Novel red phosphor of Bi3+, Sm3+ co-activated NaEu(MoO4)2

Luminescence investigation of Eu3+ activated double molybdates red phosphors with scheelite structure

In the past decade, intensive research on proton-conducting oxide materials has provided a basis for the development of intermediate-temperature protonic ceramic electrochemical cells, which constitute a real alternative to conventional cells based on oxygen-conducting electrolytes. To achieve both high efficiency and excellent performance, not only electrolytes but also electrode materials should be carefully selected considering their functional properties. Compared to the traditional ABO3 perovskite electrode materials, Ln2NiO4+δ with a layered structure has unique advantages (high chemical stability, mechanical compatibility, improved oxygen transport, and hydration ability), and thus is now becoming a hot topic in this field, offering both scientific and practical interests. However, a comprehensive and in-depth review is still lacking in the literature to date. Accordingly, this work presents a comprehensive overview of the prospects of layered nickelates (Ln2NiO4+δ, where Ln = La, Nd, and Pr) as one of the most attractive oxygen (steam) electrode materials for protonic ceramic electrochemical cells. In particular, the crystalline features, defect structure, stability, chemical properties, and mechanical compatibility of this class of materials, contributing to their transport functionality, are discussed with the primary emphasis on revealing the relationship between the composition of the materials and their properties. The presented systematic results reveal the main strategies regarding the utilisation of Ln2NiO4+δ-based electrodes and existing gaps related to fundamental and applied research aspects.

Recent advances in layered Ln2NiO4+δ nickelates: fundamentals and prospects of their applications in protonic ceramic fuel and electrolysis cells

http://esl.ecsdl.org/content/8/4/H33.full.pdf

A Potential Red-Emitting Phosphor for LED Solid-State Lighting

Intense red phosphors, AgGd 0 . 9 5 Eu 0 . 0 5 (WO 4 ) 2 - x (MoO 4 ) x (x = 0 - 2) have been synthesized and characterized by powder X-ray diffraction (XRD) and photoluminescence. Powder XRD results reveal a phase transition from monoclinic to tetragonal structure at x ≥ 0.5. All compositions with Eu 3 + show red emission on excitation either in the charge-transfer band or Eu 3 + levels. Intense red emission is obtained in the molybdates, AgGd 0 . 0 5 Eu 0 . 0 5 (MoO 4 ) 2 under 465-nm excitation. Studies on AgGd 1 - y Eu y (WO 4 ) 2 and AgGd 1 - y Eu y (MoO 4 ) 2 (y = 0.1 - 1 in steps of 0.1) show that the emission intensity is maximum for compositions with y = 0.2 and 0.3, respectively, and a decrease in emission intensity is observed for higher y values. The intense red emission of the tungstate and molybdate phosphors under 394 and 465 nm excitation, respectively, suggests that these materials are promising candidates as red-emitting phosphors for near-UV/blue GaN-based light-emitting diodes for white light generation.

Intense Red-Emitting Phosphors for White Light Emitting Diodes

Structure and luminescent properties of three new silver lanthanide molybdates

Three new compounds, AgLnW
 2
O
 8

(Ln
 3+
=Eu, Gd or Tb), have been prepared by a solid-state
reaction and crystallize with a scheelite-related monoclinic symmetry.
Their IR spectra show absorption transitions in the region 1000–400
cm
 -1
 similar to KLnW
 2
O
 8
 . Broad
excitation and emission bands of the tungstate group with a large Stokes
shift (12 573 cm
 -1
) are observed in
AgGdW
 2
O
 8
 . Excitation and emission spectra of
AgLnW
 2
O
 8
 (Ln=Eu or Tb) show that energy transfer
from tungstate to Eu and Tb occurs and that Eu
 3+
 ions occupy a
unique crystallographic site with C
 2
 site
symmetry.

Yufang Ren

Papers

Structure and luminescent properties of three new silver lanthanide molybdates

Structure and luminescence properties of some new AgLnW 2 O 8 compounds

Preparation, structure and some physical properties of scheelite-related AgLnMo2O8 compounds

Preparation structure and physical properties of new silver lanthanide molybdenum oxides [AgLnMo2O8(Ln = La−Nd and Sm)]

Structure and physical properties of new phase oxide La2MoO5