<p>Two
quantum dots, both alike in composition, but differing in structure, where we
lay our scene. From broader classes, to bring deeper understanding, to the
crystalline core that drives the quantum dot's sheen. In this contribution we
examine two families of silicon quantum dots (SiQDs) that bring to mind the
Capulets and the Montagues in Shakespeare’s Romeo and Juliet because of their
stark similarities and differences. SiQDs are highly luminescent,
heavy-metal-free and based upon earth-abundant elements. As such, they have attracted attention for far
reaching applications ranging from biological imaging to luminescent solar
concentrators to light-emitting diodes that rely on their size-dependent
optical response. Unfortunately, correlating SiQD “size” to their photoluminescence
maximum is often challenging. Herein, we provide essential structural insight
into the correlation of SiQD dimension and PL maximum through a direct comparison
of samples that exhibit statistically identical physical dimensions (d<sub>TEM</sub>)
and chemical compositions, but different crystallite size (d<sub>XRD</sub>) and
PL maxima. We then expand the scope of
this investigation and systematically compare groupings of SiQDs: one in which
the d<sub>XRD</sub> and d<sub>TEM</sub> agree and one where d<sub>XRD </sub><
d<sub>TEM</sub>. This latter comparison clearly shows d<sub>XRD</sub> better
predicts SiQD optical response when using the well-established effective mass
approximation. </p>
Graphene: Insight into the Cellular Internalization and Cytotoxicity of Graphene Quantum Dots (Adv. Healthcare Mater. 12/2013)
