Novel Broadband Excited and Linear Red‐Emitting Ba2Y(BO3)2Cl: Ce3+, Tb3+, Eu3+ Phosphor: Luminescence and Energy Transfer

A series of Ce³⁺, Tb³⁺, Eu³⁺ tri‐doped Ba₂Y(BO₃)₂Cl red‐emitting phosphor have been synthesized by solid‐state method. The Ce³⁺→Tb³⁺→Eu³⁺ energy‐transfer scheme has been proposed to realize the sensitization of Eu³⁺ ion emission by Ce³⁺ ions. Following this energy‐transfer model, near‐UV convertible Eu³⁺‐activated red phosphors have been obtained in Ba₂Y(BO₃)₂Cl: Ce³⁺, Tb³⁺, Eu³⁺ phosphors. Energy transfers from Ce³⁺ to Tb³⁺, and Tb³⁺ to Eu³⁺, as well as corresponding energy‐transfer efficiencies are investigated. The combination of narrow‐line red emission and near‐UV broadband excitation makes Ba₂Y(BO₃)₂Cl: Ce³⁺, Tb³⁺, Eu³⁺ as a novel and efficient red phosphor for NUV LED applications.     

Luminescence properties and energy transfer of GdAl3(BO3)4:Ce3+, Tb3+ phosphor

Ce³⁺ and Tb³⁺ singly doped and co-doped GdAl₃(BO₃)₄ phosphors were synthesized by solid state reaction. The crystal structure, the luminescent properties, the lifetimes and the temperature-dependent luminescence characteristic of the phosphors were investigated. Through an effective energy transfer, the emission spectra of GdAl₃(BO₃)₄:Ce³⁺, Tb³⁺ phosphor contains both a broad band in the range of 330–400 nm originated from Ce³⁺ ions and a series of sharp peaks at 484, 541, 583, and 623 nm due to Tb³⁺ ions. The energy transfer from Ce³⁺ to Tb³⁺ in GdAl₃(BO₃)₄ host is demonstrated to be phonon assisted nonradiative energy transfer via a dipole–dipole interaction.     

Tunable single-phase white-light-emitting Ba2Mg(BO3)2:Ce3+, Na+, Tb3+, Eu2+ phosphor based on energy transfer

A series of white-light-emitting phosphors of single-phase Ba₂Mg(BO₃)₂:Ce³⁺, Na⁺, Tb³⁺, Eu²⁺ were synthesized by conventional solid-state reaction. The crystal structure of the host was characterized by X-ray diffraction and investigated by Rietveld refinement. Photoluminescence properties were studied in detail. The energy transfer from Ce³⁺ to Tb³⁺ in Ba₂Mg(BO₃)₂ host was investigated and demonstrated to be a resonant type via a quadrupole–quadrupole mechanism. White light with wavelength tunable was realized by coupling the emission bands peaking at 417, 543 and 626 nm attributed to Ce³⁺, Tb³⁺ and Eu²⁺, respectively. By properly tuning the relative composition of Ce³⁺(Na⁺)/Tb³⁺/Eu²⁺, optimized Commission Internationale de l׳Eclairage (CIE) chromaticity coordinates (0.363, 0.295), high color rendering index (CRI) 90 and low correlated color temperature (CCT) 3793 K were obtained from the phosphor of Ba_1.90Ce_0.04Na_0.04Eu_0.02Mg_0.94Tb_0.06(BO₃)₂ upon the excitation of 296 nm UV radiation. These results indicate that Ba₂Mg(BO₃)₂:Ce³⁺, Na⁺, Tb³⁺, Eu²⁺ phosphor has a potential application as an UV radiation down-converting phosphor in white-light-emitting diodes.     

Photoluminescence Properties of Color‐Tunable Ca3La6(SiO4)6: Ce3+, Tb3+ Phosphors

