Europium-Doped Ba7F12Cl2, a Single Component Near-UV Excited Tunable White Phosphor

Hagemann, Hans‐Rudolf; Bill, Hans; Rey, Julien; Kübel, Frank; Calame, Laurent; Lovy, Dominique

doi:10.1021/jp510301p

Cited by 14 publications

(10 citation statements)

References 36 publications

(77 reference statements)

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“…The current study provides indications as to which of the three metal sites of the Ba 7 F 12 Cl 2 structure is preferentially substituted in solid solutions of the type Ba 7-x M x F 12 Cl 2 (M = divalent metal with ionic radius comparable to Ba 2+ ) and hence could help to better understand spectroscopic data of europium-doped Ba 7 F 12 Cl 2 phosphors (Hagemann et al, 2015). The isotypic ordered parent phases Pb 7 F 12 Cl 2 and Ba 7 F 12 Cl 2 were first reported by Aurivillius (1976) and Es-Sakhi et al (1998), respectively.…”

Section: Structure Descriptionmentioning

confidence: 88%

The solid solution Ba_5.78Pb_1.22F₁₂Cl₂

Weil

2016

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The title compound, hexabarium lead(II) decafluoride dichloride, is a solid solution in the system Pb 7 F 12 Cl 2 -Ba 7 F 12 Cl 2 and crystallizes isotypically with the ordered modification of the parent compounds in the space group P6. The coordination polyhedra of the three different metal sites are distorted tricapped trigonal prisms with F 7 Cl 2 coordination sets for two of these sites (Wyckoff positions 3k and 3j, each with site symmetry m..), and the remaining site being exclusively coordinated by fluoride ions (1a, 6..). By sharing faces, a threedimensional structure is accomplished. The three metal sites have remarkably different occupancies by the two types of metal ions. Whereas the site on the 3k position shows only a minor incorporation of Pb 2+ [occupancy ratio Ba:Pb = 0.93 (4):0.07 (4)], the 3j site shows the highest amount of incorporated Pb Structure descriptionThe current study provides indications as to which of the three metal sites of the Ba 7 F 12 Cl 2 structure is preferentially substituted in solid solutions of the type Ba 7-x M x F 12 Cl 2 (M = divalent metal with ionic radius comparable to Ba 2+ ) and hence could help to better understand spectroscopic data of europium-doped Ba 7 F 12 Cl 2 phosphors (Hagemann et al., 2015). The isotypic ordered parent phases Pb 7 F 12 Cl 2 and Ba 7 F 12 Cl 2 were first reported by Aurivillius (1976) and Es-Sakhi et al. (1998), respectively. For a review of crystal-chemical peculiarities in the system BaF 2 /BaCl 2 , including the ordered (space group P6) and disordered modifications (space group P6 3 ) of Ba 7 F 12 Cl 2 , see: Hagemann et al. (2012). The crystal structure of the title compound is shown in Fig. 1 The mixture was placed in a teflon container (capacity 10 ml) which was two-thirds filled with water. The container was closed with a teflon lid and placed in a steel autoclave at 493 K for one week. Colourless crystals with a needle-like form were obtained from the mother liquor by filtration. Unit-cell determination of several selected crystals with subsequent least-squares refinements of the lattice parameters revealed nearly identical unit cells, indicating that the composition of the grown crystals was consistent and very similar to that of the title compound. RefinementThe three M 2+ sites are occupied by both Ba and Pb. For the final model, the three metal sites were constrained to be fully occupied. Each of the sites was refined with common coordinates and displacement parameters for the two types of metals. The highest and lowest remaining electron density peaks are found 2.08 and 0.16 Å , respectively, from the M1 site. The crystal measured was twinned by inversion with an approximate ratio of the twin domains of 1:1 [Flack parameter 0.55 (5)]. Crystal data, data collection and structure refinement details are summarized in Table 2.

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Section: Structure Descriptionmentioning

confidence: 88%

The solid solution Ba_5.78Pb_1.22F₁₂Cl₂

Weil

2016

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“…Several studies have looked at this possibility and single phosphors with multiple luminescent ions, emitting at different wavelengths, have been recently proposed and developed as a solution to this potential problem. These include rear‐earth‐doped phosphors based on several different host crystals, such as phosphates, borates, aluminates, halides and silicates . None of these phosphors is commercially available yet.…”

Section: Spectral Interaction Between Different Phosphor Constituentsmentioning

confidence: 99%

Preparation of balanced trichromatic white phosphors for solid‐state white lighting

et al. 2016

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High quality white light-emitting diodes (LEDs) employ multi-component phosphor mixtures to generate light of a high color rendering index (CRI). The number of distinct components in a typical phosphor mix usually ranges from two to four. Here we describe a systematic experimental technique for starting with phosphors of known chromatic properties and arriving at their respective proportions for creating a blended phosphor to produce light of the desired chromaticity. This method is applicable to both LED pumped and laser diode (LD) pumped white light sources. In this approach, the radiometric power in the down-converted luminescence of each phosphor is determined and that information is used to estimate the CIE chromaticity coordinate of light generated from the mixed phosphor. A suitable method for mixing multi-component phosphors is also described. This paper also examines the effect of light scattering particles in phosphors and their use for altering the spectral characteristics of LD- and LED-generated light. This is the only approach available for making high efficiency phosphor-converted single-color LEDs that emit light of wide spectral width.

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“…This approach allows the superposition of multiple emission contributions depending on the location of the luminescent center in different environments. [7,8] However, the emission and the occupancy of the dopant in each crystallographic site are difficult to predict/control, making any discovery of a single-phase white phosphor challenging. Another strategy consists in combining in a single host different dopants emitting in different spectral regions [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Tuning the oxidation states of dopants in Li2SrSiO4:Eu,Ce and control of the photoemission color

Yuan

Génois

Glais

et al. 2020

Journal of Solid State Chemistry

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A color-tunable phosphor Li 2 SrSiO 4 :Eu 2+ ,Eu 3+ ,Ce 3+ was synthesized by solid state reaction in reducing atmosphere followed by a controlled heating treatment of the compound in air at different temperatures. Due to the different temperatures of oxidation of Eu 2+ into Eu 3+ and Ce 3+ into Ce 4+ , Eu 2+ / Eu 3+ / Ce 3+ / Ce 4+ ions can coexist in the Li 2 SrSiO 4 host and enable a tunable coloration of the "blue-yellow-red" photoemission to obtain white luminescence.

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Europium-Doped Ba₇F₁₂Cl₂, a Single Component Near-UV Excited Tunable White Phosphor

Cited by 14 publications

References 36 publications

The solid solution Ba_5.78Pb_1.22F₁₂Cl₂

The solid solution Ba_5.78Pb_1.22F₁₂Cl₂

Preparation of balanced trichromatic white phosphors for solid‐state white lighting

Tuning the oxidation states of dopants in Li2SrSiO4:Eu,Ce and control of the photoemission color

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Europium-Doped Ba7F12Cl2, a Single Component Near-UV Excited Tunable White Phosphor

Cited by 14 publications

References 36 publications

The solid solution Ba5.78Pb1.22F12Cl2

The solid solution Ba5.78Pb1.22F12Cl2

Preparation of balanced trichromatic white phosphors for solid‐state white lighting

Tuning the oxidation states of dopants in Li2SrSiO4:Eu,Ce and control of the photoemission color

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Product

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Europium-Doped Ba₇F₁₂Cl₂, a Single Component Near-UV Excited Tunable White Phosphor

The solid solution Ba_5.78Pb_1.22F₁₂Cl₂

The solid solution Ba_5.78Pb_1.22F₁₂Cl₂