Our research focuses on understanding the fundamental electronic processes, such as exciton transport and charge transfer, in molecular solids, conjugated polymers, organic-inorganic hybrid systems and 2-D layered crystals. These materials can be potentially used in next generation devices for applications ranging from light harvesting (e.g. solar energy, photocatalysis) to flexible electronics. However, the lack of fundamental understandings in the electron dynamics of these materials can hinder future applications. Using novel experimental techniques such as time-resolved two photon photoemission spectroscopy, time-resolved electrical measurements and optical spectroscopy, we probe the dynamics of photoexcited electrons and molecules in an ultrafast timescale (10-14 – 10-9 s). A better understanding of these processes will help us to design cost-effective ways to produce energy.
Research sponsored by:
Recent Research Projects
Full publication list can be found at:
1. Coherent Exciton Transport and Charge Transfer in Organic Semiconductors
Kattle, B., Qin, L., Kafle, T. R., & Chan, W. -L.
Graphene Field-Effect Transistor as a High-Throughput Platform to Probe Charge Separation at Donor-Acceptor Interfaces
J. Phys. Chem. Lett. 9, 1633-1641 (2018)
Wang, T., Kafle, T., Kattel, B., & Chan, W.-L.
A Multi-Dimensional View of Charge Transfer Excitons at Organic
J. Am. Chem. Soc., 139, 4098-4106 (2017)
Wang, T., Kafle, T., Kattel, B., & Chan, W.-L.,
Observation of an Ultrafast Exciton Hopping Channel in Organic Semiconducting Crystals
J. Phys. Chem. C, 120, 7491-7499 (2016)
Wang, T., & Chan, W. L.,
Dynamical Localization Limiting the Coherent Transport Range of Excitons in Organic Crystal.
J. Phys. Chem. Lett., 5, 1812-1818 (2014)
2. Hybrid organic-2D van der Waals interfaces
Kafle, T. R., Kattel, B., Yao, P., Zereshki, P., Zhao, H., & Chan, W. -L.
Effect of the Interfacial Energy Landscape on Photo-induced Charge
Generation at the ZnPc-MoS2 Interface
J. Am. Chem. Soc., 141, 11328-11336 (2019) [Press Release]
Kafle, T. R., Kattel, B., Lane, S., Wang, T., Zhao, H., & Chan, W. -L.
Charge Transfer Exciton and Spin Flipping at Organic-Transition Metal
ACS Nano, 11, 10184-10192 (2017)
Biancardi, A., Caraiani, C., Chan, W.-L., & Caricato, M.
How Number of Layers and Relative Position Modulate the Interlayer Electron Transfer in π-Staked 2D Materials
J. Phys. Chem. Lett., 8, 1365-1370 (2017)
Wang, T., Liu, Q., Caraiani, C., Zhang, Y., Wu, J., & Chan, W.-L.
Effect of Interlayer Coupling on Ultrafast Charge Transfer from Semiconducting Molecules to Mono- and Bilayer Graphene
Phys. Rev. Appl. 4, 014016 (2015)
3. Hybrid-organometallic perovskite, nano-materials optoelectronic devices
Qin, L., Wu, L., Kattel, B., Li, C., Zhang, Y., Hou, Y., Wu, J., & Chan, W. –L.
Using Bulk-Heterojunction and Selective Electron Trapping to Enhance
the Responsivity of Perovskite-Graphene Photodetector
Adv. Funct. Mater., 27, 1704173 (2017).
Gong, M., Liu, Q., Cook, B., Kattel, B., Wang, T., Chan, W.-L., Ewing, D., Casper, M., Stramel, A., & Wu, J.
All-printable ZnO quantum dots/Graphene van der Waals heterostructures for ultrasensitive detection of ultraviolet light
ACS Nano, 11, 4114-4123 (2017).
PI: Wai-Lun Chan
Tika Kafle (postdoc at University of Colorado Boulder)
Ti Wang (researcher at Wuhan University)
Visiting PhD student:
Liang Qin (lecturer at Beijing Jiaotong University)
Aaron Gehrke (graduate student at University of Washington)
Claudiu Caraiani (graduate student at University of Bucharest)
Will Burg (graduate student at Univ. of Texas, Austin)
Cole Lindsey (graduate student at KU)
1. Spontaneous Exciton Dissociation at Organic Semiconductor Interfaces Facilitated by the Orientation of the Delocalized Electron-hole Wavefunction,
accepted by Adv. Energy Mater.