WO2015177327A1

WO2015177327A1 - Infrared led

Info

Publication number: WO2015177327A1
Application number: PCT/EP2015/061351
Authority: WO
Inventors: Beata MALYASA; Thomas JÜSTEL; Dominik Uhlich; Ines Becker; Helga Bettentrup
Original assignee: Tailorlux Gmbh
Priority date: 2014-05-23
Filing date: 2015-05-22
Publication date: 2015-11-26
Also published as: DE102014107321A1; CN106661447A; DE102014107321B4

Abstract

The invention relates to a light-emitting device and to the use of said light-emitting device.

Description

Infrared LED

description

The invention relates to a light emitting device and the use of the light emitting device.

It is known to dope semiconductor materials with Cr ³⁺ . Thus AgCl crystals are doped in order to obtain, for example, line emissions (Kunze, I, and P. Smith "relaxation of Fehlstellendipolen in AgCl crystals II Results of AgCl:..., Ti ^3+, AgCl: V ³⁺ and AgCl: Cr ^{3 +} . "physica Status solidi (b) 38.1 (1970): 271-276). Al 2 O 3 was also doped with Cr ³⁺ at cryogenic temperatures to study cross-relaxation (Cremer, R. "Investigation of the cross-relaxation of Cr ³⁺ ions in Al 2 O 3." Physica Status solidi (b) 42.2 (1970): 507-521) ,

Also, infrared LEDs are known, which so far have a line emission in the infrared range.

US 201 0/0320480 A1 describes an ionic converter material for I R LEDs. WO 2012/1 59556 A1 describes a powdered ionic LED material.

WO 201 3/169364 A1 describes the microbiological production of ionic spinel.

The object of the present invention is to provide a technology with which efficient light sources with broadband emission in the infrared range can be made available.

In a first embodiment, the object underlying the invention is achieved by a light-emitting device which has a broadband infrared light emission comprising a light emitting part and a phosphor capable of absorbing a part of the light emitted from the light emitting part and emitting light of a wavelength different from that of the absorbed light, wherein a) the phosphor in the host lattice has at least one metal or semiconductor element which is not chromium, b) 0, 1 to 10 mol% of the atoms of the at least one metal or semiconductor element of the luminescent substance are replaced by chromium, and c) the luminescent substance is a semiconductor substance selected from borate, aluminate, gallate, germanate, vanadate, oxynitride, sulfide, silicate, sulfate, phosphate, molybdate, tungstate, oxide or mixtures thereof.

It has been found that for the first time broadband light sources in the near infrared range can be realized here.

Preferably, the light-emitting device is an LED (light-emitting diode).

Preferably, the light-emitting device is provided as described in EP 0 936 682, unless features are described differently in the present description.

fluorescent

The phosphor preferably contains at least 75 mol% of the metal atoms Al (aluminum). The phosphor is preferably a borate or aluminate. Preferably, 0.5 to 3 mol% of the atoms of the at least one metal or semiconductor element of the phosphor are replaced by chromium, particularly preferably exclusively Al atoms by chromium.

Chromium is preferably present in the oxidation state 3+. This is well suited since it exhibits high PL quantum yields as an activator ion, for example in aluminates or gallates, and furthermore has an energy level diagram as [Ar] 3d ³ -lon, which on the one hand favors emission transitions in the NI R range and on the other hand Position of these transitions by the crystal field strength D _q and the Racah parameter B (covalent character) makes it easy to adjust. For a broadband emission in the NI R range (for example, ⁴ T2g - ⁴ A2g), for example, Cr ³⁺ phosphors are needed, in which the Cr ^{3+ is} in a place with a weak crystal field, for example, a tetrahedral space.

