DE102012106940A1 - Manufacturing phosphor, comprises mixing starting materials comprising mixture of cationic component containing strontium, silicon, aluminum, europium and anionic component containing nitrogen and oxygen, and heating at reduced atmosphere - Google Patents

Abstract

Manufacturing a phosphor, comprises: (a) mixing the starting materials comprising mixture of a cationic component containing 10-60 mole% strontium, 40-90 mole% silicon, more than 0-40 mole% aluminum and more than 0-40 mole% europium, and an anionic component containing 40-100 mole% nitrogen and 0-60 mole% oxygen; and (b) heating the starting materials to a temperature of at least 1200[deg] C under reduced atmosphere. The reaction products comprising phosphor are obtained at least after the step (b). The phosphor absorbs at least a part of an electromagnetic primary radiation in UV or blue region. Manufacturing a phosphor, comprises: (a) mixing the starting materials comprising a mixture of cationic component containing 10-60 mole% strontium, 40-90 mole% silicon, more than 0-40 mole% aluminum and more than 0-40 mole% europium, and an anionic component containing 40-100 mole% nitrogen and 0-60 mole% oxygen; and (b) heating the starting materials to a temperature of at least 1200[deg] C under reduced atmosphere. The reaction products comprising the phosphor are obtained at least after the step (b). The phosphor absorbs at least a part of an electromagnetic primary radiation in the UV or the blue region and emits an electromagnetic secondary radiation in a wavelength region having an emission maximum of >= 620 nm. Independent claims are also included for: (1) phosphor obtained by the above mentioned method, comprising a composition comprising strontium, silicon, europium, and aluminum as the cationic fluorescent component and nitrogen and oxygen as the anionic fluorescent component; and (2) an optoelectronic component comprising a phosphor and which is provided for a beam path of the electromagnetic primary radiation, where the phosphor is arranged in the beam path.

Description

The present invention relates to a method for producing a phosphor, a phosphor and an optoelectronic component.

Radiation-emitting components, such as light-emitting diodes (LEDs), often contain phosphors in order to convert the radiation emitted by a radiation source into radiation with an altered, usually longer wavelength. In this case, the efficiency of the phosphor is generally dependent on its position of the absorption maximum with respect to the wavelength range of the electromagnetic primary radiation and / or on the position of its emission maximum. In particular, in the case of radiation-emitting components which emit warm white light, highly efficient phosphors are required which have an emission of electromagnetic radiation in the red range, for example in the range from 600 nm to 680 nm.

An object to be achieved is to provide a method for producing a phosphor, a phosphor and an optoelectronic component having improved efficiency.

This object is solved by the subject matters with the features of the independent claims. Advantageous embodiments and further developments of the objects are characterized in the dependent claims and will become apparent from the following description and the drawings.

• A) Mischen der Ausgangssubstanzen,
• – wobei die Mischung der Ausgangssubstanzen eine kationische Komponente und eine anionische Komponente aufweist,
• – wobei die kationische Komponente eine Kombination zumindest aus Strontium, Silizium, Aluminium und Europium umfasst,
• – wobei die anionische Komponente zumindest Stickstoff und Sauerstoff umfasst,
• – wobei ein Anteil an Strontium bezogen auf einen Gesamtanteil der kationischen Komponente größer oder gleich 10 mol-% und kleiner oder gleich 60 mol-% ist,
• – wobei ein Anteil an Silizium bezogen auf den Gesamtanteil der kationischen Komponente größer oder gleich 40 mol-% und kleiner oder gleich 90 mol-% ist,
• – wobei ein Anteil an Aluminium bezogen auf den Gesamtanteil der kationischen Komponente größer 0 mol-% und kleiner oder gleich 40 mol-% ist,
• – wobei ein Anteil an Europium bezogen auf den Anteil an Strontium größer 0 mol-% und kleiner oder gleich 40 mol-% ist,
• – wobei ein Anteil an Stickstoff bezogen auf den Gesamtanteil der anionischen Komponente größer oder gleich 40 mol-% und kleiner oder gleich 100 mol-% ist,
• – wobei ein Anteil an Sauerstoff bezogen auf den Gesamtanteil der anionischen Komponente größer oder gleich 0 mol-% und kleiner oder gleich 60 mol-% ist, und
• B) Erhitzen der Ausgangssubstanzen auf eine Temperatur von mindestens 1200 °C unter reduzierender Atmosphäre, wobei nach dem Verfahrensschritt B) zumindest ein oder mehrere Reaktionsprodukte erhalten werden, welche den Leuchtstoff umfassen, wobei zumindest der Leuchtstoff zumindest einen Teil einer elektromagnetischen Primärstrahlung im UV- oder blauen Bereich absorbiert und eine elektromagnetische Sekundärstrahlung in einem Wellenlängenbereich mit einem Emissionsmaximum von größer oder gleich 620 nm emittiert.

A method for producing a phosphor according to one embodiment comprises the method steps:

• A) mixing the starting substances,
• Wherein the mixture of starting substances has a cationic component and an anionic component,
• Wherein the cationic component comprises a combination of at least strontium, silicon, aluminum and europium,
• Wherein the anionic component comprises at least nitrogen and oxygen,
• Wherein a proportion of strontium based on a total proportion of the cationic component is greater than or equal to 10 mol% and less than or equal to 60 mol%,
• Wherein a proportion of silicon based on the total content of the cationic component is greater than or equal to 40 mol% and less than or equal to 90 mol%,
• Wherein a proportion of aluminum based on the total content of the cationic component is greater than 0 mol% and less than or equal to 40 mol%,
• Wherein a proportion of europium, based on the proportion of strontium, is greater than 0 mol% and less than or equal to 40 mol%,
• Wherein a proportion of nitrogen based on the total content of the anionic component is greater than or equal to 40 mol% and less than or equal to 100 mol%,
• - wherein a proportion of oxygen based on the total content of the anionic component is greater than or equal to 0 mol% and less than or equal to 60 mol%, and
• B) heating the starting materials to a temperature of at least 1200 ° C under a reducing atmosphere, wherein after step B) at least one or more reaction products are obtained which comprise the phosphor, wherein at least the phosphor at least part of an electromagnetic primary radiation in the UV or absorbed blue region and emits a secondary electromagnetic radiation in a wavelength range with an emission maximum of greater than or equal to 620 nm.

Here and below, the term "phosphor" denotes a substance which at least partially absorbs electromagnetic primary radiation and emits it as electromagnetic secondary radiation in a wavelength range which is at least partially different from the electromagnetic primary radiation. The phosphor can be referred to here and below as conversion material.

