Events Calendar

NEXT 10 EVENTS ON OR AFTER March 3, 2015

[Show all events in March]

Thursday, March 5, 2015

2:00 PM - 3:00 PM

ANSER Center Seminar - Dr. Justin Johnson of NREL

Dr. Justin Johnson, of NREL, will deliver an ANSER seminar entitled, "Charge Carrier Generation and Transport in Surface-Modified Quantum Dot Films" on 3/5.

 

Abstract:

Quantum dots (QD) exhibit unique and interesting photophysical phenomena that have been well characterized over the past two decades. Utilization of these phenomena in optoelectronic devices incorporating QDs relies upon leveraging the potential ease and low cost of large scale fabrication with the promise of superior performance over bulk materials. In particular, photovoltaic (PV) devices require transfer of energy or charge over large length scales, involving many QD-QD interactions. In order to understand these interactions, we have employed spectroscopic probes of excitons and charges for investigating QD coupling regimes ranging from essentially isolated to strongly coupled by adjusting the matrix or “bridge” that exists between proximate QDs. Ultrafast transient spectroscopic techniques provide a “snapshot” of the nature of photogenerated excitons in different QD coupling environments, whereas probes on a picosecond to nanosecond timescale characterize the processes of exciton migration, charge separation, and nonradiative decay. On even longer time scales, low power and continuous-wave photoluminescence (PL) data enable the most direct connection between measured dynamics and real-world operation. Our findings indicate that the distribution between excitons and charge carriers can be measured by temperature dependent PL and controlled with ligand modifications. Moreover, not only charge separation but also charge carrier mobilities can be inferred from PL data collected with no potential bias. Fast nonradiative decay channels, which are the primary hurdle to optimal device performance, can be reduced significantly with a synthetic and post-synthetic scheme of hybrid organic/inorganic surface passivation that renders the QD films similar to successful bulk semiconductors in terms of key photovoltaic characteristics. The results of spectroscopic measurements are harmonious with trends in field-effect transistor and PV devices, such as significant bimolecular radiative decay under open circuit. Theoretical justification for the strong influence of surface chemistry on such properties is being developed.

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Justin Johnson of NREL

Dr. Justin Johnson, of NREL, will deliver an ANSER seminar entitled, "Charge Carrier Generation and Transport in Surface-Modified Quantum Dot Films" on 3/5.

 

Abstract:

Quantum dots (QD) exhibit unique and interesting photophysical phenomena that have been well characterized over the past two decades. Utilization of these phenomena in optoelectronic devices incorporating QDs relies upon leveraging the potential ease and low cost of large scale fabrication with the promise of superior performance over bulk materials. In particular, photovoltaic (PV) devices require transfer of energy or charge over large length scales, involving many QD-QD interactions. In order to understand these interactions, we have employed spectroscopic probes of excitons and charges for investigating QD coupling regimes ranging from essentially isolated to strongly coupled by adjusting the matrix or “bridge” that exists between proximate QDs. Ultrafast transient spectroscopic techniques provide a “snapshot” of the nature of photogenerated excitons in different QD coupling environments, whereas probes on a picosecond to nanosecond timescale characterize the processes of exciton migration, charge separation, and nonradiative decay. On even longer time scales, low power and continuous-wave photoluminescence (PL) data enable the most direct connection between measured dynamics and real-world operation. Our findings indicate that the distribution between excitons and charge carriers can be measured by temperature dependent PL and controlled with ligand modifications. Moreover, not only charge separation but also charge carrier mobilities can be inferred from PL data collected with no potential bias. Fast nonradiative decay channels, which are the primary hurdle to optimal device performance, can be reduced significantly with a synthetic and post-synthetic scheme of hybrid organic/inorganic surface passivation that renders the QD films similar to successful bulk semiconductors in terms of key photovoltaic characteristics. The results of spectroscopic measurements are harmonious with trends in field-effect transistor and PV devices, such as significant bimolecular radiative decay under open circuit. Theoretical justification for the strong influence of surface chemistry on such properties is being developed.

Thursday, April 2, 2015

2:00 PM - 3:00 PM

ANSER Center Seminar - Dr. Tanja Cuk of UC Berkeley

Dr. Tanja Cuk, of the Chemistry department at UC Berkeley, will deliver an ANSER seminar on 3/5.

 

Abstract:

TBD

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Tanja Cuk of UC Berkeley

Dr. Tanja Cuk, of the Chemistry department at UC Berkeley, will deliver an ANSER seminar on 3/5.

 

Abstract:

TBD

Monday, April 20, 2015

3:00 PM - 4:00 PM

ANSER Center Seminar - Dr. Gordana Dukovic of the University of Colorado Boulder

Dr. Gordana Dukovic, of the University of Colorado Boulder, will deliver a special ANSER seminar on 4/20 from 3-4pm in Ryan 4003.

 

Abstract:

TBD

 

 

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Gordana Dukovic of the University of Colorado Boulder

Dr. Gordana Dukovic, of the University of Colorado Boulder, will deliver a special ANSER seminar on 4/20 from 3-4pm in Ryan 4003.

 

Abstract:

TBD

 

 

Thursday, September 3, 2015

2:00 PM - 3:00 PM

ANSER Center Seminar - Dr. Rachel Segalman of UC Santa Barbara

Dr. Rachel Segalman, of the Chemical Engineering Department department at UC Santa Barbara, will deliver an ANSER seminar on 9/3.

 

Abstract:

TBD

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Rachel Segalman of UC Santa Barbara

Dr. Rachel Segalman, of the Chemical Engineering Department department at UC Santa Barbara, will deliver an ANSER seminar on 9/3.

 

Abstract:

TBD

Thursday, October 1, 2015

2:00 PM - 3:00 PM

ANSER Center Seminar - Dr. Luis Campos of Columbia University

Dr. Luis Campos, of the Chemistry Department at Columbia University, will deliver an ANSER seminar on 10/1.

 

Abstract:

TBD

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Luis Campos of Columbia University

Dr. Luis Campos, of the Chemistry Department at Columbia University, will deliver an ANSER seminar on 10/1.

 

Abstract:

TBD

Thursday, November 5, 2015

2:00 PM - 3:00 PM

ANSER Center Seminar - Dr. Aaron Appel of PNNL

Dr. Aaron Appel, of PNNL, will deliver an ANSER seminar on 11/5.

 

Abstract:

TBD

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Aaron Appel of PNNL

Dr. Aaron Appel, of PNNL, will deliver an ANSER seminar on 11/5.

 

Abstract:

TBD

Thursday, December 3, 2015

2:00 PM - 3:00 PM

ANSER Center Seminar - Dr. Yogi Surendranath of MIT

Dr. Yogi Surendranath, of the Chemistry Department at MIT, will deliver an ANSER seminar on 12/3.

 

Abstract:

TBD

Contact Info: Ria Hirsch

Location: Ryan Hall 2190 Campus Drive Ryan 4003 Evanston, IL 60208

ANSER Center Seminar - Dr. Yogi Surendranath of MIT

Dr. Yogi Surendranath, of the Chemistry Department at MIT, will deliver an ANSER seminar on 12/3.

 

Abstract:

TBD

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