Structure, arrangement, method for producing a structure, method for producing an arrangement, and optoelectronic device

Abstract

A structure is specified. According to one embodiment, the structure (1) comprises an emitter particle (2) configured to convert a primary radiation into a secondary radiation, and a barrier layer (3) at least partially surrounding the emitter particle (2), wherein the barrier layer (3) comprises a non-crystalline matrix (31) and a plurality of crystalline nanoparticles (32). Furthermore, an arrangement, a method for producing a structure, a method for producing an arrangement, and an optoelectronic device, in particular comprising a micro-LED, are specified.

Description

[0001] Description

[0002] STRUCTURE, ARRANGEMENT, METHOD FOR PRODUCING A STRUCTURE, METHOD FOR PRODUCING AN ARRANGEMENT, AND OPTOELECTRONIC DEVICE

[0003] A structure, an arrangement, a method for producing a structure, a method for producing an arrangement, and an optoelectronic device are specified.

[0004] It is an object to provide a structure with improved efficiency. It is a further object to provide an arrangement with improved efficiency. Additionally, it is an object to provide a simple method for producing a structure with improved efficiency. Furthermore, it is an object to provide simple method for producing an arrangement with improved efficiency. Moreover, it is an object to provide an optoelectronic device with improved efficiency.

[0005] A structure is specified. In particular, the structure is a nanoparticle. A nanoparticle is a small object with dimensions in the nanometer range. The structure can be a spherical and / or an elongated structure.

[0006] According to at least one embodiment, the structure comprises an emitter particle configured to convert a primary radiation into a secondary radiation. The primary radiation and the secondary radiation can at least partially differ from each other. For example, the emitter particle absorbs the primary radiation, converts the primary radiation into secondary radiation, and emits the secondary radiation. In particular, a wavelength or wavelength range of the secondary radiation is in the visible or infrared wavelength range of the electromagnetic spectrum, for example , between and including 500 nm and 2000 nm, for instance , between and including 500 nm and 1000 nm . for example , the emitter particle comprises or consists of a phosphor material or a semiconductor structure comprising at least one semiconductor nanocrystal .

[0007] According to at least one embodiment , the structure comprises a barrier layer at least partially, in particular completely, surrounding the emitter particle . In particular, the barrier layer is an individual conformal coating of the emitter particle . For example , the barrier layer is configured to protect the emitter particle against deleterious or damaging species such as water, humidity, or other unwanted chemical species .

[0008] According to at least one embodiment , the barrier layer comprises a non-crystalline matrix and a plurality of crystalline nanoparticles . In particular, the plurality of crystalline nanoparticles is distributed within the noncrystalline matrix . For example , the plurality of crystalline nanoparticles is packed around the emitter particle within the non-crystalline matrix . The crystalline nanoparticles can have a spherical , spheroidal , tetrahedral , and / or cuboid shape .

[0009] Here and in the following, a crystalline nanoparticle is a nanoparticle whose constituents are arranged in a highly ordered microscopic structure , thereby forming a crystal lattice that extends in all directions of the nanoparticle . In particular, the crystalline nanoparticle has a homogeneous crystal lattice . In a crystalline nanoparticle , the constituents have a short-range order, a medium-range order, and a long-range order . For example , the short-range order extends over one to two atomic spacings . For example , the medium-range order is a structural organi zation extending beyond the short-range order, usually by 1-2 nm . for example , the long-range order is the structural organi zation extending beyond the medium-range order .

[0010] Here and in the following, a non-crystalline matrix is a material having an internal structure comprising interconnected structural blocks that can be similar to the basic structural units formed in the corresponding crystalline phase of the same material . Unlike in crystalline materials , no long-range order exists . The non-crystalline matrix therefore cannot be defined by a finite unit cell . The non-crystalline matrix can have a short-range order . Additionally, the non-crystalline matrix can have a mediumrange order . In particular, the non-crystalline matrix is free of a long-range order .

[0011] In particular, the non-crystalline matrix has a smaller density than the crystalline nanoparticles . For example , the crystalline nanoparticles have a higher stability against deleterious or damaging species such as water, humidity, or other unwanted chemical species compared to the noncrystalline matrix .

[0012] In particular, the non-crystalline matrix is an amorphous matrix or a densi fied matrix . An amorphous matrix, for instance , only has a short-range order . A densi fied matrix, for instance , has a short-range order and a medium-range order . A densi fied matrix can be produced by sintering an amorphous matrix . Alternatively or additionally, a hydroxyl group content of the material can be a measure for the crystallinity of the material. The more hydroxyl groups present in a material, the less crystalline the material is. Thus, the non-crystalline matrix comprises, for example, more hydroxyl groups than the crystalline nanoparticles. Further, an amorphous matrix, for example, comprises more hydroxyl groups than a densified matrix. In other words, densif ication means here and in the following that a larger percentage of the hydroxyl groups have been bonded together via a condensation reaction.

[0013] For example, the crystallinity of the material is monitored via thermogravimetric analysis and / or infrared spectroscopy and / or Raman spectroscopy.

[0014] For instance, infrared spectroscopy of silica shows differences in an intensity of IR-active bands around 800 cm-1(Si-0 asymmetric stretch) , around 1100 cm-1(C-0 asymmetric stretch) , around 1170 cm-1(CH3rocking) and around 1400 cm-1(CH2wagging) depending on the crystallinity of the silica. The intensity of all these bands may decrease as the crystallinity increases. For example, the absorption of amorphous silica around 800 cm-1is broader and weaker than the well-defined sharp doublet at 800 cm-1 and 780 cm-1of crystalline silica. In addition, the IR-active band around 1080 cm-1(Si-O-Si stretch) can increase with increasing crystallinity. Further, an IR-active band at 695 cm-1can only be observed in crystalline silica.

[0015] For instance, Raman spectroscopy of silica shows differences in an intensity of Raman-active bands corresponding to a strongly polarized Si-0 symmetric stretch (656 cm-1) and a depolari zed CH3rocking ( 960 cm-1) . The intensity of all these bands may decrease as the crystallinity increases .

[0016] According to at least one embodiment , the structure comprises an emitter particle configured to convert a primary radiation into a secondary radiation, and a barrier layer at least partially surrounding the emitter particle , wherein the barrier layer comprises a non-crystalline matrix and a plurality of crystalline nanoparticles .

