[en] A series of white emitting phosphor of KMgLa (PO₄)₂:Dy³⁺ were synthesized via high temperature solid-state method, and the luminescence properties were systematically investigated. Under the 349 nm ultraviolet excitation, KMgLa(PO₄)₂:Dy³⁺ shows the 481 nm (blue) and 575 nm (yellow) emission peaks, which are assigned to the ⁴F_9/2–⁶H_15/2 and ⁴F_9/2–⁶H_13/2 transitions of Dy³⁺. The emission intensities of KMgLa(PO₄)₂:Dy³⁺ are influenced by the Dy³⁺ concentration, and the concentration quenching effect is observed, and the corresponding mechanism is the dipole–dipole (d–d) interaction, and the critical distance is calculated to be 1.136 nm. The CIE chromaticity coordinates of KMgLa(PO₄)₂:Dy³⁺ are close to that of standard white light. According to the emission intensity with different temperatures, the sample should have the good thermal stability. The results indicate that KMgLa(PO₄)₂:Dy³⁺ may be a potential application to white LEDs.

[en] Sm³⁺, Eu³⁺, and Sm³⁺–Eu³⁺ doped Ca₂PO₄Cl phosphors are synthesized by a solid-state method. Ca₂PO₄Cl:Sm³⁺ can produce red emission under the 400 nm radiation excitation, and the emission peak is located at 601 nm, which is assigned to the ⁴G_5/2→⁶H_7/2 transition of Sm³⁺. Ca₂PO₄Cl:Eu³⁺ can create red emission under the 392 nm radiation excitation, and the strongest peak is located at 620 nm, which is attributed to the ⁵D₀→⁷F₂ transition of Eu³⁺. The energy transfer from Sm³⁺ to Eu³⁺ in Ca₂PO₄Cl has been validated and the critical distance (R_c) of Sm³⁺ to Eu³⁺ in Ca₂PO₄Cl is calculated to be 1.14 nm. With increasing Eu³⁺ doping concentration, the energy transfer efficiency (Sm³⁺→Eu³⁺) gradually increases to 53.7%. The luminescence property of Ca₂PO₄Cl:Sm³⁺, Eu³⁺ can be tuned by properly tuning the relative ratio of Sm³⁺–Eu³⁺, and the emission intensity of Ca₂PO₄Cl:Eu³⁺ can be greatly enhanced by codoped Sm³⁺. - Highlights: • Ca₂PO₄Cl:Sm³⁺, Eu³⁺ can produce red emission under the 400 nm radiation excitation. • The energy transfer from Sm³⁺ to Eu³⁺ in Ca₂PO₄Cl has been validated. • The critical distance of Sm³⁺ to Eu³⁺ in Ca₂PO₄Cl is calculated to be 1.14 nm

[en] Graphical abstract: Under the 350 nm radiation excitation, Ba₂B₂O₅:Ce³⁺ has a broad blue emission band. When the temperature turned up to 150 °C, the emission intensity of Ba_1.97B₂O₅:0.03Ce³⁺ is 63.4% of the initial value at room temperature. The activation energy ΔE is calculated to be 0.25 eV, which prove the good thermal stability of Ba₂B₂O₅:Ce³⁺. All the properties indicate that Ba₂B₂O₅:Ce³⁺ may have potential application in white LEDs. - Highlights: • Ba₂B₂O₅:Ce³⁺ has a broad blue emission band under the 350 nm radiation excitation. • Emission intensity of Ba₂B₂O₅:Ce³⁺ is 63.4% (150 °C) of the initial value (30 °C). • The activation energy ΔE for thermal quenching is 0.25 eV. - Abstract: A novel blue emitting phosphor Ba₂B₂O₅:Ce³⁺ is synthesized by a high temperature solid state method. The luminescent property and the thermal stability of Ba₂B₂O₅:Ce³⁺ are investigated. Under the 350 nm radiation excitation, Ba₂B₂O₅:Ce³⁺ has a broad blue emission band, and the peak locates at 417 nm which is assigned to the 5d¹–4f¹ transition of Ce³⁺. It is further proved that the dipole–dipole interaction results in the concentration quenching of Ce³⁺ in Ba₂B₂O₅:Ce³⁺. When the temperature turned up to 150 °C, the emission intensity of Ba_1.97B₂O₅:0.03Ce³⁺ is 63.4% of the initial value at room temperature. The activation energy ΔE is calculated to be 0.25 eV, which prove the good thermal stability of Ba₂B₂O₅:Ce³⁺. All the properties indicate that Ba₂B₂O₅:Ce³⁺ may have potential application in white LEDs

