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Double-perovskite materials La1−xPrxBaCo2O5+δ (LPBCO), suitable for the application of intermediate-temperature solid oxide fuel cell (IT-SOFC) and other electrochemical devices, were successfully prepared through solid-state reaction method. The effects of La and Pr doping ratios on the crystallographic structure, thermochemical stability, thermal expansion, electrical conductivity, and electrochemical polarizations were analyzed and discussed. The X-ray diffraction results show that the crystal structure changes from single perovskite to double perovskite with the increase in Pr doping content. LPBCOs present excellent chemical stability with conventional electrolyte GDC at less than 1100 °C. The thermal expansion can be effectively reduced upon doping of Pr. The materials demonstrate high electrical conductivity even under relatively low temperatures, i.e., LP-73 (x = 0.3 with single perovskite) has the highest conductivity at 1680 S/cm at 400 °C. Among the double-perovskite compositions, LP-55 presents the highest performance in electrical conductivity though. Analysis of the electrochemical impedance spectra of LPBCOs symmetric cells reveals low area specific polarization resistances for these double-lanthanide-doped double-perovskite materials, and the charge transfer is determined as the dominating sub-process for the oxygen transport through the materials. All the findings show that La1−xPrxBaCo2O5+δ possesses excellent oxygen reduction activity and is promising for the application in IT-SOFCs. [ABSTRACT FROM AUTHOR]

Er3+-doped germanate glasses with superior thermal stability were prepared. Judd-Ofelt intensity parameters and important spectroscopic properties were discussed in detail. Upon 800 nm and 980 nm LD pumping, 2.7 µm fluorescence characteristics were investigated and it was found that the effective 2.7 µm emission bandwidth can reach to 101.79 nm in prepared glasses. The tunability of the 2.7 µm emission band can be realized by adjusting the Er3+ content. Moreover, a high-emission cross-section (11.09 ×10-21 cm2), large gain bandwidth (772.30 ×10-28 cm3) and gain coefficient (6.72 cm-1) were obtained in the prepared sample. Hence, Er3+-doped germanate glass might be a promising mid-infrared material for tunable amplifiers or lasers. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] A kind of novel FP glass is prepared. [•] The structure evolution caused by Yb3+ has been investigated. [•] The near-infrared luminescence properties evolution caused by Yb3+ has been investigated. [•] The quenching concentration of Yb3+ as the sensitizer is found in prepared system. [•] The novel FP glass has good spectroscopic properties. [Copyright &y& Elsevier]

Abstract: In this paper, new Ho3+/Yb3+ co-doped fluorophosphate glasses with superior thermal stability against crystallization have been synthesized. Intense 2μm emissions have been observed when pumped by a conventional 980nm laser diode. High infrared transmittance (82%) and low hydroxyl concentration (16.7ppm) can be realized according to the analysis of infrared transmittance spectrum. Based on the measured absorption spectra, a thorough calculation of the Judd–Ofelt parameters and radiative properties has been carried out. The predicted spontaneous transition probability, emission cross section and gain coefficient of Ho3+:5I7→5I8 can reach to 74.11s−1, 4.53×10−21 cm2, and 0.8cm−1, respectively. Besides, the energy transfer coefficients from Yb3+ to Ho3+ have also been calculated and discussed. The results suggest the prepared glass is a good candidate for efficient 2μm laser. [Copyright &y& Elsevier]

Highlights: [•] Er3+ doped Y2O3 and Nb2O5 modified germanate glasses were prepared. [•] Spectroscopic properties and energy transfer mechanism were studied. [•] Non-radiative relaxation rates and energy transfer microparameters were calculated. [•] The prepared samples have potential applications in mid-infrared lasers. [ABSTRACT FROM AUTHOR]

Highlights: [•] Er3+ doped and Er3+/Ce3+ co-doped silica–germanate glasses are fabricated. [•] The thermal stability and spectra properties are investigated. [•] The FWHM of Er3+/Ce3+-codoped silica–germanate glass reaches 108nm. [•] The stimulated emission cross-sections are calculated and discussed. [•] The gain spectra of prepared samples are also investigated. [ABSTRACT FROM AUTHOR]