A series of newly developed color‐tunable Ca₃La₆(SiO₄)₆: Ce³⁺, Tb³⁺ phosphors were successfully prepared in this study. The crystal structures of the prepared phosphors were revealed to be hexagonal with space group P6₃/m, and the lattice parameters were evaluated via utilizing the Rietveld refinement method. Upon excitation at 288 nm, the emission spectra of Ce³⁺and Tb³⁺ ions co‐doped Ca₃La₆(SiO₄)₆ phosphors included a blue emission band and several emission lines. The blue emission band with a peak at 420 nm originated in the f–d transitions of Ce³⁺ ions, and the emission lines in the range of 450–650 nm were assigned to the ⁵D₄ → ⁷F_J (J = 6, 5, 4, 3) transitions of Tb³⁺ ions. Increasing the doping content of Tb³⁺ ions considerably strengthened Tb³⁺ emission and reduced Ce³⁺ emission owing to the energy transfer from Ce³⁺ to Tb³⁺ ions. The mechanism of the energy transfer was confirmed to be a dipole–dipole interaction. The effective energy transfer from Ce³⁺ to Tb³⁺ ions caused a color shift from purplish‐blue to yellowish‐green. Color‐tunable Ca₃La₆(SiO₄)₆: Ce³⁺, Tb³⁺ phosphors have the potential to be utilized in light‐emitting diodes with proper modulation of the amount of Tb³⁺ ions.     

Multicolour tunable luminescence of thermal-stable Ce3+/Tb3+/Eu3+-triactivated Ca3Gd(GaO)3(BO3)4 phosphors via Ce3+ → Tb3+ → Eu3+ energy transfer for near-UV WLEDs applications

A series of single-component blue, green and red phosphors have been fabricated based on the Ca₃Gd(GaO)₃(BO₃)₄ host through doping of the Ce³⁺/Tb³⁺/Eu³⁺ ions, and their crystal structure and photoluminescence properties have been discussed in detail. A terbium bridge model via Ce³⁺ → Tb³⁺ → Eu³⁺ energy transfer has been studied. The emission colours of the phosphors can be tuned from blue (0.1661, 0.0686) to green (0.3263, 0.4791) and eventually to red (0.5284, 0.4040) under a single 344 nm UV excitation as the result of the Ce³⁺ → Tb³⁺ → Eu³⁺ energy transfer. The energy transfer mechanisms of Ce³⁺ → Tb³⁺ and Tb³⁺ → Eu³⁺ were found to be dipole-dipole interactions. Importantly, Ca₃Gd(GaO)₃(BO₃)_4:Ce³⁺,Tb³⁺,Eu³⁺ phosphors had high internal quantum efficiency. Moreover, the study on the temperature-dependent emission spectra revealed that the Ca₃Gd(GaO)₃(BO₃)_4:Ce³⁺,Tb³⁺,Eu³⁺ phosphors possessed good thermal stability. The above results indicate that the phosphors can be applied into white light-emitting diodes as single-component multi-colour phosphors.     

Synthesis and photoluminescent properties of high-efficient color-tunable Ba3Y2B6O15: Ce3+, Tb3+ phosphors

High-efficient Ce³⁺/Tb³⁺ co-doped Ba₃Y₂B₆O₁₅ phosphors with multi color-emitting were firstly prepared, and their structural and luminescent properties were studied by XRD Rietveld refinement, emission/excitation spectra, fluorescence lifetimes as well as temperature-variable emission spectra. Upon 365?nm excitation, the characteristic blue Ce³⁺ band along with green Tb³⁺ peaks were simultaneously found in the emission spectra. Moreover, by increasing concentration of Tb³⁺, a blue-to-green tunable emitting color could be realized by effective Ce³⁺→Tb³⁺ energy transfer. Furthermore, all Ba₃Y₂B₆O₁₅: Ce³⁺, Tb³⁺ phosphors exhibit high internal quantum efficiency of ~?90%, while the temperature-variable emission spectra reveal that the phosphors possess impressive color stability as well as good thermal stability (T₅₀ =?~?120?°C). The results indicate that these efficient color-tuning Ba₃Y₂B₆O₁₅: Ce³⁺, Tb³⁺ might be candidate as converted phosphor for UV-excited light-emitting diodes.     

Color tunable Ba3Lu(PO4)3:Tb3+,Mn2+ phosphor via Tb3+→Mn2+ energy transfer for white LEDs

Series of UV excited Ba₃Lu(PO₄)₃:Tb³⁺,Mn²⁺ phosphors with tunable green to red emissions had been prepared using solid state reactions. Powder X-ray diffraction and Rietveld structure refinement were used to investigate the phase purity and crystal structure of the prepared samples. Under UV excitation, the Ba₃Lu(PO₄)₃:Tb³⁺,Mn²⁺ samples exhibited not only the typical Tb³⁺ emission peaks but also the broad emission band of Mn²⁺ ions due to the efficient Tb³⁺→Mn²⁺ energy transfer which had been verified by luminescence spectra and decay curves. Utilizing the Inokuti-Hirayama model, the Tb³⁺→Mn²⁺ energy transfer mechanism was determined to be the electronic dipole–quadrupole interaction. Moreover, the emission spectra of Ba₃Lu(PO₄)₃:0.80Tb³⁺,0.015Mn²⁺ sample at different temperatures manifested that our prepared phosphors possessed good thermal stability. The luminescence properties investigation results revealed the potential value of Ba₃Lu(PO₄)₃F:Tb³⁺,Mn²⁺ in application for UV excited phosphor converted white light emitting diodes.     

