KR20230027288A - Phosphor particle coating - Google Patents

Abstract

The present invention provides a method for providing a luminescent particle (100) with a hybrid coating comprising (i) providing a luminescent core (102) comprising a primer layer (105) on the luminescent core (102); (ii) providing a main ALD coating layer 120 onto the primer layer 105 by application of a main atomic layer deposition process, wherein the main ALD coating layer 120 consists of two or more layers having different chemical compositions ( 1121), wherein in the main atomic layer deposition process the metal oxide precursor is a metal oxide including Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V. selected from the group of seed precursors; (iii) providing a main sol-gel coating layer 130 onto the main ALD-coating layer 120 by application of a main sol-gel coating process, wherein the main sol-gel coating layer 130 has multiple layers ( having a different chemical composition than at least one of the layers 1121 of 1120).

Description

Phosphor particle coating

<Cross Reference to Related Applications>

[0002] This application claims the benefit of U.S. Application Serial No. 16/915,422, filed on June 29, 2020 entitled "Phosphor Particle Coating", and European Application No. 20189538.0, filed on August 5, 2020 (titled "Phosphor Particle Coating"). : "Phosphor Particle Coating"), which applications are hereby incorporated by reference in their entirety.

<Field of Invention>

The present invention relates to a method for providing a coated light emitting material, such a light emitting material, and a lighting device for converting wavelengths incorporating such a light emitting material.

Coatings of luminescent materials are known in the art. WO2014128676, for example, describes coated luminescent particles, luminescent converter elements, light sources, luminaires, and methods of manufacturing coated luminescent particles. The coated luminescent particle includes a luminescent particle, a first coating layer and a second coating layer. The luminescent particle includes a luminescent material for absorbing light in a first spectral range and converting the absorbed light into light in a second spectral range. Luminescent materials are sensitive to water. The first coating layer forms a first barrier to water and comprises a metal oxide or nitride, phosphide, sulfide based coating. The second coating layer forms a second barrier to water and comprises a silicon based polymer or a continuous layer of one of the materials AlPO ₄ , SiO ₂ , Al ₂ O ₃ and LaPO ₄ . The first coating layer and the second coating layer are light transmissive. The first coating layer encapsulates the luminescent particles and the second coating layer encapsulates the luminescent particles with the first coating layer.

Moisture sensitive luminescent powder materials can be coated with a layer of amorphous or glassy material to reduce the rate of degradation by moisture attack. Coating deposits material onto particle surfaces by deposition from the gas phase (eg, chemical vapor deposition or atomic layer deposition (ALD) processes) or by reacting dissolved inorganic precursors in suspension (eg, by sol-gel processes). can be applied by

Atomic layer deposition can be a suitable method for depositing thin conformal coatings of various inorganic materials on powder particles. ALD layers can be very dense and conformal, and can be substantially impermeable to gases such as water vapor and oxygen.

The ALD process further creates multiple thin layers of different inorganic materials, each capable of providing physical properties (such as moisture resistance, light transmittance, stress resistance, elasticity, etc.) to each layer, which can be different for different (nano)layers. (Nano Laminate) can be deposited.

The sol-gel process may be suitable for providing (relatively) thicker layers that may provide mechanical protection to the material coated with the layer.

Known coated luminescent particles may exhibit one or more disadvantages, such as mechanical instability during processing of the luminescent particles, degradation as a result of high temperatures, degradation of the luminescent material due to moisture or eg solvents. In addition, many known coating processes also have one or more disadvantages, such as agglomeration, reduction of the quantum efficiency of the coated light emitting material (versus uncoated material), non-conformal coatings.

It seems that the properties of the luminescent materials alone may not be sufficient with the sol-gel coating process. In addition, moisture sensitive luminescent particles comprising only an ALD coating may also not be durable when exposed to mechanical stress. Additionally, moisture sensitive luminescent particles with a sol-gel coating in combination with an ALD coating constructed on top of the sol-gel coating do not degrade due to moisture attack under relatively harsh conditions such as 90% relative humidity and temperatures up to 60°C. It appears possible to provide luminescent particles with reduced velocities. However, for higher temperatures such as may occur in high-power LED applications, for example flash and automotive applications, alternative coating structures may be desirable. Additionally, ALD layers appear to exhibit an intrinsic (tensile) stress that can increase with increasing layer thickness. ALD coatings may preferably be provided as thin layers. However, it appears that deposition of particularly thin ALD layers can be sensitive to surface contamination. Pinholes or other irregularities in the (thin) ALD layer may result due to possible contamination on the surface of the particle to be coated.

Accordingly, one aspect of the present invention is to provide an alternative coating process that preferably further at least partially eliminates one or more of the aforementioned drawbacks. A further aspect of the present invention is to provide an alternative phosphor, which preferably further at least partially avoids one or more of the aforementioned drawbacks. In yet a further aspect, the present invention preferably further provides a lighting device comprising a light emitting material that at least partially eliminates one or more of the aforementioned drawbacks.

The present invention may aim to overcome or improve at least one of the disadvantages of the prior art, or to provide a useful alternative.

Among other things, the present invention proposes in embodiments a coating structure comprising at least two layers, in particular at least three layers, constructed around a light emitting core. Different layers may be selected from those having different functions. The coating structure may include, inter alia, a primer layer, a coating layer provided by atomic layer deposition ("ALD coating layer"), and a coating layer provided by a sol-gel (deposition) process ("sol-gel coating layer"). . A primer layer can facilitate good adhesion between surfaces and can facilitate the deposition of thin ALD coating layers. The ALD coating layer can shield the light emitting core from undesirable gases such as water vapor and oxygen or additional chemicals. A sol-gel coating can provide mechanical protection to the light emitting core and ALD coating layer.

Therefore, herein, a coating layer is deposited on the primer layer (on the surface of the light emitting core) by application of an ALD process, and a sol-gel layer is subsequently deposited by application of a sol-gel type process to obtain a uniformly coated coating layer. A hybrid coating method for a luminescent powder material is provided, comprising the steps of obtaining luminescent particles. A luminescent particle equipped with a hybrid coating can be provided by the above method.

Accordingly, in a first aspect, the present invention provides a method for providing a luminescent particle with a hybrid coating. In embodiments, the method may inter alia include (i) a light emitting core ("core "providing (stages of). The method further comprises (ii) providing a (main) atomic layer deposition coating layer ("(main) ALD coating layer" or "(main) ALD coating" or "(main) ALD layer") onto the primer layer. includes A (main) ALD-coating layer is provided in embodiments particularly over a primer layer comprising a luminescent core. The method further comprises (iii) providing a (main) sol-gel coating layer ("(main) sol-gel coating" or "(main) sol-gel layer") onto the (main) ALD coating layer. include Additionally, a (main) ALD coating layer may be provided onto the primer layer by application of a (main) atomic layer deposition process ("(main) ALD process"). Additionally, in specific embodiments, the (main) ALD coating layer can include a multilayer (or “laminate”) with two or more layers having different chemical compositions. In further specific embodiments, in the (main) atomic layer deposition process, the metal oxide precursor comprises Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V (and optionally Si) It is selected from the group of metal oxide precursors. The (main) sol-gel coating layer is in particular provided onto the (main) ALD coating layer by application of a (main) sol-gel coating process. In further embodiments, the main sol-gel coating layer can have a different chemical composition than one or more of the multi-layered layers.

In a still further aspect, the present invention also provides a luminescent material comprising luminescent particles obtained by such a method. In particular, the present invention provides, in yet a further aspect, a luminescent material comprising luminescent particles, wherein the luminescent particles are as a primer layer on a luminescent core, in particular wherein the primer layer has a thickness of 0.1-10 nm, in particular 0.1-7 nm, a primer layer having a chemical composition different from that of the core and having a primer layer thickness (d1) in the range of, for example, 0.1-5 nm or 0.1-4 nm; A (main) ALD (ie atomic layer deposition) coating layer, especially comprising a multilayer with two or more layers having different chemical compositions, wherein in embodiments the (main) ALD coating is 5-250 nm, such as 5 have a (main) ALD coating layer thickness (d2) in the range of -100 nm, in particular 5-50 nm, such as in particular 10-50 nm, and even more particularly 20-50 nm, in particular wherein the multilayers are Al, Zn, Hf, Ta , Zr, Ti, Sn, Nb, Y, Ga and V (and optionally Si), wherein at least one of the two or more layers of the multilayer comprises a chemical composition of the primer layer and a (main) ALD coating layer having different chemical compositions; and further in embodiments in particular as a (main) sol-gel coating layer, wherein in embodiments the (main) sol-gel coating is 50-700 nm, such as 50-600 nm, in particular 75-500 nm, such as in particular and a (main) sol-gel coating layer having a (main) sol-gel coating layer thickness (d3) in the range of 100-500 nm. In further embodiments, the (main) sol-gel coating layer has a different chemical composition from the (main) ALD coating layer, in particular from one or more of the two or more layers of the multilayer. Further, in particular, the (main) ALD coating layer is disposed between the primer layer and the (main) sol-gel layer.

The present invention can provide luminescent particles and a luminescent material exhibiting a significantly reduced decomposition rate as a result of moisture attack, that is, a luminescent material comprising these (hybrid coated) particles. The coating of the luminescent particles can exhibit improved moisture barrier properties. The coating is additionally suitable for high-power products, for example flash and automotive applications that impose high stress conditions (eg operating temperature up to 85° C. at high relative humidity (greater than 80% relative humidity)). It can provide improved chemical and mechanical stability allowing the aggregation of luminescent particles (phosphors), in particular moisture sensitive luminescent particles (phosphors). With such a luminescent material, it is superior to non-coated or non-hybrid coated luminescent particles and has a very high stability to water and/or (moist) air and equal to virgin (non-coated) luminescent material. A relatively stable light emitting material with quantum efficiencies at or close to it is provided.

The present invention provides, in particular embodiments, a method for providing a luminescent particle with a hybrid coating comprising: (i) providing a luminescent core comprising a primer layer on the luminescent core; (ii) providing a main ALD coating layer over the primer layer by application of a main atomic layer deposition process, wherein the main ALD coating layer comprises a multilayer with two or more layers having different chemical compositions, wherein the main atomic layer deposition process is wherein the metal oxide precursor in the layer deposition process is selected from the group of metal oxide precursors comprising Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V (and optionally Si) ; (iii) providing a main sol-gel coating layer over the main ALD-coating layer by application of a main sol-gel coating process, wherein the main sol-gel coating layer has a different chemical composition than one or more of the layers of the multilayer. It is possible to provide a method comprising the step of. In particular, in the main atomic layer deposition process, the metal oxide precursor is a metal oxide of metals selected from the group consisting of Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V (and optionally Si) It is selected from the group of precursors.

Thus, the starting material is a particulate light emitting material or a micronized light emitting material. Additionally, in particular the luminescent core is a particulate core or a particulated luminescent (core) material. The core may be essentially a (virgin) luminescent particle/core, ie a non-coated/untreated luminescent particle. The luminescent particles (particularly the core(s)) of the particulate luminescent material are coated as described herein. The terms “luminescent particles”, “luminescent core” and similar terms indicate that the particles and/or cores emit light, in particular under excitation with UV and/or blue radiation (light source radiation, see below). In this application, the term "luminescent particle" may also be used to refer to a "luminescent core". In addition, luminescent particles that are also coated herein may be referred to as “luminescent particles”. Whether the term “luminescent particle” refers to an uncoated core, or for example it refers to a luminescent particle comprising a hybrid coating, or a luminescent particle comprising only one or more layers of a hybrid coating, will depend on the context. It will be clear.

The light-emitting core (before applying the ALD coating process) particularly includes a primer layer on (a surface of) the light-emitting core. In the present application, a luminescent core comprising a primer layer (on the luminescent core) is also referred to as "a primer layer comprising a luminescent core". In embodiments, the virgin (core) material (already) includes a primer layer. In embodiments, for example, the core can include an oxide-containing surface. In further embodiments, a primer layer may be applied to the virgin (core) material, in particular using the method of the present invention. Accordingly, in further embodiments, the method may include providing a primer layer onto the core (to provide a luminescent core comprising a primer layer on the luminescent core) (see further below).

The primer layer is not necessarily entirely conformal with the core. The primer layer can be especially evenly distributed over (the surface of) the light emitting core. However, the primer layer may not cover all of the surface of the core in embodiments. The primer layer may in embodiments cover the core over at least 50%, particularly at least 75%, such as at least 90%, or particularly at least 95% or even more particularly at least 99% of the surface of the core (see further below). ). The primer layer may be specifically configured to facilitate deposition of the main ALD coating layer. The primer layer can function as a nucleation layer or seed layer for the main ALD coating layer.

The main ALD coating layer is provided over the primer layer. Thus, in embodiments, the ALD coating layer can contact the surface of the light emitting core at first locations of the light emitting core that includes the primer layer, and the ALD coating layer can contact the primer layer at additional locations. . The main ALD coating layer may optionally include multiple layers. However, the multiple layers of the main ALD coating layer are all ALD layers. Accordingly, this layer is denoted as the (main) ALD (coating) layer (and thus optionally including ALD multilayers). In particular the main ALD coating layer comprises a multilayer with two or more layers (with different chemical compositions), see also below. The main ALD coating layer in particular comprises at least one aluminum oxide (in particular Al ₂ O ₃ ) coating layer.

Likewise, the main sol-gel coating layer may optionally include multiple layers. However, the (multi-)layers of the main sol-gel coating layer are all sol-gel layers. Accordingly, this coating layer is also referred to herein as the (main) sol-gel (coating) layer (and thus optionally comprising sol-gel multilayers). Additionally, in particular the main sol-gel coating layer is provided on the main ALD coating layer without intermediate layers. The main sol-gel coating layer especially comprises silicon oxide (especially SiO ₂ ). Examples of multilayers are for example SiO ₂ -Al ₂ O _3-x (OH) _2x (sol-gel) multilayers (where 0≤x≤3), such as SiO ₂ and Al ₂ O _3-x (OH) _2x (Where 0≤x≤3) may comprise a stack of three or more (sol-gel) layers alternating. Optionally a further coating layer may be provided on top of the main sol-gel coating layer (see further below).

In particular, both the main ALD coating layer and the main sol-gel coating layer independently comprise metal oxides, but optionally also hydroxides may be included in one or more of these layers. Additionally, independently the main ALD coating layer and the main sol-gel coating layer may include mixed oxide layers. Additionally, the coating layers do not necessarily have to be fully stoichiometric oxides as is known in the art.

In embodiments, the primer layer (also) includes a sol-gel coating layer (provided by application of a sol-gel process). Herein, such a sol-gel coating layer may be denoted as a primary sol-gel coating layer, in particular to distinguish it from the main sol-gel coating layer. The first sol-gel coating layer may, in embodiments, include metal oxides and optionally hydroxides as described herein with respect to the main sol-gel coating layer. Additionally, in particular, the first sol-gel coating layer may be provided as described in relation to the main sol-gel coating layer (see also below which further describes the sol-gel process). The first sol-gel coating layer may be provided as described (and may include a composition as described), in particular with respect to the main sol-gel coating.

The primer layer may (and) (additionally) include an oxide-containing layer in further embodiments. In specific embodiments, an oxide-containing layer is provided onto the light emitting core by application of a chemical cleaning process (see further below). A chemical cleaning process may in particular provide a layer resulting from the cleaning onto the light emitting core. Thus, in embodiments, the resulting wash layer includes an oxide-containing layer. The primer layer may in particular function as a nucleation layer or seed layer for the main ALD coating layer. However, the primer layer may be structurally different in various embodiments. As explained above, in embodiments, the primer layer comprises (at the surface of the light emitting core) an oxide-containing layer (or an oxide-rich layer), and in particular consists of it. In further embodiments, the primer layer comprises, in particular consists of, a wash result layer. In further embodiments, the primer layer comprises, in particular consists of, a first sol-gel coating layer. In further specific embodiments, the primer layer includes a wash result layer and a primary sol-layer.

In particular (if a chemical cleaning process is performed on the core), a first sol-gel coating layer is provided after the chemical cleaning process, in particular the first sol-gel coating is applied on the layer resulting from the cleaning (in particular the oxide-containing layer). can be provided. However, in such embodiments, the first sol-gel coating layer may contact the washing result layer at the first location of the light emitting core. The primary sol-gel coating may contact the surface of the light emitting core at different locations of the light emitting core. Thus, in embodiments, the primer layer comprises an oxide-containing layer and a first sol-gel layer, in particular wherein the oxide-containing layer is disposed on the surface of the core (and of the first sol-gel coating layer). at least partly disposed in the oxide-containing layer).

As described above, in embodiments, the locations of the core may not be covered by a primary layer (in particular, one or more of an oxide-containing layer and a primary sol-gel coating layer). Thus, in embodiments, the main ALD coating layer can be in contact with (provided to be in contact with) the primary sol-gel coating layer at some locations of the light emitting core, and the main ALD coating layer can be in contact with at some other locations of the light emitting particle. may be brought into contact with (provided to be in contact with) the surface of the core. In still further embodiments, the main ALD coating can (also) contact (provide to be in contact with) the washing result layer at some additional locations of the luminescent particle.

In general, the thickness of the primer layer is smaller than the thickness of the main sol-gel layer, in particular also smaller than the thickness of the main ALD coating layer. Additionally, in particular the main sol-gel coating layer thickness is generally greater than the ALD coating layer thickness. The primer layer thickness is in particular less than or equal to 10 nm, such as less than or equal to 7 nm, in particular less than or equal to 5 nm, and even more particularly less than or equal to 4 nm. The primer layer thickness may in embodiments be at least 0.1 nm, such as at least 0.2 nm, in particular at least 0.5 nm, such as in particular at least 1 nm. The first layer thickness can in particular be a result of the thickness of the first sol-gel coating layer. Thus, in particular the first sol-gel coating layer may be 10 nm or less, such as 7 nm or less, in particular 5 nm or less, such as 4 nm or less. The oxide-containing layer may be less than 1 nm thick in embodiments. In embodiments the primer layer has a primer layer thickness d1 in the range of 0.1-5 nm. In further embodiments, the primer layer comprises a first sol-gel layer provided by application of a first sol-gel coating process. The thickness of the main sol-gel coating layer can be at least 10 times, such as at least 50 times, in particular at least 100 times, thicker than the thickness of the first layer.

Additionally, in particular the main sol-gel coating layer thickness is generally greater than the main ALD coating layer thickness, such as at least 1.2 times (than the main ALD coating layer thickness), such as at least 1.5 times, such as at least 2 times greater, or Even at least 4 times or at least 5 times or at least 10 times larger.

