LUMINESCENT COMPONENT

Abstract

Described are luminescent components with excellent performance and stability. The luminescent components comprise a first element 1 including first luminescent crystals 11 from the class of perovskite crystals, embedded a first polymer P1 and a second element 2 comprising a second solid polymer composition, said second polymer composition optionally comprising second luminescent crystals 12 embedded in a second polymer P2. Polymers P1 and P2 differ and are further specified in the claims. Also described are methods for manufacturing such components and devices comprising such components.

Claims

1. A luminescent component, comprising a first element and a second element, wherein: said first element comprises a first solid polymer composition, said first polymer composition comprising first luminescent crystals embedded in a first polymer (P1), wherein said first luminescent crystals are of the perovskite crystal structure and emit light of a first wavelength in response to excitation by light with a wavelength shorter than the first wavelength, said first polymer (P1) is selected from the group consisting of crosslinked polymers and polymers with Tg<95° C.; said second element comprises a second solid polymer composition, said second polymer composition optionally comprising second luminescent crystals embedded in a second polymer (P2), wherein said optional second luminescent crystals are different from said first luminescent crystals and emit light of a second wavelength in response to excitation by light with a wavelength shorter than the second wavelength, said second polymer (P2) is selected from the group of crosslinked polymers; and wherein said second element at least partially covers and thereby seals said first element; and said Tg is measured according to DIN EN ISO 11357-2: 2014-07 during the second heating cycle and applying a heating rate of 20K/min, starting at −90° C. up to 250° C.

2. The luminescent component according to claim 1, wherein P1 and/or P2 complies with one or more of the following parameters: P1 has a molar ratio of the sum of (oxygen+nitrogen+sulphur+phosphorous+fluorine+chlorine+bromine+iodine) to carbon<0.9; P2 has a molar ratio of the sum of (oxygen+nitrogen+sulphur+phosphorous+fluorine+chlorine+bromine+iodine) to carbon<0.9; Water vapour transmission rate (WVTR) of P1<1 (g*mm)/(m.sup.2*day); WVTR of P2<1 (g*mm)/(m.sup.2*day); Oxygen transmission rate (OTR) of P1>1 (cm3*mm)/(m2*day*atm); OTR of P2<50 (cm.sup.3*mm)/(m.sup.2*day*atm); Tg of P2>115° C.; light transmittance of P1 and P2 >70%; wherein the first polymer (P1) is not dissolvable in the second polymer (P2), and vice versa.

3. The luminescent component according to claim 1, wherein the first polymer (P1) is selected from the group of acrylate polymers and wherein the second polymer (P2) is selected from the group of acrylate polymers.

4. The luminescent component according to claim 1, wherein the first polymer (P1) comprises repeating units of formulae (III) and (V) and/or the second polymer (P2) comprises repeating units of formula (VI) and optionally of formula (III): ##STR00009## wherein: R.sup.9 represents H or CH.sub.3, R.sup.10 represents a cyclic, linear or branched C.sub.1-25 alkyl, or a C.sub.6-26 aryl group, each optionally substituted with one or more cyclic, linear or branched C.sub.1-20 alkyl, phenyl or phenoxy, n represents 0 or 1, and X represents a spacer from the group of alkoxylates comprising 1-8 carbon atoms and 1-4 oxygen atoms; ##STR00010## wherein: R.sup.21 independently from each other represent H or CH.sub.3; R.sup.23 represents a cyclic, linear or branched C.sub.1-25 alkyl, or a C.sub.6-26 aryl group, each optionally substituted with one or more cyclic, linear or branched C.sub.1-20 alkyl, phenyl or phenoxy; X.sup.22 independently from each other represent a spacer selected from the group of alkoxylates, whereby both substituents X.sup.22 together comprise 8-40 carbon atoms and 2-20 oxygen atoms; ##STR00011## wherein: R.sup.31 independently from each other represent H or CH.sub.3; R.sup.33 represents a cyclic C.sub.5-25 alkyl, or a C.sub.6-26 aryl group, each optionally substituted with one or more cyclic, linear or branched C.sub.1-20 alkyl, phenyl or phenoxy; X.sup.32 are independent from each other and are either not present or represent a spacer from the group of alkoxylates, whereby both substituents X.sup.32 together comprise 1-8 carbon atoms and 1-8 oxygen atoms.

