Insights into the discrepant luminescence for BaSiO3:Eu2+ phosphors prepared by solid‐state reaction and precipitation reaction methods

Two synthesis routes, solid‐state reaction and precipitation reaction, were employed to prepare BaSiO₃:Eu²⁺ phosphors in this study. Discrepancies in the luminescence green emission at 505 nm for the solid‐state reaction method sample and in the yellow emission at 570 nm for the sample prepared by the precipitation reaction method, were observed respectively. A detail investigation about the discrepant luminescence of BaSiO₃:Eu²⁺ phosphors was performed by evaluation of X‐ray diffraction (XRD), photoluminescence (PL)/photoluminescence excitation (PLE), decay time and thermal quenching properties. The results showed that the yellow emission was generated from the BaSiO₃:Eu²⁺ phosphor, while the green emission was ascribed to a small amount of Ba₂SiO₄:Eu²⁺ compound that was present in the solid‐state reaction sample. This work clarifies the luminescence properties of Eu²⁺ ions in BaSiO₃ and Ba₂SiO₄ hosts.     

Luminescence behavior of Li2Sr1‐3x/2EuxSiO4 red phosphors for LED applications

Red‐emitting Li₂Sr_1‐3x/2Eu_xSiO₄ 0≤x≤0.5) phosphors were synthesized at 900°C in air by a solid‐state reaction. The synthesized phosphors were characterized by X‐ray powder diffraction, photoluminescence (PL) excitation (PLE) and PL spectra. The results from the PLE spectra suggest that the strong 394 nm excitation peak associated with the ⁵L₆ state of Eu³⁺ ions is of significance for near ultraviolet pumped white light‐emitting diodes and solid‐state lighting. It is also noted that the position of the charge transfer state of Eu³⁺ ions shifts towards the higher energy side (blue shift) by increasing the content of Eu³⁺ ions. The predominant emissions of Eu³⁺ ions under 394 nm excitation are observed at 580, 593, 614, 656 and 708 nm, which are attributed to the ⁵D₀ → ⁷F_J (J = 0, 1, 2, 3 and 4), respectively. The PL results reveal that the optimal content of the red‐emitting Li₂Sr_1‐3x/2Eu_xSiO₄ phosphors is x = 0.475. Simulation of the white light excited by 394 nm near ultraviolet light has also been carried out for its potential white light‐emitting diode applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Tunable white light emission from single‐phased Li2SrSiO4:Dy3+ phosphors by co‐doping with Eu3+

A series of single‐phase full‐color emitting Li₂Sr_1−x−ySiO₄:xDy³⁺,yEu³⁺ phosphors were synthesized by solid‐state reaction and characterized by X‐ray diffraction and photoluminescence analyses. The samples showed emission peaks at 488 nm (blue), 572 nm (yellow), 592 nm (orange) and 617 nm (red) under 393 nm excitation. The photoluminescence excitation spectra, comprising the Eu–O charge transfer band and 4f–4f transition bands of Dy³⁺ and Eu³⁺, range from 200 to 500 nm. The Commission Internationale de I'Eclairage chromaticity coordinates for Li₂Sr_0.98−xSiO₄:0.02Dy³⁺,xEu³⁺ phosphors were simulated. By manipulating Eu³⁺ and Dy³⁺ concentrations, the color points of Li₂Sr_1−x−ySiO₄:xDy³⁺,yEu³⁺ were tuned from the greenish‐white region to white light and eventually to reddish‐white region, demonstrating that a tunable white light can be obtained by Li₂Sr_1−x−ySiO₄:xDy³⁺,yEu³⁺ phosphors. Li₂Sr_0.98−xSiO₄:0.02Dy³⁺, xEu³⁺ can serve as a white‐light‐emitting phosphor for phosphor‐converted light‐emitting diode. Copyright © 2014 John Wiley & Sons, Ltd.     