Electromagnetic primary radiation and / or electromagnetic secondary radiation may comprise one or more wavelengths and / or wavelength ranges in an infrared to ultraviolet wavelength range, in particular in a wavelength range between about 185 nm and 800 nm, preferably about 350 nm and 800 nm Be narrowband primary radiation and / or the spectrum of the electromagnetic secondary radiation, that is, that the electromagnetic primary radiation and / or the electromagnetic secondary radiation may have a monochrome or approximately monochrome wavelength range. The spectrum of the electromagnetic primary radiation and / or the spectrum of the electromagnetic secondary radiation may alternatively also be broadband, that is, that the electromagnetic primary radiation and / or the electromagnetic secondary radiation may have a mixed-color wavelength range, wherein the mixed-color wavelength range may each have a continuous spectrum or a plurality of discrete spectral components at different wavelengths.

According to one embodiment, at least the phosphor can convert electromagnetic primary radiation of one or more wavelengths or wavelength ranges from a UV or blue region. For example, the electromagnetic primary radiation can be generated by a light-emitting diode or a laser.

Here and below, color data in relation to emitting phosphors or electromagnetic radiation, for example electromagnetic primary and / or secondary radiation, designate the respective spectral range of the electromagnetic radiation, for example the electromagnetic primary radiation or electromagnetic secondary radiation.

According to a further embodiment, at least the phosphor converts electromagnetic primary radiation which lies within a wavelength range from 185 to 600 nm, preferably from 360 to 470 nm.

According to one embodiment, the phosphor converts electromagnetic primary radiation which serves to excite it.

The electromagnetic secondary radiation of the phosphor can have an emission maximum in the wavelength range from 600 nm to 680 nm, in particular from 620 nm to 660 nm, in particular 630 nm to 655 nm, for example 630 nm.

In particular, the secondary electromagnetic radiation has a maximum wavelength of greater than 630 nm or greater than 635 nm.

According to a further embodiment, the electromagnetic secondary radiation has an emission maximum of greater than 635 nm. In this case, the electromagnetic secondary radiation in comparison to the electromagnetic primary radiation have a wavelength range which is shifted to larger wavelengths.

According to one embodiment, in method step B at least one or more reaction products comprising the phosphor can be obtained. The phosphor can be extracted from the at least one reaction product.

As used herein, "cationic component" refers to elements of the periodic table, such as strontium, silicon, aluminum and europium, which are free as a cation (Sr ²⁺ , Si ^{+ 4} , Al ³⁺ , Eu ²⁺ ) or bound in a chemical compound , For example, at least one starting substance present. Being a cation in a chemical compound does not mean that the element of the periodic table is present as a free electrically charged atom or molecule (with at least one ionic charge) in the chemical compound. Rather, "cation" means the oxidation number and / or valence of the element of the periodic table. The oxidation number (also known as electrochemical valence) indicates how many elementary charges an atom would formally take up within a compound. It thus corresponds to the hypothetical ionic charge of an atom in a molecule or the actual charge of monatomic ions. The valence or valence of an atom is the maximum number of monovalent atoms that can be bound to an atom of a chemical element. Alternatively or additionally, the cationic component may comprise elements of the periodic system which are uncharged or present elementarily. Thus, for example, the cationic component may comprise metals, for example silicon, strontium, aluminum and / or europium as metal. In other words, the cationic component may comprise metals, for example silicon, strontium, aluminum and / or europium.

A component of the mixture of the starting substances is already referred to herein as a cationic component, if the cationic component incorporated in the at least one phosphor already behaves there like a cation (cationic phosphor component). For anionic component this applies accordingly.

A "combination of at least strontium, silicon, aluminum and europium" with respect to the cationic component in this context means that the cationic component of the mixture of the starting substances contains at least strontium, silicon, aluminum and europium, the sum of the proportions of strontium, Silicon, aluminum and europium is 100% or 100 mol%, if the cationic component contains no further elements, or less than 100% or 100 mol%, if in addition to strontium, silicon, aluminum and europium other elements form the cationic component ,

"Total content of the cationic component" in this context means at least the sum of the proportions of strontium, silicon, aluminum and europium, if the cationic component contains no further elements. If, in addition to strontium, silicon, aluminum and europium, other elements for the cationic component are included, then shares of these elements are added to the proportions of strontium, silicon, aluminum and europium and included in the share design.

In this context, "proportion of strontium" denotes the molar fraction in percent with the unit mol% of the strontium based on the total fraction of the cationic component.

"Percentage of silicon" or "proportion of aluminum" refers to the mole fraction in percent with the unit mol% of the respective element (silicon or aluminum) based on the total content of the cationic component.

"Percentage of europium" in this context refers to the mole fraction in percent with the unit mol% of europium based on the proportion of strontium.

"Anionic component" refers correspondingly to elements of the periodic table, such as nitrogen, chlorine and oxygen, which are used as anion, for example as oxide anion (O ^2- ), chloride anion (Cl ^- ), and / or sulfide anions (S ^2-). ) in a chemical compound, for example at least one starting substance. As an anion bound in a chemical compound does not mean that the element of the periodic table is present as a free electrically charged atom or molecule (with at least one ionic charge) in the chemical compound.

Rather, by anion is meant the oxidation number and / or valency of the element of the periodic table. The oxidation number (also called electrochemical valence) indicates how many elementary charges an atom would formally pick up within a compound, if all neighboring atoms with their common electron pairs were removed. It thus corresponds to the hypothetical ionic charge of an atom in a molecule or the actual charge of monatomic ions. The valence or valence of an atom is the maximum number of monovalent atoms that can be bound to an atom of a chemical element. Alternatively or additionally, the anionic component may comprise elements of the periodic table, which are uncharged or be present elementary, for example, as nitrogen (N _2), oxygen (O _2), chlorine (Cl ₂₎ and fluorine (F _2).

In this context, "proportion of nitrogen" or "proportion of oxygen" denotes the mole fraction in percent with the unit mol% of the nitrogen or oxygen, based on the total content of the anionic component.

Starting substances may be proportionately oxidized, ie, for example, Si ₃ N ₄ or AlN may contain appropriate amounts of surface area bound oxygen (O ₂ ). This is not considered in the proportion of nitrogen.

The "total content of the anionic component" here and hereinafter means the sum of at least the proportion of nitrogen and the proportion of oxygen, wherein the sum of the proportions of nitrogen and oxygen is 100% or 100 mol%, if the anionic component no further Contains elements, or less than 100% or 100 mol%, if in addition to nitrogen and oxygen, further elements for the anionic component are used.

In one embodiment, the mixture of starting materials may comprise a cationic component which is a combination of strontium, silicon, aluminum and europium.

According to a further embodiment, the anionic component of the mixture of the starting substances may consist of nitrogen and oxygen.

