Carrier Dynamics

We are deeply into carrier dynamics calculations and the related methodology develoments. This might include: the carrier mobility in a disordered polymer system, the carrier mobility in a connected quantum dot supercrystal, the carrier cooling in an inorganic nanocrystal, the carrier trapping by a deep defect state, and the carrier mobility in an organic crystal. Different methods are used to tackle such problems. This includes the electron-phonon coupling, the Fermi golden rule, the Marcus theory, and the time domain simulations.

A few examples are given here for the systems studied in this group.

A multiscale scheme of simulating localized state hopping assisted by phonon absorption and emission. This starts from charge motif calculation, to localized state calculation, then electron-phonon interaction, then hopping rate using Fermi golden rule, then assembling of the microsystems into meso-systems to reduce fluctuations.

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This calculates the electron coupling from two CdSe quantum dots connected by a molecule. Such coupling, along with the re-organization energy can then be used with Marcus theory to calculate the electron hopping between these two dots.

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The time domain simulation to study the carrier transport. In this approach, the nuclei are moved by Newton's law, while the electrons are moved by time dependent Schrodinger's equation. As a result, all effects of the electron-phonon couplings are included, so is the coherent effect in the transport.