DE102019121348A1 - LUMINOUS, PROCESS FOR THE MANUFACTURING OF A LUMINOUS AND OPTOELECTRONIC COMPONENT - Google Patents

Abstract

A phosphor with the general formula EA (3-x) RExAl (2 + x) Si (3-x) O12: A is specified, where EA is selected from the group of divalent cations, RE is selected from rare earth metal ions, A is selected is made up of activator ions, and 0 <x <2. A method for producing a phosphor and an optoelectronic component containing a phosphor are also specified.

Description

A phosphor, a method for producing a phosphor and an optoelectronic component are specified.

One problem to be solved is to specify a phosphor with improved properties. In addition, a method for producing a phosphor with improved properties and an optoelectronic component with a phosphor with improved properties are to be specified.

These objects are achieved by a phosphor, a method and an optoelectronic component with the features of the independent claims. Advantageous embodiments of the phosphor, the method and the component are the subject matter of the respective dependent claims.

angegeben. Dabei ist EA ausgewählt aus der Gruppe der zweiwertigen Kationen und RE ausgewählt aus Seltenerdmetallionen. Weiterhin ist A ausgewählt aus Aktivatorionen, und es gilt 0 < x < 2.It becomes a phosphor with the general formula $${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A.}$$

specified. EA is selected from the group of divalent cations and RE is selected from rare earth metal ions. Furthermore, A is selected from activator ions, and 0 <x <2 applies.

The term “phosphor” is understood here and below to mean a wavelength conversion substance, that is to say a material that is designed to absorb and emit electromagnetic radiation. In particular, the phosphor absorbs radiation which has a different wavelength maximum than the emission maximum of the phosphor. For example, the phosphor absorbs radiation with a wavelength maximum at smaller wavelengths than the emission maximum and thus emits radiation with an emission maximum shifted in the direction of red. Pure scattering or pure absorption are not understood here to be wavelength-converting.

Here and below, phosphors are described with empirical formulas. It is possible with the given formulas that the phosphor has further elements, for example in the form of impurities, these impurities taken together with a proportion of at most 1 per thousand, preferably at most 100 ppm (parts per million), particularly preferably at most 10 ppm in the phosphor available.

The phosphor is made up of elements that are present in the phosphor as ions, i.e. anions or cations. Here and below, the constituents of the phosphor, in particular EA, RE and A, are referred to both as elements and as ions or cations or anions. For the sake of clarity, the specification of specific elements does not necessarily include the specification of the load. In particular, EA, RE, Al, Si and A are present as a cation, while O is present as an anion.

EA, RE and A include different elements or ions. In particular, EA is not a rare earth metal ion.

The luminescent material preferably comprises a crystalline, for example ceramic, host lattice into which activator ions are introduced as foreign elements. The crystalline host lattice is preferably built up from a three-dimensional unit cell that is usually periodically repeated. In other words, the unit cell is the smallest recurring unit of the crystalline host lattice. The elements EA, RE, Al, Si and O each preferably occupy defined, symmetrically equivalent places within the three-dimensional unit cell of the host lattice. Such symmetrically equivalent places in a crystal are referred to as point positions. The activator ion A, the divalent cation EA and the rare earth metal ion RE preferably occupy the same point position. This means that either EA, RE or A are preferably located in places in the crystal that are defined by this point position.

The host lattice changes the electronic structure of the activator ion in such a way that electromagnetic radiation with a first wavelength range, hereinafter also referred to as primary radiation, is absorbed in the material and stimulates an electronic transition in the phosphor, which emits electromagnetic radiation with an emission spectrum of a second wavelength range, in the following also secondary radiation, goes back to the ground state. Thus, the activator ion introduced into the host lattice is responsible for the wavelength-converting properties of the phosphor.

The term “divalent cations” is understood here and in the following to mean elements with a valence of two, i.e. elements that are doubly positively charged in a chemical compound. In order to achieve a charge balance in the compound, two further elements, which are single negatively charged in the chemical compound, or another element which is doubly negatively charged in the chemical compound, can be part of the chemical substance.

A phosphor described here can emit secondary radiation in the yellow-green spectral range. The secondary radiation thus has wavelengths whose maximum lies in the range 500 nm to 600 nm. In particular, the phosphor can emit in the yellow-green spectral range when excited with blue and / or ultraviolet primary radiation. The primary radiation thus has wavelengths whose maximum is in the range 400 nm to 500 nm. In other words, the phosphor can absorb blue and / or ultraviolet primary radiation and emit converted, yellow-green secondary radiation.