The Energy Transfer and Thermal Stability of a Blue‐Green Color Tunable K2CaP2O7:Ce3+,Tb3+ Phosphor

Novel blue‐green emitting Ce³⁺‐ and Tb³⁺‐activated K₂CaP₂O₇ (KCPO) luminescent materials were synthesized via a solid‐state reaction method. X‐ray diffraction, luminescence spectroscopy, decay time, and fluorescent thermal stability tests have been used to characterize the prepared samples. The KCPO:Ce³⁺,Tb³⁺ luminescence spectra show broad band of Ce³⁺ ions and characteristic line of Tb³⁺ ion transition (⁵D₄–⁷F₅). The color variation in the light emitting from blue to green under UV excitation can be obtained by tailoring the Tb³⁺ content in KCPO:Ce³⁺. Besides, Ce³⁺ ions obviously intensify Tb³⁺ ion emission through an effective energy transfer process, which was confirmed from decay curves. The energy transfer efficiency was determined to be 82.51%. A resonant type mechanism via the dipole–quadrupole interaction can be proposed for energy transfer. As a whole, the KCPO:Ce³⁺,Tb³⁺ phosphor exhibits excellent performance in the range from 77 to 673 K, indicating the phosphors are highly potential candidates for solid‐state lighting.     

White‐emitting phosphor Ba2B2O5:Ce3+, Tb3+, Sm3+: Luminescence,energy transfer,and thermal stability

A series of Ba₂B₂O₅: RE (RE=Ce³⁺/Tb³⁺/Sm³⁺) phosphors were synthesized using high‐temperature solid‐state reaction. The X‐ray diffraction (XRD), luminescent properties, and decay lifetimes are utilized to characterize the properties of the phosphors. The obtained phosphors can emit blue, green, and orange‐red light when single‐doped Ce³⁺, Tb³⁺, and Sm³⁺. The energy can transfer from Ce³⁺ to Tb³⁺ and Tb³⁺ to Sm³⁺ in Ba₂B₂O₅, but not from Ce³⁺ to Sm³⁺ in Ce³⁺ and Sm³⁺ codoped in Ba₂B₂O₅. However, the energy can transfer from Ce³⁺ to Sm³⁺ through the bridge role of Tb³⁺. We obtain white emission based on energy transfer of Ce³⁺→Tb³⁺→Sm³⁺ ions. These results reveal that Ce³⁺/Tb³⁺/Sm³⁺ can interact with each other in Ba₂B₂O₅, and Ba₂B₂O₅ may be a potential candidate host for white‐light‐emitting phosphors.     

Synthesis and Photoluminescence Characteristics of YAl3(BO3)4:Tb3+ Phosphors by Combustion Process

Terbium‐activated YAl₃(BO₃)₄ (YAl₃(BO₃)₄:Tb³⁺) phosphors were synthesized by both combustion method and solid‐state reaction. It was found that the pure‐phase YAl₃(BO₃)₄ phosphors synthesized by combustion method were obtained at 1000°C, which was 200°C lower than that by solid‐state reaction. The average particle size of the combustion‐derived phosphors increased with increasing temperatures. The luminescence characteristics in ultraviolet (UV) — vacuum ultraviolet (VUV) ranges for the YAl₃(BO₃)₄:Tb³⁺ phosphors were investigated. The bands from 175 nm to 300 nm were attributed to the 4f⁸‐4f⁷5d¹ transitions of Tb³⁺. The other strong bands in the region from 125 nm to 175 nm were assigned to host absorption. The emission spectra showed the strongest emission at 542 nm corresponding to the ⁵D₄→⁷F₅ transition of Tb³⁺. Moreover, the combustion‐derived YAl₃(BO₃)₄:Tb³⁺ phosphors generated more intense luminescence than the solid‐state‐derived phosphors under UV excitation.     

