On the synthesis and structure of LaCaGaO4

Zhaofei, LI; Li, Guobao; Liao, Fuhui; Lin, Jianhua

doi:10.1016/s0022-4596(02)00118-4

Cited by 6 publications

(3 citation statements)

References 37 publications

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“…Figure illustrates the evolution of the orthorhombic cell parameters with Ca and Sr content. For M‘ = Ca and x = 0.05, weak extra peaks corresponding to trace amounts of α-NdCaGaO 4 , , CaO and Ga 2 O 3 were observed, and the cell parameters are nearly identical (within three times the esd's) to those refined for x = 0.03. Similarly, for M‘ = Sr and x = 0.03, the cell parameters are nearly identical (within three times the esd's) to those refined for x = 0.015 and weak extra peaks corresponding to trace amounts of NdSrGaO 4 , SrO, and Ga 2 O 3 were observed.…”

Section: Resultsmentioning

confidence: 77%

Development of New Oxygen Ion Conductors Based on Nd₄GeO₈ and Nd₃GaO₆

et al. 2005

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New oxygen ion conductors have been prepared by substituting Ga3+ for Ge4+ in Nd4GeO8, Zn2+ and Mg2+ for Ga3+ in Nd3GaO6, and Ca2+ and Sr2+ for Nd3+ in Nd3GaO6. A combustion technique using ethylenediamine tetraacetic acid has been developed to synthesize these materials at ∼900 °C, leading to powders with spherical particles of about 100−200 nm. The green pellets obtained through the combustion-synthesized powders could be sintered to ∼98% at 1250 °C. It was found that Nd4Ge1 - x Ga x O8 - x /2 are formed up to x = 0.10, Nd3Ga1 - x M x O6 - x/2 (M = Zn, Mg) up to x = 0.03, and Nd3(1 - x)M‘3 x GaO6 - 3 x /2 up to x = 0.03 and 0.015 for M‘ = Ca and Sr, respectively. These relatively small substitution rates induce a significant increase in oxygen ion conductivity (σ800 ° C = 0.2 × 10-2 S cm-1 for Nd4Ge0.9Ga0.1O7.95; σ800 ° C = 0.5 × 10-2 and 0.4 × 10-2 S cm-1 for Nd3Ga0.97M0.03O5.985 with M = Zn and Mg, respectively, and σ800 ° C = 0.6 × 10-2 and 0.7 × 10-2 S cm-1 for Nd2.91Ca0.09GaO5.955 and Nd2.955Sr0.045GaO5.9775, respectively) with respect to pure Nd4GeO8 (σ800 ° C = 2.8 × 10-4 S cm-1) and pure Nd3GaO6 (σ800 ° C = 2.7 × 10-4 S cm-1).

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Section: Resultsmentioning

confidence: 77%

Development of New Oxygen Ion Conductors Based on Nd₄GeO₈ and Nd₃GaO₆

et al. 2005

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“…By indexing all peaks using orthogonal crystal cells ( Pnma ), it was found that the parameters were close to CaLaGaO 4 . [ 50 ] Consequently, this article used the structure of CaLaGaO 4 as the starting model for Rietveld refinement using TOPAS 4.2. The site of La 3+ ion was replaced by Gd 3+ and Refinements were stable.…”

Section: Resultsmentioning

confidence: 99%

Superior Quantum Efficiency Blue‐Emitting Phosphors with High Thermal Stability toward Multipurpose LED Applications

Gai,

Gao,

Chen

et al. 2024

Advanced Optical Materials

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Since Bi3+‐activated phosphor are widely reported in phosphors‐converted light‐emitting diodes (pc‐LEDs), developing new‐high efficiency phosphors is imperative. Herein, superior internal quantum efficiency (IQE = 93.7%) and external quantum efficiency (EQE = 70.5%) are achieved with blue‐emitting gallate phosphor CaGdGaO4:Bi3+. Particularly, the photoluminescence excitation (PLE) spectrum ranges from 200 to 400 nm with two peaks at 337 and 368 nm, which match well with the 365 nm near ultraviolet (n‐UV) chip. The blue emission is attributed to two luminescence centers caused by Bi3+ occupying GdO6 and CaO6 sites. Furthermore, the thermal stability (@ 150 °C) enhanced from 73.2% to 80.1% when Ca2+ doping. A white LED (WLED) with high color rendering index (Ra) of 93.8 is prepared by as‐synthesized phosphors, indicating the potential application in WLED. The blue and red dual‐emitting phosphors are achieved by co‐doping Bi3+ and Eu3+. Finally, the rice planting experiment presents that the blue‐emitting can efficiently enhance the photosynthesis and seeding index of rice, which indicated these phosphors have significance in plant fill light.

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“…However, when the sample was heated at higher temperature ($1350°C) and was subsequently air quenched to room temperature, a distorted form of K 2 NiF 4 structure type with I4mm space group was formed. In the latter variant, the gallium atoms deviate from the center of octahedra, which is the origin of ferroelectric property [11]. On the other hand, CaNdGaO 4 has been characterized with Cmca space group, where Ca 2+ and Nd 3+ ions are not ordered and are statistically distributed in crystal structure [12].…”

Section: Introductionmentioning

confidence: 99%