Such a phosphor thus has optical properties comparable to those of the known phosphors LU ₃ Al ₅ O ₁₂ : Ce ³⁺ (LuAG) or Y ₃ Al ₅ O ₁₂ : Ce ³⁺ (YAG). The luminescent materials LuAG and YAG, both of which have a garnet structure type, however, have a high proportion of rare earth metal ions, in particular a high proportion of Lu and Y ions, and are therefore produced with a correspondingly high proportion of expensive and in some cases environmentally harmful educts. In addition, sufficiently efficient phosphors LuAG and YAG require high synthesis temperatures for production, which entails a considerable expenditure of energy and high energy costs.

The inventors have recognized that by reducing the proportion of rare earth metal ions, the proportion of inexpensive and less environmentally harmful starting materials for producing the phosphor can be increased. For example, the proportion of Lu in the known phosphor LU ₃ Al ₅ O _{12 is} 61.7 mol% and the proportion of Y in the known phosphor Y ₃ Al ₅ O _{12 is} 45.1 mol%, while the proportion of Y in one of the above general formula based phosphor Ca ₂ Y ₁ Al ₃ Si ₂ O _{12 is} only 18 mol% and in another phosphor based on the above general formula Ba ₂ Y ₁ Al ₃ Si ₂ O _{12 is} 13 mol%. In particular, the proportion of RE in the phosphor described here is reduced by partial replacement by divalent cations EA. This brings significant cost advantages in the production of luminescent materials as well as resource and environmental efficiency. Furthermore, the phosphors according to the invention require less high synthesis temperatures. The phosphors according to the invention can thus be produced at moderate synthesis temperatures, which increases the energy efficiency during production and additionally lowers the costs, namely the energy costs.

Despite the reduced proportion of rare earth metal ions, the phosphors described here have optical properties that are comparable to those of YAG and LuAG and can therefore replace them in the respective applications. Furthermore, the phosphors described here have a high stability and service life.

In addition, their emissions can also be tailored to the respective application by adapting the exact composition. By changing the exact composition of the phosphor, in particular the selection and proportion of EA and / or RE, the position and form of the emission can be varied, which leads to greater flexibility in the use of the phosphor than is the case with known phosphors such as, for example LuAG and YAG is the case.

According to at least one further embodiment, the phosphor is in the cubic space group Ia 3 d crystallizes. The phosphor such as YAG, LuAG and other already known phosphors of the grant structure type thus crystallize.

According to at least one further embodiment, the phosphor has a lattice parameter a, and 11.6 is less than or equal to a and a is less than or equal to 12.1, that is to say 11.6 a 12.1, in particular 11.75 applies is less than or equal to a and a is less than or equal to 12.00, i.e. 11.75 ≤ a ≤ 12.00. The lattice parameter a can be obtained by X-ray powder diffraction.

According to at least one further embodiment, EA is selected in the phosphor from a group comprising Mg, Ca, Sr, Ba and combinations thereof. In particular, EA is selected from a group consisting of Mg, Ca, Sr, Ba, and combinations thereof. One of the elements mentioned or combinations thereof can thus be present in the phosphor. Thus EA can be alkaline earth cations. In comparison to conventional phosphors such as YAG or LuAG, a certain proportion of rare earth metal ions RE is replaced by alkaline earth metal ions, which are used as divalent cations EA. Depending on how much EA, which EA or which combination of different EA is selected, the exact emission wavelength of the phosphor can be influenced.

According to one embodiment, EA is Ca. The use of Ca in the phosphor enables the use of particularly favorable starting materials.

In accordance with at least one further embodiment, RE is selected in the phosphor from a group which comprises trivalent rare metal ions and combinations thereof. In particular, RE is selected from a group comprising Y, Lu and combinations thereof. In particular, RE is selected from a group consisting of Y, Lu and combinations thereof. Additionally or alternatively, La and Gd are also particularly conceivable. One of the elements mentioned or combinations thereof can thus be present in the phosphor. Depending on which RE or which combination of different REs are selected, the exact emission wavelength of the phosphor can be influenced.

According to one embodiment, RE is Y. The higher the Y component in the phosphor, the more the emitted secondary radiation can be shifted in the direction of red.

In accordance with at least one further embodiment, A is selected in the phosphor from a group comprising Eu, Ce, Yb, Pr Sm and combinations thereof. In particular, A is selected from a group consisting of Eu, Ce, Yb, Pr Sm, and combinations thereof. With these activator ions, secondary radiation can be generated in the desired wavelength range, in particular in the yellow-green range.