NaBaY(BO3)2:Ce3+,Tb3+: A novel sharp green‐emitting phosphor used for WLED and FEDs

A new borate phosphor NaBaY(BO₃)₂: Ce³⁺, Tb³⁺ (NBY:Ce³⁺, Tb³⁺) was successfully synthesized under low temperature designed to put into application in the fields of ultraviolet (UV)‐excited light emitting diodes (LEDs) and field emission displays (FEDs). The structure distortion between Ce³⁺, Tb³⁺ single‐ and co‐doping NBY was discussed by X‐ray powder diffraction Rietveld refinement, high‐resolution transmission electron microscopy (HRTEM) and spectra. NBY: Ce³⁺, Tb³⁺ presents a wide absorption band ranging from 310 to 400 nm and efficient green emission (λ_max = 542 nm) with a full‐width at half‐maximum of 3.3 nm. The remarkable thermal stability has also been tested, indicating that the intensity at 200°C is still beyond 70% of the original intensity. In addition, a white LED device was manufactured by connecting a 370 nm UV chip with a blend of BaMaAl₁₀O₁₇: Eu²⁺ (BAM: Eu²⁺), NBY: Ce³⁺, Tb³⁺ and CaAlSiN₃: Eu²⁺. The color coordinate, correlated color temperature and color rendering index of the manufactured LED device were (0.335, 0.347), 5511 K and 80.16, respectively. Meanwhile, the cathodoluminescence (CL) spectra under the various conditions of probe currents and accelerating voltages were also analyzed. Through successive excitation of low‐voltage electron‐beam, the wonderful performances of degradation property and color stability were obtained. These results suggest that the green‐emitting NBY: Ce³⁺, Tb³⁺ phosphor has the prospect of becoming applications in white UV LEDs and FEDs.     

Optical Performances of YAG:Re3+ (Re = Ce,Eu) Phosphor Films with Co‐Doping Tb3+ as Energy‐Transfer Sensitizer

The paper investigates the effect of co‐doping Tb³⁺ as an energy‐transfer sensitizer on optical properties of YAG:Re³⁺ (where, Re = Ce, Eu) phosphor films synthesized by sol–gel route. The results suggest that, Tb³⁺ is a promising sensitizer for improving the optical performances of the as‐prepared YAG:Re³⁺ films, and a Tb³⁺ co‐doping concentration of 20% was found to be an optimum level on account of Tb³⁺ concentration quenching. Due to the energy‐transfer processes of Tb³⁺→Re³⁺, the as‐prepared Y_0.8 Tb_0.2AG:Re³⁺ films displayed strong abilities of absorption in the ultraviolet (UV) light range, and bright green–yellow emission for YAG:Ce³⁺ or red emission for YAG:Eu³⁺ under 275 nm irradiation, which could be utilized for UV‐excited WLED and display applications.     

Structure and Photoluminescence of A Blue‐Green‐Emitting Phosphor for Near‐UV White LEDs

A series of phosphors Ca_12(0.97?x)Al₁₄O₃₂F₂: 0.03Ce³⁺, xTb³⁺ have been prepared by a hightemperature solid‐state reaction using boric acid as flux. These oxyfluorides crystallize in cubic structure, space group. Under the near ultraviolet excitation within wavelength range 310–390 nm, Ca_12(0.97?x)Al₁₄O₃₂F₂: 0.03Ce³⁺, xTb³⁺ phosphors exhibit an intense emission covering a broad band of 370–500 nm derived from the 5d→4f transitions of Ce³⁺ and a characteristic emission at 544 nm of Tb³⁺. The emission can be tuned from blue to green by altering the relative ratio of Ce³⁺ to Tb³⁺ in the composition. The energy‐transfer mechanism from Ce³⁺ to Tb³⁺ is investigated based on the site occupancy of the luminescence center in the crystal structure of the Ca₁₂Al₁₄O₃₂F₂ host. More importantly, when a certain amount of boric acid is added as flux in the synthesis, the fluorescence intensity of the phosphors increases about 65%. Because of its broad excitation and efficiently tunable blue to green luminescence, the Ca_12(0.97?x)Al₁₄O₃₂F₂: 0.03Ce³⁺, xTb³⁺ phosphors may find promising application as a near UV‐convertible phosphor for white‐light‐emitting diodes.     

