M2(Si,Al)4(N,C)7 (M = La,Y,Ca) carbonitrides

Liddell, K.; Thompson, D. P.; Teat, Simon J.

doi:10.1016/j.jeurceramsoc.2004.03.008

Cited by 17 publications

(21 citation statements)

References 9 publications

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“…The related Y 2 Si 4 N 6 C (2461)-type structure has monoclinic P2 1 /c symmetry with C substituted only at the 4-connected positions to give C(SiN 3 ) 4 units. [17][18][19] The 5-coordinate Y1 and 6-coordinate Y2 sites are derived from the Y and Sr sites respectively in the SrYSi 4 N 7 type. Photoluminescence properties of doped SrYSi 4 N 7 and Y 2 Si 4 N 6 C types have previously been reported.…”

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confidence: 99%

“…[19] Several studies have proposed that higher covalence is expected in the Y 2 Si 4 N 6 C network owing to the introduction of carbon, so that the thermal stability of photoluminescence in carbidonitridosilicates is expected to be better than that of corresponding SrYSi 4 N 7 type nitrides. [17,20,21] However, no studies of the evolution of phosphor properties within is surprising, as the progressive replacement of Sr 2+ and N 3− by Y 3+ and C 4− was expected to introduce more covalency into the materials and hence raise lattice rigidity and the quenching barrier height. [21,22] We propose that this reveals a dominant neighboring-cation influence as follows.…”

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Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

et al. 2013

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Blue, green, and yellow phosphors are obtained in the Sr1−xY0.98+xCe0.02Si4N7−xCx system (x=0→1). Decreases in thermal quenching barrier height with x result from a dominant neighboring‐cation effect, through which the replacement of Sr2+ by Y3+ reduces the covalency of CeN bonding. Green emission is observed from a cation‐segregated nanostructure of SrYSi4N7 and Y2Si4N6C domains in x=0.2–0.6 samples.

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Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

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“…[17][18][19] The 5-coordinate Y1 and 6-coordinate Y2 sites are derived from the Y and Sr sites respectively in the SrYSi 4 N 7 type. [17][18][19] The 5-coordinate Y1 and 6-coordinate Y2 sites are derived from the Y and Sr sites respectively in the SrYSi 4 N 7 type.…”

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“…[14,15,18,19] Eu 2+ -and Ce 3+ -doped SrYSi 4 N 7 respectively emit 548-570 nm yellow light and 450 nm blue light when excited at 390 nm. [17,20,21] However, no studies of the evolution of phosphor properties within Sr 1Ày Y 1+y Si 4 N 7Ày C y hosts have been reported. [19] Several studies have proposed that higher covalence is expected in the Y 2 Si 4 N 6 C network owing to the introduction of carbon, so that the thermal stability of photoluminescence in carbidonitridosilicates is expected to be better than that of corresponding SrYSi 4 N 7 type nitrides.…”

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Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

et al. 2013

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Phosphor materials play a key role in white-light emitting diode (LED) devices based on gallium indium nitride (GaInN). [1][2][3][4][5] Phosphors for white LEDs should have good thermal stability and conversion efficiency and an excitation wavelength range in the UV to blue region (370-460 nm). [3,[6][7][8] The yellow-emitting phosphor (Y,Gd) 3 (Al,Ga) 5 O 12 :Ce 3+ is a well-known commercial example, but the lack of red emission results in cold white light and a low color-rendering index (CRI). [1,7,9,10] Nitride-based materials are more covalent than oxides, which improves thermal stability, and their greater crystal field splitting increases the red emission leading to warmer white light. [1,2,11,12] The chemistry of doped nitride phosphors is often complex and it may be difficult to understand how substitutions tune photoluminescence properties, as the local environment of activator ions may be quite different to the structural average. For example, local O/N ordering driven by the size mismatch between the Eu 2+ activator and the host cations was found to be an important effect in M 1.95 Eu 0.05 Si 5Àx Al x O 8Àx N x (M = Ca, Sr, Ba) phosphors. [12] Herein we demonstrate a new approach to controlling phosphor properties through segregation of activator cations on the nanoscale, as applied to Sr 1Àx Y 0.98+x Ce 0.02 Si 4 N 7Àx C x carbidonitridosilicate phosphors, and we show that overall trends evidence a significant neighboring-cation influence.Two structure types are encountered in the studied system. The SrYSi 4 N 7 (1147) type structure with hexagonal (space group P6 3 mc) symmetry contains a network of cornerlinked N(SiN 3 ) 4 structural units. [13][14][15][16] Sr and Y sites are coordinated by 12 and 6 nitrides, respectively. The related

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Missing Member in the M^IIM^IIISi₄N₇ Compound Class: Carbothermal Reduction and Nitridation Synthesis Reveal Substitution of Nitrogen by Carbon and Oxygen in CaLu[Si₄N_7–2xC_xO_x]:Eu²⁺/Ce³⁺ (x≈0.3)

Gamperl

Zeman

Strobel

et al. 2021

Chemistry A European J

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The nitridosilicate CaLu[Si 4 N 7-2x C x O x ] (x � 0.3) was synthesized by carbothermal reduction and nitridation starting from CaH 2 , Lu 2 O 3 , graphite and amorphous Si 3 N 4 at 1550 °C in a radiofrequency furnace. CaLu[Si 4 N 7-2x C x O x ] (x � 0.3) crystallizes isotypically to many previously known M II M III Si 4 N 7 compounds in the space group P6 3 mc, as was confirmed by Rietveld refinement based on powder X-ray diffraction data. Incorporation of carbon into the crystal structure as a result of the carbothermal synthesis route was confirmed by 13 C and 29 Si MAS NMR spectroscopy. For the first time in the M II M III Si 4 N 7 compound class, complementary EDX measurements suggest that simultaneous incorporation of oxygen compensates for the negative charge excess induced by carbon, resulting in an adjusted sum formula, CaLu[Si 43) shows an emission maximum in the blue spectral region (λ em = 484 nm; fwhm = 4531 cm À 1 ) upon doping with Ce 3 + , whereas Eu 2 + -doped CaLu[Si 4 N 7-2x C x O x ] (x � 0.3) exhibits a yellow-green emission (λ em = 546 nm; fwhm = 3999 cm À 1 ).

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M2(Si,Al)4(N,C)7 (M = La,Y,Ca) carbonitrides

Cited by 17 publications

References 9 publications

Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

Missing Member in the M^IIM^IIISi₄N₇ Compound Class: Carbothermal Reduction and Nitridation Synthesis Reveal Substitution of Nitrogen by Carbon and Oxygen in CaLu[Si₄N_7–2xC_xO_x]:Eu²⁺/Ce³⁺ (x≈0.3)

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M2(Si,Al)4(N,C)7 (M = La,Y,Ca) carbonitrides

Cited by 17 publications

References 9 publications

Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

Nanosegregation and Neighbor‐Cation Control of Photoluminescence in Carbidonitridosilicate Phosphors

Missing Member in the MIIMIIISi4N7 Compound Class: Carbothermal Reduction and Nitridation Synthesis Reveal Substitution of Nitrogen by Carbon and Oxygen in CaLu[Si4N7–2xCxOx]:Eu2+/Ce3+ (x≈0.3)

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Missing Member in the M^IIM^IIISi₄N₇ Compound Class: Carbothermal Reduction and Nitridation Synthesis Reveal Substitution of Nitrogen by Carbon and Oxygen in CaLu[Si₄N_7–2xC_xO_x]:Eu²⁺/Ce³⁺ (x≈0.3)