Speaker
Glenda De los Reyes
(Physics Department, University of Alberta)
Description
We use time-resolved photoluminescence (TRPL) spectroscopy to study the effects of surface passivation and nanocrystal (NC) size on the ultrafast PL dynamics of colloidal SiNCs. The SiNCs were passivated by dodecylamine and ammonia, and exhibit blue emission centered at ~473 nm and ~495 nm, respectively. For both functionalizations, increasing the size of the NCs from ~3 nm to ~6 nm did not result in a PL red-shift, but instead show an identical spectral profile. More interestingly, the nanosecond PL decay dynamics are size- and wavelength-independent with a radiative recombination rate on the order of ~108/s, characteristic of PL from charge transfer states associated with silicon oxynitride bond. Based on TRPL and fluence-dependent measurements, we hypothesize that electrons are first photoexcited within the SiNCs and then rapidly transferred to silicon oxynitride bonds at the surface, creating charge transfer states responsible for the nanosecond blue PL.
Primary author
Glenda De los Reyes
(Physics Department, University of Alberta)
Co-authors
Prof.
Frank Hegmann
(Physics Department, University of Alberta)
Prof.
Jonathan Veinot
(Chemistry Department, University of Alberta)
Dr
Lyubov Titova
(Department of Physics, University of Alberta)
Ms
MengXing Na
(Physics Department, University of Alberta)
Dr
Mita Dasog
(Chemistry Department, University of Alberta)
