WO2018185116A2

WO2018185116A2 - Uranyl-sensitized europium luminophores

Info

Publication number: WO2018185116A2
Application number: PCT/EP2018/058515
Authority: WO
Inventors: Ralf Petry; Ingo Koehler; Aleksander ZYCH; Katharina SIEVERT; Thomas Juestel; Florian BAUR
Original assignee: Merck Patent Gmbh
Priority date: 2017-04-07
Filing date: 2018-04-04
Publication date: 2018-10-11
Also published as: WO2018185116A3

Abstract

Disclosed are novel uranyl-sensitized europium luminophores which are particularly suitable for use as radiation converters in semiconductor light sources that emit blue light or UV-A radiation.

Description

Uranyl-sensitized europium phosphors

FIELD OF THE INVENTION

The invention is in the field of phosphors and relates to new uranyl compounds, a process for their preparation, their use and components containing the substances.

STATE OF THE ART

For the realization of warm white light sources based on blue or UV-A emitting (ln, Ga) N LEDs red-emitting phosphors are required in addition to the yellow or green-emitting garnets or ortho-silicates, the strong enough absorb at the corresponding wavelength of the primary radiation (370 - 480 nm) and

Show photoluminescence (PL) with high quantum efficiency. At the same time, the stability of these phosphors must be similar to that of the garnets or ortho-silicates, so that it does not come in the course of the life of the solid-state light source to an undesirable color point shift.

For this purpose, a number of phosphors have been proposed or developed in the past 20 years, the latter

Meet requirements. The phosphors used so far, namely (Ca, Sr) S: Eu, (Ca, Sr) AISiN ₃ : Eu, O and (Ca, Sr, Ba) 2Si ₅ N ₈ : Eu are all based on the activator Eu ²⁺ , the itself through a broad

Absorption spectrum as well as characterized by a broad emission band. The major drawback of these Eu ²⁺ activated materials is their relatively high sensitivity to photodegradation because the divalent Eu ²⁺ tends to photoionize, especially in relatively low band gap host materials. Another disadvantage is the quite high

Half-width of the Eu ²⁺ emission band, which manifests itself in a moderate lumen equivalent (<200 Im / W), when the color point in the deep red

Spectral range is. This observation is especially true for the phosphors (Ca, Sr) S: Eu and (Ca, Sr) AISiN ₃ : Eu, O.

As an alternative, as proposed in the international patent application WO 2012 128837 A2 (GENERAL ELECTRIC), the narrow-band red-emitting phosphor K2SiF6: Mn ^{4+ was} developed, which shows no emission in the deep red spectral range and thus significantly higher Efficiency (lumen equivalent> 300 Im / W) has. However, due to the quantum-mechanically forbidden 3d ³ -3d ³ transition, the absorption in the blue spectral range is significantly lower than for comparably concentrated Eu ²⁺ -based phosphors. Therefore, they are relatively high

Amounts required to produce warm white light. Furthermore, Mn ⁴⁺ in fluoridic host materials tends to undergo a redox reaction with the F ^~ anions leading to the formation of elemental fluorine and Mn ³⁺ , with degradation of the phosphor.

For this reason, it would be desirable to develop a red-emitting phosphor that does not have these disadvantages. Eu ³⁺ and Mn ⁴⁺ or Sm ³⁺ doped phosphors are particularly suitable for this purpose, since they are red in the red spectral range between approximately 610 and 660 nm

Have line emission.

In the international patent application WO 2015 139806 A1 (MERCK) it is proposed to use Tb ³⁺ for the sensitization. The absorption strength in the blue and near-UV spectral range is indeed significantly improved, but not in a comparable and required with Eu ²⁺ level.

Despite enormous research activities in this area, it has not yet been possible to provide a Eu ³⁺ doped phosphor with sufficiently high absorption strength for semiconductor LEDs available. The object of the present invention has therefore been to overcome the described disadvantages of the prior art and to provide phosphors with which it is possible to realize a warm white LED with high color rendering (CRI> 90) and simultaneously high lumen equivalent. It would be high

Lumen equivalents (-200 - 250 Im / W) and absorption strengths in the

Spectral range of 300 to 500 nm also particularly desirable. DESCRIPTION OF THE INVENTION

A first subject of the invention relates to uranyl-sensitized europium phosphors of the empirical formula (I)

[A] _a [U0 ₂ ] b [B] _c [0] d [OH] _e * f H ₂ O (I) with the following meanings:

and the dimers corresponding to the empirical formula.

