Biexciton Binding of Dirac fermions Confined in Colloidal Graphene Quantum Dots
- 23 July 2015
- journal article
- research article
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 15 (8), 5472-5476
- https://doi.org/10.1021/acs.nanolett.5b01888
Abstract
We present transient absorption measurements and microscopic theory of biexciton binding in triangular colloidal graphene quantum dots consisting of 168 sp2-hybridized C atoms. We observe optical transitions from the lowest orbitally dark singlet exciton states to states below the energy of an unbound dark+bright singlet-exciton pair. Through microscopic calculations of the low-energy exciton and biexciton states via tight-binding, Hartree–Fock, and configuration interaction methods, the spectra reveal a biexciton consisting primarily of a dark-bright singlet-pair bound by ∼0.14 eV.Funding Information
- University of Ottawa
- Natural Sciences and Engineering Research Council of Canada
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