5. The luminescent component according to claim 1, wherein the first luminescent crystals are selected from compounds of formula (I):
[M.sup.1A.sup.1].sub.aM.sup.2.sub.bX.sub.c   (I), wherein: A.sup.1 represents one or more organic cations, M.sup.1 represents one or more alkaline metals, M.sup.2 represents one or more metals other than M.sup.1, X represents one or more anions selected from the group consisting of halides, pseudohalides and sulfide, a represents 1-4, b represents 1-2, c represents 3-9, and wherein either M.sup.1, or A.sup.1, or M.sup.1 and A.sup.1 being present; and/or wherein said first luminescent crystals are of size between 3-100 nm.

6. The luminescent component according to claim 1, wherein the second luminescent crystals are selected from one or more of core-shell QDs and micron-sized phosphors.

7. The luminescent component according to claim 1, further comprising third luminescent crystals selected from one or more of perovskite crystals, core-shell QDs and micron-sized phosphors.

8. The luminescent component according to claim 1 in the form of a film, particularly a QD backlight film or a down conversion film, said film comprising the following layered structure: layer of first element—layer of second element; or layer of second element—layer of first element—layer of second element; or protecting layer—layer of second element—layer of first element—layer of second element—protecting layer.

9. The luminescent component according to claim 8 wherein said protecting layer is selected from glass; a polymer with humidity barrier properties; a polymer with oxygen barrier properties; and a polymer coated with an oxide layer.

10. The luminescent component according to claim 1, wherein one or more first elements are arranged on a substrate and covered by a layer comprising said second element; or a layer comprising said first element is arranged on a substrate and coated by a layer comprising said second element.

11. The luminescent component according to claim 1, wherein a plurality of first elements are dispersed in a matrix and fully covered by the second element .

12. A light emitting device, comprising a luminescent component according to claim 1, a light source for emitting blue light, wherein the light source is arranged for exciting the luminescent component.

13. The light emitting device according to claim 12 selected from the group consisting of displays, particularly liquid crystal displays, OLED displays, QLED displays, micro LED displays; and lighting devices, particularly LEDs, OLEDs, QLEDs.

14. A backlight in a liquid crystal display comprising a luminescent component of claim 1, for emitting white light in response to the luminescent component being radiated by blue light.

15. A method for manufacturing a luminescent component according to claim 1, comprising the steps of: —Method A— providing a substrate which is optionally coated with one or more layers; applying to said substrate a first liquid polymer composition comprising monomers or oligomers of the first polymer P1, first luminescent crystals, optionally solvent, optionally further materials, optionally third luminescent crystals; optionally heating said liquid first polymer composition at elevated temperature to remove volatile solvents; curing said first liquid polymer composition to obtain the first element; applying to the thus obtained hardened surface of said first element a second liquid polymer composition comprising monomers or oligomers of the second polymer P2, optionally second luminescent crystals, optionally solvent, optionally further materials; optionally heating said liquid second polymer composition at elevated temperature to remove volatile solvents; curing said liquid second polymer composition to obtain the second element, which covers and thereby seals said first element; optionally applying further coating or finishing steps; OR —Method B 13 providing a substrate which is optionally coated with one or more layers; applying to said substrate a second liquid polymer composition as defined above; optionally heating said liquid second polymer composition at elevated temperature to remove volatile solvents; curing said second polymer composition to obtain the second element; applying to the thus obtained hardened surface of said second element a first liquid polymer composition as defined above; optionally heating said liquid first polymer composition at elevated temperature to remove volatile solvents; curing said liquid first polymer composition to obtain the first element, which is covered and thereby sealed by said second element on its lower surface; applying further coating or finishing steps; OR —Method C— providing two substrates each coated with a layer of the second element laminating a layer of first elements with these coated substrates; OR —Method D— providing a first liquid polymer composition comprising monomers or oligomers of the first polymer P1, first luminescent crystals, optionally solvent, optionally further materials, optionally third luminescent crystals; one of a) extracting multiple first elements from the first liquid polymer composition by one of spray-drying, or precipitation, or b) hardening the first liquid polymer composition into the first solid polymer composition, and crushing the first solid polymer composition resulting in multiple first elements, mixing the first elements into a second liquid polymer composition as defined above, and providing a substrate which is optionally coated with one or more layers; applying to said substrate said second liquid polymer composition containing the first elements; optionally heating said liquid second polymer composition at elevated temperature to remove volatile solvents; curing said liquid second polymer composition to obtain the second element, which covers and thereby seals said first elements; and optionally applying further coating or finishing steps.

