PHOSPHOR PROCESS FOR PRODUCING A PHOSPHOR AND OPTOELECTRONIC DEVICE

Abstract

A phosphor having the general formula EA.sub.7A.sub.2T1.sub.t1T2.sub.t2 T3.sub.t3N.sub.nO.sub.o:RE. EA is selected from the group of divalent elements. A is selected from the group of monovalent elements. T1 is selected from the group of trivalent elements. T2 is selected from the group of tetravalent elements. T3 is selected from the group of pentavalent elements. RE is an activator element. 16+3 t1+4 t2+5 t3−3n−2 o=0. t1+t2+t3=5; n+o=16; 0≤t1≤4; 0≤t2≤5; 0≤t3≤5; 0≤n≤9; 7≤o≤16.

Claims

1. A phosphor having the general formula EA.sub.7A.sub.2T1.sub.t1T2.sub.t2T3.sub.t3N.sub.nO.sub.o:RE, wherein EA is selected from the group of divalent elements, A is selected from the group of monovalent elements, T1 is selected from the group of trivalent elements, T2 is selected from the group of tetravalent elements, T3 is selected from the group of pentavalent elements, RE is an activator element, 16+3 t1+4 t2+5 t3−3 n−2 o=0, and t1+t2+t3=5; n+o=16; 0≤t1≤4; 0≤t2≤5; 0≤t3≤5; 0≤n≤9; 7≤o≤16.

2. The phosphor according to claim 1, further comprising a host lattice with a structure comprising AO.sub.4 tetrahedra and at least one of the following tetrahedra selected from the group comprising: T1(O,N).sub.4 tetrahedra, T2(O,N).sub.4 tetrahedra, T3(O,N).sub.4 tetrahedra, and combinations thereof.

3. The phosphor according to claim 2, wherein the tetrahedra of the host lattice are each linked via a corner.

4. The phosphor according to claim 2, wherein the at least one tetrahedron selected from the group comprising T1(O,N).sub.4 tetrahedron, T2(O,N).sub.4 tetrahedron, T3(O,N).sub.4 tetrahedron, and combinations thereof is linked via a corner to at least one further tetrahedron selected from the group comprising T1(O,N).sub.4 tetrahedron, T2(O,N).sub.4 tetrahedron, T3(O,N).sub.4 tetrahedron, and combinations thereof.

5. The phosphor according to claim 3, wherein the tetrahedra linked via the corner form channels where at least one EA atom is located.

6. The phosphor according to claim 1, wherein the general formula EA.sub.7A.sub.2T1.sub.t1T2.sub.t2T3.sub.t3N.sub.nO.sub.o:RE is EA.sub.7A.sub.2Si.sub.5N.sub.4O.sub.12:RE.

7. The phosphor according to claim 6, wherein EA comprises one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, and combinations thereof.

8. The phosphor according to claim 6, wherein A comprises one or more elements selected from the group consisting of Li, Na, K, Rb, Cs, and combinations thereof.

9. The phosphor according to claim 6, wherein RE comprises one or more elements selected from the group consisting of rare earth elements, manganese, chromium, nickel, and combinations thereof.

10. The phosphor according to claim 6, wherein the general formula EA.sub.7A.sub.2T1.sub.t1T2.sub.t2T3.sub.t3N.sub.nO.sub.o:RE is (EA.sub.1-aRE.sub.a).sub.7A.sub.2Si.sub.5N.sub.4O.sub.12, wherein a ranges from 0.001, inclusive to 0.1, inclusive.

11. The phosphor according to claim 6, wherein the general formula EA.sub.7A.sub.2T1.sub.t1T2.sub.t2T3.sub.t3N.sub.nO.sub.o:RE is Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:RE.

12. The phosphor according to claim 2, wherein the host lattice of the phosphor comprises a structure with a monoclinic space group.

13. A process for producing a phosphor having the general formula EA.sub.7A.sub.2T1.sub.t1T2.sub.t2T3.sub.t3N.sub.nO.sub.o:RE, wherein the process comprises: providing reactants comprising EA.sub.2N, EAO, A.sub.2CO.sub.3, T1.sub.2O.sub.3, T2O.sub.2, T3.sub.2O.sub.5, RE.sub.2O.sub.3, and combinations thereof; heating the reactants to a temperature ranging from 800° C., inclusive to 1200° C., inclusive; wherein: EA is selected from the group of divalent elements; A is selected from the group of monovalent elements; T1 is selected from the group of trivalent elements; T2 is selected from the group of tetravalent elements; T3 is selected from the group of pentavalent elements; RE is an activator element; 16+3t1+4t2+5t3−3n−2o=0; and t1+t2+t3=5; n+o=16; 0≤t1≤4; 0≤t2≤5; 0≤t3≤5; 0≤n≤9; 7≤o≤16.