For the sake of good order, it should be noted that the above meanings for the corresponding element characters according to

Periodic table stand. It should also be noted that the formula (I) is a molecular formula and not a structural formula. In this sense, the term "dimers" should also be understood:

What is meant are crystal structures which in total contain twice the amount of a substance of the formula (I).

Surprisingly, it was found that the

New Eu ³⁺ -doped uranyl compounds according to the invention are particularly suitable as radiation converters in blue light or UV light emitting semiconductor light sources and thus solve the object stated at the outset in an excellent manner.

The new substances are characterized in particular by a high absorption strength in the aforementioned radiation ranges.

While uranyl compounds generally emit green, the phosphors of the present invention surprisingly follow in sequence of an unexpectedly efficient energy transfer between the [UO2] ²⁺ cation and the Eu ^3+, an emission with a red color point in the red.

In this connection, US Pat. No. 3,586,634 A (GENERAL TELEPHONE) from 1971, which likewise discloses Eu-doped uranium phosphors, but which are present in the hexavalent state as (UO3) units, should be mentioned. In the article titled XU ET AL

"Incorporation of radioactive metals and trace metals into phosphates" anhydrous "autunite" (MATERIALS RES SOC SYMP PROC (2002), VOL DATE 2003, 757, p. 447-454) are doped with europium

Uranylphosphate described which have the formula EuU2O ₄ (PO ₄ ) 2.

The luminophores thus obtained have a high lumen equivalent (-200 to 250 lm / W) and a luminescent material activated for Eu ³⁺ very high absorption strength in the spectral range of 300 to 500 nm. In

Combined with a blue-emitting semiconductor light source and a green-emitting phosphor, such as Eu ²⁺ -activated SiAlON or ortho-silicate, or green or yellow-emitting Ce ³⁺ -activated garnets, it is possible to realize phosphor-converted LEDs (pcLED) Color temperature in warm white range (<= 3000 K) is. By

By lowering the Eu ³⁺ concentration x, the color point of the

Move emission from the red to the green-yellow area.

As a result, for the first time now also phosphor converted

Semiconductor light sources, which, unlike conventional warm white pcLEDs, require only a single phosphor as the converter. A homogeneous mixture and an exact mixing ratio of the phosphors in the converter layer is not required in this case. This generally leads to a lower reject rate in production and a higher color point stability during operation.

[0015] FLUORES

A first preferred embodiment of the present invention comprises various subtypes of the formula (I), as they are hereafter again e:

not only because of their special performance, but also because of their high chemical resistance. This is especially true for compounds of type (1.1).

Further preferred are the following concrete substances which form a further subgroup according to the invention:

In sum, preference is given to those bulbs containing europium further at least one rare earth metal, which is selected from the group formed by yttrium, lanthanum, samarium and

Neodymium.

The preferred uranyl compounds are also phosphates or arsenates. In the general formula (I), in further preferred embodiments, the indices (b) and (c) independently of one another for 1, 2, 3 or 4 and the indices (d) and (e) independently for 0, 1, 2, 3 or 4 stand.

It has also been found that it is advantageous for the properties of the phosphors if they are free of water of crystallization or in any case not more than 7 crystal water units.

In the context of this application is referred to as UV light such light whose emission maximum is between 100 and 399 nm, as violet light denotes such light whose emission maximum is between 400 and 430 nm, as blue light denotes such light whose emission maximum between 431 and 480 nm, as cyan light, whose emission maximum is between 481 and 510 nm, as green light, and its emission maximum between

51 1 and 565 nm is, as yellow light such, its emission maximum between 566 and 575 nm, such as orange light, whose

Emission maximum is between 576 and 600 nm, and as red light, whose emission maximum is between 601 and 750 nm.

