TW202208595A - Light emitting component, a light emitting device and a sheet-like material - Google Patents

Abstract

A light emitting component comprising a light source (10) for emitting blue light (aa), a first layer (1) comprising a red phosphor, and a second layer (2) comprising luminescent crystals (20). Upon absorption of the light emitted by the light source (10), the luminescent crystals (20) emit light of a wavelength in the green light spectrum (cc). The first layer (1) is arranged adjacent to the light source (10). The second layer (2) is arranged remotely from the first layer (1).

Description

Light-emitting component, light-emitting device and sheet material

The present invention relates in a first aspect to a light emitting assembly, in a second aspect to a light emitting device comprising the same, and in a third aspect to a sheet material.

State-of-the-art liquid crystal displays (LCDs) or display components include quantum dot-based components. In particular, the backlight components of such LCDs may include RGB backlights consisting of red, blue, and green lights. Typically today, quantum dot particles are used to generate the backlight color of such backlight assemblies.

The manufacture of such components presents various challenges. One challenge is embedding nanocrystals into components. Due to the different chemical properties of quantum dots, there may be incompatibilities between various embedded materials containing quantum dots or even between quantum dots embedded in the same material. Such incompatibilities can lead to deterioration of materials in the display assembly, which can affect the longevity of such displays.

Light-emitting crystal-based components often deal with stability and brightness challenges, where it is difficult for these components to achieve good stability and high display brightness.

The light conversion factor in this context refers to the ratio between the intensity of green light emitted in a direction perpendicular to the free-standing film and the intensity of blue light that is dissipated (eg, absorbed, reflected, or scattered) in a direction perpendicular to the free-standing film.

A key value for display brightness is transmission haze, which refers to the amount of light that is scattered over a wide angle when light passes through a transparent or partially transparent material (free-standing film in the present invention), which is normally at an off-normal incidence direction of Angles greater than 2.5° (measured with ASTM D1003; eg, with a BYK Gardner hazemeter).

The technical benefit of low haze is the fact that lower haze results in higher display brightness, which is measured as the "light conversion factor" (LCF) of the free-standing film.

The document EP 3 296 378 A1 discloses composite luminescent materials. The composite light-emitting material includes: a host; and perovskite nanoparticles. The perovskite nanoparticles are dispersed in the matrix, wherein the mass ratio of the perovskite nanoparticle matrix to the perovskite nanoparticles is 1:(1-50). The evaporation conditions of the organic solvent system can be controlled to manage the crystallization of the polymer matrix used, the configuration of additives, the nucleation and growth of perovskite nanoparticles. The haze of the material is here mainly defined by the partial crystallization of the polymer used. Haze is here an inherent property of the polymers used.

Therefore, the problem to be solved by the present invention is to provide a light-emitting component which can be manufactured in a manner that avoids the incompatibility of quantum dot materials in the light-emitting component (especially in LCD displays). Furthermore, the present invention overcomes the disadvantages of the prior art in terms of stability and brightness.

The present invention will be described in detail below. It is to be understood that the various implementations, preferences and scopes as provided/disclosed in this specification may be arbitrarily combined. Further, depending on the particular implementation aspect, the selected definition, implementation aspect, or scope may not apply.

Unless otherwise stated, the following definitions shall apply to this specification:

The articles "a", "the" (a, an, the) and similar words used in the context of the present invention are to be read to encompass both the singular and the plural unless otherwise indicated herein or otherwise clearly contradicted by context . The word "containing" shall include all of "comprising", "essentially consisting of", "consisting of". Percentages are given in weight % unless otherwise indicated herein or otherwise clearly contradicted by context. "Independently" means that a substituent/ion may be one selected from the group of said substituents/ion, or may be a combination of more than one of the foregoing.

The term "phosphor" ( LC) is known in the art and relates to materials exhibiting luminescence phenomena, in particular fluorescent materials. Accordingly, red phosphors are materials that exhibit luminescence in the range of 610-650 nm (eg, concentrated around 630 nm). Accordingly, green phosphors are materials that exhibit luminescence in the range of 500-550 nm (eg, concentrated around 530 nm). Typically, phosphors are inorganic particles.

The term "luminescent crystal" ( LC) is known in the art and refers to 3-100 nm crystals made of semiconductor materials. The term includes quantum dots (typically in the range of 2-15 nm) and nanocrystals (typically in the range of more than 15 nm and up to 100 nm, preferably up to 50 nm). Preferably, the luminescent crystals are approximately equiaxed (eg spherical or cubic). A particle is considered approximately equiaxed if the aspect ratio (longest: shortest direction) of all three orthogonal dimensions is 1-2. Accordingly, the combination of LC preferably contains 50-100% (n/n), preferably 66-100% (n/n), more preferably 75-100% (n/n) of equiaxed nanometers crystal.

LC shows luminescence as the word indicates. In the context of the present invention, the term luminescent crystal includes both monocrystalline and polycrystalline particles. In the latter case, a particle may consist of several crystalline regions (grains) connected by boundaries of crystalline or amorphous phases. Luminescent crystals are semiconducting materials that exhibit a direct band gap (typically in the range of 1.1-3.8 eV, more typically 1.4-3.5 eV, even more typically 1.7-3.2 eV). When irradiated with electromagnetic radiation at or above the band gap, valence band electrons are excited to the conduction band leaving holes in the valence band. The formed excitons (electron-hole pairs) are then radiatively recombined in the form of luminescence, with maximum intensity concentrated around the LC bandgap value and exhibiting at least 1% luminescence quantum yield. When exposed to external electron and hole sources, the LC may exhibit electroluminescence.

The term "quantum dot" ( QD) is known and relates especially to semiconductor nanocrystals, which have diameters typically between 2-15 nm. In this range, the physical radius of the QD is smaller than the excited Bohr radius of the whole, so that it is governed by quantum confinement effects. As a result, the electronic state of the QDs and thus the bandgap is a function of the composition and physical size of the QDs, ie the color of absorption/emission is related to the size of the QDs. The optical quality of a QD sample is directly related to its homogeneity (the more monotonically dispersed the QD will have a smaller emission full width at half maximum [FWHM]). When the QDs reach sizes larger than the Bohr radius, quantum confinement effects are hindered and the sample may no longer emit light because the nonradiative pathways for exciton recombination may become dominant. Thus, QDs are a specific subgroup in nanocrystals, which are defined in particular by their size and size distribution.

The term " perovskite crystal " is known and includes especially crystalline compounds of the perovskite structure. Such perovskite structures are known per se and are described as cubic, pseudocubic, tetrahedral, or orthorhombic crystals of the general formula M ¹ M ² X ₃ , where M ¹ is a cation with a coordination number of 12 (truncated half-cube). [cuboctaeder]), M is a cation with coordination number ⁶ (octaeder), and X is an anion in a cubic, pseudocubic, tetrahedral, or orthorhombic lattice position. For these structures, selected cations or anions may be replaced by other ions (randomly or regularly up to 30 atomic %), thereby resulting in doped perovskites or non-integer ratio perovskites while still maintaining their original crystals structure. The manufacture of such luminescent crystals is known, for example, from WO 2018 028869.