It has surprisingly been found that some of the Cr ³⁺ -doped radiation converters, such as YAl 3 (BO 3) 4: Cr and GdAl 3 (BO 3) 4: Cr, have very little thermal quenching, which is of particular importance for use in semiconductor LEDs Significance is because the chip temperature can be up to 200 ° C. Accordingly, phosphors having a lower thermal quenching temperature may not be suitable for use in these LEDs. For illustration, Fig. 21 shows a Tanabe-Sugano diagram of a d ³ system (for example, Cr ³⁺ [Ar] 3d ³ ).

The operating temperature of the phosphor is preferably in a range of 1 0 ° C to 400 ° C. The phosphor preferably has the formula

M m M ² n (M ³ oCr _P ) _q Ar (formula I) where M ^{1 is} an alkaline earth metal, transition metal or lanthanide, where M ^{2 is} an alkaline earth metal, where M ^{3 is} Al, Ga, In, Ge, or Sc, where A is an anion, where m is a number in the range of 1 to 2, where n is a number in the range of 0 to 1, where o is a number in the range of 0.9 to 0.999, where p is a number in Range from 0.001 to 1, where q is a number in the range of 2 to 1 5, and where r is a number in the range of 3 to 20.

The anion preferably has a charge of -2. The anion is preferably selected from borate or oxygen. M ¹ is preferably selected from Gd, Y, Lu, Ca, Sr, La or Ba.

M ² is preferably Mg. The number n can then be 1, for example.

The phosphor is preferably selected from the group YAl3 (B03) 4, LaAl ₃ (B0 ₃ ) 4, GdAl ₃ (B0 ₃ ) 4, LuAl ₃ (B0 ₃ ) ₄ , YGa ₃ (B0 ₃ ) ₄ , LaGa ₃ (B0 ₃ ) ₄ , GdGa ₃ (B0 ₃ ) 4, LuGa ₃ (B0 ₃ ) 4, Yln ₃ (B0 ₃ ) 4, Laln ₃ (B0 ₃ ) 4, Gdln ₃ (B0 ₃ ) 4, Luln ₃ (B0 ₃ ) 4, YSc ₃ (B0 ₃ ) 4, LaSc ₃ (B0 ₃ ) 4, GdSc ₃ (B0 ₃ ) 4, LuSc ₃ (B0 ₃ ) 4, SrAh ₂ 0i 9, CaAli20i9, BaAli20i 9, LaMgAln Oi g, Zn ₃ Ga2Ge40i4, La ₃ GasGeOi4, La5GasSiOi4, LilnGe04, Mg ₂ Si04, A Mooe, AI2M02O9, AI ₂ Mo ₃ Oi2, AI2WO6, AI2W2O9, AI ₂ W ₃ 0I2, SC2M0O6, SC2M02O9, Sc2Mo ₃ O 2, SC2WO6, SC2W2O9, Sc2W ₃ 0i2, wherein all the aforementioned substances are doped with 0, 1 to 10 mol% chromium.

The phosphor is preferably excited by radiation in the range from 250 to 750 nm, in particular in the range between 400 and 650 nm.

The phosphor is preferably located within a luminescence conversion screen (eg, powder layer, ceramic, glass-ceramic, monocrystal, or powder-polymer composite) of the light-emitting device. This luminescence conversion screen may be part of an LED. The phosphor is intended, for example, to convert the spectrum of the light-emitting part (with an emission of, for example, 300-500 nm) into a broadband NI R spectrum.

The phosphor is preferably in particulate form. The median d50 of the particle size is preferably in a range of 1 to 20 μιτι, most preferably in a range of 5 to 8 μηι. The particle size can be measured by means of laser scattering. If the diameter is lower, the conversion efficiency can collapse.