In a further embodiment, the compounds of the invention can be coated. Suitable for this purpose are all the coating methods known to the person skilled in the art according to the prior art and used for phosphors. Suitable materials for the coating are, in particular, metal oxides and nitrides, in particular earth metal oxides, such as Al 2 O 3, and earth metal nitrides, such as AlN, and also SiO 2. The coating can be carried out, for example, by fluidized bed processes or wet-chemical. Suitable coating methods are known, for example, from JP 04-304290, WO 91/10715, WO

99/27033, US 2007/0298250, WO 2009/065480 and WO 2010/075908. On the one hand, the aim of the coating can be a higher stability of the phosphors, for example against air or moisture. The goal can also be an improved coupling and decoupling of light by a suitable choice of the surface of the coating and the

Refractive indices of the coating material. [0022] MANUFACTURING PROCESS

Another object of the invention relates to a process for the preparation of phosphors of the formula (I) consisting of or

comprising the following steps:

(a) providing an aqueous solution containing

(a1) a water-soluble uranyl salt

(a2) a water-soluble europium salt and optionally

(a3) one, two or more water-soluble salts of rare earth metals, alkali metals and / or alkaline earth metals;

(b) adding the solution of step (a) with a water-soluble acid or a water-soluble oxide of a metal or non-metal selected from the group consisting of sulfur, selenium, tellurium, chromium, molybdenum, tungsten, carbon, phosphorus, arsenic, Vanadium or mixtures thereof, in an amount sufficient to the solubility of the reaction product

exceed and precipitate this;

(c) separating the precipitate from the aqueous phase as well (d) drying and optionally calcining the thus obtained

Solid.

Particularly suitable as water-soluble salts are the acetates of the substances mentioned. The components (a1) and (a2 + a3) may preferably be in a molar ratio of about 2: 1 to about 1: 3,

preferably about 1: 1 to about 1: 1, 5 are used.

The solution are then added to the water-soluble acids or oxides of said metals or non-metal. Phosphoric acid or arsenic oxides are preferably suitable here, it being possible for the molar ratio of these substances, based on the uranyl salts, to be from about 1: 1 to about 1: 5 and preferably from about 1: 2 to about 1: 4;

particularly preferred is a ratio of 2: 3.

These proportions are sufficient to the salts formed from the reaction of the two components, ie the

Phosphors according to the invention to precipitate as usually yellow-colored precipitate. If appropriate, it is beneficial to adjust the pH by adding alkali hydroxide in the direction of the alkaline range and, for example, to a value of about 5. The reaction preferably takes place with stirring at temperatures in the range of 20 to 50 ° C and usually leads after 2 to 5 days to a complete precipitate of the phosphor. This is usually filtered off, washed several times and then, for example, in a

Autoclave dried at 180 ° C (10 bar) for one to two days. INDUSTRIAL APPLICABILITY

Another object of the present invention relates to the use of the compounds of the invention as phosphors or conversion phosphors, in particular as a radiation converter in blue light or UV-A radiation emitting semiconductor sources, which is why the compounds are therefore also referred to as generic as phosphors.

[0028] EMISSION CONVERTING MATERIALS

The present invention also relates to a

emission converting material comprising a compound of the invention. The emission-converting material may be derived from the In this case, it would be equivalent to the above-defined term "conversion luminescent substance." It may also be preferred that the emission-converting material according to the invention comprises, in addition to the compound according to the invention, further compounds

Conversion phosphors contains. In this case, the emission-converting material according to the invention preferably contains a mixture of at least two conversion phosphors, at least one of which is a compound according to the invention. It is particularly preferred that the at least two conversion phosphors are phosphors which emit light with mutually complementary wavelengths.

If the compounds of the invention are used in small amounts, they already give good LED qualities. The LED quality is doing with usual parameters, such as the Color

Rendering Index (CRI), the Correlated Color Temperature (CCT),

Lumen equivalents or absolute lumens or the color point in CIE x and y coordinates described:

The Color Rendering Index (CRI) is a familiar to the expert, unitless photometric size, which the

Color fidelity of an artificial light source compares to that of sunlight or filament light sources (the latter two have a CRI of 100).