16. The luminescent component according to claim 4 in the form of a film, particularly a QD backlight film or a down conversion film, said film comprising the following layered structure: layer of first element—layer of second element; or layer of second element—layer of first element—layer of second element; or protecting layer—layer of second element—layer of first element—layer of second element—protecting layer.

Description

DESCRIPTION OF THE DRAWINGS

[0236] Embodiments, examples, experiments representing or leading to embodiments, aspects and advantages of the invention will be better understood from the following detailed description thereof. Such description makes reference to the annexed drawings, wherein:

[0237] FIG. 1 illustrates a schematic view of a luminescent component (4) according to embodiments of the present invention. A: First luminescent crystals (11) only, B: First (11) and second (12) luminescent crystals, C: First (11) and third (13) luminescent crystals.

[0238] FIG. 2 illustrates a schematic view of a luminescent component (4) in the form of a film according to embodiments of the present invention, such components are particularly suitable for display devices. A: no additional barrier; B: transparent single layer barrier (with no substructure); C: transparent multilayer barrier (with substructure), D: sheet-like component wherein the first element is fully covered with second element with an additional barrier on both sides.

[0239] FIG. 3 illustrates a schematic view of a luminescent component in the form of discrete elements according to embodiments of the present invention. A: component with a flat substrate (3), particularly suitable for lighting devices; B: component with a structured substrate (3), particularly suited for pixels.

[0240] FIG. 4 illustrates a light emitting device of the matrix type according to another embodiment of the present invention.

[0241] FIG. 5 illustrates the relative photoluminescence quantum yield (PLQY) change after degradation for 150h of selected luminescent components including a component according to the present invention (example 4).

[0242] FIG. 6 illustrates the relative photoluminescence quantum yield (PLQY) change after degradation for 150h of selected luminescent components including a component according to the present invention (example 6).

[0243] FIG. 7 illustrates the Δy (change of colour coordinate y of the CIE 1931 colour space chromaticity diagram) after degradation for 500h of selected luminescent components including a component according to the present invention (example 10).

TABLE-US-00001 Reference list: (P1) First Polymer; (P2) Second Polymer  (1) First Element;  (2) Second Element (11) First luminescent crystals (12) Second luminescent crystals (13) Third Luminescent crystals (3) (31), (32) Substrate  (4) Luminescent Component (5), (51), (52) Protecting layer

EXAMPLES

[0244] To further illustrate the invention, the following examples are provided. These examples are provided with no intent to limit the scope of the invention. If not stated otherwise, all of the chemicals were purchased from Aldrich.

[0245] Example 1-4: Synthesis of luminescent components according to the invention (fully covered P1 in P2, c.f FIG. 2D. Ex. 1, 2 and 3 for comparison, ex. 4 according to the invention.)

[0246] Ink formation: Formamidinium lead tribromide (FAPbBr.sub.3) was synthesized by milling PbBr.sub.2 and FABr. Namely, 16 mmol PbBr.sub.2 (5.87 g, 98% ABCR, Karlsruhe (DE)) and 16 mmol FABr (2.00 g, Greatcell Solar Materials, Queanbeyan, (AU)) were milled with Yttrium stabilized zirconia beads (5 mm diameter) for 6 h to obtain pure cubic FAPbBr.sub.3, confirmed by XRD. The orange FAPbBr.sub.3 powder was added to Oleylamine (80-90, Acros Organics, Geel (BE)) (weight ratio FAPbBr3:Oleylamine=100:15) and toluene (>99.5%, puriss, Sigma Aldrich). The final concentration of FAPbBr.sub.3 was 1wt %. The mixture was then dispersed by ball milling using yttrium stabilized zirconia beads with a diameter size of 200 μm at ambient conditions (if not otherwise defined, the atmospheric conditions for all experiments are: 35° C., 1 atm, in air) for a period of 1 h yielding an ink with green luminescence.

