Red-emitting Phosphor Material Research Articles

Luminescence studies of high color purity red-emitting [formula omitted] phosphor prepared by microwave-assisted synthesis technique

A set of red-emitting phosphor materials (Ca1−xAl4O7:Eux3+, x = 0, 0.01, 0.03, 0.05, 0.07, 0.09, 0.11, 0.13) were synthesized through microwave-assisted combustion synthesis for the first time. The crystal structures and phase purity of Eu3+ ions-activated calcium dialuminate (CaAl4O7) phosphor were investigated by XRD study and Rietveld refinement analysis were performed. The prepared phosphors exhibit monoclinic crystal structure having C2/c space group. From the radius difference percentage calculation, the occupancy of Eu3+ ions in Ca2+ sites was confirmed which is in better harmony with the refinement result. Morphological analysis was investigated through SEM study. Structural characteristics and the presence of the functional groups were analysed though FTIR study. The optical band gap (Eg) was determined to be 5.46 eV by studying the UV–VIS reflectance spectra. PL measurements were carried out for the prepared material to study the luminescent behaviour. The presence of charge transfer band was observed in the excitation spectra. It is found that the prepared phosphor materials exhibits emission rich in red at 611 nm with fixed excitation wavelength at 393 nm. The concentration quenching and energy transfer kinetics were analysed by employing Blasse and Dexter’s formula that attributed the non-radiative energy transfer to the dipole-dipole (d-d) interactions. Local site symmetry was analysed to study the symmetry of the environment in the neighbourhood of Eu3+ ions in the host matrix. To analyse the colorimetric performance of the phosphor materials, the correlated color temperature (CCT), color purity were calculated by using the CIE chromaticity co-ordinates (CIE 1931). The calculated CCT value shows the appearance of the emitted color of the phosphor in the warmer region. CaAl4O7:Eu3+ phosphor manifests high color purity which was found to be 97.39 %. The PL decay time measurement were performed for Ca1−xAl4O7:Eux3+ (x = 0.07) phosphor to obtain the decay lifetime. The estimated decay time (1.44 ms) indicates that the prepared phosphor material has a good potency to be utilized as a red-emitting phosphor for wLED, display technology and other applications.

Effect of Eu3+ doping on structural and optical properties of zirconium titanate

The Europium activated (1–9 mol %) Zirconium Titanate nanoparticles (NPs) have been synthesized by the green solution combustion method using Aloe Vera gel extract as a reducing agent, followed by the calcination at 720 °C for 3hrs. All the synthesized samples crystallize in a pure orthorhombic crystal structure with the space group of Pbcn. The surface and bulk morphology were analyzed. The crystallite size increases, whereas the direct energy band gap was found to decrease with an increase in dopant concentration. Further, the effect of dopant concentration on the photoluminescence properties was studied. The presence of Eu3+ ion in the trivalent state in the host lattice was confirmed by its characteristic emission at 610 nm due to 5D0→7F2 (λex = 464 nm). The CIE coordinates were found in the red region of the CIE 1931 diagram. The CCT coordinates lie in the range 6288–7125 K. The Judd-Ofelt parameters and derived quantities were analyzed. This theory confirms the high symmetry of Eu3+ ions in the host lattice. These findings imply that ZTO:Eu3+ can be employed as a nanopowder material in a red-emitting phosphor material.

Eu3+ as a spectroscopic probe to understand local site-luminescence correlation in novel Y2TiO5:Eu3+ phosphor

Red emitting phosphor materials play a very important role in improving the color rendering index and lighting efficiency of phosphor-converted white light-emitting diodes (pc-WLEDs). However, the research pertaining to design and development of the same has somehow saturated with real lack of novel compositions and functionalities. In this work, a sincere effort has been vested in designing relatively new compositions Y2TiO5:x%Eu3+(x = 1–10) using simple solid-state reactions for efficient, narrow and pure red emission. Europium is distributed at both Y(1) and Y(2) site with higher excited state lifetime. Under the optimal mid and near ultraviolet light excitation, Y2TiO5:5%Eu3+shows a strong red emission at 608 nm with a high color purity of 99.96% and a moderate internal quantum efficiency of 13%. Impressively, this red-emitting phosphor exhibits a concentration quenching at 5.0 mol%, internal QY of ∼34%, lower non-radiative channels and higher branching ratio. Trend in Judd-Ofelt parameter suggested that there is monotonic increase in degree of distortion and as the concentration increases Eu-O bond becomes highly polarizable. This work and the obtained results suggested that Y2TiO5:Eu3+ phosphor has great potential to serve as red emitting phosphor for pc-WLEDs, opening a new perspective for developing new titanate-based luminescent materials.