The Correlated Color Temperature (CCT) is a familiar with the expert, photometric quantity with the unit Kelvin. The higher the numerical value, the higher the blue component of the light and the colder the white light of an artificial radiation source appears to the viewer. The CCT follows the concept of the black light emitter, whose

Color temperature describes the so-called Planckian curve in the CIE diagram.

The lumen equivalent is a photometric quantity known to those skilled in the art with the unit Im / W, which describes how large the photometric luminous flux in lumens of a light source at a certain radiometric radiation power with the unit watts. The higher the lumen equivalent, the more efficient a light source is.

The lumen is a photometrical photometric quantity which is familiar to the person skilled in the art and which measures the luminous flux of a light source which is a measure of the total visible radiation emitted by a radiation source Radiation is, describes. The larger the luminous flux, the brighter the light source appears to the observer.

CIE x and CIE y stand for the coordinates in the familiar CIE standard color chart (here normal observer 1931), with which the color of a light source is described.

All the variables listed above can be calculated from the emission spectra of the light source using methods known to those skilled in the art.

The excitability of the phosphors of the invention extends over a wide range, ranging from about 250 to about 550 nm, preferably from about 300 to about 460 nm, and more preferably from about 400 to about 460 nm. Usually, the maximum of the excitation curve is between 325 and 375 nm. [0038] LIGHT SOURCES

Another object of the present invention is a light source containing at least one primary light source and at least one compound of the invention. The maximum emission of the primary light source is usually in the range of about 250 to about 550 nm, and preferably in the range of about 300 to about 460 nm. Most preferably, a range between 400 and 460 nm, wherein the primary radiation partially or completely by the inventive Phosphor is converted into longer-wave radiation.

In a preferred embodiment of the light source according to the invention, the primary light source is a luminescent indium-aluminum-gallium-nitride, in particular of the formula IniGajAlkN, where 0 <i, 0 <j, 0 <k, and i + j + k = 1.

The person skilled in possible forms of such light sources are known. These may be light-emitting LED chips of different construction.

In a further preferred embodiment of the

The light source according to the invention is a luminescent arrangement based on ZnO, TCO (transparent condueting oxide), ZnSe or SiC or else an arrangement based on an organic light-emitting layer (OLED). In a further preferred embodiment of the

The light source according to the invention is a source which exhibits electroluminescence and / or photoluminescence. Furthermore, the primary light source can also be a plasma or discharge source.

Corresponding light sources according to the invention are also referred to as light-emitting diodes or LEDs.

[0045] FLUID MIXTURES

The phosphors according to the invention can be used individually or as

Mixture with suitable phosphors, which are familiar to the expert used. Corresponding phosphors which are suitable in principle for mixtures are, for example:

The compound according to the invention shows particular advantages in the mixture with other phosphors of other fluorescence dyes or when used in LEDs together with such phosphors. The compounds according to the invention are preferred together with green and / or yellow and / or orange-emitting phosphors

used. It has been shown that the optimization of illumination parameters for white LEDs succeeds particularly well when combining the compounds according to the invention with green and / or yellow and / or orange-emitting phosphors.

Corresponding green, yellow and orange emitting phosphors are known to the person skilled in the art or the person skilled in the art can select from the list given above. In a further preferred

Embodiment of the invention, it is preferred that inventive

Use compound as the only phosphor. The compound of the invention shows by the broad emission spectrum with a high proportion of red even when used as a single fluorescent very good results.

In yet another embodiment of the invention, it is preferred, when the phosphors are arranged on the primary light source, that the red emitting phosphor is substantially illuminated by the light of the primary light source, while the green emitting phosphor is substantially illuminated by the light is that has already passed through the red emitting phosphor or was scattered by this. This can be realized by mounting the red emitting phosphor between the primary light source and the green emitting phosphor.

The phosphors according to the invention or

Fluorescent combinations may be present as bulk material, powder material, thick or thin layer material or self-supporting material, preferably in the form of a film. Furthermore, it may be in a potting material be embedded. The phosphors according to the invention or

Here, phosphor combinations can be dispersed either in a resin (eg epoxy or silicone resin) as Vergussmatehal, or at appropriate size ratios directly on the primary light source

or may be remotely located therefrom, depending on the application (the latter arrangement also includes "remote phosphor technology.") The advantages of "remote phosphor technology" are well known to those skilled in the art, e.g. in the following publication: JAPANESE J. OF APPL. PHYS. VOL. 44, no. 21 (2005), L649-L651.