According to one embodiment, A is selected as Ce. Ce causes the phosphor to emit yellow-green.

According to at least one further embodiment, in the phosphor of the general formula EA _(3-x) RE _x Al _{(2 + x)} Si _(3-x) O ₁₂ : A x = 1. The phosphor is thus in the form EA ₂ RE ₁ A1 ₃ Si ₂ O ₁₂ : A before. For example, the phosphor has the formula Ca ₂ Y ₁ A1 ₃ Si ₂ O ₁₂ : Ce. Due to its high Ca content and low Y content, such a luminescent material is particularly cost-effective and can also be produced in an environmentally friendly and energy-efficient manner.

According to at least one further embodiment, A in the phosphor has a concentration of up to and including 5 mol%, preferably up to and including 4 mol%, in relation to the total content of EA and RE.

angegeben, wobei EA ausgewählt ist aus der Gruppe der zweiwertigen Kationen, RE ausgewählt ist aus Seltenerdmetallionen, A ausgewählt ist aus Aktivatorionen, und 0 < x < 2 ist. Das Verfahren umfasst die Schritte

• - Bereitstellen eines stöchiometrischen Gemenges von Edukten, die aus einer Gruppe ausgewählt sind, die Oxide, Carbonate, Nitrate, Oxalate, Citrate und Hydroxide jeweils von EA, RE, Al, Si und A und Kombinationen daraus umfasst,
• - homogenes Vermengen der Edukte,
• - Erhitzen der Edukte auf eine Temperatur, die aus dem Bereich 800°C bis 1600°C, insbesondere aus dem Bereich 1100°C bis 1600°C ausgewählt ist.

A method for producing a phosphor is also specified. According to at least one embodiment, a method for producing a phosphor having the general formula $${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A.}$$

indicated, where EA is selected from the group of divalent cations, RE is selected from rare earth metal ions, A is selected from activator ions, and 0 <x <2. The method comprises the steps

• - Providing a stoichiometric mixture of starting materials selected from a group comprising oxides, carbonates, nitrates, oxalates, citrates and hydroxides of EA, RE, Al, Si and A and combinations thereof,
• - homogeneous mixing of the starting materials,
• Heating of the starting materials to a temperature which is selected from the range 800 ° C to 1600 ° C, in particular from the range 1100 ° C to 1600 ° C.

Optionally, flux can also be added to the mixture.

With the method, in particular a phosphor as described above can be produced. All of the features and embodiments disclosed in connection with the phosphor thus also apply to the method and vice versa.

The starting materials can also be referred to as EA oxides, EA carbonates, EA nitrates, etc. The group of possible starting materials thus includes EA-Oxide, EA-Carbonate, EA-Nitrate, EA-Oxalate, EA-Citrate, EA-Hydroxide, RE-Oxide, RE-Carbonate, RE-Nitrate, RE-Oxalate, RE-Citrate , RE-hydroxides, Al-oxides, Al-carbonates, Al-nitrates, Al-oxalates, Al-citrates, Al-hydroxides, Si-oxides, Si-carbonates, Si-nitrates, Si-oxalates, Si-citrates, Si -Hydroxides, A-oxides, A-carbonates, A-nitrates, A-oxalates, A-citrates, A-hydroxides and combinations thereof.

The starting materials, which are selected from oxides, carbonates, nitrates, oxalates, citrates and hydroxides of EA, RE, Al, Si and A as well as combinations thereof, are provided in a stoichiometric mixture that has a particularly low proportion of RE oxides or RE carbonates or RE nitrates or RE oxalates or RE citrates or RE hydroxides. A phosphor with a reduced rare earth metal ion content can thus be produced with the method.

