pH dependent hydrothermal synthesis of Ca14Al10Zn6O35:0.15Mn4+ phosphor with enhanced photoluminescence performance and high thermal resistance for indoor plant growth lighting

Artificial light source for indoor cultivation has been vastly impeded by the lack of high far red emitting phosphors. Recently, Mn⁴⁺ activated phosphors were reported to be promising luminescent materials to solve above matter. In this study, controllable design of Ca₁₄Al₁₀Zn₆O₃₅:0.15Mn⁴⁺ (CAZO:0.15Mn⁴⁺) far red emitting phosphors was realized via pH assisted hydrothermal approach. The pure CAZO:0.15Mn⁴⁺ phosphors were obtained merely when the reaction pH was 1 or 2. Meanwhile, by adjusting the pH value of the reaction solution, far red emission CAZO:0.15Mn⁴⁺ phosphors with grains, sphere-like as well as aggregated bulk particles can be achieved at pH =?4, pH =?6 and pH =?10, respectively. Furthermore, the structures and morphologies depended photoluminescence (PL) performances of CAZO:0.15Mn⁴⁺ were checked. The best PL performance was found for the phosphor produced at pH =?6, while over acidic or alkaline conditions would lower the emission intensity. In addition, this phosphor also exhibit good thermal resistance which can maintain 78% initial intensity at 150?°C. The practical indoor tobacco cultivation demonstrated that CAZO:0.15Mn⁴⁺ obtained through this pH adjusted hydrothermal route is a promising phosphor for indoor plant growth lighting.     

Mn4+-activated KLaMgWO6: A new high-efficiency far-red phosphor for indoor plant growth LEDs

Novel Mn⁴⁺-activated KLaMgWO₆ red phosphors with different Mn⁴⁺ concentrations were successfully synthesized via a high-temperature solid-state reaction method. The phase formation, microstructure, photoluminescence properties, decay lifetimes and internal quantum efficiency were discussed to analyze the properties of the as-prepared phosphors. The samples belonged to monoclinic crystal system with enough WO₆ octahedrons that provided suitable sites for Mn⁴⁺ ions. Upon the excitation of 348?nm, KLaMgWO₆:Mn⁴⁺ phosphors gave bright far-red emission around 696?nm due to the ²E_g→⁴A_2g transition of Mn⁴⁺ ions. The critical concentration of Mn⁴⁺ was 0.6?mol% and the concentration quenching mechanism belonged to electric multipolar interaction. Besides, the CIE chromaticity coordinates of the KLaMgWO₆:0.6%Mn⁴⁺ phosphor were (0.7205, 0.2794) which located in deep red range, and its color purity reached up to 96.6%. The KLaMgWO₆:0.6%Mn⁴⁺ sample also exhibited high internal quantum efficiency of 43%. All of the admirable optical properties indicate that the KLaMgWO₆:Mn⁴⁺ phosphors can be applied to indoor plant growth illumination.     

Structural and luminescent properties of Eu3+-doped double perovskite BaLaMgNbO6 phosphor

Eu³⁺-activated BaLaMgNbO₆ red-emitting phosphors were synthesized by a high-temperature solid-state reaction method. Phase analysis and luminescence were characterized by X-ray diffraction (XRD) and photoluminescence excitation and emission spectra. The XRD patterns showed that BaLaMgNbO₆ had a monoclinic structure with space group P21/n. The excitation spectra consisted of a broad charge-transfer band and some sharp f-f absorption peaks characteristic of Eu³⁺. The intensity ratio of I₆₁₅/I₅₉₀ was used to detect the chemical environment of Eu³⁺. The chromaticity coordinates of BaLa_0.7Eu_0.3MgNbO₆ were (0.67, 0.33), indicating that the BaLaMgNbO₆:Eu³⁺ phosphors were excellent red-emitting phosphors. Under excitation by near-ultraviolet (UV) and blue light, the phosphor not only exhibited intense red emission but also showed high color quality. The Ozawa and Dexter energy-transfer theories were employed to calculate the theoretical quenching concentration and determine the concentration quenching mechanism. In addition, the activation energy of BaLa_0.7Eu_0.3MgNbO₆ was calculated through the Arrhenius equation. A configurational coordinate diagram was used to explain the thermal quenching mechanism.     

