21 research outputs found
Preparation of Boron-Doped Porous Titania Networks Containing Gold Nanoparticles with Enhanced Visible-Light Photocatalytic Activity
The ability to decrease the electron/hole recombination
rate, and
decrease the band gap of titania to allow photoactivity on irradiation
with visible light is attracting more and more attention. Here, boron
doping of the titania, the deposition of gold nanoparticles, along
with a meso-macroporous structure were obtained using a facile agarose
gel templating process combined with sol–gel chemistry. The
Au/B/TiO<sub>2</sub> nanocomposites were characterized using SEM,
TEM, XRD, N<sub>2</sub> gas sorption, diffuse UV–vis, photoluminescence,
and SIMS. The photocatalytic activity was assessed by degradation
of an organic probe molecule (methylene blue) under visible light
(λ > 420 nm). The resulting materials achieved photocatalytic
activities up to 50% greater than the commercial Degussa P25 under
visible light. The enhancement in photocatalytic activity was primarily
attributed to the decrease in band gap as a result of the boron doping
and its influence on the anatase to rutile phase formation: The doped
materials were highly crystalline and an optimum anatase to rutile
ratio (3:1) was obtained with 0.25 wt % boron in the sample calcined
at 650 °C. In addition, the presence of the gold nanoparticles
decreased recombination between the photoexcited electrons and holes,
which further improved the photocatalytic activity
Blue Thermally Activated Delayed Fluorescence Polymers with Nonconjugated Backbone and Through-Space Charge Transfer Effect
We demonstrate novel
molecular design for thermally activated delayed
fluorescence (TADF) polymers based on a nonconjugated polyethylene
backbone with through-space charge transfer effect between pendant
electron donor (D) and acceptor (A) units. Different from conventional
conjugated D–A polymers with through-bond charge transfer effect,
the nonconjugated architecture avoids direct conjugation between D
and A units, enabling blue emission. Meanwhile, spatial π–π
interaction between the physically separated D and A units results
in both small singlet–triplet energy splitting (0.019 eV) and
high photoluminescence quantum yield (up to 60% in film state). The
resulting polymer with 5 mol % acceptor unit gives efficient blue
electroluminescence with Commission Internationale de l’Eclairage
coordinates of (0.176, 0.269), together with a high external quantum
efficiency of 12.1% and low efficiency roll-off of 4.9% (at 1000 cd
m<sup>–2</sup>), which represents the first example of blue
TADF nonconjugated polymer
Probing the Effects of Templating on the UV and Visible Light Photocatalytic Activity of Porous Nitrogen-Modified Titania Monoliths for Dye Removal
Porous nitrogen-modified titania
(N-titania) monoliths with tailored morphologies were prepared using
phase separation and agarose gel templating techniques. The doping
and templating process were simultaneously carried out in a one-pot
step using alcohol amine-assisted sol–gel chemistry. The amount
of polymer used in the monoliths that were prepared using phase separation
was shown to affect both the physical and optical properties: higher
polyÂ(ethylene glycol) content increased the specific surface area,
porosity, and visible light absorption of the final materials. For
the agarose-templated monoliths, the infiltration conditions affected
the monolith morphology. A porous monolith with high surface area
and the least shrinkage was obtained when the N containing alkoxide
precursor was infiltrated into the agarose scaffolds at 60 °C.
The effect of the diverse porous morphologies on the photocatalytic
activity of N-titania was studied for the decomposition of methylene
blue (MB) under visible and UV light irradiation. The highest visible
light activity was achieved by the agarose-templated N-titania monolith,
in part due to higher N incorporation. This sample also showed better
UV activity, partly because of the higher specific surface area (up
to 112 m<sup>2</sup> g<sup>–1</sup>) compared to the phase
separation-induced monoliths (up to 103 m<sup>2</sup> g<sup>–1</sup>). Overall, agarose-templated, porous N-titania monoliths provided
better features for effectively removing the MB contaminant
The funnel plot of OS on patients with newly diagnosed GB.
<p>The funnel plot of OS on patients with newly diagnosed GB.</p
The PRISMA flow chart of the meta-analysis.
<p>The PRISMA flow chart of the meta-analysis.</p
The pooled HR of median OS comparing BV with ST in patients with GB.
<p>The pooled HR of median OS comparing BV with ST in patients with GB.</p
The pooled HR of median PFS comparing BV with ST in patients with GB.
<p>The pooled HR of median PFS comparing BV with ST in patients with GB.</p
The incidence of all severe AEs in patients with newly diagnosed GB.
<p>The incidence of all severe AEs in patients with newly diagnosed GB.</p
The pooled analysis of OS rate comparing BV with ST in patients with GB at different follow-ups.
<p>The pooled analysis of OS rate comparing BV with ST in patients with GB at different follow-ups.</p