Fracto‐mechanoluminescence and thermoluminescence properties of UV and γ‐irradiated Ca2Al2SiO7:Ce3+ phosphor

Ce³⁺‐doped calcium aluminosilicate phosphor was prepared by a combustion‐assisted method at an initiating temperature of 600°C. Structural characterization was carried out using X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The absorption spectra of Ca₂Al₂SiO₇:Ce³⁺ showed an absorption edge at 230 nm. The optical characterization of Ca₂Al₂SiO₇:Ce³⁺ phosphor was investigated in a fracto‐mechanoluminescence (FML) and thermoluminescence (TL) study. The peak of ML intensity increased as the height of impact of the moving piston increased. The TL intensity of Ca₂Al₂SiO₇:Ce³⁺ was recorded for different exposure times of UV and γ‐irradiation and it was observed that TL intensity was maximum for a UV irradiation time of 30 min and for a γ‐dose of 1180 Gy. The TL intensity had three peaks for UV irradiation at temperatures 82°C, 125°C and 203°C. Also the TL intensity had a single peak at 152°C for γ‐irradiation. The TL and ML emission spectra of Ca₂Al₂SiO₇:Ce³⁺ phosphor showed maximum emission at 400 nm. The possible mechanisms involved in the TL and ML processes of the Ca₂Al₂SiO₇:Ce³⁺ phosphor are also explained. Copyright © 2015 John Wiley & Sons, Ltd.     

Intense green‐, red‐emitting Tb3+, Tb3+/Bi3+‐doped and Sm3+, Sm3+/La3+‐doped Ca2Al2SiO7 phosphors

This paper focuses on an optical study of a Tb³⁺/Bi³⁺‐doped and Sm³⁺/La³⁺‐ doped Ca₂Al₂SiO₇ phosphor synthesized using combustion methods. Here, Ca₂Al₂SiO₇:Sm³⁺ showed a red emission band under visible light excitation but, when it co‐doped with La³⁺ ions, the emission intensity was further enhanced. Ca₂Al₂SiO₇:Tb³⁺ shows the characteristic green emission band under near‐ultraviolet light excitation wavelengths, co‐doping with Bi³⁺ ions produced enhanced photoluminescence intensity with better colour tunable properties. The phosphor exhibited better phase purity and crystallinity, confirmed by X‐ray diffraction. Binding energies of Ca(2p), Al(2p), Si(2p), O(1s) were studied using X‐ray photoelectron spectroscopy. The reported phosphor may be a promising visible light excited red phosphor for light‐emitting diodes and energy conversion devices.     

Structural characterization and optical properties of Ca2MgSi2O7:Eu2+,Dy3+ phosphor by solid‐state reaction method

Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphor was prepared by the solid‐state reaction method under a weak reducing atmosphere. The obtained phosphor was characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared (FT‐IR) techniques. The phase structure of the Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphor was akermanite type, which is a member of the melilite group. The surface morphology of the sintered phosphor was not uniform and phosphors aggregated tightly. EDX and FT‐IR spectra confirm the elements present in the Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphor. Under UV excitation, a broadband emission spectrum was found. The emission spectra observed in the green region centered at 535 nm, which is due to the 4f–5d transition. The mechanoluminescence (ML) intensity of the prepared phosphor increased linearly with increases in the mechanical load. The ML spectra were similar to the photoluminescence (PL), which indicates that ML is emitted from the same emitting center of Eu²⁺ ions as PL. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of UV irradiation on different types of luminescence of SrAl2O4:Eu,Dy phosphors

This paper reports the luminescence behavior of Sr_0.097Al₂O₄:Eu_0.01,Dy_0.02 phosphors under UV‐irradiation. The effect of UV‐irradiation on afterglow (AG), thermoluminescence (TL) and mechanoluminescence (ML) of Sr_0.097Al₂O₄:Eu_0.01,Dy_0.02 phosphors is investigated. The space group of Sr_0.097Al₂O₄:Eu_0.01,Dy_0.02 phosphors is monoclinic P2₁. The prepared phosphors exhibit a long AG, intense TL and ML. It is found that the AG, ML intensity and TL increase with increasing duration of irradiation time. The ML intensity decreases with successive impact of the load onto the phosphors, whereby the diminished ML intensity can be recovered by UV‐irradiation. Copyright © 2016 John Wiley & Sons, Ltd.     

