Post Doc. Georgia Institute of Technology (2011-2012)
Post Doc. University of Texas at Austin (2008-2010)
Ph.D. Physical Chemistry, University of Notre Dame (2008)
M.S. Physical Chemistry, Nanjing University (2002)
B.S. Chemistry, Nanjing University (1998)
- Surface chemistry
- Reaction kinetics
- Scanning probe microscopy
- Organic solar cells
- Organic semiconductors
1. The exciton dissociation and energy transfer in organic solar cells at molecular level.
We study the morphology-structure-property correlations in organic electronic material, in particular, photovoltaic polymer materials, at the molecular level. The performances of organic electronic devices are strongly influenced by the domain morphology, molecular packing within and between domains, and the conformational structures of the polymer molecules. A deep understanding of the structure-conformation-property relationships at the scale of single molecule level is imperative for the future fulfillments of the idea of rational molecular design. A monolayer of donor/acceptor polymer blend will be probed by a combination of conductive AFM and single molecule spectroscopy. The topographic images and the photocurrent images under various lighting conditions will be recorded and mapped together to provide new insights into the impact of molecular packing on the local photovoltaic performance of the polymer donor/acceptor blend.
2. Air-stable dopants for organic electronic materials.
For organic charge-transport materials, the injection of holes and electrons from the electrodes leads to the formation of molecular cations and anions, respectively. Doping is one of the most effective methods to improve the properties of organic electronic materials. Adding dopants into organic materials, in principle similar to the doping in inorganic semiconductors, increases the density of charge carrier and changes the Fermi levels of the doped organic electronic materials. Air-stable dopant precursors are a group of materials that can release active dopants under thermal treatments and irradiations. We will develop and characterize air-stable organic dopants that will (1) replace conventional air-sensitive dopants which complicate the device processing, and (2) result in more stable and spatially-localized doped devices so that a better performance and longer lifetime are expected.
- S. Guo, S. K. Mohapatra, A. Romanov, T. V. Timofeeva, K. I. Hardcastle, K. Yesudas, C. Risko, J. L. Brédas, S. R. Marder, S. Barlow, “n-Doping of Organic Electronic Materials using Air-Stable Organometallics: A Mechanistic Study of Reduction by Dimeric Sandwich Compounds”, Chemistry - A European Journal, in press.
- S. Guo, S. B. Kim, S. K. Mohapatra, Y. Qi, T. Sajoto, A. Kahn, S. R. Marder, S. Barlow, “n-Doping of Organic Electronic Materials using Air-Stable Organometallics”, Advanced Materials, 24, 699(2012)
- S. Guo, O. Fabian, Y.-L. Chang, J.-T. Chen, W. M. Lackowski, and P. F. Barbara, “Electrogenerated Chemiluminescence of Conjugated Polymer Films from Patterned Electrodes", Journal of the American Chemical Society 133, 11994 (2011)
- S. Guo and S. A. Kandel, “Scanning Tunneling Microscopy of Mixed Valence Dinuclear Organometallic Cations and Counterions on Au(111),” Journal of Physical Chemistry Letters 1, 420 (2010)