CaNb2O6:Bi3+体系荧光粉的制备及荧光性能研究

采用高温固相法合成了CaNb2O6∶Bi3+以及K+,Na+,Li+掺杂CaNb2O6∶Bi3+荧光粉,并用荧光光谱、XRD、场发射扫描电镜分析了材料的结构以及发光性能和机理。相对于纯CaNb2O6,Bi3+以及K+、Na+的引入极大的提升了荧光粉的发光强度,发光效果最好的材料为CaNb2O6∶1%Bi3+,15%K+。     

Crystal structure,luminescent properties and white light emitting diode application of Ba3GdNa(PO4)3F:Eu2+ single-phase white light-emitting phosphor

A series of single-phase white-light-emitting phosphors, Eu²⁺-activated Ba₃GdNa(PO₄)₃F phosphors were synthesized by solid-state reactions. The crystal structure of Ba₃GdNa(PO₄)₃F was been identified by Rietveld refinement of X-ray diffraction pattern. The Eu²⁺-activated Ba₃GdNa(PO₄)₃F phosphors exhibit broad excitation spectra from 250 to 420 nm, which matched well with the n-UV LED chips. Under the excitation of 365 nm, the emission spectrum almost covered the entire visible region including two emission bands peaked at 472 nm and 640 nm. Three different Eu²⁺ emission centers in Ba₃GdNa(PO₄)₃F:Eu²⁺ phosphor were confirmed by their fluorescence decay lifetimes. The optimal concentration of Eu²⁺ in Ba₃GdNa(PO₄)₃F:xEu²⁺ was 3 mol% and the corresponding concentration quenching mechanism was verified to be exchange coupling interaction. Furthermore, the white light-emitting diode fabricated with Ba₃GdNa(PO₄)₃F:0.05Eu²⁺ phosphor and a 370 nm UV chip has a CIE of (0.3267, 0.2976) with a color-rendering index of 78.4 at the CCT of 5287 K.     

Structure evolution and delayed quenching of the double perovskite NaLaMgWO6:Eu3+ phosphor for white LEDs

Eu³⁺ ions activated NaLaMgWO₆ phosphors were successfully synthesized by an improved sol-gel method using citric acid and polyethylene glycol as complexing agents. Crystal structure and doping site were investigated by XRD, Rietveld refinement and Raman spectra. The phosphors had monoclinic double perovskite structure with space group C2/m, as well as layered ordering of A-site and rock-salt ordering of B-site. The blueshift of Raman T_2g(1) mode manifested Eu³⁺ ions had entered into A-site. Thereafter, luminescence properties, such as excitation and emission spectra, CIE coordinates, concentration quenching and thermal quenching were discussed. The quenching concentration for hypersensitive electric dipole transition of Eu³⁺ reached up to 50.0 mol%. The delayed concentration quenching was observed in NaLaMgWO₆: Eu³⁺ phosphor. The theoretical quenching concentration was obtained based on L. Ozawa's theory, and the quenching mechanism on Dexter's theory. Excellent thermal stability of this phosphor shows that it is a potential red phosphor for solid state lighting.     

Photoluminescence properties of a double perovskite tungstate based red-emitting phosphor NaLaMgWO6:Sm3+

In this work, the conventional solid-state method was applied to synthesize a series of red-emitting NaLaMgWO₆:Sm³⁺ phosphors. The crystal structure, phase purity, morphology, particle size distribution as well as elemental composition of the as-prepared phosphors were investigated carefully with the aid of XRD, SEM, EDS, FT-IR analyses, indicating the high-purity and micron-sized NaLaMgWO₆:Sm³⁺ phosphors with monoclinic structure were prepared successfully. The spectroscopic properties of Sm³⁺ in NaLaMgWO₆ host including UV–vis diffuse reflection spectrum, photoluminescence excitation and emission spectra, decay curves, chromaticity coordinates and internal quantum efficiency were investigated in detail. Upon excitation with UV (290 nm) and n-UV (406 nm), NaLaMgWO₆:Sm³⁺ phosphor presented red emission corresponding to the ⁴G_5/2→⁶H_J (J = 5/2, 7/2, 9/2, and 11/2) transitions of Sm³⁺, in which the hypersensitive electronic dipole transition ⁴G_5/2→⁶H_9/2 (645 nm) was with the strongest emission intensity because Sm³⁺ ions were located at a lattice site with anti-inversion symmetry. The optimal concentration of Sm³⁺ was different for the given excitation wavelength such as 290 nm and 406 nm, which was interpreted by the extra effect of the energy transfer from W⁶⁺-O^2- group to Sm³⁺. The decay lifetime for ⁴G_5/2→⁶H_9/2 transition of Sm³⁺ was very short (< 1 ms) and decreased with the increasing Sm³⁺ concentration. The present investigation indicates that NaLaMgWO₆:Sm³⁺ phosphor could be a potential red component for application in w-LEDs.     