14. The process for producing a phosphor according to claim 13, wherein EA.sub.2N is Sr.sub.2N, EAO is SrO, A.sub.2CO.sub.3 is Li.sub.2CO.sub.3, and RE.sub.2O.sub.3 is Eu.sub.2O.sub.3.

15. An optoelectronic device comprising: a semiconductor chip configured to emit electromagnetic radiation of a first wavelength range from a radiation exit surface; a conversion element comprising a phosphor according to claim 1 configured to convert electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range.

16. The optoelectronic device according to claim 15, wherein an emission maximum of the phosphor ranges from 500 nanometers, inclusive to 550 nanometers, inclusive.

17. The optoelectronic device according to claim 15, wherein a dominant wavelength of the phosphor ranges from 555 nanometers, inclusive to 575 nanometers, inclusive.

18. The optoelectronic device according to claim 15, wherein a FWHM width of the phosphor ranges from 170 nanometers, inclusive to 190 nanometers, inclusive.

19. The optoelectronic device according to claim 15, wherein a further phosphor is absent; and is configured to emit electromagnetic radiation having a correlated color temperature ranging from 9000 K, inclusive to 10000 K inclusive.

20. The optoelectronic device according to claim 15, further comprising a further phosphor configured to convert electromagnetic radiation of the first wavelength range into electromagnetic radiation of a third wavelength range and electromagnetic radiation having a correlated color temperature ranging from 3000 K, inclusive to 5000 K, inclusive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The accompanying drawings serve to provide an understanding of non-limiting embodiments. The drawings illustrate non-limiting embodiments and, together with the description, serve for explanation thereof. Further non-limiting embodiments and many of the intended advantages will become apparent directly from the following detailed description.

[0088] FIG. 1 a section of the host lattice of the phosphor Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ in viewing direction b according to an exemplary embodiment,

[0089] FIG. 2 a section of the host lattice of the phosphor Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ in viewing direction b according to an exemplary embodiment,

[0090] FIG. 3 a section of the host lattice of the phosphor Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ in viewing direction c according to an exemplary embodiment,

[0091] FIG. 4 and FIG. 5 a section of the host lattice of the phosphor Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ according to an exemplary embodiment,

[0092] FIG. 6 a schematic sectional view for different process stages of a process for producing a phosphor according to an exemplary embodiment,

[0093] FIG. 7, FIG. 8 and FIG. 9 a schematic sectional view of an optoelectronic device according to an exemplary embodiment each,

[0094] FIG. 10 two emission spectra of the phosphor Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ according to an exemplary embodiment upon excitation with primary wavelengths of the semiconductor chip of about 408 nanometers and about 448 nanometers,

[0095] FIG. 11 emission spectra of Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ and a conventional phosphor with comparable dominant wavelength,

[0096] FIG. 12 a color rendering index as a function of a primary wavelength of the blue emitting semiconductor chip for various optoelectronic devices with white color impression, and

[0097] FIG. 13 total emission spectra for various optoelectronic devices with white color impression with a primary wavelength of the semiconductor chip of about 445 nanometers.

[0098] Identical, similar or identically acting elements are provided in the figures with the same reference signs. The figures and the proportions of the elements shown in the figures with respect to each other are not to be regarded as true to scale. Rather, individual elements, in particular layer thicknesses, may be oversized for better representability and/or better understanding.

DETAILED DESCRIPTION

[0099] FIG. 1 shows a section of the host lattice of the phosphor 1 EA.sub.7A.sub.2T1.sub.t1T2.sub.t2T3.sub.t3N.sub.nO.sub.o:RE, in this case of the phosphor L1 Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ in a schematic representation according to an exemplary embodiment. The host lattice has a structure with a monoclinic space group C2. The structure of the host lattice has corner-linked T1(O,N).sub.4 tetrahedra and/or T2(O,N).sub.4 tetrahedra and/or T3(O,N).sub.4 tetrahedra and AO.sub.4 tetrahedra. Presently, the host lattice comprises T2(O,N).sub.4 tetrahedra with T2=Si, i.e. Si(O,N).sub.4 tetrahedra 8 and A(O,N).sub.4 tetrahedra with A=Li, i.e. LiO.sub.4 tetrahedra 9.