In accordance with at least one embodiment, at least one first starting substance has a first cationic component and a first anionic component, a second starting substance a second cationic component and a second anionic component, and an n-th starting substance an n-th cationic component and an n-th anionic component Component on. Here, n or n1 denotes an integer with n ≥ 3 or n1 ≥ 3. For example, the first cationic component is a cation and the first anionic component is an anion, which are bonded in the form of a salt. By mixing the starting substances, such as first, second, n-th starting substance, the cationic component of the mixture of the starting substances can be composed of the sum of the first, second, and nth cationic components and the anionic component of the mixture of the starting substances are formed from the sum of the first, second and nth anionic components.

According to at least one embodiment, the first cationic component, the second cationic component and / or the n1-th cationic component may be identical.

Accordingly, the first anionic component, the second anionic component and / or the nth anionic component may be identical.

In accordance with at least one embodiment, in method step A, the first, second and / or n-th starting substances are mixed next to one another. In this case, the first cationic component bound with the first anionic component as the first starting substance, the second cationic component bound with the second anionic component as the second starting substance and / or the n1-th cationic component bound with the n-th anionic component as n-th Starting substance present as a mixture. It is also possible that the number of different cationic and different anionic components differs, so that there are different starting materials with the same cationic or anionic component. The first, second and / or n1-th cationic component forms the cationic component and the first, second and / or n-th anionic component forms the anionic component of the mixture of the starting materials, wherein the respective anionic and cationic component chemically in the respective starting compounds are involved.

In accordance with at least one embodiment, the mixture of the starting substances comprises hydrides, carbonates, nitrides, oxides, for example hydrides, carbonates, nitrides, oxides of the rare earth metals, elements of the 3rd main group of the periodic table, elements of the 4th main group of the Periodic Table and / or alkaline earth metals and combinations thereof , Furthermore, chlorides, sulfates, phosphates, nitrates and combinations thereof can be used as a mixture of the starting materials. Alternatively or additionally, the cationic component of the mixture of the starting substances may comprise elements of the 2nd to 4th main group of the elements of the Periodic Table and / or rare earth metals. In particular, the cationic component may comprise strontium, silicon, aluminum and / or europium as the metal.

For synthesis, sufficient homogenization by mixing is required. In the mixing process, the conditions can be chosen so that sufficient energy is introduced into the mix, resulting in a milling of the starting materials. The resulting increased homogeneity and reactivity of the mixture can have a positive influence on the properties of the resulting phosphor.

According to one embodiment, the method step A can be carried out over a period of time which comprises 3 minutes to 24 hours, in particular between one hour and 8 hours, for example 3 hours. As a result, a homogeneous mixing can be ensured.

The starting substances can be weighed in stoichiometrically. Alternatively, the starting materials can be weighed non-stoichiometrically, wherein at least one starting substance can be weighed in excess in order to compensate for any evaporation losses during production. For example, starting materials comprising alkaline earth components may be weighed in excess.

Starting materials can be selected from a group comprising alkaline earth metals and their compounds, silicon and its compound, aluminum and its compound, and europium and its compound.

Here, alkaline earth metal compounds of alloy, hydrides, silicides, nitrides, halides, oxides, amides, amines, carbonates and alkaline earth metals and mixtures of this compound or metal to be selected. Strontium carbonate and / or strontium nitride are preferably used. Strontium carbonate is stable, readily available and cheap.

A silicon compound may be selected from silicon nitrides, alkaline earth silicides, silicon diimides, silicon hydrides, silicon oxide, as well as silicon or mixtures of this compound or silicon. Preference is given to using silicon nitrides and / or silicon oxides which are stable, readily available and inexpensive.

An aluminum compound can be selected from alloys, oxides, nitrides and aluminum and mixtures of this compound or aluminum. Preferably, alumina and / or aluminum nitride are used which are stable, readily available and inexpensive.

Compounds of europium may be selected from europium oxides, europium nitrides, europium halides, europium hydrides as well as europium or mixtures of this compound or europium. Preferably, europium oxide is used which is stable, readily available and inexpensive.

By deliberately changing the bulk density and / or by modifying the agglomeration of the mixture of the starting substance, the formation of secondary phases can be reduced. In addition, the particle size distribution, particle morphology and the yield of the resulting phosphor can be influenced. The techniques suitable here are, for example, residue-free sieving and granulation, if appropriate using suitable additives.

According to one embodiment, the mixture of the starting substances may have a proportion of strontium based on the total content of the cationic component between 10 mol% and 60 mol%. In particular, the proportion of strontium may be greater than or equal to 20 and less than or equal to 40 mol%, for example 30 mol%.

According to a further embodiment, the mixture of the starting substances may have a proportion of silicon based on the total content of the cationic component between 40 mol% and 90 mol%, in particular greater than or equal to 50 mol% and less than or equal to 70 mol%, for example 60 mol%.

According to one embodiment, the mixture of the starting substances may have a proportion of aluminum based on the total fraction of the cationic component greater than 0 mol% and less than or equal to 40 mol%, in particular between 1 and 25 mol%, for example 20 mol% or less or equal to 10 mol%, have.

According to a further embodiment, the mixture of the starting substances may contain a proportion of europium, based on the proportion of strontium greater than 0 mol% and less than or equal to 40 mol%, in particular greater than or equal to 0.5 mol% and less than or equal to 20 mol%. %, for example 1 mol% have.

Europium can be used as dopant and / or activator.

According to one embodiment, the cationic component may comprise further metals, for example cerium, gadolinium, and / or luthetium, as well as manganese, yttrium, gallium, lanthanum, scandium and / or combinations thereof. These elements of the periodic table can be used as a dopant, also called activator.

According to a further embodiment, the mixture of the starting substances may have a proportion of nitrogen, based on the total content of the anionic component, of greater than or equal to 40 mol%, in particular greater than or equal to 80 mol%, for example 95 mol%.

According to a further embodiment, the mixture of the starting substances may contain a proportion of oxygen based on the total content of the anionic component greater than or equal to 0 mol% and less than or equal to 60 mol%, in particular less than or equal to 20 mol%, for example 10 mol% , exhibit.

According to one embodiment, the proportion of oxygen is at least a few ppm. This can result from impurities in the starting substances, for example Eu ₂ O ₃ .

The ranges given here for the proportions of the anions or the proportions of the cations can be arbitrarily combined with one another according to the previous description, so that a mixture the starting substances can be prepared from any combination of the proportions of the individual anions or cations, even if this combination is not explicitly mentioned here.

