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Charge Generation in Organic or Perovskite Photovoltaics

报告题目:Charge Generation in Organic or Perovskite Photovoltaics

 

报告人: Xiaoyang Zhu 教授Columbia University

报告时间: 6月1日下午 2:30 -3:30

报告地点:907楼1101房间

 

This lecture will address physical mechanisms responsible for efficient charge carrier generation in organic donor/acceptor and hybrid lead halide perovskite based thin film solar cells. In the former, I will discuss the salient feature due to the poorly screened Coulomb potential that can give rise to bound electron-hole pairs across the interface, i.e., charge transfer (CT) excitons. I will emphasize the competition between localization and delocalization in ensuring efficient charge separation. For the recently emerging material of lead halide perovskites, I will point out the unique physical properties of these materials that give rise to their exceptional solar cell performance. These properties include, among others, the partial ionic nature with little charge carrier trapping and remarkable screening properties that are likely reasons for the exceptionally long carrier lifetimes and, hence, high solar-to-electric power conversion efficiency.

 

 

 

Xiaoyang Zhu教授简历

 

Department of Chemistry, Columbia University, e-mail: xz2324@columbia.edu

Professional Preparation                                                                           

Fudan University, Shanghai        Chemistry              B.S                  1984

University of Texas, Austin         Chemistry              Ph.D.               1989

University of Texas, Austin         Chemistry              Postdoc           1990-1992

Fritz-Haber-Institute, Berlin          Surface Science    Postdoc           1992-1993

Appointments

07/1993–06/1997     Assistant Professor of Chemistry, Southern Illinois Univ., Carbondale.

07/1997–06/2002     Associate Professor of Chemistry, University of Minnesota.

07/2002-06/2008      Professor of Chemistry, University of Minnesota

07/2008-06/2009      Merck Endowed Professor of Chemistry, University of Minnesota

10/2010-05/2012      Director, DOE Energy Frontier Research Center at UT Austin

07/2009-12/2012      L. N. Vauquelin Regents Professor of Chemistry, UT Austin

07/2009-12/2012      Director, Center for Materials Chemistry, UT Austin        

01/2013-present       Professor of Chemistry, Columbia University

 

Honors & Awards

Awards

Alexander-von-Humboldt Fellowship, Humboldt Foundation, 1992.

Camille and Henry Dreyfus New Faculty Award, Dreyfus Foundation, 1993.

Cottrell Scholar Award, Research Corporation, 1996.

Friedrich Wilhelm Bessel Award, Humboldt Foundation, 2006.

Fellow of the American Physical Society, 2011.

Other distinctions

Brian Bent Memorial Lecturer, Columbia University, 02/15/2007.

Plenary Lecturer, 31st DOE Solar Photochem. Meeting, Annapolis, MD, 06/07/2009.

Welch Lecturer, Welch Conference, Houston, TX, 10/ 25/2010

Milton Kahn Lecturer, University of New Mexico, Albuquerque, NM, 04/22/2011

Plenary/public lecturer, I-CAMP Summer School, Boulder, CO, 08/10/2012

Plenary lecturer, Southeast Ultrafast Conference, Atlanta, GA, 01/11/2013

Plenary lecturer, ICSFI-14, Gyeongju, Korea, 07/03/2013

R.B. Woodward Lecturer in the Chemical Sciences, Harvard University, 10/10/2013

 

Sample Publications (total 200+)

·         M. Muntwiler, Q. Yang, W. A. Tisdale, X.-Y. Zhu, “Coulomb barrier for charge separation at an organic semiconductor interface,” Phys. Rev. Lett. 2008, 101, 196403.

·         W. A. Tisdale, K. J. Williams, B. A. Timp, D. J. Norris, E. S. Aydil, X.-Y. Zhu, “Hot electron transfer from semiconductor nanocrystals,” Science 2010, 328, 1543-1547.

  • W.-L. Chan, M. Ligges, A. Jailaubekov, L. Kaake, L. Miaja-Avila, X.-Y. Zhu, “Observing the Multi-Exciton State in Singlet Fission and Ensuing Ultrafast Multi-Electron Transfer,” Science 2011, 334, 1541-1545.
  • L. Miaja-Avila, J. Tritsch, A. Wolcott, W.-L. Chan, C. A. Nelson, X.-Y. Zhu, “Direct mapping of hot electron relaxation and multiexciton generation dynamics in PbSe quantum dots,” Nano Lett. 2012, 12, 1588-1591.
  • W.-L. Chan, M. Ligges, X.-Y. Zhu, “The energy barrier in singlet fission can be overcome through coherent coupling and entropic gain,” Nature Chem. 2012, 4, 840-845.
  • C. A. Nelson, X.-Y. Zhu, “Reversible electronic traps in PbS quantum dot solids induced by an order-disorder phase transition in capping molecules,” J. Am. Chem. Soc. 2012, 134, 7792-7795.
  • W.-L. Chan, J. R. Tritsch, X.-Y. Zhu, “Harvesting singlet fission for solar energy conversion: one versus two electron transfer from the quantum mechanical superposition,” J. Am. Chem. Soc. 2012, 134, 18295–18302.
  • A. Jailaubekov, A. P. Willard, J. Tritsch, W.-L. Chan, N. Sai, R. I. Gearba, L. G. Kaake, K. J. Williams, K. Leung, P. J. Rossky, X.-Y. Zhu, “Hot charge transfer excitons set the time limit for charge separation at donor/acceptor interfaces in organic photovoltaics,” Nature Mater. 2013, 12, 66-73.
  • M. Tuan Trinh, M. Y. Sfeir, J. J. Choi, J. S. Owen, X.-Y. Zhu, “A hot electron-hole pair breaks the symmetry of a semiconductor quantum dot,” Nano Lett. 2013, 13, 6091-6097.
  • J. R. Tritsch, W.-L. Chan, X. Wu, N. R. Monahan, X.-Y. Zhu, “Harvesting singlet fission for solar energy conversion via triplet energy transfer,” Nature Commun. 2013, 4, 2679.

 

Synergistic activities

·         Journal Editorial/Advisory Boards: Prog. Surf. Sci. (2006- ); Acc. Chem. Res. (2009-); Chem. Phys. (2013-)

·         Symposium Organizer: 236th, 235th, 221st ACS National Meeting; MRS Spring Meeting (2009) and Fall Meeting (2005); 49th SPIE. Symposium (2004); 4th International Symposium on Ultrafast Surface Dynamics (2003);

·         Guest Lecturer: Asian Pacific Regional College on Science at the Nanoscale (2006).

·         Co-founder & Chief Technology Officer, MicroSurfaces, Inc. (2001-present).

·         International Steering Committee: Symp. on Ultrafast Surface Dynamics (2004-present)

 

Research Interests

Light-matter interaction, solar energy conversion, ultrafast spectroscopy. A main research thrust is to establish new photophysical mechanisms that may be utilized to revolutionize solar energy conversion or light emission. As examples, recent discoveries in our lab showed how an electron and a hole is bound by the Coulomb potential across an organic semiconductor interface, how one can extract hot electrons from a photoexcited quantum dot, how an exciton can split into two via the singlet fission process, and how charge carriers can recombine in semiconductor nanostructures for laser emission.

 

 
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