Multiple exciton generation in chiral carbon nanotubes: Density functional theory based computation.

We use a Boltzmann transport equation (BE) to study time evolution of a photo-excited state in a nanoparticle including phonon-mediated exciton relaxation and the multiple exciton generation (MEG) processes, such as exciton-to-biexciton multiplication and biexciton-to-exciton recombination. BE collision integrals are computed using Kadanoff-Baym-Keldysh many-body perturbation theory based on density functional theory simulations, including exciton effects. We compute internal quantum efficiency (QE), which is the number of excitons generated from an absorbed photon in the course of the relaxation. We apply this approach to chiral single-wall carbon nanotubes (SWCNTs), such as (6,2) and (6,5). We predict efficient MEG in the (6,2) and (6,5) SWCNTs within the solar spectrum range starting at the 2Eg energy threshold and with QE reaching ∼1.6 at about 3Eg, where Eg is the electronic gap.

Citation

Andrei Kryjevski, Deyan Mihaylov, Svetlana Kilina, Dmitri Kilin. Multiple exciton generation in chiral carbon nanotubes: Density functional theory based computation. The Journal of chemical physics. 2017 Oct 21;147(15):154106

PMID: 29055322

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