[0247] Film formation: For the first film (P1-glass) 0.1 g of the green ink was mixed with an UV curable monomer/crosslinker mixture (0.7 g FA-513AS, Hitachi Chemical, Japan/0.3 g Miramer M240, Miwon, Korea) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TCI Europe, Netherlands) in a speed mixer and the toluene was evaporated by vacuum (<0.01 mbar) at room temperature. The resulting mixture was cured between two glass slides (18x18 mm) with a thickness of approximately 100μm for 60 s in UV (UVAcube100 equipped with a mercury lamp and quartz filter, Hoenle, Germany). A second film (P2-glass) was prepared as above with 0.1 g green ink and UV curable monomer/crosslinker mixture (0.7 g FA-DCPA, Hitachi Chemical, Japan/0.3 g FA-320M, Hitachi Chemical, Japan) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide. A third film (P1/P1-glass) was prepared by preparing a film as described for the first film above but then delaminating this film from the two glass slides. This free-standing film was then coated between two glass slides in the same matrix of (0.7 g FA-513AS, Hitachi Chemical, Japan/0.3 g Miramer M240, Miwon, Korea) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide and cured as described above. A fourth film (P1/P2-glass) was prepared by preparing a film as described for the first film above but then delaminating this film from the two glass slides. This free-standing film was then coated between two glass slides in a different matrix of (0.7 g FA-DCPA, Hitachi Chemical, Japan/0.3 g FA-320M, Hitachi Chemical, Japan) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide and cured as described above. The third and fourth film was coated such that the matrix fully covered the free-standing film.

[0248] Analysis: Table 1 shows the optical properties of the film as initially obtained and after degradation for 150 hours subjecting the samples to a high temperature test (90° C./dry) (i.e. ambient humidity, approximately 2% relative humidity), a high temperature/high humidity test (60° C./90%rH) and a high flux test (blue LED light, 460nm blue emission, 280mW/cm2, 50° C., LEDcube100, Hoenle, Germany). The light intensity was measured with a UV meter equipped with a VIS area sensor (Hoenle, Germany). The resulting optical properties of the film were measured with a spectrofluorimeter equipped with an integrating sphere (Quantaurus Absolute PL quantum yield measuring system C1134711, Hamamatsu).

TABLE-US-00002 TABLE 1 Ex.#: PLQY PP FWHM rel. (description) test condition (%) (nm) (nm) ΔPLQY* comparison 1: initial 90 526 23 N/A** P1-glass 150 h 51 526 22 −43% (FA-513AS/ (90° C./dry) Miramer M240 + 150 h 80 526 23 −11% green LCs) (60° C./90% rH) 150 h 84 524 24  −7% high flux 2: initial 90 525 23 N/A** P2-glass 150 h 72 525 23 −20% (FA-DCPA/FA- (90° C./dry) 320M + green LCs) 150 h 87 527 23  −3% (60° C./90% rH) 150 h 22 522 25 −76% high flux 3: initial 87 525 23 N/A** P1/P1-glass 150 h 48 526 22 −45% (FA-513AS/ (90° C./dry) Miramer M240 + 150 h 79 525 22  −9% green LCs) (60° C./90% rH) encapsulated in 150 h 88 525 24  +1% (FA-DCPA/FA- high flux 320M) inventive 4: initial 86 525 23 N/A** P1/P2-glass 150 h 75 526 22 −13% (FA-513AS/ (90° C./dry) Miramer M240 + 150 h 87 525 23  +1% green LCs) (60° C./90% rH) encapsulated in 150 h 80 524 24  −7% (FA-DCPA/FA- high flux 320M) *rel. ΔPLQY: relative change of PLQY compared to initial value **N/A: not applicable

[0249] Conclusion: These results show that a luminescent component as described in this invention (Ex.4) exhibits excellent initial properties and maintain high optical performance after accelerated degradation in all test conditions (FIG. 5). Ex.1 and Ex.3 show inferior performance after degradation in 90° C./dry and 60° C./90%rH, Ex.2 inferior performance after degradation in (high flux) rendering these components unsuitable for application in TVs or the like.

[0250] Examples 5-6: Synthesis of luminescent components according to the invention (fully covered P1 pieces in P2, c.f fig.4; Ex. 5 for comparison, ex. 6 according to the invention.)

