Light-blocking coatings comprising metal halide compounds, and associated systems, devices and methods

Abstract

A UV-blocking coating is provided. The UV-blocking coating includes a metal halide compound and alloys thereof. The metal halide compound includes CsPbX3, CsPb2X5, Cs4PbX6, Cs2AgBiX6, or Cs2NaInX6, wherein X is Cl, Br, I, or a combination thereof. The UV-blocking coating can serve as a protective or encapsulant layer in devices such as solar panels or protective eyewear.

Description

LIGHT-BLOCKING COATINGS COMPRISING METAL HALIDECOMPOUNDS, AND ASSOCIATED SYSTEMS, DEVICES AND METHODSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U. S. Provisional Patent ApplicationNo. 63 / 633,618, filed April 12, 2024, the contents of which as are hereby incorporated herein by reference in their entirety for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates to high energy light-blocking coatings comprising metal halide compounds, and associated systems, devices, and methods. Particular embodiments relate to UV-blocking coatings comprising metal halide compounds, including CsPbXs, CsPb2Xs, CsrPbXe, Cs2AgBiXe, and Cs2NaInXe, in which X is Cl, Br, I, and / or combinations thereof, for applications such as window coatings, protective eyewear, and solar module protection.INTRODUCTION

[0003] Prolonged exposure to high energy light poses risks to both organic and inorganic materials. In the case of organic materials, such as human skin or polymers, ultraviolet and higher energy (UV+) light can lead to degradation and harmful photochemical reactions. In the case of inorganic materials, like the active layers in solar cells, UV+ light can accelerate wear and reduce efficiency. There exists a need for efficient, durable, and non-toxic materials that can absorb or block UV+ light to protect materials and structures from these effects.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 is a schematic illustration of a system for creating a coating comprising a UV+ blocking compound, in accordance with embodiments of the present technology.

[0005] Figures 2A and 2B show optical absorption spectra for representative UV+ blocking coatings on various substrates such as glass and fluoropolymers.

[0006] Figures 3 A-3D show optical images of representative UV+ blocking coatings on various substrates such as glass and fluoropolymers.DETAILED DESCRIPTION

[0007] Various embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments are shown. Indeed, various embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. In the following description, various components may be identified as having specific values or parameters; however, these items are provided as exemplary embodiments. Indeed, the exemplary embodiments do not limit the various aspects and concepts of the embodiments as many comparable parameters, sizes, ranges, and / or values may be implemented. The terms “first,” “second,” and the like, as well as “exemplary” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Further, the terms “a,” “an,” and “the” do not denote a limitation of quantity, but rather denote the presence of “at least one” of the referenced item.

[0008] Each embodiment disclosed herein is contemplated as being applicable to each of the other disclosed embodiments. All combinations and sub-combinations of the various elements described herein are within the scope of the embodiments.

[0009] It is understood that where a parameter range is provided, all integers and ranges within that range, and tenths and hundredths thereof, are also provided by the embodiments. For example, “5-10%” includes 5%, 6%, 7%, 8%, 9%, and 10%; 5.0%, 5.1%, 5.2%....9.8%, 9.9%, and 10.0%; and 5.00%, 5.01%, 5.02%....9.98%, 9.99%, and 10.00%, as well as, for example, 6-9%, 5. l%-9.9%, and 5.01%-9.99%.

[0010] As used herein, “about” in the context of a numerical value or range means within ±10% of the numerical value or range recited or claimed.I. Overview

[0011] The present disclosure provides for UV± blocking coatings comprising or consisting of a metal halide compound. In some embodiments, the UV+ blocking coating is a cesium halide compound or cesium lead halide compound, such as CsPbXs, CsPb2Xs, Cs4PbXe, Cs2AgBiXe, and Cs2NaInXe (X is Cl, Br, and / or I), and alloys thereof. These compounds are referred to herein as “target compounds.” These target compounds can effectively block UV± light due to their high-energy bandgaps, while being transparent to visible light. These target compounds offer protection against high-energy light degradation, enhance the longevity and performance of materials exposed to high energy photons from sunlight, and provide safety benefits for UV+ exposure in various environments.II. UV+ Blocking Coating Composition and Associated Systems, Devices, and Methods