In specific embodiments, the method of the present invention comprises (i) applying a primer layer, particularly 0.1-10 nm, particularly 0.1-7 nm, such as 0.1-5 nm, onto the core (to provide a primer layer comprising a light emitting core). or having a primer layer thickness (d1) in the range of 0.1-4 nm; (ii) 3-250 nm, such as 5-250 nm, in particular 5-100 nm, and more particularly 5-250 nm onto the primer layer (in particular onto the primer layer comprising the luminescent core) by application of a main atomic layer deposition process. providing a main ALD coating layer having a main ALD coating layer thickness (d2) in the range of -50 nm, such as in particular between 10-50 nm and even more particularly between 20-50 nm; and in particular (iii) a main sol-gel coating in the range of 50-700 nm, such as 50-600 nm, especially 75-500 nm, such as especially 100-500 nm, onto the main ALD coating layer by application of a main sol-gel process. providing a main sol-gel coating layer having a layer thickness d3.

In particular, the primer layer has a primer layer thickness d1 in the range of 0.1-10 nm, in particular 0.1-7 nm, such as 0.1-5 nm or 0.1-4 nm. Additionally, in particular the main ALD coating layer has a range of 3-250 nm, such as 5-250 nm, particularly 5-100 nm, more particularly 5-50 nm, such as particularly 10-50 nm, and more particularly 20-50 nm. It has a main ALD coating layer thickness (d2). In particular, the main sol-gel coating layer has a main sol-gel coating layer thickness d3 in the range of 50-700 nm, such as 50-600 nm, in particular 75-500 nm, such as in particular 100-500 nm.

Thus, as indicated above, the luminescent particle may in embodiments have a luminescent core, a primer layer having a primer layer thickness (d1) in the range of 0.1-10 nm, in particular 0.1-7 nm, such as 0.1-5 nm or 0.1-4 nm. , the main ALD coating layer thickness (d2) in the range of 3-250 nm, such as 5-250 nm, in particular 5-100 nm, more particularly 5-50 nm, such as in particular 10-50 nm, still more particularly 20-50 nm and a main sol-gel coating layer thickness (d3) in the range of 50-700 nm, such as 50-600 nm, in particular 75-500 nm, such as in particular 100-500 nm. contains a layer

In embodiments, the primer layer at least partially encapsulates the surface of the light emitting core. In further embodiments, the main ALD coating encapsulates the primer layer. In further embodiments the main sol-gel coating encapsulates the main ALD coating layer. In still further embodiments, an additional ALD coating layer encapsulates the main sol-gel coating layer (see below). Thus, the hybrid coating may include a main ALD coating layer and a main sol-gel coating layer, particularly a primer layer, a main ALD coating layer, and a main sol-gel coating layer. The primer layer is in particular disposed between the main ALD coating layer and the surface of the light emitting core. The main ALD coating layer is in particular disposed between the main sol-gel coating layer and the primer layer.

In still further embodiments, the luminescent particle can include an additional coating layer disposed on the main sol-gel coating layer. In further embodiments, the hybrid coating further comprises an additional coating layer disposed on the main-sol-gel coating layer. The additional coating layer may in particular include an additional ALD coating layer, in particular encapsulating the main sol-gel coating. Thus, in embodiments, the luminescent particle includes (additionally) an additional ALD coating layer disposed over the main sol-gel coating layer. The further ALD coating layer has a further ALD coating layer thickness (d4) in particular in the range of 1-100 nm, such as 5-75 nm, in particular 10-75 nm, such as in particular 10-50 nm. Additionally, in particular the further ALD coating layer has a chemical composition different from that of the main sol-gel coating layer.

Thus, in specific embodiments, the method comprises (iv) providing an additional ALD coating layer onto the main sol-gel coating by application of an additional atomic layer deposition process (particularly whereby additional ALD coated light emitting particles), in particular wherein the further ALD coating layer has a further ALD coating layer thickness (d4) in the range of 1-100 nm, such as 5-75 nm, in particular 10-75 nm, such as in particular 10-50 nm, In particular here the further ALD coating layer has a chemical composition different from that of the main sol-gel coating layer. Additional ALD coating layers may be provided by the ALD processes described herein, particularly with respect to the main ALD layer. Additional ALD layers may (also) include multiple layers. The further ALD layer may further comprise the composition (and/or (metal) oxides) described in particular in relation to the main ALD layer. In embodiments, the additional ALD coating layer comprises one or more oxides of one or more of Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V, and optionally Si.

The term "thickness" is used herein in reference to coatings and layers. The term relates in particular to the average thickness of the coating over the entire surface coated by each layer. For example, the primary layer may not completely cover the surface of the core, and the (local) thickness of the primer layer may be substantially zero at locations of the surface core. At other locations on the surface, the maximum (local) thickness of the primer layer may be 3 nm. Then, for example, the primer layer thickness can range from greater than 0 to less than 3 nm. Moreover, also if the (coating) layer completely covers the core or another coating layer, the local thickness may vary. In particular, for example, a sol-gel process may provide coating layers having a somewhat porous shape or may contain, for example, one or more small pinholes. Accordingly, the layer thicknesses described herein are in particular average layer thicknesses. However, in particular, in the case of at least the primer layer, the main sol gel coating layer, the main ALD coating layer and the additional ALD coating layer (if present), at least 50%, even more particularly at least 80% of the area of each layer is such an indicated layer have a thickness In particular, this indicates that under at least 50% of the area of such a layer, such a thickness will be found.

The luminescent core of interest can in principle comprise each type of (virgin) luminescent particle or particulate material. However, of particular interest are those types of luminescent particulate materials (particles) which may be less stable in air or water or humid environments, such as, for example, (oxo)sulfides, (oxo)nitrides, and the like. Thus, in embodiments the luminescent core (and the luminescent particle comprising the luminescent core) may include a nitride luminescent material, an oxonitride luminescent material, a halogenide luminescent material, an oxohalogenide luminescent material, a sulfide luminescent material and an iodine luminescent material. and at least one of sulfide light emitting materials. Additionally or alternatively, the luminescent core (luminescent particle) may comprise a selenide luminescent material. Thus, the term “luminescent core” (and also “luminescent particles”) may refer to a combination of particulate materials of different types of luminescent materials. The luminescent core may in embodiments specifically include a plurality of particulate luminescent materials/luminescent particles.

In a specific embodiment, the luminescent core (or the material of the luminescent core) is selected from the following groups of luminescent material systems: MLiAl ₃ N ₄ :Eu (M=Sr, Ba, Ca, Mg), MLi ₂ Al ₂ O ₂ N ₂ : Eu (M=Ba, Sr, Ca), M ₂ SiO ₄ :Eu (M=Ba, Sr, Ca), MSe _1-x S _x :Eu (M=Sr, Ca, Mg), MA ₂ S ₄ : Eu (M=Sr, Ca, A=Al, Ga), M ₂ SiF ₆ :Mn (M=Na, K, Rb), MSiAlN ₃ :Eu (M=Ca, Sr), M ₈ Mg(SiO ₄ ) ₄ Cl ₂ :Eu (M=Ca, Sr), M ₃ MgSi ₂ O ₈ :Eu (M=Sr, Ba, Ca), MSi ₂ O ₂ N ₂ :Eu (M=Ba, Sr, Ca), MLi ₃ SiO ₄ :Eu (M=Li, Na, K, Rb, Cs), M ₂ Si _5-x Al _x OxN _8-x :EU (M=Sr, Ca, Ba). However, other systems may also be of interest to be protected by hybrid coatings. Combinations of particles/particulate materials of two or more different light emitting materials may also be applied, for example a green or yellow light emitting material combined with a red light emitting material.

Terms such as "M=Sr, Ba, Ca, Mg" indicate that M includes one or more of Sr, Ba, Ca, and Mg, as is known in the art. For example, referring to MSiAlN ₃ :Eu (M=Ca, Sr), it may refer to, for example, CaSiAlN ₃ :Eu or SrSiAlN ₃ :Eu or Ca _0.8 Sr _0.2 SiAlN ₃ :Eu and the like. Additionally, the formula “MLiAl ₃ N ₄ :Eu (M=Sr, Ba, Ca, Mg)” is the same as the formula (Sr,Ba,Ca,Mg)LiAl ₃ N ₄ :Eu. Additionally, for the sake of clarity, for example, "wherein the luminescent material is (M1)Li _d Mg _a Al _b N ₄ :Eu (where 0≤a≤4; 0≤b≤4; 0≤ d≤4, and M1 includes at least one of the group consisting of Ca, Sr, and Ba; and (M ₂ )Li ₂ Al _2-z Si _z O _2-z N _2+z :Eu (where 0≤ z≤0.1, and M2 is selected from the group consisting of at least one of the groups consisting of Sr and Ba" when more than one group is represented by different elements, the formula "(M1)LiAl ₃ N ₄ :Eu (M1 = Sr, Ba, Ca)" and the like can be used. Additionally, M1, M2, etc. may also refer to one or more of (each) elements. In the example given above, for example M1 may be Sr or Ba or Ca in embodiments. In further embodiments M1 can be Sr and Ba or, for example, Sr and Ca, or a combination of Sr, Ba and Ca, and the like. Also, the elements may in particular be present in any ratio, for example 20% Sr, 20% Ca and 50% Ba, or 10% Ba and 90% Sr, etc. Likewise, this applies to inorganic light emitting materials of other chemical formulas indicated herein.

In further specific embodiments, the luminescent core may be selected from the group of luminescent material systems: M _1-xyz Z _z A _a B _b C _c D _d E _e N _4-n O _n :ES _x ,RE _y may be selected from the group consisting of M = Ca (calcium), Sr (strontium) and Ba (barium); Z is monovalent and is selected from the group consisting of Na (sodium), K (potassium) and Rb (rubidium); A=2 is selected from the group consisting of Mg (magnesium), Mn (manganese), Zn (zinc) and Cd (cadmium) (in particular, A=2 is Mg (magnesium), Mn (manganese) and Zn ( zinc), and more particularly divalent Mg (magnesium), Mn (manganese)); B=3 is selected from the group consisting of B (boron), Al (aluminum) and Ga (gallium); C=4 is selected from the group consisting of Si (silicon), Ge (germanium), Ti (titanium) and Hf (hafnium); D is selected from the group consisting of monovalent Li (lithium) and Cu (copper); E is selected from the group consisting of P (elemental phosphor), V (vanadium), Nb (niobium) and Ta (tantalum); ES=2 is selected from the group consisting of Eu (europium), Sm (samarium) and ytterbium, in particular divalent Eu and Sm; When RE=3, Ce (Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium), Eu (Europium), Gd (Gadolinium), Tb (Terbium), Dy (dysprosium), Ho (holmium), Er (erbium) and Tm (thulium); 0≤x≤0.2; 0≤y≤0.2; 0<x+y≤0.4;0≤z<1;0≤n≤0.5; 0≤a≤4 (eg 2≤a≤3); 0≤b≤4; 0≤c≤4; 0≤d≤4; 0≤e≤4; a+b+c+d+e=4; and 2a+3b+4c+d+5e=10-y-n+z. In particular, z≤0.9, such as z≤0.5. Additionally, in particular x+y+z≤0.2.

Equations a+b+c+d+e=4; and 2a+3b+4c+d+5e=10-y-n+z respectively determine the Z, A, B, C, D and E cations and O and N anions, respectively, in the lattice, whereby (also) Define the charge neutrality of the system. For example, charge cancellation is covered by the equation 2a+3b+4c+d+5e=10-y-n+z. It covers, for example, charge offset by reducing the O content or charge offset by replacing C cations with B cations or B cations with A cations, etc. For example: if x=0.01, y=0.02, n=0, a=3; 6+3b+4c=10-0.02; a+b+c=4: b=0.02, c=0.98.

As will be apparent to those skilled in the art, a, b, c, d, e, n, x, y, z are always greater than or equal to zero. a is the equation a+b+c+d+e=4; and 2a+3b+4c+d+5e=10-y-n+z, in principle b, c, d and e do not need to be further defined. However, for completeness, herein also 0&lt;b&lt;4;0≤c≤4;0≤d≤4; 0≤e≤4 is defined.

A system such as SrMg ₂ Ga ₂ N ₄ :Eu is assumed. Here a = 2, b = 2, c = d = e = y = z = n = 0. In such a system, 2+2+0+0+0=4 and 2*2+3*2+0+0+0=10-0-0+0=10. Therefore, both equations are obeyed. Assume that 0.5 O is introduced. A system with 0.5 O can be obtained, for example, when 0.5 Ga—N is replaced by 0.5 Mg—O (which is a charge neutral replacement). This would result in SrMg _2.5 Ga _1.5 N _3.5 O _0.5 :Eu. Here, for such a system, 2.5+1.5+0+0+0=4 and 2*2.5+3*1.5+0+0+0=10-0-0.5+0=9.5. Therefore, both equations are obeyed here as well.

As indicated above, in advantageous embodiments d>0 and/or z>0, in particular at least d>0. In particular, the phosphor contains at least lithium. In another embodiment, 2≤a≤3, and in particular also d=0, e=0 and z=0. In such a case, the phosphor is inter alia a+b+c=4; and 2a+3b+4c=10-y-n.

In a further specific embodiment that may be combined with the former embodiments, e=0. In yet a further specific embodiment that may be combined with the former embodiments, M is Ca and/or Sr.

Thus, in a specific embodiment, a phosphor has the formula M(Ca and/or Sr) _1-xy Mg _a Al _b Si _c N _4-n O _n :ES _x ,RE _y (I), where ES=2 is Eu (europium) or Sm (samarium) or Yb (ytterbium); When RE=3, Ce (Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium), Eu (Europium), Gd (Gadolinium), Tb (Terbium), Dy (dysprosium), Ho (holmium), Er (Erbium) and Tm (Thulium), wherein y/x<0.1, particularly <0.01, and n≤0.1, particularly <0.01, even more particularly <0.001, and even more particularly <0.0001. Thus, in this embodiment, substantially samarium and/or europium containing phosphors are described. For example, when divalent Eu is present, x=0.05, and for example, y1 for Pr may be 0.001 and y2 for Tb may be 0.001, resulting in y=y1+y2=0.002. In that case, y/x=0.04. Even more particularly, y=0. However, when Eu and Ce are applied as indicated elsewhere, the ratio y/x may be greater than 0.1.

The condition 0<x+y≤0.4 indicates that M can be substituted with ES and/or RE up to a total of 40%. The condition “0<x+y≤0.4” combined with x and y being between 0 and 0.2 indicates that at least one of ES and RE is present. Not necessarily both types exist. As indicated above, both ES and RE may each independently refer to one or more subspecies, e.g., ES refers to one or more of Sm and Eu and RE refers to Ce, Pr, Nd, Sm, Eu, Gd, refers to one or more of Tb, Dy, Ho, Er and Tm.

In particular, when europium is applied as divalent luminescent species or dopant (ie Eu ²⁺ ), the molar ratio between samarium and europium (Sm/Eu) is <0.1, especially <0.01, especially <0.001. The same applies when europium in combination with ytterbium is applied. When europium is applied as divalent luminescent species or dopant, the molar ratio between ytterbium and europium (Yb/Eu) is <0.1, especially <0.01, especially <0.001. If all three are applied together, the same molar ratio can be applied, ie, ((Sm+Yb)/Eu) is <0.1, especially <0.01, especially <0.001.

In particular, x is in the range of 0.001-0.2 (ie 0.001≤x≤0.2), such as 0.002-0.2, such as 0.005-0.1, especially 0.005-0.08. Particularly in the case of divalent europium in the systems described herein, the mole percentage may range from 0.1-5% (where 0.001 ≤ x ≤ 0.05), such as 0.2-5%, such as 0.5-2%. For other luminescent ions, x may (although not necessarily) be greater than or equal to 1% (where x is greater than or equal to 0.01) in embodiments.

In a specific embodiment, the phosphor is (Sr,Ca)Mg ₃ SiN ₄ :Eu, (Sr,Ca)Mg ₂ Al ₂ N ₄ :Eu, (Sr,Ca)LiAl ₃ N ₄ :Eu and (Sr,Ca) Li _d Mg _a Al _b N ₄ :Eu, wherein a, b and d are as defined above.

As also indicated herein, the notation "(Sr,Ca)", and similar notations for other elements, indicate that the M-sites are occupied by Sr and/or Ca cations (or other elements, respectively).

In further specific embodiments the phosphor is _{Ba.95 Sr.05} Mg ₂ Ga ₂ N ₄ :Eu, BaMg ₂ Ga ₂ N ₄ :Eu, SrMg ₃ SiN ₄ :Eu, SrMg ₂ Al ₂ N ₄ :Eu, SrMg ₂ Ga ₂ N ₄ :Eu, BaMg ₃ SiN ₄ :Eu, CaLiAl ₃ N ₄ :Eu, SrLiAl ₃ N ₄ :Eu, CaLi _0.5 MgAl _2.5 N ₄ :Eu and SrLi _0.5 MgAl _2.5 N ₄ :Eu is chosen Further (non-limiting) examples for such phosphors are for example (Sr _0.8 Ca _0.2 ) _0.995 LiAl _2.91 Mg _0.09 N _3.91 O _0.09 :Eu _0.005 ; (Sr _0.9 Ca _0.1 ) _0.905 Na _0.09 LiAl ₃ N _3.91 O _0.09 : Eu _0.005 ; (Sr _0.8 Ca _0.03 Ba _0.17 ) _0.989 LiAl _2.99 Mg _0.01 N ₄ :Ce _0.01 , Eu _0.001 ; Ca _0.995 LiAl _2.995 Mg _0.005 N _3.995 O _0.005 :Yb _0.005 (YB(II)); Na _0.995 MgAl ₃ N ₄ :Eu _0.005 ; Na _0.895 Ca _0.1 Mg _0.9 Li _0.1 Al ₃ N ₄ :Eu _0.005 ; Sr _0.99 LiMgAlSiN ₄ : Eu _0.01 ; Ca _0.995 LiAl _2.955 Mg _0.045 N _3.96 O _0.04 :Ce _0.005 ; (Sr _0.9 Ca _0.1 ) _0.998 Al _1.99 Mg _2.01 N _3.99 O _0.01 : Eu _0.002 ; (Sr _0.9 Ba _0.1 ) _0.998 Al _1.99 Mg _2.01 N _3.99 O _0.01 : Eu _0.002 .

