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Ca [1−3x/2] TiO 3 :xSm 3+ (0 ≤ x ≤ 5 mol%), Ca 0.955 TiO 3 :0.03Sm 3+ + 10 mol% H 3 BO 3 , Ca 0.94 TiO 3 :0.03Sm 3+ , 0.03Na + phosphors are synthesized by high temperature solid–state reaction method in air. All samples are pure phase CaTiO 3 . Two strong excitation bands within the range 400–435 nm and 455–510 nm are observed, which are nicely match with widely applied near-UV (400–430 nm) and blue (460–500 nm) LED chips. The strongest emission band peaking at ∼603 nm is assigned to the 4 G 5/2 → 6 H 7/2 transition of Sm 3+ ion. The optimal Sm 3+ doping concentration is ∼3 mol%. Fluorescent lifetimes of Ca 0.955 TiO 3 :0.03Sm 3+ phosphor with excitation 408, 467, and 481 nm are ∼0.809 m, 0.792 m, and 0.8 m, respectively. The PL intensity of Ca 0.955 TiO 3 :0.03Sm 3+ phosphor is enhanced 5–7 times after Na + ion is codoped as charge compensator and H 3 BO 3 is added as flux, and their CIE chromaticity coordinate is ∼ (0.5792, 0.4199). The experiment results are helpful to improve luminescence properties of other Sm 3+ -doped phosphors and study novel phosphors. [ABSTRACT FROM AUTHOR]

Li5La3Ta2O12:Mn4+ (LLTO:Mn4+) phosphors are prepared in air via high‐temperature solid‐state method and investigated for their crystal structures and luminescence properties. LLTO:Mn4+ phosphor under excitation at 314 nm shows deep‐red emission peaking at 714 nm due to the 2E→4A2 transition of Mn4+ ion. The excitation bands in the range 220 ‐ 570 nm are attributed to the Mn4+ ‐ O2‐ charge‐transfer band and the 4A2g→4T1g, 2T2g, and 4T2g transitions of Mn4+, respectively. The optimal Mn4+ ion concentration is ~0.4 mol%. The concentration quenching mechanism in LLTO:Mn4+ phosphor is electric dipole‐dipole interaction. The luminous mechanism and temperature quenching phenomenon are explained by the Tanabe‐Sugano energy level diagram and the configurational coordinate diagram of Mn4+ in the octahedron, respectively. The experimental results indicate that LLTO:Mn4+ phosphor has a potential application prospect as candidate of deep‐red component in light‐emitting diode (LED) lighting. [ABSTRACT FROM AUTHOR]

Li 2 Mg 3 SnO 6 :Mn 4+ deep red phosphor is synthesized by high-temperature solid-state reaction method in air. With excitation 330 and 480 nm, the emission band peaking at ∼670 nm within the range 600–790 nm is observed owing to the 2 E → 4 A 2 transition of Mn 4+ ion. Excitation bands peaking at ∼330, 395, and 480 nm in the range of 220–600 nm indicate that Li 2 Mg 3 SnO 6 :Mn 4+ phosphor can be effectively excited by (near) ultraviolet and blue light-emitting diode chips. The optimal Mn 4+ ion concentration is ∼0.4 mol%. Fluorescence lifetime and quantum efficiency of Li 2 Mg 3 SnO 6 :0.4%Mn 4+ phosphor with excitation 330 nm are ∼266.67 μs and 36.3%, respectively. The luminous mechanism is explained by the Tanabe-Sugano energy level diagram of Mn 4+ in the octahedron. [ABSTRACT FROM AUTHOR]

Host SrSb 2 O 6 , SrSb 2 O 6 :Bi 3 + , SrSb 2 O 6 :Eu 3 + , and SrSb 2 O 6 :Eu 3 + , Bi 3 + phosphors are synthesized by solid state reaction method in air. Host SrSb 2 O 6 with excitation 254 nm shows weak green-yellow emission in the range of 320–780 nm due to Sb 5 + → O 2– transition. SrSb 2 O 6 :Bi 3 + phosphor with excitation 365 nm emits green light within the range 400–650 nm owing to the 3 P 1 → 1 S 0 transition of Bi 3 + ion. SrSb 2 O 6 :Eu 3 + phosphor with excitation 254 nm exhibits a systematically varied hue from green to orange-red light by increasing Eu 3 + concentration from 0 to 7 mol%, and that with excitation 394 nm only shows orange-red light. The optimal Eu 3 + concentration is ~ 4 mol% in SrSb 2 O 6 :Eu 3 + phosphor. SrSb 2 O 6 :Eu 3 + , Bi 3 + phosphor with excitation 254 and 394 nm emits orange-red light. Emission intensity of SrSb 2 O 6 :Eu 3 + phosphor may be enhanced > 2 times by co-doping Bi 3 + ion because of the fluxing agent and energy transfer roles of Bi 3 + ion in SrSb 2 O 6 :Eu 3 + , Bi 3 + phosphor. The luminous mechanism of SrSb 2 O 6 :Eu 3 + , Bi 3 + phosphor is analyzed and explained by the simplified energy level diagrams of Sb 2 O 6 2 − group, Bi 3 + and Eu 3 + ions, and energy transfer processes between them. [ABSTRACT FROM AUTHOR]