[0012] Figure 1 is a schematic illustration of a system 100 for creating a coating comprising a UV+ blocking compound, in accordance with embodiments of the present technology. In the illustrated embodiment, the system includes a substrate translation system configured to translate a substrate 102 to be coated with the coating 104. In various embodiments, the substrate 102 may comprise glass, polymer, or any other material requiring UV+ protection. The system further includes a deposition apparatus 106 configured to deposit a layer of one or more of the target compounds onto the substrate. For example, as the substrate 102 is translated beneath the deposition apparatus, the deposition apparatus deposits a stream of the coating material 108 of the one or more target compounds onto the substrate 102 to form the coating 104.

[0013] The UV+ blocking coating comprising at least one of the target compounds can be deposited and / or manufactured by various methods. For example, the deposition apparatus may be configured to deposit the UV+ blocking coating comprising at least one target compound via physical vapor deposition (PVD), sputtering, or solution processing. The UV+ blocking coating can be applied as a standalone layer or incorporated into a multilayer structure for additional functionalities, such as protective, anti -reflective, or self-cleaning properties.III. Experimental Results

[0014] Tests conducted on the UV+ blocking coatings comprising one or more of the target compounds have shown significant absorption in the UV+ spectral region with minimal absorption in the visible and near infrared (NIR) spectral range. These results indicate that such coatings can serve as effective UV+ filters while maintaining high transparency in the visible and NIR light spectrum.

[0015] Figures 2A (CsPb2Ch and CsPbCh) and 2B (Cs2AgBiBre) show optical absorption spectra for representative UV+ blocking coatings comprising one or more target compoundsdeposited on various substrates such as glass and fluoropolymers. The absorption onset for each material is less than 450 nm and shows strong absorption over the complete range of UV radiation (400-250 nm). There is minimal scattering at wavelengths longer than 450 nm, which is important for applications where light transmission is important (e.g., solar panels).

[0016] Figures 3A-3D show optical images of representative UV+ blocking coatings comprising one or more target compounds deposited on various substrates such as glass and fluoropolymers. Figure 3A depicts a CsPbChBr coating on flexible glass. Figure 3B depicts a CsPbCh coating on textured solar glass. Figure 3C depicts a Cs2AgBiBr6 coating on rigid glass. Finally, Figure 3D depicts a CsPbChBr coating on flexible fluorinated ethylene propylene (FEP) polymer. The highly transparent nature of these films makes them ideal for applications where the transmission of light with wavelengths greater than 450 nm is important (e.g., solar applications). Also, the films are sufficiently thin (e.g., no more than 1500 nanometers (nm), 1250 nm, or 1000 nm) that they can be applied to flexible substrates and still retain their optical properties. This could be beneficial for use in rollable solar arrays for a variety of applications (e.g., satellite solar arrays).IV. Examples

[0017] According to one example, a UV-blocking coating is provided. The UV-blocking coating includes a metal halide compound or alloy thereof. The metal halide compound comprises CsPbXs, CsPb2X5, Cs4PbX6, Cs2AgBiXe, or Cs2NaInXe, wherein X is Cl, Br, I, or a combination thereof. In an embodiment, X is Cl. In an embodiment, X is Br. In an embodiment, X is I.

[0018] In some embodiments, the coating comprises the metal halide compound or alloy thereof in the form of colloidal nanocrystals disposed in a transparent matrix.

[0019] The nanocrystals may have a shape selected from a sphere, rod, tetrapod, heteronanorod, hetero-platelet, hetero-tripod, hetero-tetrapod, hetero-hexapod, dot-in-rod, dot-in-platelet, rod-in-rod and platelet-in-platelet, dot-in-bulk, complex branched hetero- structure, or a combination thereof.

[0020] In some embodiments, the nanocrystals comprise a core and at least one shell.

[0021] In some embodiments, the nanocrystals are between 1 and 999 microns in size on average. In some embodiments, the nanocrystals are 1, 5, 10, 20, 30, 40, 50, 100, 150, 200, 250, 300,350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or 999 microns in size on average, or within a range defined by any two of these values. The average size may be determined by any method known in the art, including dry sieving and by microscopy.