[0100] “Corner-linked” means here and in the following that two tetrahedra are connected by a common corner 10. The corner 10 can be either a common oxygen atom 6 or a common nitrogen atom 7. The structure of the phosphor L1 was determined using X-ray structure analysis measurements, examples of the results of which are shown in Table 1. In the FIGS. 1 to 5, not all tetrahedra and atoms are given a reference sign for the sake of clarity.

[0101] The Si(O,N).sub.4 tetrahedron 8 and/or the LiO.sub.4 tetrahedron 9 comprise a tetrahedral gap. The tetrahedral gap is a region inside the respective tetrahedron.

[0102] The oxygen atoms 6 and the nitrogen atoms 7 of the Si(O,N).sub.4 tetrahedron 8 span the tetrahedron, with the silicon atom 4 being located in the tetrahedral gap of the tetrahedron spanned by the oxygen atoms 6 and the nitrogen atoms 7. In a non-limiting embodiment, all atoms spanning the tetrahedron are at a similar distance from the silicon atom 4 located in the tetrahedral gap.

[0103] In the LiO.sub.4 tetrahedron 9, the oxygen atoms 6 span a tetrahedron and the lithium atom 3 is located in the tetrahedral gap of the tetrahedron spanned by the oxygen atoms 6.

[0104] At least one Si(O,N).sub.4 tetrahedron 8 and at least one LiO.sub.4 tetrahedron 9 are each linked to each other via an oxygen atom 6. The oxygen atom 6 linking the LiO.sub.4 tetrahedron 9 to the Si(O,N).sub.4 tetrahedron 8 is a common oxygen atom 6 of the LiO.sub.4 tetrahedron 9 and the Si(O,N).sub.4 tetrahedron 8. The Si(O,N).sub.4 tetrahedra 8 may likewise be linked to another Si(O,N).sub.4 tetrahedron 8 via a nitrogen atom 7. The nitrogen atom 7 linking the Si(O,N).sub.4 tetrahedron 8 to the further Si(O,N).sub.4 tetrahedron 8 is a common nitrogen atom 7 of the Si(O,N).sub.4 tetrahedra 8. The structure exhibits isolated strands formed in the present case by five Si(O,N).sub.4 tetrahedra 8 linked via common corners 10.

[0105] The Si(ON).sub.4 tetrahedra 8 and LiO.sub.4 tetrahedra 9 form channels 11 linked via a corner 10, in which at least one strontium atom 2 is located. The strontium atom 2 can be replaced by europium atoms 5 as activator element. The channels 11 are formed as cavities in the strands of corner-linked Si(O,N).sub.4 tetrahedra 8 and LiO.sub.4 tetrahedra 9.

[0106] Each Si(O,N).sub.4 tetrahedron 8 is linked via at least one LiO.sub.4 tetrahedron 9 to Si(O,N).sub.4 tetrahedra 8 of the same or the neighboring strand. This linkage results in layers of corners 10 linked Si(O,N).sub.4 8 and LiO.sub.4 tetrahedra 9 extending in the be plane, as shown in FIG. 2. The strontium atoms 2 and the europium atoms 5, respectively, occupy the channels 11 formed by Si(O,N).sub.4 8 and LiO.sub.4 tetrahedra 9.

[0107] FIG. 3 differs from FIG. 2 only in the direction of view. FIG. 2 extends in viewing direction b and FIG. 3 in viewing direction c.

[0108] Table 1 below shows the crystallographic data of the phosphor L1 Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+. For the monoclinic space group, the angles α and γ are equal to 90° and β, is not equal to 90°, and the lattice parameters a, b, and c differ. The mixed occupation of europium and strontium was not considered in the structure refinement due to the small atomic fraction of europium.