In a further embodiment, it is preferred if the optical coupling between the phosphor and the primary light source is realized by a light-conducting arrangement. This makes it possible that the primary light source is installed at a central location and this by means of light-conducting devices, such as photoconductive

Fibers, is optically coupled to the phosphor. In this way, the lighting requirements adapted lights can only be realized consisting of one or more different phosphors, which can be arranged to form a luminescent screen, and a light guide, which is coupled to the primary light source realize. In this way, it is possible to place a strong primary light source at a convenient location for the electrical installation and to install without further electrical wiring, but only by laying fiber optics at any location lights of phosphors, which are coupled to the light guide.

[0053] LIGHTING UNITS

Further subject of the invention are a lighting unit, in particular for the backlight of display devices, characterized in that it contains at least one light source according to the invention, and a display device, in particular liquid crystal display device (LC display), with a backlight, characterized in that it comprises at least one lighting unit according to the invention contains.

The particle diameter Dv50 of the invention

For use in LEDs, phosphors are usually between 50 nm and 30 μm, preferably between 1 μm and 20 μm. The Dv50 value is the Median of the particle size distribution and it refers to the maximum particle diameter, below which 50% of the sample volume is present. The Dv50 value divides the volume-based particle size distribution curve into two equal (area) parts, ie 50% of the particles are smaller and 50% of the particles are larger than the Dv50 value. the

Persons skilled in the art are well aware of suitable methods for determining the volume-based particle size distribution curve as well as the Dv50 value.

For use in LEDs, the phosphors can also in any external forms, such as spherical particles, platelets and structured

Materials and ceramics are transferred. These forms are summarized under the term "shaped body" according to the invention.

Preferably, the shaped body is a

A further subject matter of the present invention is thus a shaped body containing the phosphors according to the invention

Expert familiar from numerous publications.

All variants of the invention described here can be combined with each other, provided that the respective embodiments are not mutually exclusive. In particular, it is based on the teaching of this document in the context of routine optimization

obvious process, just to combine different variants described here, to a particular particular preferred

Embodiment to get. The following examples are intended to illustrate the

The present invention in particular clarifies and shows the result of such exemplary combinations of those described

Variants of the invention. However, they are by no means limiting

but rather to stimulate generalization. All compounds or components used in the formulations are either known and commercially available or can be synthesized by known methods. The in the examples

given temperatures are always in ° C. It goes without saying that both in the description and in the

Examples are the amounts of ingredients used in the

Always add up to a total of 100%. Percentages are always to be seen in the given context. The invention is explained in more detail below by embodiments and the figures 1 to 10 without being limited thereto. The illustrations show the following:

The phase formation of the samples was carried out by means of

X-rayed iffraktomet e checked. For this purpose, the X-ray iffractometer Miniflex II of the Rigaku company with Bragg-Brentano geometry was used. The radiation source was an X-ray tube with Cu-Ka radiation (λ =

0.15418 nm). The tube was operated with a current of 15 mA and a voltage of 30 kV. It was measured in an angle range of 10 to 80 ° with 10 ^o -min ^{~ 1} .

The emission spectra were measured with a fluorescence spectrometer from Edinburgh Instruments Ltd., equipped with a mirror optics for powder samples, at an excitation wavelength of 450 nm added. The excitation source used was a 450 W Xe lamp. For temperature-dependent measurement of the emission was the spectrometer with a cryostat from Oxford Instruments

equipped (MicrostatN2). Nitrogen was used as the coolant.

EXAMPLES

EXAMPLE 1

Eu (UO ₂ ) 3 (PO ₄ ) ₂ O (OH) -6H ₂ O

0.4372 g (1, 000 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g

(3,000 mmol) (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml of H ₂ O at 40 ° C with stirring. 0.2306 g (2.000 mmol) of 85% H ₃ PO are added in 40 ml H ₂ O and both solutions are combined with stirring. It forms a yellow precipitate. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling Η ₂ Ο. The resulting powder is dispersed in H 2 O, transferred to an autoclave and heated at 180 ° C. for 48 h

(corresponding to a pressure of 10 bar) held. The product is dried in air.