[0022] In some embodiments, the nanocrystals are substantially non-aggregated.

[0023] In some embodiments, the nanocrystal concentration in the matrix may be from 0.01 wt % to 50 wt % relative to the weight of the transparent matrix, such as from 0.01 wt % to 0.5 wt %, or from 0.1 wt % to 0.2 wt %. In some embodiments, the nanocrystal concentration is 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt %, or within a range defined by any two of these values.

[0024] In an embodiment, the coating comprises the metal halide compound or alloy thereof in an amount of 1-100% by weight. In an embodiment, the coating comprises the metal halide compound or alloy thereof in an amount of 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 95, 99, 99.9, or 100% by weight, or within a range defined by any two of these values.

[0025] In an embodiment, the metal halide compound is selected from the group consisting of CsPb2Cl5, CsPbCh, Cs2AgBiBre, and CsPbChBr, and any combination thereof.

[0026] In an example embodiment, the coating exhibits significant absorption in the ultraviolet (400 nm-100 nm) and higher energy region (<100 nm) and minimal absorption in the visible and nearinfrared light regions (>400 nm). As used herein, “significant” absorption refers to at least 60% absorption, and “minimal” absorption refers to at most 40% absorption.

[0027] In an example embodiment, the coating absorbs at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.5%, at least 99.9%, at least 99.99%, or substantially all light at a high energy wavelength. A “high energy wavelength” is a wavelength of 400 nm or less. In an embodiment, the high energy wavelength is about 400, about 390, about 380, about 370, about 360, about 350, about 340, about 330, about 320, about 310, about 300, about 290, about 280, about 270, about 260, about 250, about 240, about 230, about 220, about 210, about 200, about 190, about 180, about 170, about 160, about 150, about 140, about 130, about 120, about 110, about 100, about 90, about 80, about 70, about 60, or about 50 nm,or any combination thereof, or within a range defined by any two of these values. In embodiments, the absorbance is measured at 1-10 high energy wavelengths.

[0028] In an example embodiment, the coating absorbs at most 40%, at most 35%, at most 30%, at most 25%, at most 20%, at most 15%, at most 10%, at most 9%, at most 8%, at most 7%, at most 6%, at most 5%, at most 4%, at most 3%, at most 2%, at most 1%, at most 0.5%, at most 0.1%, at most 0.01%, or substantially no light at a low energy wavelength. A “low energy wavelength” is a wavelength of greater than 400 nm but no more than 1400 nm. In an embodiment, the low energy wavelength is about 410, about 420, about 430, about 440, about 450, about 460, about 470, about 480, about 490, about 500, about 510, about 520, about 530, about 540, about 550, about 560, about570, about 580, about 590, about 600, about 610, about 620, about 630, about 640, about 650, about660, about 670, about 680, about 690, about 700, about 710, about 720, about 730, about 740, about750, about 760, about 770, about 780, about 790, about 800, about 810, about 820, about 830, about840, about 850, about 860, about 870, about 880, about 890, about 800, about 810, about 820, about830, about 840, about 850, about 860, about 870, about 880, about 890, about 900, about 910, about920, about 930, about 940, about 950, about 960, about 970, about 980, about 990, about 1000, about 1010, about 1020, about 1030, about 1040, about 1050, about 1060, about 1070, about 1080, about1090, about 1100, about 1110, about 1120, about 1130, about 1140, about 1150, about 1160, about1170, about 1180, about 1190, about 1200, about 1210, about 1220, about 1230, about 1240, about1250, about 1260, about 1270, about 1280, about 1290, about 1300, about 1310, about 1320, about1330, about 1340, about 1350, about 1360, about 1370, about 1380, about 1390, or about 1400, or any combination thereof, or within a range defined by any two of these values. In embodiments, the absorbance is measured at 1-10 low energy wavelengths.

[0029] In an example embodiment, the coating is on a substrate selected from the group consisting of glass and / or polymers. In an embodiment, the substrate is a solar panel or eyewear.

[0030] In an example embodiment, the coating further includes one or more additional layers to impart multifunctional properties.