In further specific embodiments, the phosphor is selected from the group consisting of (Sr,Ca)Mg ₃ SiN ₄ :Eu and (Sr,Ca)Mg ₂ Al ₂ N ₄ :Eu. In another specific embodiment, the phosphor is Ba _0.95 Sr _0.05 Mg ₂ Ga ₂ N ₄ :Eu, BaMg ₂ Ga ₂ N ₄ :Eu, SrMg ₃ SiN ₄ :Eu, SrMg ₂ Al ₂ N ₄ :Eu, SrMg ₂ Ga ₂ N ₄ :Eu and BaMg ₃ SiN ₄ :Eu. In particular, these phosphors, and even more particularly (Sr,Ca)Mg ₃ SiN ₄ :Eu and (Sr,Ca)Mg ₂ Al ₂ N ₄ :Eu, have good luminescent properties, above all in terms of the distribution and spectral position of the luminescence. may be phosphors having

In further specific embodiments the phosphor, in particular the luminescent material, is selected from the group consisting of (Sr,Ca)LiAl ₃ N ₄ :Eu and (Sr,Ca,Ba)Li _d Mg _a Al _b N ₄ :Eu; ≤a≤4; 0≤b≤4; 0≤d≤4; and a+b+d=4 and 2a+3b+d=10. In another specific embodiment, the phosphor is selected from the class of (Sr,Ba)Li ₂ Al _2-z SizO _2-z N _2+z :Eu, 0≤z≤0.1.

The luminescent material is in embodiments selected from the group SrLiAl ₃ N ₄ :Eu. The light emitting material may include, for example, SrLiAl ₃ N ₄ :Eu having an Eu doping concentration in the range of 0.1-5%, particularly 0.1-2%, eg 0.2-1.2% relative to Sr.

In further specific embodiments, the phosphor/luminescent core (luminescent material) comprises SrLi ₂ Al _1.995 Si _0.005 O _1.995 with a Eu doping concentration in the range of 0.1-5%, in particular 0.1-2%, 0.2-1.5% relative to Sr. N _2.005 : Contains Eu ²⁺ .

The phosphor complies with 0≤x≤0.2, y/x<0.1, M contains at least Sr, z≤0.1, a≤0.4, 2.5≤b≤3.5, B contains at least Al, and c≤ Of particular interest are phosphors in which 0.4, 0.5 ≤ d ≤ 1.5, D contains at least Li, e ≤ 0.4, n ≤ 0.1 and ES contains at least Eu. In particular, y+z≤0.1. Additionally, in particular x+y+z≤0.2. Additionally, in particular a is close to or equal to zero. Additionally, in particular b is about 3. Additionally, in particular c is close to or equal to zero. Additionally, in particular d is about 1. Additionally, in particular e is close to or equal to zero. Additionally, in particular n is close to or equal to zero. Additionally, in particular y is close to or equal to zero. z+d>0 in terms of quantum efficiency and hydrolytic stability, ie at least one of Na, K, Rb, Li and Cu(I), especially those in which at least Li is available, such as (Sr,Ca)LiAl ₃ N ₄ :Eu and (Sr,Ca)Li _d Mg _a Al _b N ₄ :Eu (a, b, d as defined above) are particularly preferred systems. In further specific embodiments the phosphor is selected from the group consisting of CaLiAl ₃ N ₄ :Eu, SrLiAl ₃ N ₄ :Eu, CaLi _0.5 MgAl _2.5 N ₄ :Eu and SrLi _0.5 MgAl _2.5 N ₄ :Eu. Of particular interest is (Sr,Ca,Ba)(Li,Cu)(Al,B,Ga) ₃ N ₄ :Eu, which contains at least Sr as the M ion, at least Al as the B ion, and at least Li as the D ion. are additional phosphors that are subject to

In embodiments, the phosphor (luminescent core) is (M1)Li _d Mg _a Al _b N ₄ :Eu, where 0≤a≤4; 0≤b≤4; 0≤d≤4, and M1 is Ca, Sr and Ba (selected elements) wherein a+b+d=4 and 2a+3b+d=10; and (M2)Li ₂ Al _2-z Si _z O _2-z N _2+z :Eu, where 0≤z≤0.1, and M2 includes one or more of (selected elements) from the group consisting of Sr and Ba. It is selected from the group consisting of

Thus, in a specific embodiment, the luminescent particles comprise a luminescent material selected from (above) SrLiAl ₃ N ₄ :Eu ²⁺ (class). The term “class” herein refers in particular to a group of materials having the same crystallographic structure(s). Additionally, the term “class” may also include partial substitutions of cations and/or anions. For example, in some of the above classes, Al-O may be partially replaced by Si-N (or vice versa). The class of SrLiAl ₃ N ₄ :Eu ²⁺ in particular can relate to a group of materials with the same crystallographic structure, in particular in which Sr has been partially replaced by divalent Eu, eg by 0.1% or 2%. there is. For example, Sr _0.995 LiAl ₃ N ₄ :Eu _0.005 and Sr _0.98 LiAl ₃ N ₄ :Eu _0.02 are elements in this class. Similarly SrLi ₂ Al _1.995 Si _0.005 O _1.995 N _2.005 :Eu ²⁺ classes (see also below) are for example Sr _0.999 Li ₂ Al _1.995 Si _0.005 O _1.995 N _2.005 :EU _0.001 and Sr _0.985 Li ₂ Al _1.995 Si _0.005 O _1.995 N _2.005 : EU _0.015 . Optionally also part of Sr can be replaced by another alkaline earth metal (group 2 elements of the periodic table). Examples of the SrLiAl ₃ N ₄ :Eu ²⁺ class are provided above. However, other light emitting materials may thus also be possible.

In further embodiments, the luminescent material (or phosphor) is (Sr,Ca)LiAl ₃ N ₄ :Eu, (Sr,Ca,Ba)Li _d Mg _a Al _b N ₄ :Eu (where 0≤a≤4 _{0≤b≤4 ; _ _ 2+z} : Eu (where 0≤z≤0.1).

Thus, the luminescent core may in particular comprise a phosphor. Furthermore, in particular the luminescent core comprises the luminescent material described herein, in particular in relation to the phosphor. Methods for providing luminescent particles with more than one, in particular multiple, hybrid coatings (and in particular more than one coating of luminescent cores) can be applied.

( above) SrLiAl ₃ N ₄ :Eu ²⁺ (class), and (ii) in particular the Eu doping concentration is in the range of 0.1-5%, in particular 0.1-2%, even more particularly 0.2-1.5% relative to Sr (above ) (phosphor) material selected from the group consisting of SrLi ₂ Al _1.995 Si _0.005 O _1.995 N _2.005 :Eu ²⁺ (class). Further, in particular, the third coating layer comprises SiO ₂ and at least one layer of the multilayer comprises at least one of Ta ₂ O ₅ , HfO ₂ , TiO ₂ and ZrO ₂ , wherein at least one (other) layer of the multilayer comprises The layers comprise Al ₂ O ₃ , in particular the layer here in contact with the main sol-gel coating layer consists of one or more metal oxides selected from the group HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ .

These luminescent particles may have a number average particle size in the range of 0.1-50 μm, such as in the range of 0.5-40 μm, such as in particular in the range of 0.5-20 μm. Thus, the light emitting core may have dimensions such as at most about 500 μm, such as at most about 100 μm, for example at most about 50 μm, and particularly with larger particle sizes, substantially only individual particles may be coated, such that on the order of 50 μm or less. Light emitting core dimensions are derived. Accordingly, the present invention relates to the coating of particles. The dimensions of the luminescent core can be substantially smaller when nanoparticles or quantum dots are used as the basis of the particulate luminescent material. In such case, the cores may be smaller or substantially smaller than about 1 μm (see also below for dimensions of QDs).

Alternatively or additionally, the luminescent particle(s), in particular the luminescent core(s), comprise luminescent quantum dots. The term “quantum dot” or “emissive quantum dot” may, in embodiments, refer to a combination of different types of quantum dots, ie, quantum dots with different spectral properties. QDs are also referred to herein as “wavelength converter nanoparticles” or “luminescent nanoparticles”. The term “quantum dots” refers in particular to quantum dots that emit light in one or more of UV, visible and IR (upon excitation with suitable radiation such as UV radiation). Quantum dots or luminescent nanoparticles, referred to herein as wavelength converter nanoparticles, for example CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe , HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, and II-VI compound semiconductor quantum dots selected from the group consisting of core-shell quantum dots having core-shell quantum dots). In another embodiment, the luminescent nanoparticles are, for example, GaN, GaP, GaAs, AlN, AlP, AlAs, InN, InP, InGaP, InAs, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs Group III-V compound semiconductor quantum dots selected from the group consisting of GaAlNPs, GaAlNAs, GaAlPAs, GaInNPs, GaInNAs, GaInPAs, InAlNPs, InAlNAs and InAlPAs (core-shell quantum dots having a core selected from the group consisting of) . In yet further embodiments, the luminescent nanoparticles are a core-shell quantum with a core selected, for example, from the group consisting of CuInS ₂ , CuInSe ₂ , CuGaS ₂ , CuGaSe ₂ , AgInS ₂ , AgInSe ₂ , AgGaS ₂ and AgGaSe ₂ ( dots) may be I-III-VI2 chalcopyrite-type semiconductor quantum dots selected from the group consisting of In yet a further embodiment, the luminescent nanoparticles are a IV-VI2 semiconductor quantum, for example selected from the group consisting of LiAsSe ₂ , NaAsSe ₂ and KAsSe ₂ (core-shell quantum dots with a core selected from the group consisting of). dots (core-shell quantum dots with a core selected from the group consisting of). In yet a further embodiment, the luminescent nanoparticles can be IV-VI compound semiconductor nanocrystals (core-shell quantum dots with a core selected from the group consisting of), for example SbTe. In a specific embodiment, the luminescent nanoparticles are selected from the group consisting of InP, CuInS ₂ , CuInSe ₂ , CdTe, CdSe, CdSeTe, AgInS ₂ and AgInSe ₂ (core-shell quantum dots with a core selected from the group consisting of) . In yet a further embodiment, the luminescent nanoparticles are selected from the above-described materials II-VI, III-V, I-III-V and IV- with inside dopants such as, for example, ZnSe:Mn, ZnS:Mn. may be one of a group of VI compound semiconductor nanocrystals (core-shell quantum dots with a core selected from the group consisting of). Dopant elements may be selected from Mn, Ag, Zn, Eu, S, P, Cu, Ce, Tb, Au, Pb, Tb, Sb, Sn and Ti. Herein, the luminescent material based on luminescent nanoparticles may also include different types of QDs, such as CdSe and ZnSe:Mn. The luminescent core may comprise one or more, in particular more (of the same or different) (types of) luminescent nanoparticles.

The use of II-VI quantum dots appears to be particularly advantageous. Thus, in embodiments semiconductor-based light emitting quantum dots are II-VI quantum dots, particularly CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSenST, core-shell quantum dots), and even more particularly those selected from the group consisting of CdS, CdSe, CdSe/CdS and CdSe/CdS/ZnS.

In embodiments, the wavelength converter nanoparticles have an average particle size in the range of about 1 to about 1000 nanometers (nm), preferably in the range of about 1 to about 100 nm. In embodiments, the nanoparticles have an average particle size ranging from about 1 to about 20 nm. In embodiments, the nanoparticles have an average particle size ranging from about 1 to about 10 nm. Luminescent nanoparticles (without coating) may have dimensions in the range of about 2-50 nm, such as 2-20 nm, particularly 2-10 nm, and even more particularly 2-5 nm; In particular at least 90% of the nanoparticles have dimensions in each indicated range (i.e. for example at least 90% of the nanoparticles have dimensions in the range of 2-50 nm, or in particular at least 90% of the nanoparticles have dimensions in the range of 2-50 nm) with dimensions in the range of -5 nm). The term “dimensions” relates to one or more of length, width, and diameter, particularly depending on the shape of the nanoparticles. Typical dots are made of binary alloys such as cadmium selenide, cadmium sulfide, indium arsenide and indium phosphide. However, dots can also be made from ternary alloys such as cadmium selenide sulfide. These quantum dots may contain as few as 100 to 100,000 atoms within a quantum dot volume with a diameter of 10 to 50 atoms. This corresponds to about 2 to 10 nanometers. For example, spherical particles such as CdSe, InP or CuInSe ₂ having a diameter of about 3 nm may be provided. Luminescent nanoparticles (without coating) can have the shape of spheres, cubes, rods, wires, disks, multi-pods, etc., with a dimension of less than 10 nm. For example, nanorods of CdSe with a length of 20 nm and a diameter of 4 nm may be provided. Thus, in embodiments semiconductor-based light emitting quantum dots include core-shell quantum dots. In still further embodiments, the semiconductor-based light emitting quantum dots include dots-in-rods nanoparticles. Combinations of different types of particles may also be applied. Here, the term "different types" may relate to different types of semiconductor light emitting materials as well as different geometries. Thus, combinations of two or more of quantum dots (as indicated above) or luminescent nanoparticles may also be applied.

In embodiments, the nanoparticles may comprise semiconductor nanocrystals comprising a core comprising a first semiconductor material and a shell comprising a second semiconductor material, wherein the shell is disposed over at least a portion of a surface of the core. Semiconductor nanocrystals comprising a core and a shell are also referred to as “core/shell” semiconductor nanocrystals. In particular any of the materials indicated above may be used as the core. Thus, the phrase “core-shell quantum dots having a core selected from the group consisting of” applies in some of the above lists of quantum dot materials. The term "core-shell" may refer to a gradient alloy shell, or a "core-shell-shell" including dot-in rods, and the like.

For example, a semiconductor nanocrystal can include a core having the formula MX, where M can be cadmium, zinc, magnesium, mercury, aluminum, gallium, indium, thallium, or mixtures thereof, and X is oxygen, sulfur , selenium, tellurium, nitrogen, phosphorus, arsenic, antimony, or mixtures thereof. Examples of materials suitable for use as semiconductor nanocrystal cores are ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, MgS, MgSe, GaAs, GaN, GaP, GaSe, GaSb, HgO, HgS, HgSe, HgTe , InAs, InN, InP, InGaP, InSb, AlAs, AlN, AlP, AlSb, TlN, TlP, TlAs, TlSb, PbO, PbS, PbSe, PbTe, Ge, Si, alloys comprising any of these, and/or or mixtures containing any of these (including ternary and quaternary mixtures or alloys).

The shell may be a semiconductor material having a composition that is the same as or different from that of the core. The shell comprises an overcoat of semiconductor material on the surface of the core, and the semiconductor nanocrystal comprises a group IV element, a group II-VI compound, a group II-V compound, a group III-VI compound, a group III-V compound, a group IV-VI. compounds, group I-III-VI compounds, group II-IV-VI compounds, group II-IV-V compounds, alloys comprising any of these, and/or mixtures comprising any of these (3 including circular and quaternary mixtures or alloys). Examples are ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, MgS, MgSe, GaAs, GaN, GaP, GaSe, GaSb, HgO, HgS, HgSe, HgTe, InAs, InN, InP, InGaP, InSb, AlAs, AlN, AlP, AlSb, TlN, TlP, TlAs, TlSb, PbO, PbS, PbSe, PbTe, Ge, Si, alloys comprising any of these, and/or mixtures comprising any of these However, it is not limited thereto. For example, ZnS, ZnSe or CdS overcoatings can be grown on CdSe or CdTe semiconductor nanocrystals. An overcoating process is described, for example, in US Pat. No. 6,322,901. By controlling the temperature of the reaction mixture during overcoating and monitoring the absorption spectrum of the core, overcoated materials with high emission quantum efficiencies and narrow size distributions can be obtained. An overcoating may include one or more layers. The overcoat includes at least one semiconductor material that is the same as or different from the composition of the core. Preferably, the overcoating has a thickness of about 1 to about 10 monolayers. The overcoating may also have a thickness greater than 10 monolayers. In embodiments, more than one overcoating may be included on the core.

In embodiments, the peripheral “shell” material may have a band gap greater than the band gap of the core material. In certain other embodiments, the peripheral shell material may have a band gap smaller than the band gap of the core material. In embodiments, the shell may be selected to have atomic spacing close to that of the “core” substrate. In certain other embodiments, the shell and core materials may have the same crystal structure.

Examples of semiconductor nanocrystal (core)shell materials may include, without limitation: red (eg, (CdSe)ZnS (core)shell), green (eg, (CdZnSe)CdZnS (core)shell, etc.) , and blue (eg (CdS)CdZnS (core)shell) (also see above for examples of specific wavelength converter nanoparticles based on additional semiconductors).

Thus, in embodiments the luminescent particle or luminescent core comprises a luminescent material selected from the group consisting of luminescent quantum dots comprising one or more core materials selected from the group consisting of CdS, CdSe, ZnS and ZnSe. Thus, in embodiments the luminescent particle or luminescent core may also be selected from a group of luminescent nanoparticles such as quantum dots or quantum rods of composition MX (M=Cd, Zn, X=Se, S). Such particles may have a number average particle size (ie, in particular length/width/height, diameter) in the range of 1-50 nm.

As discussed above, the luminescent particle includes a main ALD coating layer composed in particular of a primer layer. In embodiments, the luminescent particle may further comprise an additional ALD coating layer constructed on (on top of) the main sol-gel coating layers. The main ALD coating layer may be deposited by application of a main atomic layer deposition process ("main ALD process"). Additional ALD coating layers may be deposited by application of an additional atomic layer deposition process ("additional ALD process"). Both the main atomic layer deposition process and the (optional) additional atomic layer deposition process are atomic layer deposition processes (“ALD processes”). It will be appreciated that these processes may include the same ALD process. However, for example, the conditions of the main ALD process may differ from those of the additional ALD process. For example, the metal oxide precursor(s) used in the main ALD process may be different from the one(s) used in the additional ALD process. The deposition duration may be different, the temperature, etc. may be different. In particular, however, the metal oxide precursor(s) that can be applied in the further ALD process can be the metal oxide precursor(s) described in relation to the (main) ALD process (and vice versa).

Thus, the main ALD coating layer and optional additional ALD coating layers may be formed by an atomic layer deposition type process. In such a process, a polymeric network is formed by reaction of a metal oxide precursor with an oxygen source such as gaseous ozone and/or water. The ALD reaction is “divided” into (at least) two parts. In a first step, a metal (oxide) precursor is fed into an (ALD) reactor, where it adsorbs and/or reacts with reactive groups on particle surfaces, and purging the reactor removes substantially all unreacted or non-adsorbed material. Remove precursor molecules. In a second step, an oxygen source is fed into the reactor, which reacts with the metal source on the particle surfaces, followed by purging of the reactor to remove substantially all of the residual oxygen source molecules and hydrolysis products formed by the condensation reactions. Remove. Both steps lead to the formation of an atomic layer (or monolayer) due to the self-limiting nature of the surface reaction. These atomic layer reaction steps can be repeated multiple times to form the final ALD coating. The ALD process further enables the deposition of layers of different composition by continuously feeding different metal oxide precursors into the reactor to form multi-component layers or nanolaminates with tailored chemical, mechanical and optical properties (further see below).