Luminescence study and dosimetry approach of Ce on an α‐Sr2P2O7 phosphor synthesized by a high‐temperature combustion method

We report synthesis of a cerium‐activated strontium pyrophosphate (Sr₂P₂O₇) phosphor using a high‐temperature combustion method. Samples were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), photoluminescence (PL) and thermoluminescence (TL). The XRD pattern reveals that Sr₂P₂O₇ has an α‐phase with crystallization in the orthorhombic space group of Pnam. The IR spectrum of α‐Sr₂P₂O₇ displays characteristic bands at 746 and 1190 cm^‐1 corresponding to the absorption of (P₂O₇)^‐4. PL emission spectra exhibit a broad emission band around 376 nm in the near‐UV region due to the allowed 5d–4f transition of cerium and suggest its applications in a UV light‐emitting diode (LED) source. PL also reveals that the emission originates from 5d–4f transition of Ce³⁺ and intensity increases with doping concentration. TL measurements made after X‐ray irradiation, manifest a single intense glow peak at around 192°C, which suggests that this is an outstanding candidate for dosimetry applications. The kinetic parameters, activation energy and frequency factor of the glow curve were calculated using different analysis methods. Copyright © 2014 John Wiley & Sons, Ltd.     

Studies on the luminescence properties of cerium co‐doping on Ca2MgSi2O7:Eu2+ phosphor by solid‐state reaction method

Ca₂MgSi₂O₇:Ce³⁺, Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺,Ce³⁺ phosphors were prepared using the solid‐state reaction method. The crystal structures of the sintered phosphors were of melilite type, which has a tetragonal crystallography. The chemical compositions of the sintered phosphors was confirmed by energy dispersive X‐ray spectroscopy. The different thermoluminescence kinetic parameters [activation energy (E), frequency factor (s) and order of the kinetics (b)] of these phosphors were evaluated and compared using the peak shape method. Under ultraviolet excitation, the emission spectra of both Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺,Ce³⁺ phosphors were composed of a broad emission band peaking at 530 nm. When the Ca₂MgSi₂O₇:Eu²⁺ phosphor is co‐doped with Ce³⁺ ions, photoluminescence, afterglow and mechanoluminescence intensity was strongly enhanced. Ca₂MgSi₂O₇:Eu²⁺ showed some afterglow with a short persist time. On incorporation of Ce³⁺, efficient energy transfer from Ce³⁺ to Eu²⁺ was found and the emission intensity of Eu²⁺ was enhanced. The mechanoluminescence intensities of Ca₂MgSi₂O₇:Ce³⁺, Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺,Ce³⁺ phosphors increased proportionally increased with the increase in impact velocity, which suggests that these phosphors can be used as sensors to detect stress in an object.     

Thermoluminescence and photoluminescence studies on γ‐ray‐irradiated Ce3+,Tb3+‐doped potassium chloride single crystals

Single crystals of KCl doped with Ce³⁺,Tb³⁺ were grown using the Bridgeman–Stockbarger technique. Thermoluminescence (TL), optical absorption, photoluminescence (PL), photo‐stimulated luminescence (PSL), and thermal‐stimulated luminescence (TSL) properties were studied after γ‐ray irradiation at room temperature. The glow curve of the γ‐ray‐irradiated crystal exhibits three peaks at 420, 470 and 525 K. F‐Light bleaching (560 nm) leads to a drastic change in the TL glow curve. The optical absorption measurements indicate that F‐ and V‐centres are formed in the crystal during γ‐ray irradiation. It was attempted to incorporate a broad band of cerium activator into the narrow band of terbium in the KCl host without a reduction in the emission intensity. Cerium co‐doped KCl:Tb crystals showed broad band emission due to the d–f transition of cerium and a reduction in the intensity of the emission peak due to ⁵D₃–⁷F_j (j = 3, 4) transition of terbium, when excited at 330 nm. These results support that energy transfer occurs from cerium to terbium in the KCl host. Co‐doping Ce³⁺ ions greatly intensified the excitation peak at 339 nm for the emission at 400 nm of Tb³⁺. The emission due to Tb³⁺ ions was confirmed by PSL and TSL spectra. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescence properties of green‐emitting Ca2MgSi2O7:Eu2+ phosphor by a solid‐state reaction method