[0031] In an example embodiment, the coating has a thickness of at most 1500 nm. In a further embodiment, the coating has a thickness of at most 1450, at most 1400, at most 1350, at most 1300, at most 1250, at most 1200, at most 1150, at most 1100, at most 1050, at most 1000, at most 950, atmost 900, at most 850, at most 800, at most 750, at most 700, at most 650, at most 600, at most 550, or at most 500 nm.

[0032] In an embodiment, the transparent matrix is a polymer matrix, a glass matrix, a sol-gel matrix, a solvent matrix, or a combination thereof.

[0033] In some embodiments, the transparent matrix comprises a polymer that is at least partially, and may be substantially, transparent to the light, such as visible light, IR light, UV light or combinations thereof. The transparent matrix may comprise a polymer suitable for processing into any desired form, such as a planar substrate or self-standing bulk material, a coating film such as for a coating on glass of plastic substrates, intercalated layer such as between two glass or plastic slabs, a fiber such as an optical fiber made of polymeric materials (plastic optical fiber) or a viscous fluid suitable for use in transparent packaging. In some embodiments, the transparent matrix is a polymer matrix suitable for use in a semi-transparent or substantially transparent window.

[0034] In some examples, the polymer matrix comprises a polymer selected from poly acrylate and poly acryl methacrylate, polyolefin, poly vinyl, epoxy resin (polyepoxide), polycarbonate, polyacetate, polyamide, polyurethane, polyketone, polyester, polycyanoacrylate, silicone, polyglycol, polyimide, fluorinated polymer, polycellulose, or poly oxazine. Exemplary polymers include, but are not limited to, polyethylene, polypropylene, polymethylpentene, polybutene-1, polyisobutylene, ethylene propylene rubber, ethylene propylene diene monomer rubber, polyvinyl chloride, polybutadiene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyacrylonitrile, bisphenol-A, bisphenol-F, polytetrafluoroethylene, polyvinylfluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, ethylene-carbon monoxide co-polymer, polyglycolide, polylactic acid, polycaprolactone, polyhydroxyalkanoate, polyhydroxybutyrate, polyethylene adipate, polybutylene succinate, polyethylene glycol, methyl cellulose, hydroxyl methyl cellulose, polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, polylauryl methacrylate or combinations thereof.

[0035] In some embodiments, the polymer matrix comprises an acrylate polymer, and may be an alkyl acrylate polymer. The acrylate polymer may also be a substituted acrylate polymer, where one or more of the vinyl hydrogens in the monomer is replaced by one or more substituent groups. In some embodiments, the substituent group is an alkyl group, such as methyl, ethyl, propyl, isopropyl, or butyl. Exemplary acrylate monomers that can be used to form the polymers include, but are notlimited to, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, lauryl acrylate, dodecyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, methyl methacrylate (MMA), ethyl methacrylate, butyl methacrylate, lauryl methacrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, or trimethylolpropane triacrylate (TMPTA). The acrylate or methacrylate monomer may be selected to provide long side chains, such as C6-C25 side chains, C8-C25 side chains or C10-C25 side chains. In some embodiments, the side chain group on the monomer is hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, lauryl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, or a combination thereof. In particular embodiments, the polymer matrix is polylauryl methacrylate (PMMA), which provides side chains having a length of C12.

[0036] The polymer matrix may also comprise one or more cross-linking agents. A person of ordinary skill in the art will understand that the type of cross-linking agent may depend on the type of polymer being used. For example, a diacrylate cross-linking agent may be sued to cross link a polyacrylate polymer matrix. In some embodiments, the cross-linking agent is a diacrylate or dimethacrylate. The cross-linking agent may be an alkyl or alkyl oxide diacrylate or dimethacryalte, and in particular embodiments, the cross-linking agent is ethylene glycol dimethacrylate.

[0037] The nanocrystals may be dispersed in the polymer matrix. In some embodiments, the nanocrystals are dispersed in the polymer matrix by a process that inhibits or substantially prevents aggregation of the nanocrystals.

[0038] The coating may be a substantially colorless coating. In some embodiments, the coating has a color rendering index of greater than 80, such as from 80 to 100, from 85 to 100 or from 90 to 100. In other embodiments, the coating has a total error score from a Farnsworth-Munsell 100 hue color vision test of less than 100, such as from 0 to 90, from 0 to 80 or from 0 to 70, indicating an insignificant amount of color distortion being experienced by test subjects.

