Peking University, Beijing, China, B.S.
University of Rochester, Rochester, NY, Ph.D.
Tel. (574) 631-2657
Research Pages: www.nd.edu/~lhuang2
Ultrafast imaging of energy and charge transfer in solar energy harvesting systems
In-situ energy transfer and charge carrier dynamics in solar energy conversion systems ― We employ ultrafast spectroscopy combined with optical microscopy and scanning probe microscopy to achieve simultaneous ultrafast time resolution and nanometer spatial resolution. This research program aims at providing spatial maps of carrier dynamics, and allowing for imaging energy and charge propagation in space directly. Ultimately, this program is directed towards resolving correlations between structural hierarchies and the fundamental mechanisms in solar energy harvesting architectures and providing guidelines for designing more efficient solar harvesting devices.
Recent Accomplishments | Top |
Cofactor-specific function mapping in single photosynthetic reaction center crystals ― High-resolution mapping of cofactor-specific photochemistry in photosynthetic reaction centers (RCs) from Rhodobacter sphaeroides was achieved by polarization selective ultrafast spectroscopy in single crystals at cryogenic temperatures. By exploiting the fixed orientation of cofactors within crystals, we isolated a single transition within the multi-cofactor manifold, and elucidated the site-specific photochemical functions of the cofactors associated with the symmetry-related active A and inactive B branches.
Morphology dependent charge dynamics in organic photovoltaics ― Transient absorption microscopy (TAM) experiments have been performed on thermally annealed poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blends. By directly comparing spatially resolved charge dynamics to ensemble dynamics, the results demonstrate that the apparent lifetimes measured by ensemble measurements can be misleading due to averaging over microscopically different areas.
Environment dependent energy relaxation pathways in single nanostructures ― We have applied transient absorption microscopy (TAM) to probe environmental dependent energy relaxation pathways in low-dimensional nanostructures such as single-walled carbon nanotubes and graphene. The environment was found to play an important role in modulating carrier dynamics. For example, we observed that the hot phonon effect occurs at much lower excitation intensity for suspended graphene compared to substrate-supported graphene. These results show the importance of the environment in controlling the properties of nanomaterials.
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H. Shi, R. Yan, S. Bertolazzi, G. Gao, A. Kis, D. Jena, H. Xing and L. Huang
Exciton dynamics in suspended monolayer and few-layer MoS2 2D crystals
ACS Nano 2013 7, 1072 link
B. Gao, G.V. Hartland and L. Huang
Transient absorption microscopy studies of individual chirality assigned single-walled carbon nanotubes
ACS Nano. 2012 6, 5083 link
L. Huang, N. Ponomarenko, G.P. Wiederrecht and D.M. Tiede
Cofactor-specific photochemical function resolved by ultrafast spectroscopy in photosynthetic reaction center crystals
Proc. Natl. Acad. Sci. 2012 109, 4851 link
C. Wong, S.S. Lo and L. Huang
Ultrafast spatial imaging of charge dynamics in heterogeneous polymer blends
J. Phys. Chem. Lett. 2012 3, 879 link
B. Gao, G.V. Hartland, T. Fang, M. Kelly, D. Jena, H. Xing and L. Huang
Studies of intrinsic hot phonon dynamics in suspended graphene by transient absorption microscopy
Nano Lett. 2011 11, 3184 link
I. Kim, S.L. Bender, J. Hranisavljevic, L.M. Utschig, L.B. Huang, G.P. Wiederrecht and D.M. Tiede
Metal nanoparticle plasmon-enhanced light-harvesting in a Photosystem I thin film
Nano Lett. 2011 11, 3091 link