The EA oxides include, for example, MgO, BaO, CaO and SrO, the EA carbonates include, for example, MgCO ₃ , BaCO ₃ , CaCO ₃ and SrCO ₃ , the EA nitrates include, for example, Mg (NO ₃ ) ₂ , Ba (NO ₃ ) ₂ , Ca (NO ₃ ) ₂ , Sr (NO ₃ ) ₂ . The RE oxides also include, for example, Y ₂ O ₃ and LU ₂ O ₃ , the RE carbonates for example Y ₂ (CO ₃ ) ₃ and Lu ₂ (CO ₃ ) ₃ , the RE nitrates for example Y (NO ₃ ) ₃ and Lu (NO ₃ ) ₃ . The A oxides include, for example, Eu ₂ O ₃ , Yb ₂ O ₃ , Pr ₂ O ₃ , Sm ₂ O ₃ , CeO ₂ , and the A carbonates include, for example, Eu ₂ (CO ₃ ) ₃ , Ce ₂ (CO ₃ ) ₃ , Yb ₂ (CO ₃ ) ₃ , Pr ₂ (CO ₃ ) ₃ and Sm ₂ (CO ₃ ) ₃ , and the A nitrates include, for example, Eu (NO ₃ ) ₃ , Ce (NO ₃ ) ₃ , Yb (NO ₃ ) ₃ , Pr (NO ₃ ) ₃ and Sm (NO ₃ ) ₃ . Al ₂ O ₃ can be selected as the Al oxide, for example Al (NO ₃ ) ₃ as the Al nitrate, for example Al (OH) ₃ as the Al hydroxide, and SiO ₂ , for example, as the Si oxide.

If the oxides are not selected directly as starting materials, they are formed as an intermediate in the synthesis process from the respective non-oxidic starting material.

The heating of the educts to the elevated temperature causes the educts to be converted into the phosphor. The corresponding temperature can thus also be referred to as the synthesis temperature. The exact synthesis temperature depends on the exact composition of the phosphor. The proportion of activator ions also has a significant influence on the synthesis temperature. For example, a change in the activator ion concentration can bring about a change in the reaction or synthesis temperature of up to 50.degree.

The process is carried out at lower temperatures than is the case with the known phosphors YAG and LuAG. While the already known phosphors YAG and LuAG usually have to be synthesized at around 1600 ° C., the phosphor according to the invention can be produced at temperatures below 1600 ° C. These moderate synthesis temperatures are made possible by the reduced proportion of educts of rare earth metal ions and require less energy and reduced energy costs.

In addition, the method can be used to produce a phosphor as described above in a comparatively simpler manner and with less effort, in particular also less financial effort, than is the case, for example, with LuAG and YAG, but also with nitridic phosphors.

The heating of the educts and thus the conversion of the educts to the phosphor can take place, for example, in an open corundum or nickel crucible. A nickel crucible can only be selected if the synthesis temperature is below the softening point of nickel. The reaction is usually carried out at high temperatures for at least two to four hours, but the optimum duration of the reaction depends on the exact composition.

According to at least one embodiment, the temperature is selected from the range 1200 ° C to 1400 ° C. This means that the temperature for converting the starting materials into the phosphor is significantly lower than in conventional processes.

According to at least one further embodiment, CaO or Ca ₂ CO ₃ , Y ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and CeO _{2 are} selected as starting materials. With these starting materials, for example, the phosphor Ca ₂ Y ₁ Al ₃ Si ₂ O ₁₂ : Ce can be produced.

According to at least one further embodiment, the heating is carried out under a forming gas atmosphere. This ensures reducing conditions during the conversion of the starting materials. The forming gas can be, for example, N ₂ with up to 9% H ₂ .

An optoelectronic component is also specified. The phosphor described above is particularly suitable and intended for use in an optoelectronic component. Features and embodiments that are described in connection with the phosphor and / or the method for producing a phosphor therefore also apply to the optoelectronic component and vice versa.

• - einen Halbleiterchip, der im Betrieb elektromagnetische Strahlung eines ersten Wellenlängenbereichs von einer Strahlungsaustrittsfläche emittiert, und
• - ein Konversionselement, das einen Leuchtstoff aufweist, der elektromagnetische Strahlung des ersten Wellenlängenbereichs in elektromagnetische Strahlung eines zweiten Wellenlängenbereichs konvertiert, wobei der Leuchtstoff die allgemeine Formel

$${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A}$$

aufweist, wobei

• - EA ausgewählt ist aus der Gruppe der zweiwertigen Kationen,
• - RE ausgewählt ist aus Seltenerdmetallionen,
• - A ausgewählt ist aus Aktivatorionen, und
• - 0 < x < 2 ist.

In accordance with at least one embodiment, the optoelectronic component comprises

• a semiconductor chip which, during operation, emits electromagnetic radiation of a first wavelength range from a radiation exit surface, and
• - A conversion element which has a phosphor which converts electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range, the phosphor having the general formula

$${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A.}$$

having, where

• - EA is selected from the group of divalent cations,
• - RE is selected from rare earth metal ions,
• - A is selected from activator ions, and
• - 0 <x <2.