[0251] Ink formation: The ink was prepared as described in examples 1-4.

[0252] Film formation: The first film (P1-glass) was prepared like the first film of example 1. A second film (P1/P2-glass) was prepared by preparing a film as described for the first film above. Then this film was delaminated from the two glass slides and cut in small pieces approximately 0.5mm ×0.5mm ×0.1 mm in size. These P1 pieces were then mix into a matrix of (0.7 g FA-DCPA, Hitachi Chemical, Japan/0.3 g FA-320M, Hitachi Chemical, Japan) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide with a weight ratio of 1:3 (P1 pieces/matrix) and subsequently coated and cured as described above. The second film was coated such that the matrix fully covered the P1 pieces.

[0253] Analysis: Table 2 shows the optical properties of the film as initially obtained and after degradation for 150 hours subjecting the samples to a high temperature test (90° C./dry) (i.e. ambient humidity, approximately 2% relative humidity), a high temperature/high humidity test (60° C./90%rH) and a high flux test (blue LED light, 460nm blue emission, 350mW/cm2, 50° C., LEDcube100, Hoenle, Germany). The light intensity was measured with a UV meter equipped with a VIS area sensor (Hoenle, Germany). The resulting optical properties of the film were measured with a spectrofluorimeter equipped with an integrating sphere (Quantaurus Absolute PL quantum yield measuring system C1134711, Hamamatsu).

TABLE-US-00003 TABLE 2 Ex.#: PLQY PP FWHM rel. (description) test condition (%) (nm) (nm) ΔPLQY* comparison 5: initial 95 523 22 N/A** P1-glass 150 h 74 523 22 −22% (FA-513AS/ (90° C./dry) Miramer M240 + 150 h 92 523 22  −3% green LCs) (60° C./90% rH) 150 h 84 522 24 −12% high flux inventive 6: initial 88 522 22 N/A** P1/P2-glass 150 h 89 522 22  +1% (FA-513AS/ (90° C./dry) Miramer M240 + 150 h 91 522 22  +3% green LCs) (60° C./90% rH) encapsulated in 150 h 73 520 24 −17% (FA-DCPA/FA- high flux 320M) *rel. ΔPLQY: relative change of PLQY compared to initial value **N/A: not applicable

[0254] Conclusion: These results show that a luminescent component as described in this invention (Ex.6) exhibits excellent initial properties and maintain high optical performance after accelerated degradation in all test conditions (FIG. 6). Ex.5 shows significantly inferior performance after degradation in 90° C./dry rendering this component unsuitable for application in TVs or the like.

[0255] Examples 7-10: Synthesis of luminescent components according to the invention (partially covered P1 in P2, c.f. FIG. 2A, 2B, 2C). Ex. 7, 8 and 9 for comparison, ex. 10 according to the invention.

[0256] Ink formation: The ink was prepared as described in examples 1-4.

[0257] Film formation: For the first film (P1-barrier) 0.3 g of the green ink from example 5-6 was mixed with an UV curable monomer/crosslinker mixture (2.1 g FA-513AS, Hitachi Chemical, Japan/0.9 g Miramer M240, Miwon, Korea) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TCI Europe, Netherlands) in a speed mixer and the toluene was subsequently evaporated by vacuum (<0.01 mbar) at room temperature. The resulting mixture was coated with a thickness of 100 μm between two barrier films (TBF1004, i-components, Korea). This barrier film exhibited a WVTR of 0.022 g/(m2*day) (Mocon test) based on the manufacturer's inspection report.

[0258] Curing was done in a UV belt (BE20/120W/II, Beltron, Germany) equipped with two mercury lamp and quartz filter. Curing conditions were 31% lamp intensity for both lamps and 4.1 m/min line speed, resulting in a UV energy of about 850 mJ/cm2 measured with a UV integrator type D (Beltron, Germany).

[0259] A second film (P2-barrier) was prepared as above with 0.3 g green ink and UV curable monomer/crosslinker mixture (2.1 g FA-DCPA, Hitachi Chemical, Japan/0.9 g FA-320M, Hitachi Chemical, Japan) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide. Coating thickness was 100 μm and the curing conditions were 75% lamp intensity for both lamps and 5 m/min line speed, resulting in a UV energy of about 1700 mJ/cm2.

