Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

You searched for +publisher:"University of North Carolina" +contributor:("Li, Lesheng"). One record found.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


University of North Carolina

1. Li, Lesheng. QUANTUM DYNAMICS OF EXCITED CHARGE CARRIER AT HETEROGENEOUS INTERFACE BETWEEN SEMICONDUCTOR AND ORGANIC MOLECULE.

Degree: Chemistry, 2018, University of North Carolina

Developing a quantitative understanding of excited charge carrier dynamics at heterogeneous interfaces between semiconductor and organic molecules is of great practical importance in advanced technologically important applications. Despite great advances in this field, there remain many aspects that are yet to be understood such as the density of charge carrier, the role of defects, and the interactions with surface ligand. To this end, we aim to develop and apply a quantitative formulation based on first-principles quantum theory to elucidate how excited carrier dynamics at semiconductor-molecule interfaces depend on the atomistic details. In this work, we systematically investigated several aspects of excited carrier dynamics at semiconductor-molecule interfaces via first-principles quantum mechanics simulations that are synergistically combined with the fewest-switches surface hopping algorithm, G0W0 many-body perturbation theory calculations, and first-principles molecular dynamics. We conclude that hot electron transfer to chemisorbed molecules was observed but was short-lived on the molecules. Interfacial electron transfer was found to be largely decoupled from hot electron relaxation within the semiconductor. While hot electron relaxation was found to take place on a time scale of several hundred femtoseconds, the subsequent interfacial electron transfer was slower by an order of magnitude. Meanwhile, this secondary process of picosecond electron transfer was found to be comparable in time scale to typical electron trapping into defect states in the energy gap. We then investigated how molecular details such as surface coverage and adsorbate species influence hot electron transfer. Counterintuitively, increasing surface coverage was found to suppress hot electron transfer probability because the increased delocalization of the hot electron accepting molecular states change the nonadiabatic couplings at the interface. In addition, the adsorbate species itself is an important factor in hot electron transfer not simply because of energy level alignments, but because the transfer is quite sensitive to nonadiabatic couplings. Finally, we examined the extent to which exchange-correlation approximations influence the interfacial charge transfer at a representative heterogeneous interface. We showed how the charge transfer kinetics are influenced by the exchange-correlation approximation through lattice movement, nonadiabatic couplings, and energy level alignments. The interfacial electron transfer time scale was found to vary by as much as, but not more than, one order of magnitude. Advisors/Committee Members: Li, Lesheng, Kanai, Yosuke, Cahoon, James, Berkowitz, Max, Atkin, Joanna, Dempsey, Jillian.

Subjects/Keywords: College of Arts and Sciences; Department of Chemistry

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Li, L. (2018). QUANTUM DYNAMICS OF EXCITED CHARGE CARRIER AT HETEROGENEOUS INTERFACE BETWEEN SEMICONDUCTOR AND ORGANIC MOLECULE. (Thesis). University of North Carolina. Retrieved from https://cdr.lib.unc.edu/record/uuid:d5f872cd-075e-4b36-8ff0-8f7d8b03fa6f

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Li, Lesheng. “QUANTUM DYNAMICS OF EXCITED CHARGE CARRIER AT HETEROGENEOUS INTERFACE BETWEEN SEMICONDUCTOR AND ORGANIC MOLECULE.” 2018. Thesis, University of North Carolina. Accessed November 25, 2020. https://cdr.lib.unc.edu/record/uuid:d5f872cd-075e-4b36-8ff0-8f7d8b03fa6f.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Li, Lesheng. “QUANTUM DYNAMICS OF EXCITED CHARGE CARRIER AT HETEROGENEOUS INTERFACE BETWEEN SEMICONDUCTOR AND ORGANIC MOLECULE.” 2018. Web. 25 Nov 2020.

Vancouver:

Li L. QUANTUM DYNAMICS OF EXCITED CHARGE CARRIER AT HETEROGENEOUS INTERFACE BETWEEN SEMICONDUCTOR AND ORGANIC MOLECULE. [Internet] [Thesis]. University of North Carolina; 2018. [cited 2020 Nov 25]. Available from: https://cdr.lib.unc.edu/record/uuid:d5f872cd-075e-4b36-8ff0-8f7d8b03fa6f.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Li L. QUANTUM DYNAMICS OF EXCITED CHARGE CARRIER AT HETEROGENEOUS INTERFACE BETWEEN SEMICONDUCTOR AND ORGANIC MOLECULE. [Thesis]. University of North Carolina; 2018. Available from: https://cdr.lib.unc.edu/record/uuid:d5f872cd-075e-4b36-8ff0-8f7d8b03fa6f

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.