Novel high-saturated red-emitting phosphor Sr9(Mg0.5Mn0.5)K(PO4)7: Eu2+ with great quantum efficiency enhancement by La3+ codoping for white LED application

In this work, a novel whitlockite-structure red-emitting phosphor host, Sr9(Mg0.5Mn0.5)K(PO4)7, is designed and successfully synthesized via a solid-state reaction. Upon X-ray diffractometer Rietveld refinement, it is revealed that this compound possesses compact Eu2+-Mn2+ distance (3.6809 Å) and large intra-Mn2+ distance (8.9905 Å), which is beneficial to the high-efficient Eu2+-Mn2+ energy transfer. By Eu2+ sensitization, our new phosphor exhibits a high-saturated and bright red Mn2+ emission at 620 nm with high color purity of 97.9%. Great emission enhancement up to 245 times than host is achieved by La3+ heterovalent substitution, which can be ascribed to the La3+-induced further structural confinement effect. Moreover, the quantum efficiency is boosted by twofold. The as-fabricated white phosphor-converted LEDs device shows bright warm white light with correlated color temperature (CCT) of 3,487 K, color-rendering index (CRI) of 92.4, and luminous efficacy of 31.59 lm/W. This work proves the feasibility of chemical unit co-substitution strategy in emission engineering of Mn2+-based phosphors, which can stimulate further studies on the red-emitting phosphor materials.

The local symmetry of trivalent europium ion activated Li4Ca2B8O16 red-emitting phosphors with high color purity and excellent thermal stability

Exploring for red-emitting phosphor materials with supper property plays a key role in the development of white light-emitting diodes (WLEDs). Simultaneously, the crystal structure has a crucial effect on its luminescence properties. In this work, we synthesized a type of new red-emitting Li4Ca2B8O16: Eu3+ phosphor via the solid-state reaction. The phase purity, crystal structure, surface morphology, decay behavior, thermal stability, the correspondence between local symmetry and luminescence properties were investigated in detail. Under the optimal 393 nm excitation, Li4Ca2B8O16: 0.33Eu3+ shows a strong red emission located at 612 nm ascribed to the 5D0→7F2 transition of Eu3+. The calculated Judd-Ofelt parameters (Ω2 and Ω4) have clarified that Eu3+ has lower symmetry without an inversion center, resulting in the high value of R/O (the emission intensity ratio of 5D0→7F2 to 5D0→7F1) of 7.95 at x = 0.33 mol. The Li4Ca2B8O16: 0.33Eu3+ phosphor exhibits a high color purity of 94.99% with the chromaticity coordinates of (0.6547, 0.3449), perfect internal quantum efficiency (99.75%) and excellent thermal stability at high temperature (90.91% at 150 °C). The results indicate that this new Li4Ca2B8O16: Eu3+ phosphor can be used as the potential red component for pc-WLEDs.

Red emitting non-rare earth doped LiMgBO3 phosphor for light emitting diodes

Cost-effective non-rare earth doped phosphor materials, particularly Mn4+ activated nitrides and fluorides, are emerging as prospective alternatives to rare earth doped red-emitting phosphor materials for light emitting diodes. Yet, it is challenging to prepare such cost-effective and high purity red-emitting non-rare earth doped phosphors because of their broad emission profiles and difficulties in the synthesis of nitrides and fluorides. In order to overcome the challenges faced in developing cost-effective and efficient materials for lighting solutions, we report a new red-emitting Mn4+ doped LiMgBO3 phosphor synthesized by solution combustion and solid-state routes. The phosphors had broad excitation bands in the UV (200–400 nm) and blue (400–560 nm) regions of the spectrum. Under both UV/visible excitation, the phosphors emit at 664 and 669 nm for the materials synthesized through solid-state and combustion route respectively and the corresponding full width at half maxima were 94 nm and 40 nm. The photoluminescence (PL) intensity of the phosphor synthesized by combustion method, was found to be six times higher than that synthesized through the solid-state route. The effect of crystal field environment on the PL properties, evaluated from crystal field strength and the Racah parameters (B and C), showed that Mn4+ ions were present in a strong octahedral field for both synthesis methods. X-ray photoelectron spectroscopy confirmed the existence of all the elements on the surface of the phosphors. Temperature dependent PL studies and the photometric properties such as color purity, International Commission on Illumination chromaticity coordinates of the phosphors were also evaluated.

