Local structure and structural rigidity of the green phosphor <i>β</i>-SiAlON:Eu<sup>2+</sup>

Brgoch, Jakoah; Gaultois, Michael W.; Balasubramanian, Mahalingam; Page, Katharine; Hong, Byung‐Chul; Seshadri, Ram

doi:10.1063/1.4901104

Cited by 42 publications

(36 citation statements)

References 27 publications

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“…The ordering and rigid structure of β-SiAlON with lower z strongly supports the enhanced thermal stability of β-SiAlON:Eu (529). 46 Meanwhile, The broaden and red-shifted emission of β-SiAlON:Eu with increasing the substitution of Si-N by Al-O can be logically explained by the number of microenviroment around Eu 2+ ions increases, where the number of electronic transitions increases causing overlap, and the new emerging microenvironment of Eu 2+ with disordering structure exhibits a stronger electron-lattice coupling. 29 Si-NMR spectra, (e) 27 Al-NMR spectra and (f) low temperature heat capacity of β-SiAlON:Eu 2+ (529) and β-SiAlON:Eu 2+ (540).…”

Section: +mentioning

confidence: 99%

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

et al. 2017

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Narrow-band green-emitting phosphor β-SiAlON:Eu has been widely used in advanced wide-gamut backlighting devices. However, the origins for unusual sharp lines in photoluminescence emission at room temperature and tunable narrow-bandemission tailored by reducing Al-O in β-SiAlON:Eu are still unclear. Here, the presence of sharp-line fine structure in the emission spectra of β-SiAlON:Eu is mainly due to purely electronic transitions (zero phonon lines) and their vibronic repetitions resulted from the multi-microenvironment around Eu 2+ ions that has been revealed by relative emission intensity of sharp line depends on excitation wavelength and monotonously increasing decay time. The specific features of the Eu 2+ occupying interstitial sites indicate that the effect of crystal field strength can be neglected. Therefore the enhanced rigidity and higher ordering structure of β-SiAlON:Eu with decreasing the substitution of Si-N by Al-O become the main factors in decreasing electron-lattice coupling and reducing inhomogeneous broadening, favouring the blue-shift and narrow of the emission band, the enhanced thermal stability, as well as the charge state of Eu 2+ . Our results provide new insights for explaining the reason for narrow-band-emission in β-SiAlON:Eu, which will deliver an impetus for the exploration of phosphors with narrow band and ordering structure.

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Section: +mentioning

confidence: 99%

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

et al. 2017

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“…12 Θ D measured experimentally using these two methods for a number of phosphor hosts has been shown to agree well with values calculated from DFT-derived parameters. [12][13][14][15] In this work, we explore the structural signatures of several known oxide phosphor hosts, through a careful examination of the average and local structure determined using time-of-flight neutron scattering (including total scattering) and synchrotron powder diffraction methods. The oxide hosts Ba 2 SiO 4 , BaAl 2 O 2 , SrAl 2 O 4 , and Y 2 SiO 5 were studied using these scattering techniques and low-temperature heat capacity measurements.…”

Section: Introductionmentioning

confidence: 99%

Average and Local Structure, Debye Temperature, and Structural Rigidity in Some Oxide Compounds Related to Phosphor Hosts

Denault

Brgoch

Kloß

et al. 2015

ACS Appl. Mater. Interfaces

175

121

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The average and local structure of the oxides Ba2SiO4, BaAl2O4, SrAl2O4, and Y2SiO5 are examined to evaluate crystal rigidity in light of recent studies suggesting that highly connected and rigid structures yield the best phosphor hosts. Simultaneous momentum-space refinements of synchrotron X-ray and neutron scattering yield accurate average crystal structures, with reliable atomic displacement parameters. The Debye temperature ΘD, which has proven to be a useful proxy for structural rigidity, is extracted from the experimental atomic displacement parameters and compared with predictions from density functional theory calculations and experimental low-temperature heat capacity measurements. The role of static disorder on the measured displacement parameters, and the resulting Debye temperatures, are also analyzed using pair distribution function of total neutron scattering, as refined over varying distance ranges of the pair distribution function. The interplay between optimal bonding in the structure, structural rigidity, and correlated motion in these structures is examined, and the different contributions are delineated.