The electromagnetic radiation of the first wavelength range forms the emission spectrum of the semiconductor chip and is also referred to as primary radiation.

The semiconductor chip is, for example, a light-emitting diode chip or a laser diode chip. The semiconductor chip preferably has an epitaxially grown semiconductor layer sequence with an active zone which is suitable for generating electromagnetic radiation. For this purpose, the active zone has, for example, a pn junction, a double heterostructure, a single quantum well or, particularly preferably, a multiple quantum well structure. During operation, the semiconductor chip preferably emits electromagnetic radiation from the ultraviolet spectral range and / or from the visible spectral range, particularly preferably from the blue spectral range. The primary radiation thus has, for example, wavelengths from the range 400 nm to 500 nm.

The phosphor in the conversion element converts electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range. The electromagnetic radiation of the second wavelength range forms the emission spectrum of the phosphor and is also referred to as secondary radiation.

The electromagnetic radiation of the second wavelength range is preferably at least partially different from the first wavelength range. The phosphor which is contained in the conversion element or from which the conversion element consists gives the conversion element wavelength-converting properties. For example, the conversion element only partially converts the electromagnetic radiation of the semiconductor chip into electromagnetic radiation of the second wavelength range, while a further part of the electromagnetic radiation of the semiconductor chip is transmitted by the conversion element. In this case, the optoelectronic component emits mixed light which is composed of electromagnetic radiation of the first wavelength range and electromagnetic radiation of the second wavelength range. The mixed light includes white light, for example. If the primary radiation is completely converted by the conversion element and / or if there is no transmission of primary radiation through the conversion element, this is referred to as full conversion. In this case, the optoelectronic component emits the secondary radiation emitted by the conversion element.

By changing the exact composition of the phosphor, the position and shape of the secondary radiation can be varied, which leads to greater flexibility when using the optoelectronic component. Furthermore, the component can be produced both cost-effectively and energy-efficiently, since the phosphor comprises a reduced proportion of rare earth ions and has a reduced synthesis temperature. In addition, due to its low melting temperature, the luminescent material can be processed directly into a ceramic which, for example, can be used well as a conversion material in components in which highly transparent properties or high thermal conductivities are required.

According to at least one embodiment, the conversion element is designed as a conversion layer. The conversion layer can be in direct or indirect contact with the radiation exit surface of the semiconductor chip be applied. In the case of indirect contact, it can be applied to the radiation exit surface with the aid of, for example, an adhesive layer, or a potting can be applied between the radiation exit surface and the conversion element.

According to a further embodiment, the semiconductor chip, conversion layer and, if appropriate, adhesive layer can also all be surrounded by an encapsulation. For example, the semiconductor chip, conversion element and, if necessary, an adhesive layer are then arranged in the recess of a housing in which the potting is also arranged.

A potting can have a permeability for the primary radiation and / or the secondary radiation that is at least 85%, preferably 95%. Furthermore, a potting can have silicone or epoxy resin as material, for example.

In accordance with at least one embodiment, the phosphor has a dominant wavelength in the range including 480 nm up to and including 585 nm, in particular in the range including 500 nm up to and including 565 nm. The dominant wavelength λ _dom is to be understood as an integral variable which reproduces the color of the emitted radiation that is perceived by the human eye. In general, the dominant wavelength deviates from the emission maximum. The phosphor has such a dominant wavelength in particular when excited with blue and / or ultraviolet primary radiation.

According to a further embodiment, the luminescent material has a main wavelength in the range from 520 nm to 590 nm inclusive, in particular in the range 534 nm to 569 nm. The focal wavelength λ _cent is an integral quantity that reflects the energetic position of the electromagnetic radiation. The luminescent material has such a focal wavelength in particular when excited with blue and / or ultraviolet primary radiation.

According to at least one further embodiment, the phosphor has an emission maximum in the green-yellow spectral range. In particular, it has such an emission maximum when excited with blue and / or ultraviolet primary radiation. For example, the emission maximum of the phosphor is between 500 nm and 590 nm inclusive, in particular between 500 nm and 550 nm inclusive.

The emission maximum is the wavelength at which the luminescent material or the semiconductor chip exhibits the greatest emission and can be determined using the emission spectrum.

According to at least one further embodiment, the phosphor is present in the conversion element as ceramic. In such a case, the conversion layer can consist of the phosphor forming the ceramic. Ceramic is well suited as a material for a conversion element because it is good at dissipating heat. Such conversion elements can therefore be used well in components that are operated with a lot of energy, such as, for example, car or stage lights.