A double perovskite Sr 2 ZnMoO 6 :Mn 4+ (SZM:Mn 4+ ) phosphor is synthesized by high-temperature solid-state reaction method in air. Emission band peaking at ∼705 nm of SZM:Mn 4+ phosphor in the range of 650–790 nm is attributed to the 2 E → 4 A 2 transition of Mn 4+ ion with activated different lattice vibration modes. Three excitation bands in the range of 210–610 nm are assigned to the O 2− → Mn 4+ charge transfer and the 4 A 2 → ( 4 T 1 , 2 T 2 , and 4 T 2 ) transition of Mn 4+ ion. The optimal Mn 4+ ion concentration is ∼0.8 mol% in SZM:Mn 4+ phosphor. Fluorescence lifetime of SZM:Mn 4+ phosphor decreases from ∼132 μs to 108 μs with increasing Mn 4+ ion concentration in the range of 0.2–1.0 mol%. Time-resolved spectra and fluorescence lifetime data indicate that luminescent center is caused by Mn 4+ ion. The luminous mechanism of SZM:Mn 4+ phosphor is explained by Tanabe-Sugano energy level diagram of Mn 4+ ion. The results are useful to understand the influences of the neighboring coordination environment around Mn 4+ and host crystal structure to the luminescence properties of Mn 4+ ion and develop other novel Mn 4+ -doped materials. [ABSTRACT FROM AUTHOR]

Novel double perovskite Li 3 Mg 2 NbO 6 :Mn 4+ deep red-emitting phosphor is synthesized by solid-state reaction method in air. Emission band peaking at ∼670 nm with chromaticity coordinates (0.722, 0.278) is observed in the range of 600–780 nm due to 2 E → 4 A 2 transition of Mn 4+ ion. Excitation spectrum monitored at 670 nm contains three excitation bands peaking at ∼310, 395, and 470 nm within the range 220–600 nm, which indicate that Li 3 Mg 2 NbO 6 :Mn 4+ phosphor can be excited by ultraviolet, near ultraviolet, and blue light-emitting diode chips. The optimal Mn 4+ doping concentration is about 0.4 mol%. Fluorescence lifetime decreases from 0.485 to 0.32 ms with increasing Mn 4+ ion concentration from 0.2 to 1.2 mol%. Time resolved emission spectra and lifetime data confirm that there is only a single type of Mn 4+ ion luminescent center in Li 3 Mg 2 NbO 6 :Mn 4+ phosphor. The possible luminous mechanism of Mn 4+ ion is analyzed by Tanabe–Sugano energy diagram. [ABSTRACT FROM AUTHOR]

Novel CaWO 4 :Eu 3+ , Mn 2+ red phosphor is synthesized by solid-state reaction method in air. CaWO 4 :Eu 3+ , Mn 2+ phosphor with excitation 268 and 394 nm emits red light with chromaticity coordinates (x = 0.6403, y = 0.3593). The strongest emission bands peaking at ∼615 nm is attributed to 5 D 0 → 7 F 2 of Eu 3+ ion. Strong excitation band peaking at ∼394 nm indicates that the phosphor may be excited by near UV (∼394 nm) chip. Emission intensity of CaWO 4 :Eu 3+ , Mn 2+ phosphor with excitation 268 nm is ∼2 times stronger than that of CaWO 4 :Eu 3+ phosphor owing to energy transfer between Eu 3+ ion and Mn 2+ ion. Energy transfer from WO 4 2 − group and Eu 3+ ion to Mn 2+ ion in CaWO 4 :Eu 3+ , Mn 2+ phosphor may be explained via luminescence properties. Luminous mechanism is analyzed by energy level diagrams of WO 4 2 − group, Mn 2+ and Eu 3+ ion. The paper content is helpful to develop and research other novel phosphors. [ABSTRACT FROM AUTHOR]