Narrow-band red emitting oxonitridosilicate phosphor La4-xSr2+xSi5N12-xOx:Pr3+ (x≈ 1.69)

Photoluminescence enhancement and excellent thermal stability of Ca2ZnSi2O7:Pr3+ red-emitting phosphors through charge compensator A+ (Li+, Na+ and K+) co-doping for w-LED applications

The red-emitting Ca2ZnSi2O7:Pr3+ phosphor was synthesized via a solid-state method and alkali metal ions A+ (Li+, Na+, K+) were introduced to improve the photoluminescence performance of Pr3+. XRD results confirmed that the sample structure did not change markedly with appropriate Pr3+/A+ co-doping. Under the blue light excitation of 447 nm, the as-prepared Ca2ZnSi2O7:Pr3+ efficiently emitted a characteristic red luminescence peak at 601 nm. The luminescence intensity of Pr3+ was obviously enhanced with A+ co-doping due to the charge compensation effect and the emission intensity of Ca2ZnSi2O7:0.005Pr3+, 0.005Na+ reached 142.1% compared to Ca2ZnSi2O7:0.005Pr3+. Furthermore, at 210 °C the luminescence intensity of the Ca2ZnSi2O7:0.005Pr3+, 0.005Na+ phosphor remained at ∼93% compared to at 30 °C, showing high thermal stability. The w-LED device packaged with Ca2ZnSi2O7:0.005Pr3+, 0.005Na+ produced a bright white emission. All these results indicated the potential application prospects of red-emitting Ca2ZnSi2O7:Pr3+, A+ phosphors in the field of white light-emitting diodes.

Zeolite-like Topology Oxonitridosilicate La3.6Ba1.7Si5N10O2.1 with Potential Applications in Nonlinear Optical Materials

A novel zeolite-like topology oxonitridosilicate La3.6Ba1.7Si5N10O2.1 with the space group Amm2 (no. 38) and lattice parameters a = 9.5193 (3) Å, b = 16.7011 (5) Å, c = 26.0279 (8) Å, and Z = 12 has been synthesized by a high-temperature solid-state reaction. The crystal structure of La3.6Ba1.7Si5N10O2.1 has four different kinds of tiling, and the cages in the structure are filled with La, Ba, and O atoms. The presence of a noncentrosymmetric space group further suggests its potential for nonlinear optical (NLO) applications, and La3.6Ba1.7Si5N10O2.1 demonstrated a stronger second-harmonic generation (SHG) response than that of SiO2.

Synthesis and Luminescence Properties of Amber Emitting La 7 Sr[Si 10 N 19 O 3 ] : Eu 2+ and Syntheses of the Substitutional Variants RE 8‐ x AE x [Si 10 N 20‐ x O 2+ x ] : Eu 2+ with RE =La, Ce; AE =Ca, Sr, Ba; 0≤ x ≤2

The oxonitridosilicate La₇Sr[Si₁₀N₁₉O₃] : Eu²⁺ and its substitutional variants RE_8‐xAE_x[Si₁₀N_20‐xO_2+x] : Eu²⁺ with RE=La, Ce; AE=Ca, Sr, Ba and 0≤x≤2 were synthesized starting from REN, SrN/Ca₃N₂/Ba₂N, SiO₂, amorphous Si₃N₄ and Eu₂O₃ as doping agent at 1600 °C in a radiofrequency furnace. The crystal structure of La₇Sr[Si₁₀N₁₉O₃] was solved and refined based on single‐crystal X‐ray diffraction data. La₇Sr[Si₁₀N₁₉O₃] crystallizes in the orthorhombic space group Pmn2₁ (no. 31). The crystal structures of the isotypic compounds RE_8‐xAE_x[Si₁₀N_20‐xO_2+x] were confirmed by Rietveld refinements based on powder X‐ray diffraction data using the single‐crystal data of La₇Sr[Si₁₀N₁₉O₃] as starting point. Crystal structure elucidation reveals a 3D network of vertex sharing SiN₄ and SiN₂(N_1/2‐x/4O_1/2+x/4)₂ (0≤x≤2) tetrahedra. When excited with UV to blue light, La₇Sr[Si₁₀N₁₉O₃] : Eu²⁺ shows amber luminescence with λ_em=612 nm and fwhm=84 nm/2194 cm⁻¹, which makes it interesting for application in amber phosphor‐converted light emitting diodes.

Enhanced luminescence performances of BaLaMgTaO6:Mn4+ red phosphor by Bi3+, Ca2+ doping for indoor plant lighting supplementary LED

A new perovskite BaLaMgTaO₆:Mn⁴⁺ (BLMTO:Mn⁴⁺) red phosphor was synthesized for the first time via the high-temperature solid-state method. The emission band of the phosphor ranges from 650 to 750 nm, which matches well with the absorption band of P_FR and P_R. By doping of Bi³⁺ and Ca²⁺ ions in the BLMTO:Mn⁴⁺ phosphor, a 4.76-fold enhancement in the luminescence emission intensity was achieved. The optimized BLMTO:0.5%Mn⁴⁺, 1.5%Bi³⁺, 2%Ca²⁺ phosphor exhibited a high quantum efficiency of 65% and a high color purity of 98.1% with the chromaticity coordinate (CIE) at (0.733, 0.267). Finally, a LED device was fabricated with the BLMTO:0.5%Mn⁴⁺, 1.5%Bi³⁺, 2%Ca²⁺ phosphor for further agricultural lighting, which emits warm white light with a low color temperature of 3549 K. The result indicates that the BLMTO:Mn⁴⁺, Bi³⁺, Ca²⁺ phosphors have a potential for applications in agricultural cultivations.

Synthesis and luminescence properties of new nitridolithosilicate phosphor La4Ba3Li3Si9N19: Pr3+ grown in Li flux

Flux synthesis is an effective method to discover large crystals of new compounds. In this paper, the solid-state reaction in Li flux produced a new nitridolithosilicate La4Ba3Li3Si9N19 in orthorhombic space...