The term "polymer" is known and includes both organic and inorganic synthetic materials comprising repeating units, ie "monomers". The term polymer includes both homopolymers and copolymers. Further, cross-linked polymers and non-cross-linked polymers are included. Depending on the context, the term polymer will include its monomers and oligomers. Examples of polymers include acrylate polymers, carbonate polymers, tungsten polymers, epoxy polymers, vinyl polymers, urethane polymers, imide polymers, ester polymers, furan polymers , melamine polymer, styrene polymer, norbornene polymer, polysiloxane polymer and cycloolefin copolymer. As is conventional in the art, polymers may include other materials such as polymerization initiators, stabilizers, fillers, and solvents. The polymers may be further characterized by physical parameters such as polarity, glass transition temperature Tg, Young's modulus and light transmittance.

Transmittance: Typically, polymers used in the context of the present invention are transparent to visible light (ie, non-opaque) to allow the passage of light emitted by the luminescent crystals and light sources that may be used to excite the luminescent crystals. Transmittance may be determined by a white light interferometer or an ultraviolet-visible (UV-Vis) spectrometer.

Glass Transition Temperature: Tg is a well established parameter in the polymer art; it describes the temperature at which an amorphous or semi-crystalline polymer changes from a glassy (hard) state to a softer, compliant or rubbery state. A polymer with a high Tg is considered "hard", while a polymer with a low Tg is considered "soft". At the molecular level, Tg is not a clearly differentiated thermodynamic transfer, but rather a temperature range where the mobility of the polymer chain is significantly increased. However, the convention is to report a single temperature, which is defined as the midpoint of a temperature range bounded by the tangent to the second flat region of the heat flow curve measured by a differential scanning calorimeter (DSC). Tg may be determined according to DIN EN ISO 11357-2 or ASTM E1356 using DSC. This method is particularly suitable if the polymer is in the form of a monolithic material. Alternatively, Tg may be determined according to ISO 14577-1 or ASTM E2546-15 by measuring temperature-dependent micro or nano hardness by micro or nano indentation. This method is suitable for light emitting assemblies and light emitting devices as disclosed herein. Suitable analytical equipment is available as MHT (Anton Paar), Hysitron TI Premier (Bruker) or Nanoindenter G200 (Keysight Technologies). Data obtained by temperature-controlled micro- and nano-indentation can be converted to Tg. Typically, plastic deformation processing, Young's modulus or hardness is measured as a function of temperature, and Tg is the temperature at which these parameters change significantly.

Young's modulus, or modulus of elasticity, is a mechanical property that measures the firmness of solid-state materials. It defines the relationship between stress (force per unit area) and strain (proportional deformation) of a material in the linear elastic range of uniaxial deformation.

The term "scattering particle" is known and includes organic or inorganic particles having a different refractive index than the matrix into which the scattering particles are incorporated. Due to this difference in refractive index, light passing through the matrix will be scattered or diffracted where the individual scattering particles are located. Typical size ranges for scattering particles are 20-20,000 nm, preferably 50-10,000 nm, more preferably 100-5,000 nm. As the word particle implies, nets are excluded. Typically, the scattering particle-solid polymer refractive index difference ΔRI is at least 0.02, preferably 0.1, more preferably 0.2. Typically, the amount of such scattering particles may vary widely, with suitable minimum concentrations being, for example, more than 0.01% by weight, preferably more than 0.1% by weight, and most preferably 1% by weight. A suitable maximum concentration is less than 30% by weight, preferably less than 15% by weight, more preferably less than 8% by weight. In the case of a self-supporting film, it is 50-5000 mg/m ² , preferably 100-1000 mg/m ² , such as 500 mg/m ² .

According to the present invention, the above-mentioned problem is solved by a light emitting device of the first aspect of the present invention, comprising: a light source, a first layer including a red phosphor, and a second layer including a light emitting crystal.

The first layer is disposed adjacent to the light source. The term "layer" refers to the red phosphor or all possible types of how it can be applied to a light source. In particular, if the red phosphor is applied as a film, droplets or individual particles, the application of such red phosphor is covered by the term "layer". In particular, the layers need not be continuous layers and need not be uniform.

In particular, the first layer may further be a combination of quantum dots distributed adjacent to the light source.

The arrangement of the first layer adjacent to the light source means that the first layer is in close contact with the surface of the light source. The red phosphor of the first layer emits light in the red spectrum while absorbing the blue light of the light source. In particular, the red phosphor of the first layer emits light with a wavelength longer than the excitation wavelength of the light source.

The second layer contains light-emitting crystals of a perovskite structure. Upon absorbing the light emitted by the light source, the light emitting crystal emits light having a wavelength in the green spectrum. In particular, the light-emitting crystal of the second layer emits light with a wavelength longer than the excitation wavelength of the light source.

The second layer has a haze h ₂ of 20≦h ₂ ≦70%.

Advantageously, the second layer has a haze h ₂ of 10% < h ₂ < 100%.

Haze in the context of the present invention means transmission haze. Transmission haze is the amount of light that is scattered over a wide angle when light passes through a transparent material (the second layer of the present invention) at angles greater than 2.5° from normal incidence (measured by ASTM D1003; e.g. by BYK gardner haze meter to measure).

The second layer is disposed away from the first layer. Distant in this context especially means that the second layer is configured such that it does not touch the first layer, or that it does not substantially touch the first layer. Distant may further mean that the second layer is arranged parallel to the first layer with a distance therebetween.

In an advantageous embodiment of the invention, the second layer may comprise luminescent crystals, polymers and scattering particles.

In this case, the haze in the second layer is created by scattering particles distributed in the polymer.

Advantageously, the luminescent crystals are embedded in a cross-linked polymer, especially a solid-state cross-linked polymer. Typically, such crosslinked polymers are clear with low haze < 10%.

The haze of crosslinked polymers may be increased by incorporating scattering particles into such polymers.

Advantageously, the light-emitting component comprises a light-emitting crystal, wherein the light-emitting crystal is a compound selected from the group consisting of compounds of formula (II): [M ¹ A ¹ ] _a M ² _b X _c (II), wherein: A ¹ represents one or more organic cations, Preferably ammonium formate, M ¹ represents one or more alkaline earth metals, M ² represents one or more metals other than M ¹ , especially Pb, X represents selected from the group consisting of halides, pseudohalides and sulfides One or more anions of , especially Br, a represents 1-4, b represents 1-2, c represents 3-9, and where M ¹ or A ¹ or M ¹ and A ¹ are present.

Further advantageously, the concentration of Pb is 5-200 mg/m ² , especially 10-100 mg/m ² , more especially 20-80 mg/m ² .