Impact of temperature on Na2Sr(PO4)F:Eu3+ phosphor

In this article, we report the synthesis of Na₂Sr_1‐x(PO₄)F:Eu_x phosphor via a combustion method. The influence of different annealing temperatures on the photoluminescence properties was investigated. The phosphor was excited at both 254 and 393 nm. Na₂Sr_1‐x(PO₄)F:Eu_x³⁺ phosphors emit strong orange and red color at 593 and 612 nm, respectively, under both excitation wavelengths. Na₂Sr_1‐x(PO₄)F:Eu_x³⁺ phosphors annealed at 1050°C showed stronger emission intensity compared with 600, 900 and 1200°C. Moreover, Na₂Sr_1‐x(PO₄)F:Eu_x³⁺ phosphor was found to be more intense when compared with commercial Y₂O₃:Eu³⁺ phosphor. Copyright © 2013 John Wiley & Sons, Ltd.     

Enhancement of the luminescence properties of Sr3(PO4)2:Dy3+,Li+ white‐light‐emitting phosphors by charge compensator Li+ co‐doping

Sr₃(PO₄)₂:Dy³⁺,Li⁺ phosphors were prepared using a simple high temperature solid method for luminescence enhancement. The structures of the as‐prepared samples agreed well with the standard phase of Sr₃(PO₄)₂, even when Dy³⁺ and Li⁺ were introduced. Under ultraviolet excitation at 350 nm, the Sr₃(PO₄)₂:Dy³⁺ sample exhibited two emission peaks at 483 nm and 580 nm, which were due to the ⁴F_9/2 → ⁶H_15/2 and ⁴F_9/2 → ⁶H_13/2 transitions of Dy³⁺ ions, respectively. A white light was fabricated using these two emissions from the Sr₃(PO₄)₂:Dy³⁺ phosphors. The luminescence properties of Sr₃(PO₄)₂:Dy³⁺,Li⁺ phosphors, including emission intensity and decay time, were improved remarkably with the addition of Li⁺ as the charge compensator, which would promote their application in near‐ultraviolet excited white‐light‐emitting diodes.     

Luminescent properties of sol–gel processed red‐emitting phosphor Ca0.6Sr0.4–1.5x‐0.5yMo0.4 W0.6O4:EuxLiy

A series of red‐emitting phosphors Ca_0.6Sr_{0.4–1.5x‐0.5y}Mo_0.4 W_0.6O₄:Eu_xLi_y (x = 0.02–0.12, y = 0–0.12) has been synthesized by a sol‐gel method. The effects of calcining temperature, concentrations of Li⁺ and Eu³⁺, and compensation ions on the luminescent properties were investigated. X‐ray diffraction and scanning electron microscopic results showed that as‐prepared phosphors were of single phase with several microns. The Li⁺ compensated compositions showed remarkably intense red emission at 619 nm. The emission intensity of the series reached maximum for compositions at x = 0.08 and y = 0.08 when the calcining temperature was 900 °C. Copyright © 2014 John Wiley & Sons, Ltd.     

The luminescent properties and crystal structure of Sr(1.5‐x)‐(1.5y)Mg0.5SiO4:xEu2+,yCe3+ blue phosphor synthesized by co‐precipitation method

In order to improve the luminescent performance of silicate blue phosphors, Sr_{(1.5‐x)‐(1.5y)}Mg_0.5SiO₄:xEu²⁺,yCe³⁺ phosphors were synthesized using one‐step calcination of a precursor prepared by chemical co‐precipitation. The crystal structure and luminescent properties of the phosphors were analyzed using X‐ray diffraction and fluorescence spectrophotometry, respectively. Because the activated ions (Eu²⁺) can occupy two different types of sites (Sr₁ and Sr₂), the emission spectrum of Eu²⁺ excited at 350 nm contains two single bands (EM₁ and EM₂) in the wavelength range 400–550 nm, centered at 463 nm, and the emission intensity first increases and then decreases with increasing concentrations of Eu²⁺ ions. Co‐doping of Ce³⁺ ions can greatly enhance the emission intensity of Eu²⁺ by transferring its excitation energy to Eu²⁺. Because of concentration quenching, a higher substitution concentration of Ce³⁺ can lead to a decrease in the intensity. Meanwhile, the quantum efficiency of the phosphor is improved after doping with Ce³⁺, and a blue shift phenomenon is observed in the CIE chromaticity diagram. The results indicate that Sr_{(1.5‐x)‐(1.5y)}Mg_0.5SiO₄:xEu²⁺,yCe³⁺ can be used as a potential new blue phosphor for white light‐emitting diodes.     