TABLE-US-00001 TABLE 1 Crystallographic data of Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+. Structure type Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12 Calculated composition Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ Crystal system monoclinic Space group C2 Lattice parameter a [Å] 22.979 (4)  b [Å] 5.5415 (9)  c [Å] 6.4773 (11) α [°] 90 β [°] 102.524 (7)   γ [°] 90 Volume [As] 805.2 (2) Density[ ρ/gcm.sup.−3] 2.519 T [K]   296 (2) Total reflections 4301 Independent reflections 1445 Number of refined parameters 132 Measured reciprocal space −27 ≤ h ≤27, −6 ≤ k ≤ 6, −7 ≤ 1 ≤ 7 R1, wR2 2.80%, 5.93% GooF 1.043 Δρ.sub.min, Δρ.sub.max [eÅ.sup.−3] −1.16/+0.91

[0109] Table 2 below shows atomic layer occupancies and isotropic deflection parameters for the phosphor L1 Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+.+.

TABLE-US-00002 Tabelle 2 Atomic positions, occupancies and isotropic deflection parameters for the phosphor L1 Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+. Wyck off Atoms position x y z Occupation U.sub.iso Sr01 2a 0.5 0.7537 (3) 0 1 0. 0071 (4) Sr02 4c 0.5714 (1) 0.2471 (2) 0.7556 (2) 1 0. 0090 (3) Sr03 4c 0.8640 (1) 0.3051 (2) 0.5627 (2) 1 0. 0084 (3) Sr04 4c 0.7793 (1) 0. 8261 (2) 0.8176 (2) 1 0. 0098 (3) Si05 2b 0.5 0. 6578 (8) 0.5 1 0.0063 (9) Si06 4c 0.6985 (1) 0.2974 (6) 0. 6772 (4) 1 0.0065 (6) Si07 4c 0.5871 (1) 0.3323 (7) 0.2539 (4) 1 0.0061 (6) O08 4c 0.6066 (4) 0.5221 (2) 0. 0789 (14) 1 0. 0097 (18) O09 4c 0.6913 (4) 0.5541 (18) 0.7970 (17) 1 0.011 (2) O10 4c 0.5519 (4) 0. 822 (2) 0.6545 (12) 1 0.0150 (17) O11 4c 0.6827 (5) 0. 0753 (18) 0.8291 (16) 1 0.010 (2) O12 4c 0.7673 (4) 0.2661 (17) 0. 6529 (13) 1 0.0155 (19) O13 4c 0.5689 (5) 0. 0774 (16) 0. 1288 (14) 1 0.015 (2) N14 4c 0.6482 (4) 0.279 (2) 0.4487 (14) 1 0.011 (2) N15 4c 0.5316 (5) 0.473 (2) 0.3408 (18) 1 0. 011 (2) Li16 4c 0.6431 (13) 0.754 (7) 0.914 (5) 1 0.031 (6)

[0110] FIG. 4 and FIG. 5 schematically show a corner-linked channel 11 of Si(O,N).sub.4 8 and LiO.sub.4 tetrahedra 9 from two different perspectives. In this case, the strontium atoms 2 and the europium atoms 5 are located in the channel 11.

[0111] In the process according to the exemplary embodiment of FIG. 6, reactants are provided in a first process step S1. These are selected from the following group: EA.sub.2N, EAO, A.sub.2CO.sub.3, T1.sub.2O.sub.3, T2O.sub.2, T3.sub.2O.sub.5 and RE.sub.2O.sub.3; present EA.sub.2N, EAO, A.sub.2CO.sub.3, SiO.sub.2 and RE.sub.2O.sub.3. The reactants are homogeneously mixed, then the mixture is transferred to an open nickel crucible, which is transferred to a tube furnace. In a second process step S2, the mixture is heated under a forming gas atmosphere (N.sub.2:H.sub.2=92.5:7.5), so as to ensure reducing conditions, or under a nitrogen atmosphere at a temperature between 800° C. and 1200° C., inclusive. The mixture is heated for about 24 hours. The phosphor L1 is prepared, for example, by mixing, homogenizing and heating the reactants Sr.sub.2N, SrO, SiO.sub.2, Li.sub.2CO.sub.3 and Eu.sub.2O.sub.3. The corresponding ratio of each reactant to each other is shown in Table 3 as an example. The low temperature compared to conventional phosphor production processes, such as garnet phosphors, leads to simplified production as well as improved energy efficiency.