In particular, the first layer is arranged between the light source and the second layer.

In particular, there is an air gap between the second layer and the first layer or the red phosphor, respectively. The gap may also be a vacuum gap or a gap filled with another gas.

In particular, the second layer is arranged parallel to the first layer.

In particular, the second layer is configured such that there is an air gap between the first layer and the second layer, but such that there are support points between the first layer and the second layer to keep the second layer a certain distance from the first layer.

In particular, the second layer is configured such that there is substantially an air gap between the first and second layers, but there may still be points of contact between the first and second layers.

The particular configuration of the one or more light sources, the first layer, and the second layer prevents incompatibilities between their individual materials, especially between the materials of the first and second layers.

For an advantageous embodiment, the light source, the first layer and the second layer are arranged in this order in vertical alignment.

In particular, the second layer may be arranged away from more than one light source and/or more than one first layer.

In particular, the second layer may be arranged away from more than one light source, wherein each light source includes its respective first layer adjacent to the respective light source.

In an advantageous embodiment of the present invention, the second layer has a haze h ₂ of h ₂ ≦80%, preferably ≦70%, and most preferably ≦60%.

In another advantageous embodiment of the present invention, the second layer has a haze h ₂ of 10≦h ₂ ≦80%, preferably 20≦h ₂ ≦70%, and most preferably 30≦h ₂ ≦60%.

The technical benefit of the low haze of the second layer is that the luminescent perovskite crystals in the second layer are more stable, especially if they are exposed to a blue light source. The stability is a result of reduced blue light multiple scattering in the second layer due to lower haze.

Furthermore, a further technical benefit of low haze is the fact that lower haze results in higher display brightness, which is measured as the "light conversion factor" (LCF) of the second layer. The light conversion factor of the second layer refers to the ratio between the intensity of green light emitted in a direction perpendicular to the second layer and the intensity of blue light that is dissipated (eg absorbed, reflected or scattered) in a direction perpendicular to the second layer.

In a further advantageous embodiment of the present invention, the red phosphor is selected from one or more core-shell quantum dots and/or is based on In or Cd, preferably based on InP or CdSe, respectively. The shell typically contains ZnS or ZnSeS.

In a further advantageous embodiment of the present invention, the core-shell quantum dots have a platelet structure. Preferably, such platelet structure points are based on CdSe.

In a further advantageous embodiment of the invention, the core-shell quantum dots comprise CdSe cores doped with Zn. This doping, sometimes called alloying, reduces the amount of Cd per quantum dot.

Advantageously, the red phosphor is a Mn ⁴⁺ doped phosphor of formula (I): A _x [MF _y ]: Mn ⁴⁺ (I), where: A represents Li, Na, K, Rb, Cs or Its combination, M represents Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd or their combination, x represents the absolute value of the charge of [MF _y ] ions and y represents 5, 6 or 7, in particular, wherein the red phosphor of formula (I) is K ₂ SiF ₆ :Mn ⁴⁺ .

In a further advantageous embodiment of the light-emitting device, the perovskite light-emitting crystal is selected from the compounds of formula (II): [M ¹ A ¹ ] _a M ² _b X _c (II), wherein: A ¹ represents one or more Organic cation, preferably ammonium formate (FA), M ¹ represents one or more alkaline earth metals, M ² represents one or more metals other than M ¹ , especially Pb, X represents selected from halides, pseudohalides and sulfides One or more anions of the group consisting of, especially Br, a for 1-4, b for 1-2, c for 3-9, and in which M ¹ or A ¹ or M ¹ and A ¹ are present.

In particular, formula (II) describes perovskite luminescent crystals that emit light in the green spectrum with wavelengths between 500 nm and 550 nm, especially concentrated around 527 nm, when absorbing light emitted by a light source.

In particular, formula (II) describes luminescent crystals, in which X represents a halide or pseudohalide, such as Br, Cl, CN, especially Br.

In particular, formula (II) describes a luminescent crystal, wherein M ² represents Pb.

In particular, formula (II) describes a luminescent crystal, in which A ¹ represents FA (ammonium formate) and M ¹ is absent.

Advantageously, the luminescent crystals are further embedded in the solid polymer . Particularly suitable polymers are those whose repeat units satisfy the following: (O atoms + N atoms)/(C atoms) < 0.9. Preferably, this value is < 0.4, more preferably < 0.3, and most preferably < 0.25.

In a further advantageous embodiment, the solid polymer comprises an acrylate. Most preferably, the polymer comprises or consists of repeating units selected from the group of cycloaliphatic acrylates (monofunctional acrylates).

In another advantageous embodiment, the solid polymer is cross-linked and comprises polyfunctional acrylates in addition to monofunctional acrylates.

In a further advantageous embodiment, the solid polymer has a glass transition temperature Tg of Tg≦120°C (preferably Tg≦100°C, most preferably Tg≦80°C, most preferably Tg≦70°C). The respective Tg was measured according to DIN EN ISO 11357-2: 2014-07 during the second heating cycle using a heating rate of 20 K/min, starting from -90°C until 250°C.

In a further advantageous embodiment, the solid polymer is constructed as a sheet polymer. The sheet-like polymer may have the shape of a polymeric film, and the film thickness is typically 0.001-10 mm, most typically 0.01-0.5 mm. Sheet polymers may be continuous and flat or discontinuous, eg, having a microstructure (eg, prismatic).

In a further advantageous embodiment, the solid polymer is sandwiched between the two barrier layers . In particular, this sandwich arrangement refers to an arrangement in the horizontal direction of the barrier layer, the polymer and the other barrier layer. The two barrier layers of the sandwich structure can be made of the same barrier layer material or different barrier layer materials.

The technical efficacy of the barrier layer is to improve the stability of the luminescent perovskite crystal, especially against oxygen or moisture.

In particular, such barrier layers are known in the art; typically comprising materials with low water vapor transmission rate (WVTR) and/or low oxygen transmission rate (OTR) /Material combination. By selecting such materials, degradation of the LC in the device in response to exposure to moisture and/or oxygen is reduced or even avoided. The barrier layer or film preferably has a WVTR < 10 g/(m ² *day) at atmospheric pressure, temperature 40°C/relative humidity 90%, more preferably less than 1 g/(m ² *day), best is less than 0.1 g/(m ² *day).

In one embodiment, the barrier film may be permeable to oxygen. In an alternative optional implementation, the barrier membrane is impermeable to oxygen and has an OTR (oxygen transmission rate) < 10 mL/(m ² *day) at atmospheric pressure, temperature 23°C/relative humidity 90%, More preferably < 1 mL/(m ² *day), most preferably < 0.1 mL/(m ² *day).

In one embodiment, the barrier film is transparent, that is, the visible light transmittance is > 80%, preferably > 85%, and most preferably > 90%.

