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US-20260125595-A1 - LUMINOPHORE, METHOD FOR PRODUCING A LUMINOPHORE AND RADIATION-EMITTING COMPONENT

US20260125595A1US 20260125595 A1US20260125595 A1US 20260125595A1US-20260125595-A1

Abstract

A luminophore is disclosed which includes a host material that includes an oxide, along with an activator element containing a rare earth element in two different valence states—the second being higher than the first. Also disclosed are a method for producing the luminophore and a radiation-emitting component incorporating the luminophore.

Inventors

  • Philipp Pust
  • Barbara Huckenbeck

Assignees

  • AMS-OSRAM INTERNATIONAL GMBH

Dates

Publication Date
20260507
Application Date
20231004
Priority Date
20221012

Claims (19)

  1. 1 - 16 . (canceled)
  2. 17 . A radiation emitting component comprising: a semiconductor chip that emits electromagnetic radiation of a first wavelength range during operation, a conversion element comprising a luminophore, which converts electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range which is partially different from the first wavelength range, wherein the luminophore comprises: a host material containing an oxide, an activator element comprising a rare earth element having a first valency, and wherein the rare earth element has a second valency that is greater than the first valency, and wherein the luminophore has the general formula (Y, Lu, Gd, Tb) 3 (Al 1-x ,Ga x ) 5 O 12 :Ce y 3+ Ce 1-y 4+ wherein 0≤x≤1 and 0<y<1
  3. 18 . The radiation-emitting component according to claim 17 , wherein the conversion element additionally comprises a base luminophore, wherein the base luminophore differs from the luminophore only in that it is free of the rare earth element having the second valency.
  4. 19 . The radiation-emitting component according to claim 17 , wherein the radiation-emitting component is a light-emitting diode or a laser.
  5. 20 . The radiation-emitting component according to claim 17 , wherein the conversion element comprises a mixture of the luminophore (Y, Lu, Gd, Tb) 3 (Al 1-x ,Ga x ) 5 O 12 :Ce y 3+ Ce 1-y 4+ wherein 0≤x≤1 and 0<y<1 and the base luminophore (Y, Lu, Gd, Tb) 3 (Al 1x ,Ga x ) 5 O 12 :Ce 3+ wherein 0≤x≤1.
  6. 21 . The radiation-emitting component according to claim 18 , wherein a ratio of luminophore to base luminophore in the conversion element is selected from 100:0, 80:20, and 60:40.
  7. 22 . The radiation-emitting component according to claim 17 , wherein the luminophore is free of divalent co-dopands.
  8. 23 . The radiation-emitting component according to claim 17 , wherein the luminophore has an absorption range with an absorption maximum, wherein the absorption maximum has a position which is substantially identical to a position of an absorption maximum of a base luminophore, and wherein the base luminophore differs from the luminophore only in that it is free of the rare earth element having the second valency.
  9. 24 . The radiation-emitting component according to claim 23 , wherein the absorption range of the luminophore is at least in the UV to blue wavelength range of the electromagnetic spectrum.
  10. 25 . The radiation-emitting component according to claim 17 , wherein the luminophore has a quantum efficiency that is reduced compared to a quantum efficiency of a base luminophore, and wherein the base luminophore differs from the luminophore only in that it is free of the rare earth element having the second valency.
  11. 26 . The radiation-emitting component according to claim 17 , wherein an electromagnetic radiation emitted from the luminophore has a dominant wavelength which is substantially identical to a dominant wavelength of a base luminophore, and wherein the base luminophore differs from the luminophore only in that it is free of the rare earth element having the second valency.
  12. 27 . The radiation-emitting component according to claim 17 , wherein an electromagnetic radiation emitted by the luminophore has a half-width which is substantially identical to a half-width of a base luminophore, and wherein the base luminophore differs from the luminophore only in that it is free of the rare earth element having the second valency.
  13. 28 . The radiation-emitting component according to claim 17 , wherein the luminophore has a brightness which decreases with increasing proportion of the rare earth element having the second valency in the luminophore.
  14. 29 . A luminophore, comprising: a host material containing an oxide, an activator element comprising a rare earth element having a first valency, and wherein the rare earth element has a second valency, the second valency being greater than the first valency, and wherein the luminophore has the general formula (Y, Lu, Gd, Tb) 3 (Al 1-x ,Ga x ) 5 O 12 :Ce y 3+ Ce 1-y 4+ wherein 0≤x≤1 and 0<y<1.
  15. 30 . A method for producing a luminophore comprising: providing a base luminophore comprising: a host material containing an oxide, and an activator element comprising a rare earth element with a first valency, oxidizing of the base luminophore to a luminophore comprising the host material containing an oxide, the activator element comprising a rare earth element having a first valency, and wherein the rare earth element has a second valency, the second valency being greater than the first valency, wherein the luminophore has the general formula: (Y, Lu, Gd, Tb) 3 (Al 1-x ,Ga x ) 5 O 12 :Ce y 3+ Ce 1-y 4+ where 0≤x≤1 and 0<y<1.
  16. 31 . The method according to claim 30 , wherein the oxidation is carried out at a temperature from the range including 350° C. to including 1400° C.
  17. 32 . The method according to claim 30 , wherein the oxidation is carried out in air or oxygen, and/or wherein the oxidation is carried out for a period of from including one hour up to and including five hours.
  18. 33 . The method according to claim 30 , wherein the base luminophore (Y, Lu, Gd, Tb) 3 (Al 1-x ,Ga x ) 5 O 12 :Ce 3+ wherein 0≤x≤1 is provided and is oxidized to the luminophore (Y, Lu, Gd, Tb):(Al 1-x ,Ga x ) 5 O 12 :Ce y 3+ Ce 1-y 4+ wherein 0≤x≤1 and 0<y<1.
  19. 34 . The method according to claim 30 , wherein no divalent co-dopands are used.