Design of a narrow-band blue-emitting Rb2Ba3(P2O7)2:Eu2+ phosphor with low thermal quenching for plant growth LEDs

Phosphor-converted light-emitting diodes (pc-LEDs) are commonly used to regulate the light environment to control the growth rates and improve the production efficiency of plant. Among them, the exploration of blue-emitting phosphors with high efficiency, low thermal quenching and excellent spectrum resemblance matching with the plant response spectrum is still challenging. Herein, a narrow-band blue-emitting Rb₂Ba₃(P₂O₇)₂:Eu²⁺ phosphor with high color purity of 93.4% has been developed. Under 345 nm excitation, it exhibits a blue emission band centered at 413 nm with a full width at half-maximum (FWHM) of 36 nm, and the emission spectrum of Rb₂Ba₃(P₂O₇)₂:0.060Eu²⁺ sample shows 85.7% spectrum resemblance with the absorption spectrum of chlorophyll-a in the blue region from 400 to 500 nm. In addition, the temperature-dependent emission spectra demonstrate that the Rb₂Ba₃(P₂O₇)₂:0.060Eu²⁺ phosphor has good thermal stability and small chromaticity shift, with the emission intensity dropping to 72.5% at 423 K of the initial intensity at 298 K and a chromaticity shift of 38 × 10^-3 at 498 K. All results suggest that the blue-emitting Rb₂Ba₃(P₂O₇)₂:Eu²⁺ phosphor has potential application in plant growth LEDs.     

Synthesis and photoluminescence properties of MgAl(PO4)O:Eu red phosphor for white LEDs

Eu³⁺-activated MgAl(PO₄)O:phosphor has been synthesized by a high temperature solid state reaction and efficient red emission under near-ultraviolet excitation is observed. The emission spectrum shows a dominant peak at 594 nm due to the ⁵D₀→⁷F₁ transition of Eu³⁺. The excitation spectrum is coupled well with the emission of UV LED (350–410 nm). The effect of Eu³⁺ concentration on the luminescent properties of MgAl(PO₄)O:Eu³⁺ and the mechanism of concentration quenching of Eu³⁺ are studied. The results show that MgAl(PO₄)O:Eu³⁺ is a promising red-emitting phosphor for white LEDs.     

Preparation of Ca4Mg5(PO4)6:Eu,Mn phosphor and its photoluminescence properties

Eu²⁺ and Mn²⁺ singly doped and Eu²⁺/Mn²⁺-codoped Ca₄Mg₅(PO₄)₆ phosphors were synthesized via combustion synthesis. Mn²⁺-singly doped Ca₄Mg₅(PO₄)₆ phosphor exhibits a single red emission in the wavelength range of 500–700 nm due to the ⁴T₁(⁴G)→⁶A₁(⁶S) transition of Mn²⁺. Eu²⁺/Mn²⁺ co-doped phosphor emits two distinctive luminescence bands: a blue one centered at 442 nm originating from Eu²⁺ and a broad red-emitting one peaked at 609 nm from Mn²⁺. Energy transfers from Eu²⁺ to Mn²⁺ were discovered by directly observing significant overlap of the excitation spectrum of Mn²⁺ and the emission spectrum of Eu²⁺ as well as the systematic relative decline and growth of emission bands of Eu²⁺ and Mn²⁺, respectively. Based on the principle of energy transfer, the relative intensities of blue and red emission could be tuned by adjusting the contents of Eu²⁺ and Mn²⁺.     

Blue-red dual color emitting phosphor Cs2NaLuCl6: Sb3+, Ho3+ for plant growth LEDs

The phosphor-converted light emitting diode (pc-LED) is an efficient light source to adjust growth rhythm and raise yield of plant. Blue and red light play the dominant role in the process of plant growth, thus it is meaningful to search the blue-red dual emission phosphors with high quantum field and better thermal stability for developing plant growth LED. Herein, the blue-red dual emission phosphors were synthesized by co-doping Sb³⁺ and Ho³⁺ into the Cs₂NaLuCl₆, which emitted blue (454 nm) to red (657 nm) light with increasing the content of Ho³⁺ to 25% and their relative intensity could be tuned through adjusting the concentration of Ho³⁺ due to the efficient energy transfer from Sb³⁺ to Ho³⁺. The intensity of blue emission from Sb³⁺ and red emission from Ho³⁺ could maintain 78.4 and 75.8% of the room temperature at 150 °C, respectively. Furthermore, the spectra of fabricated blue and red LEDs match well with the absorption of carotenoid, Phytochrome and Chlorophyll b, implying the samples possess great application potential in plant growth LED.     

