jp7b02433_si_001.pdf (907.73 kB)
On the Molecular Origin of Photoluminescence of Nonblinking Carbon Dot
journal contribution
posted on 2017-04-11, 00:00 authored by Ananya Das, Venkatesh Gude, Debjit Roy, Tanmay Chatterjee, Chayan K. De, Prasun K. MandalThe
molecular origin of the photoluminescence (PL) of carbon dots
(CDs) is not fully understood. In this article it is shown that CDs
are composed of aggregated 2-pyridone derivatives employing π–π
stacking and H-bonding, etc. The PL quantum yield of this CD is quite
high in aqueous medium (∼75%). Unlike literature reports the
PL emission maximum of this CD is excitation wavelength independent,
and PL decay follows a single-exponential decay equation. These CDs
have a long PL lifetime (from ∼10 to 15 ns), so that solvation
is complete before emission. The extent of trap states could be reduced
quite significantly. A high PLQY and long and single-exponential PL
lifetime and it’s polarity dependence would make this CD a
suitable probe for FRET and FLIM. It could be shown that unlike literature
reports this CD as a single particle does not blink. Unlike literature
reports where CDs are bleached within a few seconds these CDs at the
single-particle level are alive for about a few minutes. All these
aggregation-induced much improved optical properties will make this
CD a suitable optical emitter at the ensemble as well as single-particle
level toward bioimaging. As the molecular origin is now known several
optical properties can now be tuned.