The inventors have found that by mixing the starting materials with appropriate proportions of the elements in the cationic component and anionic component, at least one reaction product comprising the phosphor can be prepared. The mixture of the starting materials is heated to at least 1200 ° C under reducing atmosphere, wherein the phosphor emits secondary electromagnetic radiation in the red or deep red area. The phosphor has high stability, quantum efficiency, conversion efficiency, and low thermal quenching.

The phosphor may according to one embodiment be present as a minor phase or main phase of the reaction products or phase-pure. By "main phase" is meant in this context, a reaction product that has the largest proportion based on the total proportion of all reaction products. "Minor phase" refers to all reaction products that are not or are not a major phase.

In one embodiment, other phases that do not include the phosphor may or may not have luminescence.

According to a further embodiment, at least one flux or flux is additionally added in process step A). A flux may be used to enhance crystallinity and aid crystal growth of the phosphor. Melting flux can reduce the reaction temperature. Here, chlorides and fluorides of the alkaline earth metals used, such as strontium chloride, strontium fluoride, halides, such as ammonium chloride, ammonium fluoride, potassium fluoride, potassium chloride, magnesium fluoride, lithium fluoride, lithium chloride, carbonates, such as lithium carbonate and boron-containing compounds such as H ₃ BO ₃ , B ₂ O ₃ , Li ₂ B ₄ O ₇ , NaBO ₂ , Na ₂ B ₄ O ₇ . Furthermore, any combinations of two or more of the above-mentioned fluxes or fluxes come into question. The starting substances and optionally the melting or fluxing agents are homogenized, for example in a mortar mill, a ball mill, a turbulent mixer, a plowshare mixer or by other suitable methods.

The mixture of the starting substances can be heated once or several times in process step B according to one embodiment. The heating may take place in a crucible, for example of tungsten, molybdenum, corundum, alumina, graphite or boron nitride. In this case, the crucible may have a lining, for example made of molybdenum or a lining of sapphire. The heating may be carried out in a gas-tight oven under reducing atmosphere and / or inert gas such. B. in hydrogen, ammonia, argon, nitrogen or mixtures thereof. The atmosphere can be fluid or stationary. It may also be advantageous for the quality of the phosphor when elemental carbon is present in finely divided form in the furnace chamber. Alternatively, it is possible for carbon to be added directly to the mixture of starting compounds. Multiple heating of the phosphor with or without intermediate post-processing such. As grinding and / or sieving can further improve the crystallinity or the particle size distribution. Further advantages may be a lower defect density associated with improved optical properties of the phosphor and / or a higher stability of the phosphor, which are not obtained in conventional phosphors, which are not subjected to the repeated process step B, for the most part. Between the multiple heating, the phosphor may be treated or substances such as raw materials, flux, flux, other substances or a mixture of these substances may be added to the phosphor. The heated phosphor can still be ground. Conventional tools, such as a mortar mill, a fluidized bed mill or a ball mill can be used for the grinding of the phosphor. When grinding, the proportion of generated splinter grain should be kept as low as possible, as this may degrade the optical properties of the phosphor. In addition, a sieving can be carried out after grinding before repeating the method step B.

According to a further embodiment, the method step B) is carried out at least once for a duration of between 1 hour and 24 hours. Alternatively or additionally, process step B) is carried out under a reducing atmosphere or inert gas selected from the group consisting of hydrogen (H ₂ ), carbon monoxide (CO), nitrogen (N ₂ ), argon, ammonia (NH ₃ ) and combinations it includes.

Occasionally, according to one embodiment, short annealing steps may be performed in air at low T <600 ° C.

According to a further embodiment, the method step B can be performed twice or more times. For example, method step B can be carried out one to three times.

According to a further embodiment, process step B) is carried out at a temperature of greater than or equal to 1200 ° C., especially at 1200 ° C. to 2000 ° C., preferably at 1400 ° C. to 2000 ° C., more preferably at 1400 ° C. to 1800 ° C., for example, carried out at 1600 ° C.

The homogenized starting mixture, which can be obtained in process step A), can be calcined in process step B) in a furnace, for example a tube furnace, a chamber furnace or a push through furnace, for several hours under reducing atmosphere or inert gas. The annealed material can then be ground, for example in a mortar mill, ball mill, fluidized bed mill or other types of mill.

According to a further embodiment, an additional method step C) can be carried out after method step B). This is especially the case when the phosphor has not been obtained in a pure state.

According to one embodiment, process step C) comprises the process step: C) isolation of the phosphor by chemical aftertreatment, for example acid washing in HCl or another acid.

The ground powder from process step B) or C) can be subjected to further fractionation and classification steps, such as screening, flotation or sedimentation.

In process step C), the phosphor can be washed in water or in aqueous acids and / or bases such as hydrochloric acid, nitric acid, hydrofluoric acid, sulfuric acid, organic acids, sodium hydroxide or a mixture of these. As a result, secondary phases, glass phases or other impurities can be removed and an improvement in the optical properties of the phosphor can be achieved. It is also possible to initiate classifying specifically smaller phosphor particles and to optimize the particle size distribution for the application.

There is further provided a phosphor obtainable by a process for producing a phosphor, the phosphor having a composition comprising strontium, silicon, europium and aluminum as the cationic phosphor component and nitrogen and oxygen as the anionic phosphor component, the phosphor having at least one Absorbs part of an electromagnetic primary radiation in the UV or blue region and emits an electromagnetic secondary radiation in a wavelength range with an emission maximum of greater than or equal to 620 nm.

In this case, all the embodiments and definitions previously described in the description of the general part, which have been described in the method for producing a phosphor apply to the phosphor.

"Cationic phosphor component" here and hereinafter means that the phosphor comprises or consists of at least strontium, silicon, aluminum and europium as cations, the sum of the proportions of strontium, silicon, aluminum and europium being 100% or 100 mol%, if the cationic phosphor component no further Contains elements, or less than 100% or 100 mol%, if in addition to strontium, silicon, aluminum and europium also other elements for the cationic phosphor component are used. "As a cation" does not mean that the element of the periodic table exists as a free electrically charged atom or molecule (with at least one ionic charge) in the chemical compound. Rather, by "as cation" is meant a positive oxidation number and / or valence of the element of the periodic table. The oxidation number (also called electrochemical valence) indicates how many elementary charges an atom would formally pick up within a compound, if all neighboring atoms with their common electron pairs were removed. It thus corresponds to the hypothetical ionic charge of an atom in a molecule or the actual charge of monatomic ions. The valence or valence of an atom is the maximum number of monovalent atoms that can be bound to an atom of a chemical element.