[0017] It is an idea of the present application to provide a structure having a barrier layer with mixed states of crystallinity . This allows for maximi zing the fraction of crystallinity in the barrier layer around the emitter particle . In particular, the maj ority of the barrier layer is crystalline and only a minimal amount of non-crystalline matrix is used to fill in the gaps between the crystalline nanoparticles . This reduces the need for sintering of sensitive materials and improves the barrier layer properties of the barrier layer by creating a tortuous path for water or other unwanted chemical species to reach the surface of the emitter particle that is being protected by the barrier layer . Crystalline nanoparticles hold up much better against water and humidity compared to the non-crystalline matrix alone . Thus , the stability of the structure and the emitter particle can be increased, in particular under high humidity conditions . Further, by using crystalline nanoparticles in the non-crystalline matrix, a porosity of the barrier layer can be decreased compared to a barrier layer made of the noncrystalline matrix alone .

[0018] According to at least one embodiment , the structure is a discrete nanoparticle . A discrete nanoparticle is a small obj ect with dimensions in the nanometer range that is separated by finite intervals or distances from other discrete nanoparticles , for example , in a plurality of discrete nanoparticles . In particular, a discrete nanoparticle is distinguishable from any other nanoparticle . For example , a discrete nanoparticle constitutes a separate entity and is individually distinct . For instance , a discrete nanoparticle is not a section or segment of a layer comprising emitter particles mixed in a matrix . Instead, a discrete nanoparticle is produced by building the barrier layer around the emitter particle .

[0019] According to at least one embodiment , the structure comprises an extension of at most 1000 nm along its largest dimension .

[0020] According to at least one embodiment , the barrier layer forms a discrete layer around the emitter particle . In particular, the barrier layer is an individual layer around the emitter particle . For example , the barrier layer is clearly, individually, and distinctly associated with the emitter particle . For instance , the barrier layer is a conformal coating of the emitter particle . In particular, the barrier layer is produced by building the barrier layer around the emitter particle . With the barrier layer forming a discrete layer around the emitter particle , a higher loading of the barrier layer with crystalline nanoparticles can advantageously be achieved compared to mixing the emitter particle and the crystalline nanoparticles in the matrix to form a layer .

[0021] According to at least one embodiment , each crystalline nanoparticle of the plurality of crystalline nanoparticles comprises a diameter of at least 3 nm or at least 4 nm . In particular, each crystalline nanoparticle of the plurality of crystalline nanoparticles comprises a diameter of at most 500 nm . For example , the plurality of crystalline nanoparticles can comprise an average diameter of 10 nm, 20 nm, or 150 nm . For instance , the plurality of crystalline nanoparticles comprises a monodispersity of less than or equal to 10 % . In particular, it may be beneficial to select the diameter of the crystalline nanoparticles to be as small as possible while having a diameter of at least 3 nm as a si ze of voids between the crystalline nanoparticles in the barrier layer decreases with decreasing diameter of the crystalline nanoparticles . A diameter of at least 3 nm can be advantageous to ensure that the crystalline nanoparticles have a suf ficient crystallinity .

[0022] According to at least one embodiment , the plurality of crystalline nanoparticles forms a random close packing in the barrier layer . In particular, a random close packing is an empirical parameter used to characteri ze the maximum volume fraction of the crystalline nanoparticles in the barrier layer when the crystalline nanoparticles are packed randomly . The random close packing describes the maximum density of the crystalline nanoparticles in the matrix without packing into an ordered structure such as a regular crystal lattice . The random close packing achievable can be depending on the packing procedure . In this instance , the term random close packing refers to a random close packing achieved by adding the crystalline nanoparticles into the reaction that is used to surround the emitter particle with the barrier layer . In particular, the random close packing is achieved by chemically adhering the crystalline nanoparticles to one another during surrounding the emitter particle with the barrier layer . Alternatively, the random close packing can be achieved by a polarity driven or solubility driven reaction during surrounding the emitter particle with the barrier layer .

[0023] In particular, the emitter particle is surrounded with the crystalline nanoparticles to the greatest extent possible . For example , the local packing fraction of the crystalline nanoparticles in the barrier layer is more than 60 % . In contrast , a conventional refractive index matching layer comprising emitter particles and scattering particles mixed in a matrix material can have a maximum loading of 60 weight / before it can no longer be mixed or dispensed . Thus , a higher loading of crystalline nanoparticles in the barrier layer can advantageously be achieved compared to , for example , a conventional refractive index matching layer achieved through mixing .

[0024] According to at least one embodiment , the plurality of crystalline nanoparticles is bonded together by the noncrystalline matrix . In particular, the non-crystalline matrix surrounds the plurality of crystalline nanoparticles at least partially, in particular completely, thereby holding the crystalline nanoparticles together . Additionally, direct chemical bonds can be formed between the crystalline nanoparticles and / or between the crystalline nanoparticles and the matrix . In this way, the barrier layer can advantageously be particularly stable .

[0025] According to at least one embodiment , the non-crystalline matrix fills gaps , voids , and / or interstices between the plurality of crystalline nanoparticles within the barrier layer, in particular completely . In particular, the crystalline nanoparticles are arranged in close proximity to one another, directly adj acent to one another or chemically bonded to one another around the emitter particle . In this instance , even in the case of a random close packing of the crystalline nanoparticles , gaps , voids , and / or interstices between the crystalline nanoparticles are formed . The noncrystalline matrix can surround the plurality of crystalline nanoparticles and, due to its non-crystalline nature , be located in the gaps , voids , and / or interstices . For instance , the emitter particle is surrounded with the crystalline nanoparticles to the greatest extent possible and the gaps , voids , and / or interstices are filled with the non-crystalline matrix . By filling gaps , voids , and / or interstices between the plurality of crystalline nanoparticles with the noncrystalline matrix, the stability and thus the protective properties of the barrier layer can advantageously be improved .

[0026] According to at least one embodiment , the non-crystalline matrix comprises a first material . In particular, the first material is a metal oxide . For example , the first material is at least one of silica, titania, zirconia, alumina, magnesium oxide , hafnia, barium oxide , bismuth oxide , tin oxide , or mixed oxides . For instance , the first material is silica .

[0027] According to at least one embodiment , the plurality of crystalline nanoparticles comprises the first material . In particular, the non-crystalline matrix comprises the first material in a non-crystalline form and the plurality of crystalline nanoparticles comprises the first material in crystalline form . By using the first material for the noncrystalline matrix and the plurality of crystalline nanoparticles , the crystalline nanoparticles advantageously do not influence the optical properties of the barrier layer and, thus, the optical properties of the structure can be maintained .