Luminescence properties and energy transfer investigations of Sr2B2O5:Ce3+,Tb3+ phosphors

Ce³⁺ and Tb³⁺ co-doped Sr₂B₂O₅ phosphors were synthesized by the solid-state method. X-ray diffraction (XRD) was used to characterize the phase structure. The luminescent properties of Ce³⁺ and Tb³⁺ co-doped Sr₂B₂O₅ phosphors were investigated by using the photoluminescence emission, excitation spectra and reflectance spectra, respectively. The excitation spectra indicate that this phosphor can be effectively excited by near ultraviolet (n-UV) light of 317 nm. Under the excitation of 317 nm, Sr₂B₂O₅:Ce³⁺,Tb³⁺ phosphors exhibited blue emission corresponding to the f–d transition of Ce³⁺ ions and green emission bands corresponding to the f–f transition of Tb³⁺ ions, respectively. The Reflectance spectra of the Sr₂B₂O₅:Ce³⁺,Tb³⁺ phosphors are noted that combine with Ce³⁺ and Tb³⁺ ion absorptions. Effective energy transfer occurred from Ce³⁺ to Tb³⁺ in Sr₂B₂O₅ host due to the observed spectra overlap between the emission spectrum of Ce³⁺ ion and the excitation spectrum of Tb³⁺ ion. The energy transfer efficiency from Ce³⁺ ion to Tb³⁺ ion was also calculated to be 90%. The phosphor Sr₂B₂O₅:Ce³⁺,Tb³⁺ could be considered as one of double emission phosphor for n-UV excited white light emitting diodes.     

A New Blue‐Emitting Phosphor of Ce3+‐Activated Fluorosilicate Apatite Ba2Y3[SiO4]3F

Blue‐emitting phosphor of Ce³⁺‐activated fluorosilicate apatite Ba₂Y₃[SiO₄]₃F was prepared via conventional solid‐state reaction method. The X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) excitation and emission spectra, and the decay curves (lifetimes) were applied to characterize the phosphors. The effects of Ce³⁺ activator concentration on the luminescence properties were investigated. Ba₂Y_2.85Ce_0.15[SiO₄]₃F exhibits the brightest blue emission with CIE coordinates of (x = 0.231, y = 0.301). The crystallographic site of Ce³⁺ ions in Ba₂Y₃[SiO₄]₃F lattices was identified. Two kinds of crystallographic Ce³⁺ occupying MI and MII sites in Ba₂Y₃[SiO₄]₃F lattices result in two distinct emission centers. The internal PL quantum efficiency, the temperature‐dependent luminescence, and the activation energy of thermal quenching were investigated to evaluate the potential application. This is a new kind of blue‐emitting phosphor based on apatite structure.     

Bright White‐Emitting Phosphors Ba2Gd(BO3)2Cl: Dy3+/Dy3+‐Tm3+ for Hg‐Free Lamps and White LEDs Applications

Spectroscopic properties of Ba₂Gd(BO₃)₂Cl: Dy³⁺ and Ba₂Gd(BO₃)₂Cl: Dy³⁺, Tm³⁺ under vacuum ultraviolet (VUV) and ultraviolet (UV) light excitations were investigated. Dy³⁺ single‐doped Ba₂Gd(BO₃)₂Cl showed broad absorption band in the VUV region, and bright warm white light with chromaticity coordinates (CIE) of (0.340, 0.381) upon VUV excitation at 172 nm, demonstrating this phosphor's applicability in mercury free lamps. Upon direct excitation Tm³⁺ from its ⁶F₆ level to ¹D₂ level, the decrease of emission intensity and lifetime of Tm^{3+ 1}D₂–³F₄ emission with increasing concentration of Dy³⁺ in Ba₂Gd(BO₃)₂Cl: Dy³⁺, Tm³⁺ confirmed the occurrence of energy transfer from Tm³⁺ to Dy³⁺. In addition, Ba₂Gd(BO₃)₂Cl: Dy³⁺, Tm³⁺ could be efficiently excited by 358 nm UV light and its emission color could be tuned from blue to yellow by codoping Tm³⁺. When 1% Tm³⁺ and 5% Dy³⁺ were codoped in the Ba₂Gd(BO₃)₂Cl, intensive white‐emitting light with CIE of (0.352, 0.328) and correlated color temperature of 4589 K was achieved upon 358 nm excitation, revealing the potential application of Ba₂Gd(BO₃)₂Cl: Dy³⁺, Tm³⁺ for white light‐emitting diodes (LEDs).     