A europium (Eu)‐doped di‐calcium magnesium di‐silicate phosphor, Ca₂MgSi₂O₇:Eu²⁺, was prepared using a solid‐state reaction method. The phase structure, particle size, surface morphology, elemental analysis, different stretching mode and luminescence properties were analyzed by X‐ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) with energy dispersive X‐ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) and mechanoluminescence (ML). The phase structure of Ca₂MgSi₂O₇:Eu²⁺ was an akermanite‐type structure, which belongs to the tetragonal crystallography with space group P4?2₁m; this structure is a member of the melilite group and forms a layered compound. The surface of the prepared phosphor was not found to be uniform and particle distribution was in the nanometer range. EDX and FTIR confirm the components of Eu²⁺‐doped Ca₂MgSi₂O₇ phosphor. Under UV excitation, the main emission peak appeared at 530 nm, belonging to the broad emission ascribed to the 4f⁶5d¹→4f⁷ transition of Eu²⁺. The ML intensity of the prepared phosphor increased linearly with increasing impact velocity. A CIE color chromaticity diagram and ML spectrum confirmed that the prepared Ca₂MgSi₂O₇:Eu²⁺ phosphor would emit green color and the ML spectrum was similar to that of PL, which indicated that ML is emitted from the same center of Eu²⁺ ions. Copyright © 2015 John Wiley & Sons, Ltd.     

Thermoluminescence properties of Eu‐doped and Eu/Dy‐codoped Sr2Al2SiO7 phosphors

We report the thermoluminescence properties of Sr_1.96Al₂SiO₇:Eu_0.04 and Sr_1.92Al₂SiO₇:Eu_0.04Dy_0.04 phosphors. These phosphors were prepared by a high‐temperature solid‐state reaction method. The prepared phosphors were characterized by X‐ray diffraction. A 254 nm source was used for ultraviolet (UV) irradiation and a ⁶⁰Co source was used for γ‐irradiation. The effect of heating rate and UV‐exposure were examined. The thermoluminescence temperature shifts to higher values with increasing heating rate and thermoluminescence intensity increases with increasing UV exposure time. The trapping parameters such as activation energy (E), order of kinetics and frequency factor (s) were calculated by peak shape method. The effect of γ‐ and UV‐irradiation on thermoluminescence studies was also examined.     

Mechanoluminescence,thermoluminescence, photoluminescence studies on Ca3Y2Si3O12:RE3+ (RE3+ = Dy3+and Eu3+) phosphors

Dy³⁺ and Eu³⁺ activated Ca₃Y₂Si₃O₁₂ phosphors were synthesized by the solid‐state synthesis method. The phosphors were characterized by X‐ray diffraction (XRD), mechanoluminescence (ML), thermoluminescence (TL) and photoluminescence (PL) to determine structure and luminescence. For ML glow curves, only one peak was observed, as only one type of luminescence centre was formed during irradiation. The Ca₃Y₂Si₃O₁₂:Dy³⁺ TL glow curve showed a single peak at 151.55°C and the Ca₃Y₂Si₃O₁₂:Eu³⁺ TL glow curve peaked at 323°C with a small peak at 192°C, indicating that two types of traps were activated. The trapping parameters for both the samples were calculated using Chen's peak shape method. Dy³⁺‐activated Ca₃Y₂Si₃O₁₂ showed emission at 482 and 574 nm when excited by a 351 nm excitation wavelength, whereas the Eu³⁺‐activated Ca₃Y₂Si₃O₁₂ phosphor PL emission spectra showed emission peaks at 613 nm, 591 nm, 580 nm when excited at 395 nm wavelength. When excited at 466 nm, prominent emission peaks were observed at their respective positions with very slight shifts. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescence and energy‐transfer properties of color‐tunable Ca2Mg0.25Al1.5Si1.25O7:Ce3+/Eu2+/Tb3+ phosphors for ultraviolet light‐emitting diodes