[0028] According to at least one embodiment, the plurality of crystalline nanoparticles comprises a second material different from the first material. By choosing a different material for the crystalline nanoparticles, further properties of the barrier layer such as scattering properties, the refractive index, or the dielectric constant can advantageously be tailored to specific applications. For example, light extraction through appropriate matching of an index of refraction at a given wavelength can be adjusted as needed by selecting a suitable material for the crystalline nanoparticles .

[0029] In particular, the second material is a metal oxide, a metal chacogenide, a metal pnictide, or a metal.

[0030] For example, the metal oxide is at least one of silica, titania, zirconia, alumina, magnesium oxide, hafnia, barium oxide, bismuth oxide, tin oxide, or mixed oxides. For instance, the second material is zirconia. Zirconia has a high refractive index. By selecting zirconia for the crystalline nanoparticles, the refractive index of the barrier layer can advantageously be increased.

[0031] For example, the metal chalcogenide is a chemical compound consisting of at least one chalcogen anion of the group 16 elements of the periodic table and at least one or more metal cation. In particular, the metal chalcogenide is a metal sulfide or a metal selenide. For example, the metal sulfide is zinc sulfide. Zinc sulfide nanoparticles can be used if no absorption in the visible spectrum is a requirement for the structure . For example , the metal selenide is zinc selenide or cadmium selenide .

[0032] For example , the metal pnictide is a chemical compound consisting of at least one pnictogen anion of the group 15 elements of the periodic table and at least one or more metal cation . In particular, the metal pnictide is a metal phosphide or a metal arsenide . For example , the metal pnictide is gallium phosphide or indium phosphide . For example , the metal arsenide is gallium arsenide .

[0033] For example , the metal is gold . By using metal nanoparticles , in particular gold nanoparticles , as crystalline nanoparticles , a field enhancement around the emitter particle and the structure can advantageously be improved .

[0034] The field enhancement around the emitter particle can influence how electromagnetic radiation comes to the emitter particle .

[0035] According to at least one embodiment , the emitter particle comprises a phosphor material . The phosphor material can be an inorganic phosphor material , an organic phosphor material or an inorganic-organic hybrid phosphor material .

[0036] According to at least one embodiment , the emitter particle comprises a semiconductor structure comprising at least one semiconductor nanocrystal . The semiconductor nanocrystal is , in particular, an emitter particle having a diameter of between and including 1 nm and 100 nm, for example between and including 2 nm and 20 nm, for instance between and including 2 nm and 10 nm . Due to their small si ze , semiconductor nanocrystals have di f ferent properties than a bulk material formed from the same material . It is possible that the semiconductor nanocrystal is spherical , rod-shaped, or cuboid . For example , a surface of the semiconductor nanocrystal is uni form or uneven . The semiconductor nanocrystal is , in particular, a discrete nanoparticle . In particular, the semiconductor nanocrystal is a nanoparticle with a mostly crystalline structure , for example , a semiconductor nanoparticle or a quantum dot . In particular, the semiconductor nanocrystal is composed of atoms in a single- or polycrystalline arrangement . For example , the semiconductor nanoparticle is formed from at least one semiconductor material .

[0037] According to at least one embodiment , the semiconductor nanocrystal comprises a core or a core and at least one shell . In particular, the semiconductor nanocrystal consists of the core or has a core-shell structure . For example , the core has a diameter of between 2 nm and 5 nm . For instance , the at least one shell has a thickness between and including 0 nm and 3 nm . The core and / or the at least one shell may comprise at least one semiconductor material . In particular, the core comprises a di f ferent semiconductor material than the shell . For instance , the at least one shell is grown onto the core . The semiconductor nanocrystal can comprise further shells and / or layers such as passivation layers . For instance , the semiconductor nanocrystal comprises a quantum well structure . In particular, the semiconductor nanocrystal is a core quantum dot or a core-shell quantum dot or a core- shell-shell quantum dot or a quantum well quantum dot .

[0038] According to at least one embodiment , the semiconductor structure comprises an encapsulation layer at least partially, in particular completely, surrounding the semiconductor nanocrystal . For example , the encapsulation layer comprises or consists of a metal oxide , for example , at least one of silica, titania, zirconia, alumina, magnesium oxide , hafnia, barium oxide , bismuth oxide , tin oxide , or mixed oxides . For instance , the encapsulation layer comprises or consists of silica . The semiconductor structure can further comprise a linker layer between the semiconductor nanocrystal and the encapsulation layer . In particular, the linker layer is formed as a monolayer on a surface of the semiconductor nanocrystal . For example , the linker layer comprises or consists of sul fur or ( 3- aminopropyl ) trimethoxysilane (APTMS ) . An encapsulation layer surrounding the semiconductor nanocrystal can advantageously further protect the semiconductor nanocrystal against degradation .

[0039] According to at least one embodiment , the semiconductor structure comprises a cluster of a plurality of semiconductor nanocrystals . In particular, the cluster is an aggregate of a plurality of semiconductor nanocrystals or an agglomerate of a plurality of semiconductor nanocrystals . Here and in the following, an aggregate is to be understood as an association of particles having reversible connections between the individual particles . Here and in the following an agglomerate is to be understood as an association of particles having irreversible connections between the individual particles . In particular, each semiconductor nanocrystal of the plurality of semiconductor nanocrystals is individually surrounded by an encapsulation layer . Alternatively or additionally, the cluster of the plurality of semiconductor nanocrystals is surrounded by an encapsulation layer . A semiconductor structure comprising a cluster of semiconductor nanocrystals can advantageously increase the light converting ef ficiency of the structure . Furthermore , an arrangement is speci fied . In particular, the arrangement comprises a plurality of structures described herein . Thus , embodiments , features , and advantages described in combination with the structure also apply to the arrangement and vice versa .

[0040] According to at least one embodiment , the arrangement comprises a cluster of a plurality of structures described herein and a barrier layer at least partially surrounding the cluster, wherein the barrier layer comprises a noncrystalline matrix and a plurality of crystalline nanoparticles .

[0041] In particular, the cluster is an aggregate or an agglomerate of the plurality of structures . In particular, the barrier layer surrounding the cluster corresponds essentially to the barrier layer surrounding the emitter particle described above . Thus , embodiments , features , and advantages described in combination with the barrier layer surrounding the emitter particle also apply to the barrier layer surrounding the cluster and vice versa .

