Broad red-emission of Sr3Y2Ge3O12:Eu2+ garnet phosphors under blue excitation for warm WLED applications

Hussain, Sk. Khaja; Yu, Jae Su

doi:10.1039/c6ra28069b

Cited by 53 publications

(13 citation statements)

References 48 publications

(50 reference statements)

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“…The T 0.5 values for the Eu 3+ and Tb 3+ ions doped CaMoO 4 samples were found to be 146 and 99 °C, respectively. The activation energy (E a ) values for the Eu 3+ and Tb 3+ ions doped CaMoO 4 phosphor powders were obtained from the plots drawn between ln ((I o /I)−1) versus 1/K B T 31 . The plots were then fitted linearly as shown in the inset of Fig.…”

Section: Resultsmentioning

confidence: 99%

Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Bharat

Raju

2017

Sci Rep

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We report the synthesis of spherical-shaped rare-earth (Eu3+ and Tb3+) ions doped CaMoO4 nanoparticles in double solvents (IPA and H2O) with the help of autoclave. The X-ray diffraction patterns well match with the standard values and confirm the crystallization in a tetragonal phase with an I41/a (88) space group. The luminescence spectra exhibit the strong red and green emissions from Eu3+ and Tb3+ ions doped samples, respectively. The X-ray photoelectron spectroscopy results show the oxidation states of all the elements present in the sample. The temperature-dependent luminescence spectra reveal the stability of Eu3+ and Tb3+ ions doped samples. The red- and green-emitting Eu3+ and Tb3+ ions doped CaMoO4 samples were used for detection and enhancement of latent fingerprints which are the common evidences found at crime scenes. The enhanced latent fingerprints obtained on different surfaces have high contrast with low background interference. The minute details of the fingerprint which are useful for individualization are clearly observed with the help of these nanopowders.

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Section: Resultsmentioning

confidence: 99%

Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Bharat

Raju

2017

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“…Currently, phosphor-converted white light-emitting diodes (WLEDs) have been extensively adopted in various solid-state lighting applications due to their superior characteristics such as high efficiency, energy saving, long lifetime, and environmental friendliness compared to the conventional incandescent and uorescent light bulbs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Commonly, the strategy to design commercial WLEDs is the combination of InGaN blue LEDs and Y 3 Al 5 O 12 :Ce 3+ yellow-emitting phosphors. However, the white light obtained from this conguration possesses a low color rendering index (CRI < 80) due to the lack of red component, leading to the restriction of their use in practical applications.…”

Section: Introductionmentioning

confidence: 99%

“…However, the white light obtained from this conguration possesses a low color rendering index (CRI < 80) due to the lack of red component, leading to the restriction of their use in practical applications. [3][4][5] To overcome this issue, new designs for white colors emitted from blends of tricolor (red, green, and blue) phosphors excited by ultraviolet (UV) chips have been developed. [6][7][8][9][10][11][12][13][14] Since these tricolor-phosphors-based WLEDs exhibit excellent CRI (>80) and high conversion efficiency, the exploration of luminescent materials is a big challenge.…”

Section: Introductionmentioning

confidence: 99%

Luminescent properties of Eu³⁺-activated Gd₂ZnTiO₆ double perovskite red-emitting phosphors for white light-emitting diodes and field emission displays

et al. 2018

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“…Figure 1(d) shows the FTIR spectrum of La 2 MoO 6 -La 2 WO 6 :0.24Eu 3+ red-emitting phosphors in the range of 450–4000 cm −1 . The absorption peaks centered at around 3301 and 1671 cm −1 are associated to the O-H symmetric stretching vibration 16,41 . The absorption band located at around 1431 cm −1 is ascribed to the H-O-H blending vibration 42 .…”

Section: Resultsmentioning

confidence: 99%

Eu3+-activated La2MoO6-La2WO6 red-emitting phosphors with ultrabroad excitation band for white light-emitting diodes

