Search

EP-4388059-B1 - PHOSPHOR COMPOSITIONS AND SHORT WAVELENGTH INFRARED EMITTING PCLEDS EMITTING IN THE 1600-2200 NM WAVELENGTH RANGE

EP4388059B1EP 4388059 B1EP4388059 B1EP 4388059B1EP-4388059-B1

Inventors

  • SCHMIDT, PETER JOSEF
  • DIEDERICH, THOMAS

Dates

Publication Date
20260506
Application Date
20220621

Claims (15)

  1. A wavelength converting structure comprising an SWIR phosphor having emission wavelengths in the range of 1600 - 2200 nm, the SWIR phosphor comprising a structurally disordered garnet material, a sensitizer ion, and at least one rare earth emitter ion, wherein the SWIR phosphor comprises (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e ]{Ga 3-c Al c }O 12 with RE = La, Y, Yb, Nd, Er, Ce and 0 ≤ u ≤ 2, 0 < v ≤ 1, 0 < x ≤ 1, 0 < y ≤ 0.5 , 0 ≤ z ≤ 0.05 , 0 < a ≤ 1, 0 < b ≤ 0.3 ,0 ≤ c ≤ 3, 0 < d ≤ 1.8, 0 ≤ e ≤1.8.
  2. The wavelength converting structure of claim 1, wherein the structurally disordered garnet material comprises a cubic garnet host lattice with 8-fold coordinated Gd atoms, 6-fold coordinated Ga atoms, and 4-fold coordinated Ga atoms.
  3. The wavelength converting structure of claim 1, wherein the structurally disordered garnet material comprises one or more atoms selected from the group Sc, Lu, Ga and Al that can occupy more than one lattice site and at a concentration greater than 1 atom%.
  4. The wavelength converting structure of claim 1, wherein the rare earth emitter ion comprises at least one of Tm, Ho, La, Y, Yb, Nd, Er, and Ce.
  5. The wavelength converting structure of claim 1, wherein the rare earth emitter ion consists of Tm and Ho, or wherein the rare earth emitter ion consists of Tm.
  6. The wavelength converting structure of claim 1, wherein the SWIR phosphor comprises at least one of Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 , Gd 2.59 Tm 0.24 Ho 0.02 Sc 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 , Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 , and Gd 2.67 Ho 0.01 Tm 0.17 Sc 1.8 Lu 0.3 Ga 2 AlCr 0.05 O 12 .
  7. The wavelength converting structure of claim 1, further comprising an additional IR phosphor having emission in the wavelength range of 1100-1700 nm.
  8. The wavelength converting structure of claim 7, wherein the additional IR phosphor comprises one or more of Ni 2+ , Ni 2+ and Cr 3+ doped spinel, perovskite, and garnet type IR phosphor emitting in the 1000-1700 nm range.
  9. A luminescent material that emits lighting having emissions wavelengths in the range of 1600 - 2200 nm, the luminescent material comprising a structurally disordered garnet material doped with at least one sensitizer ion and at least one rare earth emitter ion, wherein the luminescent material comprises (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e ]{Ga 3-c Al c }O 12 with RE = La, Y, Yb, Nd, Er, Ce and 0 ≤ u ≤ 2, 0 < v ≤ 1, 0 < x ≤ 1, 0 < y ≤ 0.5, 0 ≤ z ≤ 0.05, 0 < a ≤ 1, 0 < b ≤ 0.3, 0 ≤ c ≤ 3, 0 < d ≤ 1.8, 0 ≤ e ≤1.8.
  10. The luminescent material of claim 9, wherein the structurally disordered garnet material comprises a cubic garnet host lattice with 8-fold coordinated Gd atoms, 6-fold coordinated Ga atoms, and 4-fold coordinated Ga atoms.
  11. The luminescent material of claim 9, wherein the structurally disordered garnet material comprises one or more atoms selected from the group Sc, Lu, Ga and Al that can occupy more than one lattice site and at a concentration greater than 1 atom%.
  12. The luminescent material of claim 9, wherein the rare earth emitter ion comprises at least one of Tm, Ho, La, Y, Yb, Nd, Er, and Ce.
  13. The luminescent material of claim 9, wherein the rare earth emitter ion consists of Tm and Ho, or wherein the rare earth emitter ion consists of Tm.
  14. The luminescent material of claim 9, wherein the SWIR phosphor comprises at least one of Gd 2.367 Ho 0.01 Tm 0.152 Sc 1.6 Lu 0.27 Ga 1.8 Al 1.78 Cr 0.04 O 12 , Gd 2.59 Tm 0.24 Ho 0.02 SC 0.75 Lu 0.3 Ga 2 Al 2 Cr 0.1 O 12 , Gd 2 Ho 0.013 Tm 0.2 Sc 0.67 Lu 0.24 Ga 1.6 Al 3.2 Cr 0.08 O 12 , and Gd 2.67 Ho 0.01 Tm 0.17 Sc 1.8 Lu 0.3 Ga 2 AlCr 0.05 O 12 .
  15. An IR emitting device comprising: - a wavelength converting structure, the wavelength converting structure comprising an SWIR phosphor having emission over a wavelength range of 1600-2200 nm with a continuous emission spectrum over a spectral width of at least 500 nm, wherein the SWIR phosphor comprises (Gd 3-u-v-x-y-z Lu x Tm y Ho z Sc v RE u )[Sc 2-a-b-d-e Lu a Cr b Ga d Al e ]{Ga 3-c Al c }O 12 with RE = La, Y, Yb, Nd, Er, Ce and 0 ≤ u ≤ 2, 0 < v ≤ 1, 0 < x ≤ 1, 0 < y ≤ 0.5, 0 ≤ z ≤ 0.05, 0 < a ≤ 1, 0 < b ≤ 0.3, 0 ≤ c ≤ 3, 0 < d ≤ 1.8, 0 ≤ e ≤1.8; and - a light source configured to emit into the wavelength converting structure.