A suitable barrier film may be in the form of a single layer. Such barrier films are known in the art and contain glasses, ceramics, metal oxides and polymers. Suitable polymers may be selected from the group consisting of polyvinylidene chloride (PVdC), cyclic olefin copolymer (COC), ethylene vinyl alcohol (EVOH), high density polyethylene (HDPE) and polypropylene (PP) ; Suitable inorganic materials may be selected from the group consisting of metal oxides, SiOx, SixNy and AlOx. Most preferably, the polymeric moisture barrier material comprises a material selected from the group of PVdC and COC.

Most advantageously, the polymeric oxygen barrier material comprises a material selected from EVOH polymers.

Suitable barrier films may be in the form of multiple layers. Such barrier films are known in the art and generally comprise: a substrate, such as polyethylene terephthalate (PET) with a thickness in the range of 10-200 μm; an inorganic thin layer comprising one selected from SiOx and AlOx group of materials; either an organic layer based on liquid crystal embedded in a polymer matrix, or an organic layer of a polymer with the desired barrier properties. Possible polymers for such an organic layer include, for example, PVdC, COC and EVOH.

In a further advantageous embodiment of the invention, a diffusing film or diffusing plate is arranged between the first layer and the second layer.

In a further advantageous embodiment of the present invention, the light guide plate and the diffusing film are arranged between the first layer and the second layer of the present invention. Advantageously, the light emitted from the light source and the first layer enters the light guide plate at an angle of 90° with respect to the light emitted by the light guide plate to the diffusing film and finally excites the light emitting crystals in the second layer.

In a further advantageous embodiment of the present invention, the diffusing sheet is arranged between the first layer and the second layer of the present invention. Advantageously, the light emitted from the light source and the first layer enters the diffuser plate at an angle of 0° with respect to the light emitted by the light guide plate to the diffuser plate and finally excites the luminescent crystals in the second layer.

A second aspect of the present invention is a light emitting device comprising the light emitting assembly according to the first aspect. In particular, such a light-emitting device is a liquid crystal display (LCD).

In an advantageous embodiment of the invention, the light-emitting component of the light-emitting device comprises an array of more than one light source, wherein each light source has a respective adjacent first layer disposed adjacent to a particular light source, so that an array of light sources is formed with its individual first floor. The second layer is configured away from the array. The second layer is configured such that an air gap is formed between the first layer and the second layer of the array. The array basically covers the entire liquid crystal display area.

In an advantageous embodiment, each light source in an array of one or more light sources is covered by a respective adjacent first layer, thus creating an array with an individual light source and its respective adjacent first layer.

Advantageously, the second layer may be formed in a single piece to cover one or more light sources and at least part of the array or the entire array of individual light sources in their respective adjacent arrays of the first layer, wherein the second layer is arranged away from the individual light sources and an array of its individual first layers.

In another advantageous embodiment, the second layer may be formed by a multi-layer piece covering at least a partial or complete array of the light source and its respective first layer, wherein all the multi-layer pieces of the second layer are arranged away from the light source and An array of its individual first layers.

In a further advantageous embodiment of the invention, the one or more light sources in the array are each adapted to switch on and off at a frequency f of f≧150 Hz, preferably f≧300 Hz, most preferably f ≧600Hz.

A third aspect of the present invention is a free-standing film comprising a light-emitting crystal. The luminescent crystals are of a perovskite structure and emit green and/or red light in response to photoexcitation with a wavelength shorter than the emitted light. The free-standing film has a haze h ₂ of 20≦h ₂ ≦70%, preferably h ₂ < 80%, preferably < 70%, and most preferably < 60%.

In another advantageous embodiment of the present invention, the free-standing film has a haze h ₂ (measured by a BYK gardner haze meter) of 10≦h ₂ ≦80%, preferably 30≦h ₂ ≦60%.

In another advantageous embodiment of the invention, the free-standing film has a transmittance (measured with a BYK gardner haze meter) of >75%, preferably >85%, and most preferably >90%.

In an advantageous embodiment of the present invention, the luminescent crystal is characterized in that the luminescent crystal is embedded in a cross-linked polymer, especially a solid-state cross-linked polymer.

In a further advantageous embodiment of the present invention, the luminescent crystal is selected from compounds of formula (II): [M ¹ A ¹ ] _a M ² _b X _c (II), wherein: A ¹ represents one or more organic cations, more It is preferably ammonium formate (FA), M ¹ represents one or more alkaline earth metals, M ² represents one or more metals other than M ¹ , especially Pb, X represents selected from the group consisting of halides, pseudohalides and sulfides One or more anions of the group, especially Br, a stands for 1-4, b stands for 1-2, c stands for 3-9, and where M ¹ or A ¹ or M ¹ and A ¹ are present.

Further advantageously, M ² represents Pb and the concentration of Pb is 5-200 mg/m ² , especially 10-100 mg/m ² , more especially 20-80 mg/m ² .

In another advantageous embodiment of the present invention, the free-standing film includes scattering particles, which are preferably selected from polymeric compositions, and most preferably selected from organopolysiloxanes.

Typical size ranges for scattering particles are 20-20,000 nm, preferably 50-10,000 nm, more preferably 100-5,000 nm. Typically, the amount of such scattering particles may vary widely, with suitable minimum concentrations being, for example, more than 0.01% by weight, preferably more than 0.1% by weight, and most preferably 1% by weight. A suitable maximum concentration is less than 30% by weight, preferably less than 15% by weight, more preferably less than 8% by weight. In the case of a self-supporting film, it is 50-5000 mg/m ² , preferably 100-1000 mg/m ² , such as 500 mg/m ² .

In a further advantageous embodiment of the self-standing membrane, the solid polymer is the polymer referred to in the first aspect of the present invention.

Advantageously, such polymers comprise acrylates, in particular comprise or consist of repeating units selected from the group of cycloaliphatic acrylates, in particular, and/or wherein the acrylates comprise monofunctional acrylic acid esters Repeating units of ester monomers and multifunctional acrylate monomers.

In a further advantageous embodiment, the solid polymer is characterized by a molar ratio of the sum of (oxygen + nitrogen) to carbon of < 0.9, preferably < 0.4, preferably < 0.3, most preferably < 0.25.

In a further advantageous embodiment, the solid polymer has a glass transition temperature Tg of Tg≦120°C (preferably Tg≦100°C, most preferably Tg≦80°C, most preferably Tg≦70°C); whereby each Tg is measured according to DIN EN ISO 11357-2:2014-07 during the second heating cycle, applying a heating rate of 20 K/min, starting from -90°C until 250°C.

Furthermore, in an advantageous embodiment, the polymer may be a sheet polymer.

In a further advantageous embodiment, the polymer is sandwiched between the two barrier layers.

Advantageously, the free-standing film comprises light-emitting crystals that emit red light in response to excitation by light having a wavelength shorter than that of the emitted light.

A fourth aspect of the present invention is a light emitting device, especially a liquid crystal display (LCD), comprising the free-standing film according to the third aspect.