A series of Ca₂Mg_0.25Al_1.5Si_1.25O₇:Ce³⁺/Eu²⁺/Tb³⁺ phosphors was been prepared via a conventional high temperature solid‐state reaction and their luminescence properties were studied. The emission spectra of Ca₂Mg_0.25Al_1.5Si_1.25O₇:Ce³⁺,Eu²⁺ and Ca₂Mg_0.25Al_1.5Si_1.25O₇:Ce³⁺,Tb³⁺ phosphors show not only a band due to Ce³⁺ ions (409 nm) but also as a band due to Eu²⁺ (520 nm) and Tb³⁺ (542 nm) ions. More importantly, the effective energy transfer from Ce³⁺ to Eu²⁺ and Tb³⁺ ions was confirmed and investigated by emission/excitation spectra and luminescent decay behaviors. Furthermore, the energy level scheme and energy transfer mechanism were investigated and were demonstrated to be of resonant type via dipole–dipole (Ce³⁺ to Eu²⁺) and dipole–quadrupole (Ce³⁺ to Tb³⁺) reactions, respectively. Under excitation at 350 nm, the emitting color could be changed from blue to green by adjusting the relative doping concentration of Ce³⁺ and Eu²⁺ ions as well as Ce³⁺ and Tb³⁺ ions. The above results indicate that Ca₂Mg_0.25Al_1.5Si_1.25O₇:Ce³⁺,Eu²⁺/Tb³⁺ are promising single‐phase blue‐to‐green phosphors for application in phosphor conversion white‐light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescent properties of Ca3SiO4Cl2 co‐doped with Ce3+ and Eu2+ for near‐ultraviolet light‐emitting diodes

Ca₃SiO₄Cl₂ co‐doped with Ce³⁺,Eu²⁺ was prepared by high temperature reaction. The structure, luminescent properties and the energy transfer process of Ca₃SiO₄Cl₂: Ce³⁺,Eu²⁺ were investigated. Eu²⁺ ions can give enhanced green emission through Ce³⁺ → Eu²⁺ energy transfer in these phosphors. The green phosphor Ca_2.9775SiO₄Cl₂:0.0045Ce³⁺,0.018Eu²⁺ showed intense green emission with broader excitation in the near‐ultraviolet light range. A green light‐emitting diode (LED) based on this phosphor was made, and bright green light from this green LED could be observed by the naked eye under 20 mA current excitation. Hence it is considered to be a good candidate for the green component of a three‐band white LED. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescence characteristics of Na3Ca2(SO4)3F: Ce3+ fluoride material

A new Na₃Ca₂(SO₄)₃F: Ce³⁺ phosphor synthesized by a solid state diffusion method is reported. The photoluminescence study showed a single high intensity emission peak at 307 nm wavelength when excited by UV light of wavelength 278 nm. An unresolved peak of comparatively less intensity was also observed at 357 nm along with the main peak. The characteristic emission of dopant Ce in Na₃Ca₂(SO₄)₃F phosphor clearly indicated that it resides in the host lattice in trivalent form. The emission peak can be attributed to 5d → 4f transition of rare earth Ce³⁺. The prepared sample is also characterized for its thermoluminescence properties. The TL glow curve of prepared sample showed a single broad peak at 147°C. The trapping parameters are also evaluated by Chen's method. The values of trap depth (E) and frequency factor (s) were found to be 0.64 ± 0.002 eV and 1.43 × 10⁷ s^–1 respectively. The study of PL and TL along with evaluation of trapping parameters has been undertaken and discussed for the first time. Copyright © 2014 John Wiley & Sons, Ltd.     

Design,synthesis and luminescence properties of Ba2YB2O6Cl‐ and Ba2YB2O6F‐based phosphors