[en] A novel green phosphor SrZn_2(PO_4)_2:Tb"3"+ is synthesized by a high temperature solid-state method, and its luminescent property is investigated. X-ray diffraction patterns of SrZn_2(PO_4)_2:Tb"3"+ indicate a similarity crystalline phase to SrZn_2(PO_4)_2. SrZn_2(PO_4)_2:Tb"3"+ shows green emission under 369 nm excitation, and the prominent luminescence in green (544 nm) due to "5D_4–"7F_5 transition of Tb"3"+. For the 544 nm emission, excitation spectrum has several excitation band from 200 nm to 400 nm. Emission intensity of SrZn_2(PO_4)_2:Tb"3"+ is influenced by Tb"3"+ concentration, and concentration quenching effect of Tb"3"+ in SrZn_2(PO_4)_2 is also observed. With incorporating A"+ (A=Li, Na, and K) as compensator charge, the emission intensity of SrZn_2(PO_4)_2:Tb"3"+ can be obviously enhanced. CIE color coordinates of SrZn_2(PO_4)_2:Tb"3"+ locate in the green region. The results indicate this phosphor may be a potential application in white LEDs. - Graphical abstract: SrZn_2(PO_4)_2:Tb"3"+ can produce green emission under near-UV excitation, and its luminescent properties can be improved by incorporating A"+ (A=Li, Na, and K). - Highlights: • SrZn_2(PO_4)_2:Tb"3"+ can produce green emission under near-UV excitation. • Concentration quenching effect of Tb"3"+ in SrZn_2(PO_4)_2 is observed. • Emission intensities of SrZn_2(PO_4)_2:Tb"3"+ are enhanced by codoped A"+ (A=Li, Na, K)

[en] This paper synthesizes the Sr₂SiO₄ : Eu²⁺ phosphor by high temperature solid-state reaction. The emission spectrum of Sr₂SiO₄ : Eu²⁺ shows two bands centred at 480 and 547 nm, which agree well with the calculation values of emission spectrum, and the location of yellow emission of Sr₂SiO₄ : Eu²⁺ is influenced by the Eu²⁺ concentration. The excitation spectrum for 547nm emission has two bands at 363 and 402 nm. The emission spectrum of white light emitting diodes (w-LEDs) based on Sr₂SiO₄ :Eu²⁺ phosphor + InGaN LED was investigated

[en] Na₃Bi(PO₄)₂:Eu³⁺/Tb³⁺/Dy³⁺/Sm³⁺ phosphors were synthesized via a high-temperature solid-state reaction method. The X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), diffuse reflection, photoluminescence (PL) and fluorescent decay curves were utilized to characterize the obtained phosphors. Under n-UV excitation, Na₃Bi(PO₄)₂:Eu³⁺/Tb³⁺/Dy³⁺/Sm³⁺ samples show the characteristic f-f emissions and present red, green, yellow and orange emission, respectively. When Tb³⁺, Dy³⁺ and Sm³⁺ were co-doped into the Na₃Bi(PO₄)₂:Eu³⁺ phosphors, tunable emission colors can be obtained and can be efficiently adjusted by varying the doping ions and the doping concentration. The energy transfer mechanisms were investigated in detail and demonstrated that there is an efficient energy transfer from Tb³⁺, Dy³⁺ and Sm³⁺ to Eu³⁺ via a dipole-dipole interaction mechanism. Additional, as the temperature increases from RT to 150 °C, the PL intensity of Tb³⁺-Eu³⁺, Dy³⁺-Eu³⁺ and Sm³⁺-Eu³⁺ co-doped phosphors decreased to 86%, 85% and 88%, respectively, which prove good thermal stability. All the CIE coordinates of as-prepared phosphors are displayed and show abundant colors, making these materials have potential applications for n-UV-excited white-LEDs.

[en] Highlights: • This work designs a kind of phosphor, which is the single host doped single activated ion, with multiple emission. • The special garnet structure is selected in which only Mn²⁺ is doped, to obtain green, red and deep red emission spectra. • A full-spectrum plant growth LED phosphor excited by blue light is obtained, which emission covers 500 nm to 850 nm. Full-spectrum plant growth light emitting diode (LED) prepared using a variety of phosphors has some problems, such as energy loss and spectral distortion. It is the solution that designing a kind of phosphor, which is the single activated ion doped phosphor with the multiple emission. To achieve this goal, the host Mg₂Y₂Al₂Si₂O₁₂ (Abbreviated as: MYASO) was selected from a large number of garnet materials which has the multi-sites, and the Mn²⁺ was selected as the activated ion which can produce the different emission in the different crystal field. The results show that Mn²⁺ can produce the green light (536 nm), red light (635 nm) and deep red light (735 nm), which correspond to the Mn²⁺ substituting for the tetra-coordinated Al³⁺, the octa-coordinated Mg²⁺ and the hexa-coordinated Mg²⁺, respectively, importantly, this phosphor can be efficiently excited by the 456 nm blue light, which matches well with the blue LED chip. Therefore, it may be a great potential application value in the production of plant growth LEDs.