The phosphor preferably has a high stability with respect to high radiation powers. The radiant power Φ in watts is described by DI N 5031 -1 as the quotient of the radiant energy Q and the time t: dQ

φ = -

dt

Since LEDs are almost punctiform radiators similar to laser diodes, consideration of the solid angle can be neglected. For example, a high power LED OS RAM for projection application (LE B P3W-GYHX-24) has a radiated power with IF = 6,000 mA 21,000 to 33,000 mW. The determination of these parameters can be done via a power meter. Preferably, the phosphor has a stability to high radiation powers in so far as that the decrease in the brightness of the phosphor after 1 000 operating hours does not decrease more than 20% of the output power in the endurance test. This stability measurement can be carried out, for example, according to the known methods at 85 ° C. under 85% atmospheric humidity under continuous load with 1 W radiation power (see also LH Cho, G. Anoop, DW Suh, SJ Lee, JS Yoo, On the stability and reliability of Sr1 -xBaxSi202N2: Eu2 + phosphors for white LED applications, Opt. Mater. Express. 2 (2012) 1292-1305. doi: 10.1364 / OME.2.001292). The phosphor preferably has a chemical resistance, in particular also to water and CO2. The resistance of the converter materials, as well as a complete ready-made LED are, for example, long-term tested by stability tests at 80 ° C and 80% humidity and this influence is evaluated over the duration of the test. Preferably after two days immersion in 5 wt.% Hydrochloric acid no decrease in the radiant power.

The phosphor preferably has a high absorption in the emission maximum of the light-emitting part. The reflectance of the phosphor is preferably in a range of 75% to 5%, preferably in a range of 30% to 5%, in the wavelength range of the light emission of the excitation element. The reflection of powders is characterized for example by the diffuse scattering of the particles, so that the reflection within an integrating sphere has to be measured for the determination, so that angle-dependent effects are excluded. For this purpose, for example, the excitation and emission modulator are tuned synchronously and the spectrum of the sample is divided by the spectrum of the white standard (BaS04) (see Luminescence properties of Eu3 + doped tungstates, dissertation by Helga Bettentrup, University of Osnabrück, Steinfurt, October 2009).

In general, A + T + R = 1 with the absorption A, the transmission T and the reflection R.

The phosphor preferably has a quantum yield in a range of 30 to 100%, preferably 80% to 100%. The quantum yield is determined according to DI N 5031 -9, under luminescence quantum yield η ρ with

_ Φρ (α ^η )

' ^{ρ ~} m where <t> p (em) is the emitted and when <t> p (abs) is the absorbed photons. Preferably within the light-emitting device at least one further phosphor is present, which is different from the first phosphor. This at least one further phosphor is preferably an aluminate, garnet, silicate, nitride or oxynitride. This at least one further phosphor preferably emits light in a range from 400 to 1800 nm. More preferably at least two further phosphors are present.

For example, Figure 23 shows an emission spectrum of a phosphor converted LED made with a yellow garnet phosphor, a red nitride phosphor, and a claimed NI R phosphor.

Wirtsqitter

The host lattice of the phosphor is preferably covalent. The covalent character or else nephelauxetic effect can be described, for example, by an electronegativity difference.

Preferably, the electronegativity difference in the host lattice of the phosphor Δχ is in a range of 0 to 1.5. This can be determined by conventional methods (see L. Pauling, The Nature of the Chemical Bond and the Structure of Molecules and Crystals: An Introduction to Modern Structural Chemistry, Cornell University Press, 1960).

The outlying d electrons in the metal atom of the material of the phosphor such as Al are preferably delocalized. This means that the energy difference between the most energetic outboard d orbital and the lowest energy d orbital is preferably between 10,000 to 30,000 cm ^-1 . This energy difference can be determined by evaluating the fluorescence spectra.

However, a general estimation in advance is often difficult, since the strength of the splitting depends strongly on the crystal system and thus we are often evaluated by the experimental proof. Reason- In addition, the splitting is based on the Schrödinger equation (see E. Schrödinger, Quantization as eigenvalue problem, Ann. Phys. 384 (1926) 361- 376. doi: 10.1002 / andp.19263840404) with which the complex wave function of a point particle in a potential V can be described. Derived from this equation, the electron distributions of a perfect material could be predicted.