Microwave‐assisted sintering synthesis of greenish‐yellow emitting Sr2SiO4:Eu2+ phosphors

Europium ion (Eu²⁺) doped Sr₂SiO₄ phosphors with greenish‐yellow emission were synthesized using microwave‐assisted sintering. The phase structure and photoluminescence (PL) properties of the obtained phosphor samples were investigated. The PL excitation spectra of the Sr₂SiO₄:Eu²⁺ phosphors exhibited a broad band in the range of 260 nm to 485 nm with a maximum at 361 nm attributed to the 5f‐4d allowed transition of the Eu²⁺ ions. Under an excitation at 361 nm, the Sr₂SiO₄:Eu²⁺ phosphor exhibited a greenish‐yellow emission peak at 541 nm with an International‐Commission‐on‐Illumination (CIE) chromaticity of (0.3064, 0.4772). The results suggest that the microwave‐assisted sintering method is promising for the synthesis of phosphors owing to the decreased sintering time without the use of additional reductive agents.     

Sol–gel preparation and luminescent properties of red‐emitting phosphor Sr‐Ba‐Mo‐W‐O‐(Eu3+,Sm3+)

Two series of red‐emitting phosphors Sr‐Ba‐Mo‐W‐O:Eu,Sm and Sr‐Ba‐Mo‐W‐O:Eu have been synthesized by a sol–gel method. The effects of the chemical composition, concentrations of Sm³⁺ and Eu³⁺, the Sr²⁺/Ba²⁺ ratio, and the W⁶⁺/Mo⁶⁺ ratio on the luminescent properties were investigated. The as‐prepared phosphors were characterized by X‐ray diffraction and Raman spectra. Results showed that single phases of the two series were prepared. The compositions of Sr_0.6Ba_0.13Mo_0.8 W_0.2O₄:Eu_0.10Sm_0.08 and Sr_0.75Ba_0.1Mo_0.8 W_0.2O₄:Eu_0.10 had the strongest luminescent intensity. The excitation spectra of Sm³⁺, Eu³⁺ co‐doped phosphors were broader and the strongest peak moved to 404 nm when compared with that of Eu³⁺ single‐doped phosphors. The luminescent intensity of the Sr_0.6Ba_0.13Mo_0.8 W_0.2O₄:Eu_0.10Sm_0.08 at 618 nm were 2.8 times greater than that of Sr_0.75Ba_0.1Mo_0.8 W_0.2O₄:Eu_0.10. The luminescent intensity of Sr_0.6Ba_0.13Mo_0.8 W_0.2O₄:Eu_0.10Sm_0.08 and Sr_0.75Ba_0.1Mo_0.8 W_0.2O₄:Eu_0.10 at 150 °C decreased to 56.8% and 50.3% of the initial value at room temperature, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Novel pure Ca2ZnMoO6 composition with white‐light luminescence

Phosphors with composition Ca₂ZnMoO₆ were synthesized at temperatures of 800–1200°C using the solid‐state method. Analysis of X‐ray diffraction patterns of the Ca₂ZnMoO₆ powders did not reveal a double perovskite structure. When the synthesis temperature was equal to or higher than 800°C, the synthesized Ca₂ZnMoO₆ powders revealed a tetragonal structure (CaMoO₄) rather than an orthorhombic structure (Ca₂ZnMoO₆) and the cubic structure (Sr₂ZnMoO₆) of a double perovskite. The ZnO phase was still observed at a synthesis temperature of 1200°C. The compositions of synthesized Ca₂ZnMoO₆ powders differed from the prepared powder, and the Ca₂ZnMoO₆ phosphors exhibited some important novel features. First, synthesized Ca₂ZnMoO₆ compositions could emit light as a phosphor no activators, called Ca₂ZnMoO₆ phosphors. Effect of synthesis temperature on luminescence properties of these Ca₂ZnMoO₆ phosphors was readily observed, and some important novel features and properties were noted. Second, the phosphors presented only one broad characteristic emission peak in the visible light region. Third, measurement of the chromaticity diagram of the Ca₂ZnMoO₆ phosphors revealed a white‐light source. Through analysis, we determined why the synthesized Ca₂ZnMoO₆ phosphors had just one broad characteristic emission peak.     