"Anionic phosphor component" means here and below that the phosphor comprises or consists of at least oxygen and nitrogen as anions, the sum of the proportions oxygen and nitrogen being 100% or 100 mol%, if the anionic phosphor component contains no further elements, or less than 100% or 100 mol%, if in addition to oxygen and nitrogen and other elements for the anionic phosphor component are used. "As an anion" does not mean that the element of the periodic table exists as a free electrically charged atom or molecule (with at least one ionic charge) in the chemical compound. Rather, by anion or with the ionic charge of the anion is meant an element of the periodic table with a negative oxidation number and / or valency. The oxidation number (also called electrochemical valence) indicates how many elementary charges an atom would formally pick up within a compound, if all neighboring atoms with their common electron pairs were removed. It thus corresponds to the hypothetical ionic charge of an atom in a molecule or the actual charge of monatomic ions. The valence or valence of an atom is the maximum number of monovalent atoms that can be bound to an atom of a chemical element.

According to a further embodiment, the phosphor emits an electromagnetic secondary radiation in a wavelength range with an emission maximum of 600 nm to 680 nm, preferably 620 nm to 660 nm, particularly preferably 635 nm to 650 nm, for example 648 nm.

According to a further embodiment, the phosphor has an emission maximum at 650 +/- 10 nm, for example 648 nm, 652 nm, 653 nm, 655 nm and / or 658 nm.

According to a further embodiment, the phosphor has an emission maximum at 640 +/- 10 nm.

According to a further embodiment, the following empirical formulas for phosphor free phases are proposed for the phosphor but could not yet be assigned with certainty:
(Sr _1-y Eu _y ) Si _4-x Al _x O _x N _6-x with 1 ≦ x ≦ 2 and 0 ≦ y ≦ 1
(Sr _1-y Eu _y ) ₄ Si _13-x Al _x O _x N _20-x with 3 ≤ x ≤ 7 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₄ Si _10-x Al _x O _x N _16-x with 2 ≤ x ≤ 5 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₅ Si _14-x Al _x O _x N _22-x with 3 ≤ x ≤ 6 and 0 ≤ yv 1
(Sr _1-y Eu _y ) ₄ Si _11-x Al _x O _{2 + x} N _16-x with 2 ≤ x ≤ 5 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₈ Si _22-x Al _x O _{1 + x} N _28-x with 4 ≤ x ≤ 9 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₃ Si _9-x Al _x O _{3 + x} N _12-x with 1 ≤ x ≤ 3 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₅ Si _13-x Al _x O _{1 + x} N _20-x with 2 ≤ x ≤ 5 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₃ Si _8-x Al _x O _{1 + x} N _12-x with 2 ≤ x ≤ 4 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₂ Si _4-x Al _x O _{1 + x} N _6-x with 1 ≤ x ≤ 2 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₅ Si _12-x Al _x O _{2 + x} N _18-x with 2 ≤ x ≤ 4 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₄ Si _9-x Al _x O _{1 + x} N _14-x with 2 ≤ x ≤ 4 and 0 ≤ y ≤ 1
(Sr _1-y Eu _y ) ₄ Si _10-x Al _{1 + x} O _x N _17-x with 2 ≤ x ≤ 6 and 0 ≤ y ≤ 1
x and / or y values in the above structural formulas of the phosphor may according to one embodiment be non-integer values.

The phosphor does not necessarily have to have mathematically exact composition according to the above formulas. Rather, they may, for example, have one or more additional dopants, as well as additional constituents. For the sake of simplicity, however, the above formulas contain only the essential components.

Possibly, the phosphor also has a different empirical formula that could not yet be identified or assigned.

According to a further embodiment, the structures and / or the stoichiometric composition for the phosphor pure phases can be determined in more detail for example by means of elemental analysis, X-ray diffraction (XRD, X-ray diffraction), transmission electron microscopy (TEM) or single crystal analysis.

According to one embodiment, the phosphor may be present as ceramic or embedded in glass.

Furthermore, an optoelectronic component is specified which comprises the phosphor whose production has been described above, the optoelectronic component providing a beam path of the electromagnetic primary radiation, the phosphor being arranged in the beam path.

In this case, all embodiments previously described in the description of the general part and definition of the method for producing a phosphor and the phosphor apply to the optoelectronic component.

It should be noted at this point that the term "component" here not only finished components, such as light emitting diodes (LEDs) or laser diodes are to be understood, but also substrates and / or semiconductor layers, so for example, already a composite of a copper layer and a Semiconductor layer represent a component and can form part of a parent second component in which, for example, additional electrical connections are available. The optoelectronic component according to the invention can be, for example, a thin-film semiconductor chip, in particular a thin-film light-emitting diode chip.

According to one embodiment, the optoelectronic component may comprise a layer sequence. In this context, "layer sequence" is understood as meaning a layer sequence comprising more than one layer, for example a sequence of a p-doped and an n-doped semiconductor layer, the layers being arranged one above the other. The layer sequence can emit the electromagnetic primary radiation.

According to one embodiment, the layer sequence may be a semiconductor layer sequence, wherein the semiconductor materials occurring in the semiconductor layer sequence are not limited, as long as they have at least partial electroluminescence. For example, compounds of the elements selected from indium, gallium, aluminum, nitrogen, phosphorus, arsenic, oxygen, silicon, carbon, and combinations thereof are used. However, other elements and additions may be used. The active region layer sequence may be based, for example, on nitride compound semiconductor materials. "Based on nitride compound semiconductor material" in the present context means that the semiconductor layer sequence or at least a part thereof, a nitride compound semiconductor material, preferably comprises or consists of Al _n Ga _m In _{1 nm} where 0 ≤ n ≤ 1, 0 ≤ m ≤ 1 and n + m ≤ 1. However, this material does not necessarily have to have a mathematically exact composition according to the above formula. Rather, it may, for example, have one or more dopants and additional constituents. For the sake of simplicity, however, the above formula contains only the essential constituents of the crystal lattice (Al, Ga, In, N), even if these can be partially replaced and / or supplemented by small amounts of further substances.

The semiconductor layer sequence can have as active region, for example, a conventional pn junction, a double heterostructure, a single quantum well structure (SQW structure) or a multiple quantum well structure (MQW structure). The semiconductor layer sequence can comprise, in addition to the active region, further functional layers and functional regions, for example p- or n-doped charge carrier transport layers, ie electron or hole transport layers, p- or n-doped confinement or cladding layers, buffer layers and / or electrodes and combinations it. Such structures relating to the active region or the further functional layers and regions are known to the person skilled in the art, in particular with regard to structure, function and structure, and are therefore not explained in more detail here.

Alternatively, it is possible to select an organic light-emitting diode (OLED) as the optoelectronic component, wherein, for example, the electromagnetic primary radiation emitted by the OLED is converted into an electromagnetic secondary radiation by a conversion material or phosphor located in the beam path of the electromagnetic primary radiation.