22 illustrates the different splits of the d orbitals as a function of their crystallographic position, so that a theoretical statement can only be supported by time-consuming and highly complex calculations (compare JE Huheey, R. Keiter, R. Keiter, Inorganic Chemistry, Principles of Structure and Reactivity, De Gruyter, Berlin, Boston, 2003.).

As a rule, a stronger splitting is observed when d orbitals are farther from the nucleus. The crystal field splitting of the material of the phosphor is preferably low. The crystal field splitting is at most 2 D _q derived from the Tanabe-Sugano diagram for d ³ ions (Figure 21). This is also described in standard textbooks (see JE Huheey, R. Keiter, R. Keiter, Inorganic Chemistry, Principles of Structure and Reactivity, De Gruyter, Berlin, Boston, 2003) and can be demonstrated by calculation but also by practical experiments.

The ^Stokes' shift of the specific material of the phosphor is preferably high. The energy difference between the maximum of the excitation and emission band is referred to for example as ^Stokes' sche shift. This ^Stokes' sche shift can be determined by conventional methods.

A host lattice with spinel structure or garnet structure may be disadvantageous in certain circumstances, since these have a weak covalent character depending on their composition. Spinel compounds are usually of low covalent character and are more ionic. As a result, spinel structures generally produce line emissions instead of the desired broadband emissions. Spinel compounds are therefore not preferred as the phosphor.

Metal or semi-conductor element

The metal or semiconductor element is preferably a metal element. Preferably, only the metal element is replaced by chromium.

Preferably, the at least one metal or semiconductor element is a Group 1 3 element.

Preferably, the at least one metal or semiconductor element has tetrahedral coordination in the host lattice.

Preferably, this is at least one metal or semiconductor element - for example M ³ - Al, Ga, In, Tl, Ge, Zn, Sn or Si and most preferably Al.

More metal

Preferably, at least one further metal is present in addition to the at least one metal or semiconductor element and in particular the group 1 3 element. This further metal is preferably selected from alkaline earth metals, transition metals, lanthanides.

Particularly suitable elements are those which are stable as redox ions in the oxidation states +2 and +3.

The further metal is preferably selected from Mg, Ca, Sr, Ba, Y, Gd, La, Lu or mixtures thereof. From the other metal so for example, two different metals may be present. For example, in addition to aluminum as a metal or semi-conductor element as a further metal Ba and additionally Mg may be present. bandwidth

The phosphor preferably emits light having a conversion rate of emitted to absorbed photons of at least 10%. In addition, the energy distribution of the emission spectrum must preferably match the application, which is a band width of the emission of at least 10 nm, preferably 50 nm to 100 nm or even greater.

The phosphor preferably emits light over a wavelength range having a width of at least 50 nm in a range between 750 nm and 1800 nm, preferably in the range 850 to 1000 nm.

The phosphor preferably emits light having an intensity of at least 10% relative to the maximum emission over the entire range of at least 750 nm to 800 nm under otherwise identical conditions. Preferably, the light emission of the phosphor is given by a relaxation from an excited state with a spin multiplicity 2S + 1 of 4.

The phosphor preferably emits between 650 and 1800 nm.

Thermal extinction

The phosphor preferably has a low thermal quenching. This was for example by V. Bachmann et.al. on the basis of (Ca, Sr, Ba) Si202N2: Eu ²⁺ extensively studied (see verse Bachmann, C. Ronda, O. Oeckler, W. Schnick, A. Meijerink, Colorpoint tuning for (Sr, Ca, Ba. ) Si202N2: Eu2 + for White Light LEDs, Chemistry of Materials (2009) 316-325.). The quantification of the thermal quenching takes place, for example, by the temperature-dependent recording of emission spectra, which, however, also by the consideration of the absolute intensity in the emission maximum can be represented by considering the emission integrals. The value TQ1 / 2 or also TQ50 describes the intensity at which only 50% of the intensity after warming up of 0 K is present. The sooner the thermal quenching starts, the worse it is for use as a converter material in LED applications, since here the operating temperatures are between 100 and 200 ° C in chip proximity. TQ 50 is preferably at least 400 ° C for the phosphor of the present invention.

