Synthesis and luminescence properties of Mn4+-dopant Ca14Zn6Ga10?xAlxO35 solid solution

Mn~(4+)-activated oxide phosphors,owing to their desirable spectral features,eco-friendly and low cost,are emerging as a new class of non-rare-earth red phosphors for warm white LEDs.However,these phosphors possess low photoluminescence quantum efficiency excited by blue chip currently.Herein we report an isostructural solid solution of Ca_(14)Zn_6Ga_(10-x)Al_xO_(35):0.15Mn~(4+)(0≤x≤10)synthesized by a traditional solidstate reaction route.The microstructure and luminescent performance of this red-emitting phosphor are investigated in detail with the aids of X-ray diffraction,diffuse reflection spectra,photoluminescence spectra/decay/QE,and temperature-dependent PL/QE measurements.Blue shift of energy peaks of~4A_2→~4T_1and~4A_2→~4T_2transition is illustrated by the Tanabe–Sugano diagram and the configurational coordinate diagram.The crystal field strength(Dq)and the Racah parameters(B and C)are carefully calculated to estimate the nephelauxetic effectβrespectively.Particularly we achieve external and internal quantum efficiencies as high as26.1%and 40.3%for Ca_(14)Zn_6Ga_6Al_4O_(35):0.15Mn~(4+)excited by 466 nm,the highest one ever reported in Mn~(4+)activated oxide phosphors under the similar condition.

Synthesis and luminescence properties of Mn4+-dopant Ca14Zn6Ga10?xAlxO35 solid solution

Mn⁴⁺-activated oxide phosphors, owing to their desirable spectral features, eco-friendly and low cost, are emerging as a new class of non-rare-earth red phosphors for warm white LEDs. However, these phosphors possess low photoluminescence quantum efficiency excited by blue chip currently. Herein we report an isostructural solid solution of Ca₁₄Zn₆Ga_10?xAl_xO₃₅: 0.15Mn⁴⁺ (0 ≤ x ≤ 10) synthesized by a traditional solid-state reaction route. The microstructure and luminescent performance of this red-emitting phosphor are investigated in detail with the aids of X-ray diffraction, diffuse reflection spectra, photoluminescence spectra/decay/QE, and temperature-dependent PL/QE measurements. Blue shift of energy peaks of ⁴A₂ → ⁴T₁ and ⁴A₂ → ⁴T₂ transition is illustrated by the Tanabe–Sugano diagram and the configurational coordinate diagram. The crystal field strength (Dq) and the Racah parameters (B and C) are carefully calculated to estimate the nephelauxetic effect β respectively. Particularly we achieve external and internal quantum efficiencies as high as 26.1% and 40.3% for Ca₁₄Zn₆Ga₆Al₄O₃₅: 0.15Mn⁴⁺ excited by 466?nm, the highest one ever reported in Mn⁴⁺ activated oxide phosphors under the similar condition.