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(Ba0.65Sr0.35)TiO3(BST) ceramics doped with MgTiO3were prepared by solid state method. Influence of MgTiO3doped amount on dielectric property and microstructure of BST ceramics were investigated. The results showed that MgTiO3doping could fine crystal grain size and made crystal grain size uniform and pore decrease and density increase. MgTiO3doping could decrease dielectric loss (tanδ) and increase dielectric constant(ϵr) of BST ceramics and increase the alternating current (AC) withstand voltage strength (Eb) and improve the capacitance temperature property. When MgTiO3doping amount was 0.8wt.%, the BST ceramics had good comprehensive property, ϵrof 4350, tanδ of 0.0055, Ebof 5.7×103V/mm (AC), the capacitance temperature property was suited for Y5U. [ABSTRACT FROM AUTHOR]

(1-x) Ba0.65Sr0.35TiO3-xCaCu3Ti4O12(BST-CCTO) ceramics was prepared by traditional solid-state reaction method, the effect of CaCu3Ti4O12(CCTO) doped on microstructure and phase composition and dielectric properties of BST ceramics were investigated by X-ray diffraction(XRD), scanning electron microscope(SEM) and other analytical methods. The results show that the microstructure and the dielectric properties and the optimum sintered temperature of BST ceramic materials would be greatly affected by the CCTO doped amount. Appropriate doping amount can be fully incorporated into the perovskite lattice of BST and had the excellent performance. While excessive CCTO doping could lead to the appearance of second phase, and the second phase was coexisted with BST in the ceramics. BST ceramics had the optimum properties, ϵrof 1992, tan δ of 0.006, Ebof 5.5 kVmm−1(Alternating Current, AC) and the value of ΔC/C ranges was 13.6% and −14.1% in −55°C∼+125°C temperature range and its capacitance temperature property was suited for X7R, the curie temperature was 15°C and the optimum sintered temperature was 1260°C when CCTO doped amount was 1 wt.%. [ABSTRACT FROM AUTHOR]

Single-phase 2Gd 2 O 3 ·(Gd,Tb) 2 (SO 4) 3 ·nH 2 O precursor with strong crystallinity was synthesized by the water-bath method through optimizing the introducing method of Tb3+ doping, where Tb3+ was introduced from Tb(NO 3) 3. The formation process and phase evolution of the precursor were analyzed in detail. Compared with the conventional method of introducing Tb3+ via Tb 4 O 7 , the inhomogeneous doping caused by the appearance of 2Tb 2 O 3 ·(Gd,Tb) 2 (SO 4) 3 ·nH 2 O in the precursor was avoided. Pure Gd 2 O 2 S:Tb nanopowders with layered structure were obtained after calcination in flowing H 2 -Ar. The Gd 2 O 2 S:Tb powder prepared with Tb(NO 3) 3 has higher XEL intensity than that with Tb 4 O 7. Using the synthesized powders as starting material, Gd 2 O 2 S:Tb scintillation ceramics with high relative density (over 99% of the theoretical value) were fabricated by vacuum pre-sintering and HIP post-treatment in an argon atmosphere. The influences of the introducing method of Tb3+ doping on the microstructure, photoluminescence and X-ray excited luminescence of the Gd 2 O 2 S:Tb ceramics were studied. The ceramic sample prepared with Tb(NO 3) 3 has better luminescence properties due to the homogeneous doping in the ceramics. Temperature-dependent XEL measurements imply that the green emission of the ceramic sample is always dominant with the increase of temperature from 77 K to 340 K, attributed to the cross-relaxation between 5D 3 and 5D 4 levels of Tb3+. • A new introducing method of Tb3+ doping was proposed to optimize the doping uniformity in water-bath method. • Gd 2 O 2 S:Tb nanopowders with good luminescent properties were synthesized by reducing the single-phase precursor. • This method is promising for the preparation of Gd 2 O 2 S ceramics with good scintillation properties. [ABSTRACT FROM AUTHOR]

Yb,La:CaF 2 nano-powders doped with different Yb3+ concentrations as 1, 2, 3, 5 at.% were synthesized by the co-precipitation method. The Yb,La:CaF 2 powders which were in pure cubic CaF 2 phase. The Yb,La:CaF 2 transparent ceramics were prepared by the air pre-sintering at different temperatures for 2 h with hot isostatic pressing (HIP) post-treatment at 650 °C for 2 h under 62 MPa Ar. The influences of the Yb3+ doping concentration and pre-sintering temperature on optical quality and microstructures of ceramics were investigated. Among all the fabricated ceramics, the 3 at.%La,5 at.%Yb:CaF 2 transparent ceramics pre-sintered at 650 °C showed the best optical quality. For the 1 mm thickness sample, its in-line transmittance reached 92.6% at 1200 nm. Furthermore, the absorption and the emission cross sections of the ceramics were calculated. The strongest absorption and emission peaks are around 977 nm. The lifetime for the Yb,La:CaF 2 transparent ceramics at 1028 nm increased first and then decreased with further increasing the Yb3+ doping concentrations. • Yb,La:CaF 2 transparent ceramics were prepared by the air pre-sintering and HIP post-treatment. • The role of the pre-sintering temperature and Yb concentration on the Yb,La:CaF 2 ceramics were studied. • In-line transmittance of the fabricated 5 at.%Yb,3 at.%La:CaF2 ceramics is 92.6% at 1200 nm. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we demonstrated the effect of crystal defects on the photoelectrochemical properties of ZnO nanorod arrays (NRAs). Vertically aligned ZnO NRAs with different defect contents were grown on F doped SnO2 (FTO) glass substrate via facile electrochemical process and annealing treatement. [Copyright &y& Elsevier]