Ultrafast Bright-to-Dark Exciton Relaxation in Bilayer Borophene Driven by Strong Excitonic Effects.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40391418.
- Also identified by DOI 10.1021/acs.nanolett.5c02115.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Exciton dynamics in the recently discovered bilayer borophene (BL-α<sub>5</sub>, consisting of two stacked <i>v</i><sub>1/12</sub> boron sheets) are of great interest due to this material's promising electronic and optical properties for nano-optoelectronic applications. Using a GW plus real-time Bethe-Salpeter equation (GW-rtBSE) approach and <i>ab initio</i> nonadiabatic molecular dynamics (NAMD), we identify a Frenkel-type lowest-energy bright exciton and a spatially delocalized dark exciton in BL-α<sub>5</sub>, with large binding energies of ∼700 and ∼502 meV, respectively. The electron-hole (e-h) Coulomb interaction (exciton effect) dominates over electron-phonon (e-ph) scattering, playing a pivotal role in an ultrafast bright-to-dark exciton transition with a relaxation time of ∼150 fs. Furthermore, the dark excitons undergo nonradiative recombination on a picosecond time scale (∼14 ps at room temperature). These results provide a theoretical foundation for potential nano-optoelectronic and light-energy harvesting applications of bilayer borophene.