The term “metal oxide precursor” refers in particular to a precursor of a metal oxide. The precursor itself may not be a metal oxide, but may include, for example, a metal organic molecule. Thus, metal (oxide) precursors, especially for ALD, may typically include metal halides, alkoxides, amides, and other metal (organic) compounds. The term metal oxide precursor may relate in particular to more than one different metal oxide precursor to more than one different metal oxides.

The step-by-step nature of the ALD process makes it possible to easily deposit defined layer thicknesses. The ALD process further enables the deposition of layers of different composition by continuously feeding different metal oxide precursors into the reactor to form multi-component layers or nanolaminates. Thus, in specific embodiments the main ALD coating layer (and/or additional ALD coating layers) comprises multiple layers (or nanolaminates) (see also below).

For the ALD process, among other things, a fluidized bed reactor can be applied.

Thus, in a specific embodiment the main ALD coating layer is provided by application of a (main) atomic layer deposition process. Additionally, in embodiments, an additional ALD coating layer is (also) provided by application of a (additional) ALD process. In embodiments, a static powder layer is used for the ALD coating of the primer layer and/or for the ALD coating of the main sol-gel coating. However, a fluid bed can also be applied (for one or more of the ALD processes). Other types of reactors may also be applied. As explained above, the primer layer may facilitate deposition of the main ALD coating layer, particularly by functioning as a nucleation layer or seed layer for the main ALD coating layer. In particular, reactive groups on the particle surface can be provided by the primer layer (and also by the main sol-gel coating layer).

For example, silanol groups on the surface of the sol-gel coating layer (assuming the primary and/or main silica sol-gel coating layer) act as reactive sites during ALD of the initial layers. In an embodiment, alumina is deposited by using Al(CH ₃ ) ₃ (TMA) as a metal oxide precursor and (subsequent exposure to water) water as an oxygen source. In the first reaction step, TMA is reacted with the surface silanol groups of the silica sol-gel coating layer according to:

The water then reacts with the metal oxide precursor in a second reaction step by hydrolysis followed by condensation reactions:

Additionally, particle aggregation can be substantially prevented by applying a primer sol-gel layer (and the main sol-gel coating layer), such as with a structured nano-porous surface of a silica sol-gel coating layer (see below).

The ALD process can be easily scaled up, and little powder or particle loss is observed during ALD coating. Commercially available ALD reactors for powder coating are sold, for example, by Picosun Oy with cartridge sample holders (POCA™). A system that can be used for the ALD process is described for example in WO 2013171360 A1, but other systems can also be applied.

Several suitable (non-limiting) materials for the ALD coating layer are listed in the table below:

Alternatively or additionally, niobium oxide (in particular Nb ₂ O ₅ ) or yttrium oxide (Y ₂ O ₃ ) may be applied. Its metal precursors are, for example, (tert-butylimido)-tris(diethylamino)-niobium, NbF ₅ or NbCl ₅ respectively, and tris(ethylcyclopentadienyl)yttrium. In further embodiments zinc oxide (ZnO) may be applied. Metal precursors thereof which can be applied, for example, are diethylzinc (DEZ), Zn(C ₂ H ₅ ) ₂ and dimethylzinc (DMZ) Zn(CH ₃ ) ₂ . However, other materials may also be applied. Thus, the metal oxide precursor in the atomic layer deposition process may be selected from the group of metal oxide precursors of metals including in particular Al, Zn, Hf, Ta, Zr, Ti and Sn (and optionally Si). Alternatively or additionally, metal precursors of one or more metals including Ga, Ge, V and Nb may be applied. Even more particularly, alternating layers of two or more of these precursors are applied, wherein at least one precursor is an Al metal oxide precursor and another precursor is a Hf metal oxide precursor, a Zn metal oxide precursor, a Ta metal oxide precursor. , selected from the group consisting of Zr metal oxide precursors, Ti metal oxide precursors and Sn metal oxide precursors, in particular as Hf metal oxide precursors, Ta metal oxide precursors, Ti metal oxide precursors and Zr metal oxide precursors selected from the group consisting of, for example, Hf metal oxide precursors, Ta metal oxide precursors and Zr metal oxide precursors, and even more particularly Ta metal oxide precursors. In particular Hf, Zr and Ta have been shown to provide relatively light transmissive layers, whereas Ti may, for example, provide relatively less light transmissive layers. Using TiCl ₄ as the metal oxide precursor (for the TiO ₂ layer) can provide a cost effective layer. Processing with Ta, Hf and Zr appears to be relatively easier than for example with Si. The terms “oxide precursor” or “metal oxide precursor” or “metal (oxide) precursor” may refer to a combination of two or more chemically different precursors. These precursors form oxides, especially upon reaction with an oxygen source (and are thus designated metal oxide precursors). The metal oxide precursors may be selected independently of one another for successive ALD cycles in embodiments. For example, in embodiments, a ZnO layer and an Al ₂ O ₃ layer are alternately deposited to obtain an AZO layer (Al ₂ O ₃ :ZnO, or “aluminum-doped zinc oxide layer”). The AZO layer can be a conductive layer and can be deposited using, for example, trimethylaluminum, diethylzinc, and water as an oxygen source. In further embodiments, (another) metal oxide is (also) deposited in multiple successive cycles (and optionally continuously further metal oxide is deposited optionally also in multiple successive cycles).

Further, the terms "metal oxide precursors of metals including Al, Zn, Hf, Ta, Zr, Ti and Sn", and "metal oxide precursors in an atomic layer deposition process include Al, Zn, Hf, Ta, Comparable terms in phrases such as "is selected from the group of metal oxide precursors of metals including Zr, Ti and Sn" are particularly suitable for given metals (in this context Al, Zn, Hf, Ta, Zr, Ti, Sn) refers to metal oxide precursors of metals selected from the group consisting of Additionally, in embodiments one or more metal oxides precursors are selected. For example, referring to the list given above, a metal oxide precursor "selected from the group of metal oxide precursors of metals comprising Al, Zn, Hf, Ta, Zr, Ti and Sn" is Al, Zn, Hf , any combination of metal oxide precursors of two or more metals selected from the group consisting of Ta, Zr, Ti and Sn. In embodiments, for example, the metal oxide precursor includes a combination of TaCl ₅ and HAl(CH ₃ ) ₂ . In further embodiments, the metal oxide precursor comprises only Al(CH ₃ ) ₃ .

Thus, in embodiments, the metal oxide precursor in the main atomic layer deposition process is a metal selected from the group consisting of Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V (and optionally Si) It is selected from the group of metal oxide precursors of In particular, in further embodiments, the metal oxide precursor in the main atomic layer deposition process is metal oxide precursors of metals including Al, Hf, Ta, Zr and Ti (particularly Al, Hf, Ta, Zr and Ti). metal oxide precursors of metals selected from the group consisting of). In further embodiments, Al(CH ₃ ) ₃ , HAl(CH ₃ ) ₂ , Hf(N(CH ₃ ) ₂ ) ₄ , Hf(N(CH ₂ CH ₃ ) ₂ ) ₄ in the main atomic layer deposition process. , Hf[N(CH ₃ )(CH ₂ CH ₃ )] ₄ , TaCl ₅ , Ta(N(CH ₃ ) ₂ ) ₅ , Ta{[N(CH ₃ )(CH ₂ CH ₃ )] ₃ N(C (CH ₃ ) ₃ )}, a metal oxide precursor selected from the group consisting of ZrCl ₄ , Zr(N(CH ₃ ) ₂ ) ₄ , TiCl ₄ , Ti(OCH ₃ ) ₄ and Ti(OCH ₂ CH ₃ ) ₄ , and an oxygen source selected from the group consisting of H ₂ O and O ₃ is applied. Additionally or alternatively, the metal oxide precursor in the (main) atomic layer deposition process is selected from the group consisting of Zn(C ₂ H ₅ ) ₂ and Zn(CH ₃ ) ₂ . In still further embodiments, additionally or alternatively, in the (main) atomic layer deposition process, the metal precursor is (tert-butylimido)-tris(diethylamino)-niobium, NbF ₅ , NbCl ₅ , and tris(ethylcyclopentadienyl)yttrium.

The metal oxide precursor(s) in the further atomic layer deposition process are in particular independently selected from the metal oxide precursor(s) in the main atomic layer deposition process, in particular (also) Al, Zn, Hf, Ta, Zr, Ti , Sn, Nb, Y, Ga and V (and optionally Si). In embodiments, (at least one of) the metal oxide precursor(s) in the additional atomic layer deposition process is a Si metal oxide precursor. In particular, in further embodiments, the metal oxide precursor in the further atomic layer deposition process is selected from the group of metal oxide precursors of metals selected from the group consisting of Al, Hf, Ta, Zr and Ti. In embodiments, the metal oxide precursor in the further atomic layer deposition process is Al(CH ₃ ) ₃ , HAl(CH ₃ ) ₂ , Hf(N(CH ₃ ) ₂ ) ₄ , Hf(N(CH ₂ CH ₃ ) ₂ ) ₄ , Hf[N(CH ₃ )(CH ₂ CH ₃ )] ₄ , TaCl ₅ , Ta(N(CH ₃ ) ₂ ) ₅ , Ta{[N(CH ₃ )(CH ₂ CH ₃ )] ₃ N(C(CH ₃ ) ₃ )}, ZrCl ₄ , Zr(N(CH ₃ ) ₂ ) ₄ , TiCl ₄ , Ti(OCH ₃ ) ₄ and Ti(OCH ₂ CH ₃ ) ₄ (also independently from the main ALD process) and an oxygen source selected from the group consisting of H ₂ O and O ₃ is applied. Additionally or alternatively, in the further atomic layer deposition process, the metal oxide precursor is selected from the group consisting of Zn(C ₂ H ₅ ) ₂ and Zn(CH ₃ ) ₂ . In still further embodiments, additionally or alternatively, the metal precursor in the additional atomic layer deposition process may be (tert-butylimido)-tris(diethylamino)-niobium, NbF ₅ , NbCl ₅ , and It is selected from the group consisting of tris(ethylcyclopentadienyl)yttrium.

In particular, in embodiments, in the main atomic layer deposition process and/or in the additional atomic layer deposition process, the metal oxide precursor is Al, Zn, Hf, Ta, Zr, Ti, Si, Sn, Nb, Y, Ga and V are selected from the group of metal oxide precursors of metals selected from the group consisting of.

A deposition temperature in the range of 200-350°C has been found to be most suitable for alumina ALD on the primer layer (and the main sol-gel coating layer), preferably the temperature is in the range of 250-300°C. Similar temperatures may apply for ALD of other metal oxide precursors for the ALD layer(s).

In specific embodiments, the main ALD coating layer comprises a multilayer with at least three layers having different chemical compositions, one or more of the layers comprising an oxide of Si (SiO ₂ ). In particular, such SiO ₂ layers are sandwiched between multiple other layers. Thus, in particular, the (ALD) layer (of the multilayer of the main ALD coating layer) in contact with the main sol-gel layer, and each (ALD) layer in contact with the primer layer are not composed of SiO ₂ . However, in embodiments the additional ALD coating layer in contact with the main sol-gel coating layer may include SiO ₂ . Thus, in embodiments, a metal oxide precursor of Si is selected in the (main and/or additional) atomic layer deposition process.

In particular, the main ALD alumina (or other metal oxide) layer has a thickness of 3-250 nm, in particular 5-250 nm, such as 5-100 nm, even more particularly 5-50 nm, such as 10-50 nm in particular. thickness, more particularly a thickness of 20-50 nm.

Adding the water gas permeation barrier properties of an alumina ALD layer by depositing at least one additional layer of a different oxide material such as ZrO ₂ , TiO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , HfO ₂ , Ta ₂ O ₅ can be improved by In particular, the thickness of the additional material layer is in the range of 1-40 nm, more preferably in the range of 1-10 nm. A nanolaminate stack of alternating layers of Al 2 O 3 _and a second oxide material more particularly from the group of ZrO ₂ , TiO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , HfO ₂ , SnO ₂ , Ta _{2 O 5} there are A suitable nanolaminate stack is, for example, 20×(1 nm Al ₂ O ₃ deposited at 250° C. to form a 40 nm thick nanolaminated second coating on the primer layer (and/or the main sol-gel coating layer). (10 ALD cycles)+1 nm ZrO ₂ (11 ALD cycles)).

The present invention provides, in particular embodiments, where the main ALD coating layer comprises a multi-layer comprising layers having different chemical compositions, and in an atomic layer deposition process the metal oxide precursor is - among other things - Al, Zn, Hf, Ta, Zr , Ti, Sn, Y, Ga, Ge, V and Nb (and optionally Si) selected from the group of metal oxide precursors of metals selected from the group consisting of Al, Hf, Ta, Zr and is selected from the group of metal oxide precursors of metals selected from the group consisting of Ti. Combinations of two or more of such precursors may also be used, for example a multilayer comprising alumina - mixed oxides of zirconium and hafnium - alumina, and the like. In specific embodiments, in the main atomic layer deposition process, the metal oxide precursors for two or more layers are selected from the group of metal oxide precursors of metals selected from the group consisting of Al, Hf, Ta, Zr and Ti.

Thus, in embodiments the main ALD coating layer may include a multilayer having (n) layers having different chemical compositions, where the multilayer is Al, Zn, Hf, Ta, Zr, Ti, Sn, Y, Ga , one or more layers comprising one or more oxides of Ge, V and Nb (and optionally Si), in particular the multilayer comprises one or more layers comprising one or more oxides of Al, Hf, Ta, Zr and Ti include One or more layers of such multilayers may also include mixed oxides as indicated above.

In further specific embodiments, the method of the present invention comprises successively providing n layers (onto the primer layer by application of a main atomic layer deposition process), in particular wherein each layer has a thickness of 1-50 nm , in particular having a layer coating layer thickness d21 in the range of 1-20 nm, for example 1-15 nm. The layer coating thickness may in embodiments be at least 2 nm, such as at least 5 nm, for example in the range of 5-40 nm, in particular 5-25 nm. The number of layers n is in particular at least 2, such as at least 3, or at least 4. In embodiments, n may be greater than 10. However, n is in particular less than or equal to 10, such as less than or equal to 5. In embodiments, 2≤n≤10, or particularly 2≤n≤5. It will be appreciated that an individual layer may be provided by one or more ALD cycles. Additionally, in particular adjacent (contact) layers contain different chemical compositions. In further embodiments, the one or more layers comprise one or more metal oxides selected from the group of HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ , in particular wherein the one or more (other) layers are Al ₂ O ₃ includes Additionally, it has been shown to be advantageous when the layer in contact with the main sol-gel coating layer consists of HfO ₂ and/or ZrO ₂ and/or TiO ₂ and/or Ta ₂ O ₅ . Thus, in further embodiments, the layer in contact with the main sol-gel coating layer consists of one or more metal oxides selected from the group HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ .

Thus, in specific embodiments, the method comprises successively providing n (ALD) layers onto the primer layer by application of a main atomic layer deposition process (to provide multiple layers), wherein each layer is having a layer coating layer thickness d21 in the range of 1-50 nm, in particular 1-20 nm, such as 1-15 nm, and 2<n≤50, in particular 2<n≤20, such as 2≤n≤10, in particular 2≤n≤5, one or more layers comprising one or more metal oxides selected from the group HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ , one or more layers comprising Al ₂ O ₃ , and wherein the layer in contact with the sol-gel coating layer is composed of one or more metal oxides selected from the group of HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ .

In particular, a (n ALD) multilayer coating comprising at least two (ALD) layers ("AB"), even more particularly at least three layers (eg "ABA"), and still more at least four layers (in particular main In the case of an ALD coating layer) is applied. Also more particularly applies a stack comprising at least two stacks of subsets of two (ALD) layers (“AB”), e.g. (AB) _n , where n is at least 2, e.g. 2-20, e.g. For is 2-10.

In particular, at least one of the multi-layered layers comprises an oxide of Al (optionally in combination with, for example, a further oxide of Si or another metal oxide as described herein), and at least one of the multi-layered layers comprises and one or more of the oxides of Hf, Zn, Ta, Zr, Ti, Y, Ga, Ge, V, Sn and Nb. Such layers may optionally also include Al, Zn, Hf, Ta, Zr, Ti, Sn, Si, Y, Ga, Ge, V and Nb, where Al is in the layer along with one or more of the other indicated elements. (when the different layer(s) of the multiple layers each contain an oxide of alumina). The term "ALD multilayer" or "multilayer" as indicated above refers in particular to layers having different chemical compositions. The phrase "layers with different chemical compositions" indicates that there are at least two layers with different chemical compositions, as in the case of "ABC" or in the case of (AB)n (n≥1).

Specific examples of (AB)n are wherein A is an oxide of Al and B is selected from one or more of oxides of Al, Zn, Hf, Ta, Zr, Ti, Sn, Y, Ga, Ge, V and Nb. and Al (and/or optionally Si) is in the layer together with one or more of the other indicated elements (when the other layer(s) of the multilayer each comprise an oxide of alumina), in particular when B is Hf, Zn, is selected from one or more of the oxides of Ta, Zr, Ti, Y, Ga, Ge, V and Nb, even more particularly B is selected from one or more of the oxides of Hf, Ta, Zr and Ti, more particularly B is selected from one or more of the oxides of Hf, Ta and Zr. In embodiments, B is further an oxide of Si (optionally in combination with one or more of the oxides of Al, Zn, Hf, Ta, Zr, Ti, Sn, Y, Ga, Ge, V and Nb) can include In particular, when (also) the SiO ₂ layer is deposited by ALD, the SiO ₂ (ALD) layer is deposited such that it is not in direct contact with the main sol-gel layer. For example, layer A (or layer B) of the multilayer may be a SiO ₂ layer, and layer B (or layer A) in contact with the main sol-gel layer may be an (ALD) layer having another chemical composition.

Thus, the main ALD multilayer is in particular provided on the primer layer. The main sol-gel layer is in particular provided on the main ALD multilayer. Additionally, as indicated above, optionally one or more further layers may be applied on top of the main sol-gel layer, in particular a further ALD layer may be provided on top of the main sol-gel layer. The additional ALD layer may include an ALD multilayer, eg, an ALD multilayer as described herein with respect to the main ALD multilayer.

