1. Ultrafast terahertz snapshots of excitonic Rydberg states and electronic coherence in an organometal halide perovskite
- Author
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Jigang Wang, Joong M. Park, Joseph Shinar, Long Men, Yaroslav Mudryk, Liang Luo, Ilias E. Perakis, Ruth Shinar, Xin Zhao, Zhaoyu Liu, Kai-Ming Ho, Yongxin Yao, and Javier Vela
- Subjects
Terahertz radiation ,Phonon ,Science ,Quantum dynamics ,Exciton ,Dephasing ,General Physics and Astronomy ,02 engineering and technology ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Condensed Matter::Materials Science ,symbols.namesake ,0103 physical sciences ,010306 general physics ,Condensed Matter::Quantum Gases ,Physics ,Multidisciplinary ,business.industry ,General Chemistry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Photoexcitation ,Semiconductor ,Rydberg formula ,symbols ,Atomic physics ,0210 nano-technology ,business - Abstract
How photoexcitations evolve into Coulomb-bound electron and hole pairs, called excitons, and unbound charge carriers is a key cross-cutting issue in photovoltaics and optoelectronics. Until now, the initial quantum dynamics following photoexcitation remains elusive in the hybrid perovskite system. Here we reveal excitonic Rydberg states with distinct formation pathways by observing the multiple resonant, internal quantum transitions using ultrafast terahertz quasi-particle transport. Nonequilibrium emergent states evolve with a complex co-existence of excitons, carriers and phonons, where a delayed buildup of excitons under on- and off-resonant pumping conditions allows us to distinguish between the loss of electronic coherence and hot state cooling processes. The nearly ∼1 ps dephasing time, efficient electron scattering with discrete terahertz phonons and intermediate binding energy of ∼13.5 meV in perovskites are distinct from conventional photovoltaic semiconductors. In addition to providing implications for coherent energy conversion, these are potentially relevant to the development of light-harvesting and electron-transport devices., The generation of bound electron and hole pairs—excitons—is a key process in photovoltaic technologies, yet it is challenging to follow their initial dynamics. Here, Luo et al. probe the Rydberg eigenstates that characterize the excitonic transport and coherent conversion in a perovskite material.
- Published
- 2017
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