Abstract: Intense 2.7 μm emission derived from modified Er3+ doped germanate glass was reported. Raman spectrum analysis was carried out to grasp glass structure. Based on the absorption spectrum, the Judd–Ofelt parameters and radiative properties were calculated originated from Judd–Ofelt theory. 2.7 μm emission characteristics, stark splitting features and energy transfer processes upon excitation of a conventional 808 nm or 980 nm laser diode were carefully investigated. The prepared glass possesses high spontaneous transition probability (34.28 s−1), large calculated emission cross section (13 × 10−21 cm2) and gain coefficient (5.4 cm−1) for the 4I11/2 → 4I13/2 transition. These results indicate that Er3+ doped germanate glass has potential applications in mid-infrared lasers and amplifiers. [Copyright &y& Elsevier]

In this paper, a new type of germa-silicate glass was developed. A detailed investigation of thermal stability, absorption spectrum and 1.53μm emission spectrum was carried out. Based on the absorption spectrum and Judd–Ofelt theory, the Judd–Ofelt parameters and radiative properties were calculated and compared to other glasses. The thermal stability of prepared glass can reach as high as 155°C. Er3+ doped germa-silicate glass possessing high full-width at half-maximum (FWHM) (77nm) and large stimulated emission cross-section (9.55×10−21 cm2) shows its potential application in broadband optical amplifier. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, Er3+ doped Y2O3 and Nb2O5 modified germanate glasses possessing good thermal stability are reported. On the basis of absorption spectra and Judd–Ofelt theory, a detailed investigation of Judd–Ofelt intensity parameters (Ω 2,4,6) and radiative properties is carried out. Moreover, emission cross section at 2.7μm is calculated based on Füchtbauer–Ladenburg equation and compared with other Er3+ doped glass systems. A reasonable energy transfer mechanism is proposed. It is interesting that the emission cross section and radiative transition probability in 5mol% Nb2O5 modified germanate glass are much larger than those with 5mol% Y2O3. Results indicate that present germanate glasses along with excellent 2.7μm spectroscopic performance might have potential application for mid-infrared fiber laser. [Copyright &y& Elsevier]

Er3+ doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Ωt (t = 2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s−1), emission cross section σem (10.18 × 10−21 cm2) and σem × Δλeff (945.32 × 10−28 cm3), corresponding to the 2.7 μm emission of Er3+: 4I11/2→ 4I13/2 transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er3+ concentration. The calculation results show that with the increment of Er3+ concentration, the energy transfer up-conversion rate of 4I13/2 state increases while the rate of 4I11/2 state reduces, resulting in the change of 2.7 μm emission. [ABSTRACT FROM AUTHOR]

Highlights: [•] Novel Er3+ doped germanosilicate glasses were synthesized. [•] Excellent thermal stability and 2.7μm emission properties were obtained. [•] High A rad (33.75s−1) and emission cross section (1.90×10−20 cm2) were achieved. [•] A reasonable energy transfer mechanism was put forward. [ABSTRACT FROM AUTHOR]

Er(3+) -doped germanate glasses with superior thermal stability were prepared. Judd-Ofelt intensity parameters and important spectroscopic properties were discussed in detail. Upon 800 nm and 980 nm LD pumping, 2.7 µm fluorescence characteristics were investigated and it was found that the effective 2.7 µm emission bandwidth can reach to 101.79 nm in prepared glasses. The tunability of the 2.7 µm emission band can be realized by adjusting the Er(3+) content. Moreover, a high-emission cross-section (11.09 × 10(-21) cm(2) ), large gain bandwidth (772.30 × 10(-28) cm(3) ) and gain coefficient (6.72 cm(-1) ) were obtained in the prepared sample. Hence, Er(3+) -doped germanate glass might be a promising mid-infrared material for tunable amplifiers or lasers., (Copyright © 2014 John Wiley & Sons, Ltd.)