Other advantageous implementation aspects are listed in the appendix and described below.

Embodiments, examples, and examples representing or deriving aspects, aspects, and advantages of the present invention will be better understood from the following detailed description of the invention. This description refers to the accompanying drawings, in which:

Figure 1a shows a schematic diagram of an assembly comprising a light source 10 emitting blue light aa and a first layer 1 comprising a red phosphor emitting red light bb. Advantageously, the red phosphor particles of the red layer 1 are selected from core-shell CdSe QDs, core-shell InP QDs and KSF phosphors (K ₂ SiF ₆ : Mn ⁴⁺ ). Upon absorbing blue light aa, the red phosphor emits light bb in the red spectrum.

In particular, the assembly shown in FIG. 1 b shows the arrangement of the light source 10 and the first layer 1 adjacent to the light source 10 . In this schematic diagram, the first layer 1 contains red phosphor particles, which are distributed adjacent to the light source 10 .

FIG. 1 b shows a schematic diagram of a light-emitting device according to an advantageous embodiment of the present invention. The light emitting component includes a light source 10 emitting blue light, a first layer 1 including a red phosphor, and a second layer 2 including a light emitting crystal 20 . The red phosphor of the first layer 1 emits light bb in the red spectrum while absorbing the blue light aa. The first layer 1 is arranged adjacent to the light source 10 . The light-emitting crystal 20 of the second layer 2 has a perovskite structure. While absorbing the light emitted by the light source 10, the light emitting crystal 20 emits light cc having a wavelength in the green spectrum. The second layer 2 has a haze h ₂ of 10%≦h ₂ ≦100%. The second layer 2 is arranged away from the first layer 1 . In particular, there is an air gap between the second layer 2 and the first layer 1 .

In a further advantageous implementation, the light-emitting device of FIG. 1b may have a haze h ₂ of 20≦h ₂ ≦70%, preferably h ₂ ≦80%, preferably h ₂ ≦70%, and most preferably h ₂ ≦60%.

Advantageously for this embodiment, the red phosphor is selected from one or more core-shell quantum dots based on In or Cd, in particular based on InP(III) or CdSe(IV), respectively.

Further advantageously, the red phosphor is a Mn ⁴⁺ doped phosphor of formula (I) as described above. Examples of such embodiments are disclosed in <Experimental Section> (Example 1).

In a further advantageous embodiment of FIG. 2, the luminescent crystal 20 is selected from the compounds of formula (II) as disclosed above. Examples of such embodiments are disclosed in <Experimental Section> (Example 2).

In a further advantageous embodiment, the luminescent crystal 20 is selected from compounds of formula (II), wherein M ² is Pb and wherein the concentration of Pb is 5-200 mg/m ² , especially 10-100 mg/m ² , More particularly 20-80 mg/m ² .

Advantageously, the luminescent crystals 20 are embedded in a solid polymer, especially wherein the polymer comprises an acrylate, more particularly wherein the polymer comprises a cycloaliphatic acrylate (monofunctional acrylate).

In another advantageous embodiment, the solid polymer is cross-linked and comprises polyfunctional acrylates in addition to monofunctional acrylates.

Such polymers may be further constructed into sheet polymers.

In a further advantageous embodiment, the polymer may be sandwiched between barrier layers 21 . An example of such a barrier layer 21 is shown in Figure 1c.

In a further advantageous embodiment, the solid polymer has a glass transition temperature Tg of Tg≦120°C (preferably Tg≦100°C, most preferably Tg≦80°C, most preferably Tg≦70°C).

In a further advantageous embodiment, the second layer may comprise scattering particles embedded in a solid polymer, which are used, inter alia, to generate the haze (scattering particles not shown).

FIG. 1 c shows a schematic diagram of an embodiment of the self-supporting film 200 . The free-standing film includes light-emitting crystals 20 embedded in a polymer, wherein the light-emitting crystals 20 are perovskite structures and emit green light cc and/or red light bb in response to light excitation with wavelengths shorter than the emitted light, and wherein the free-standing film Has a haze h ₂ of 20≦h ₂ ≦70%, preferably h ₂ < 80%, especially h ₂ < 70%, more especially h ₂ < 60%.

Advantageously, the free-standing film 200 comprises scattering particles (scattering particles not shown) embedded in a polymer.

In a further embodiment, the light-emitting crystals 20 of the free-standing film 200 are embedded in a cross-linked solid polymer.

In a further advantageous embodiment, the luminescent crystal 20 is selected from compounds of formula (II).

In a further advantageous embodiment, the luminescent crystal 20 is selected from compounds of formula (II), wherein M ² is Pb and wherein the concentration of Pb is 5-200 mg/m ² , especially 10-100 mg/m ² , More particularly 20-80 mg/m ² .

In a further advantageous embodiment, the solid polymer comprises an acrylate, in particular comprises or consists of repeating units selected from the group of cycloaliphatic acrylates, in particular, and/or wherein the acrylate comprises a repeat unit selected from the group of cycloaliphatic acrylates. Repeating units of monofunctional acrylate monomers and multifunctional acrylate monomers.

In a further advantageous embodiment of the self-standing membrane 200, the solid polymer is characterized by a sum of (oxygen + nitrogen) to carbon molar ratio of < 0.9, preferably < 0.4, preferably < 0.3, and most preferably < 0.25.

In a further advantageous embodiment, the solid polymer has a glass transition temperature Tg of Tg≦120°C, especially Tg≦100°C, especially Tg≦80°C, especially Tg≦70°.

In a further advantageous embodiment, the solid polymer is constructed as a sheet-like polymer, and/or wherein the solid polymer is sandwiched between the two barrier layers 21 .

FIG. 2 shows a schematic diagram of a further implementation of the light-emitting device. The light emitting component includes a light source 10 emitting blue light, a first layer 1 including a red phosphor, and a second layer 2 including a light emitting crystal 20 . The red phosphor of the first layer 1 emits light bb in the red spectrum while absorbing the blue light aa. The first layer 1 is arranged adjacent to the light source 10 . The light-emitting crystal 20 of the second layer 2 has a perovskite structure. While absorbing the light emitted by the light source 10, the light emitting crystal 20 emits light cc having a wavelength in the green spectrum. The second layer 2 has a haze h ₂ of 40%≦h ₂ ≦90%. The second layer 2 is arranged away from the first layer 1 . In particular, there is an air gap between the second layer 2 and the first layer 1 .

In this embodiment, not only one but a plurality of light sources 10 and their respective first layers 1 are arranged in an array, wherein the second layer 2, which is the second layer 2 of all the light sources 10 and their respective first layers 1, forms a pieces.

All the advantageous features disclosed in Fig. 1b can also be combined with the embodiment of Fig. 1c.

Figure 3 shows a schematic diagram of light emitting components used in certain backlight architectures, especially LCD displays. In addition to the schematic diagram of FIG. 2 , a diffuser plate 3 is disposed between the first layer 1 and the second layer 2 .

