2017/07/26 by Andrei Kryjevski, Deyan Mihaylov, Svetlana Kilina +1
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1063/1.4997048
20 pages, 6 figures. 7/20/2017: arXiv admin note: substantial text overlap with arXiv:1703.04693. In v2 text changed to avoid text overlap with our earlier work on the same subject arXiv:1703.04693
arxiv created 2017/07/26 · arxiv updated 2017/11/22
We use 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 (MBPT) based on density functional theory (DFT) 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 2 Eg energy threshold and with QE reaching ∼ 1.6 at about 3 Eg, where Eg is the electronic gap.