In further specific embodiments, the method further comprises (iv) providing an additional ALD coating layer onto the light emitting core with the main sol-gel coating by application of an additional atomic layer deposition process. In particular, this provides further ALD coated luminescent particles. In the further atomic layer deposition process, the metal oxide precursors in particular include Al, Hf, Ta, including Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V (and optionally Si). It is selected from the group of metal oxide precursors including Zr, Ti. In embodiments, the additional ALD coating layer has a further ALD coating layer thickness (d4) in the range of 2-50 nm, in particular 10-50 nm, such as 10-20 nm. The additional ALD coating layer in particular has a chemical composition different from that of the main sol-gel coating layer.

In further embodiments, the additional ALD coating layer (optionally) comprises (provides including) an additional multi-layer having two or more (additional lower) layers having different chemical compositions, wherein one of the layers The above comprises metal oxides selected from the group of Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , ZnO and Ta ₂ O ₅ and at least two layers are chemical composition of the main sol-gel coating layer has a different chemical composition. In specific embodiments, in the further atomic layer deposition process, the metal oxide precursor for at least two (further lower) layers (of the further multilayer) is selected from the group consisting of Al, Hf, Ta, Zr and Ti It is selected from the group of metal oxide precursors of metals. The metal oxide precursor for the two or more (further lower) layers (of the further multilayer) is selected from the group of metal oxide precursors, in particular comprising Al, Hf, Ta, Zr, Ti.

Thus, in specific embodiments the main ALD coating layer comprises a multilayer with a stack of layers wherein adjacent layers have different chemical compositions. In particular, the multiple layers each independently have thicknesses in the range of 1-40 nm, in particular 1-10 nm. Further in particular, the multilayer comprises one or more alumina layers and one or more metal oxide layers, wherein the metal is selected from the group of Hf, Ta, Zr and Ti.

Thus, in specific embodiments, Al(CH ₃ ) ₃ , HAl(CH ₃ ) ₂ , Hf(N(CH ₃ ) ₂ ) ₄ , Hf(N(CH ₂ CH ₃ ) ₂ ) ₄ in an atomic layer deposition process, Hf[N(CH ₃ )(CH ₂ CH ₃ )] ₄ , TaCl ₅ , Ta(N(CH ₃ ) ₂ ) ₅ , Ta{[N(CH ₃ )(CH ₂ CH ₃ )] ₃ N(C( CH ₃ ) ₃ )}, a metal oxide precursor selected from the group consisting of ZrCl ₄ , Zr(N(CH ₃ ) ₂ ) ₄ , TiCl ₄ , Ti(OCH ₃ ) ₄ and Ti(OCH ₂ CH ₃ ) ₄ , and An oxygen source selected from the group consisting of H ₂ O and O ₃ is applied. As indicated above, also two or more different metal oxide precursors and/or two or more different oxygen sources may be applied.

Further, in embodiments of the method in the main atomic layer deposition process and/or in the additional atomic layer deposition process, in particular in the main atomic layer deposition process, multilayers with layers having different chemical compositions, wherein one or more of the layers are tantalum A multilayer comprising rum oxide (particularly Ta ₂ O ₅ ) is provided. Accordingly, the present invention also relates, in embodiments, to a luminescent material, wherein the main ALD coating layer comprises a multi-layer with layers having different chemical compositions, one or more of which may in particular comprise Ta ₂ O ₅ . A light emitting material is provided. Further, in the (main) atomic layer deposition process in embodiments of the method, as a multilayer with layers having different chemical compositions, wherein one or more of the layers are tantalum oxide (particularly Ta ₂ O ₅ ), hafnium oxide, A multilayer comprising at least one of titanium oxide and zirconium oxide is provided. Accordingly, the present invention is also in embodiments a luminescent material, in particular luminescent particles, wherein the main ALD coating layer comprises a multilayer with layers having different chemical compositions, one or more layers being in particular tantalum oxide, hafnium oxide , a luminescent material, particularly luminescent particles, which may include one or more of titanium oxide and zirconium oxide. For example, the multilayer stack may also contain alternating layers, for example in which alumina is alternating with one or more of tantalum oxide (particularly Ta ₂ O ₅ ), hafnium oxide, titanium oxide and zirconium oxide. stacks comprising, for example, alumina-tantalum oxide-alumina-hafnia-alumina-tantalum oxide, or alumina-titanium oxide-alumina, and the like.

Additionally, when the ALD coating was first applied on the core without a primer layer, the ALD layer was found to be less uniform than desired. In order to obtain a good ALD layer right on the core surface, the ALD layer thickness may have to be increased more than is in principle necessary in such embodiments, which may lead to (though in some cases small) an unnecessary decrease in transmittance. Additionally, after applying a primer layer to the core (even when not completely conformal), the ALD coating appeared to coat the core more easily.

As indicated above, a main sol-gel layer having an average thickness typically in the range of 50-700 nm, such as 50-600 nm, in particular 75-500 nm, such as in particular 100-500 nm, is formed by a sol-gel type process. is formed In such a process, an inorganic network is formed by subsequent hydrolysis to form a sol (colloidal suspension) from a homogeneous solution of precursors and then condensation to form a gel (crosslinked solid network) that is chemically bound to the powder surfaces. structure is formed. Preferably, the (main) sol-gel coating layer material is silica, and the sol-gel deposition method is described in Stoeber, W., A. Fink, et al., "Controlled growth of monodisperse silica spheres in the micron size range. ." It corresponds to the so-called Stoeber reaction as described in Journal of Colloid and Interface Science 26(1): 62-69. To this end, the luminescent particles (coated or uncoated) are dispersed in an alcohol such as methanol CH ₃ OH, ethanol C ₂ H ₅ OH or isopropanol C ₃ H ₇ OH, an aliphatic alcohol R—OH, followed by ammonia (NH in water). ₃ solution) and silicon alkoxide precursor. The silicon alkoxide precursor dissolves in the alcohol+ammonia mixture and begins to hydrolyze. by a seeding growth process consisting of reaction of the hydrolyzed but soluble sol species with reactive groups (eg amine or silanol groups) on the particle surfaces followed by steps of hydrolysis, nucleation and condensation reactions (coated or A conformal silica coating is formed on top of the uncoated) particle surfaces.

The term "particle surface (coated or uncoated)" in relation to a sol-gel coating process means, in particular, the surface of a particle (luminescent core) and/or the particle (luminescent core) in relation to a first sol-gel coating process. It may be related to the surface of the resulting layer (particularly the oxide-containing layer) of the phase. The term may further relate to the surface of the main ALD coating, especially in relation to the main sol-gel coating process.

에 의해 형성되는 화합물들의 군으로부터 선택되며, 여기서 a) R1, R2, R3은 가수분해성 알콕시 기들이고 R4는 C1-C6 선형 알킬 기들, 가수분해성 알콕시 기들 및 페닐 기의 군으로부터 선택되거나, 또는 b) R1, R2, R3은 -OCH₃ 및 -OC₂H₅로부터 개별적으로 선택되고 R4는 -CH₃, -C₂H₅, -OCH₃, -OC₂H₅ 및 페닐 기로부터 선택된다. 임의로, 규소 기반 중합체는Silicon alkoxide precursors are particularly

wherein a) R1, R2, R3 are hydrolysable alkoxy groups and R4 is selected from the group of C1-C6 linear alkyl groups, hydrolysable alkoxy groups and phenyl groups, or b) R1, R2, R3 are individually selected from -OCH ₃ and -OC ₂ H ₅ and R4 is selected from -CH ₃ , -C ₂ H ₅ , -OCH ₃ , -OC ₂ H ₅ and a phenyl group. Optionally, the silicon-based polymer

It is obtained from materials from the group of

로 이루어진 화합물들의 군으로부터 선택되고, 여기서 a) R1, R2, R3은 가수분해성 알콕시 기들이고 R4는 C1-C6 선형 알킬 기들, 가수분해성 알콕시 기들 및 페닐 기의 군으로부터 선택되거나, 또는 b) R1, R2, R3은 -OCH₃ 및 -OC₂H₅로부터 개별적으로 선택되고 R4는 -CH₃, -C₂H₅, -OCH₃, -OC₂H₅ 및 페닐 기로부터 선택된다.Thus, in embodiments of the method, in the main sol-gel coating process, a silicon alkoxide precursor is used, wherein the silicon alkoxide precursor is in particular

wherein a) R1, R2, R3 are hydrolysable alkoxy groups and R4 is selected from the group of C1-C6 linear alkyl groups, hydrolysable alkoxy groups and phenyl groups, or b) R1, R2, R3 are individually selected from -OCH ₃ and -OC ₂ H ₅ and R4 is selected from -CH ₃ , -C ₂ H ₅ , -OCH ₃ , -OC ₂ H ₅ and a phenyl group.

In further embodiments of the method, in the main sol-gel coating process, a silicon alkoxide precursor is used and the silicon alkoxide precursor is

is selected from the group consisting of

In further embodiments of the method, in the first sol-gel coating process, silicon alkoxide precursors are used, in particular the silicon alkoxide precursors are silicon alkoxides as described herein in connection with the main sol-gel coating process. may be a precursor. The silicon alkoxide precursor in the primary sol-gel coating process can be independently selected from the silicon alkoxide precursor in the main sol-gel coating process.

In particular, the silicon alkoxide precursor (in the main and/or primary sol-gel coating process) is selected from the group of Si(OCH ₃ ) ₄ or Si(OC ₂ H ₅ ) ₄ , more particularly Si(OC ₂ H ₅ ) ₄ is used as a silicon alkoxide precursor. Similar precursors but based on another metal, for example Al, may also be used.

A typical sol-gel coating process may include the following stages: (a) while stirring or sonicating the particles or powder, in particular the luminescent cores (optionally with an oxide-containing layer and/or a main ALD coating layer) Suspension in an alcohol-aqueous ammonia solution mixture. To improve particle dispersion, the particles (cores/powder) can also first be mixed with an alcohol and a small amount of silicon (or other metal) alkoxide before adding the ammonia solution. (b) adding a silicon (or other metal) alkoxide precursor under agitation to the suspension. Typical concentrations of silicon (or other metal) alkoxide, ammonia and water in alcohol solvent are 0.02-0.7, 0.3-1.5 and 1-16 mole/l respectively. (c) Stir or sonicate the suspension until a coating forms. (d) The coated powder is washed with alcohol, dried and then calcined at 200-300°C in air or vacuum.

Thus, in embodiments the main sol-gel coating process comprises (iiia) providing a mixture of alcohol, ammonia, water, a light emitting core(s) with (a primer layer and) a main ALD coating layer, and a metal alkoxide precursor; , forming a main sol-gel coating layer on the main ALD coating layer while stirring the mixture, wherein the metal alkoxide precursor is in particular a titanium alkoxide, a silicon alkoxide or an aluminum alkoxide; and (iiib) recovering from the mixture (a primer layer) a light emitting core(s) having a main ALD coating layer and a main sol-gel coating layer, optionally comprising a primer layer, a main ALD coating layer and a main sol-gel coating layer. and performing a heat treatment on the recovered luminescent core(s) to provide luminescent particle(s) with a hybrid coating.

Thus, in further embodiments, the first sol-gel coating process comprises (ib1) the luminescent core(s) optionally equipped with alcohol, ammonia, water, the wash result layer, in particular the luminescent core(s) and the wash result layer ( or providing a mixture of the light emitting core(s) comprising the washed result layer and the metal alkoxide precursor and stirring the mixture while applying the first sol-gel coating layer onto the washed result layer and/or the light emitting core without the washed result layer ( s) on, in particular on the washing result layer, wherein the metal alkoxide precursor is in particular selected from titanium alkoxides, silicon alkoxides or aluminum alkoxides; and (ib2) recovering the luminescent core(s) with (the washing result layer and) the first sol-gel coating layer from the mixture, optionally, the recovered luminescence having the (wash result layer and) the first sol-gel coating layer. and performing a heat treatment on the core(s) to provide a light-emitting core(s) comprising (equipped with) a primer layer on the light-emitting core.

로 이루어진 화합물들의 군으로부터 선택되어 사용될 수 있으며, 여기서 R1, R2, R3은 가수분해성 알콕시 모이어티들로 이루어진 군으로부터 선택되고, R4는 C1-C6 선형 알킬 모이어티들, 가수분해성 알콕시 모이어티들, 및 페닐 모이어티로 이루어진 군으로부터 선택된다. 임의로 알콕시드들 이외의 다른 리간드들이 졸-겔 공정을 위한 전구체에서 적용될 수 있다.The process of recovering the core(s) (with the respective (coating) layers) from the mixture may include, for example, one or more of filtration, centrifugation, decanting (liquid over sediment), and the like. The thermal treatment may include at least one of drying and calcination, in particular both, ie a drying stage at a temperature in the range of eg 70-130° C. followed by a calcination stage (in air; or in a vacuum or (other) inert atmosphere). can Thus, during a portion of the thermal treatment time, the (coated) luminescent material may be in an inert environment such as vacuum, or one or more of N ₂ and noble gases, or the like. Heat treatment appears to improve the stability of the luminescent material. Additionally, as indicated above, in the (main and/or primary) sol-gel coating process, silicon (or other metals; although the formula below refers to Si) alkoxides and especially precursors

Wherein R1, R2, R3 are selected from the group consisting of hydrolysable alkoxy moieties, R4 is C1-C6 linear alkyl moieties, hydrolysable alkoxy moieties, and a phenyl moiety. Optionally other ligands than alkoxides may be applied in the precursor for the sol-gel process.

Particles obtained with the sol-gel coating process may optionally contain more than one nucleus. In the case of quantum dots, for example, agglomerates with a (primary and/or main) sol-gel coating can be obtained. Thus, a silica precursor (or other metal oxide precursor) can also coat multiple QDs with thin single shells (particularly including the main ALD coating layer) to form a coated agglomerate. This may depend, among other things, on the concentration of quantum dots and the like.

In the foregoing, precursors for sol-gel coating are described in particular with reference to silicon alkoxide precursors. However, aluminum (or another metal) alkoxide precursor(s) may also be applied. Additionally, also combinations of two or more chemically different precursors may be applied to provide the sol-gel coating layer or the first coating layer.

The term “sol-gel coating process” can also relate to a plurality of sol-gel coating processes. A plurality of sol-gel coating processes, in particular a plurality of main sol-gel coating processes, may provide (multiple) layers comprising substantially the same composition over the entire layer thickness (e.g., the (main) sol - when each coating stage or step in a gel coating process involves depositing substantially the same material), or having different compositions, such as a stack of two or more (sol-gel) layers each having two or more different compositions. Multilayers with two or more layers may be provided. An example may be a SiO ₂ -Al ₂ O ₃ (sol-gel) multilayer, such as a stack of eg three or more (sol-gel) layers in which SiO ₂ and Al ₂ O ₃ are present alternately. (See also above).

To facilitate deposition of the main ALD coating layer, the luminescent core may include a primer layer. In embodiments, the primer layer comprises a first sol-gel coating layer (optionally including multiple layers), particularly that provided by a (first) sol-gel coating process. The first sol-gel coating layer can facilitate deposition of the (thin) conformal main ALD coating layer. To further assist in the deposition of the main ALD coating layer, the surface of the core is provided with a first sol-gel layer and/or a main ALD coating layer after cleaning in embodiments.

In order to facilitate the main ALD deposition process, in particular to enable the deposition of a single ALD layer or multiple layers with as few defects as possible, any material that may be present in the powder (raw product, in particular one comprising a plurality of light emitting cores) Chemically reactive contamination (also known as "second phases") can be removed. Preferably, small particles, typically those having sub-micrometer dimensions and capable of adhering to the surface of the phosphor particles (luminescent core) are also removed prior to deposition of the main ALD coating process. Cleaning of the surface of the core may in particular include a (chemical) cleaning process. In embodiments, the core may be cleaned by applying an aqueous liquid, by applying a cleaning process. Such aqueous liquids may contain acids or bases or may consist of, for example, water (having a neutral pH). Water may be applied, for example, to remove unwanted small particles and some of the second phases. However, for the purpose of removing additional impurities, the pH of the aqueous liquid may be altered, for example to pH values of at least 8, in particular at least 9, or to pH values of less than 6, in particular less than 5. In this way, for example, impurities can be dissolved. In further embodiments, a non-aqueous solvent may be applied, especially for particles (cores) that may be water sensitive. Thus, in particular, aqueous liquids containing additives (eg for changing the pH), non-aqueous solvents, or combinations of these liquids/solvents may be applied. Thus, a cleaning/cleaning process may be referred to as a "chemical cleaning process", in particular by applying a cleaning solvent (including an aqueous liquid).

If the chemical stability of the phosphor (luminescent core) in water, bases and/or acids is limited, washing procedures with very mild conditions may be applied to remove the second phases without dissolving (part of) the phosphor particles. can This can be achieved by choosing weak acids instead of strong acids with pKa values that can be selected according to the stability of the phosphor and impurity phases (see below). Additionally or alternatively, a non-aqueous solvent is first applied to the luminescent core(s) (phosphors) to give a suspension (of luminescent particles/cores) and successively the total amount of water and acid concentration is dissolved only in the impurity phase. Degradation of the phosphor in the washing process can be avoided by adding a weak acid (or weak base) sufficient to dissolve it.

Wash solvents with a pH of less than 7 are useful for hydrolysis sensitive phosphors because they react as a base in an aqueous medium. The acidity of such wash solvents may be low. Specifically, organic acids such as acetic acids diluted in a polar solvent having a low proton concentration such as aliphatic alcohols (eg ethanol or isopropanol) as described above may be used as the washing solvent. The more sensitive the phosphor is, the more dilute the wash solvent must be (i.e., the lower the proton concentration), since the goal of the cleaning process is to remove basic impurity phases and to aid in the adhesion of subsequent primer layers without degrading the phosphor. This is because it creates a surface in Thus, in general, the washing solvent is selected by reducing the acid concentration, replacing the solvent with another solvent having a lower dielectric constant, when a person skilled in the art observes that too much of the luminescent particle material is degraded or dissolved in the washing process. Furnace replacement and/or cooling of the wash suspension may reduce the amount of degradation.

After washing, the number of fine particles in the phosphor powder can be further reduced by settling in non-reactive liquids (typically polar organic solvents, such as absolute ethanol, or other alcohols). In embodiments, ultrasound is applied to the suspension prior to settling to better desorb and disperse the fine particles from the larger phosphor grains.

