Visible light-activated sulfur doped TiO2 nanocrystalline films were synthesized by a sol–gel method based on the self-assembly technique with nonionic surfactant to control nanostructure and an inorganic sulfur source (i.e., H2SO4). The films were characterized by UV–vis diffuse reflectance, XRD, TEM, Raman, AFM, ESEM, XPS, FT-IR, EDX, EPR and porosimetry. The results showed that the physicochemical properties of the films, such as BET surface area, porosity, crystallite size and pore size distribution could be controlled by the calcination temperature. The highest surface area, smallest crystallite size and narrow pore size distribution were obtained for sulfur doped TiO2 films calcined at 350 °C, which exhibit very smooth surface with minimal roughness (

Innovative visible light-activated sulfur doped TiO2 films for water treatment

Crystal defects have been extensively proved to have great influence on semiconductor photocatalysis. To optimize the reactivity of crystalline photocatalysts and achieve ideal solar energy conversion, crystal defect engineering has initiated a considerable interest in real catalysts. Herein, we develop a general strategy to manufacture and mediate crystal defects in the host Bi2MoO6 lattice by varying the cerium dopant content, resulting in greatly improved visible-light-driven photocatalytic performance for the degradation of highly toxic nerve agent simulants (NAS) and organic dyes, as well as bacterial photoinactivation. After careful examination of crystal defect structure and charge carrier dynamics, it was proved that Ce-doping-mediated crystal defects are crucial for controlling the photocatalytic efficiency of aurivillius Bi2MoO6. More importantly, the well-engineered crystal defects not only exert a beneficial influence on the electron dynamics and band structure but also facilitate the one-elec...

Crystal Defect Engineering of Aurivillius Bi2MoO6 by Ce Doping for Increased Reactive Species Production in Photocatalysis

A novel blue-emitting long-lasting proyphosphate phosphor Sr2P2O7:Eu2+.Y3+

Rare earth (RE) doped phosphors and their emerging applications: A review

Microwave dielectric ceramics are considered to be one of the key materials of dielectric resonators/filters and have wide application prospects in fifth generation (5G) mobile communication systems. Here we prepared two kinds of low-sintering temperature and high-performance microwave dielectric ceramics with monoclinic rock salt structure by adding a small amount of V2O5 and 0.6CuO–0.4B2O3 sintering aids to Li2Ti0.75(Mg1/3Nb2/3)0.25O3 (LTMN0.25). The sintering temperature of LTMN0.25 ceramics with 2 wt% V2O5 and 1 wt% 0.6CuO–0.4B2O3 additions could be effectively reduced from 1170 °C to below 910 °C due to the liquid phase effects resulting from the additives. Typically, high performance microwave dielectric properties can be obtained in the LTMN0.25 + 2 wt% V2O5 ceramic sintered at 910 °C for 2 h, with a er ∼ 20.7, a Q × f ∼ 60 460 GHz and a TCF ∼ +4.3 ppm °C−1. The best dielectric properties of er ∼ 19.9, a Q × f ∼ 60 950 GHz and a TCF ∼ −6.1 ppm °C−1 were obtained for the samples with 1 wt% 0.6CuO–0.4B2O3 sintered at 870 °C for 2 h. A prototype dielectric resonator antenna (DRA) was fabricated by LTMN0.25 + 1 wt% 0.6CuO–0.4B2O3 ceramic. The antenna resonated at 10.02 GHz with a bandwidth ∼175 MHz at −10 dB transmission loss (S11). Moreover, the chemical compatibility with Ag powder suggests that the LTMN0.25 + 2 wt% V2O5 and LTMN0.25 + 1 wt% 0.6CuO–0.4B2O3 ceramics may be suitable candidates for low temperature co-fired ceramic technology applications.

https://pubs.rsc.org/en/content/articlepdf/2020/TC/D0TC00326C

Temperature stable Li2Ti0.75(Mg1/3Nb2/3)0.25O3-based microwave dielectric ceramics with low sintering temperature and ultra-low dielectric loss for dielectric resonator antenna applications

Synthesis, X-ray diffraction and photoluminescence investigations of Eu3+-doped SrBPO5 phosphor has been carried out in order to characterize the material. PL emission spectrum of air heated SrBPO5:Eu3+ phosphor exhibits bands at 590, 614, 651 and 702 nm under 238 nm excitation, assigned to the 5D0→7FJ (J=1, 2, 3, 4) transitions of Eu3+ ions. Of these transitions, the emission centered at 614 nm is the most prominent. Photoluminescence decay time and Time-resolved emission spectrometric (TRES) studies of Eu3+ were carried out with λem=614 nm and λex=238 nm. It suggested that Eu3+ ions are present at two different sites and predominantly occupying Sr2+ sites in the host lattice. Judd–Ofelt intensity parameters and other radiative properties were evaluated from the emission spectrum by adopting standard procedure. The trend observed in the J–O parameters (Ω2>Ω4) confirms the covalency exiting between the Eu3+ ion and ligands as well as the asymmetry around the metal ion site. The color coordinates of the system were evaluated (x=0.558 and y=0.355) and plotted on a standard CIE index diagram. The observations showed that the SrBPO5:Eu3+ phosphor is very close to the red emission material. Photoluminescence intensity was compared with that of a commercial red phosphor for commercial utility purpose. It is observed that, the photoluminescence intensity of the prepared phosphor was 60% as compared to the commercial phosphor Y2O3: Eu.

T.K. Seshagiri

Papers

Fluorescence lifetime and Judd–Ofelt parameters of Eu3+ doped SrBPO5

Synthesis and luminescence investigation of RE3+ (EU3+, Tb3+ and Ce3+)-doped lithium silicate (Li2SiO3)

EPR and TSL studies on MgB4O7 doped with Tm: role of BO32- in TSL glow peak at 470K

Synthesis, characterization and studies of radiative properties on Eu3+-doped ZnAl2O4

Photoluminescence, thermally stimulated luminescence and electron paramagnetic resonance of europium-ion doped strontium pyrophosphate