Figure 4 shows a further schematic diagram of a further light emitting device for a particular backlight architecture, especially an LCD display. The device comprises a light emitting component having a light source 10 emitting blue light aa, a first layer 1 comprising a red phosphor, and a second layer 2 comprising a light emitting crystal 20 . The first layer 1 is arranged adjacent to the light source 10 . The second layer 2 is arranged away from the first layer 1 . A diffusing film 3 and a light guide plate (LGP) 4 are disposed between the first layer 1 and the second layer 2 . In particular, the light source 10 and the first layer 1 are configured such that the blue light aa and the red light bb enter the LGP 4 at a 90° angle with respect to light emitted by the LGP 4 exciting the light emitting crystal 20 of the second layer 2 . In any event, the light source 20 may be configured in another advantageous embodiment such that the light enters the LGP at an angle of 0°.

5 discloses a schematic diagram of an advantageous light-emitting device according to an embodiment of the present invention. A light-emitting device (especially a liquid crystal display) includes light-emitting components, such as shown in one of the embodiments in FIGS. 1 to 4 .

An advantageous lighting device comprises a lighting assembly comprising an array of one or more, in particular more than one, light sources 10 . Each light source 10 includes a respective first layer 1 arranged adjacent to the light source 10 . Furthermore, this embodiment includes a second layer 2 which is arranged away from the array. In particular, the array covers substantially the entire liquid crystal display area 5 .

A further advantageous lighting device comprises one or more light sources 10 in an array, wherein each light source 10 is adapted to be switched on and off with a frequency f of f≧150 Hz, especially f≧300 Hz, more particularly f≧ 600Hz.

Fig. 6a shows the emission spectrum of the embodiment of the light emitting device schematically shown in Fig . 6b according to the present invention. The light emitting assembly comprises a plurality of light sources 10 emitting blue light aa, each light source comprising a respective first layer 1 comprising a red phosphor and, upon absorbing the blue light aa, the red phosphor emitting light bb in the red spectrum. The red phosphors are arranged adjacent to the individual light sources 10 .

As shown in FIG. 7b , the second layer 2 including the light emitting crystals 20 is arranged away from the plurality of light sources 10 and their respective first layers 1 . While absorbing the light emitted by the light source 10, the light emitting crystal 20 emits light cc having a wavelength in the green spectrum. The second layer 2 has a haze: 10% < h ₂ < 100%.

Accordingly, the emission spectrum of the light-emitting device shown in FIG. 7a shows sharp peaks in the range of blue, green and red visible light. <Experimental part> [ Example 1 : Production of a backlight unit for an LCD display using the components described herein]

Figure 6b shows a schematic diagram of the assembly in an array, the emission spectra of which were measured as shown in Figure 6a . The assembly of Figure 6b comprises a light source 10 emitting blue light aa and a first layer 1 comprising a red phosphor emitting red light bb. Advantageously, the red phosphor particles of the red layer 1 are selected from core-shell CdSe QDs, core-shell InP QDs and KSF phosphors (K ₂ SiF ₆ : Mn ⁴⁺ ). Upon absorbing blue light aa, the red phosphor emits light bb in the red spectrum.

The component's emission spectrum shows spikes in the blue and red ranges of the visible spectrum.

In particular, the assembly shown in FIG. 6b shows the arrangement of the light source 10 and the first layer 1 adjacent to the light source 10 . In this schematic diagram, the first layer 1 contains red phosphor particles, which are distributed adjacent to the light source 10 .

To measure the data, a two-dimensional (2D) array of 200 individual LEDs was used, whereby the LEDs consisted of a blue-emitting gallium nitride wafer and red-emitting core-shell cadmium selenide quantum dots, the latter deposited directly on the blue LED wafer (on-wafer) . The emission spectrum of this LED array is shown in Figure 6a. [ Example 2 ]

The array from Example 1 was taken and a diffuser plate 3 was additionally placed on top of the array of light sources and their respective first layers adjacent to the individual light sources. The diffuser plate is used to uniformly distribute the light generated by the LEDs, similar to the lighting assembly shown in FIG. 3 .

In addition, the green away perovskite QD film (free-standing film according to Example 3) was placed on top of the diffuser plate (only loosely placed; no glue or the like). A two-crossed prismatic film (crossed BEF) and a brightness enhancement film (DBEF) were then placed on top of the green perovskite film (not shown). The emission spectrum of the entire backlight structure was measured with a spectrometer (Konica Minolta CS-2000) to show blue, red and green emission peaks, as shown in Figure 7a. [ Example 3 : The green perovskite QD film was prepared as a free-standing film with low haze h ₂ and low Tg according to the third aspect of the present invention]

Green perovskite QDs composed of lead tribromide ( _FAPbBr3 ) were synthesized in toluene as follows: PbBr2 and FABr _were ground to synthesize lead tribromide ( _FAPbBr3 ). That is, 16 mmol of PbBr2 (5.87 g, 98% ABCR, Karlsruhe (Germany)) and 16 mmol of FABr ( _2.00 g, Greatcell Solar Materials, Queanbeyan (Australia)) yttrium-stabilized zirconia beads (diameter 5 mm) milled for 6 hours to obtain pure cubic _FAPbBr3 , which was confirmed by X-ray diffractometry (XRD). Orange _FAPbBr3 powder was added to oleylamine (80-90, Acros Organics, Geel (Belgium)) (weight ratio _FAPbBr3 :oleylamine=100:15) and toluene (purity >99.5%, Sigma Aldrich). The final concentration of FAPbBr ₃ was 1% by weight. The mixture was then ball-milled for 1 hour under ambient conditions (atmospheric conditions for all experiments: 35°C, 1 atm, in air) using yttrium-stabilized zirconia beads of 200 μm diameter size for 1 hour. Green ink.

Film formation : In an accelerated mixer, 0.1 g of green ink was mixed with a UV-hardenable monomer/crosslinker mixture (0.7 g of FA-513AS, Hitachi Chemical, Japan/0.3 g of Miramer M240, Miwon, Korea), which Contains 1 wt % of the photoinitiator diphenyl(2,4,6-tritolyl) phosphine oxide (TCI Europe, The Netherlands) and 2 wt % of polymeric scattering particles (organopolysiloxane, ShinEtsu, KMP -590) and toluene was evaporated under vacuum (< 0.01 mbar) at room temperature. The resulting mixture contained 500 ppm of Pb, as measured by inductively coupled optical emission spectroscopy (ICP-OES), and was then coated on a 100-micron barrier film (supplier) at a layer thickness of 50 microns. : I-components (Korea); Product: TBF-1007), and then a second barrier film of the same type was laminated. Afterwards, the laminate was UV hardened for 60 seconds (UVAcube 100 equipped with a mercury lamp and a quartz filter, Hoenle, Germany). When placed on an LED blue light source (emission wavelength 450 nm) with two crossed prism sheets (X-BEF) and a brightness enhancement film (DBEF) on a QD film (optical properties were measured with Konica Minolta CS-2000), just obtained The initial performance of the green perovskite QD film shows an emission wavelength of 526 nm, a FWHM of 22 nm, a color coordinate in the Y direction (“y value”, CIE1931) y = 0.15. The haze of the obtained QD film was 50% and the transmittance was 85% (measured with a Byk Gardner hazemeter). The light conversion factor (LCF; LCF = reduction in emitted green intensity (integrated emission peak) divided by blue intensity (integrated emission peak)) was measured using a Konica Minolta CS-2000 as the vertical emission of green and blue light from QD films.