LiCa3MgV3O12:Sm3+: A new high-efficiency white-emitting phosphor

A novel single-phased white-light-emitting phosphor Sm³⁺ doped LiCa₃MgV₃O₁₂ (LCMV) was developed. The LCMV host was one self-activated bluish-green emitting phosphor, which possessed an efficient excitation band in the 250–400?nm wavelength range and showed an intense broadband bluish-green emission with internal quantum efficiency (IQE) of 39%. Doping Sm³⁺ ions in to LCMV host induced tunable-color emissions, due to the energy transfer from [VO₄]^3? to Sm³⁺ ions. Importantly, under 340?nm excitation, the LCMV:Sm³⁺ can emitted bright white light by combining the self-activated luminescence of LCMV host and the red emissions of Sm³⁺ ions, and the IQE of the white-emitting composition-optimized LCMV:0.01Sm³⁺ phosphors reached up to 45%. These white-emitting LCMV:Sm³⁺ phosphors have potential applications in white light-emitting diodes and optical display devices.     

Synthesis and photoluminescence enhancement of Ca3Sr3(VO4)4:Eu3+ red phosphors by co-doping with La3+

In this study, a series of red-emitting Ca₃Sr₃(VO₄)₄:Eu³⁺ phosphors co-doped with La³⁺ was prepared using the combustion method. The microstructures, morphologies, and photoluminescence properties of the phosphors were investigated. All Ca₃Sr₃(VO₄)₄:Eu³⁺, La³⁺ samples synthesized at temperatures greater than 700 ℃ exhibited the same standard rhombohedral structure of Ca₃Sr₃(VO₄)₄. Furthermore, the Ca₃Sr₃(VO₄)₄:Eu³⁺, La³⁺ phosphor was effectively excited by near-ultraviolet light of 393 nm and blue light of 464 nm. The strong excitation peak at 464 nm corresponded to the ⁷F₀→⁵D₂ electron transition of Eu³⁺. The strong emission peak observed at 619 nm corresponded to the ⁵D₀→⁷F₂ electron transition of Eu³⁺. Co-doping with La³⁺ significantly improved the emission intensity of Ca₃Sr₃(VO₄)₄:Eu³⁺ red phosphors. The optimum luminescence of the phosphor was observed at Eu³⁺ and La³⁺ concentrations of 5% and 6%, respectively. Moreover, co-doping with La³⁺ also improved the fluorescence lifetime and thermal stability of the Ca₃Sr₃(VO₄)₄:Eu³⁺ phosphor. The CIE chromaticity coordinate of Ca₃Sr₃(VO₄)₄:0.05Eu³⁺, 0.06La³⁺ was closer to the NTSC standard for red phosphors than those of other commercial phosphors; moreover, it had greater color purity than that of all the samples tested. The red emission intensity of Ca₃Sr₃(VO₄)₄:0.05Eu³⁺, 0.06La³⁺ at 619 nm was ~1.53 times that of Ca₃Sr₃(VO₄)₄:0.05Eu³⁺ and 2.63 times that of SrS:Eu²⁺. The introduction of charge compensators could further increase the emission intensity of Ca₃Sr₃(VO₄)₄:Eu³⁺, La³⁺ red phosphors. The phosphors synthesized herein are promising red-emitting phosphors for applications in white light-emitting diodes under irradiation by blue chips.     

Photoluminescence enhancement of novel K(Y,Lu)CaWO6: Eu3+ red phosphor prepared by controllable citrate-EDTA complexing method

Novel double-perovskite K(Y_0.95-xLu_xEu_0.05)CaWO₆ red phosphors were successfully prepared by the controllable citrate-EDTA complexing method. XRD with structure refinement, FTIR, Raman and photoluminescence spectra were combined to systematically investigate the structure parameters and luminescence properties of prepared phosphors. The substitution of Lu³⁺ with smaller ionic radius resulted in the lower symmetry even with the same space group of C2/m, which was also directly observed from the red shift and splitting of Raman T_2?g(1) mode. The concentration higher than x?=?0.6 made the intensity alteration in the excitation spectra from charge transfer band to 4f?4f of Eu³⁺. The obvious enhancements of red emission at 615?nm were obtained under both blue and ultraviolet lights, respectively, and reached almost the same intensity at x?=?0.6. Meanwhile, the more standard red light could be found by the gradual shifts of CIE chromaticity coordinates and bigger ratio of red/orange emission. The substitution of Lu³⁺ improved the quality and emission intensity of red light of this double perovskite system and the composition optimized phosphor of K(Y_0.35Lu_0.6Eu_0.05)CaWO₆ exhibited great potential in the application of white LEDs.     