2017

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A series of novel Eu3+ -activated La 2 MoO 6 -La 2 WO 6 red-emitting phosphors have been successfully prepared by a citrate-assisted sol-gel process. Both photoluminescence excitation and emission spectra suggest that the resultant products have the strong ultrabroad absorption band ranging from 220 to 450 nm. Under the excitation of 379 nm, the characteristic emissions of Eu 3+ ions corresponding to the 5 D 0 → 7 F J transitions are observed in the doped samples. The optimal doping concentration for Eu 3+ions is found to be 12 mol% and the quenching mechanism is attributed to the dipole-dipole interaction. A theoretical calculation based on the Judd-Ofelt theory is carried out to explore the local structure environment around the Eu 3+ ions. The studied samples exhibit a typical thermal quenching effect with a T 0.5 value of 338 K and the activation energy is determined to be 0.427 eV. A near-ultraviolet (NUV)-based white light-emitting diode (LED) is packaged by integrating a mixture of resultant phosphors, commercial blue-emitting and green-emitting phosphors into an NUV LED chip. The fabricated LED device emits glaring white light with high color rendering index (84.6) and proper correlated color temperature (6492 K). These results demonstrate that the Eu 3+ -activated La 2 MoO 6 -La 2 WO 6 compounds are a promising candidate for indoor lighting as red-emitting phosphors.By virtue of admirable advantages of long working lifetime, energy saving, low cost, high luminous efficiency and environmental compatibility, the phosphor-converted white light-emitting diodes (WLEDs) which are considered as the next-generation illumination sources to supersede the conventional fluorescent lamps have been extensively used in indoor lighting, automobile displays and flashlights [1][2][3][4][5] . Presently, the commercial WLEDs which are made up of a blue-emitting InGaN LED chip and Y 3 Al 5 O 12 :Ce 3+ yellow-emitting phosphors suffer from poor color rending index (CRI ~ 70-80) and high correlated color temperature (CCT ~ 7000 K) as a result of inefficient red emission component [6][7][8] . To circumvent these drawbacks, a new strategy utilizing the near-ultraviolet (NUV) LED chip to pump the hybrid tricolor (blue, green and red) phosphors is performed to emit warm white light [9][10][11] . From the aforementioned combinations, one knows that the eventual behaviors of WLED devices can be significantly affected by the phosphors and they are expected to be efficiently excited by NUV or blue light. In comparison with commercial blue-emitting and green-emitting phosphors, the current red-emitting phosphors, by taking Y 2 O 2 S:Eu 3+ for example, still exhibit some unsatisfied characteristics such as weak absorption in the NUV/blue region, low luminous efficiency and poor stability 12,13 . In order to improve the performance of red-emitting phosphors, the nitride-and germanide-based red-emitting phosphors, such as Ca 2 Si 5 N 8 :Eu 2+ , Sr[LiAl 3 N 4 ]:Eu

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Broad red-emission of Sr₃Y₂Ge₃O₁₂:Eu²⁺ garnet phosphors under blue excitation for warm WLED applications

Abstract: By blending a novel Sr3Y2Ge3O12:Eu2+ red phosphor with a commercial Y3Al5O12:Ce3+ phosphor, a warm WLED was fabricated with a CRI value of 85.81.

Cited by 53 publications

References 48 publications

Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Luminescent properties of Eu³⁺-activated Gd₂ZnTiO₆ double perovskite red-emitting phosphors for white light-emitting diodes and field emission displays

Eu3+-activated La2MoO6-La2WO6 red-emitting phosphors with ultrabroad excitation band for white light-emitting diodes

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Broad red-emission of Sr3Y2Ge3O12:Eu2+ garnet phosphors under blue excitation for warm WLED applications

Abstract: By blending a novel Sr3Y2Ge3O12:Eu2+ red phosphor with a commercial Y3Al5O12:Ce3+ phosphor, a warm WLED was fabricated with a CRI value of 85.81.

Cited by 53 publications

References 48 publications

Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Red and green colors emitting spherical-shaped calcium molybdate nanophosphors for enhanced latent fingerprint detection

Luminescent properties of Eu3+-activated Gd2ZnTiO6 double perovskite red-emitting phosphors for white light-emitting diodes and field emission displays

Eu3+-activated La2MoO6-La2WO6 red-emitting phosphors with ultrabroad excitation band for white light-emitting diodes

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Broad red-emission of Sr₃Y₂Ge₃O₁₂:Eu²⁺ garnet phosphors under blue excitation for warm WLED applications

Luminescent properties of Eu³⁺-activated Gd₂ZnTiO₆ double perovskite red-emitting phosphors for white light-emitting diodes and field emission displays