TABLE-US-00003 Amount of substance Mass Phosphor L1 Reactant [mmol] [g] Sr.sub.2N 42.78 8.096 SrO 14.26 1.478 SiO.sub.2 71.30 4.284 Li.sub.2CO.sub.3 14.26 1.054 Eu.sub.2O.sub.3 0.2501 0.088

[0112] FIG. 7 shows a schematic sectional view of an optoelectronic device 12 comprising a semiconductor chip 13 which, in operation, emits electromagnetic radiation of a first wavelength range from a radiation exit surface 19. The electromagnetic radiation of the first wavelength range has an emission spectrum, which is also referred to as the emission spectrum of the semiconductor chip. For convenience, an emission maximum of the emission spectrum of the semiconductor chip is also referred to herein as a primary wavelength λ.sub.p. The semiconductor chip 13 includes an epitaxially grown semiconductor layer sequence having an active zone 17 capable of generating electromagnetic radiation. Further, the optoelectronic device 12 comprises an encapsulant 15. The encapsulant 15 having a transmissivity to electromagnetic radiation of at least the active zone 17 that is at least 85%, such as 95%. The semiconductor chip 13 is surrounded by the encapsulant 15. Likewise, the optoelectronic device 12 has a conversion element 14 with a phosphor L1 which converts electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range. The electromagnetic radiation of the second wavelength range comprises an emission spectrum, which is also referred to as the emission spectrum of the phosphor. The phosphor L1 is embedded in a matrix material. The matrix material is selected from the group of polysiloxanes. The conversion element 14 may be formed as a conversion layer.

[0113] The optoelectronic device 12 according to the exemplary embodiment of FIG. 8 comprises a semiconductor chip 13, a carrier element 16, an adhesive layer 18, and a conversion element 14. The conversion element 14 is arranged on the radiation exit surface 19 of the semiconductor chip 13 by means of an adhesive layer 18. However, the conversion element 14 may also be directly provided on the radiation exit surface 19 of the semiconductor chip 13. The surface of the semiconductor chip 13 opposite to the radiation exit surface 19 is arranged on a carrier element 16 for stabilization. The conversion element 14 is formed as a conversion layer and comprises the phosphor L1 embedded in the matrix material.

[0114] The conversion element 14 is free of another phosphor and emits electromagnetic radiation with a correlated color temperature CCT between 9000 K and 10000 K, inclusive. Thus, a cold white color impression is achieved with a high correlated color temperature CCT and a high color rendering index CRI of at least 80, such as at least 85, or at least 90. The electromagnetic radiation with the cold white color impression is obtained by a combination of the electromagnetic radiation of the first wavelength range emitted by the semiconductor chip 13 and the electromagnetic radiation of the second wavelength range emitted by the phosphor L1.

[0115] Compared to FIG. 8, the exemplary embodiment of FIG. 9 comprises a further phosphor LX in the conversion element 14.

[0116] The further phosphor LX may be, for example, a garnet phosphor or a nitride phosphor. In a non-limiting embodiment, the phosphor is a red-emitting phosphor. For example, nitride phosphors, for example (Ba,Sr,Ca)AlSiN.sub.3:Eu, Sr(Sr,Ca)Al.sub.2Si.sub.2N.sub.6:Eu, (Ca,Sr,Ba)Si.sub.2O.sub.2N.sub.2:Eu and (Ca,Sr,Ba).sub.2Si.sub.5N.sub.8:Eu are used as red-emitting phosphors. In a non-limiting embodiment, (Ba,Sr,Ca)AlSiN.sub.3:Eu is used as the red emitting phosphor.

[0117] The red emitting phosphor converts electromagnetic radiation of the first wavelength range into electromagnetic radiation of a third wavelength range, such as the red spectral range. By combining phosphors emitting different colors, mixed light with a color locus in the white range, such as in the warm white range, can be generated from the electromagnetic radiation of the semiconductor chip 13 in the blue spectral range. By combining the semiconductor chip 13, which emits electromagnetic radiation of the first wavelength range, with the phosphor L1, which emits electromagnetic radiation of the second wavelength range, with the further phosphor LX, which emits electromagnetic radiation of a third wavelength range, electromagnetic radiation in the warm white range with a correlated color temperature CCT between 3000 K and 5000 K inclusive is generated.