[0039] In some embodiments, the nanocrystals are mixed with a lower alcohol, a non-polar solvent and a sol-gel precursor material, and the resultant solution can be used to form a solid composition. For example, the solution can be deposited onto a suitable substrate to yield substantially homogeneous, solid compositions from the solution of nanocrystals and sol-gel precursor. “Homogeneous” means that the nanocrystals are substantially uniformly dispersed in the resultantproduct. In some instances, non-uniform dispersal of the nanocrystals is acceptable. In some embodiments of the invention, the solid compositions can be transparent or optically clear.

[0040] The lower alcohol used in this process is generally an alcohol containing from one to four carbon atoms, i.e., a Ci to C4 alcohol. Among the suitable alcohols are methanol, ethanol, n- propanol, isopropanol, n-butanol, sec-butanol and t-butanol.

[0041] The non-polar solvent is used in the process to solubilize the nanocrystals and should be miscible with the lower alcohol. The non-polar solvent is generally chosen from among tetrahydrofuran, toluene, xylene and the like. Tetrahydrofuran is a preferred non-polar solvent in this process.

[0042] Sol-gel processes generally refer to the preparation of a ceramic material by preparation of a sol, gelation of the sol and removal of the solvent. Sol-gel processes are advantageous because they are relatively low-cost procedures and are capable of coating long lengths or irregularly shaped substrates. In forming the sol-gel based solution used in the processes of the present invention, suitable sol-gel precursor materials are mixed with the other components.

[0043] Additional information regarding Sol-gel processes can be found in Brinker et al., “Sol- Gel Science, The Physics and Chemistry of Sol-Gel Processing”, Academic Press, 1990, which is incorporated herein by reference. Among suitable sol-gel precursor materials are included metal alkoxide compounds, metal halide compounds, metal hydroxide compounds, combinations thereof and the like where the metal is a cation from the group of silicon, titanium, zirconium, and aluminum. Other metal cations such as vanadium, iron, chromium, tin, tantalum and cerium may be used as well. Sol solutions can be spin-cast, dip-coated, printed or sprayed onto substrates in air. Sol solutions can also be cast into desired shapes by filling molds or cavities as well. Among the suitable metal alkoxide compounds can be included titanium tetrabutoxide (titanium (IV) butoxide), titanium tetraethoxide, titanium tetraisopropoxide, zirconium tetraisopropoxide, tetraethoxysilane (TEOS). Among suitable halide compounds can be included titanium tetrachloride, silicon tetrachloride, aluminum trichloride and the like.

[0044] The sol-gel based solutions generated in this process are highly processable. They can be used to form solid compositions in the shape of planar films and can be used to mold solid compositions of various other shapes and configurations. Volume fractions or loadings of thenanocrystals can been prepared as high as about 13 percent by volume and may be as high as up to about 30 percent by volume. Further, the first process of the present invention has allowed preparation of solid compositions with a refractive index of 1.9, such refractive index values being tunable.

[0045] In alternative embodiments, the process for incorporating nanocrystals into a sol-gel host matrix further comprises admixing the nanocrystals with a polymer. Typically this is done in a suitable solvent, such as a solvent that will dissolve the polymer. A person of ordinary skill in the art will understand that the nature of the solvent will depend on the polymer which needs to be dissolved. Suitable solvents include, but are not limited to, chlorinated solvents such as chloroform, dichloromethane, di chloroethane and tetrachloroethane. The polymer solution is then added to a solution of nanocrystals in a suitable solvent, such as chloroform. In some embodiments, the nanocrystals have been previously separated from their growth media, such as by precipitation. When sufficient polymer has been added such that the nanocrystals are soluble in an alcohol, such as ethanol, the solvent is evaporated. The nanocrystal / polymer mixture is dissolved in alcohol, typically in an inert atmosphere. In some instances where minor amounts of nanocrystal-polymer adduct or complex remained un-dissolved in the alcohol, a co-solvent such as tetrahydrofuran and the like is used with the alcohol to completely or nearly completely solubilize the adduct or complex. The solution is then mixed with a sol-gel precursor solution, e.g., a titania sol precursor material, and formed into a solid composite such as a film on a substrate. Once incorporated into the sol-gel matrix, the nanocrystals are highly stable and are not then soluble within hydrocarbon solvents such as hexane. The alcohols, used with the alcohol soluble colloidal nanocrystal-polymer adduct or complexes in the present invention, generally include ethanol, 1 -propanol and 1 -butanol. Other alcohols may be used as well, but alcohols having lower boiling points are preferred for improved processability with sol-gel precursors.