The glass transition temperature Tg of the UV-curable resin composition is determined by DSC according to DIN EN ISO 11357-2:2014-07, the start temperature is -90°C, the end temperature is 250°C, and nitrogen atmosphere (20 ml/min) The heating rate in 20 K/min. The purge gas was nitrogen (5.0) at 20 ml/min. The DSC system used was a DSC 204 F1 Phoenix (Netzsch). The Tg was determined on the second heating cycle (the first heating from -90°C to 250°C showed overlapping effects in addition to glass transfer). For DSC measurements, the UV-cured resin composition was removed from the QD film by peeling off the barrier film. The measured Tg of the UV-curable resin composition was 75°C.

The stability of the QD film was tested under LED blue light irradiation for 1,000 hours by placing the QD film in a light box with high blue intensity (supplier: Hoenle; model: LED CUBE 100 IC), blue pass on the QD film The amount was 220 mW/cm ² and the QD film temperature was 50°C. The change in optical parameters of the QD films after 1,000 hours of flux testing was measured using the same procedure as (previously) to measure the initial efficacy. The optical parameters were changed as follows: • Change of y value: from 0.15 to 0.119 (-0.031) • Change of LCF: from 50% to 40% (-10%) • Change of green emission wavelength: from 526 nm to 525 nm ( -1 nm) • Change of green FWHM: 0 nm

Similar results _were obtained when _FAPbBr3 was replaced by [CsFA]PbBr3. Such perovskites are described in document WO 2018/028869 A1, eg example 10. [ Comparative Example 1 to Example 3 : Preparation of Green-away Perovskite QD Films with High Haze and Low Tg]

The procedure is the same as the previous procedure for the low haze QD film, with the exception of changing the following parameters: • The Pb content of the entire UV-hardenable acrylate blend was 200 ppm. • 12 wt% scattering particles KMP-590 were mixed into the UV curable acrylate blend to increase the haze of the final QD film.

The freshly obtained green perovskite QD film showed an emission wavelength of 525 nm, a FWHM of 22 nm, and a y value of 0.149 (almost the same as the low haze QD film of Example 3). The LCF of the QD film was 43%. The haze of the QD film was 98% and the transmittance was 81%. The measured Tg of the UV-curable resin composition was 77°C. It can be seen that the LCF is lower than in Example 3. Higher haze results in lower LCF, and lower haze results in higher LCF. Thus, the lower haze of the QD film is beneficial for having higher LCF and in turn higher display efficiency (at a certain comparable white point color coordinate).

The optical parameters of the QD films after 1,000 hours of flux testing changed as follows: • Change in y value: from 0.149 to 0.058 (-0.091) • Change in LCF: from 43% to 14% (-29%) • Change in green emission wavelength: from 525 nm to 521 nm (-4 nm) • Green FWHM change: 0 nm

These results show that the higher haze of the QD film results in a lower QD film stability at high blue flux compared to Example 3 (specifically, the y value, LCF, emission wavelength are all less stable). Thus, it would be advantageous to have QD films with low haze, which result in improved QD film stability at high blue flux, in order to have stable color coordinates and stable white point over the operational life of the display device. [ Comparative Example 2 to Example 3 : Preparation of Green-away Perovskite QD Films with Low Haze and High Tg]

The procedure was the same as that of Example 3, except that the acrylate monomer mixture (0.7 g of FA-513AS, Hitachi Chemical, Japan/0.3 g of Miramer M240, Miwon, Korea) was replaced with the following acrylate monomer mixture: • 0.7 g of FA-DCPA, Japan Hitachi Chemical / 0.3 g of FA-320M, Japan Hitachi Chemical.

The freshly obtained green perovskite QD film showed an emission wavelength of 526 nm, a FWHM of 22 nm, a y value of 0.153 (almost the same as the low haze QD film of Example 3). The LCF of the QD film was 49%. The haze of the QD film was 51% and the transmittance was 85%. The measured Tg of the UV-curable resin composition was 144°C.

The optical parameters of the QD films after 1,000 hours of flux testing changed as follows: • Change of y value: from 0.153 to 0.068 (-0.085) • Change in LCF: from 49% to 21% (-28%) • Change in green emission wavelength: from 526 nm to 525 nm (-1 nm) • Green FWHM change: 0 nm

These results show that the high Tg solid state polymer of the QD membrane (free-standing membrane) results in a lower stability of the QD membrane at high blue flux. It would thus be advantageous to have a QD film with a low Tg, which results in improved stability of the QD film at high blue flux, so as to have stable color coordinates and stable white point over the operational lifetime of the display device.

1: first floor 2: second floor 3: Diffuser plate 4: Light guide plate 5: LCD display area 10: Light source 20: Luminous crystals 21: Barrier layer 200: Self-supporting film aa: Blu-ray bb: red light cc: green light

The invention will be better understood and matters not listed above will become apparent from the following detailed description of the invention. This description refers to the accompanying drawings, in which: [ FIG. 1 a ] A schematic diagram showing a light source for emitting blue light having a first layer including a red phosphor; [FIG. 1b] A schematic diagram showing a light-emitting device according to an advantageous embodiment of the present invention; [FIG. 1c] A schematic diagram showing a free-standing film according to an embodiment of the present invention; [FIG. 2] A schematic diagram showing a light-emitting component according to a further advantageous embodiment of the present invention; [FIG. 3] A schematic diagram showing a light-emitting component according to a further advantageous embodiment of the present invention; [FIG. 4] A schematic diagram showing a light-emitting component according to a further advantageous embodiment of the present invention; [FIG. 5] shows a light-emitting device according to an advantageous embodiment of the present invention; [Fig. 6a] shows the emission spectrum of the device shown schematically in [Fig. 6b]; and [Fig. 7a] shows the emission spectrum of the device shown schematically in [Fig. 7b].