[en] A series of Dy³⁺, Ce³⁺/Dy³⁺, Eu²⁺/Dy³⁺ and Ce³⁺/Eu²⁺/Dy³⁺ doping LiBaB₉O₁₅ (LBB) phosphors were synthesized via a high temperature solid-state method. LBB:Dy³⁺ cannot create light under ultraviolet radiation, however, LBB:Ce³⁺, Dy³⁺ can produce yellow emission under 295 nm excitation. The energy transfer occurs from Ce³⁺ to Dy³⁺ ions via electric dipole-dipole interaction and the critical distance is estimated to be 21.15 Å based on concentration quenching model. Generally, Eu²⁺ ion is a sensitizer to Dy³⁺ ion, however, there is only the emission of Eu²⁺ in LBB:Eu²⁺, Dy³⁺, which means there is no energy transfer from Eu²⁺ to Dy³⁺ ions. Interestingly enough, when doping Eu²⁺ ion into LBB:Ce³⁺, Dy³⁺, white emission can be achieved by increase the blue (350–425 nm) emission intensity. The spectral property, quantum efficiency, CIE chromaticity coordinates and thermal quenching property of LBB:Ce³⁺, Eu²⁺, Dy³⁺ are investigated. The results indicate that LBB:Ce³⁺, Eu²⁺, Dy³⁺ may be a potential application to white light emitting diodes. - Graphical abstract: LBB:Ce³⁺, Dy³⁺ can create white emission by doping Eu²⁺ ions. - Highlights: • LBB:Ce³⁺, Dy³⁺ can produce white emission by doping Eu²⁺ ion. • There is no energy transfer from Eu²⁺ to Dy³⁺ ions. • Energy transfer occurs from Ce³⁺ to Dy³⁺ ions. • LBB:Ce³⁺, Eu²⁺, Dy³⁺ may be a potential application for white LEDs.

[en] In this paper, the Sr₃Y₂(BO₃)₄:Eu³⁺ phosphor was synthesized by high temperature solid-state reaction method and the luminescence characteristics were investigated. The emission spectrum exhibits one strong red emission at 613 nm corresponding to the electric dipole ⁵D₀–⁷F₂ transition of Eu³⁺ under 365nm excitation, this is because Eu³⁺ substituted for Y³⁺ occupied the non-centrosymmetric position in the crystal structure of Sr₃Y₂(BO₃)₄. The excitation spectrum indicates that the phosphor can be effectively excited by ultraviolet (254 nm, 365nm and 400 nm) and blue (470 nm) light. The effect of Eu³⁺ concentration on the red emission of Sr₃Y₂(BO₃)₄:Eu³⁺ was measured, the result shows that the emission intensities increase with increasing Eu³⁺ concentration, then decrease. The Commission Internationale del'Eclairage chromaticity (x, y) of Sr₃Y₂(BO₃)₄: Eu³⁺ phosphor is (0.640, 0.355) at 15 mol% Eu³⁺

[en] Highlights: • Long afterglow of Zn₃Al₂Ge₂O₁₀:Cr³⁺ was caused by introducing Ca²⁺. • Bluish white emission of Zn₃Al₂Ge₂O₁₀:Cr³⁺ was created by introducing Ca²⁺. • Zn₃Al₂Ge₂O₁₀:Cr³⁺ can produce red emission in the range of 650–750 nm. The long afterglow and bluish white emission of red emitting material Zn₃Al₂Ge₂O₁₀:Cr³⁺ are induced by introducing Ca²⁺. Under excitation of 400 nm, Zn₃Al₂Ge₂O₁₀:Cr³⁺ can emit a red emission band at 694 nm in the range of 650–750 nm that is caused by ²E → ⁴A₂ transition of Cr³⁺. Under 262 nm excitation, Zn₃Al₂Ge₂O₁₀:Cr³⁺ can produce a weakly broad emission band in the range of 350–600 nm, and the emission intensity of Zn₃Al₂Ge₂O₁₀:Cr³⁺ can be enhanced by tuning the ratio of Ca²⁺ to Zn²⁺, especially, Zn₃Al₂Ge₂O₁₀:Cr³⁺ can present a bluish white emission and long afterglow properties by introducing Ca²⁺. The bluish white luminescence is caused by increasing the intrinsic defects (V^ʺ_Zn, V^ʺ_Ca and V^ʺ_O). And Ca vacancies can assist to stabilize the O vacancies; therefore, Zn₃Al₂Ge₂O₁₀:Cr³⁺ show the long afterglow characteristics. It enriched the luminescent properties of Zn₃Al₂Ge₂O₁₀:Cr³⁺ by introducing Ca²⁺, since Zn₃Al₂Ge₂O₁₀:Cr³⁺ shows different characteristics under different radiation excitation.