[0042] In particular, the arrangement is a discrete nanoparticle . For example , the arrangement comprises an extension of at most 50000 nm along its largest dimension . For instance , the arrangement comprises an extension of at least 50 nm along its shortest dimension . For example , the arrangement comprises an extension of 200 nm or 300 nm along its largest dimension .

[0043] In particular, the arrangement comprises a plurality of barrier layers as each structure in the cluster comprises a barrier layer and a barrier layer surrounds the cluster . The barrier layers in the arrangement can have an identical , a similar or a di f ferent composition regarding materials of the non-crystalline matrix and the crystalline nanoparticles as well as si zes such as diameters and si ze distributions such as monodispersity of the crystalline nanoparticles . For example , the barrier layers can have similar or mixed si zes of crystalline nanoparticles .

[0044] In particular, the arrangement comprises a plurality of clusters of structures surrounded with a barrier layer that is clustered and subsequently surrounded with a further barrier layer . The concept of forming clusters and surrounding the clusters with a barrier layer can be repeated multiple times , for example up to thousands of times , in order to produce an arrangement comprising a multitude of emitter particles protected by a multitude of barrier layers .

[0045] The arrangement described herein advantageously comprises a plurality of barrier layers . At least , the arrangement comprises a barrier layer within each structure and a barrier layer surrounding the cluster of structures . With the plurality of barrier layers , the barrier layer properties of the barrier layer are further increased by further extending the tortuous path for water or other unwanted chemical species to reach the surface of the emitter particle that is being protected by the barrier layers .

[0046] Furthermore , a method for producing a structure is speci fied . In particular, the structure described herein is produced by the method for producing a structure . Thus , embodiments , features , and advantages described in combination with the structure and the arrangement also apply to the method for producing a structure and vice versa .

[0047] According to at least one embodiment , the method comprises providing an emitter particle configured to convert a primary radiation into a secondary radiation and surrounding the emitter particle at least partially with a barrier layer, wherein the barrier layer comprises a non-crystalline matrix and a plurality of crystalline nanoparticles .

[0048] In particular, the method for producing a structure is a method for producing a plurality of structures . In this instance , a plurality of emitter particles is provided and the subsequent method steps are performed with the plurality of emitter particles .

[0049] With such a method, a structure having improved protective properties can advantageously be produced simply and cost- ef ficiently . A robust barrier layer can be achieved without exposing sensitive emitter particles to excessive temperatures during forming of the barrier layer . The barrier layer comprising crystalline nanoparticles and the noncrystalline matrix creates a more tortuous path for water, humidity, or other unwanted chemical species to reach the surface of the emitter particle that is being protected .

[0050] According to at least one embodiment , prior to surrounding the structure at least partially with the barrier layer, the plurality of crystalline nanoparticles is formed . In particular, the plurality of crystalline nanoparticles is grown . By forming the plurality of crystalline nanoparticles prior to surrounding the structure , the si ze such as the diameter and the si ze distribution such as the monodispersity of the plurality of crystalline nanoparticles can be customi zed as desired and tailored to speci fic applications .

[0051] According to at least one embodiment , prior to surrounding the structure at least partially with the barrier layer, a surface of the plurality of crystalline nanoparticles is functionali zed . In particular, the crystalline nanoparticles are functionali zed and then bridged into the non-crystalline matrix . Depending on the nature of the crystalline material , the speci fics of the chemistry may vary . By functionali zing a surface of the crystalline nanoparticles , the introducability of the crystalline nanoparticles into the non-crystalline matrix can advantageously be increased .

[0052] In particular, the surface is functionali zed by introducing hydroxyl groups on the surface . In other words , by functionali zing the surface , a hydroxyl-rich surface is formed . For example , the crystalline nanoparticles are incorporated into the non-crystalline matrix by having a layer of hydroxyl groups on the surface to be able to integrate into the network of the non-crystalline matrix . For instance , the surface , in particular a crystalline silica surface , is functionali zed by treating the surface with an acid such as sul furic acid . By treating a crystalline silica surface with sul furic acid, for example , a siloxane bond is cleaved resulting in a hydroxyl group on the surface . For example , hydroxyl groups on the surface are incorporated into the matrix through condensation reactions . The condensation reaction can be driven by temperature or a vacuum . Alternatively, the bridging can be driven through ether formation, for example , with small diols or polyols such as glycerin . In particular, the surface is functionali zed by introducing bromide on the surface . For example , boron tri-bromide is used for introducing bromide on the surface . Subsequently, organic chemistries could be employed to bridge the functionali zed crystalline nanoparticles and the noncrystalline matrix . For example , for crystalline silica nanoparticles , Si-Br bond are changed for an Si-CN which can be bridged to the non-crystalline matrix by a variety of chemistry options .

[0053] According to at least one embodiment , during surrounding the structure at least partially with the barrier layer, the plurality of crystalline nanoparticles is added to a precursor of the non-crystalline matrix . In particular, the barrier layer is grown on the surface of the emitter particle . For example , the non-crystalline matrix is grown from the precursor on the surface of the emitter particle and the plurality of crystalline nanoparticles is added into the growing layer of non-crystalline matrix material . For instance , the barrier layer is produced in a reverse micelle reaction or via Stober growth . The precursor can form the non-crystalline matrix by a condensation reaction . Here and in the following, a condensation reaction is a chemical reaction that connects at least two reactants while eliminating water or some other small molecule . The reaction of incorporating the crystalline nanoparticles can be driven by the chemical adhering of the , in particular functionali zed, crystalline surfaces of the crystalline nanoparticles with one another or with the matrix material , for example by performing condensation reactions .

[0054] Alternatively or additionally, the reaction can be polarity driven, and / or solubility driven and / or pH driven and / or catalyst driven . For instance , the non-crystalline matrix material comprises silica and the precursor is tetraethyl orthosilicate (TEOS) or tetramethyl orthosilicate (TMOS) . By adding the crystalline nanoparticles to the precursor of the non-crystalline matrix, a higher loading of the crystalline nanoparticles in the barrier layer can advantageously be achieved compared to a layer produced by mixing a matrix, nanoparticles, and emitter particles.