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“…1b. 24 Visualization of the (001) 23,27 et al suggested a highly unusual EuN 9 coordination polyhedron using firstprinciples calculations, and this special coordination environments were highly responsible for the electronic structure characteristic, i.e., a large splitting of > 0.1 eV between the two highest Eu 2+ 4f bands, which ensures the unique narrow-band emission. The Eu 2+ local environments for two representative compositions, z = 0.125 and 0.208, were calculated by Wang, 23 as shown in Figs.…”

Section: β-Sialon:eumentioning

confidence: 99%

Critical Review—Narrow-Band Nitride Phosphors for Wide Color-Gamut White LED Backlighting

Xie

Takeda

et al. 2017

ECS J. Solid State Sci. Technol.

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To achieve a brilliant image with high color saturation in white LED backlighting technology, innovative phosphor materials with narrow-band emission in the green and red spectral region are continuously pursed. Nitride phosphors are so far accepted as the most suitable phosphors for white LED backlights due to their high efficiency and excellent robustness. In this perspective, we will present an overview about the recent developments of state-of-the-art and newly-emerging nitride phosphors with a narrow emission band, and the emphasis would be placed on the relationships between the crystal structure and luminescence properties. Finally, some empirical rules for designing novel narrow-band phosphors for backlighting technologies would be summarized. Nowadays, liquid crystal displays (LCDs) are ubiquitous in our daily lives, and their applications range from smartphones, tablets, computers, to large-screen TVs, and data projectors. As there is much concern on backlight units with larger color gamut, higher brightness, lower power consumption and mercury-free, white light-emitting diodes (LEDs) have been widely applied as backlighting components in modern LCD technologies to replace the traditional cold cathodefluorescence lamps (CCFLs). 1-12Multi-chip white LEDs, which comprise red-, green-and blueemitting chips, exhibit excellent color performance and tuning abilities. However, the efficiencies of red, green, and blue LEDs vary overtime at different rates. In addition, separated driving circuits and complicated feedback-driven systems are required, which leads to a high cost. Moreover, the efficiency of green LEDs, known as "green gap", is much smaller than that of red and blue ones.13-15 By contrast, phosphor-converted (pc) white LED backlights, which combine a single LED chip with phosphor materials, are mostly used due to their high efficiency, cost effectiveness and robustness. To achieve a large color gamut and to faithfully reproduce the natural colors, the emission peak of phosphors should match well with the RGB color filters of LCDs. Phosphors with narrow emission bands would loss less their luminescence after passing through color filters, and also promise high color purity. Therefore, narrow-band phosphors with appropriate emission maximum are required for high efficiency and wide color gamut backlights. 13,15 Quantum dots (QDs) materials have shown great potentials for next-generation displays due to their narrow emission band. [7][8][9][10][11][12] In comparison to traditional CCFL having a color gamut of ∼75% of the National Television Standard Committee (NTSC) standard, the Cdcontaining QDs-integrated white LED backlights promise a large color gamut of > 100% NTSC, but the application has been limited due to the usage restrictions of hazardous Cd compounds. Compared to Cdcontaining rivals, the non-toxic InP/ZnS QDs only yield a color gamut of 87% NTSC due to the quite broader emission band.11 Moreover, it is difficult to maintain the initial optical properties of the QDs during device fabricatio...

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Local structure and structural rigidity of the green phosphor β-SiAlON:Eu²⁺

Cited by 42 publications

References 27 publications

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

Average and Local Structure, Debye Temperature, and Structural Rigidity in Some Oxide Compounds Related to Phosphor Hosts

Critical Review—Narrow-Band Nitride Phosphors for Wide Color-Gamut White LED Backlighting

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Local structure and structural rigidity of the green phosphor β-SiAlON:Eu2+

Cited by 42 publications

References 27 publications

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application

Average and Local Structure, Debye Temperature, and Structural Rigidity in Some Oxide Compounds Related to Phosphor Hosts

Critical Review—Narrow-Band Nitride Phosphors for Wide Color-Gamut White LED Backlighting

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Local structure and structural rigidity of the green phosphor β-SiAlON:Eu²⁺