[0046] Additional information regarding the process of preparing a composition comprising nanocrystals dispersed within a sol-gel host matrix can be found in U.S. Pat. Nos. 7,226,953, 7,723,394 and 8,198,336, which are incorporated herein by reference.

[0047] In alternative embodiments, the nanocrystals are dispersed in a solvent matrix. The solvent can be any solvent suitable for solubilizing the nanocrystals. Suitable solvents include nonpolar solvents, such as tetrahydrofuran, toluene, xylene and the like. The solvent may be a single solvent, or it may be a mixture of solvents. A composition comprising a solvent matrix may be usedwhen the composition will be loaded into a space between two layers, typically transparent layers. Examples include, but are not limited to, loading the composition into the space between two panes of glass, such as two window panes.

[0048] Also disclosed herein are embodiments of a method for making the composition. In some embodiments, the method comprises mixing the nanocrystals with a small volume of a monomer, and then mixing the resulting mixture with a larger volume of the monomer. One or more cross-linking agents and / or initiators may also be added. In some embodiments, the nanocrystals are mixed with the small volume of monomer for a time sufficient to wet the surfaces of the nanocrystals and / or allow for a fine dispersion of nanocrystals in the monomer to develop. Suitable cross-linking agents include any agent that can cross-link the polymer being made. A person of ordinary skill in the art will understand that the exact nature and amount of the cross-linking agent may depend on the monomer being used. In certain embodiments, an acrylate cross-linker is used, such as ethylene glycol dimethacrylate. The amount of cross-linking agent is selected to provide a desired amount of crosslinking in the resultant polymer. In some embodiments, the ratio of monomer to cross-linking agent is from less than 50%:50% wt / wt to greater than 99%: 1% wt / wt, such as from 60%:40% wt / wt to 99%: 1% wt / wt, from 75% :25% wt / wt to 95% : 5% wt / wt or from 70%:30% wt / wt to 90%: 10% wt / wt. In certain embodiments, the ratio of monomer to cross-linking agent is 80%:20% wt / wt.

[0049] An initiator may be used to facilitate polymerization of the monomer. The initiator can be any initiator suitable for the particular monomer being used. In some embodiments, the initiator is a radical photoinitiator. Suitable initiators include, but are not limited to, peroxides such as lauroyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, tert-butyl peracetate, tert-butyl hydroperoxide and acetone peroxide, azo compounds such as azobisisobutyronitrile (AIBN), l,r-azobis(cyclohexanecarbonitrile) (ABCN) and 4,4 '-azobi s(4- cyanovaleric acid) (ABVA), photoinitiators such as 2,2-dimethoxy-l,2-diphenylethan-l-one (IRGACURE® 651), persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, organometallics such as triethylaluminum and titanium tetrachloride, or combinations thereof. Sufficient initiator is added to the monomer to initiate the polymerization reaction. In some embodiments, the amount of initiator added to the monomer or monomers is from greater than 0 to greater than 5% wt / wt with respect to the monomer(s), such as from greater than 0 to 5% wt / wt, from0.1% to 2.5% wt / wt, or from 0.5% to 1.5% wt / wt. In certain embodiments, 1% wt / wt initiator is added to the monomer(s).

[0050] After the nanocrystal / monomer mixture has been mixed with the larger volume of monomer, and any desired cross-linking agents and / or initiators added, the mixture is agitated to facilitate nanocrystal dispersion. Any suitable agitation can be used, such as stirring, sonication, shaking or any combination thereof. The agitation is continued until a suitable dispersion is formed. The mixture is then typically poured into a mold and polymerization is initiated. The polymerization can be initiated by any suitable technique, such as heating or irradiation, and may proceed in a light or a dark environment, and at an ambient temperature or an elevated or reduced temperature relative to the ambient temperature. A person of ordinary skill in the art will appreciate that the method of initiation may depend on the type of initiator used. In certain embodiments, the initiation was achieved by irradiation, such as UV irradiation. After polymerization is complete, the composition can be removed from the molds, shaped or cut in to a desired shape, and polished.