According to a further embodiment, during operation of the optoelectronic component, the electromagnetic primary radiation is emitted by the layer sequence with an active region and impinges on the phosphor which is arranged in the beam path of the electromagnetic primary radiation and is suitable for absorbing the electromagnetic primary radiation at least partially and as secondary electromagnetic radiation with an at least partially different from the electromagnetic primary radiation wavelength range to emit.

According to one embodiment, the optoelectronic component may have, in addition to the phosphor, a further phosphor which emits a further electromagnetic secondary radiation.

According to a further embodiment, the entire secondary electromagnetic radiation can be emitted from an electromagnetic secondary radiation which is emitted by the phosphor, for example the first phosphor, and at least one further secondary electromagnetic radiation which is emitted by the latter another phosphor, for example, called second phosphor, is emitted, put together. The further electromagnetic secondary radiation may have a wavelength in the range 490 nm to 680 nm, z. B. 560 nm. The electromagnetic secondary radiation may have a maximum wavelength which is greater than or equal to 600 nm, preferably greater than or equal to 620 nm, for example 650 nm. The phosphor thus emits in the red spectral range of the electromagnetic radiation and the further phosphor in the yellow or green spectral range of the electromagnetic radiation.

The optoelectronic component has, according to a further embodiment, a total emission, which is composed of electromagnetic primary radiation and the total electromagnetic secondary radiation.

In particular, the total emission can be perceived as white light by an external observer during operation of the optoelectronic component.

Alternatively, it is possible that the phosphor, but no further phosphor is present in the optoelectronic component. As a result, in particular when the optoelectronic component is in operation, the total emission perceived by an external observer can be perceived as red light. In this case, the electromagnetic primary radiation can be at least partially absorbed by the phosphor and converted into an electromagnetic secondary radiation having a wavelength of greater than or equal to 200 nm.

According to a further embodiment, at least the phosphor can be embedded in a matrix material. The embedding of the phosphor in the matrix material may be distributed or embedded homogeneously or with a concentration gradient. In particular, polymers or ceramic materials or glass are suitable as the matrix material. For example, the matrix material may comprise or be an epoxy resin, polymethyl methacrylate (PMMA), polystyrene, glass, ceramics such as YAG or Al ₂ O ₃ , polycarbonate, polyacrylate, polyurethane or a silicone resin such as polysiloxane or mixtures thereof.

According to a further embodiment, the phosphor can be embedded in a matrix material and shaped as a potting compound, layer or foil. The potting may for example be cohesively or a potting compound with a layer sequence connected to an active area. The potting compound may be, for example, polymer material. In particular, it may be epoxy or silicone, a methyl-substituted silicone, for example poly (dimethylsiloxane) and / or polymethylvinylsiloxane, a cyclohexyl-substituted silicone, for example poly (dicyclohexyl) siloxane or a combination thereof.

Further, the matrix material may additionally comprise a filler such as a metal oxide such as titanium dioxide, silica, zirconia, zinc oxide, alumina, and / or glass particles.

According to one embodiment, the phosphor can be formed as particles or ceramic platelets and at least partially scatter the electromagnetic primary radiation. At the same time, the phosphor can be designed as a luminous center which partially absorbs radiation of the primary electromagnetic radiation and emits secondary electromagnetic radiation, and as a scattering center for the primary electromagnetic radiation. The scattering properties of the phosphor can lead to improved radiation extraction from the device. The scattering effect can, for example, also lead to an increase in the absorption probability of primary radiation in the phosphor, which may necessitate a smaller layer thickness of the layer containing the phosphor.

According to a further embodiment, the optoelectronic component can have an encapsulation enclosing the layer sequence with the active region, wherein the phosphor can be arranged in the beam path of the electromagnetic primary radiation inside or outside the encapsulation. The encapsulation can be embodied in each case as thin-layer encapsulation.

In one embodiment, the phosphor is in direct contact with the radiation source. Thus, the conversion of the electromagnetic primary radiation into the electromagnetic secondary radiation at least partially close to the radiation source, for example at a distance phosphor and radiation source of less than or equal to 200 microns, preferably less than or equal to 50 microns done (so-called "chip level conversion").

In one embodiment, the phosphor is spaced from the radiation source. Thus, at least in part, the conversion of the electromagnetic primary radiation into the electromagnetic Secondary radiation at a great distance from the radiation source. For example, at a distance between the phosphor and the radiation source of greater than or equal to 200 microns, preferably greater than or equal to 750 microns, more preferably greater than or equal to 900 microns (so-called "Remote Phosphor Conversion").

Further advantages and advantageous embodiments and further developments of the article according to the invention will become apparent from the following in the embodiments described in more detail in connection with the figures.

The figures show:

1a schematically a ternary phase diagram of the mole fraction ratio of the cationic component of the mixture of the starting materials,

1b schematically a ternary phase diagram of the mole fraction ratio of the cationic component of the mixture of the starting substances,

2a Emission spectra of embodiments and a comparative example,

2 B an emission spectrum of an embodiment,

3 Emission spectra of an embodiment,

4a an X-ray powder diffractogram of a comparative example,

4b an X-ray powder diffractogram of a comparative example,

4c an X-ray powder diffractogram of an embodiment,

5 the schematic side view of an optoelectronic device.

• 1a-1: Si:Al:Sr = 0,949:0,001:0,050,
• 1a-2: Si:Al:Sr = 0,374:0,001:0,625,
• 1a-3: Si:Al:Sr = 0,225:0,350:0,425, und
• 1a-4: Si:Al:Sr = 0,600:0,350:0,050.

The 1a shows a ternary phase diagram of the mole fraction ratio of the cationic component in the mixture of the starting materials comprising silicon (Si), strontium (Sr) and aluminum (Al). Europium (Eu) as doping is not shown here. The anionic component of the mixture of starting substances comprising nitrogen and oxygen can be represented as the fourth dimension in the phase diagram. The equilateral triangle represents the concentration or molar fracture plane of the cationic components in the mixture of the starting materials. The sides of the equilateral triangle denote here the respective mole fractions of silicon (x _Si ), strontium (x _Sr ) and aluminum (x _Al ). The sum of the individual mole fractions of the cationic component results in the sum of 1 or 100% or 100 mol%. The formula is: _Al x + x + _Sr x _Si = 1. In the ternary phase diagram of the light gray area denotes a molar composition of the mixture of the starting materials whose reaction product or reaction products comprising the phosphor. The light gray area is shown by a quadrangular area with vertices 1a-1, 1a-2, 1a-3 and 1a-4 in the ternary phase diagram. The definition of oxygen and nitrogen is the fourth dimension of the ternary phase diagram. The vertices of the quadrilateral face show the molar fraction ratio of the cationic component as follows:

• 1a-1: Si: Al: Sr = 0.949: 0.001: 0.050,
• 1a-2: Si: Al: Sr = 0.374: 0.001: 0.625,
• 1a-3: Si: Al: Sr = 0.225: 0.350: 0.425, and
• 1a-4: Si: Al: Sr = 0.600: 0.350: 0.050.

