nn9b09614_si_001.pdf (7.34 MB)
Bright Silicon Nanocrystals from a Liquid Precursor: Quasi-Direct Recombination with High Quantum Yield
journal contribution
posted on 2020-03-17, 20:47 authored by Todd A. Pringle, Katharine I. Hunter, Alexandra Brumberg, Kenneth J. Anderson, Jeffrey A. Fagan, Salim A. Thomas, Reed J. Petersen, Mahmud Sefannaser, Yulun Han, Samuel L. Brown, Dmitri S. Kilin, Richard D. Schaller, Uwe R. Kortshagen, Philip Raymond Boudjouk, Erik K. HobbieSilicon
nanocrystals (SiNCs) with bright bandgap photoluminescence
(PL) are of current interest for a range of potential applications,
from solar windows to biomedical contrast agents. Here, we use the
liquid precursor cyclohexasilane (Si6H12) for
the plasma synthesis of colloidal SiNCs with exemplary core emission.
Through size separation executed in an oxygen-shielded environment,
we achieve PL quantum yields (QYs) approaching 70% while exposing
intrinsic constraints on efficient core emission from smaller SiNCs.
Time-resolved PL spectra of these fractions in response to femtosecond
pulsed excitation reveal a zero-phonon radiative channel that anticorrelates
with QY, which we model using advanced computational methods applied
to a 2 nm SiNC. Our results offer additional insight into the photophysical
interplay of the nanocrystal surface, quasi-direct recombination,
and efficient SiNC core PL.