[0118] FIG. 10 shows exemplarily two emission spectra of a phosphor L1 when excited with electromagnetic radiation of two primary wavelengths λ.sub.p of the semiconductor chip 13 according to an exemplary embodiment. The emission spectra are a curve in which the spectral intensity I or the spectral luminous flux per wavelength interval (“spectral intensity/spectral luminous flux”) of the electromagnetic radiation emitted from the phosphor L1 is plotted on the y-axis against the wavelength λ of the electromagnetic radiation emitted from the phosphor L1. If the primary wavelength λ.sub.p of the semiconductor chip is in the near ultraviolet spectral region, at about 408 nanometers, then the phosphor L1 described herein has an emission maximum in the green-yellow spectral region at about 515 nanometers with a dominant wavelength λ.sub.D of about 562 nanometers and a FWHM width of about 182 nanometers (solid line). Further, the primary wavelength λ.sub.p of the semiconductor chip may be in the blue spectral region, at about 448 nanometers. The phosphor L1 described here has an emission maximum in the green-yellow spectral region at about 525 nanometers with a dominant wavelength λ.sub.D of about 564 nanometers and a FWHM width of about 175 nanometers (dashed line).

[0119] FIG. 11 shows emission spectra of the phosphor L1 Sr.sub.7Li.sub.2Si.sub.5N.sub.4O.sub.12:Eu.sup.2+ in comparison with a conventional phosphor L2 with a comparable dominant wavelength λ.sub.D. Here, the intensity I, of the electromagnetic radiation emitted by the phosphors is plotted on the y-axis against the wavelength λ, of the electromagnetic radiation emitted by the phosphors. The conventional phosphor L2 has the general formula Y.sub.3(Al,Ga).sub.5O.sub.12:Ce. Here, the excitation wavelength of the phosphors is about 460 nanometers in the blue spectral region. The dominant wavelength λ.sub.D of the phosphor L1 is 562.9 nanometers. Compared with the conventional phosphor, the emission spectrum of the phosphor L1 comprises a shoulder in the red spectral region. The higher FWHM width and thus the increased proportion of reddish emission of the phosphor L1 compared to conventional phosphor L2 are shown in FIG. 11.

[0120] Furthermore, in FIG. 12 the color rendering index CRI is plotted against the primary wavelengths λ.sub.p of the semiconductor chips 13. For this purpose, the electromagnetic radiation with the emission spectrum of the phosphors L1, L2 and L3 in combination with L4 are each combined with different primary wavelengths λ.sub.p of different semiconductor chips 13. The phosphor L3 is described by the formula Lu.sub.3(Al,Ga).sub.5O.sub.12:Ce and the phosphor L4 is described by the formula CaAlSiN.sub.3:Eu. Four different semiconductor chips 13 with different primary wavelengths λ.sub.p of the semiconductor chip 13 in the blue spectral region were used. The color rendering indices CRI of the optoelectronic device 12 with the phosphor L1 shows values between 80 and 95, whereas the optoelectronic device 12 with the phosphor L2 and the combination of the phosphors L3 and L4 show lower color rendering indices CRI. L2 only shows color rendering indices CRI between 60 and 75.

[0121] Furthermore, FIG. 12 shows that it has only a minor effect on the color rendering index CRI of the optoelectronic device 12 with the phosphor L1 whether irradiation is performed with a primary wavelength λ.sub.p of the semiconductor chip 13 of about 415 nanometers or with a primary wavelength λ.sub.p of the semiconductor chip 13 of 450 nanometers. On the other hand, the different primary wavelengths λ.sub.p of the semiconductor chip 13 show stronger influence on the color rendering index CRI for the optoelectronic devices 12 with the phosphors L2 and L3 in combination with L4. When semiconductor chips 13 with shorter primary wavelengths λ.sub.p are used, the color rendering indices CRI for optoelectronic devices 12 with phosphor L2 and/or L3 in combination with L4 drop faster than when optoelectronic devices 12 with the phosphor L1 are used. For example, at a primary wavelength λ.sub.p of the semiconductor chip 13 of 450 nanometers to 430 nanometers, the color rendering index CRI for optoelectronic devices 12 with phosphors L3 combined with L4 is 94 and 78. In the case of the optoelectronic components 12 with the phosphor L1, the color rendering index CRI is 95 and 87 (see Table 4). As a result, semiconductor chips 13 emitting different primary wavelengths λ.sub.p of the electromagnetic radiation of the blue spectral range can be used for different optoelectronic devices 12 without much difference in the color rendering index CRI of the optoelectronic devices 12 with the phosphor L1 described here. Advantageously, this leads to a higher process yield and a reduction of production costs.