[0055] According to at least one embodiment, after surrounding the structure at least partially with the barrier layer, the noncrystalline matrix densified. In particular, the noncrystalline matrix is applied to the emitter particle in amorphous form and subsequently densified. For example, the non-crystalline matrix is densified by chemical treatment, heat treatment, or by exposing to UV light. For instance, the non-crystalline matrix is densified by heating to a temperature of at most 250 °C. For example, the temperature is increased to the point that sintering or calcination of the non-crystalline matrix can occur. By densifying the noncrystalline matrix, a porosity of the non-crystalline matrix can advantageously be decreased and thus, the protection properties of the barrier layer can be further increased.

[0056] Furthermore, a method for producing an arrangement is specified. In particular, the arrangement described herein is produced by the method for producing an arrangement. Thus, embodiments, features, and advantages described in combination with the structure, the arrangement, and the method for producing a structure also apply to the method for producing an arrangement and vice versa.

[0057] According to at least one embodiment, the method comprises performing the following method sequence: - providing a plurality of starting materials , wherein the starting material is a structure described herein or a structure produced by the method for producing a structure described herein,

[0058] - forming a cluster of the plurality of starting materials ,

[0059] - surrounding the cluster at least partially with a barrier layer to form a product , wherein the barrier layer comprises a non-crystalline matrix and a plurality of crystalline nanoparticles .

[0060] In particular, the cluster is an aggregate or an agglomerate of the plurality of structures . In particular, the method step of surrounding the cluster with the barrier layer corresponds essentially to the method step of surrounding the emitter particle with the barrier layer described above . Thus , embodiments , features , and advantages described in combination with surrounding the emitter particle with the barrier layer also apply to surrounding the cluster with the barrier layer and vice versa .

[0061] In particular, the product produced with the method sequence is the arrangement . Alternatively, the product can be an intermediate product that can be used as a starting material for further reactions .

[0062] With such a method, an arrangement having improved protective properties due to the plurality of barrier layers can advantageously be produced simply and cost-ef f iciently . With the plurality of barrier layers , the barrier layer properties of the barrier layer are further increased by further extending the tortuous path for water or other unwanted chemical species to reach the surface of the emitter particle that is being protected by the barrier layers . According to at least one embodiment , the method comprises repeating the method sequence , wherein the product is used as the starting material . The method step of repeating the method sequence , wherein the product is used as the starting material , can be repeated multiple times , for example up to thousands of times . In particular, the product is the product produced in the preceding method sequence . In other words , the product produced in the preceding method sequence is the starting material for the subsequent method sequence . By repeating the method sequence and using the product as the starting material , an arrangement comprising a multitude of emitter particles protected by a multitude of barrier layers can advantageously be produced simply and cost-ef f iciently .

[0063] Furthermore , an optoelectronic device is speci fied . In particular, the optoelectronic device comprises at least one structure and / or at least one arrangement described herein . Thus , embodiments , features , and advantages described in combination with the structure , the arrangement , the method for producing a structure , and the method for producing an arrangement also apply to the optoelectronic device and vice versa .

[0064] According to an embodiment , the optoelectronic device comprises a semiconductor chip configured to emit a primary radiation . In other words , the semiconductor chip is configured to emit electromagnetic radiation of a first wavelength range . In particular, the primary radiation comprises wavelengths in the ultraviolet to blue spectral region . According to at least one embodiment , the optoelectronic device comprises a conversion element comprising at least one structure , in particular a plurality of structures , and / or at least one arrangement , in particular a plurality of arrangements , described herein . In particular, the conversion element is configured to convert at least a part of the primary radiation into a secondary radiation . In other words , the conversion element converts the electromagnetic radiation of the first wavelength range into electromagnetic radiation of a second wavelength range . For example , the first wavelength range is at least partially di f ferent from the second wavelength range . For instance , the second wavelength range comprises wavelengths having a lower energy compared to the wavelengths in the first wavelength range . In particular, an ability of the conversion element to convert electromagnetic radiation is attributed to the structure which comprises the emitter particle converting primary radiation into secondary radiation and / or to the arrangement which comprises a plurality of structures each comprising the emitter particle converting primary radiation into secondary radiation .

[0065] According to at least one embodiment , the optoelectronic device comprises a semiconductor chip configured to emit a primary radiation, and a conversion element comprising at least one structure described herein and / or at least one arrangement described herein .

[0066] Advantageously, the optoelectronic device described herein has an improved ef ficiency, in particular in high humidity conditions , due to the improved protective properties of the barrier layer . The barrier layer comprising a non-crystalline matrix and a plurality of crystalline nanoparticles advantageously improves the reliability of the emitter particles , in particular of semiconductor nanocrystals , for use in downconversion applications . In this way, the conversion element can maintain its conversion ef ficiency over a longer time compared to conversion elements comprising structures and / or arrangements having barrier layer without crystalline nanoparticles in a non-crystalline matrix .

[0067] According to at least one embodiment , the semiconductor chip is a micro-LED . Here and in the following, LED is an abbreviation for the term " light-emitting diode" . Micro-LEDs may have a width, a length, a thickness and / or a diameter smaller than or equal to 100 micrometers , in particular smaller than or equal to 70 micrometers , for example smaller than or equal to 50 micrometers . In particular, micro-LEDs , for example rectangular micro-LEDs , have an edge length, for instance in plan view of layers of a layer stack, of a luminous surface smaller than or equal to 70 micrometers , for example smaller than or equal to 50 micrometers . For example , the micro-LED is a light-emitting diode , wherein a growth substrate is removed, such that a thickness of the micro-LED is , for instance , between and including 0 . 5 micrometers and 10 micrometers . For example , the micro-LED is provided on a wafer having releasable retaining structures . The micro-LED can be detached from the wafer in a non-destructive manner .

[0068] According to at least one embodiment , the optoelectronic device is used in any application with uses semiconductor nanocrystal or phosphor donwnconversion such as in display applications and / or in general lighting applications . In particular, the optoelectronic device is used in indoor lighting, outdoor lighting, automotive lighting and display applications . Advantageous embodiments and developments of the structure , the arrangement , the method for producing a structure , the method for producing an arrangement , and the optoelectronic device will become apparent from the exemplary embodiments described below in conj unction with the figures .

[0069] In the figures :

[0070] Figures 1 and 3 each show a schematic illustration of a structure according to di f ferent exemplary embodiments ,

[0071] Figures 2 and 4 each show a schematic illustration of a method for producing a structure according to di f ferent exemplary embodiments ,

[0072] Figure 5 shows a schematic illustration of an arrangement according to an exemplary embodiment ,

[0073] Figures 6 to 8 each show a schematic illustration of a method for producing an arrangement according to di f ferent exemplary embodiments ,

[0074] Figure 9 shows a schematic illustration of an optoelectronic device according to an exemplary embodiment , and

[0075] Figure 10 shows infrared spectra of silica having di f ferent degrees of crystallinity .