Further Embodiments In a further embodiment, the object underlying the invention is achieved by a broadband radiator in the near infrared range, which has a light-emitting device according to the invention.

In a further embodiment, the object underlying the invention is achieved by a heat cabin having a broadband radiator according to the invention.

In a further embodiment, the object underlying the invention is achieved by the use of the device according to the invention for the non-invasive determination of blood constituents, analytical purposes, heat therapy, improved wound healing, pain therapy, food monitoring, heat cabins, safety detectors, motion detectors, and detectors in ATMs.

embodiments

General: X-ray powder diffractograms were measured by conventional methods, measured in reflection on a Rigaku type MiniFlex II powder diffractometer with Bragg-Brentano geometry. The X-ray source was a copper X-ray tube with Κ-radiation of wavelength 0, 1 5413 nm with a Tube voltage of 30 kV and a tube current of 10 mA used. All diffractograms were measured in the angular range 2Θ 10 to 80 ° in 0.02 ° increments.

Emission spectra were measured by conventional methods as described, for example, by JR Lakowicz in Principles of Fluorescence Spectroscopy (see JR Lakowicz, Principles of Fluorescence Spectroscopy, Edition: 3rd ed., 2006 Corr. 5th printing 2010, Springer, New York, 2010). , The reported emission spectra were recorded on a fluorescence spectrometer from Edinburgh Instruments FLS 920 in a powder sample holder with mirror optics. The spectra were excited at the absorption maximum and measured in the wavelength range from 450 to 1000 nm in 1 nm increments.

Excitation spectra were measured by conventional methods as described by J.R. Lakowicz (see J. R. Lakowicz, Principles of Fluorescence Spectroscopy, ed., 3rd Ed., 2006, Corr., 5th printing, 2010, Springer, New York, 2010). All excitation spectra were recorded with a fluorescence spectrometer from Edinburgh Instruments type FLS 920 in the wavelength range between 250 and 650 nm in 1 nm increments. As detection wavelength, the emission maximum of the examined samples was selected.

Reflectance spectra were measured by conventional methods on the Edinburgh Instruments Model FS920 fluorescence spectrometer in a BaSÜ4 coated Ulbricht sphere against a white standard (BaSÜ4). All spectra were recorded in 1 nm increments at synchronously tuned excitation and emission monochromators and divided by the white standard. Among others, the method of recording reflectance spectra by C. Ronda is described in Luminecence: From Theory to Application (see P. Vergeer, Experimental Techniques, in: C. Ronda (Ed.), Luminescence, Wiley-VCH Verlag GmbH & Co. KGaA, 2007: pp. 219-250.). The recording and evaluation of thermal quenching curves, for example, by V. Bachmann et.al. Detailed examination of (Sr, Ca, Ba) Si202N2: Eu ²⁺ (see V. Bachmann, C. Ronda, O. Oeckler, W. Schnick, A. Meijerink, Color Point Tuning for (Sr, Ca, Ba) Si202N2: Eu2 + for White Light LEDs, Chemistry of Materials (2009) 316-325.). The measurements of the embodiment attached hereto were made on a fluorescence spectrometer from Edinburgh instruments with built-in cryostat Oxford Instruments in a temperature range of 75 to 500 K. After Temperaturstbilisierung also emission spectra under excitation at the excitation maximum in the wavelength range between 450 and 1 1 nm steps performed. Forming the emission integral and fitting the curve via a Boltzmann sigmoid function in the range 0 to 1 reflect the quenching temperature of TQ1 / 2. Unless stated otherwise, the light-emitting device according to the invention was produced by customary methods and methods, as described, for example, in the exemplary embodiments and the description of EP 0 936 682.