[0122] FIG. 13 shows a complete emission spectrum from 380 nanometers to 780 nanometers of the optoelectronic device 12 with the phosphor L1, L2 and the combination of L3 and L4. Here, the intensity I is plotted against the wavelength λ of the electromagnetic radiation emitted by the phosphors. It can be seen that the overall emission spectrum of the optoelectronic device 12 with the phosphor L1 exhibits a broader FWHM width than the comparable conventional optoelectronic devices 12 with phosphors L2 and L3 in combination with L4. Similarly, a distinct shoulder is visible in the red spectral region of the total emission spectrum of the optoelectronic device 12 with the phosphor L1.

[0123] Table 4 lists primary wavelengths λ.sub.p of the semiconductor chip 13, dominant wavelengths λ.sub.D, color rendering indices CRI, correlated color temperatures CCT, color loci CIE.sub.x and CIE.sub.Y, and red color rendering indices R9 for optoelectronic devices 12 with the phosphors L1, L2, and L3 in combination with L4. The comparable optoelectronic devices 12 with the phosphor L2 and the phosphors L3 and L4, respectively, show color loci close to those with the phosphor L1. Table 4 shows that the optoelectronic device 12 with the phosphor L1 exhibits a high correlated color temperature CCT, CCT≥9000 K at the same time as a high color rendering index CRI, CRI≥80, such as 85, such as 90, and a high red color rendering index R9, R9≥60, such as R9≥70, such as R9≥75.

TABLE-US-00004 Tabelle 4 Spectral data of various optoelectronic devices 12. λ.sub.P λ.sub.D CCT Solution [nm] [nm] CIE.sub.x CIE.sub.y [K] CRI R9 L1 415.5 442.5 0.286 0.294 9156 83 67 L2 415.5 442.5 0.277 0.293 10120 62 −46 L3 + L4 414.0 426.1 0.286 0.294 9172 70 50 L1 432.6 440.1 0.286 0.293 9201 87 72 L2 432.6 440.1 0.278 0.294 10033 63 −43 L3 + L4 434.0 439.8 0.286 0.293 9170 78 62 L1 438.7 444.6 0.283 0.290 9674 89 75 L2 438.7 444.6 0.274 0.289 10742 66 −39 L3 + L4 438.0 444.4 0.283 0.290 9620 83 70 L1 444.2 449.8 0.279 0.287 10305 94 80 L2 444.2 449.8 0.272 0.286 11522 71 −35 L3 + L4 444.0 449.6 0.279 0.287 10242 91 81 L1 450.8 455.4 0.270 0.276 12447 95 90 L2 450.8 455.4 0.284 0.276 13996 76 −24 L3 + L4 450.0 454.9 0.270 0.276 12515 94 95

[0124] The invention is not limited to the exemplary embodiments by the description based thereon. Rather, the invention encompasses any new feature as well as any combination of features, which particularly includes any combination of features in the patent claims, even if that feature or this combination itself is not explicitly stated in the patent claims or exemplary embodiments.

[0125] This patent application claims the priority of the German patent application DE 10 2019 104 008.6, the disclosure content of which is hereby incorporated by reference.

LIST OF REFERENCE SIGNS

[0126] 1 phosphor [0127] 2 strontium atom [0128] 3 lithium atom [0129] 4 silicon atom [0130] 5 europium atom [0131] 6 oxygen atom [0132] 7 nitrogen atom [0133] 8 Si(O,N).sub.4 tetrahedron [0134] 9 LiO.sub.4 tetrahedron [0135] 10 corner [0136] 11 channels [0137] 12 optoelectronic device [0138] 13 semiconductor chip [0139] 14 conversion element [0140] 15 encapsulant [0141] 16 carrier element [0142] 17 active zone [0143] 18 adhesive layer [0144] 19 radiation exit surface [0145] S1 process step [0146] S2 process step [0147] L1 phosphor 1 [0148] L2 phosphor 2 [0149] L3 phosphor 3 [0150] L4 phosphor 4 [0151] CCT correlated color temperature [0152] CRI color rendering index [0153] R9 red color rendering index [0154] CIE.sub.x color locus [0155] CIE.sub.Y color locus [0156] λ.sub.p primary wavelength [0157] λ.sub.D dominant wavelength