Luminescent properties of novel red‐emitting M7Sn(PO4)6:Eu3+ (M = Sr,Ba) for light‐emitting diodes

Novel red‐emitting phosphors, Eu³⁺‐activated M₇Sn(PO₄)₆ (M = Sr, Ba), were synthesized at 1200°C by conventional solid‐state reaction method. The luminescent properties of M₇Sn(PO₄)₆:Eu³⁺ (M = Sr, Ba) phosphors were investigated, and the critical concentration of the activator (Eu³⁺) concentration were found to be 0.175 mol and 0.21 mol per formula unit for Sr_7‐xSn(PO₄)₆:xEu³⁺ and Ba_7‐xSn(PO₄)₆:xEu³⁺, respectively. These phosphors presented red luminescence under the excitation of 395 or 465 nm, perfectly matching with the emissions wavelength of near‐ultraviolet (UV) light‐emitting diodes (LEDs) and InGaN blue LED.     

Synthesis and luminescence properties of a blue-emitting Sr(3.5) Y(6.5) O(2) (PO(4) )(1.5) (SiO(4) )(4.5) :Eu(2+) phosphor

A novel blue‐emitting Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:Eu²⁺ phosphor was synthesized via a solid‐state reaction. Powder X‐ray diffraction (XRD) analysis demonstrated that the Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5 host had a hexagonal crystal structure in the space group P6₃/m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as‐prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20–250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as‐prepared Sr_3.45Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:0.05Eu²⁺ phosphor was determined to be 0.20 eV. Copyright © 2011 John Wiley & Sons, Ltd.     

Sr2ZnWO6:Eu3+,Bi3+,Li+: a potential white‐emitting phosphor for near‐ultraviolet white light‐emitting diodes

A series of Sr₂ZnWO₆ phosphors co‐doped with Eu³⁺, Bi³⁺ and Li⁺ were prepared using the Pechini method. The samples were tested using X‐ray diffraction and luminescence spectroscopy. The results show that the samples can be effectively excited by near‐ultraviolet (UV) and UV light. The introduction of Bi³⁺ and Li⁺ significantly enhances the fluorescence emission of Sr₂ZnWO₆:Eu³⁺ and changes the light emitted by the phosphors from bluish‐green to white. When excited at 371 nm, Sr_2–x–zZn_1–yWO₆:xEu³⁺,yBi³⁺,zLi⁺ (x = 0.05, y = 0.05, z = 0.05, 0.1 and 0.15) samples emit high‐performance white light. Intense red–orange emission is also observed when excited by UV light. The obtained phosphor is a potential white‐emitting phosphor that could meet the needs of excitation sources with near‐UV chips. In addition, this phosphor might have promising application as a red–orange emitting phosphor for white light‐emitting diodes based on UV light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.     

Luminescence enhancement of (Sr1–xMx)2SiO4:Eu2+ phosphors with M (Ca2+/Zn2+) partial substitution for white light‐emitting diodes

Eu²⁺‐doped Sr₂SiO₄ phosphor with Ca²⁺/Zn²⁺ substitution, (Sr_1–xM_x)₂SiO₄:Eu²⁺ (M = Ca, Zn), was prepared using a high‐temperature solid‐state reaction method. The structure and luminescence properties of Ca²⁺/Zn²⁺ partially substituted Sr₂SiO₄:Eu²⁺ phosphors were investigated in detail. With Ca²⁺ or Zn²⁺ added to the silicate host, the crystal phase could be transformed between the α‐form and the β‐form of the Sr₂SiO₄ structure. Under UV excitation at 367 nm, all samples exhibit a broad band emission from 420 to 680 nm due to the 4f⁶5d¹ → 4f⁷ transition of Eu²⁺ ions. The broad emission band consists of two peaks at 482 and 547 nm, which correspond to Eu²⁺ ions occupying the ten‐fold oxygen‐coordinated Sr.(I) site and the nine‐fold oxygen‐coordinated Sr.(II) site, respectively. The luminescence properties, including the intensity and lifetime of Sr₂SiO₄:Eu²⁺ phosphors, improved remarkably on Ca²⁺/Zn²⁺ addition, and promote its application in white light‐emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and luminescent properties of novel BaGd2O4:Eu3+ scintillating phosphor