Using a high‐temperature solid‐state reaction, the chlorine in Ba₂YB₂O₆Cl is gradually replaced by F, and a new compound with the nominal chemical formula Ba₂YB₂O₆F and two phosphors doped with Ce³⁺ and Eu³⁺, respectively, are obtained. X‐Ray diffraction and photoluminescence spectroscopy are used to characterize the as‐synthesized samples. The as‐synthesized Ba₂YB₂O₆Cl exhibits bright blue emission in the spectral range ~ 330–410 nm with a maximum around 363 nm under X‐ray or UV excitation. Ba₂YB₂O₆F:0.01Ce³⁺ exhibits blue emission in the range ~ 340–570 nm with a maximum around 383 nm. Ba₂YB₂O₆F:0.01Eu³⁺ exhibits a predominantly ⁵D₀–⁷ F₂ emission (~610 nm) and the relative intensities of the ⁵D₀–⁷ F_0,1,2 emissions are tunable under different wavelength UV excitation. The luminescence behaviors of the two phosphors are explained simply in terms of the host composition and site occupancy probability of Ce³⁺ and Eu³⁺, respectively. The results indicate that these phosphors have potential application as a blue phosphor or as a red phosphor. Copyright © 2014 John Wiley & Sons, Ltd.     

Optical properties and energy transfer of Eu2+/Ce3+ co‐activated Na3Ca6(PO4)5 phosphor

Ce³⁺/Eu²⁺ co‐doped Na₃Ca₆(PO₄)₅ phosphors were prepared using a combustion‐assisted synthesis method. X‐Ray powder diffraction (XRD) analysis confirmed the formation of a Na₃Ca₆(PO₄)₅ crystal phase. Na₃Ca₆(PO₄)₅:Eu²⁺ phosphors have an efficient bluish‐green emission band that peaks at 489 nm, whereas Ce³⁺‐doped Na₃Ca₆(PO₄)₅ showed a bright emission band at 391 nm. Analysis of the experimental results suggests that enhancement of the Eu²⁺ emission intensity in co‐doped Na₃Ca₆(PO₄)₅:Eu²⁺,Ce³⁺ phosphors is due to a resonance‐type energy transfer from Ce³⁺ to Eu²⁺ ions, which is predominantly governed by an exchange interaction mechanism. These results indicate that Ce³⁺/Eu²⁺ co‐doped Na₃Ca₆(PO₄)₅ is potentially useful as a highly efficient, bluish‐green emitting, UV‐convertible phosphor for white‐light‐emitting diodes. Copyright © 2014 John Wiley & Sons, Ltd.     

Role of Li+ ions on the surface morphology and thermoluminescence properties of Y2O3:Tm3+ nanophosphor

Y₂O₃:Tm³⁺ and Li⁺ co‐doped Y₂O₃:Tm³⁺ nanopowders were synthesized using the solution combustion method for possible application in ultraviolet (UV) light dosimetry. X‐ray diffraction revealed the crystallite sizes to be in the range 21–44 nm and 30–121 nm using the Scherrer equation and the W‐H plot relationship, respectively. Field emission scanning electron microscopy confirmed that, after co‐doping with 4 mol% concentration of Li⁺, the particles were spherical in nature with an average size of ~30 nm. Fourier transformed infrared spectroscopy results showed bands at wavenumbers of 556, 1499, 1704, 2342, 2358, 2973, 3433, and 3610 cm^?1 that corresponded to the stretching and bending vibrations of Y–O, C=O and O–H. Thermoluminescence (TL) glow peaks for Y₂O₃:Tm³⁺ nanophosphors observed at 399 and 590 K were attributed to oxygen defects caused using UV irradiation. These oxygen defects firstly resulted in an increased prominent peak TL intensity for up to 270 min of irradiation and then a decrease. This was attributed to the presence of oxygen defect clusters that caused a reduction in recombination centres. The Li⁺ co‐doped sample showed peaks at 356, 430, and 583 K and its intensity sublinearly increased up to 90 min and then thereafter decreased. The TL trapping parameters were calculated using computerized glow curve deconvolution methods. The Li⁺ co‐doped sample exhibited less fading and high trap density under the UV radiation.     