[0076] In the exemplary embodiments and figures , similar or similarly acting constituent parts are provided with the same reference signs . The elements illustrated in the figures and their si ze relationships among one another should not be regarded as true to scale . Rather, individual elements may be represented with an exaggerated si ze for the sake of better representability and / or for the sake of better understanding .

[0077] The structure 1 shown in the exemplary embodiment of figure 1 is a discrete nanoparticle comprising an extension of at most 1000 nm along its largest dimension . The structure 1 comprises an emitter particle 2 . The emitter particle 2 is configured to convert a primary radiation into a secondary radiation . In particular, the emitter particle 2 is a phosphor particle comprising a phosphor material 21 or a semiconductor structure 22 comprising at least one semiconductor nanocrystal 221 .

[0078] A barrier layer 3 at least partially, in particular completely, surrounds the emitter particle 2 . The barrier layer 3 is a conformal coating of the emitter particle 2 . The barrier layer 3 comprises a non-crystalline matrix 31 and a plurality of crystalline nanoparticles 32 . The plurality of crystalline nanoparticles 32 surround the emitter particle 2 with the non-crystalline matrix 31 holding them together and filling in gaps , voids and / or interstices between the crystalline nanoparticles 32 .

[0079] In the barrier layer 3 , the non-crystalline matrix 31 forms a non-crystalline phase and the plurality of crystalline nanoparticles 32 form a crystalline phase . The presence of the mixed phase of non-crystalline matrix 31 and crystalline nanoparticles 32 in the barrier layer 3 can be determined through transmission electron microscopy ( TEM) and / or x-ray di f fraction (XRD) . The non-crystalline matrix 31 can be present in amorphous form or in densi fied form . The non-crystalline matrix 31 comprises or consists of a first material . The first material is at least one of silica, titania, zirconia, alumina, magnesium oxide , hafnia, barium oxide , bismuth oxide , tin oxide , or mixed oxides . For example , the non-crystalline matrix 31 comprises or consists of silica .

[0080] The plurality of crystalline nanoparticles 32 are present in crystalline form . The plurality of crystalline nanoparticles 32 forms a random close packing in the barrier layer 3 . Each crystalline nanoparticles 32 has a diameter of at least 3 nm or 4 nm and of at most 500 nm . In particular, the plurality of crystalline nanoparticles 32 has a monodispersity of at most 10 % . For example , the crystalline nanoparticles have an average diameter of 10 nm or 20 nm . Alternatively, the crystalline nanoparticles can have an average diameter of 150 nm with a 10 % monodispersity .

[0081] The plurality of crystalline nanoparticles 32 comprises or consists of the first material . In this instance , the noncrystalline matrix 31 and the plurality of crystalline nanoparticles 32 comprise or consist of the same material , for example , silica .

[0082] Alternatively, the plurality of crystalline nanoparticles comprises or consists of a second material di f ferent from the first material . In particular, the second material is a metal oxide such as silica, zirconia, and hafnia, a metal sul fide such as zinc sul fide , or a metal such as gold .

[0083] The structure 1 according to the exemplary embodiment of figure 1 can be produced by the method shown in figure 2 : An emitter particle 2 , for example a phosphor material 21 or a semiconductor structure 22 , is provided . Subsequently, the emitter particle 2 is surrounded with a barrier layer 3 comprising a non-crystalline matrix 31 and a plurality of crystalline nanoparticles 32 .

[0084] For example , crystalline nanoparticles 32 are commercially available or can be formed prior to surrounding the emitter particle 2 with the barrier layer 3 to customi ze the si ze and the si ze distribution of the plurality of crystalline nanoparticles 32 as desired and to tailor them to speci fic applications . To incorporate the crystalline nanoparticles 32 into the non-crystalline matrix 31 , a surface of the crystalline nanoparticles 32 might need to be functionali zed, for example through treatment by acid such as sul furic acid .

[0085] In the method steps of surrounding the emitter particle 2 with the barrier layer 3 , the non-crystalline matrix 31 is grown from a precursor of the non-crystalline matrix 31 on a surface of the emitter particle 2 and the plurality of crystalline nanoparticles 32 is added into the growing layer of non-crystalline matrix 31 . For example , the barrier layer 3 is produced in a reverse micelle reaction or via Stober growth .

[0086] The precursor of the non-crystalline matrix 31 can bind the plurality of crystalline nanoparticles 32 together in networks that surround the emitter particle 2 . The reaction of incorporating the crystalline nanoparticles 32 can be driven by the chemical adhering of the , in particular functionali zed, crystalline surfaces of the crystalline nanoparticles 32 with one another or with the non-crystalline matrix 31 , for example by performing condensation reactions . Alternatively or additionally, the reaction can be polarity driven, and / or solubility driven .

[0087] For example , the non-crystalline matrix 31 and the plurality of crystalline nanoparticles 32 comprise silica . The precursor of the non-crystalline matrix 31 can be tetraethyl orthosilicate ( TEOS ) or tetramethyl orthosilicate ( TMOS ) . Non-crystalline silica shells are built up through precursors such as TEOS or TMOS by condensing neighboring Si-O-H moieties to yield Si-O-Si in a condensation reaction . Crystalline silica nanoparticles can be incorporated by having a layer of silicon hydroxide on the surface to be able to integrate into the TEOS network or TMOS network . This can be achieved in a number of ways :

[0088] 1 ) having a large-enough reverse micelle for silica growth may allow crystalline nanoparticles 32 to be added,

[0089] 2 ) making use of hydroxyl groups naturally existing on the surface of the crystalline nanoparticles 32 ,

[0090] 3 ) functionali zing the surface of the crystalline nanoparticles 32 to gain a hydroxide-rich surface through any number of routes including through treatment by acid such as sul furic acid .

[0091] After surrounding the emitter particle 2 with the barrier layer 3 , the non-crystalline matrix 31 can be densi fied to some extent through chemical treatment , heat treatment or by exposing to UV light . For example , a temperature of at most 250 ° C, for example of 120 ° C, can be applied to the barrier layer 3 .

