3 research outputs found
Direct Realization of Complete Conversion and Agglomeration Dynamics of SnO<sub>2</sub> Nanoparticles in Liquid Electrolyte
The conversion reaction is important
in lithium-ion batteries because
it governs the overall battery performance, such as initial Coulombic
efficiency, capacity retention, and rate capability. Here, we have
demonstrated in situ observation of the complete conversion reaction
and agglomeration of nanoparticles (NPs) upon lithiation by using
graphene liquid cell transmission electron microscopy. The observation
reveals that the Sn NPs are nucleated from the surface of SnO<sub>2</sub>, followed by merging with each other. We demonstrate that
the agglomeration has a stepwise process, including rotation of a
NP, formation of necks, and subsequent merging of individual NPs
Quantum Dot/Siloxane Composite Film Exceptionally Stable against Oxidation under Heat and Moisture
We report on the fabrication of a
siloxane-encapsulated quantum
dot (QD) film (QD-silox film), which exhibits stable emission intensity
for over 1 month even at elevated temperature and humidity. QD-silox
films are solidified via free radical addition reaction between oligosiloxane
resin and ligand molecules on QDs. We prepare the QD-oligosiloxane
resin by sol–gel condensation reaction of silane precursors
with QDs blended in the precursor solution, forgoing ligand-exchange
of QDs. The resulting QD-oligosiloxane resin remains optically clear
after 40 days of storage, in contrast to other QD-containing resins
which turn turbid and ultimately form sediments. QDs also disperse
uniformly in the QD-silox film, whose photoluminescence (PL) quantum
yield (QY) remains nearly unaltered under harsh conditions; for example,
85 °C/5% relative humidity (RH), 85 °C/85% RH, strongly
acidic, and strongly basic environments for 40 days. The QD-silox
film appears to remain equally emissive even after being immersed
into boiling water (100 °C). Interestingly, the PL QY of the
QD-silox film noticeably increases when the film is exposed to a moist
environment, which opens a new, facile avenue to curing dimmed QD-containing
films. Given its excellent stability, we envision that the QD-silox
film is best suited in display applications, particularly as a PL-type
down-conversion layer
Quantum Dot/Siloxane Composite Film Exceptionally Stable against Oxidation under Heat and Moisture
We report on the fabrication of a
siloxane-encapsulated quantum
dot (QD) film (QD-silox film), which exhibits stable emission intensity
for over 1 month even at elevated temperature and humidity. QD-silox
films are solidified via free radical addition reaction between oligosiloxane
resin and ligand molecules on QDs. We prepare the QD-oligosiloxane
resin by sol–gel condensation reaction of silane precursors
with QDs blended in the precursor solution, forgoing ligand-exchange
of QDs. The resulting QD-oligosiloxane resin remains optically clear
after 40 days of storage, in contrast to other QD-containing resins
which turn turbid and ultimately form sediments. QDs also disperse
uniformly in the QD-silox film, whose photoluminescence (PL) quantum
yield (QY) remains nearly unaltered under harsh conditions; for example,
85 °C/5% relative humidity (RH), 85 °C/85% RH, strongly
acidic, and strongly basic environments for 40 days. The QD-silox
film appears to remain equally emissive even after being immersed
into boiling water (100 °C). Interestingly, the PL QY of the
QD-silox film noticeably increases when the film is exposed to a moist
environment, which opens a new, facile avenue to curing dimmed QD-containing
films. Given its excellent stability, we envision that the QD-silox
film is best suited in display applications, particularly as a PL-type
down-conversion layer