Effect of Dy3+ or Eu2+ co‐activator on a BaCa(SO4)2:Ce3+ mixed alkaline earth sulfate phosphor

The individual emission and energy transfer between Ce³⁺ and Eu²⁺ or Dy³⁺ in BaCa(SO₄)₂ mixed alkaline earth sulfate phosphor prepared using a co‐precipitation method is described. The phosphor was characterized by X‐ray diffraction (XRD) and photoluminescence (PL) studies and doped by Ce;Eu and Dy rare earths. All phosphors showed excellent blue–orange emission on excitation with UV light. PL measurements reveal that the emission intensity of Eu²⁺ or Dy³⁺ dopants is greater than when they are co‐doped with Ce³⁺. An efficient Ce³⁺ → Eu²⁺ [²T_2g(4f⁶5d) → ⁸S_7/2(4f₇)] and Ce³⁺ → Dy³⁺ (⁴ F_9/2 → ⁶H_15/2 and ⁴ F_9/2 → ⁶H_13/2) energy transfer takes place in the BaCa(SO₄)₂ host. A strong blue emission peak was observed at 462 nm for Eu²⁺ ions and an orange emission peak at 574 nm for Dy³⁺ ions. Hence, this phosphor may be used as a lamp phosphor. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of Ce doping on the luminescent property of Ca3SiO4Cl2:Eu phosphor for green lighting

White light‐emitting diodes (LEDs) for green lighting are new solutions for energy saving and environmental protection. Ca₃SiO₄Cl₂:Ce,Eu is an efficient phosphor for white LEDs. Effective energy transfer from Ce³⁺ to Eu²⁺ occurs in Ca₃SiO₄Cl₂:Ce,Eu due to good spectrum overlap between the emission band of Ca₃SiO₄Cl₂:Ce and the excitation band of Ca₃SiO₄Cl₂:Eu, and hues vary systematically from blue to green at different Ce concentrations. A great improvement in the luminescent property of Ca₃SiO₄Cl₂:Eu has been observed on Ce³⁺ doping, which is attributed to energy transfer from Ce³⁺ to Eu²⁺ and an increase in the number of luminescent centers (Eu²⁺) on Ce doping. The optimal sample has a quantum efficiency of up to 75%, and can be an efficient green phosphor for white LEDs. Copyright © 2014 John Wiley & Sons, Ltd.     

Characterization and luminescence properties of CaMgSi2O6:Eu2+ blue phosphor

A blue CaMgSi₂O₆:Eu²⁺ phosphor was prepared by the solid‐state reaction method and the phosphor characterized in terms of crystal structure, particle size, photoluminescence (PL), thermoluminescence (TL) and mechanoluminescence (ML) properties using X‐ray diffraction (XRD), transmission electron microscopy (TEM), PL spectroscopy, TLD reader and ML impact technique. The XRD result shows that phosphor is formed in a single phase and has a monoclinic structure with the space group C2/c. Furthermore, the PL excitation spectra of Eu²⁺‐doped CaMgSi₂O₆ phosphor showed a strong band peak at 356 nm and the PL emission spectrum has a peak at 450 nm. The depths and frequency factors of trap centers were calculated using the TL glow curve by deconvolution method in which the trap depths were found to be 0.48 and 0.61 eV. The formation of CaMgSi₂O₆:Eu²⁺ phosphor was confirmed by Fourier transform infrared spectroscopy. The ML intensity increased linearly with the impact velocity of the piston used to deform the phosphor. It was shown that the local piezoelectricity‐induced electron bombardment model is responsible for the ML emission. Finally, the optical properties of CaMgSi₂O₆:Eu²⁺ phosphors are discussed. Copyright © 2015 John Wiley & Sons, Ltd.     

Photoluminescence properties of Ca2Al2O5:RE3+ (RE = Eu,Dy and Tb) phosphors for solid state lighting

Ca₂Al₂O₅:Eu³⁺, Ca₂Al₂O₅:Dy³⁺ and Ca₂Al₂O₅:Tb³⁺ phosphors were synthesized using a combustion synthesis method. The prepared phosphors were characterized by X‐ray powder diffraction for phase purity, by scanning electron microscopy for morphology, and by photoluminescence for emission and excitation measurements. The Ca₂Al₂O₅:Eu³⁺ phosphors could be efficiently excited at 396 nm and showed red emission at 594 nm and 616 nm due to ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions. Dy³⁺‐doped phosphors showed blue emission at 482 nm and yellow emission at 573 nm. Ca₂Al₂O₅:Tb³⁺ phosphors showed emission at 545 nm when excited at 352 nm. Concentration quenching occurred in both Eu³⁺ and Dy³⁺phosphors at 0.5 mol%. Photoluminescence results suggested that the aluminate‐based phosphor could be a potential candidate for application in environmentally friendly based lighting technologies.