EXAMPLE 2

(Yo _> 5Euo _> 5) (U0 ₂ ) 3 (PO ₄ ) ₂ 0 (OH) -6H ₂ 0

0.2186 g (0.5000 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O, 0.1871 g

(0.5000 mmol) Y (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol)

(UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml of H ₂ O at 40 ° C with stirring. 0.2306 g (2.000 mmol) of 85% H ₃ PO are added in 40 ml H ₂ O and both solutions are combined with stirring. It forms a yellow precipitate. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling H ₂ O. The resulting powder is dissolved in H ₂ O

dispersed, transferred to an autoclave and 48 h at 180 ° C.

(corresponding to a pressure of 10 bar) held. The product is dried in air. EXAMPLE 3

0.4372 g (1, 000 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g

(3,000 mmol) (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml of H ₂ O at 40 ° C with stirring. 0.2298 g (2.000 mmol) As ₂ O ₅ are dissolved in 40 ml H ₂ O. Both solutions are combined with stirring. It forms a yellow precipitate. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling H ₂ O. The resulting powder is dissolved in H ₂ O

dispersed, transferred to an autoclave and 48 h at 180 ° C.

(corresponding to a pressure of 10 bar) held. The product is dried in air. 0067 EXAMPLE 4

o _{; 5 0>} 5 ₂ 3 _{4 2 2}

0.2186 g (0.5000 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O, 0.1871 g

(0.5000 mmol) Y (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol)

(UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml of H ₂ O at 40 ° C with stirring. 0.2298 g (2.000 mmol) As ₂ O ₅ are dissolved in 40 ml H ₂ O. Both solutions are combined with stirring. It forms a yellow

Rainfall. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling H ₂ O. The resulting powder is dissolved in H ₂ O

dispersed, transferred to an autoclave and 48 h at 180 ° C.

(corresponding to a pressure of 10 bar) held. The product is dried in air. 0069 EXAMPLE 5

, _>;

0.2099 g (0.4800 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O, 0.1871 g

(0.5000 mmol) Y (CH ₃ COO) ₃ -6H ₂ O, 0.0087 g (0.020 mmol)

Sm (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol) of (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml H ₂ O at 40 ° C. with stirring. 0.2306 g (2.000 mmol) of 85% H ₃ PO ₄ are added in 40 ml H ₂ O and both solutions are combined with stirring. It forms a yellow precipitate. The pH is with

1 M NaOH adjusted to 5. The dispersion is stirred at 40 ° C. for 36 h. Of the Precipitate is filtered off and washed several times in boiling H2O. The resulting powder is dispersed in H 2 O, transferred to an autoclave and kept at 180 ° C (corresponding to a pressure of 10 bar) for 48 h. The product is dried in air.

EXAMPLE 6

0.2099 g (0.4800 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O, 0.1871 g

(0.5000 mmol) Y (CH ₃ COO) ₃ -6H ₂ O, 0.0086 g (0.020 mmol)

Sm (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol) of (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml H ₂ O at 40 ° C. with stirring. 0.2306 g (2.000 mmol) of 85% H ₃ PO ₄ are added to 40 ml of H ₂ O and both solutions are combined with stirring. It forms a yellow precipitate. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling H2O. The resulting powder is dispersed in H 2 O, transferred to an autoclave and kept at 180 ° C (corresponding to a pressure of 10 bar) for 48 h. The product is dried in air. EXAMPLE 7

0.3817 g of La (CH ₃ COO) ₃ -6H ₂ O (0.900 mmol), 0.0437 g (0.100 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol ) (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml of H ₂ O at 40 ° C. with stirring. 0.2306 g (2.000 mmol) of 85% H ₃ PO ₄ are placed in 40 ml of H ₂ O and both solutions are added

Stirring combined. It forms a yellow precipitate. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling H2O. The resulting powder is dispersed in H 2 O, transferred to an autoclave and kept at 180 ° C (corresponding to a pressure of 10 bar) for 48 h. The product is dried in air.