a) YAI ₃ (BO ₃ ) 4: Cr (0.1-10%)

Y2O3 + 3 (1-x) Al2O3 + 3x Cr ₂ O ₃ + 4 H 3BO3 -> 2 Y (Ali-x Crx) ₃ (BO3) 4 + 6 H2O synthesis

The educts were thoroughly mixed in an agate mortar and then transferred to a corundum crucible. In a first calcination step, the mixture was dehydrated for 2 h at 500 ° C. Then it was again crushed and the mixture calcined for 4 h at 1200 ° C, forming the target phase. Show it:

Fig. 1: X-ray powder diffraction of Y (Alo.9sCro.02) 3 (603) 4 for Cu

Kalpha radiation Fig. 2: Emission spectrum of Y (Alo.98Cro.02) 3 (803) 4 at 425 nm excitation

Fig. 3: Excitation spectrum of Y (Alo.98Cro.o2) 3 (BO3) 4 for 720 nm

Emission Fig. 4: Reflectance spectrum of Y (Alo.98Cro.o2) 3 (BO3) 4 versus BaSÜ4 as

White standard

Fig. 4a quench curve of Y (Alo.99Cro.oi) 3 (BO3) 4

b) GdAI ₃ (BO ₃₎ 4: Cr (0.1 - 10%), Gd2O3 + 3 (1-x) Al2O3 + Cr2O3 3x + 4 H 3BO3

2 Gd (Ali-x Crx) ₃ (BO3) 4 + 6 H2O

synthesis

The educts were thoroughly mixed in an agate mortar and then transferred to a corundum crucible. In a first calcination step, the mixture was dehydrated for 2 h at 500 ° C. Then it was again crushed and the mixture calcined for 4 h at 1200 ° C, forming the target phase. Show it :

Fig. 5: X-ray powder diffractogram of Gd (Alo.9sCro.02) 3 (603) 4 for Cu

Kalpha radiation

Fig. 6: Emission spectrum of Gd (Alo.9sCro.02) 3 (603) 4 at 420 nm

stimulation

Fig. 7: Excitation spectrum of Gd (Alo.9sCro.02) 3 (603) 4 for 720 nm

Emission Fig. 8: Reflectance spectrum of Gd (Alo.9sCro.02) 3 (603) 4 against BaSÜ4 as white standard c) Ba g Alio Oi ₇ : Cr (0.1-10%)

BaCOs + MgO + 5 (1-x) Al ₂ O ₃ + 5xCr ₂ O ₃ - BaMg (Ali _-x Cr _x ) ioOi7 + CO2

synthesis

The educts were thoroughly mixed in an agate mortar and then transferred to a corundum crucible. The mixture was then calcined for 5 hours at 1250 ° C to form the target phase. Show it:

Fig. 9: X-ray powder diffractogram of BaMg (Alo.99Cro.oi) ioOi7 for

Cu Kalpha radiation

10: Emission spectrum of BaMg (Alo.99Cro.oi) ioOi7 at 420 nm

stimulation

Figure 11: Excitation spectrum of BaMg (Alo.99Cro.oi) ioOi7 for 720 nm

emission

Fig.12: Reflectance spectrum of BaMg (Alo.99Cro.oi) ioOi7 versus BaSÜ4 as white standard

d) La gAliiOi ₉ : Cr (0.1-10%)

0.5La2Os + MgO + 5.5 (1-x) Al ₂ O 3 + ₂ 5.5xCr O3 - LaMg (Ali _-x Cr _x) synthesis iiOi9

The educts were thoroughly mixed in an agate mortar and then transferred to a corundum crucible. Then, the mixture was calcined at 1400 ° C for 5 hours to form the target phase. Show it:

Fig. 13: X-ray powder diffractogram of LaMg (Alo.98Cro.o2) Oi9 for

Cu Kalpha radiation Fig.14: Emission spectrum of LaMg (Alo.98Cro.o2) nOi9 at 460 nm

stimulation Excitation spectrum of LaMg (Alo.98Cro.o2) O i 9 for 720 nm emission

Reflection spectrum of LaMg (Alo.98Cro.o2) n Oi 9 versus BaSÜ4 as white standard

e) SrAli ₂ Oi ₉ : Cr (0.1-10%)

SrCOs + 6 (1 -x) Al ₂ O ₃ + 6xCr ₂ O ₃ - Sr (Al i _-x Cr _x ) i 20i 9 + CO2 Synthesis

Fig. 17: X-ray powder diffractogram of Sr (Alo.9sCro.02) 12019 for Cu

Kalpha radiation

FIG. 18: Emission spectrum of Sr (Alo.9sCro.02) 12019 at 420 nm excitation

Fig. 19: Excitation spectrum of Sr (Alo.9sCro.02) 12019 for 720 nm emission

Fig. 20: Reflectance spectrum of Sr (Alo.9sCro.02) 12019 versus BaS4

White standard

The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

Claims

claims

1 . A light-emitting device which enables broad-band light emission in the infrared region and contains a light-emitting part and a phosphor capable of absorbing a part of the light emitted from the light-emitting part and emitting light of a wavelength different from that of the light absorbed in which a) the phosphor in the host lattice has at least one metal or semiconductor element which is not chromium, b) 0, 1 to 10 mol% of the atoms of the at least one metal or semiconductor element of the luminescent substance are replaced by chromium, and c) the phosphor is a semiconductor substance selected from borate, aluminate, gallate, germanate, vanadate, oxynitride, sulfide, silicate, sulfate, phosphate, molybdate, tungstate, oxide or mixtures thereof.

2. Light-emitting device according to claim 1, characterized in that the at least one metal or semiconductor element is a Group 1 3 element.

3. Light-emitting device according to claim 1 or 2, characterized in that the at least one metal or Halbeiterelement has tetrahedral coordination in the host lattice.

4. Light-emitting device according to one of claims 1 to 3, characterized in that the electronegativity difference in the host lattice of the phosphor Δχ is in a range of 0 to 1.5.

5. Light-emitting device according to one of claims 1 to 4, characterized in that the phosphor has the formula m ² n ( ³ oCr _P ) _q Ar (formula I), wherein M ^{1 is} an alkaline earth metal, transition metal or lanthanide, wherein M ^{2 is} an alkaline earth metal. wherein M ^{3 is} Al, Ga, In, Ge, or Sc, wherein A is an anion, where m is a number in a range of 1 to 2, where n is a number in the range of 0 to 1, where o is a number is in the range of 0.9 to 0.999, where p is a number in the range of 0.001 to 1, where q is a number in the range of 2 to 1 5, and where r is a number in the range of 3 to 20.

6. A light-emitting device according to any one of claims 1 to 5, characterized in that the phosphor emits light with intensity of emission of at least 10% at 800 nm relative to the maximum emission.

7. Light-emitting device according to one of claims 1 to 6, characterized in that the at least one metal or Halbeiterelement has tetrahedral coordination in the host lattice.

8. Light emitting device according to one of claims 1 to 7, characterized in that at least one further metal in addition to the at least one metal or Halbeiterelement, more preferably M ¹ , is included.

9. A light emitting device according to any one of claims 1 to 8, characterized in that there are one or more phosphors different from the first phosphor.

10. Light-emitting device according to one of claims 1 to 9, characterized in that the phosphor is in the form of particles, which particularly preferably have a diameter in the median d50 in a range of 1 to 20 μηι.

1 1. A near infrared broadband radiator having a light emitting device according to any one of claims 1 to 10.

12. Use of the light-emitting device according to one of claims 1 to 10 for the noninvasive determination of blood constituents, analytical purposes, heat therapy, improved wound healing, pain therapy, food monitoring, heat cabins, safety detectors, motion detectors, and detectors in ATMs.