posted on 2020-03-09, 18:58authored byBotao Ji, Somnath Koley, Ilya Slobodkin, Sergei Remennik, Uri Banin
Epitaxial growth
of a protective semiconductor shell on a colloidal
quantum dot (QD) core is the key strategy for achieving high fluorescence
quantum efficiency and essential stability for optoelectronic applications
and biotagging with emissive QDs. Herein we investigate the effect
of shell growth rate on the structure and optical properties in blue-emitting
ZnSe/ZnS QDs with narrow emission line width. Tuning the precursor
reactivity modifies the growth mode of ZnS shells on ZnSe cores transforming
from kinetic (fast) to thermodynamic (slow) growth regimes. In the
thermodynamic growth regime, enhanced fluorescence quantum yields
and reduced on–off blinking are achieved. This high performance
is ascribed to the effective avoidance of traps at the interface between
the core and the shell, which are detrimental to the emission properties.
Our study points to a general strategy to obtain high-quality core/shell
QDs with enhanced optical properties through controlled reactivity
yielding shell growth in the thermodynamic limit.