Exploring Na0.1Sr9.8Eu0.1(PO4)6F2 both as a potential phosphor material and host for radioactive waste immobilization

In this work, we have reported synthesis and characterization of Na0.1Sr9.8Eu0.1(PO4)6F2, which has potential application for immobilization of radioactive waste and also as red-emitting phosphor material. From PL spectra and lifetime study it was concluded that most of the Eu3+ ions (which are surrogate of radioactive Am3+ ions in the radioactive waste) are preferentially occupying M2A site which has a fluoride ion linkage compare to the M1A site without any such linkage. This was further supported by the XRD study. The compound is also found to be red emitting phosphor material for its application in LEDs with color purity of 86.13%. In order to investigate the radiation stability of the matrix considering its application in nuclear waste immobilization, the compound was exposed to different doses of gamma radiation and subsequent emission profiles are then recorded. We have observed that there was an initial increase in the intensity of the PL spectra due to the creation of the electron-hole pair. However, at very high doses such as 1000 kGy, the created defects provide non-radiative pathways to the excited state of Eu3+ ion which leads to decay in intensity. TL study showed the presence of different shallow and deep trap state for electron and hole generated due to irradiation. EPR study characterized various irradiation-induced defect states which play a prominent role in the emission characteristics.

Reddish emission of europium doped zinc oxide nanophosphor prepared through precipitation route using sodium borohydride

The main objective of this research work is to develop a desired reddish emission of europium (Eu)-doped zinc oxide (ZnO) nanophosphor, prepared through precipitation route using sodium borohydride (NaBH4), as a precipitating agent and also study its structure, powder morphology as well as photoluminescence characteristics, especially asymmetric ratio or colour purity. X-ray diffraction of the calcined (600 °C) Eu (3 mol%)-doped ZnO powders confirmed the presence of pure phase ZnO and also suggested that the europium ions are incorporated in the lattice sites of Zn ions due to the increase in lattice volume as well as peak (101) shifting towards the lower angle. FESEM and TEM analysis confirmed that the particles of Eu-doped ZnO are elongated or elliptical rod-like, having length in the range of 200 nm – 400 nm as well as polyhedral in shape. Photoluminescence behaviour indicate an intense broad transition of 5D0→7F2 (compared to transition of 5D0→7F1) corresponds to red emission, when the sample was excited at 464 nm. The ratio of integrated maximum emission intensities between 5D0 → 7F2 and 5D0 → 7F1 transitions was found to be ∼5.9. The value of asymmetric ratio or colour purity and the position of CIE coordinates suggested that the Eu-doped ZnO nanopowders may be used as red emitting phosphor material.

Doping induced effect on optical and band structure properties of Sr2Si5N8 based phosphors: DFT approach

Nitrido silicates are emerged as highly efficient luminescent materials (phosphors) that found considerable industrial application as white light emitting diodes (LEDs) have been studied with respect to band structure and related electronic structure parameters. They have tunable optical properties, as the band gap is of indispensable because it determines both the electrical and optical features of the material, which can be varied by the material composition (by doping technique). It is found also that the nitride (alumo) silicates “Sr2Si5N8: Eu2+” have wide industrial application as highly efficient red-emitting phosphor materials in pc-LEDs. In this report we apply density functional theory (DFT) within the GGA+U approach to study the structural, electronic and optical properties of Eu2+ and Ce3+ doped Sr2Si5N8. The total energy has been optimized as a function of the unit cell volume. Electronic structure including, the electronic density of state (DOS), the band structure and the linear optical susceptibility are calculated for the relaxed structure applying the optimized lattice constant. The calculated optical dispersion of dielectric susceptibility are closely related to the corresponding electronic structure and our results are in very good agreement with experimental data.