As a result of the chemical cleaning process, a thin layer with a different composition compared to the nominal composition of the luminescent particle (luminescent core) can be formed on the surface of the particle (core). That is, the surface composition of the microparticle luminescent particles may be slightly different from the overall composition of the microparticle luminescent material. In particular, the thin layer (ie surface) may include a higher oxygen concentration (content) than (the nominal composition of) the luminescent core. Applying a chemical wash may in embodiments provide a layer resulting from the wash onto the luminescent core. The cleaning process can provide a surface that aids in the adhesion of a subsequent primer layer (a layer resulting from washing). The thin layer/surface may contain, for example, alkaline earth elements (e.g., strontium), aluminum, and oxide (e.g., coating alkaline earth aluminate type hydrolysis sensitive luminescent materials such as those disclosed herein). when you want). The surface layer may contain elements such as lithium, silicon, europium, carbon and/or hydrogen depending on the light emitting material. The layer resulting from washing in particular comprises an oxide-containing layer. The layer resulting from washing does not necessarily conformally and/or entirely cover the surface of the luminescent core (see also above regarding the primer layer). The layer resulting from washing may not be a continuous layer, and may include, for example, a plurality of layer portions each covering only a portion of the surface of the light emitting core. The resulting layer of washing may be evenly distributed over (the surface of) the light emitting core in embodiments. The resulting wash layer may in embodiments cover the core on at least 30% of the surface of the core, such as at least 50%, particularly at least 75%, such as at least 90%, or particularly at least 95% or even more particularly at least 99%. there is.

Experimentally, it was found that even with the application of a mild wash solvent, the layer as a result of the wash was observable. In particular, in the case of nitride or oxonitride compounds, a higher O:N ratio may be present in the washed resulting layer. The luminescent core especially comprises nitride or oxonitride compounds. In embodiments, the luminescent material, particularly of the luminescent core, comprises a nitride luminescent material (core). In further embodiments, the luminescent material in particular of the luminescent core (also) comprises an oxonitride luminescent material (core).

Thus, in further embodiments, the method further comprises (ia) providing a washed result layer onto the light emitting core by application of a chemical cleaning process, in particular wherein the washed result layer comprises an oxide-containing layer It includes the step of doing. In further embodiments, application of the chemical cleaning process includes drying the luminescent core(s) after removal of the cleaning solvent. The washing result layer may be provided during washing of the luminescent core with a washing solvent and/or during drying of the luminescent core. In further embodiments, a first sol-gel coating is provided after application of a chemical cleaning process (optionally including drying of the luminescent core). Application of a chemical cleaning process may provide washed luminescent particles comprising a layer resulting from washing onto the luminescent core.

Thus, in further embodiments, the method further comprises a first sol onto the luminescent core and the washed result layer (or onto the luminescent core comprising the washed result layer) by application of a first sol-gel coating process. - providing a gel coating layer to provide a primer layer comprising a wash result layer and a first sol-gel layer, in particular wherein the primer layer has a primer layer thickness (d1) in the range of 0.1-5 nm. Include steps.

The wash solvent may include an aqueous solvent in embodiments. Herein, this (cleaning with solvents including aqueous solvents) can also be denoted as "wet chemical cleaning process". In embodiments, for example, the wash solvent includes a strong acid or strong base. These terms are known in the art. Examples of strong acids are HCl, HBr, HClO ₄ , HI, HNO ₃ . Examples of strong bases are eg NaOH, KOH, CaOH. However, in further embodiments, the wash solvent comprises a weak acid or weak base. Examples of weak acids that can be used are, for example, acetic acid, formic acid, hydrofluoric acid, trichloroacetic acid, citric acid, oxalic acid and the like. Examples of weak bases are, for example, ammonia, sodium bicarbonate, alanine, and methylamine.

In particular, weak acids or weak bases (in water at room temperature) having a pK _a value or a pK _b value of greater than 3, in particular greater than 4, respectively may be selected. In embodiments, the wash solvent comprises one or more weak acids selected from the group of acetic acid, formic acid, hydrofluoric acid, trichloroacetic acid, citric acid, oxalic acid. The washing solvent may in particular include formic acid or acetic acid. In further embodiments, the wash solvent comprises one or more of weakly basic ammonia, sodium bicarbonate, alanine and methylamine. Wash solvents may include in particular a combination of a non-aqueous fluid with a weak acid or weak base. For example, the wash solvent may in embodiments be an alcohol (eg, propanol, isopropyl alcohol, ethanol, (cyclo)hexanol, or any other alcohol having one or more hydroxy groups) and a weak acid, such as formic acid. and/or acetic acid. Alternatively, the wash solvent may include mixtures of alcohols and polyols in embodiments. In embodiments, for example, the wash solvent includes traces as a mixture of ethanol and triethylene glycol, and in particular water, which acts as a dissolution catalyst. Such a combination can advantageously be applied for cleaning of luminescent particles (cores) that can easily deteriorate under the influence of water. The wash solvent may in embodiments include less than 50 wt % water (by weight of the wash solvent). The wash solvent may include, for example, 40 wt % or less water, such as 35 wt % or less water. In embodiments, the wash solvent may include 25 wt % or less water. In particular, the wash solvent (comprising a (weak) base or (weak) acid) comprises at least 5 wt % water, such as at least 10 wt % water. In embodiments, however, the wash solvent is a non-aqueous wash solvent. Additionally, the application of weak acids (and weak bases) may have an additional benefit in that they may provide a pH buffering function. As such, if an extra amount of weak acid (or weak base) is added to the wash solvent (eg, even if not all impurities have yet been removed by the wash solvent), the pH of the wash solvent may not change substantially. The use of weak acids or bases can increase the robustness of the wet cleaning process.

Thus, in further embodiments, the chemical cleaning process comprises, inter alia, (i) washing the luminescent core by applying a washing solvent (process), wherein the washing solvent is a (weak) acid or (weak) base, in particular ( weak) an acid, and the wash solvent comprises no more than 50% wt/wt water, especially water in the range of 10-35% wt/wt, and optionally. (ii) continuously performing a drying treatment on the light emitting core to provide a light emitting core including a layer as a result of washing on (and onto) the light emitting core.

An oxygen-containing layer may be provided on the luminescent particles, in particular based on a washing process (optionally including a drying treatment).

The different (coating) layers (primary layer, main ALD-layer, main sol-gel coating layer and further ALD coating layer) which can be constituted in the light emitting core are in particular light transmissive. This means that at least part of the light impinging on each layer is transmitted through each layer. Thus, the different (coating) layers may be fully or partially transparent or translucent. In an embodiment, more than 90% of the (visible light) light impinging on the (coating) layers is transmitted through the (coating) layers. The (coating) layers may be light transmissive due to the characteristics of the materials that make up the coating layers. For example, the coating layer may be made from a material that is transparent even if the layer is relatively thick. In another embodiment, one or more of the (coating) layers are thin enough such that each layer is light transmissive, while the material of the layer being made is not transparent or translucent when made in relatively thick layers. The materials described herein may all be transmissive to (visible light) light or made of suitable layer thicknesses that are transmissive to (visible light) light.

In a further aspect, the invention also relates to a lighting device comprising a light source configured to generate light source radiation, in particular at least one of blue and UV, and a wavelength converter comprising a luminescent material as described herein, wherein the wavelength converter provides a lighting device configured to convert at least a portion of the light source radiation into wavelength converter light (eg, one or more of green, yellow, orange and red light). The wavelength converter is in particular radiatively coupled to the light source. The term "radiation coupled" means in particular that the light source and the light emitting material are associated with each other such that at least a portion of the radiation emitted by the light source is received by the light emitting material (and at least partially converted into light emission). Thus, the luminescent cores of the particles can be excited by the source radiation providing luminescence of the luminescent material within the core. In embodiments, the wavelength converter comprises a matrix (material) comprising a luminescent material (particles). For example, the matrix (material) is PE (polyethylene), PP (polypropylene), PEN (polyethylene naphthalate), PC (polycarbonate), polymethylacrylate (PMA), polymethylmethacrylate ( PMMA) (Plexiglas or Perspex), cellulose acetate butyrate (CAB), silicone, polyvinylchloride (PVC), polyethylene terephthalate (PET), (PETG) (glycol modified polyethylene terephthalate) , PDMS (polydimethylsiloxane), and a permeable organic material support, such as selected from the group consisting of COC (cyclo olefin copolymer). Alternatively or additionally, the matrix (material) may include an epoxy resin.

In forming such a lighting device, the use of the coatings disclosed herein makes it possible to use hydrolysis sensitive phosphors as the light emitting material in the wavelength converter. In particular, a luminescent material that is likely to deteriorate under conditions used to form a matrix in which luminescent particles are embedded to form a wavelength converter can be used in lighting devices (shown in Fig. 3 below). For example, alkaline earth aluminate luminescent materials, or luminescent materials having alkaline earth aluminate type surface layers after the cleaning process disclosed herein. Such hydrolysis-sensitive luminescent materials are (above) SrLiAl ₃ N ₄ :Eu ²⁺ (class) wherein optionally also part of Sr can be replaced by another alkaline earth metal (group 2 elements of the periodic table), for example. ). And also, for example, (Sr,Ca)LiAl ₃ N ₄ :Eu, (Sr,Ca,Ba)Li _d Mg _a Al _b N ₄ :Eu (where 0≤a≤4; 0≤b≤ _{4 ; _ _ _} (Where 0≤z≤0.1) a light emitting material (or phosphor) selected from the group consisting of. And also, for example, the above-described SrLi ₂ Al _2-x SiO _2-x N _2+x :Eu or (Sr,Ca)SiAlN ₃ :Eu. Using the coating disclosed herein, such hydrolysis-sensitive light emitting materials can be used in processes for forming wavelength converters in a matrix, such as silicone resins, which may otherwise degrade uncoated light emitting materials. It is possible to use in processes for forming wavelength converters in which luminescent particles are embedded.

The lighting device may be for example office lighting systems, home application systems, store lighting systems, residential lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fibre-optic application systems, projection systems, self-illuminating display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive It may be part of or be applied in applications, greenhouse lighting systems, horticultural lighting, or LCD backlighting.

As indicated above, the lighting unit can be used as a backlighting unit in an LCD display device. Accordingly, the present invention also provides an LCD display device comprising a lighting unit as defined herein, configured as a backlighting unit. The invention also provides, in a further aspect, a liquid crystal display device comprising a backlighting unit, wherein the backlighting unit comprises one or more lighting devices as defined herein.

In particular, the light source is a light source that emits light (light source radiation) of a wavelength in the range of at least 200-490 nm during operation, in particular a light source which emits light of a wavelength in the range of at least 400-490 nm, even more particularly in the range of 440-490 nm during operation. It is a light source. Such light may be used in part by wavelength converter nanoparticles (see also further below). Thus, in a specific embodiment, the light source is configured to generate blue light. In a specific embodiment, the light source comprises a solid state LED light source (eg LED or laser diode). The term “light source” may also relate to a plurality of light sources, such as 2-20 (solid state) LED light sources. Accordingly, the term LED may refer to a plurality of LEDs. The term white light herein is known to a person skilled in the art. It is in particular between about 2000 and 20000 K, especially 2700-20000 K, especially in the range of about 2700 K and 6500 K for general lighting, and especially in the range of about 7000 K and 20000 K for backlighting purposes, and in particular BBL (black body locus). ), specifically within about 10 SDCM from BBL, and even more particularly within about 5 SDCM from BBL. In an embodiment, the light source may also include light source radiation having a correlated color temperature (CCT) between about 5000 and 20000 K, for example direct phosphor conversion LEDs (e.g. blue with a thin layer of phosphor to obtain 10000 K light emitting diode). Thus, in a specific embodiment the light source is configured to provide light source radiation with a correlated color temperature in the range of 5000-20000 K, even more particularly in the range of 6000-20000 K, such as in the range of 8000-20000 K. An advantage of a relatively high color temperature may be that there may be a relatively high blue component in the source radiation.

The term “controlling” and similar terms refers in particular to at least determining the behavior or supervising the operation of an element. Thus, "controlling" and similar terms herein refer to imposing a behavior on an element (determining a behavior or activating an element), e.g., measuring, displaying, actuating, opening, moving, changing a temperature, etc. supervision), etc. Additionally, the term “controlling” and similar terms may additionally include monitoring. Thus, the term “controlling” and similar terms can include imposing a behavior on an element, and also imposing a behavior on an element and monitoring the element. Control of the elements may be performed with a control system, which may also be referred to as a “controller”. Thus, the control system and elements can be functionally coupled, at least temporarily, or permanently. An element may include a control system. In embodiments, control systems and components may not be physically coupled. Control may be performed via wired and/or wireless control. The term “control system” may refer to a plurality of different control systems, which are in particular functionally coupled, of which for example one control system may be a master control system and one or more others may be slave control systems. can The control system may include a user interface or may be functionally coupled thereto.

The control system may also be configured to receive and execute instructions from the remote control. In embodiments, the control system may be controlled via an app on a device such as a smartphone or portable device such as an iPhone, tablet, or the like. Thus, the device is not necessarily coupled to the lighting system, but can be (temporarily) functionally coupled to the lighting system.

Thus, in embodiments the control system may (also) be configured to be controlled by an app on a remote device. In such embodiments the control system of the lighting system may be a slave control system, or control in slave mode. For example, a lighting system may be identifiable by a code, particularly a unique code for each lighting system. The control system of the lighting system may be configured to be controlled by an external control system that accesses the lighting system based on its knowledge (entered by its user interface) using an optical sensor (eg QR code reader) of the (proprietary) code. . The lighting system may also include means for communicating with other systems or devices, such as based on Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

A system or apparatus or device may execute an action in a “mode” or “mode of operation” or “mode of operation”. Similarly, an action or stage or step in a method may be executed in a “mode” or “mode of operation” or “mode of operation” or “operational mode”. The term "mode" can also be denoted as "control mode". This does not exclude that the system or apparatus or device may also be adapted to provide another control mode or a plurality of other control modes. Likewise, this may not exclude that one or more other modes may be executed before execution of the mode and/or after execution of the mode.

However, in embodiments, a control system adapted to provide at least a control mode may be available. If other modes are available, the selection of those modes can in particular be effected via the user interface, but other options such as executing a mode according to a sensor signal or (time) scheme may also be possible. A mode of operation may, in embodiments, refer to a system or apparatus or device capable of operating in only a single mode of operation (ie, “on”, without further tunability).

Thus, in embodiments, the control system can control in accordance with one or more of an input signal from a user interface, a sensor signal (of a sensor), and a timer. The term "timer" can refer to a clock and/or a predetermined time scheme.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying schematic drawings in which corresponding reference numerals indicate corresponding parts, wherein:
1 schematically shows the sides of a luminescent particle;
2a-2b schematically depict some additional aspects of a luminescent particle;
3 schematically shows a lighting device;
4a-4b show SEM and TEM images of luminescent particles;
5A-5B show some experimental results comparing embodiments of the present invention to prior art phosphors.
6A-6B show schematic cross-sectional and plan views of an array of pcLEDs, respectively.
Figure 7a shows a schematic plan view of an electronics board on which an array of pcLEDs can be mounted, and Figure 7b similarly shows an array of pcLEDs mounted on the electronics board of Figure 7a.
8A shows a schematic cross-sectional view of an array of pcLEDs disposed with respect to waveguides and a projection lens. Figure 8b shows an arrangement similar to that of Figure 8a, without the waveguides.
9 schematically illustrates an example camera flash system that includes an adaptive lighting system.
10 schematically illustrates an example display (eg, AR/VR/MR) system that includes an adaptive lighting system.
Schematics are not necessarily to scale.

1 schematically illustrates an embodiment of luminescent particles 100 . The luminescent particle 100 includes a luminescent core 102 that includes a primer layer 105 on the luminescent core 102 . A luminescent core 102 with a primer layer 105 is herein also referred to as a primer layer 105 comprising luminescent particles 100 . The primer layer 105 has a chemical composition different from that of the core 102 . The luminescent core 102 may include, for example, micrometer dimension particles of a luminescent nitride or sulfide phosphor, but may also include other (smaller) materials such as luminescent nanoparticles (further FIG. 2B ). reference).

The luminescent particle 100 further includes a main ALD coating layer 120 . In the illustrated embodiment the main ALD coating layer 120 comprises a multilayer 1120 having three layers 1121, a layer 1121a, a layer 1121b and a layer 1121c. The three layers 1121a, 1121b, 1121c in particular have (at least two) different chemical compositions. In particular, adjacent (and contacting) disposed layers 1121 have different compositions. Additionally, one or more of the layers 1121 of the multilayer 1120 may have chemical compositions different from (also) the chemical composition of the primer layer 105 . Layers 1121 may include different oxides of Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V, for example, in embodiments. Additionally or alternatively, layers 1121 may include Si and/or Ge. In particular one of the layers 1121 may be an alumina layer.

The luminescent particle 100 further comprises a main sol-gel coating layer 130 having a different chemical composition than, in particular, one or more of the layers 1121 of the multilayer 1120 . The figure further shows that the main ALD coating layer 120 is disposed between the primer layer 105 and the main sol-gel layer 130 . In particular, adjacently disposed/contacting coating layers may have different compositions. In the figure shown, the layer 1121a has a different composition than that of the main sol-gel layer 130 in particular. The layer 1121c has a different composition than that of the primer layer 105 in particular. Thus, the hybrid coating of the embodiment in FIG. 1 includes a primer layer ( 105 ), a main ALD layer ( 120 ) and a main sol-gel coating layer ( 130 ). In further embodiments, see for example FIG. 2A , the hybrid coating further includes an additional ALD coating layer 140 .