In accordance with at least one further embodiment, the luminescent material is embedded in a matrix in the conversion element. In particular, the phosphor is then in particle form. Such a conversion element is inexpensive to manufacture and is particularly suitable for applications in which lower energies are used.

For example, the matrix can comprise a material selected from a group consisting of polymers and glass. Polystyrene, polysiloxane, polysilazane, PMMA, polycarbonate, polyacrylate, polytetrafluoroethylene, polyvinyl, silicone resin, silicone, epoxy resin and transparent synthetic rubber can be selected as polymers. For example, silicates, water glass and quartz glass can be selected as glass.

Further advantageous embodiments and developments of the component and of the method result from the exemplary embodiments described below in connection with the figures.

• 1 Emissionsspektren von Ausführungsbeispielen des Leuchtstoffs im Vergleich zu einem Referenzbeispiel,
• 2 und 3 Schematische Schnittdarstellungen von optoelektronischen Bauelementen gemäß verschiedenen Ausführungsbeispielen.

Show it:

• 1 Emission spectra of exemplary embodiments of the phosphor compared to a reference example,
• 2 and 3 Schematic sectional representations of optoelectronic components in accordance with various exemplary embodiments.

Identical, identical or identically acting elements are provided with the same reference symbols in the figures. The figures and the proportions of the elements shown in the figures are not to be regarded as being to scale. Rather, individual elements, in particular layer thicknesses, can be shown exaggeratedly large for better illustration and / or for better understanding.

According to exemplary embodiment 1), the phosphor is Ca ₂ Y ₁ Al ₃ Si ₂ O ₁₂ : Ce. This can, for example, be produced as follows: A stoichiometric composition or a stoichiometric mixture of the starting materials CaO (alternatively Ca ₂ CO ₃ ), Y ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and CeO ₂ is homogenized and in an open corundum or Nickel crucible implemented. The reaction takes place in a chamber furnace at about 1330 ° C. for four hours under a forming gas atmosphere, which is composed of N ₂ with up to 9% H ₂ .

The exact synthesis temperature depends on the exact composition of the phosphor and the activator concentration.

According to this process, phosphors of any composition within the general formula EA ( ₃ - _x ) RE _x Al _{(2 + x)} Si _(3-x) O ₁₂ : A can be produced. Table 1 shows sample weights for three different embodiments: Tab. 1 composition Educt Amount of substance [mmol] Weight [g] 1) Ca ₂ Y ₁ Al ₃ Si ₂ O ₁₂ : Ce CaCO ₃ 169.57 16.97 Y ₂ O ₃ 39.85 9.00 Al ₂ O ₃ 127.18 12.97 CeO ₂ 5.09 0.88 SiO ₂ 169.56 10.19 2) Sr ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce SrCO ₃ 130.60 19.28 Lu ₂ O ₃ 30.69 12.21 Al ₂ O ₃ 97.95 9.99 CeO ₂ 3.92 0.67 SiO ₂ 130.60 7.85 3) Ca ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce CaCO ₃ 149.1 14.92 Lu ₂ O ₃ 35.04 13.94 Al ₂ O ₃ 111.83 11.40 CeO ₂ 4.47 0.77 SiO ₂ 149.11 8.96

The numbering of the exemplary embodiments is also retained in the following. In addition, the exemplary embodiments 4) Mg ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce and 5) Ba ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce are given.

Table 2 shows an overview of the resulting dominant wavelengths λ _dom and focus wavelengths λ _cent when the fluorescent material is excited with blue and / or ultraviolet primary radiation with a wavelength of 460 nm in Examples 1 to 5: Tab. 2 composition λ _dom [nm] λ _cent [nm] 4) Mg ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce 500 534 3) Ca ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce 530 539 2) Sr ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce 543 557 5) Ba ₂ Lu ₁ Al ₃ Si ₂ O ₁₂ : Ce 545 549 1) Ca ₂ Y ₁ Al ₃ Si ₂ O ₁₂ : Ce 565 569

Based on the exemplary embodiments and the respective wavelengths, it can be seen that the replacement of smaller EA by larger EA, that is to say the replacement of Mg by Ca, of Ca by Sr and of Sr by Ba, as can be seen on the basis of embodiments 2) to 4) causes a shift to red, i.e. to longer wavelengths. The replacement of Lu by Y also causes a shift to red, which can be seen when comparing embodiments 1) and 3). These trends can be seen in both the dominant wavelength and the centroid wavelength.

