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Physics

 


Seminars

Fall 2014 Seminars

Date

Title

Author

September 1, 2014

Labour Day

September 8, 2014

September 15, 2014

September 22, 2014

September 26, 2014

**Special time 3:00 - 4:00**Ab initio electron dynamics at metal–semiconductor nano-interfaces

Dmitri Kilin

September 29, 2014

October 6, 2014

October 13, 2014

TBA

Nathaniel Grosz

October 20, 2014

TBA

Kyung-Suk Kim

October 27, 2014

TBA

Alistair McInerny

November 3, 2014

Warren Christensen

November 7, 2014

TBA

Tereza Souza

November 10, 2014

TBA

Alfred Fahr

November 17, 2014

TBA

Matt Semmler

November 24, 2014

TBA

Alan Denton

December 1, 2014

TBA

Thomas Ihle

December 8, 2014

TBA

Andrew B. Croll

December 15, 2014

<Exam Week!> Elasticity-based mechanism for collective motion in natural and artificial swarms

Critian Huepe Minoletti

 

 

Ab initio electron dynamics at metal–semiconductor nano-interfaces.

Dr. Dmitri Kilin

Assistant Professor of Chemistry, University of South Dakota
 

FRIDAY, September 26, 2014, 3:00-4:00pm (Refreshments will be served at 2:30).

221 South Engineering

Photo-induced charge transfer at the interface of two materials is a fundamental process in (i) photovoltaic and (ii) photocatalytic applications. The photo-induced time-dependent electron dynamics are computed for different interfaces by a combination of ab initio electronic structure and time-dependent density matrix methodology. A dissipative equation of motion for the reduced density matrix for electronic degrees of freedom is used to study the phonon-induced relaxation of hot electrons in the simulated systems. Non-adiabatic couplings between electronic orbitals are computed on-the-fly along nuclear trajectories. Equations are solved in a basis set of orbitals generated ab initio from a density functional.[1] For an application to photovoltaic effect, one explores light-induced electric current in a model of a simplified photovoltaic cell composed of a Si nano-crystal co-doped with p-and n- type doping, interfacing with Au electrodes. Charge carrier dynamics induced by selected photo-excitations show that hole relaxation in energy and in space is much faster than electron relaxation. Use of the continuity equation for electric current allows to identify substantial local currents at the Si/Au interfaces and small overall net charge transfer across the slab. [2] For an application to photocatalytic water splitting, charge transfer dynamics is explored at the interface of supported metal nanocluster and liquid water. The metal cluster introduces new states into the band gap of semiconductor TiO2 surface, narrows the band gap of TiO2, and enhances the absorption strength. The H2O adsorption significantly enhances the intensity of photon absorption, which is due to the formation of metal−oxygen (water) coordination bonds at the interfaces. The metal cluster promotes the dissociation of water, facilitates charge transfer, and increases the relaxation rates of holes and electrons. [3] Reported results help in understanding basic photophysical and protochemical processes contributing to harvesting solar energy by photovoltaics and photoelectrochemical water splitting.

1. Huang, S.; Kilin, D. S., Charge Transfer, Luminescence, and Phonon Bottleneck in TiO2 Nanowires Computed by Eigenvectors of Liouville Superoperator. J. Chem. Theor. Computation 2014, 10 (9), 3996-4005.

2. Han, Y.; Micha, D.; Kilin, D., Ab initio study of the photocurrent at the Au/Si metal semiconductor nano-interface. Mol. Phys. 2014, in print, DOI: 10.1080/00268976.2014.944598.

3. Huang, S.; Inerbaev, T. M.; Kilin, D. S., Excited state dynamics of Ru10 cluster interfacing anatase TiO2(101) surface and liquid water. J. Phys. Chem. Lett. 2014, 5, 2823–2829.

Spring 2015 Seminars

Date

Title

Author

January 12, 2015

January 19, 2015

Martin Luther King, Jr. Day

January 26, 2015

February 2, 2015

February 9, 2015

February16, 2015

<Presidents' Day> Engineering Persister-Specific Antibiotics with Synergistic Antimicrobial Functions

Gerard Wong

February 23, 2015

March 2, 2015

APS March Meeting

 

March 9, 2015

March 16, 2015

Spring Break!!

March 23, 2015

March 30, 2015

April 6, 2015

Spring Recess

April 13, 2015

April 20, 2015

TBA

Alfredo Alexander-Katz

April 27, 2015

May 4, 2015

TBA

Jessica Striker

May 11, 2015

Exam Week!

 

 


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Published by Department of Physics

Last Updated: Tuesday, September 23, 2014 4:57:00 PM