The ellipsoidal dark gray region in the ternary phase diagram shows the mole fraction ratio of the cationic component of the mixture of starting substances which emit in a wavelength range of 600 nm to 680 nm, preferably 620 to 660 nm, particularly preferably 635 to 655 nm, for example 650 nm.

• A: Si:Al:Sr = 0,72:0:0,28,
• B: Si:Al:Sr = 0,60:0,10:0,30,
• C: Si:Al:Sr = 0,50:0,20:0,30, und
• D: Si:Al:Sr = 0,55:0,05:0,4.

1b shows how 1a the ternary phase diagram of the molar fraction ratio of the cationic component (here Sr, Al, Si) in the starting material mixture used. In contrast to 1a are in 1b Embodiments B, C and D indicated. A is a comparative example of a conventional red-emitting phosphor. In this case, the ratio of Sr, Si and Al is shown for Sr ₂ Si ₅ N ₈ : Eu. The following applies:

• A: Si: Al: Sr = 0.72: 0: 0.28,
• B: Si: Al: Sr = 0.60: 0.10: 0.30,
• C: Si: Al: Sr = 0.50: 0.20: 0.30, and
• D: Si: Al: Sr = 0.55: 0.05: 0.4.

The following Table 1 gives the proportions of the starting materials for the embodiments B, C and D and for the comparative example A in g, which were mixed together. Furthermore, Table 1 shows further embodiments F, G, H and I, and a further comparative example E. Table 1 λ _max FWHM Mass of the starting substances in g nm nm SrCO ₃ SiO ₂ Si ₃ N ₄ Al ₂ O ₃ AlN Sr ₃ N ₂ Eu ₂ O ₃ A 625 90 0 0 325.4 0 0 255.1 19:59 B 646 127 16.3 27.5 294.4 6.2 42.1 305.3 21.1 C 648 116 0 0 114.5 0 242.8 332.5 24.2 D 653 125 110.3 68.2 185.7 11.6 32.6 308.0 28.2 e 628 94 0 0 293.2 0 0 389.7 28.6 F 658 143 0 0 56.7 0 293.8 325.7 24.7 G 655 126 62.6 35.4 167.1 14.4 72.6 345.9 28.7 H 653 125 110.3 68.2 185.7 11.6 32.6 308 28.2 I 652 158 276.6 65.7 73.2 16.9 22.1 304.9 41

In this case, λ _max in nm means the emission maximum of the phosphor and / or the total emission maximum of the reaction products. FWHW in nm stands for the half-width of the emission spectrum of the phosphor and / or the total emission spectrum of the reaction products. For example, it can be seen from Table 1 that the mixture of the starting materials of Example B 16.3 g SrCO ₃ , 27.5 g SiO ₂ , 294.4 g Si ₃ N ₄ , 6.2 g Al ₂ O ₃ , 42.1 g AlN, 305.3 g Sr ₃ N ₂ and 21.1 g of Eu ₂ O ₃ . This mixture of the starting compounds is heated to at least 1200 ° C under a reducing atmosphere to form at least one reaction product comprising the phosphor. The phosphor, or the reaction products of the embodiment B have an emission spectrum with a half-width of 127 nm and an emission maximum of 646 nm. In this case, the mixture of the starting materials of the embodiments B, C, D, F, G, H and I, in comparison to the comparative examples A and E, which comprise the conventional phosphor Sr ₂ Si ₅ N ₅ : Eu, a secondary radiation in a wavelength range , which is shifted to a higher wavelength.

2a shows the ones in the 1b shown embodiments B to D and the comparative example A associated emission spectra, wherein the intensity I in percent as a function of the wavelength λ in nm is shown. It can be seen from the emission spectra that the embodiments B, C and D have a higher emission maximum compared to Comparative Example A, which comprises the phosphor Sr ₂ Si ₅ N ₈ : Eu with an Eu content of 4 mol%. Thus, Comparative Example A shows an emission maximum of 625 nm, whereas embodiments B have an emission maximum of 646 nm, C an emission maximum of 648 nm and D an emission maximum of 653 nm.

The 2 B shows an emission spectrum with an intensity I in percent as a function of the wavelength λ in nm of the phosphor, which was isolated after process step C by an acid wash. It was with an electromagnetic primary radiation having a wavelength of 460 nm, excited. The emission maximum is 648 +/- 2 nm. Thus, the phosphor shows in comparison to conventional red-emitting phosphors shifted to larger wavelength electromagnetic secondary radiation.

3 shows examples of emission spectra 3-1 and 3-2 with a relative intensity I in percent as a function of the wavelength λ in nm of the phosphor, which was isolated after process step C. The proportion of europium based on the proportion of strontium in the mixture of the starting substances is in the embodiment 3-1 2 mol% and at 3-2 4 mol%. The variation of the proportion of europium in the mixture of the starting substances has an influence on the emission spectra. As the proportion of europium increases from 2 mol% to 4 mol%, the emission maximum of 634 +/- 2 nm shifts to 641 +/- 2 nm in the exemplary embodiment.

4a shows a calculated X-ray powder diffractogram with the intensity I in a. U. (arbitrary unit) as a function of 2θ in ° of the comparative example Sr ₂ Si ₅ N ₈ . The angle 2θ designates here and below the angle between radiation source, sample and detector. 4b shows an experimentally determined X-ray powder diffractogram of Sr ₂ Si ₅ N ₈ : Eu ²⁺ with the intensity I in a. U. as a function of 2θ in ° of this comparative example. 4c shows an experimentally determined X-ray powder diffractogram with the intensity I in a. U. as a function of 2θ in ° of the isolated Eu ²⁺ -doped phosphor. The reflection pattern of the phosphor differs from the reflection pattern of the comparative example inter alia in that at high angles of 2θ = 35 to 37 °, only two reflections are observed. The comparative example, in contrast, has three characteristic reflections in this 2θ region. Furthermore, characteristic differences in the range of 2θ from 27 to 32 ° and over the entire 2θ range can be observed. Thus, the structure of the phosphor differs significantly from the structure of the comparative example.