Table 3 shows the dependence of the synthesis temperature on the activator ion concentration in the phosphor. On the basis of exemplary embodiment 1), the proportion of Ce in examples 1a) to 1g) was increased from 0.33 mol% to 5 mol% and the respective synthesis temperature was determined. Tab. 3 composition Synthesis temperature Ca ₂ Y ₁ Al ₃ Si ₂ O ₁₂ : yCe 1a) y = 0.01 1340 ° C 1b) y = 0.03 1335 ° C 1c) y = 0.05 1330 ° C 1d) y = 0.075 1325 ° C 1e) y = 0.1 1315 ° C 1f) y = 0.12 1305 ° C 1g) y = 0.15 1295 ° C

Based on the synthesis temperatures in Table 3, the relationship between activator ion concentration in the phosphor and synthesis temperature can be clearly seen. In particular, the synthesis temperature decreases with an increasing proportion of activator ions. With a higher activator ion concentration, even more energy-efficient phosphors can thus be provided.

1 shows emission spectra of working examples 1) to 3) in comparison with reference example LU ₃ Al ₅ O ₁₂ : Ce (LuAG). It can be seen that the emissions of the exemplary embodiments are comparable to the emissions of the reference example, the emissions of the exemplary embodiments varying slightly due to their different compositions. For example, embodiment 3) emits in the greenest range. It can thus be shown that with optical properties comparable to those of the reference example, the phosphor described here has a tailor-made emission desired for the respective application by adapting its composition.

At the same time, compared to LuAG (and also YAG), the phosphor has a significantly reduced proportion of rare earth metal ions, which results in a lower synthesis energy, as a result of which the phosphor can be produced at lower costs and with increased resource and environmental efficiency.

The 2 and 3 show various exemplary embodiments of optoelectronic components on the basis of schematic sectional views.

2 shows an optoelectronic component comprising a semiconductor chip 10 having. The semiconductor chip 10 emits electromagnetic radiation of a first wavelength range (primary radiation) during operation a radiation exit surface 11 . The semiconductor chip 10 has an epitaxially grown semiconductor layer sequence with an active zone 12 which is suitable for generating electromagnetic radiation. The primary radiation has wavelengths in the blue and / or ultraviolet range, for example.

The component also has a conversion element 20th on. The conversion element 20th either contains a matrix in which the luminescent material, in particular particles of the luminescent material, is embedded, or the conversion element has or consists of a ceramic formed from the luminescent material. The phosphor can either be selected from one of the exemplary embodiments 1) to 5), or any other composition based on the general formula EA _(3-x) RE _x Al _{(2 + x)} Si _(3-x) O ₁₂ : A have the properties described above. If the conversion element 20th has a matrix in which the phosphor is embedded, further phosphors can in principle also be embedded in the matrix. For example, a phosphor of the general formula EA ₍₃ - _x ) RE _x Al _{(2 + x)} Si _(3-x) O ₁₂ : A could be combined together with red-emitting phosphors in the matrix. The matrix has a material which is selected from polymers such as polystyrene, polysiloxane, polysilazane, PMMA, polycarbonate, polyacrylate, polytetrafluoroethylene, polyvinyl, silicone resin, silicone, epoxy resin and transparent synthetic rubber, and glass such as silicates, water glass and quartz glass.

During operation, the phosphor converts electromagnetic radiation of the first wavelength range into electromagnetic radiation of the second wavelength range (secondary radiation). The second wavelength range is at least partially different from the first wavelength range and has, for example, wavelengths in the yellow-green range. If the primary radiation is not completely converted by the conversion element, the component thus emits mixed light, which is composed of primary and secondary radiation.

The conversion element 20th , which is designed here as a conversion layer, can either be placed directly on the semiconductor chip 10 be applied, or for example by means of an adhesive layer (not explicitly shown here) attached to it.

The semiconductor chip 10 with the conversion element arranged on it 20th is in the recess of a housing 30th arranged. The case 30th has to the semiconductor chip 10 beveled side surfaces that can be reflective. The semiconductor chip 10 and the conversion element 20th can in the housing 30th from a potting 40 be surrounded, which is not explicitly shown here.

Alternatively, the housing 20th also have no side walls and thus no recess and be designed as a carrier (not shown here).