BaGd_2‐xO₄:xEu³⁺ and Ba_1‐yGd_1.79‐2yEu_0.21Na_3yO₄ phosphors were synthesized at 1300°C in air by conventional solid‐state reaction method. Phosphors were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence excitation (PLE) spectra, photoluminescence (PL) spectra and thermoluminescence (TL) spectra. Optimal PL intensity for BaGd_2‐xO₄:xEu³⁺ and Ba_1‐yGd_1.79‐2yEu_0.21Na_3yO₄ phosphors at 276 nm excitation were found to be x = 0.24 and y = 0.125, respectively. The PL intensity of Eu³⁺ emission could only be enhanced by 1.3 times with incorporation of Na⁺ into the BaGd₂O₄ host. Enhanced luminescence was attributed to the flux effect of Na⁺ ions. However, when BaGd₂O₄:Eu³⁺ phosphors were codoped with Na⁺ ions, the induced defects confirmed by TL spectra impaired the emission intensity of Eu³⁺ ions. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of Mg doping in Sr2SiO4:Eu2+ nanophosphors for blue and white emission at near‐UV excitation

Nanophosphors of (Sr_0.98‐xMg_xEu_0.02)₂SiO₄ (x = 0, 0.18, 0.38, 0.58 and 0.78) were prepared through low temperature solution combustion method and their luminescence properties were studied. The emission peak for Eu²⁺ ?doped Sr₂SiO₄ nanophosphor is observed at ~490 nm and ~553 nm corresponding to two Sr²⁺ sites Sr(I) and Sr(II) respectively for 395 nm excitation. However the addition of Mg²⁺ dopant in Sr₂SiO₄ leads to suppression of ~553 nm emission peak due to absence of energy levels of Sr (II) sites which results in a single broad emission at ~460 nm. It was shown that the emission peak blue shifted with increase in Mg concentration which may be attributed to change in crystal field environment around Sr(I) sites. Therefore, the (Mg_0.78Sr_0.20Eu_0.02)₂SiO₄ nanophosphor can be used for blue emission and the Sr₂SiO₄:Eu_0.04²⁺ for green–yellow emission at 395 nm excitations. The Commission International de L'Eclairage (CIE) chromaticity coordinates for mixed powders of (Mg_0.78Sr_0.20Eu_0.02)₂SiO₄ and Sr₂SiO₄:Eu_0.04²⁺ (in a 1:1 ratio) fall in the white region demonstrating the possible use of the mixture in white light generation using near‐UV excitation source.     

Microstructure of Nanoscaled La0.6Sr0.4CoO3‐δ Cathodes for Intermediate‐Temperature Solid Oxide Fuel Cells

Nanocrystalline La_1‐xSr_xCoO_3‐δ (LSC) thin films with a nominal Sr‐content of x = 0.4 were deposited on Ce_0.9Gd_0.1O_1.95 electrolyte substrates using a low temperature sol‐gel process. The structural and chemical properties of the LSC thin films were studied after thermal treatment, which included a calcination step and a variable, extended annealing time at 700 °C or 800 °C. Transmission electron microscopy combined with selected‐area electron diffraction, energy‐dispersive X‐ray spectrometry, and scanning transmission electron microscopy tomography was applied for the investigation of grain size, porosity, microstructure, and analysis of the local chemical composition and element distribution on the nanoscale. The area specific resistance (ASR) values of the thin film LSC cathodes, which include the lowest ASR value reported so far (ASR_chem = 0.023 Ωcm² at 600 °C) can be interpreted on the basis of the structural and chemical characterization.     

Electrochemical and Structural Investigation of Calcium Substituted Monoclinic Li3V2(PO4)3 Anode Materials for Li‐Ion Batteries

