed a seeming trade-off between charge carrier mobility and photoluminescence efficiency, which limits the development of some …
-
Thiophene Based Semiconductors: Synthesis and Characterizations
… for FET fabrication because of their good mobility and environmental stability. However, most of unsubstituted oligothiophenes are insoluble that suppresses their potential industrial utility. On the first stage of the work, conformation, crystalline structure, molecular packing and charge …
-
Chain-Growth Polymerization of 3-Hexylthiophene Towards Well-Defined Semiconductor Block Copolymers
… in solution seemed to indicate the resulting charge carrier mobility measured in organic thin film field effect transistors. For the well-defined P3HTs, even low molecular weight samples allow for high charge carrier mobility. In the third part the bromine end groups were used to introduce …
-
Understanding emergence of supramolecular chirality in lyotropic conjugated polymers
… chirality on device-relevant properties, such as charge carrier mobility and conductivity upon chemical doping. In Chapter 2, I explore the LC-mediated assemblies of conjugated polymers, uncovering a ubiquitous yet previously overlooked phenomenon: the spontaneous chiral emergence during the …
-
Contact-free Electrical Characterisation of Novel Materials Using Terahertz Spectroscopy
… a remarkable, long-term improvement in the charge carrier lifetime and charge carrier dynamics was demonstrated while retaining the charge carrier mobility. In addition, a demonstrated three-fold order of magnitude decrease in the surface recombination velocity was achieved by the ultra-thin …
-
Alkynylated acenothiadiazoles and N-heteroacenes: synthesis, functionalization, and study of the optical properties for optoelectronic and sensory materials
… materials are needed which display good charge carrier mobility, good processability, and stability towards oxygen and moisture. Alkynylated N-Heteroacenes fulfill many of these requirements. Substitution with alkyne groups as well as the introduction of the pyrazine subunit both inhibits …
-
Nematic liquid crystals for nano-structured organic photovoltaic
… acceptors.Time-of-flight was used to study the charge transport of organic semiconductors in this thesis. The nature of the functional groups of the molecules was found to have a significant influence on the charge carrier mobility. The incorporation of a reactive end group with spacer affected …
-
Temperature effects on the electronic properties of lead telluride (PbTe) and the influence of nano-size precipitates on the performance of thermoelectric materials. (SrTe precipitates in PbTe bulk material)
… Using the electronic properties attained, the charge carrier scattering relaxation times were determined. The effect of interface between PbTe and SrTe on the charge carrier mobility was studied by finding out the relative alignment of energy bands at the semiconductor heterojunction. The …
-
Studies on structural, electronic and optical properties of SnO2 doped with nitrogen, chloeine, antimony and indium
… However, the photocatalytic activity and charge carrier mobility are constrained by the large band gap. A cost-effective and efficient method for reducing the SnO2 band gap and increasing the potential for photocatalytic applications is doping with different elements. Examining how …
-
Molecular design for controlling morphology in organic electronics
… a correlation between molecular packing and charge carrier mobility. Chapter 4 discusses strategies to enhance conjugation in organic electronic materials, using 2,5-di(thiophenyl)-N-arylpyrrole (SNS) as a model system. The first section describes synthetic routes to access a novel polycyclic …
-
Morphology, charge transport properties, and molecular doping of thiophene-based organic semiconducting thin films
… thesis concentrates on understanding how the charge transport in thiophene-based semiconductor layers depends on the layer morphology and how the charge transport properties can be intentionally modified by doping these layers with a strong electron acceptor. By means of optical spectroscopy, …
-
Elementary processes in layers of electron transporting Donor-acceptor copolymers : investigation of charge transport and application to organic solar cells
… inorganic semiconductors. Most impressively, the charge carrier mobility of D-A copolymers has been pushed to the technologically important value of 10 cm^{2}V^{-1}s^{-1}. Furthermore, owed to their enormous variability they are the material of choice for the donor component in organic solar …
Page 1 of 3