[0051] In an embodiment, the matrix absorbs at most 40%, at most 35%, at most 30%, at most 25%, at most 20%, at most 15%, at most 10%, at most 9%, at most 8%, at most 7%, at most 6%, at most 5%, at most 4%, at most 3%, at most 2%, at most 1%, at most 0.5%, at most 0.1%, at most 0.01%, or substantially no light at at least one low energy wavelength or high energy wavelength.

[0052] According to another example, a method for producing a UV-blocking coating is provided. The method includes depositing onto a substrate a layer of CsPbXs, CsPbsXs, Cs4PbXe, Cs2AgBiXe, and / or Cs2NaInX6, wherein X is Cl, Br, I, or a combination thereof. In an embodiment, X is Cl. In an embodiment, X is Br. In an embodiment, X is I.

[0053] In an example embodiment, the deposition is performed by a technique comprising physical vapor deposition, thermal evaporation, and / or solution processing.

[0054] In an example embodiment, the method further includes depositing one or more additional layers to impart multifunctional properties. In an example embodiment, the additional layer is flexible.

[0055] According to another example, a UV-blocking substrate is provided. The UV-blocking substrate includes a translucent substrate; and a UV-blocking coating disposed on the translucentsubstrate. The UV-blocking coating comprises at least one of CsPbX , CsPb2Xs, Cs4PbXe, Cs2AgBiXe, or Cs2NaInXe, and X is Cl, Br, I, or a combination thereof.

[0056] In an example embodiment, the UV-blocking substrate exhibits significant absorption in the ultraviolet (400 nm-100 nm) and higher energy region (<100 nm) and minimal absorption in the visible and near-infrared light regions (>400 nm).

[0057] In an example embodiment, the translucent substrate is selected from the group consisting of glass and / or polymers.

[0058] In an example embodiment, the UV-blocking substrate further includes one or more additional layers to impart multifunctional properties.

[0059] In some embodiments, the UV-blocking substrate is a laminate. For laminates, a solid UV-blocking coating layer as described hereinabove is formed separately, and then adhered to the translucent substrate. As a non-limiting example, a UV-blocking coating layer may be formed by solution processing on a non-adhering surface, such as teflon; the UV-blocking coating layer may then be separated from the non-adhering surface and put in contact with the substrate prior to adhesion. The adhesion may be any suitable method known in the art, including via heat, pressure, adhesive, or any combination thereof.

[0060] In some embodiments, the UV-blocking coating completely or partially encapsulates the substrate. In the embodiment where the UV-blocking coating completely encapsulates the substrate, none of the substrate’ s surface area is exposed. In the embodiments where the UV-blocking coating partially encapsulates the substrate, the portion of the substrate’s surface area is exposed. For example, if the UV-blocking coating encapsulates 90% of the substrate, 10% of the substrate’s surface area remains exposed. In embodiments, the UV-blocking coating encapsulates at least 60, at least 70, at least 75, at least 80, at least 85, at least 90, at least 91, at least 92, at least 93, at least 94, at least 95, at least 96, at least 97, at least 98, at least 99, at least 99.5, at least 99.9%, or 100% of the surface area of the substrate.

[0061] A particularly beneficial use of the coatings of the invention is as encapsulants for solar panels. An encapsulant layer (or layers) in a solar panel serves to shield the components of the solar panel from moisture, dirt, and other pollutants. The solar panel will generally comprise a layer of solar cells with a protective layer (such as glass) disposed on the top side (the side to be directed atsunlight). In an embodiment of the invention, a UV-blocking coating layer is disposed on the top side of the solar cells, between the solar cells and the protective layer. In an embodiment, the UV-blocking coating layer serves to adhere the solar cells to the protective layer. In an embodiment, a second UV- blocking coating layer is also disposed on the bottom side of the solar cells (the side opposite the protective layer). In some embodiments, the second UV-blocking coating layer is different from the first UV-blocking coating layer; the difference may be in the metal halide compound or alloy thereof, the matrix, the concentration of the metal halide compound or alloy thereof in the matrix, or a different property. It is not critical that the second UV-blocking coating layer be transparent.