1: first floor

10: Light source

aa: Blu-ray

bb: red light

Claims (24)

A light emitting assembly comprising: - a light source (10) emitting blue light (aa), - a first layer (1) comprising a red phosphor, • wherein upon absorbing the blue light (aa) the red phosphor Light (bb) emitting in the red spectrum, and • wherein the first layer (1) is arranged adjacent to the light source (10), - a second layer (2) comprising a luminescent crystal ( 20), solid polymer and scattering particles, • wherein the luminescent crystal (20) is a perovskite structure, • wherein when absorbing the light emitted by the light source (10), the luminescent crystal (20) emits a wavelength of The green spectrum light (cc), • wherein the luminescent crystal (20) and the scattering particles are embedded in the solid polymer, • wherein the second layer (2) has a haze of 20≦h ₂ ≦70% h ₂ , and - wherein the second layer (2) is disposed away from the first layer (1). The light-emitting assembly of claim 1, wherein the light-emitting crystal is embedded in a cross-linked solid-state polymer. A light emitting assembly comprising: - a light source (10) emitting blue light (aa), - a first layer (1) comprising a red phosphor, • wherein upon absorbing the blue light (aa) the red phosphor Light (bb) emitting in the red spectrum, and • wherein the first layer (1) is arranged adjacent to the light source (10), - a second layer (2) comprising a luminescent crystal ( 20) and a cross-linked solid state polymer, • wherein the luminescent crystal (20) is a perovskite structure, • wherein when absorbing the light emitted by the light source (10), the luminescent crystal (20) emits a wavelength of The green spectrum light (cc), • wherein the luminescent crystal (20) is embedded in the cross-linked solid polymer, • wherein the second layer (2) has a haze h of 20≦h ₂ ≦70% ₂ , - wherein the second layer (2) is arranged away from the first layer (1). The light-emitting assembly according to any one of claims 1 to 3, wherein the light-emitting crystal (20) is a compound selected from the group consisting of compounds of formula (II): [M ¹ A ¹ ] _a M ² _b X _c (II), wherein: A ¹ represents one or more organic cations, preferably ammonium formate, M ¹ represents one or more alkaline earth metals, M ² represents one or more metals other than M ¹ , especially Pb, X represents selected from halides, pseudohalides and one or more anions of the group consisting of sulfides, especially Br, a for 1-4, b for 1-2, c for 3-9, and in which M ¹ or A ¹ or M ¹ and A ¹ are present . A light-emitting assembly as claimed in claim 4, • wherein M ² represents Pb, • wherein the concentration of Pb is 5-200 mg/m ² , especially 10-100 mg/m ² , more especially 20-80 mg/m ² . The light-emitting component of any of the preceding claims, wherein the red phosphor is selected from one or more core-shell quantum dots based on In or Cd, especially based on InP(III) or CdSe(IV), respectively. The light-emitting assembly of any one of claims 1 to 5, wherein the red phosphor is a Mn ⁺⁴ doped phosphor of formula (I): [A] _x [MF _y ]: Mn ⁴⁺ (I), Where: A represents Li, Na, K, Rb, Cs or a combination thereof, M represents Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd or its In combination, x represents the absolute value of the charge of the [MFy] ion; and _y represents 5, ₆ or 7, preferably (I") _K2SiF6 :Mn4 ⁺ (I"). The light-emitting component of any of the preceding claims, wherein the solid polymer comprises acrylates, in particular comprises or consists of repeating units selected from the group of cycloaliphatic acrylates, in particular, and/or wherein the acrylate comprises repeating units selected from monofunctional acrylate monomers and multifunctional acrylate monomers. A light-emitting assembly as claimed in any preceding claim, wherein the solid polymer is characterized by a sum of (oxygen + nitrogen) to carbon molar ratio of < 0.9, preferably < 0.4, preferably < 0.3, most Preferably < 0.25. The light-emitting assembly of any one of the preceding claims, wherein the solid polymer has a glass transition temperature Tg of Tg≦120°C, especially Tg≦100°C, especially Tg≦80°C, especially Tg≦70°C. The light-emitting component of any one of the preceding claims, wherein the solid polymer is constructed as a sheet-like polymer, and/or wherein the solid polymer is sandwiched between two barrier layers. A light-emitting device, especially a liquid crystal display (LCD), comprising the light-emitting assembly according to any one of claims 1 to 11. The light-emitting device of claim 12, wherein the light-emitting component comprises: - an array of more than one light source (10) with individually adjacent first layers (1), - a second layer (2) disposed away from the array, and - a diffuser plate (3) arranged between the first layer (1) and the second layer (2), In particular, wherein the array covers substantially the entire liquid crystal display area. A lighting device as claimed in claim 12 or 13, wherein one or more of the light sources (10) of the array are each adapted to switch on and off with a frequency f of f≧150 Hz, especially f≧300 Hz, More particularly f≧600 Hz. A free-standing film comprising a light-emitting crystal (20) embedded in a polymer, wherein the light-emitting crystal (20) is of a perovskite structure and emits green light (cc) and /or red light (bb), and wherein the free-standing film has a haze h ₂ of 20≦h ₂ ≦70%, especially h ₂ < 80%, especially h ₂ < 70%, more especially h ₂ < 60 %. The free-standing film of claim 15, wherein the polymer comprises scattering particles. The free-standing film of claim 15 or 16, wherein the luminescent crystal (20) is embedded in a cross-linked solid polymer. The free-standing film of any one of claims 15 to 17, wherein the light-emitting crystal (20) is a compound selected from the group consisting of compounds of formula (II): [M ¹ A ¹ ] _a M ² _b X _c (II), wherein: A ¹ represents one or more organic cations, preferably ammonium formate, M ¹ represents one or more alkaline earth metals, M ² represents one or more metals other than M ¹ , especially Pb, X represents selected from halides, pseudohalides and one or more anions of the group consisting of sulfides, especially Br, a for 1-4, b for 1-2, c for 3-9, and in which M ¹ or A ¹ or M ¹ and A ¹ are present . The free-standing membrane of claim 18, • wherein M ² represents Pb, and • wherein the concentration of Pb is 5-200 mg/m ² , especially 10-100 mg/m ² , more especially 20-80 mg/m ² . A free-standing film as claimed in any one of claims 16 to 19, wherein the solid polymer comprises acrylates, in particular comprises or consists of repeating units selected from the group of cycloaliphatic acrylates, in particular, and/ or wherein the acrylate comprises repeating units selected from monofunctional acrylate monomers and multifunctional acrylate monomers. The free-standing membrane of any one of claims 16 to 20, wherein the solid polymer is characterized by a molar ratio of the sum of (oxygen+nitrogen) to carbon of < 0.9, preferably < 0.4, preferably < 0.3 , the best is < 0.25. The free-standing film of any one of claims 16 to 21, wherein the solid polymer has a glass transition temperature Tg of Tg≦120°C, especially Tg≦100°C, especially Tg≦80°C, especially Tg≦70°C . The free-standing film of any one of claims 16 to 22, wherein the solid polymer is constructed as a sheet polymer, and/or wherein the solid polymer is sandwiched between two barrier layers. A light emitting device, in particular a liquid crystal display (LCD), comprising a free-standing film as claimed in any one of claims 15 to 23.

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