Synthesis and photoluminescence properties of a novel red phosphor SrLaGaO4:Mn4+

A novel Mn⁴⁺-doped strontium lanthanum gallate red phosphor SrLaGaO₄:Mn⁴⁺ has been successfully prepared via the conventional solid-state reaction method. Phase purity, photoluminescence excitation/emission spectra, concentration quenching, decay curves, and temperature-dependent photoluminescence have been investigated systematically. SrLaGaO₄:Mn⁴⁺ phosphor exhibits broad excitation band from 250 to 600 nm and emits intense red light centered at 716 nm arising from spin-forbidden transition, ²E → ⁴A₂ of Mn⁴⁺. The optimal dopant concentration of Mn⁴⁺ is determined to be 0.2 mol%. Dipole-dipole interaction is supposed to be the mechanism of concentration quenching. The crystal-field strength Dq, the Racah parameters B and C, and the nephelauxetic ratio β₁ of SrLaGaO₄:Mn⁴⁺ have been calculated according to its luminescent spectra. Our systematic investigation on this new phosphor can provide a reference for the development of red-emitting phosphor.     

Enhanced luminescence properties and device applications of Tb3+-doped Cs4PbBr6 perovskite quantum dot glass

Cs₄PbBr₆ perovskite quantum dots (QDs) have unique optoelectronic properties and are expected to become a new generation of luminescent materials. However, poor stability, low photoluminescence quantum yield (PLQY), and poor understanding as to the origin of photoluminescence behavior limit its further application. In this study, a series of Tb³⁺-doped Cs₄PbBr₆ perovskite QD glasses with excellent stability were obtained through the optimization of Tb³⁺ doping concentration and in-situ crystallization temperature. Density functional theory calculations and experimental characterization showed that an appropriate amount of lattice-incorporated Tb³⁺ ions can reduce structural defects in QDs, improve the PLQY, and reduce the QD heavy-metal requirements. Notably, the maximum PLQY value reached 47%, which is near to the Cs₄PbBr₆ perovskite crystal. Furthermore, a high-performance white light-emitting diode (WLED) device was prepared. The device featured a color rendering index of 80 and luminous efficiency of 41 lm W^?1. Finally, a QD glass with double emission peaks was prepared by controlling the in-situ crystallization temperature (550 °C). The temperature sensitivity of the QD glass was then studied using the fluorescence intensity ratio method. The maximum relative temperature sensitivity (Sr) reached 2.03% K^?1, which is higher than the previously reported value. Thus, the method proposed in this study can greatly improve the photoluminescence properties of Cs₄PbBr₆ QD glass and expand its applications in WLED and visual temperature sensing.     

Alkali metal ion substitution induced luminescence enhancement of NaLaMgWO6:Eu3+ red phosphor for white light-emitting diodes

Alkali metal ion substitution is an effective strategy to improve the luminescence properties of phosphors. In this work, a series of red-emitting phosphors Na_1-xLi_x/2K_x/2La_0.6Eu_0.4MgWO₆ were prepared by a traditional high-temperature solid-state reaction. Their phase structure, microstructure, luminescence properties and potential application in phosphor-converted white light-emitting diodes (pc-WLEDs) were investigated in detail. X-ray diffraction (XRD) result revealed the formation of a solid solution when x?≤?0.3, which kept monoclinic structure of NaLaMgWO₆. Photoluminescence investigation indicated that the partial substitution of Li⁺/K⁺ ions for Na⁺ ions improved largely the red emission of Eu³⁺. Based on the optimized Na_0.7Li_0.15K_0.15La_0.6Eu_0.4MgWO₆ sample with relatively good thermal stability, a WLED device was fabricated by combining a near-ultraviolet (NUV) chip (~400?nm) with the phosphor mixture of commercial green/blue phosphors and the optimized red phosphor. The results indicated that the optimized red phosphor in this work could be a potential candidate for WLEDs pumped by NUV chips.     