(Invited) Red Fluoride Phosphors: A Story of Reliability

Ever since the introduction of the high-brightness blue LED in 1994 [1], research on photoluminescent materials has gained tremendous interest. The combined emission from a blue emitting LED chip and a yellow emitting phosphor yields white light. The first white LEDs (wLEDs) were based on an (In,Ga)N LED chip and the efficient, chemically stable yellow phosphor Y3Al5O12:Ce3+. Despite the high luminous efficacy of the radiation (LER) attainable with this single phosphor wLED, the performance in terms of color rendering is low due to a lack of red emission. Improvement of the color rendering index (CRI) requires an additional emitter in the red spectral region. Therefore, tremendous effort has been spent on the development of red emitting phosphor materials. Red sulfide phosphors such as (Ca,Sr)S:Eu2+ [2] were first investigated. However, the poor chemical stability and strong thermal quenching associated with sulfides led research to new phosphor classes. Due to their high chemical stability and high quantum efficiency, Eu2+ nitride phosphors [3] such as CaAlSiN3:Eu2+ are currently considered as the most suited candidate for wLED applications. Nevertheless, even the Eu2+ doped nitrides possess serious drawbacks. Apart from their higher production cost, they often suffer from broad excitation- and emission bands. Excitation bands extending beyond 500 nm cause reabsorption issues when used in a phosphor blend together with green or yellow phosphors. On the other hand, broad emission bands partially reaching above 650 nm are inefficient as the human eye sensitivity becomes negligible in this spectral region. Several red fluoride phosphors show a saturated red emission band below 650 nm based on the photoluminescence of Mn4+ in an octahedral fluorine coordination. In addition to their optimal optical performance, the low-cost production by means of wet chemical synthesis is an additional benefit. However, trace impurities in the form of impurity phases and secondary Mn valences often occur after synthesis. The present study reveals a strong correlation between purity after synthesis and stability of K2SiF6:Mn4+, a benchmark red fluoride phosphor [4-6]. Recently a two-step precipitation method has gained interest to improve the Mn valence related issue. K2MnF6, is first synthesized as a precursor material, incorporating Mn4+ in a [MnF6]2- coordination complex. In a second step, these complexes are incorporated in a fluoride host by dropwise addition of K2MnF6/KF in 40% HF and SiO2 in 40% HF. Although the chemical yield is higher compared to other chemical routes, such as wet chemical etching, and some improvements in stabilizing the Mn4+ valence state can be expected, careful examination of the purity proves necessary. Combined feedback from in- and ex-situ X-ray diffraction, diffuse reflection spectroscopy, X-ray absorption near edge spectroscopy, thermal gravimetric and differential thermal analysis revealed the presence of impurities after synthesis of K2SiF6:Mn4+. On the one hand, hydrated secondary crystalline phases, such as KMnF4•H2O, K2MnF5•H2O and similar hydrated structures, are easily formed during synthesis. As a result, parasitic absorption due to Mn3+ occurs which limits the attainable quantum efficiency of the as-synthesized impure phosphor. On the other hand, impurities such as KHF2 severely increase the hygroscopic behavior of the phosphor after synthesis. KHF2 is easily hydrolyzed, leading to hydrated KF, an impurity hardly detectable by XRD at room temperature. As a result of water absorption in the impure phosphor, a further reduction of Mn4+ to Mn3+ is observed when the phosphor is placed in high humidity. Nevertheless, detection, identification and elimination of these impurities lead to efficient and high purity K2SiF6:Mn4+, showing good chemical and thermal stability. To further enhance stability, thin protective Al2O3, TiO2 or SiO2 shells were coated using thermally assisted, plasma enhanced or ozone enhanced Atomic Layer Deposition (ALD) and subsequently evaluated. Nakamura, S., M. Senoh, and T. Mukai, High‐power InGaN/GaN double‐heterostructure violet light emitting diodes. Applied Physics Letters, 1993. 62(19): p. 2390-2392. Hu, Y., et al., Preparation and luminescent properties of (Ca1-x,Srx)S:Eu2+ red-emitting phosphor for white LED. Journal of Luminescence, 2005. 111(3): p. 139-145. Li, S., et al., Critical Review—Narrow-Band Nitride Phosphors for Wide Color-Gamut White LED Backlighting. ECS Journal of Solid State Science and Technology, 2017. 7(1): p. R3064-R3078. Sijbom, H.F., et al., K2SiF6:Mn4+ as a red phosphor for displays and warm-white LEDs: a review of properties and perspectives. Optical Materials Express, 2017. 7(9): p. 3332-3365. Murphy, J.E., et al., PFS, K2SiF6:Mn4+: the Red-line Emitting LED Phosphor behind GE's TriGain Technology™ Platform. SID Symposium Digest of Technical Papers, 2015. 46(1): p. 927-930. Paulusz, A.G., Efficient Mn(IV) Emission in Fluorine Coordination. Journal of The Electrochemical Society, 1973. 120(7): p. 942-947.