In this work, the effect of Li⁺ substitution in Li₃V₂(PO₄)₃ with a large divalent ion (Ca²⁺) toward lithium insertion is studied. A series of materials, with formula Li_3?2xCa_xV₂(PO₄)₃/C (x = 0, 0.5, 1, and 1.5) is synthesized and studied in the potential region 3–0.01 V versus Li⁺/Li. Synchrotron diffraction demonstrates that Li₃V₂(PO₄)₃/C has a monoclinic structure (space group P2₁/n), while Ca_1.5V₂(PO₄)₃/C possesses a rhombohedral structure (space group R‐3c). The intermediate compounds, Li₂Ca_0.5V₂(PO₄)₃/C and LiCaV₂(PO₄)₃/C, are composed of two main phases, including monoclinic Li₃V₂(PO₄)₃/C and rhombohedral Ca_1.5V₂(PO₄)₃/C. Cyclic voltammetry reveals five reduction and oxidation peaks on Li₃V₂(PO₄)₃/C and Li₂Ca_0.5V₂(PO₄)₃/C electrodes. In contrast, LiCaV₂(PO₄)₃/C and Ca_1.5V₂(PO₄)₃/C have no obvious oxidation and reduction peaks but a box‐type voltammogram. This feature is the signature for capacitive‐like mechanism, which involves fast electron transfer on the surface of the electrode. Li₃V₂(PO₄)₃/C undergoes two solid‐solution and a short two‐phase reaction during lithiation and delithiation processes, whereas Ca_1.5V₂(PO₄)₃/C only goes through capacitive‐like mechanism. In operando X‐ray absorption spectroscopy confirms that, in both Li₃V₂(PO₄)₃/C and Ca_1.5V₂(PO₄)₃/C, V ions are reduced during the insertion of the first three Li ions. This study demonstrates that the electrochemical characteristic of polyanionic phosphates can be easily tuned by replacing Li⁺ with larger divalent cations.     

Luminescence in Li3Al2(PO4)3:Eu2+

A series of efficient Li₃Al₂(PO₄)₃:Eu²⁺ novel phosphors were synthesized by the facile combustion method. The effects of dopant on the luminescence behavior of Li₃Al₂(PO₄)₃ phosphor were also investigated. The phosphors were characterized by X‐ray diffraction, field emission scanning electron microscope and photoluminescence techniques. The result shows that all samples can be excited efficiently by near‐ultraviolet excitation under 310 nm. The emission was observed for Li₃Al₂(PO₄)₃:Eu²⁺ phosphor at 425 nm, which corresponded to the d → f transition. The concentration quenching of Eu²⁺ was observed in Li₃Al₂(PO₄)₃:Eu²⁺ when the Eu concentration was at 0.5 mol%. The prepared powders exhibited intense blue emission at the 425 nm owing to the Eu²⁺ ion by Hg‐free excitation at 310 nm (i.e., solid‐state lighting excitation). Consequently, the availability of such a phosphor will significantly help in the development of blue‐emitting solid‐state lighting applications. Copyright © 2012 John Wiley & Sons, Ltd.     

Quantum efficiencies,absolute intensities and signal‐to‐blackbody ratios of high‐temperature laser‐induced thermographic phosphors

There are a number of issues related to high‐temperature phosphor thermometry, which include measurement of faster decays, decreasing emission intensity and rising levels of blackbody radiation, that will impose limits on the maximum delectable temperature. This paper provides absolute intensity measurements, quantum efficiencies and signal‐to‐blackbody radiation ratios at peak emission wavelengths, at various temperatures (20–1400°C), for Y₂O₃:Eu, YAG:Tb and YAG:Tm thermographic phosphors under 266 and 355 nm excitation from a Q‐switched Nd:YAG laser. These terms are beneficial in a number of ways for engineers wanting to use a phosphor thermometry solution at high temperatures. They may also provide additional insight to the physical luminescence processes of phosphors at high temperatures. The phosphor signal:blackbody radiation ratio is useful because it combines the effects of blackbody radiation and phosphor emission intensities at various temperatures, providing a valuable quantitative evaluation that can be used as a design aid for phosphor selection. A figure of merit is the temperature when the blackbody radiation equals the phosphor emission (ratio = 1); this is the cross‐over temperature at which the blackbody radiation rapidly starts to overtake and mask out phosphor emissions. To the best of our knowledge no such work exists previously. The results presented show a variation in phosphor intensity with increasing temperature, and although the intensity and quantum efficiencies for Y₂O₃:Eu and YAG:Tb were much greater than YAG:Tm at low temperatures, YAG:Tm was found to be the most efficient phosphor investigated at higher temperatures (>900°C). With a peak emission wavelength of 458 nm, YAG:Tm experienced the lowest proportion of blackbody radiation therefore its advantage at higher temperatures was further amplified and was found to offer an advantage of approximately +350°C and +250°C increased upper temperature capability compared to Y₂O₃:Eu and YAG:Tb phosphors, respectively. Copyright © 2011 John Wiley & Sons, Ltd.