[0092] The structure 1 shown in the exemplary embodiment of figure 3 corresponds substantially to the structure 1 of the exemplary embodiment shown in figure 1 . In the exemplary embodiment shown in figure 3 , the emitter particle 2 is a semiconductor structure 22 comprising a cluster 223 of a plurality of semiconductor nanocrystals 221 . In the exemplary embodiment in figure 3 , each semiconductor nanocrystal 221 is individually surrounded by an encapsulation layer 222 of , for example , silica . The cluster 223 can be an aggregate or an agglomerate of the plurality of semiconductor nanocrystals 221 .

[0093] The structure 1 according to the exemplary embodiment of figure 3 can be produced by the method shown in figure 4 : A plurality of semiconductor nanocrystals 221 individually surrounded with an encapsulation layer 222 is provided . A cluster 223 of the plurality of semiconductor nanocrystals 221 with the encapsulation layers 222 is formed, for example , by aggregating or agglomerating . The cluster 223 is a semiconductor structure 22 . Subsequently, the cluster 223 is surrounded with a barrier layer 3 as described above in conj unction with figure 2 .

[0094] The arrangement 10 shown in the exemplary embodiment in figure 5 is a discrete nanoparticle comprising an extension of at most 50000 nm, for example of 200 nm or 300 nm, along its largest dimension . The arrangement 10 comprises a cluster 11 of a plurality of structures 1 described herein . The cluster 11 can be an aggregate or an agglomerate of the plurality of structures 1 . The cluster 11 is surrounded with a barrier layer 3 . The barrier layer 3 in the arrangement 10 is a barrier layer 3 as described above in conj unction with the structure 1 .

[0095] The arrangement 10 comprises a plurality of barrier layers 3 as each structure 1 in the cluster 11 comprises a barrier layer 3 and a barrier layer 3 surrounds the cluster 11 . The barrier layers 3 in the arrangement 10 can have an identical , a similar or a di f ferent composition regarding materials of the non-crystalline matrix 31 and the crystalline nanoparticles 32 as well as si zes and si ze distributions of the crystalline nanoparticles 32 . For example , the barrier layers 3 can have similar or mixed si zes of crystalline nanoparticles 32 .

[0096] The arrangement 10 according to the exemplary embodiment of figure 5 can be produced by the method shown in figure 6 : A plurality of structures 1 described herein is provided . The structures 1 are starting materials 12 . A cluster 11 of the plurality of structures 1 is formed, for example , by aggregating or agglomerating . Subsequently, the cluster 11 is surrounded with a barrier layer 3 as described above in conj unction with figure 2 . The product 13 produced with this method sequence can be the arrangement 10 .

[0097] Alternatively, the product 13 can be an intermediate product that can be used as a starting material 12 for further reactions , in particular for repeating the method sequence described in conj unction with figure 6 .

[0098] Figure 7 shows the method sequence that can be performed subsequent to the method sequence shown in figure 6 . The method sequence shown in figure 7 can be repeated multiple times , for example up to thousands of times . The method sequence shown in figure 7 corresponds essentially to the method sequence shown in figure 6 . In contrast to figure 6 , figure 7 shows a more general version of the method sequence starting not with the structure 1 but with a starting material 12 . The starting material 12 can be the product 13 produced in the preceding method sequence , for example in the method sequence shown in figure 6 . In other words , the product 13 produced in the preceding method sequence is the starting material 12 for the subsequent method sequence .

[0099] Figure 8 schematically shows the method for producing an arrangement 10 according to figures 6 and 7 . The method for producing an arrangement 10 is a cycle of a plurality of method sequences each comprising method steps S I , S2 , and S3 . The method sequence can be performed once or the cycle can be repeated multiple times .

[0100] In method step S I , a plurality of starting materials 12 is provided . In the first method sequence of the method for producing an arrangement 10 , the starting material 12 is a structure 1 described herein . In any subsequent method sequences , the starting material 12 is the product 13 produced in the preceding method sequence .

[0101] In method step S2 , a cluster 11 of the plurality of starting materials 12 is formed .

[0102] In method step S3 , the cluster 11 is surrounded with a barrier layer 3 thereby forming product 13 . Product 13 can be the arrangement 10 produced with the method for producing an arrangement . Alternatively, product 13 is provided as the starting material 12 in method step S I of the subsequent method sequence .

[0103] Figure 9 shows a schematic illustration of an optoelectronic device 100 described herein according to a first exemplary embodiment . The optoelectronic device comprises a semiconductor chip 101 configured to emit a primary radiation of a first wavelength range . The semiconductor chip can be a micro-LED . For example , the first wavelength range is in the blue spectral region .

[0104] A conversion element 102 is arranged on a radiation exit surface of the semiconductor chip 101 . The conversion element 102 can be arranged directly on the radiation exit surface or in a distance to the radiation exit surface . The conversion element 102 can be in the form of a layer or a casting . The conversion element 102 converts at least a part of the primary radiation into secondary radiation of a second wavelength range . The conversion element comprises or consists of at least one structure 1 and / or at least one arrangement 10 described herein .

[0105] Figure 10 shows infrared spectra of silica having di f ferent degrees of crystallinity . The transmittance T in % is plotted against the wavenumber v in cm-1. Curves 10- 1 and 10-2 show infrared spectra of structures comprising a semiconductor structure surrounded with a barrier layer of silica . The semiconductor structures both comprise a core-shell-shell structure of CdSe / CdS / ZnS . In both instances , the barrier layers were grown via a sol-gel process . The structures of curve 10- 1 were dried at 120 ° C for 24 h and the structures of curve 10-2 were dried at 120 ° C for 48 h . By drying for 24 h, an amorphous silica barrier layer is produced . By drying for 48 h instead of only 24 h, an amorphous silica barrier layer is produced and subsequently densi fied . This can be seen in the infrared spectra in the intensity of the IR-active band at 1080 cm-1. This band is characteristic for the Si-O-Si stretch . Accordingly, the intensity of this band increases with increasing number of Si-O-Si units in the barrier layer . For the structure having the densi fied barrier layer, the intensity of this band is increased ( curve 10-2 ) relative to the intensity of the band of the structure having an amorphous barrier layer ( curve 10- 1 ) . Thus , the densi fied barrier layer comprises a higher number of Si-O-Si units than the amorphous barrier layer and, therefore , a higher degree of crystallinity .