EXAMPLE 8

0.3367 g of Y (CH ₃ COO) ₃ -6H ₂ O (0.900 mmol), 0.0437 g (0.100 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol ) (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml H ₂ O at 40 ° C with stirring. 0.2306 g (2.000 mmol) of 85% H3PO ₄ are added in 40 ml H2O and the two solutions combined with stirring. It forms a yellow precipitate. The pH is adjusted to 5 with 1 M NaOH. The dispersion is stirred at 40 ° C. for 36 h. The precipitate is filtered off and washed several times in boiling H2O. The resulting powder is dispersed in H 2 O, transferred to an autoclave and kept at 180 ° C (corresponding to a pressure of 10 bar) for 48 h. The product is dried in air. EXAMPLE 9

0.1871 g of Y (CH ₃ COO) ₃ -6H ₂ O (0.500 mmol), 0.2185 g (0.500 mmol) of Eu (CH ₃ COO) ₃ -6H ₂ O and 1.2724 g (3.000 mmol ) (UO ₂ ) (CH ₃ COO) ₂ -2H ₂ O are dissolved in 80 ml of H ₂ O at 40 ° C. with stirring. 0.2306 g (2.000 mmol) of 85% H ₃ PO ₄ are placed in 40 ml of H ₂ O and both solutions are added

Claims

Uranyl-sensitized europium phosphors of the empirical formula (I)

[A] _a [UO ₂ ] b [B] c [O] d [OH] e ^* f H ₂ O (I) having the following meanings:

and the dimers corresponding to the empirical formula.

Phosphors according to claim 1, characterized in that they are selected from the subgroup formed by:

Phosphors according to claim 1 or 2, characterized in that they are selected from the subgroup formed by

Phosphors according to one or more of claims 1 to 3, characterized in that they further comprise at least one

Containing rare earth metal selected from the group formed by yttrium, lanthanum, samarium and neodymium.

Phosphors according to one or more of claims 1 to 4, characterized in that they are uranyl phosphates or Uranylarsenate.

Phosphors according to one or more of claims 1 to 5, characterized in that the indices (b) and (c) are independently 1, 2, 3 or 4.

Phosphors according to one or more of claims 1 to 6, characterized in that the indices (d) and (e) are independently 0, 1, 2, 3 or 4.

8. phosphors according to one or more of claims 1 to 7, characterized in that they are free of water of crystallization or have not more than 7 crystal water units.

Process for the preparation of phosphors of the formula (I) consisting of or comprising the following steps:

(a) providing an aqueous solution containing

(a1) a water-soluble uranyl salt

(a2) a water-soluble europium salt and optionally

(a3) one, two or more water-soluble salts of

Rare earth metals, alkali metals and / or alkaline earth metals;

(b) adding the solution of step (a) with a water-soluble acid or a water-soluble oxide of a metal or non-metal selected from the group consisting of sulfur, selenium, tellurium, chromium, molybdenum, tungsten, carbon, phosphorus, arsenic, Vanadium or mixtures thereof in an amount sufficient to exceed and precipitate the solubility product of the reaction product;

(c) separating the precipitate from the aqueous phase as well

(d) drying and optionally calcining the thus obtained

Solid.

A method according to claim 9, characterized in that one uses phosphoric acid or an arsenic oxide.

A method according to claim 9 or 10, characterized in that one uses the water-soluble acids or water-soluble oxides, based on the uranyl salts, in a molar ratio of 1: 1 to 1: 5.

Use of the compounds according to one or more of claims 1 to 8 as a phosphor or radiation converter in blue light or UV-A radiation emitting semiconductor light sources.

13. An emission converting material comprising a phosphor according to one or more of claims 1 to 8 and

optionally at least one further conversion luminescent substance. 14. A light source, comprising a primary light source and at least one phosphor according to one or more of claims 1 to 8 or an emission-converting material according to claim 13.

15. Lighting unit, comprising at least one light source according to claim 14.