The embodiment of FIG. 2A also includes an additional ALD coating layer 140 disposed on the main sol-gel coating layer 130 . In the illustrated embodiment, the additional ALD coating layer 140 (also) comprises two (further lower) layers 1141, 1141a, 1141b (of the further multilayer 1140). An additional multi-layer 1140 is included. However, in other embodiments the additional ALD coating layer 140 is (deposited as) a single layer. 2a also indicates the thicknesses of the layers. Note that thicknesses are not to scale and are shown only to illustrate the meaning of terms and to indicate location. The primer layer thickness is indicated by reference symbol d1. The primer layer thickness d1 may be in the range of 0.1-5 nm. The ALD coating layer thickness is indicated by reference symbol d2. The ALD coating layer thickness d2 may in particular range from 5-250 nm. The thickness of the main sol-gel coating 130 is indicated by reference symbol d3. The main sol-gel coating layer thickness (d3) is generally greater than the ALD coating layer thickness (d2). The main sol-gel coating layer thickness d3 is in particular in the range of 50-700 nm. The illustrated embodiment comprises a multilayer 1120 with three layers 1121, each layer 1121 having a layer coating layer thickness d21 in the range of 1-20 nm. In the illustrated embodiment, the layer coating thickness d21 of the three layers 1121 is approximately equal. The layer coating thickness d21 may vary between the different layers 1121, but see FIG. 4B for example. The three layers 1121a, 1121b and 1121c may show alternating Al ₂ O ₃ layers (eg 1121b) and Ta ₂ O ₅ layers (eg 1121a, 1121c) that are present alternately, for example. . The (further lower) layer coating layer thickness of the (further lower) layers 1141 of the further multi-layer 1140 (not denoted by reference numeral) is in particular the layer coating layer thickness of the layers 1121 of the multi-layer 1120 within the ranges as described with respect to (d21).

2A further schematically shows that the primer layer 105 comprises an oxide containing layer 101 and a first sol-gel layer 110 . Oxide-containing layer 101 is disposed on surface 67 of core 102 . In an embodiment, the oxide-containing layer 101 and the first sol-gel layer 110 are continuous and conformal. However, in additional embodiments this may not be the case, for example the main ALD coating layer 120 may contact the oxide-containing layer 101 at some locations, and even the core of the core at some additional locations. surface 67 (while contacting primary sol-gel layer 110 at different locations).

FIG. 2A further denotes the surfaces of the respective layers at 17 , 27 , 37 , 47 , 57 and the surface of core 102 at 67 . As indicated above, the layer thicknesses described herein are in particular average layer thicknesses. In particular at least 50%, even more particularly at least 80% of the area of each layer has such an indicated layer thickness. Thus, referring to the surface 47 and the thickness d2 between the surface 37, a layer thickness can be found at least 50% below the surface 37, for example in the range of 5-250 nm, and the surface area On average, (d2) of the main ALD coating (multi-)layer 120 is in the indicated range of 5-250 nm, although at least less than 50% of the remainder of (37) can be found in smaller or larger thicknesses, for example. is within Likewise, this may apply to other thicknesses indicated herein. For example, referring to the thickness d3 between surface 37 and surface 27, the thickness may be in the range of 50-700 nm over at least 50% of the area of surface 27, and the surface area 27 ), on average the first layer (d1) of the main sol-gel layer 130 has a thickness of 50-700 nm, such as in particular 100- It is within the indicated range of 500 nm.

2B schematically depicts an embodiment in which the luminescent core 102 comprises luminescent nanoparticles (quantum dots 160 here as an example). A quantum dot in this example includes a quantum rod with a (semiconductor) core material 161 such as ZnSe, and a shell 162 such as ZnS. Of course, other luminescent nanoparticles may also be used. Such light-emitting quantum dots 160 may also be provided with a hybrid coating.

1-2 schematically depict luminescent particles 100 having single nuclei. Optionally, however, agglomerates encapsulated with the hybrid coating may also be formed. This is particularly applicable to quantum dots as luminescent particles defining the luminescent core 102 .

The figures show, in particular, embodiments of the coating architecture on phosphor particles or luminescent cores 102 (after application of the respective (ALD and sol-gel) coating processes). The phosphor particles 102 may be covered by an oxide layer 101 formed by a washing and baking process. The primary sol-gel coating 110 includes, in embodiments, silicon oxide (SiO ₂ ) provided by a (primary) sol-gel coating process. The first SiO ₂ layer 110 acts as a nucleation or seed layer for the main ALD coating layer 120 , in particular provided by the main atomic layer deposition process. Thus, the first sol-gel coating layer 110 (as well as the first layer 105) need not form a conformal or fully closed coating around each core 102. The primary sol-gel coating layer 110 , for example the primary SiO ₂ layer 110 , can also be considered as a surface treatment to provide OH-groups on the phosphor particles 102 . Such OH-groups can assist ALD precursors to bind onto the surface and consequently initiate film growth.

The main ALD coating layer 120 includes, in particular, a multi-layer 1120, also referred to as a “nanolaminate” 1120 of (sub-)layers 1121 of metal oxides. The nanolaminate 1120 can form an extremely dense, virtually pinhole-free conformal coating on phosphor particles that is nearly impermeable to gases such as water vapor and oxygen. The nanolaminate protective layer 1120 is, in embodiments, 20-50 nm composed of more than two sublayers of Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , ZnO or Ta ₂ O ₅ . It may have a thickness (d2) of Each layer 1121 may have a thickness d21 ranging from 1 nm to 15 nm. The outer layer 1121, i.e., the layer in contact with the main sol gel coating layer 130 (1121a in FIGS. 1 and 2A) may, in embodiments, be exposed to water or other solvents such as cyclohexanone. It is a chemically stable layer such as HfO ₂ , ZrO ₂ or Ta ₂ O ₅ that does not corrode when exposed to heat.

The main sol-gel coating layer 130 may also include silicon oxide (SiO ₂ ) provided by a (main) sol-gel coating process, similar to the first sol-gel coating layer 110 . The main sol-gel coating 130 may, in particular, function as a mechanical protection to prevent damage to the underlying barrier coating 120. In the LED manufacturing process, phosphor particles go through various process steps such as mixing, sieving, pressing and molding. These process steps can induce mechanical stress in the coating. As a result, the coating may be damaged. The main sol-gel coating layer 130 provides high robustness for post-processing and fabrication steps. High reliability in the embodiments can be ensured by applying the main main sol-gel coating layer 130 on the luminescent particles 100 .

In embodiments of the invention, an additional ALD coating layer 140 is added to the layer architecture, as shown in FIG. 2A. An additional ALD coating layer 140 in an embodiment includes a nanolaminate 1140. Layer 140 or multilayer 1140 may include metal oxides such as Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , ZnO or Ta ₂ O ₅ . The total thickness d4 of layer 140 is in particular in the range of 10-50 nm. The additional ALD coating layer 140 may further stabilize the overall coating structure by filling the pores and pinholes in the main sol-gel coating layer 130 . In addition, the additional ALD coating layer 140 may suppress surface reactivity of the main sol-gel layer 130 . The surface reactivity can be beneficial in maintaining the rheology or other properties of certain silicone phosphor slurries in embodiments of LED manufacturing processes.

3 shows a light source 10 configured to generate light source radiation 11, in particular at least one of blue and UV, as well as a luminescent material 1 having particles 100 as defined herein. A lighting device 20 comprising a wavelength converter 30 is schematically shown. Wavelength converter 30 may include, for example, a matrix, such as a silicone or organic polymer matrix as described above, in which coated particles 100 are embedded. The wavelength converter 30 is configured to convert (wavelength) at least a portion of the light source radiation 11 into wavelength converter light 31 . Optionally also the light source radiation 11 can pass (unconverted) through the wavelength converter 30 . Wavelength converter light 31 includes at least emission from the coated particles 100 described herein. However, wavelength converter 30 may optionally also include one or more other luminescent materials. The wavelength converter 30, or more particularly the light emitting material 1, may be disposed at a non-zero distance d30, for example at a distance of 0.1-100 mm. Optionally, however, the distance d30 can be zero (eg, when the light emitting material is embedded in a dome on the LED die). Distance d30 is the shortest distance between a light emitting surface of light source 10, such as an LED die, and wavelength converter 30, more particularly light emitting material 1.

Light source 10 may be an LED, such that lighting device 20 is a phosphor-converter LED (“pcLED”). For example, light source 10 may be a III-nitride LED that emits ultraviolet, blue, green or red light. LEDs formed from any other suitable material system and emitting light of any other suitable wavelength may also be used. Other suitable material systems may include, for example, III-phosphide materials, III-arsenide materials, and II-VI materials.

4A shows a SEM image of a light emitting material 1 including partially coated light emitting particles 100 . In Fig. 4b, a TEM image of a coated luminescent particle 100 is given, which includes two Al ₂ O ₃ layers 1121 b and two Ta ₂ O ₅ layers 1121 a and a (SiO ₂ ) main sol-gel coating. A core (102) having an oxide-containing layer (101), a primary (SiO ₂ ) sol-gel coating layer (110), and a main ALD coating layer (120), comprising a multilayer (1120) of (130). clearly indicate.

5A-5B show some experimental results. In the figures, coated luminescent particles 100 of the present invention (here comprising SrLiAl ₃ N ₄ :Eu) are compared to corresponding prior art luminescent particles. Prior art luminescent particles also include an ALD coating layer and a sol-gel coating layer. However, the sol-gel coating layer is composed directly on the surface of the light emitting core 102, and the ALD coating layer is composed on the sol-gel coating.

In Fig. 5a, the (normalized) light output over time (Y-axis), in particular the times (X-axis) of each light-emitting particle in silicon is given. During the experiment, the particles were maintained at 130° C. and 100% relative humidity. Circular markers indicate the luminescent particles 100 of the present invention; Square markers indicate prior art luminescent particles.

In Fig. 5b, the probability of failure of white LEDs with each light emitting particle is given after maintaining each LED at 85 DEG C and 85% relative humidity for more than 500 hours. square markers indicate the luminescent particles 100 of the present invention; Circular markers indicate prior art luminescent particles. Note that probabilities are given as percentages on a logarithmic scale on the Y-axis. The color point shift in Δu'v' (sometimes denoted "(du'v')" or "duv") is given on the X-axis. The luminescent particles 100 (including LEDs) of the present invention obviously have a smaller color shift (Δu'v' is (u', v') the Euclidean value between a pair of chromaticity coordinates in the CIE 1976 color space. calculated as distance).

Accordingly, the present invention relates to methods of improving the barrier properties of phosphor particle coatings. The present invention is generally applicable to a variety of phosphor particles, but in particular to nitride based narrowband red-emitting phosphors such as nitride aluminates or oxo nitride aluminates due to their high sensitivity to moisture. Suitable.

6A-6B show cross-sectional and top views, respectively, of an array 600 of pcLEDs 610, which pcLEDs 610 may be structured as a lighting device 20 as shown in FIG. 3, which is a substrate and a wavelength converter 30 comprising coated luminescent particles 100 as defined herein contained within phosphor pixels 606 with a semiconductor diode 612 disposed on 602 . Such an array may include any suitable number of pcLEDs arranged in any suitable manner. Although in the illustrated example the array is shown monolithically formed on a shared substrate, the array of pcLEDs may alternatively be formed from separate individual pcLEDs. Substrate 602 may optionally include CMOS circuitry for driving LEDs, and may be formed from any suitable materials.

6A-6B show a 3x3 array of 9 pcLEDs, but such arrays may include tens, hundreds or thousands of LEDs, for example. Individual LEDs (pixels) may have widths (eg, side lengths) in the plane of the array, for example, 1 millimeter (mm) or less, 500 micrometers or less, 100 micrometers or less, or 50 micrometers or less. can The LEDs in such an array are interconnected by streets or lanes having a width in the plane of the array of, for example, several hundred micrometers, less than 100 micrometers, less than 50 micrometers, less than 10 micrometers, or less than 5 micrometers. can be separated Although the illustrated examples show rectangular pixels arranged in a symmetric matrix, the pixels and array may have any suitable shape or arrangement.

LEDs whose in-plane dimensions (eg, side lengths) of the array are less than or equal to about 50 micrometers are typically referred to as microLEDs, and an array of such microLEDs may be referred to as a microLED array.

An array of LEDs, or portions of such an array, is such that individual LED pixels are electrically isolated from each other by trenches and/or insulating material, but with the electrically isolated segments physically connected to each other by portions of a semiconductor structure. It can be formed as a segmented monolithic structure that is maintained.

Individual LEDs in an LED array may be individually addressable, addressable as part of a group or subset of pixels in the array, or may not be addressable. Thus, light emitting pixel arrays are useful in any application that requires or benefits from fine-grained intensity, spatial and temporal control of light distribution. These applications may include, but are not limited to, precise special patterning of the emitted light from pixel blocks or individual pixels. Depending on the application, the emitted light may be spectrally distinct, adapt over time, and/or react environmentally. Such light emitting pixel arrays can provide a pre-programmed light distribution of various intensities, spatial or temporal patterns. The emitted light may be based at least in part on received sensor data and may be used for optical wireless communications. Associated electronics and optics can be differentiated at the pixel, pixel block, or device level.

As shown in FIGS. 7A-7B , the pcLED array 600 can be mounted on an electronics board 700 that includes a power and control module 702 , a sensor module 704 , and an LED attachment area 706 . there is. The power and control module 702 receives power and control signals from external sources and signals from the sensor module 704 based on which power and control module 702 controls the operation of the LEDs. can do. Sensor module 704 may receive signals from any suitable sensors, such as temperature or light sensors. Alternatively, pcLED array 600 may be mounted on a separate board (not shown) from the power and control module and sensor module.

The individual pcLEDs may optionally be disposed in combination with or including a lens or other optical element disposed on or adjacent to the phosphor layer. Such an optical element not shown in the figures may be referred to as a “primary optical element”. 8A-8B, pcLED array 600 (e.g., mounted on electronics board 700) may include waveguides, lenses, or both for use in the intended application. It may be arranged in combination with other secondary optical elements. In FIG. 8A , light emitted by pcLEDs 610 is collected by waveguides 802 and guided to a projection lens 804 . Projection lens 804 may be, for example, a Fresnel lens. This arrangement may be suitable for use in automotive headlights, for example. In FIG. 8B , light emitted by pcLEDs 610 is directly collected by projection lens 804 without the use of intervening waveguides. This arrangement can be particularly suitable when the pcLEDs can be spaced close enough to each other, and can also be used in automotive headlights as well as camera flash applications. A microLED display application may use optical arrangements similar to those shown in FIGS. 8A-8B, for example. In general, any suitable arrangement of optical elements can be used in combination with the LED arrays described herein, depending on the desired application.

An array of independently operable LEDs may be used in combination with a lens, lens system, or other optical system (eg, as described above) to provide lighting that is adaptable for a particular purpose. For example, in operation, such an adaptive lighting system can provide lighting that varies by color and/or intensity across an illuminated scene or object and/or is aimed in a desired direction. The controller may be configured to receive data indicative of positions and color characteristics of objects or people in the scene and, based on that information, control the LEDs in the LED array to provide lighting tailored to the scene. Such data may be provided by, for example, an image sensor, or optical (eg laser scanning) or non-optical (eg millimeter radar) sensors. Such adaptive lighting is becoming increasingly important for automotive, mobile device camera, VR and AR applications.

9 schematically illustrates an example camera flash system 900 that includes an LED array and lens system 902, which may be similar or identical to the systems described above. The flash system 900 also includes an LED driver 906 controlled by a controller 904, such as a microprocessor. Controller 904 may also be coupled to camera 907 and sensors 908 and may operate according to instructions and profiles stored in memory 910 . Camera 907 and adaptive lighting system 902 can be controlled by controller 904 to match their field of view.

Sensors 908 may include, for example, position sensors (eg, gyroscopes and/or accelerometers) and/or other sensors that may be used to determine the position, velocity, and orientation of system 900. there is. Signals from the sensors 908 are fed to the controller 904 for the appropriate course of action of the controller 904 (e.g., which LEDs are currently illuminating the target and which LEDs are illuminating the target after a predetermined amount of time). can be used to decide what to do).

In operation, the illumination from some or all pixels of the LED array at 902 may be regulated—disabled, operated at full intensity, or operated at medium intensity. Beam focusing or steering of the light emitted by the LED array in 902 is performed on one or more subsets of pixels to enable dynamic adjustment of the beam shape without moving optics or changing the focus of lenses within the lighting device. It can be done electronically by activating them.

10 is an exemplary display (eg, AR/VR/MR) system including an adaptive light emitting array 1010, a display 1020, a light emitting array controller 1030, a sensor system 1040, and a system controller 1050. (1000) is schematically illustrated. Control inputs are provided to sensor system 1040 while power and user data inputs are provided to system controller 1050. In some embodiments, modules included within system 1000 may be compactly arranged in a unitary structure, or one or more elements may be separately mounted and connected via wireless or wired communication. For example, the light emitting array 1010, display 1020 and sensor system 1040 can be mounted on a headset or glasses, and the light emitting controller and/or system controller 1050 can be mounted separately.

Light emitting array 1010, as described above, may include one or more adaptive light emitting arrays that may be used to project light into graphic or object patterns that may support AR/VR/MR systems, for example. can In some embodiments, arrays of microLEDs may be used.

System 1000 may include, for example, a wide range of optics on adaptive light emitting array 1010 and/or display 1020 to couple light emitted by adaptive light emitting array 1010 to display 1020. device can be introduced.

Sensor system 1040 may include, for example, cameras to monitor the environment, external sensors such as depth sensors or voice sensors, and accelerometers or 2 or 3 axis gyro to monitor AR/VR/MR headset position. It may include internal sensors such as scopes. Other sensors may include, but are not limited to, air pressure, stress sensors, temperature sensors, or any other suitable sensors needed for local or remote environmental monitoring. In some embodiments, control input can include sensed touches or taps, gesture input, or control based on headset or display position.

In response to data from sensor system 1040 , system controller 1050 may send images or instructions to light emitting array controller 1030 . Changes or transformations to images or instructions may also be made by user data input, or automated data input, as needed. User data input may include, but is not limited to, spoken commands, haptic feedback, eye or pupil positioning, or provided by an attached keyboard, mouse, or game controller.

In an embodiment, the present invention provides a process for wet chemical cleaning (including drying) of a powdered phosphor (luminescent core(s)) to form an oxide outer particle layer. A further primary (SiO ₂ ) sol-gel layer can be deposited by a (first) sol-gel process to provide a primary sol-gel layer with a thickness in the range of 0.5-5 nm. Next, the multilayer is subjected to ALD to obtain a total ALD coating layer thickness (d2) of 20-50 nm in embodiments and a (sub)layer thickness (d21) of the layers (1121) of the multilayer (1120) in the range of 1-20 nm. can be calmed down by Multilayer 1120 is composed of two or more metal oxides, particularly Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , ZnO, Ta ₂ O ₅ . Next, a third layer, in particular a main sol-gel coating layer 130 of eg SiO ₂ , can be deposited by a (main) sol-gel process to a thickness in the range of 100-500 nm. In still further embodiments, the fourth layer 140 can be deposited by an additional ALD process. The additional ALD coating layer 140 may have a total thickness (d4) of 5-50 nm in embodiments, and in particular may comprise multiple layers with sublayer thicknesses in the range of 1-20 nm. The multilayer is in embodiments composed of one or more metal oxides such as Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , ZnO, Ta ₂ O ₅ .