[0106] Curve 10-3 shows the infrared spectrum of crystalline silica nanoparticles . Crystalline silica nanoparticles are essentially built up from Si-O-Si units and, therefore , the intensity of the band at 1080 cm-1is further increased relative to the curves 10- 1 and 10-2 . Further, curve 10-3 shows a sharp doublet at 800 cm-1and 780 cm-1that is characteristic for crystalline silica . This doublet is not present in both infrared spectra of curves 10- 1 and 10-2 as both the amorphous barrier layer and the densi fied barrier layer are formed from non-crystalline silica . The 810- 800 cm-1absorption of amorphous silica is broader and weaker than the 800 cm-1region bands of crystalline silica . Further, crystalline silica has an IR-active band at 695 cm-1( curve 10-3 ) that is not present for amorphous and densi fied silica ( curves 10- 1 and 10-2 ) .

[0107] The features and exemplary embodiments described in connection with the figures can be combined with each other according to further exemplary embodiments , even i f not all combinations are explicitly described . Furthermore , the exemplary embodiments described in connection with the figures may have alternative or additional features as described in the general part . This patent application claims the priority of provisional US patent application 63 / 625 , 135 , the disclosure content of which is hereby incorporated by reference . The invention is not restricted to the exemplary embodiments by the description on the basis of said exemplary embodiments . Rather, the invention encompasses any new feature and also any combination of features , which in particular comprises any combination of features in the patent claims and any combination of features in the exemplary embodiments , even i f this feature or this combination itsel f is not explicitly speci fied in the patent claims or exemplary embodiments .

[0108] References

[0109] 1 structure

[0110] 2 emitter particle

[0111] 21 phosphor material

[0112] 22 semiconductor structure

[0113] 221 semiconductor nanocrystal

[0114] 222 encapsulation layer

[0115] 223 cluster

[0116] 3 barrier layer

[0117] 31 non-crystalline matrix

[0118] 32 crystalline nanoparticle

[0119] 33 gap, void and / or interstice

[0120] 10 arrangement

[0121] 11 cluster

[0122] 12 starting material

[0123] 13 product

[0124] 100 optoelectronic device

[0125] 101 semiconductor chip

[0126] 102 conversion element

[0127] 51 method step

[0128] 52 method step

[0129] 53 method step

[0130] 10- 1 curve

[0131] 10-2 curve

[0132] 10-3 curve

Claims

Claims1. Structure (1) comprising- an emitter particle (2) configured to convert a primary radiation into a secondary radiation, and- a barrier layer (3) at least partially surrounding the emitter particle (2) , wherein the barrier layer (3) comprises a non-crystalline matrix (31) and a plurality of crystalline nanoparticles (32) .

2. Structure (1) according to the preceding claim, wherein the structure (1) is a discrete nanoparticle.

3. Structure (1) according to at least one of the preceding claims , wherein the structure (1) comprises an extension of at most 1000 nm along its largest dimension.

4. Structure (1) according to at least one of the preceding claims , wherein the barrier layer (3) forms a discrete layer around the emitter particle (2) .

5. Structure (1) according to at least one of the preceding claims , wherein the plurality of crystalline nanoparticles (32) forms a random close packing in the barrier layer (3) .

6. Structure (1) according to the preceding claim, wherein the plurality of crystalline nanoparticles (32) is bonded together by the non-crystalline matrix (31) .

7. Structure (1) according to at least one of the preceding claims , wherein the non-crystalline matrix (31) fills gaps, voids, and / or interstices (33) between the plurality of crystalline nanoparticles (32) within the barrier layer (3) .

8. Structure (1) according to at least one of the preceding claims , wherein the non-crystalline matrix (31) comprises a first material, and wherein the plurality of crystalline nanoparticles (32) comprises the first material or a second material different from the first material.

9. Structure (1) according to at least one of the preceding claims , wherein the emitter particle (2) comprises a phosphor material (21) or a semiconductor structure (22) comprising at least one semiconductor nanocrystal (221) .

10. Structure (1) according to the preceding claim, wherein the semiconductor structure (22) comprises a cluster (223) of a plurality of semiconductor nanocrystals (221) .

11. Arrangement (10) comprising- a cluster (11) of a plurality of structures (1) according to at least one of the preceding claims, and- a barrier layer (3) at least partially surrounding the cluster (11) , wherein the barrier layer (3) comprises a non-crystalline matrix (31) and a plurality of crystalline nanoparticles12. Method for producing a structure (1) comprising- providing an emitter particle (2) configured to convert a primary radiation into a secondary radiation, and- surrounding the emitter particle (2) at least partially with a barrier layer (3) , wherein the barrier layer (3) comprises a non-crystalline matrix (31) and a plurality of crystalline nanoparticles (32) .

13. Method according to the preceding claim, wherein, prior to surrounding the structure (2) at least partially with the barrier layer (3) , the plurality of crystalline nanoparticles (32) is formed.

14. Method according to at least one of the claims 12 or 13, wherein, prior to surrounding the structure (2) at least partially with the barrier layer (3) , a surface of the plurality of crystalline nanoparticles (32) is functionalized.

15. Method according to at least one of the claims 12 to 14, wherein, during surrounding the structure (2) at least partially with the barrier layer (3) , the plurality of crystalline nanoparticles (32) is added to a precursor of the non-crystalline matrix (31) .

16. Method according to at least one of the claims 12 to 15, wherein, after surrounding the structure (2) at least partially with the barrier layer (3) , the non-crystalline matrix (31) is densified.

17. Method for producing an arrangement (10) , comprising- performing the following method sequence:providing a plurality of starting materials (12) , wherein the starting material (12) is a structure (1) according to at least one of the claims 1 to 10 or a structure (1) produced by the method according to at least one of the claims 12 to 16, forming a cluster (11) of the plurality of starting materials ( 12 ) , surrounding the cluster (11) at least partially with a barrier layer (3) to form a product (13) , wherein the barrier layer (3) comprises a non-crystalline matrix (31) and a plurality of crystalline nanoparticles (32) .

18. Method according to the preceding claim, further comprising repeating the method sequence, wherein the product (13) is used as the starting material (12) .

19. An optoelectronic device (100) comprising: a semiconductor chip (101) configured to emit a primary radiation; a conversion element (102) configured to convert at least a part of the primary radiation into a secondary radiation; wherein the conversion element (102) comprises or consists of at least one structure (1) according to at least one of the claim 1 to 10, and / or wherein the conversion element (102) comprises or consists of at least one arrangement (10) according to claim 11.

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