Enhanced luminescence properties and energy transfer in Ce3+ and Tb3+ co-doped NaCaBO3 phosphor

A series of color-tunable NaCaBO₃: Ce³⁺, Tb³⁺ phosphors have been synthesized on the basis of efficient Ce³⁺→Tb³⁺ energy transfer. The photoluminescence emission and excitation spectra, the lifetime, and the effect of Tb³⁺ concentration are investigated in detail. The enhanced photoluminescence of Tb³⁺ with sharp emission lines could be obtained by the broad excitation band from the allowed 4f–5d absorption of Ce³⁺ ions. The intensity ratio of blue emission from Ce³⁺ and green emission from Tb³⁺ can be tuned by adjusting their concentrations. The energy transfer from Ce³⁺ to Tb³⁺ in NaCaBO₃ was found to be an electric dipole–quadrupole interaction.     

Visible Quantum Cutting and Energy Transfer in Tb3+‐Doped KSr(Gd,Y)(PO4)2 Under VUV–UV Excitation

KSr(Gd,Y)(PO₄)₂: Tb³⁺ phosphors were synthesized using the high‐temperature solid‐state reaction method. The VUV–UV spectroscopic properties of these phosphors were studied. The results show that efficient energy transfer (ET) from Gd³⁺ to Tb³⁺ occurs in this system, and the ET efficiency increases with increasing of Tb³⁺ doping concentrations, which is evidenced that both the emission intensity and decay time of Gd³⁺ decreases with increasing Tb³⁺ doping concentrations. Visible quantum cutting via cross relaxation between the neighboring Tb³⁺ ions was observed in the high Tb³⁺ concentration doped sample. In addition, the emission color of KSr(Gd,Y)(PO₄)₂: Tb³⁺ phosphors can be tuned from blue to yellowish‐green by varying the doping concentration of Tb³⁺. Under 147 nm excitation, the sample KSrGd_0.5(PO₄)₂: 0.5Tb³⁺ exhibits the strongest emission, which is about 70% of the commercial green‐emitting phosphor Zn₂SiO₄: Mn²⁺ indicating the potential application of this phosphor for plasma display panels, Hg‐free lamps, and three‐dimensional displays.     

Luminescence Properties and Energy Transfer of Ce3+,Tb3+‐Coactivatedβ‐SiAlON Phosphors

Using the solid‐state reaction method, Ce³⁺,Tb³⁺‐coactivated Si₅AlON₇ (Si_6?zAl_zO_zN_8?z, z = 1) phosphors were successfully synthesized. The obtained phosphors exhibit high absorption and strong excitation bands in the wavelength range of 240–440 nm, matching well with the light emitting‐diode (LED) chip. The ET from Ce³⁺ to Tb³⁺ ions in Si₅AlON₇:Ce³⁺,Tb³⁺ has been studied and demonstrated by the luminescence spectra and decay curves. Moreover, the phosphors show tunable emissions from blue to green by tuning the relative ratio of the Ce³⁺ to Tb³⁺ ions. Thermal quenching properties of Si₅AlON₇:Ce³⁺,Tb³⁺ had also been investigated and the quenching temperature is ~190°C. These results show that Si₅AlON₇:Ce³⁺,Tb³⁺ could be a promising candidate for a single‐phased color‐tunable phosphor applied in UV‐chip pumped LEDs.     

Multicolor Emission in a Single‐Phase Phosphor Ca3Al2O6:Ce3+,Li+: Luminescence and Site Occupancy

A single‐phase multicolor emitting phosphor, Ca₃Al₂O₆:Ce³⁺,Li⁺, was prepared by a solid‐state reaction. When the Ce³⁺ concentration is lower than 0.030 (molar ratio in Ca₃Al₂O₆), yellow and greenish blue emissions can be observed under the excitation by a blue and a near UV light, respectively. The yellow‐emitting phosphor possesses an internal quantum efficiency of 89%. Additional purplish blue emission turns up when Ce³⁺ concentrations are higher than 0.040. Tunable emission bands are originated from Ce³⁺ ions on different Ca sites in Ca₃Al₂O₆. Although the emission band of purplish blue or greenish blue overlaps the excitation band of yellow emission, and the distances between the unlike Ce³⁺ ions are in the range of electric dipole–dipole interaction, no energy transfer is observed. Furthermore, emission wavelengths for the yellow, greenish blue, and purplish blue emission show little change upon increasing Ce³⁺ concentrations.