Synthesis,structure and luminescent properties of Eu3+ doped Ca3LiMgV3O12 color-tunable phosphor

A new vanadate Ca₃LiMgV₃O₁₂ and its Eu³⁺-doped counterparts were synthesized. Rietveld confinement result of Ca₃LiMgV₃O₁₂ host indicates that it belongs to cubic space group Ia-3d with parameters of a =?12.4300?Å, V =?1920.49?ų, Z?=?8. Under UV excitation, pure Ca₃LiMgV₃O₁₂ exhibits a bluish-green broadband emission at 490?nm, while Eu³⁺ doped Ca₃LiMgV₃O₁₂ shows one bluish-green broad band with a series of red sharp peaks, which originate from the V⁵⁺-O^2- charge transfer and the Eu³⁺ intra-4f transitions, respectively. The occurrence of VO₄→Eu³⁺ energy transfer is confirmed by decay lifetime analysis and time-resolved emission spectra. It is found that emitting color varies from bluish-green to orange-red with increasing Eu³⁺ concentration. VO₄ bluish-green and Eu³⁺ red emission shows different thermal quenching response with increasing temperature, due to their different activation energy.     

Synthesis of MFe2O4 (M=Mg2+, Zn2+, Mn2+) spinel ferrites and their structural,elastic and electron magnetic resonance properties

Structural, elastic and electron magnetic resonance investigations of spinel ferrites with the formula MFe₂O₄ (M = Mg²⁺, Zn²⁺, Mn²⁺) synthesized by the sol-gel auto-combustion method are reported here. XRD patterns revealed the co-existence of secondary phases along with the ferrite phase. The lattice parameter (8.301?Å, 8.366?Å and 8.434?Å) was found to be varying according to the ionic radii of cations. As determined by scanning electron microscopy (SEM), ZnFe₂O₄ has a comparatively narrow distribution of grain sizes (1.3–3.8?µm) compared to those in MnFe₂O₄ (0.8–4.3?µm) and MgFe₂O₄ (0.3–4.8?µm). The estimated values of average crystallite sizes (17.5?nm, 21.3?nm and 23.3?nm) determined from the X-ray diffraction peaks are considerably less than the average grain sizes (1.3?µm, 1.6?µm and 2.7?µm) estimated from the SEM histograms. The vibrational frequencies in FTIR spectra are in the conformity with the cubic spinel structure and their variation supports the variation of lattice parameter. Equal values of Poission's ratio (0.35) were obtained for the three systems which represent the isotropic behaviour of spinel ferrite systems. The exceptional low value of Lande's g-parameter for ZnFe₂O₄ indicates the dominance of Fe³⁺–O–Fe³⁺ superexchange interaction. Though cation redistribution is possible in the present ferrite systems, the secondary phases existed in these ferrite systems are predominantly influencing the structural, elastic and electron magnetic resonance properties.     

Color-tunable properties based on complex anion substitution in Eu2+ doped Ca8Sc2(PO4)6-y(SiO4)1+y phosphor

We synthesized and investigated the effect of Eu²⁺ ions doping in a novel phosphor-silicate Ca₈Sc₂(PO₄)₆(SiO₄) phosphor. The structure and photoluminescence properties were determined by X-ray powder diffraction Rietveld refinement, diffuse reflection spectra, emission-excitation spectra, decay curves and temperature dependence spectra. The phosphors showed an asymmetric broad-band blue emission (Eu²⁺) with peak at 470?nm. Furthermore, we presented the Ca_7.96Sc₂(PO₄)_6-y(SiO₄)_1+y:0.04Eu²⁺ phosphors by co-substituting [Eu²⁺-Si⁴⁺] for [Ca²⁺-P⁵⁺], and different behaviors of luminescence evolution in response to structural variation were verified among the series of phosphors. The results were attributed to the presence of multi Ca²⁺ sites, resulting in the mixing of blue and green emissions for Eu²⁺ ions. The complex anion substitution of [PO₄]^3- by [SiO₄]^4- induced an increased crystal field splitting of the Eu²⁺ ions, which caused a decrease in emission energy from the 5d excited state to the 4f ground state and a resultant red-shift from 470?nm to 520?nm. All the properties indicated that the Ca₈Sc₂(PO₄)₆(SiO₄):Eu²⁺ phosphors have potential application for color-tunable WLEDs.