Description

RELATED APPLICATIONS This application is a US National Stage application, filed under 35 U.S.C. § 371, of International Application PCT/EP2023/077426, filed on Oct. 4, 2023, and claims priority to German patent application 10 2022 126 567.6, filed on Oct. 12, 2022, the entirety of the above listed applications is incorporated herein by reference. FIELD A luminophore, a method for producing a luminophore and a radiation-emitting component are disclosed. SUMMARY At least one embodiment relates to a luminophore with improved properties. At least one further embodiment relates to a method for producing a luminophore with improved properties. At least one further embodiment relates to a radiation-emitting component with improved properties. The various embodiments can use A luminophore is disclosed. According to at least one embodiment, the luminophore comprises a host material containing an oxide, an activator element comprising a rare earth element having a first valency, and the rare earth element having a second valency, wherein the second valency is greater than the first valency. The luminophore described here therefore contains the same rare earth element with two different valencies, the first valency and the second valency. The term “luminophore” is understood here and in the following to mean a wavelength conversion substance or conversion substance for short, i.e. a material that is set up to absorb and emit electromagnetic radiation. In particular, the luminophore absorbs electromagnetic radiation that has a different wavelength maximum than the electromagnetic radiation emitted by the luminophore. For example, the luminophore absorbs radiation with a wavelength maximum at shorter wavelengths than the emission maximum and thus emits radiation with an emission maximum shifted towards red. Pure scattering or pure absorption are not understood as wavelength-converting in the present case. Here and in the following, “host material” means a crystalline material, for example a ceramic material, into which the rare earth element is incorporated. The luminophore is therefore a ceramic material, for example. In particular, the host material forms a host lattice, which is made up of a generally periodically repeating three-dimensional unit cell. In other words, the unit cell is the smallest recurring unit of the crystalline host lattice. The elements contained in the host material, the rare earth element with the first valency and the rare earth element with the second valency, each occupy fixed positions in the unit cell, so-called point positions. The term “valency” in relation to a specific element refers to how many elements with a single opposite charge are required in a chemical compound in order to achieve a charge balance. The term “valency” therefore includes the charge number of the element. Here and in the following, first valency and second valency are to be understood as two different valencies. For example, the first valency is valency 3 and the second valency is valency 4. The rare earth element can thus be present in the luminophore in trivalent and tetravalent form. In particular, the trivalent rare earth element has a triple positive charge and the tetravalent rare earth element has a quadruple positive charge. The rare earth element with the first valency has the function of an activator element in the luminophore. The activator element changes the electronic structure of the host material in such a way that electromagnetic radiation of a first wavelength range can be absorbed by the luminophore. This so-called primary radiation can excite an electronic transition in the luminophore, which can return to the ground state by emitting electromagnetic radiation of a second wavelength range, also known as secondary radiation. The activator element, which is introduced into the host material, is thus responsible for the wavelength-converting properties of the luminophore. In particular, the secondary radiation has wavelengths in the visible spectral range. Part of the rare earth element is present in oxidized form, i.e. with a higher, second valency. In particular, the rare earth element with the second valency does not have the function of an activator element or does not lead to a conversion of the primary radiation into a secondary radiation, which is in the visible spectral range of electromagnetic radiation. In order to differentiate between the rare earth element with first valency and with second valency, only the rare earth element with first valency is referred to here and in the following as the activator element. Rare earth elements include the chemical elements of the 3rd subgroup of the periodic table as well as the lanthanides. Rare earth elements are generally selected from the group formed by scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. The inventors