[0260] A third film (P1/P1-barrier) was prepared by first coating a 30 μm overcoat on two separate barrier films (TBF1004, i-components, Korea) with an UV curable monomer/crosslinker mixture (2.1 g FA-513AS, Hitachi Chemical, Japan/0.9 g Miramer M240, Miwon, Korea) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TCI Europe, Netherlands). The overcoat was covered with a cellulose acetate viewfoil and subsequently curing was done with the UV belt at 31% lamp intensity for both lamps and 8.2 m/min line speed, resulting in a UV energy of about 425 mJ/cm2. Then 0.3 g green ink and UV curable monomer/crosslinker mixture (2.1 g FA-513AS, Hitachi Chemical, Japan/0.9 g Miramer M240, Miwon, Korea) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide were mixed and toluene evaporated as described above. This mixture was coated (100 μm thickness) between the two overcoated barrier films and cured with 31% lamp intensity for both lamps and 1.0 m/min line speed, resulting in a UV energy of about 3400 mJ/cm2.

[0261] A fourth film (P2/P1-barrier) was prepared by first coating a 30 pm overcoat on two barrier films (TBF1004, i-components, Korea) with an UV curable monomer/crosslinker mixture (2.1 g FA-DCPA, Hitachi Chemical, Japan/0.9 g FA-320M, Hitachi Chemical, Japan) containing 1wt % photoinitiator

[0262] Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TCI Europe, Netherlands). The overcoat was covered with a cellulose acetate viewfoil and subsequently curing was done with the UV belt at 31% lamp intensity for both lamps and 8.2 m/min line speed, resulting in a UV energy of about 425 mJ/cm2. Then 0.3 g green ink and UV curable monomer/crosslinker mixture (2.1 g FA-513AS, Hitachi Chemical, Japan/0.9 g Miramer M240, Miwon, Korea) containing 1 wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide were mixed and toluene evaporated as described above. This mixture as coated (100 μm thickness) between the two overcoated barrier films and cured with 31% lamp intensity for both lamps and 1.0 m/min line speed, resulting in a UV energy of about 3400 mJ/cm2. Samples of size 3cmx3cm were cut from all four films and tested for degradation. By cutting sample from the third (P1/P1-barrier) and fourth film (P2/P1-barrier) the P1 layer containing LCs is subjected to the environment at the cutting surface.

[0263] Analysis: Table 3 shows the optical properties of the film as initially obtained and after degradation for 500 hours subjecting the samples to a high temperature test (90° C./dry) (i.e. ambient humidity, approximately 2% relative humidity), a high temperature/high humidity test (60° C./95%rH) and a high flux test (blue LED light, 460 nm blue emission, 280mW/cm2, 50° C., LEDcube100, Hoenle, Germany). The light intensity was measured with a UV meter equipped with a VIS area sensor (Hoenle, Germany). The performance of the films was obtained by placing the samples on a magenta backlight unit and measuring the optical properties with a spectroradiometer (CS-2000, Konica Minolta).

TABLE-US-00004 TABLE 3 Ex.#: x-value* y-value* PP FWHM (composition) test condition (−) (−) (nm) (nm) Δy** comparison 7: P1-barrier initial 0.248 0.190 526 22 N/A*** (FA-513AS/ Miramer 500 h 0.249 0.122 541 33 −0.068 M240 + (90° C./dry) green LCs) 500h 0.240 0.125 524 22 −0.065 (60° C./ 90% rH) 500 h 0.245 0.160 524 23 −0.030 high flux 8: P2-barrier initial 0.253 0.216 526 23 N/A** (FA-DCPA/ FA-320M + 500 h 0.253 0.209 526 22 −0.007 green LCs) (90° C./dry) 500h 0.255 0.214 527 22 −0.002 (60° C./ 90% rH) 500 h 0.261 0.096 523 44 −0.120 high flux 9: P1/P1- initial 0.251 0.200 525 23 N/A** barrier (FA-513AS/ 500 h 0.256 0.132 526 27 −0.068 Miramer (90° C./dry) M240 + 500 h 0.250 0.183 525 22 −0.017 green LCs) (60° C./ covered by 90% rH) (FA-513AS/ 500 h 0.247 0.183 524 24 −0.017 Miramer high flux M240) inventive 10: P2/P1- initial 0.252 0.208 526 23 N/A** barrier (FA-513AS/ 500 h 0.252 0.197 526 22 −0.011 Miramer (90° C./dry) M240 + 500h 0.252 0.198 526 23 −0.010 green LCs) (60° C./ covered by 90% rH) (FA-DCPA/ 500 h 0.249 0.179 523 24 −0.028 FA-320M) high flux *x-value, y-value: colour values of the CIE 1931 colour space chromaticity diagram.; **Δy: absolute change of initial y-value to y-value after 500 h degradation; ***N/A: not applicable

