Femtosecond Time-Resolved Laser Spectroscopic Studies on the Electron Dynamics in Heterostructured Nanomaterials

My interest in the photoscience has been focused on the photoinduced charge carrier dynamics in heterostructured nanomaterials. Of particular interest are type-II heterostructures, where the relative band alignment of their constituent semiconductor materials promotes a spatial separation of the electron and hole following photoexcitation, a highly desirable property for photovoltaic applications. Femtosecond laser spectroscopy has been used to investigate charge transfer dynamics with a time resolution of 100 fs and better. Using femtosecond transient absorption and time-resolved photoluminescence spectroscopy, we have studied the electron versus the hole dynamics in quasi-type-II hetero-nanomaterials. By choosing the pump wavelength in resonance with the respective core and shell transitions, we were able to measure the excited electron and hole dynamics selectively. Both charge carriers transfer through the interface within one picosecond, but the subsequent relaxations of the electron and hole are very distinguishable. On the basis of our measurements and analysis from the steady-state spectra, we find that the mixed core - charge transfer states and the electron transfer occur in the Marcus inverted region. The electron transfer dynamics in organic macromolecular complexes are also of interest in this dissertation. The organic capsule named octa acid is the model system studied with femtosecond laser techniques. We believe that understanding the charge carrier dynamics in nano- and supramolecular systems will pave the way to emergent optoelectronic and photovoltaic applications based on the design of functional nanoarchitectures. Moreover, exploring novel combinations, which are earth-abundant and environmentally benign, will make photoactive nanomaterials more applicable for broader use. Heterostructured assemblies (organic and inorganic) are pivotal materials in this context.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

Case Western Reserve University School of Graduate Studies

Year dc:date

2013

Author dc:creator

• Chuang, Chi-Hung

Contributors dc:contributor

• Burda, Clemens

• Physical Chemistry
• Nanoscience
• Nanotechnology

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=case1364836776

OAI identifier oai:identifier

oai:etd.ohiolink.edu:case1364836776