A series of mesoporous WO3 catalysts were facilely synthesized by a hydrothermal method using mesoporous silica KIT-6 as a hard template and silicotungstic acid as a precursor.
We have investigated
the defect perovskites A3M2I9 (A
= Cs, Rb; M = Bi, Sb) as materials for radiation
detection. The phase purity of Bridgman-grown A3M2I9 single crystals was confirmed via high-resolution synchrotron
X-ray diffraction, while density functional theory calculations (DFT)
show surprisingly dispersive bands in the out-of-plane direction for
these layered materials, with low effective masses for both holes
and electrons. Accordingly, each of the four A3M2I9 defect perovskites showed response to 241Am α-particle irradiation for hole and electron electrode configurations,
a remarkable ambipolar response that resembles the 3D halide perovskites.
The electron response spectra were used to estimate the mobility–lifetime
product (μτ)e for electrons in these materials,
with Rb3Bi2I9 showing the lowest
(μτ)e value of 1.7 × 10–6 cm2 V–1 and Cs3Bi2I9 the highest (μτ)e of 5.4 ×
10–5 cm2 V–1. The rise
time of the α-particle-generated pulse was used to estimate
the electron mobility μe of the A3M2I9 defect perovskites, which ranged from 0.32 cm2 V–1s–1 for Rb3Sb2I9 to 4.3 cm2 V–1s–1 in Cs3Bi2I9. Similar analysis of the hole response spectra yielded (μτ)h values for each A3M2I9 compound,
with Cs3Bi2I9 again showing the highest
(μτ)h value of 1.8 × 10–5 cm2 V–1, while Rb3Bi2I9 showed the lowest (μτ)h with 2.0 × 10–6 cm2 V–1. Rise time analysis gave hole mobilities ranging from 1.7 cm2 V–1 s–1 for Cs3Bi2I9 to 0.14 cm2 V–1 s–1 for Cs3Sb2I9. Comparing the experimental electron and hole mobilities to the
effective masses obtained from DFT calculations revealed sizable discrepancies,
possibly indicating self-trapping of charge carriers due to electron–phonon
interactions. The α-particle response of the A3M2I9 defect perovskites demonstrates their potential
as semiconductor radiation detectors, with Cs3Bi2I9 and Cs3Sb2I9 showing
the most promise.
Karstification is adopted to develop a new synthetic strategy for single-crystalline WO(3) octahedra bound with {111} facets from irregular-shaped commercial WO(3) particles.
LSCF and 3DOM-LSCF catalysts can significantly improve the catalytic performance and 100% selectivity for the reduction of CO2 with H2O vapor to CH4 under thermal and photo-thermal reaction conditions.
Single crystalline zinc stannate (Zn(2)SnO(4) and ZnSnO(3)) nanoparticles were synthesized by a simple one-step hydrothermal reaction with a high production yield. Zn(2)SnO(4) is a (111) face-exposed octahedron, whereas ZnSnO(3) is a (100) face-exposed hexahedron structure. In particular, Zn(2)SnO(4) exhibits an efficient performance for applications in dye-sensitized solar cells.
Tellurium dioxide (TeO2) nanowires with a tetragonal structure have been grown by thermally evaporating tellurium metal at 400°C in air. The nanowires produced have diameters ranging from 30to200nm and have lengths of several tens of micrometers. Gas sensors were fabricated using the obtained TeO2 nanowires. The sensing behavior to NO2, NH3, and H2S gases at room temperature showed typical characteristics of a p-type semiconductor. The results demonstrate the potential to develop TeO2 nanowire based gas sensors with low power consumption.
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