Experiment

The effectiveness of the novel coating architecture of the present invention was tested by forming luminescent particles with a hybrid coating as disclosed herein:

Polyol washing process:

A 10.3 g sample of raw phosphor powder of the composition Sr _0.995 Li ₂ Al _1.995 Si _0.005 O _1.995 N _2.005 :Eu _0.005 was mixed with 30.0 g ethanol and 30.0 g triethylene glycol in an ultrasonic bath to form a suspension exhibiting a total water content in the range of 0.05-0.1%. After mixing, it was treated for 16 hr at 80° C. in a closed pressure vessel. After cooling to room temperature, the phosphor powder was washed with ethanol and dried at 100° C. under ambient atmosphere.

Mixed solvent acetic acid washing process:

200-250 g of SrLiAl ₃ N ₄ :Eu _0.007 were stirred in 837 g of isopropanol. 560 g of 18.5 wt% acetic acid was added slowly under stirring. The suspension was further stirred until a total time of 40 min (including acid addition) had elapsed. After 30 min sedimentation, the supernatant was mostly removed by decanting, then filtered, and rinsed with an acetic acid/isopropanol mixture and isopropanol. Finally, the washed phosphors were dried in vacuo at 50° C. overnight.

Thin amorphous silica layer (<5 nm)

In this experiment, a first sol-gel coating layer was provided. 200 g of phosphor powder (typically after washing) was stirred in 960 g of ethanol. To this suspension was added 3.5 g of tetraethyl orthosilicate and stirred for 10 min under sonication. 90 g of 25 wt% aqueous ammonia solution were added and stirring under sonication was continued for a further 20 min. Fine particles, including nano-sized silica particles formed as by-products, were removed by 3-fold sedimentation in ethanol, and decantation. The coated powder was dried overnight in vacuum at 50 °C. After dry-sieving (mesh size 100 μm), the coating was cured by heating the powder to 300° C. for 10 hr under vacuum.

ALD nanolaminate (~25 nm)

Next, a main ALD coating layer comprising an ALD nanolaminate was applied on a primer layer comprising phosphor particles (comprising SrLiAl ₃ N ₄ :Eu) in a picosoon owai ALD R200 reactor. The precursor materials are trimethylaluminum and H ₂ O to form an Al ₂ O ₃ film, and (tert-butylimido)tris(ethylmethylamino) tantalum (V) and H ₂ to form a Ta ₂ O ₅ film. It was O. The deposition temperature was set at 250°C. The nitrogen gas purge time between precursor pulses was 60 seconds. The nanolaminate consists of 2xAl ₂ O ₃ /Ta ₂ O ₅ sublayers with a total thickness of approximately 25 nm.

Thick amorphous silica layer (~170 nm)

In this experiment, the main sol-gel coating layer was provided on the luminescent particles. 85 g of powder (typically after ALD coating) was stirred in 672 g of ethanol for 15 min under sonication. To this suspension 1) 116 g of 25 wt % aqueous ammonia solution was added rapidly (<30 s) and 2) a solution of 68 g of tetraethyl orthosilicate in 408 g of ethanol was added dropwise (˜45 min). After the addition of the alkoxide precursor was complete, the suspension was stirred for another 30 min without sonication.

Fine particles, including sub-micrometer-sized silica particles formed as by-products, were removed by 3-fold sedimentation in ethanol, and decantation. The coated powder was dried overnight in vacuum at 50 °C. After dry-sieving (mesh size 63 μm), the coating was cured by heating the powder to 300° C. for 10 hr under vacuum.

An SEM image of some of the particles is given in Figure 4a. A TEM image of the particles is given in Figure 4b.

comparison test

Stress testing was performed on the prepared particles in silicon and compared to control particles (ie, particles comprising a prior art coating architecture). In prior art coating architectures, the luminescent particles are first coated with a relatively thick sol-gel coating and subsequently with a thin ALD coating. In the stress test, the light output was measured over time while the particles were maintained at a temperature of 130° C. and 100% relative humidity.

The prepared particles were further applied in a white LED and stressed for over 500 hours at 85° C. and 85% relative humidity. The failure probability of white LEDs with luminescent particles according to the present invention was compared to the failure probability of white LEDs with prior art coating architecture subjected to the same stress test (control LED).

The results are shown in FIGS. 5A-5B showing a significantly improved reduction in light output (i.e., less than 5% compared to greater than 50% reduction for control particles) after 60 hours of stress testing. Also, the color shift (Δu'v') is substantially minimized compared to the control LED.

The term “plurality” refers to two or more.

The terms "substantially" or "essentially" and similar terms herein will be understood by those skilled in the art. The terms "substantially" or "essentially" may also include embodiments such as "entirely", "completely", "all", and the like. Thus, in embodiments adjectives may also be substantially or essentially removed. Where applicable, the term "substantially" or the term "essentially" may also relate to 90% or more, including 100%, such as 95% or more, particularly 99% or more, even more particularly 99.5% or more. .

The term “comprises” also includes embodiments in which the term “comprises” means “consisting of”.

The term “and/or” relates specifically to one or more of the items mentioned before and after “and/or”. For example, the phrase "item 1 and/or item 2" and similar phrases may relate to one or more of items 1 and 2. The term “comprising” can refer to “consisting of” in an embodiment, but can also refer to “containing at least the defined species and optionally one or more other species” in another embodiment.

In addition, the terms first, second, third, etc. in the description and claims are used to distinguish between similar elements, and are not necessarily used to describe sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein may operate in sequences other than those described or exemplified herein.

Devices, apparatus or systems may be described herein for operation among other things. As will be apparent to those skilled in the art, the present invention is not limited to methods of operation, or devices, apparatus or systems in operation.

It should be noted that the foregoing embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Use of the verb "to include" and its related forms does not exclude the presence of elements or steps other than those stated in a claim. Throughout the description and claims, unless the context clearly requires otherwise, the words "comprises", "comprising", etc. are to be interpreted in an inclusive sense as opposed to an exclusive or inclusive sense (i.e., "including but not limited thereto"). in the sense of "but not limited to").

An article preceding an element does not exclude the presence of a plurality of such elements.

The invention may be practiced by means of hardware comprising several distinct elements and by means of a suitably programmed computer. In a device claim or apparatus claim or system claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The present invention also provides a control system capable of controlling a device, apparatus or system or carrying out a method or process described herein. Still further, the invention also provides a computer program product that, when run on a computer functionally coupled to or configured by a device, apparatus or system, controls one or more controllable elements of such device, apparatus or system. .

The invention further applies to a device, apparatus or system comprising one or more of the characterizing features described in the description and/or shown in the accompanying drawings. The invention further relates to a method or process comprising one or more of the characterizing features set forth in the description and/or shown in the accompanying drawings.

The various aspects discussed in this patent can be combined to provide additional advantages. Additionally, one skilled in the art will understand that the embodiments may be combined, and also that more than two embodiments may be combined. In addition, some of the features may form the basis for one or more divisional applications.

Claims (37)

As a method for providing luminescent particles with a hybrid coating,
(i) providing a particulate luminescent material having a surface;
(ii) forming a primer layer directly on at least a portion of the surface;
(iii) depositing a first ALD layer by performing a first atomic layer deposition process on the particulate light emitting material having a primer layer, the first atomic layer deposition process comprising Al, Zn, Hf, Ta, Zr, Ti, using a metal oxide first precursor selected from the group of metal oxides including Sn, Nb, Y, Ga and V;
(iv) performing a second atomic layer deposition process to deposit a second ALD layer onto the first ALD layer, the second atomic layer deposition process comprising Al, Zn, Hf, Ta, Zr, Ti, Sn, using a metal oxide second precursor different from the first precursor and selected from the group of metal oxides comprising Nb, Y, Ga and V; and
(iv) performing a main sol-gel coating process to form a main sol-gel coating layer directly onto the second ALD layer, wherein the main sol-gel coating layer has a chemical composition different from the first ALD layer and the second ALD layer. having a composition
How to include. The method of claim 1, wherein forming the primer layer directly on at least a part of the surface of the particulate light emitting material comprises performing a primer sol-gel coating process using a metal alkoxide precursor on the particulate light emitting material. how it would be. The method of claim 2, wherein the primer sol-gel coating process,
suspending the particulate luminescent material in an alcohol-aqueous ammonia solution mixture;
adding a metal alkoxide precursor to the mixture;
stirring the mixture containing the metal alkoxide until a primer layer is formed;
washing the particulate luminescent material having the primer layer with alcohol; and
Drying the particulate light emitting material having a primer layer
A method comprising 3. The method of claim 2, wherein the metal alkoxide precursor is a silicon alkoxide. The method of claim 1 , further comprising the step of washing the particulate luminescent material in a wash solvent prior to forming the primer layer, wherein the wash solvent has a pH < 7. 6. The method of claim 5, wherein the wash solvent comprises an organic acid. 6. The method of claim 5, wherein the wash solvent comprises an aliphatic alcohol. 6. The method of claim 5, wherein the washing solvent comprises a weak acid and less than 50% wt/wt water, and washing the particulate light emitting material comprises:
continuously performing a drying treatment on the particulate light emitting material;
How to further include. The method of claim 1 , wherein the primer layer has a primer layer thickness in the range of 0.1-5 nm, and wherein the primer layer comprises a first sol-gel layer provided by application of a first sol-gel coating process. According to claim 1,
(i) the primer layer has a primer layer thickness (d1) in the range of 0.1-5 nm;
(ii) the first ALD layer and the second ALD layer form a main ALD coating layer, the main ALD coating layer having a main ALD coating layer thickness (d2) in the range of 5-250 nm;
(iii) the main sol-gel coating layer has a main sol-gel coating layer thickness (d3) in the range of 50-700 nm.
method. The method of claim 1 wherein the metal oxide first precursor is Al and the metal oxide second precursor is selected from metal oxides including Al, Hf, Ta, Zr and Ti. The method of claim 1, wherein the main sol-gel coating process,
Main sol-gel directly onto the second ALD layer by providing a mixture of alcohol, ammonia, water, a primer layer and a particulate light emitting material having a first ALD layer and a second ALD layer, and a metal alkoxide precursor and stirring the mixture. forming a coating layer, wherein the metal alkoxide precursor is titanium alkoxide, silicon alkoxide, and or aluminum alkoxide; and
A particulate luminescent material having a primer layer, a first ALD layer and a second ALD layer, and a main sol-gel coating layer is recovered from the mixture, and the primer layer, the first ALD layer and the second ALD layer, and the main sol-gel coating layer are formed. performing a heat treatment on the recovered particulate luminescent material having
A method comprising The method of claim 1, wherein in the main sol-gel coating process, a silicon alkoxide precursor is used, and the silicon alkoxide precursor is

It is selected from the group consisting of, and in the first and second atomic layer deposition processes, Al(CH ₃ ) ₃ , HAl(CH ₃ ) ₂ , Hf(N(CH ₃ ) ₂ ) ₄ , Hf(N(CH ₂ CH ₃ ) ₂ ) ₄ , Hf[N(CH ₃ )(CH ₂ CH ₃ )] ₄ , TaCl ₅ , Ta(N(CH ₃ ) ₂ ) ₅ , Ta{[N(CH ₃ )(CH ₂ CH ₃ ) ] ₃ N(C(CH ₃ ) ₃ )}, ZrCl ₄ , Zr(N(CH ₃ ) ₂ ) ₄ , TiCl ₄ , Ti(OCH ₃ ) ₄ , Ti(OCH ₂ CH ₃ ) ₄ selected from the group consisting of A metal oxide first precursor and a metal oxide second precursor, and an oxygen source selected from the group consisting of H ₂ O and O ₃ are applied. According to claim 1,
providing n additional ALD layers in succession, where 2≤n≤10, between the first ALD layer and the second ALD layer, each additional ALD layer ranging from 1-20 nm of additional ALD layers; has a coating layer thickness d21, wherein the one or more additional ALD layers comprise one or more metal oxides selected from the group of HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ , and the one or more additional ALD layers comprises Al ₂ O ₃ , wherein the second ALD consists of one or more metal oxides selected from the group HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅
How to include. According to claim 1,
providing an additional ALD coating layer onto the main sol-gel coating by application of an additional atomic layer deposition process, in which additional metal oxide precursors are Al, Zn, Hf, Ta , Zr, Ti, Sn, Nb, Y, Ga and V, wherein the further ALD coating layer has a further ALD coating layer thickness (d4) in the range of 10-50 nm, The additional ALD coating layer has a chemical composition different from that of the main sol-gel coating layer.
How to further include. 16. The method of claim 15, wherein the additional ALD coating layer comprises two or more layers having different chemical compositions, at least one of the layers being Al ₂ O ₃ , TiO _{2 , ZrO 2 , HfO 2 , SnO 2 , ZnO} and Ta ₂ O ₅ , wherein at least two layers have a chemical composition different from that of the main sol-gel coating layer. The method according to claim 1, wherein the surface of the particulate luminescent material comprises an alkaline earth element, aluminum, and an oxide. 18. The method of claim 17, wherein the alkaline earth element comprises strontium. The particulate luminescent material according to claim 1,
(M1) Li _d Mg _a Al _b N ₄ :Eu (Where 0≤a≤4; 0≤b≤4; 0≤d≤4, and M1 includes at least one from the group consisting of Ca, Sr and Ba and a+b+d=4 and 2a+3b+d=10); and
(M2)Li ₂ Al _2-z Si _z O _2-z N _2+z :Eu (where 0≤z≤0.1, and M2 includes at least one of the group consisting of Sr and Ba)
A method selected from the group consisting of. The method of claim 1 , wherein the particulate luminescent material is selected from the group consisting of (i) SrLiAl ₃ N ₄ :Eu ²⁺ classes and (ii) SrLi ₂ Al _1.995 Si _0.005 O _1.995 N _2.005 :Eu ²⁺ classes. The method according to claim 1, wherein the particulate luminescent material has a number average particle size in the range of 01.-50 μm. A luminescent material comprising luminescent particles obtained by the method according to claim 1 . As a luminescent material,
a particulate luminescent material having a surface;
a primer layer deposited on and in contact with the surface of the particulate light emitting material, the primer layer having a thickness in the range of 0.1-5 nm and comprising a primer layer metal oxide;
As a first ALD layer deposited on and in contact with any part of the surface of the particulate light emitting material not covered with the primer layer and the primer layer, different from the primer layer metal oxide and containing Al, Zn, Hf, Ta, Zr, a first ALD layer comprising a first oxide of at least one of Ti, Sn, Nb, Y, Ga and V;
A second ALD layer deposited on and in contact with the first ALD layer, the second ALD layer comprising Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga different from the first oxide. and a second oxide of at least one of V, wherein the first ALD layer and the second ALD layer form a main ALD layer having a thickness in the range of 5-250 nm; and
A main sol-gel coating layer deposited on the second ALD layer, wherein the main sol-gel coating has a main sol-gel coating layer thickness (d3) in the range of 50-700 nm, and wherein the main sol-gel coating layer is The main sol-gel coating layer having a different chemical composition than the first ALD layer and the second ALD layer.
A light emitting material comprising a. 24. The light emitting material according to claim 23, wherein at least a part of the surface of the particulate light emitting material contains oxide. The luminescent material according to claim 24, wherein at least a part of the surface of the particulate luminescent material contains an alkaline earth element and aluminum. 26. The light emitting material according to claim 25, wherein the alkaline earth element includes strontium. The method of claim 23, wherein the particulate luminescent material,
(M1) Li _d Mg _a Al _b N ₄ :Eu (Where 0≤a≤4; 0≤b≤4; 0≤d≤4, and M1 includes at least one from the group consisting of Ca, Sr and Ba and a+b+d=4 and 2a+3b+d=10); and
(M2)Li ₂ Al _2-z Si _z O _2-z N _2+z :Eu (where 0≤z≤0.1, and M2 includes at least one of the group consisting of Sr and Ba)
A light emitting material selected from the group consisting of. 24. The luminescent material of claim 23, wherein the particulate luminescent material is selected from the group consisting of (i) SrLiAl ₃ N ₄ :Eu ²⁺ classes and (ii) SrLi ₂ Al _1.995 Si _0.005 0 _1.995 N _2.005 :Eu ²⁺ classes. . 24. The method of claim 23, further comprising an additional ALD coating layer disposed on the main sol-gel coating layer, wherein the additional ALD coating layer has an additional ALD coating layer thickness (d4) in the range of 10-50 nm , the additional ALD coating layer has a chemical composition different from that of the main sol-gel coating layer, and the additional ALD coating layer is among Al, Zn, Hf, Ta, Zr, Ti, Sn, Nb, Y, Ga and V A luminescent material comprising one or more one or more oxides. 30. The method of claim 29, wherein the additional ALD coating layer comprises a further multilayer comprising two or more layers having different chemical compositions, one or more of the layers being Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , SnO ₂ , ZnO and Ta ₂ O ₅ , wherein at least two layers have a chemical composition different from that of the main sol-gel coating layer. 24. The method of claim 23, wherein the first ALD layer comprises Al ₂ O ₃ and the second ALD layer comprises one or more metal oxides selected from the group HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ phosphorus luminescent material. 24. The method of claim 23 further comprising n additional ALD layers, wherein 2≤n≤10, between the first ALD layer and the second ALD layer, each additional ALD layer in the range of 1-20 nm. light emitting material having an additional ALD layer coating layer thickness (d21), wherein at least one of the additional ALD layers comprises one or more metal oxides selected from the group of HfO ₂ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ . 24. The light emitting material of claim 23, wherein the primer layer metal oxide comprises SiO ₂ . A lighting device comprising a wavelength converter comprising the light emitting material according to claim 23 and a light source configured to generate source radiation, wherein the wavelength converter is configured to convert at least a portion of the source radiation to wavelength converter light. 35. A lighting device according to claim 34, wherein the particulate luminescent material comprises an alkaline earth aluminate and the wavelength converter comprises a silicone resin. As a display system,
a light emitting diode array comprising a plurality of phosphor converted light emitting diodes, each phosphor converted light emitting diode comprising a wavelength converter comprising the light emitting material of claim 23;
display; and
A lens or lens system positioned to couple light from the light emitting diode array to a display and spaced apart from the light emitting diode array.
Including, display system. As a mobile device,
camera; and
flash lighting system
Including, the flash lighting system,
A light emitting diode array comprising a plurality of light emitting diodes, each light emitting diode comprising a wavelength converter comprising the light emitting material of claim 23 .
To include, a mobile device.

Images