[0264] Analysis of T.sub.g: The glass transition temperature of the elements of the luminescent component as described in this invention was determined by DSC according to DIN EN ISO 11357-2:2014-07 with a starting temperature of—90° C. and an end temperature of 250° C. and a heating rate of 20 K/min in nitrogen atmosphere (20 ml/min). The purging gas was nitrogen (5.0) at 20 ml/min. The DSC system DSC 204 F1 Phoenix (Netzsch) was used. The T.sub.g was determined on the second heating cycle (the first heating from −90° C. to 250° C. showed overlaying effects besides the glass transition). A first sample (P1+LCs) was prepared similar to the above films from example 7 by mixing 0.3 g of the green ink from example 1-4 with an UV curable monomer/crosslinker mixture (2.1 g FA-513AS, Hitachi Chemical, Japan/0.9 g Miramer M240, Miwon, Korea) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TCI Europe, Netherlands) in a speed mixer and the toluene was subsequently evaporated by vacuum (<0.01 mbar) at room temperature. The resulting mixture was coated with a thickness of 30-40 μm between two 100 μm cellulose acetate viewfoils. Curing was done in a UV belt (BE20/120W/II, Beltron, Germany) equipped with two mercury lamp and quartz filter. Curing conditions were 31% lamp intensity for both lamps and 1.0 m/min line speed, resulting in a UV energy of about 3400 mJ/cm2 measured with a UV integrator type D (Beltron, Germany). A second sample (P2) was prepared similar to the above films from example 10 by mixing an UV curable monomer/crosslinker mixture (2.1 g FA-DCPA, Hitachi Chemical, Japan/0.9 g FA-320M, Hitachi Chemical, Japan) containing 1wt % photoinitiator Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TCI Europe, Netherlands) in a speed mixer. The resulting mixture was coated with a thickness of 30-40 pm between two 100 μm cellulose acetate viewfoils. Curing was done in a UV belt (BE20/120W/II, Beltron, Germany) equipped with two mercury lamp and quartz filter. First curing conditions were 31% lamp intensity for both lamps and 1.0 m/min line speed (UV energy about 3400 mJ/cm2). For both samples (P1+LCs) and (P2) the viewfoils were removed and the remaining films subjected to T.sub.g analysis in duplicate. The T.sub.g for (P1+LCs) was 77° C. and 74° C. whereas for (P2) T.sub.g was 143° C. and 142° C.

[0265] Conclusion: These results show that a luminescent component as described in this invention (Ex. 10) exhibit excellent initial properties and maintain high optical performance after accelerated degradation in all test conditions (FIG. 7). Example 7 shows inferior performance after degradation in (90/dry) and (60° C./90%rH) and example 8 performs significantly worse after degradation in (high flux), while example 9 shows a pronounced degradation in (90° C./dry) rendering these film systems unsuitable for application in TVs or the like.

[0266] Example 11-12: Synthesis of luminescent components and pre-concentrates from different inks according to the invention.

[0267] Ink formation: Formamidinium lead tribromide (FAPbBr.sub.3) was synthesized by milling PbBr.sub.2 and FABr. Namely, 16 mmol PbBr.sub.2 (5.87 g, 98% ABCR, Karlsruhe (DE)) and 16 mmol FABr (2.00 g, Greatcell Solar Materials, Queanbeyan, (AU)) were milled with Yttrium stabilized zirconia beads (5 mm diameter) for 6 h to obtain pure cubic FAPbBr.sub.3, confirmed by XRD. The orange FAPbBr.sub.3 powder was added to Oleylamine (80-90%, Acros Organics, Geel (BE)) and .sub.3-(N,N-Dimethyloctadecylammonio)propanesulfonate (>99%, Sigma Aldrich) (weight ratio FAPbBr.sub.3:OIeylamine:3-(N,N-Dimethyloctadecylammonio) propanesulfonate=100:30:10) and toluene (>99.5%, puriss, Sigma Aldrich).