[0062] Additional information on substrates for coatings, and particularly nanocrystal-based coatings, may be found in U.S. Pat. No. 11,168,225, which is hereby incorporated by reference in its entirety.V. Conclusion

[0063] The described UV+ blocking coatings and / or target compounds described herein provide a cost-effective and efficient solution for protecting materials from high energy light. With potential applications ranging from protective coatings for solar cells to eyewear, such as safety eyewear, the coatings offer broad utility across various industries.

[0064] From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

Claims

CLAIMSI / We claim:

1. A UV-blocking coating comprising a metal halide compound or alloy thereof, wherein the compound comprises CsPbXs, CsPb2Xs, Cs4PbXe, Cs2AgBiXe, or Cs2NaInXe, wherein X is Cl, Br, I, or a combination thereof.

2. The UV-blocking coating of claim 1, wherein the coating exhibits significant absorption in the ultraviolet (400 nm-100 nm) and higher energy region (<100 nm) and minimal absorption in the visible and near-infrared light regions (>400 nm).

3. The UV-blocking coating of claim 2, wherein the coating absorbs at least 60% of light at a wavelength of 400 nm or less.

4. The UV-blocking coating of claim 2, wherein the coating absorbs at most 40% of light at a wavelength of greater than 400 nm and no more than 1400 nm.

5. The UV-blocking coating of claim 1, wherein the coating on a substrate selected from the group consisting of glass and / or polymers.

6. The UV-blocking coating of claim 1, further comprising additional layers to impart multifunctional properties.

7. The UV-blocking coating of claim 1, wherein the coating comprises the metal halide compound or alloy thereof in the form of colloidal nanocrystals disposed in a transparent matrix.

8. The UV-blocking coating of claim 1, wherein the matrix is a polymer matrix, a glass matrix, a sol-gel matrix, a solvent matrix, or a combination thereof.

9. A method for producing a UV-blocking coating, the method comprising:depositing onto a substrate a layer of CsPbXs, CsPb2Xs, Cs4PbXe, Cs2AgBiXe, and / or Cs2NaInXs, wherein X is Cl, Br, I, or a combination thereof.

10. The method of claim 9, wherein the deposition is performed by a technique comprising physical vapor deposition, thermal evaporation, and / or solution processing.

11. The method of claim 9, further comprising depositing one or more additional layers to impart multifunctional properties.

12. A UV-blocking substrate comprising: a translucent substrate; and a UV-blocking coating disposed on the translucent substrate, the UV-blocking coating comprising at least one of CsPbXs, CsPb2Xs, Cs4PbXe, Cs2AgBiXe, or Cs2NaInXe, wherein X is Cl, Br, I, or a combination thereof.

13. The UV-blocking substrate of claim 12, wherein the UV-blocking substrate exhibits significant absorption in the ultraviolet (400 nm-100 nm) and higher energy region (<100 nm) and minimal absorption in the visible and near-infrared light regions (>400 nm).

14. The UV-blocking substrate of claim 12, wherein the translucent substrate is selected from the group consisting of glass and / or polymers.

15. The UV-blocking substrate of claim 12, further comprising one or more additional layers to impart multifunctional properties.

16. The UV-blocking substrate of claim 12, formed by laminating a translucent substrate layer and a UV-blocking coating layer.

17. The UV-blocking substrate of claim 12, wherein the translucent substrate is a component of a solar panel.

18. The UV-blocking substrate of claim 12, wherein the solar panel comprises the UV- blocking coating as an encapsulant layer.

19. The UV-blocking substrate of claim 18, wherein the solar panel comprises a solar cell layer; a protective layer; and the UV-blocking coating layer disposed between the solar cell layer and the protective layer.

20. The UV-blocking substrate of claim 19, further comprising a second UV-blocking coating layer on the side of the solar cell layer opposite the first UV-blocking coating layer.

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