5 shows a schematic side view of an optoelectronic component in the embodiment of a light emitting diode (LED). The optoelectronic component has a layer sequence 1 with an active area (not explicitly shown), a first electrical connection 2 , a second electrical connection 3 , a bonding wire 4 , a casting 5 , a housing wall 7 , a housing 8th , a recess 9 , a fluorescent 6 , and a matrix material 10 on. The layer sequence 1 with an active area containing the phosphor 6 is within the optoelectronic device, the encapsulation 5 and / or the recess 9 arranged. The first and second electrical connection 2 . 3 are under the layer sequence 1 arranged with an active area. An indirectly and / or directly direct electrical and / or mechanical contact, the layer sequence 1 with an active area and the bonding wire 4 and the layer sequence 1 with an active area with the first and / or the second electrical connection 2, 3.

Furthermore, the layer sequence 1 be arranged with an active area on a support (not shown here). A carrier can be, for example, a printed circuit board (PCB), a ceramic substrate, a printed circuit board or a metal plate, for. B. aluminum plate act.

Alternatively, a carrierless arrangement of the layer sequence 1 possible with so-called thin-film chips.

The active region is suitable for emitting electromagnetic primary radiation in a direction of emission. The layer sequence 1 for example, with an active region may be based on nitride compound semiconductor material. Nitride compound semiconductor material emits in particular electromagnetic primary radiation in the blue and / or ultraviolet spectral range. In particular, InGaN may be used as a nitride compound semiconductor material which has an electromagnetic primary radiation having a wavelength of 460 nm.

In the beam path of the electromagnetic primary radiation is the phosphor 6 , which as shown here is in particulate form and in a matrix material 10 embedded, arranged. The matrix material 10 is for example polymer or ceramic material. Here is the phosphor 6 directly in direct mechanical and / or electrical contact on the layer sequence 1 arranged with an active area.

Alternatively, other layers and materials, such as potting, may be interposed between the phosphor 6 and the layer sequence 1 be arranged (not shown here).

Alternatively, the phosphor can 6 indirectly or directly on the housing wall 7 a housing 8th be arranged (not shown here).

Alternatively, it is possible that the phosphor 6 is embedded in a potting compound (not shown here) and together with the matrix material 10 as casting 5 is formed.

The phosphor 6 at least partially converts the electromagnetic primary radiation into an electromagnetic secondary radiation. For example, the electromagnetic primary radiation is emitted in the blue spectral range of the electromagnetic radiation, wherein at least part of this electromagnetic primary radiation from the phosphor 6 can be converted into an electromagnetic secondary radiation in the red spectral range of the electromagnetic radiation. Alternatively or additionally, further phosphors may be present which, for example, have a further electromagnetic secondary radiation in the green spectral range. The total radiation emerging from the optoelectronic component is a superimposition of blue emitting primary radiation and red and green emitting secondary radiation, the total emission visible to the external observer being white light.

The invention is not limited by the description with reference to the embodiments. Rather, the invention encompasses any novel feature as well as any combination of features, including in particular any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the claims or exemplary embodiments.

Claims (15)

 Process for the preparation of a phosphor comprising the process steps: A) mixing the starting substances, Wherein the mixture of starting substances has a cationic component and an anionic component, Wherein the cationic component comprises a combination of at least strontium, silicon, aluminum and europium, Wherein the anionic component comprises at least nitrogen and oxygen, Wherein a proportion of strontium based on a total proportion of the cationic component is greater than or equal to 10 mol% and less than or equal to 60 mol%, Wherein a proportion of silicon based on the total content of the cationic component is greater than or equal to 40 mol% and less than or equal to 90 mol%, Wherein a proportion of aluminum based on the total content of the cationic component is greater than 0 mol% and less than or equal to 40 mol%, Wherein a proportion of europium, based on the proportion of strontium, is greater than 0 mol% and less than or equal to 40 mol%, Wherein a proportion of nitrogen based on the total content of the anionic component is greater than or equal to 40 mol% and less than or equal to 100 mol%, - wherein a proportion of oxygen based on the total content of the anionic component is greater than or equal to 0 mol% and less than or equal to 60 mol%, and B) heating the starting materials to a temperature of at least 1200 ° C under a reducing atmosphere, wherein after the method step B at least one or more reaction products are obtained, which comprise the phosphor (6), wherein at least the phosphor (6) absorbs at least part of an electromagnetic primary radiation in the UV or blue region and an electromagnetic secondary radiation in a wavelength range with a Emission maximum of greater than or equal to 620 nm emitted.  The method of claim 1, wherein the mixture of the starting materials has a content of strontium based on the total content of the cationic component between 10 mol% and 60 mol%.  Method according to one of the preceding claims, wherein the mixture of the starting materials has a proportion of silicon based on the total content of the cationic component between 40 mol% and 90 mol%.  Method according to one of the preceding claims, wherein the mixture of the starting materials has a proportion of aluminum based on the total content of the cationic component greater than 0 mol% and less than or equal to 40 mol%.  Method according to one of the preceding claims, wherein the mixture of the starting materials, a proportion of nitrogen based on the total content of the anionic component greater than or equal to 40 mol%.  A process according to any one of the preceding claims wherein the mixture of starting materials comprises hydrides, carbonates, nitrides, oxides, metals and combinations thereof.  Method according to one of the preceding claims, wherein in step A additionally at least one flux is added. Method according to one of the preceding claims, wherein the method step B is carried out at least once for a duration between one hour and 24 hours and / or where inert gas or reducing atmosphere is used, wherein the reducing atmosphere is selected from a group comprising water vapor (H ₂ O), carbon monoxide (CO), nitrogen (N ₂ ), argon, ammonia (NH ₃ ), forming gas and combinations thereof.  Method according to one of the preceding claims, wherein the method step B is performed twice or more times.  Method according to one of the preceding claims, that after method step B has an additional method step C: C) Isolation of the phosphor by chemical aftertreatment. A phosphor obtainable by a process for producing a phosphor according to any one of claims 1 to 10, - wherein the phosphor has a composition comprising strontium, silicon, europium and aluminum as cationic phosphor component and nitrogen and oxygen as anionic phosphor component, - wherein the phosphor ( 6 ) absorbs at least part of an electromagnetic primary radiation in the UV or blue region and emits an electromagnetic secondary radiation in a wavelength range with an emission maximum of greater than or equal to 620 nm.  The phosphor according to claim 11, wherein the primary electromagnetic radiation is in a wavelength range of 185 to 600 nm.  The phosphor of claim 11, wherein the secondary electromagnetic radiation has an emission maximum of greater than 630 nm. The phosphor according to claim 11, wherein the phosphor ( 6 ) has an emission maximum at 640 ± 10 nm. Optoelectronic component comprising a phosphor according to any one of claims 11 to 14 or a phosphor which can be produced from the method according to one of claims 1 to 10, wherein the optoelectronic component provides a beam path of the electromagnetic primary radiation, wherein the phosphor ( 6 ) is arranged in the beam path.

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