Novel molybdenum based pyrochlore type red phosphors, NaGd1−xSnMoO7: xEu3+ under near UV and blue excitation

Novel molybdenum based pyrochlore type red emitting phosphor materials: NaGd1−xSnMoO7: xEu3+ were prepared by the conventional solid state route. The developed phosphors were characterized for their structure as well as luminescent properties. The NaGd1−xSnMoO7: xEu3+ phosphors show strong red emission at 615nm corresponding to the forced electric dipole transition 5D0→7F2 under near-UV and blue excitation. Further these phosphors exhibit high color purity characterized by sharp red emissions (fwhm ~6nm) with high asymmetric ratio. The color coordinates of all the samples under 393nm excitation were calculated and found to be (0.65, 0.35) which are comparable to the standard color coordinates for red (0.67, 0.33). Thus the synthesized phosphors could be suitable red candidates in phosphor converted white light emitting diode applications.

Narrow-Band Red Emission in the Nitridolithoaluminate Sr4[LiAl11N14]:Eu2+

The new narrow-band red-emitting phosphor material Sr4[LiAl11N14]:Eu2+ was synthesized by solid-state reaction using a tungsten crucible with a cover plate in a tube furnace. When excited with blue light (460 nm), it exhibits red fluorescence with an emission maximum at 670 nm and a full width at half-maximum of 1880 cm–1 (∼85 nm). The crystal structure was solved and refined from single-crystal X-ray diffraction data. This new compound from the group of the nitridolithoaluminates crystallizes in the orthorhombic space group Pnnm (No. 58) with the following unit-cell parameters: a = 10.4291(7) A, b = 10.4309(7) A, and c = 3.2349(2) A. Sr4[LiAl11N14]:Eu2+ shows a pronounced tetragonal pseudo-symmetry. It consists of a framework of disordered (Al/Li)N4 and AlN4 tetrahedra that are connected to each other by common corners and edges. Along the [001] direction, the tetrahedral network creates empty four-membered-ring channels as well as five-membered-ring channels, in which the Sr2+ cations are located.

Narrow-band red-emitting Sr[LiAl₃N₄]:Eu²⁺ as a next-generation LED-phosphor material.

To facilitate the next generation of high-power white-light-emitting diodes (white LEDs), the discovery of more efficient red-emitting phosphor materials is essential. In this regard, the hardly explored compound class of nitridoaluminates affords a new material with superior luminescence properties. Doped with Eu(2+), Sr[LiAl3N4] emerged as a new high-performance narrow-band red-emitting phosphor material, which can efficiently be excited by GaN-based blue LEDs. Owing to the highly efficient red emission at λ(max) ~ 650 nm with a full-width at half-maximum of ~1,180 cm(-1) (~50 nm) that shows only very low thermal quenching (>95% relative to the quantum efficiency at 200 °C), a prototype phosphor-converted LED (pc-LED), employing Sr[LiAl3N4]:Eu(2+) as the red-emitting component, already shows an increase of 14% in luminous efficacy compared with a commercially available high colour rendering index (CRI) LED, together with an excellent colour rendition (R(a)8 = 91, R9 = 57). Therefore, we predict great potential for industrial applications in high-power white pc-LEDs.

Ca[LiAl3N4]:Eu2+—A Narrow-Band Red-Emitting Nitridolithoaluminate

Ca[LiAl3N4]:Eu2+ is an intriguing new narrow-band red-emitting phosphor material with potential for application in high-power phosphor-converted light-emitting diodes (pc-LEDs). With excitation by blue InGaN-based LEDs, the compound exhibits an emission maximum at 668 nm with a full width at half maximum of only 1333 cm–1 (∼60 nm). Ca[LiAl3N4]:Eu2+ was synthesized from Ca, LiAlH4, LiN3, AlF3, and EuF3 in weld-shut Ta ampules, and the structure was solved and refined on the basis of single-crystal X-ray diffraction data. After isotypical crystallization with Na[Li3SiO4], the compound forms a highly condensed framework of AlN4 and LiN4 tetrahedra [I41/a (no. 88), Z = 16, a = 11.1600(16) A, and c = 12.865(3) A] and can thus by classified as a nitridolithoaluminate. Both types of polyhedra are connected to each other by common edges and corners, yielding a high degree of condensation, κ = 1. The Ca site is positioned in the center of vierer ring channels along [001] and coordinated in a cuboidal manner by eig...