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority of (i) U.S. Application No. 17/844,171 titled, "Phosphor Composition and Short Wavelength Infrared Emitting PCLEDS Emitting in the 1600-2200 NM Wavelength Range," filed June 20, 2022, and (ii) U.S. Application No. 63/235,523 titled "Phosphor Composition and Short Wavelength Infrared Emitting PCLEDS Emitting in the 1600-2200 NM Wavelength Range," filed August 20, 2021. FIELD OF THE INVENTION The disclosure relates generally to phosphor compositions for use in phosphor-converted light-emitting devices, and more particularly to phosphor compositions having broadband infrared emission in the 1600-2200 nm wavelength range. BACKGROUND Semiconductor light emitting diodes and laser diodes (collectively referred to herein as "LEDs") are among the most efficient light sources currently available. The emission spectrum of an LED typically exhibits a single narrow peak at a wavelength determined by the structure of the device and by the composition of the semiconductor materials from which it is constructed. By suitable choice of device structure and material system, LEDs may be designed to operate at ultraviolet, visible, or infrared wavelengths. LEDs may be combined with one or more wavelength converting materials (generally referred to herein as "phosphors") that absorb light emitted by the LED and in response emit light of a longer wavelength. For such phosphor-converted LEDs ("pcLEDs"), the fraction of the light emitted by the LED that is absorbed by the phosphors depends on the amount of phosphor material in the optical path of the light emitted by the LED, for example on the concentration of phosphor material in a phosphor layer disposed on or around the LED and the thickness of the layer. Phosphor-converted LEDs may be designed so that all of the light emitted by the LED is absorbed by one or more phosphors, in which case the emission from the pcLED is entirely from the phosphors. In such cases the phosphor may be selected, for example, to emit light in a spectral region that is not efficiently generated directly by an LED. Alternatively, pcLEDs may be designed so that only a portion of the light emitted by the LED is absorbed by the phosphors, in which case the emission from the pcLED is a mixture of light emitted by the LED and light emitted by the phosphors. By suitable choice of LED, phosphors, and phosphor composition, such a pcLED may be designed to emit, for example, light having a desired color temperature and desired color-rendering properties. CN 101 831 708 A relates to the field of laser crystal materials. It discloses a gadolinium gallium garnet which has a chemical formula of Cr:Tm:Gd3Ga5O12 which displays emission over the range of approx. 1800 to 2100 nm. The material comprises a cubic garnet host lattice. SUMMARY In one aspect, a wavelength converting structure is provided, the wavelength converting structure including an SWIR phosphor having emission wavelengths in the range of 1600 - 2200 nm, the SWIR phosphor comprising a structurally disordered garnet material, a sensitizer ion, and at least one rare earth emitter ion. The structurally disordered garnet material may include compositions derived from the structurally ordered gadolinium gallium garnet (Gd3)[Ga2]{Ga3}O12 with 8-fold coordinated Gd atoms, 6-fold coordinated Ga atoms, and 4-fold coordinated Ga atoms. The structurally disordered garnet material may include atoms that can occupy more than one lattice site. Gadolinium may be partially replaced by at least one of a rare earth element chosen from the group including Tm, Ho, La, Y, Yb, Nd, Er, and Ce. The rare earth emitter element may be a combination of Tm and Ho. The rare earth emitter element includes Tm. The SWIR phosphor includes (Gd3-u-v-x-y-zLuxTmyHozScvREu)[Sc2-a-b-d-eLuaCrbGad Ale]{Ga3-cAlc}O12 with RE = La, Y, Yb, Nd, Er, Ce and 0 ≤ u ≤ 2, 0 < v ≤ 1, 0 < x ≤ 1, 0 < y ≤ 0.5, 0 ≤ z ≤ 0.05, 0 < a ≤ 1, 0 < b ≤ 0.3, 0 ≤ c ≤ 3, 0 < d ≤ 1.8, 0 ≤ e ≤ 1.8. The non-doped host lattice of the SWIR phosphor may include (Gd,Lu,Sc)3[Sc,Lu,Ga,Al])2{Ga,Al}3O12 crystallizing in the structurally disordered cubic garnet structure type. The SWIR phosphor may include at least one of Gd2.367Ho0.01Tm0.152Sc1.6Lu0.27Ga1.8Al1.78Cr0.04O12, Gd2.59Tm0.24Ho0.02Sc0.75Lu0.3Ga2Al2Cr0.1O12, Gd2Ho0.013Tm0.2Sc0.67Lu0.24Ga1.6Al3.2Cr0.08O12 and Gd2.67Ho0.01Tm0.17Sc1.8Lu0.3Ga2AlCr0.05O12. The wavelength converting structure may further include an additional IR phosphor having emission in the wavelength range of 1100-1700 nm. The additional IR phosphor may include one or more of Ni2+, or Ni2+ and Cr3+ doped spinel, perovskite, and garnet type IR phosphor emitting in the 1000-1700 nm range. An example is a Ni2+ and Cr3+ doped garnet phosphor of composition (Gd)3[Sc, Ga, Ni, Zr, Cr]2{Ga,Al}3O12 for example Gd3Ga3.7ScAl0.18Ni0.02Zr0.021Cr0.1O12 and Gd3Ga4.7Al0.18Ni0.02Zr0.021Cr0.1O12. In another aspect, a luminescent material that emits lightin