3 describes another embodiment of a component. For the elements with the same reference numerals, those with reference to FIG 2 made statements. In contrast to the component as shown in 2 is shown includes in 3 Component shown continues a potting 40 holding the semiconductor chip 10 surrounds. The encapsulation can for example be formed from a silicone or epoxy resin and has a permeability for electromagnetic radiation of the active zone 12 which is at least 85%, preferably 95%.

In this exemplary embodiment, the conversion element is 20th not directly on the semiconductor chip 10 arranged, but spaced apart from it on the of the semiconductor chip 10 facing away from the potting 40 . Here, too, is the conversion element 20th again designed as a conversion layer.

For the sake of clarity, the 2 and 3 additional elements, such as electrical contacts, are not shown.

The exemplary embodiments described in connection with the figures and their features can be combined with one another in accordance with further exemplary embodiments, even if such combinations are not explicitly shown in the figures. Furthermore, the exemplary embodiments described in connection with the figures can have additional or alternative features according to the description in the general part.

The description based on the exemplary embodiments is not restricted to the invention. Rather, the invention encompasses every new feature and every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.

List of reference symbols

10

Semiconductor chip

11

Radiation exit surface

12

Active zone

20th

Conversion element

30th

casing

40

Potting

Claims (20)

Phosphor with the general formula $${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A.}$$

where - EA is selected from the group of divalent cations, - RE is selected from rare earth metal ions, - A is selected from activator ions, and - 0 <x <2. Phosphor according to the preceding claim, which is in the cubic space group Ia 3 d is crystallized. Phosphor according to the preceding claim, which has a lattice parameter a, and 11.6 is less than or equal to a and a is less than or equal to 12.1. The phosphor according to any one of the preceding claims, wherein EA is selected from a group comprising Mg, Ca, Sr, Ba and combinations thereof. The phosphor according to any one of the preceding claims, wherein RE is selected from a group comprising trivalent rare earth metal ions and combinations thereof. The phosphor according to any one of the preceding claims, wherein A is selected from a group comprising Eu, Ce, Yb, Pr, Sm and combinations thereof. Phosphor according to one of the preceding claims, wherein x = 1. A phosphor according to any preceding claim, wherein EA is Ca. A phosphor according to any preceding claim, wherein RE is Y. A phosphor according to any preceding claim, wherein A is Ce. Phosphor according to one of the preceding claims, wherein A has a concentration of up to and including 5 mol% in relation to the total content of EA and RE. Process for producing a phosphor having the general formula $${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A.}$$

where - EA is selected from the group of divalent cations, - RE is selected from rare earth metal ions, - A is selected from activator ions, and - 0 <x <2, with the steps - Providing a stoichiometric mixture of starting materials selected from a group comprising oxides, carbonates, nitrates, oxalates, citrates and hydroxides of EA, RE, Al, Si and A and combinations thereof, - homogeneous mixing of the starting materials, - heating the starting materials to a temperature which is selected from the range 800 ° C to 1600 ° C. Method according to the preceding claim, wherein the temperature is selected from the range 1200 ° C to 1400 ° C. Method according to one of the Claims 12 and 13 , CaO or Ca ₂ CO ₃ , Y ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and CeO _{2 being} selected as starting materials. Method according to one of the Claims 12 to 14th , wherein the heating is carried out under a forming gas atmosphere. Optoelectronic component, comprising - a semiconductor chip (10) which, during operation, emits electromagnetic radiation of a first wavelength range from a radiation exit surface (11), and - a conversion element (20) which has a phosphor that converts electromagnetic radiation of the first wavelength range into electromagnetic radiation second wavelength range converted, the phosphor having the general formula $${\text{EA}}_{\left(3-\text{x}\right)}{\text{RE}}_{\text{x}}{\text{Al}}_{\left(2+\text{x}\right)}{\text{Si}}_{\left(3-\text{x}\right)}{\text{O}}_{12}:\text{A.}$$

wherein - EA is selected from the group of divalent cations, - RE is selected from rare earth metal ions, - A is selected from activator ions, and - 0 <x <2. Optoelectronic component according to Claim 15 wherein the phosphor has a dominant wavelength in the range 480 nm to 585 nm inclusive. Optoelectronic component according to one of the Claims 16 and 17th wherein the phosphor has a centroid wavelength in the range from 520 nm to 590 nm inclusive. Optoelectronic component according to one of the Claims 16 to 18th , wherein the phosphor in the conversion element (20) is present as ceramic. Optoelectronic component according to one of the Claims 16 to 18th , wherein the phosphor in the conversion element (20) is embedded in a matrix.

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