Time resolved microscopic cathodoluminescence spectroscopy for phosphor research

In impurity doped inorganic luminescent materials, there is often a close relation between the structural and optical properties. When a phosphor shows a distribution of structural properties (such as local variations in composition, dopant concentration, crystalline phase or particle size), the luminescence properties can show a similar distribution. When evaluating the synthesized phosphors at the macroscopic scale only, these properties are averaged out, which can lead to a broadened emission spectrum or a luminescence decay curve consisting of several exponentials.This paper discusses cathodoluminescence detection inside a scanning electron microscope (SEM-CL) for the study of local emission characteristics in phosphors. In this type of instrument, imaging, local element identification as well as cathodoluminescent spectral mapping can be performed. It is shown that with the aid of a beam blanker, local decay time analysis and spectrally resolved decay time mapping can be performed. By correlating simultaneously obtained structural, compositional and luminescence properties, a profound understanding of a phosphor's behavior can be obtained. This is illustrated on Ca2SiS4:Eu, a red-emitting phosphor material of current interest for white light emitting diode (LED) wavelength conversion.

Photoluminescence characteristics of new stannate pyrochlore based red phosphors: CaLaSnNbO7: Eu3+

New stannate pyrochlore based red emitting phosphor materials: CaLa1−x SnNbO7: xEu3+ were prepared by the conventional solid state route and characterized by Powder X-ray diffractometer, scanning electron microscope and fluorescence measurements. Optimization studies by way of varying the calcination temperatures show that CaLaSnNbO7: Eu3+ prepared at 1,400 °C displayed the maximum luminescence characteristics. The dominant emission peak of CaLaSnNbO7: xEu3+ phosphor is 5D0 → 7F2 forced hypersensitive electric dipole transition which indicates the deviation of pyrochlore A-site from inversion symmetry. The present quaternary pyrochlore phosphors show strong red luminescence (~612 nm) under near UV (394 nm) and blue light (465 nm) excitations.

Novel powellite-based red-emitting phosphors: CaLa 1−xNbMoO 8: xEu 3+ for white light emitting diodes

We report the photoluminescence properties of a novel powellite-based red-emitting phosphor material: CaLa 1− x NbMoO 8: xEu 3+ (0.01, 0.03, 0.05, 0.1) for the first time. The photoluminescence investigations indicated that CaLa 1− x NbMoO 8: xEu 3+ emits strong red light at 615 nm originating from 5 D 0→ 7 F 2 (electric dipole transition) under excitation either into the 5 L 0 state with 394 nm or the 5 D 2 state with 464 nm, that correspond to the two popular emission lines from near-UV and blue LED chips, respectively. When compared with emission intensity from a CaMoO 4:Eu 3+, the emission from CaLaNbMoO 8:Eu 3+ showed greater intensity values under the same excitation wavelength (394 nm). The enhanced red emission is attributed to the enhanced f– f absorption of Eu 3+. These materials could be promising red phosphors for use in generating white light in phosphor-converted white light emitting diodes (WLEDs).

Synthesis of Gd 2Ti 2O 7:Eu 3+, V 4+ phosphors by sol–gel process and its luminescent properties

A red-emitting phosphor material, Gd 2Ti 2O 7:Eu 3+, V 4+, by added vanadium ions is synthesized using the sol–gel method. Phosphor characterization by high-resolution transmission electron microscopy shows that the phosphor possesses a good crystalline structure, while scanning electron microscopy reveals a uniform phosphor particle size in the range of 230–270 nm. X-ray photon electron spectrum analysis demonstrates that the V 4+ ion promotes an electron dipole transition of Gd 2Ti 2O 7:Eu 3+ phosphors, causing a new red-emitting phenomenon, and CIE value shifts to x=0.63, y=0.34 (a purer red region) from x=0.57, y=0.33 (CIE of Gd 2Ti 2O 7:Eu 3+). The optimal composition of the novel red-emitting phosphor is about 26% of V 4+ ions while the material is calcinated at 800 °C. The results of electroluminescent property of the material by field emission experiment by CNT-contained cathode agreed well with that of photoluminescent analysis.