[0268] The final concentration of FAPbBr.sub.3 was 3wt %. The mixture was then dispersed by ball milling using yttrium stabilized zirconia beads with a diameter size of 200 μm at ambient conditions (if not otherwise defined, the atmospheric conditions for all experiments are: 35° C., 1 atm, in air) for a period of 1 h yielding an ink with green luminescence. The ink showed an absorbance at 450nm of 0.789 in a 2mm optical path cuvette when diluted by a factor of 10.6. Hence the scaled absorbance was the absorbance multiplied with the dilution factor=0.78910.6 =8.4. The solid load of the ink was determined by subjecting the ink to 350° C. in air for 20 hours. The residual was confirmed to be PbBr2 by XRD and from the PbBr2 residual weight=8.1 mg/(g ink) the solid load of

[0269] FAPbBr3 in percentage is calculated to be 1.1% (=0.011). The scaled absorbance at 450nm per solid load can then be calculated to be 764 (=8.4/0.011). Optical properties were measured with a spectrofluorimeter equipped with an integrating sphere (Quantaurus Absolute PL quantum yield measuring system C1134711, Hamamatsu) after dilution of 1:1200 ink:dry toluene. The PLQY was 91%, with an emission peak wavelength (or peak position, PP) of 505nm and a FWHM of 30nm. Above ink was treated with an additional ligand octylamine (99%, Sigma Aldrich) in the weight ratio (ink:ligand=100:0.4) obtaining a modified ink. The resulting modified ink was centrifuged and analyzed again as described above having a PLQY of 95%, PP of 503nm, FWHM 31nm, a scaled absorbance at 450nm of 3.4 and solid loading of 0.6% (=0.006), resulting in a scaled absorbance at 450nm per solid loading of 567 (=3.4/0.006). The decreased scaled absorbance at 450nm per solid loading indicates that a portion of the initial luminescent FAPbBr.sub.3 crystals are now dissolved or complexed by the addition of the ligand octyl amine.

[0270] Pre-concentrate formation: In above centrifuged ink and centrifuged modified ink, the solvent can be exchanged from toluene to an acrylate monomer resulting in a respective pre-concentrate. This was obtained by adding 1.4 g of ink and 2.2 g of modified ink in 0.7 g and 1.1 of isobornyl methacrylate (technical grade, Sigma Aldrich), respectively. Toluene was evaporated in a rotary evaporator at 80° C. and a final pressure of 20mbar for 30min, resulting in a toluene concentration of below 5wt % determined gravimetrically. The resulting pre-concentrate 1 for the ink and the pre-concentrate 2 for the modified ink were centrifuged and analyzed again as described above having a PLQY of 91%, PP of 506 nm, FWHM 30 nm and a scaled absorbance at 450nm of 16.5 for pre-concentrate 1 and a PLQY of 96%, PP of 502 nm, FWHM 31 nm and a scaled absorbance at 450 nm of 6.6 for pre-concentrate 2. The preservation of the scaled absorbance at 450 nm and no observation of precipitate suggests the lossless transfer from both inks to the corresponding pre-concentrates and hence the preservation of the corresponding scaled absorbance (at 450 nm) per solid loading.

[0271] Film formation: Two films (P1-glass) were prepared like the first film described in example 1 from the ink resulting in film 1 and the modified ink resulting in film 2.

[0272] Analysis: Table 4 shows the optical properties of the ink, the modified ink, the pre-concentrate 1, the pre-concentrate 2, the film 1 and the film 2.

TABLE-US-00005 TABLE 4 Ex.#: (description) PLQY (%) PP (nm) FWHM (nm) 11: ink 91 505 30 pre-concentrate 1 91 506 30 film 1 93 520 24 12: modified ink 95 503 31 pre-concentrate 2 96 502 31 film 2 94 520 24

[0273] Conclusion: These results show that a pre-concentrate in acrylate can be obtained from an ink according to the invention. The luminescent component prepared from described inks exhibit excellent initial properties rendering these film systems suitable for application in TVs or the like.