CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of Provisional Application No. 63/192,393, filed May 24, 2021 , which is incorporated herein by reference in its entirety for all purposes.

FIELD

[0002] The present disclosure relates generally to photoluminescent composites. More specifically, the disclosure relates to photoluminescent composites including diffuse reflecting microporous membranes and luminophores for modulating reflected light and a method for manufacturing the same.

BACKGROUND

[0003] Light modulation through the use of luminophores, such as quantum dots, phosphors, transition metal complexes, etc., has been a useful method for increasing the output of photovoltaics including sensors and solar cells by shifting the wavelength of incident sunlight. Additionally, light modulation can be used with both natural and artificial light systems, to shift the wavelength of emitted or reflected light to reduce heat, photonically cool, alter color and/or alter the amount of UV radiation emitted for a variety of applications.

SUMMARY

[0004] A photoluminescent composite comprising at least one diffuse reflecting microporous membrane layer, an optional substrate layer, and a luminophore disposed substantially in and optionally on the microporous membrane is provided. Here, diffuse reflecting is taken to mean that the reflection of light, light waves or light particles are reflected from a surface such that a ray incident on the surface is scattered at many angles rather than at just one angle as in the case of specular reflection. As such, any specular or collimated light incident upon the surface is substantially diffused and spread over multiple angles. The photoluminescent composite is configured to reflect and modulate light and may be used in a number of applications including agricultural environments, solar modules, agricultural lighting systems including LEDs, and other settings in which incident light is reflected. [0005] According to an embodiment of the present disclosure, a photoluminescent composite comprises a diffuse reflecting microporous membrane layer having a first side exposed to incident light and a second side opposite the first side; and a luminophore disposed within the microporous membrane layer. In a variation thereof, a concentration of the luminophore in the microporous membrane layer decreases from the second side to the first side. In another variation thereof, the photoluminescent composite further comprises a substrate layer coupled to the second side of the microporous membrane layer. In a further variation thereof, the substrate layer comprises at least one of a polymer, a metal, a woven fabric, a non-woven fabric, wood, and a surface of a structure. In a further variation thereof, the microporous membrane layer comprises a fluoropolymer. In a still further variation thereof, the microporous membrane layer comprises expanded polytetrafluoroethylene.

[0006] In yet another variation thereof, the microporous membrane layer comprises a woven or nonwoven polyolefin. In a further variation thereof, the microporous membrane layer has a porosity from 50% to 99%. In a still further variation thereof, the microporous membrane layer is loaded with 0.5 g/m ² to 50 g/m ² of the luminophore. In yet a further variation thereof, the photoluminescent composite is configured to reflect light onto a solar cell and generate power from 80 W/m ² to 260 W/m ² In a further variation thereof, the generated power is from 80 W/m ² to 200 W/m ² . In still a further variation thereof, the generated power is from 80 W/m ² to 150 W/m ² . In yet a further variation thereof, the composite has a luminophore photosynthetic efficiency from 1 ,000 molecules CO2 consumed per second/(g/m ² luminophore) to 65,000 molecules CO2 consumed per second/(g/m ² luminophore). In another variation thereof, the luminophore is configured to shift a wavelength of a reflected light. In still another variation thereof, the photoluminescent composite is configured to diffuse reflected light from an LED.

[0007] According to another embodiment of the present disclosure, a method of producing a photoluminescent composite comprises the steps of applying a luminophore to a first side of a microporous membrane layer such that a concentration of the luminophore at the first side of the microporous membrane layer exceeds a concentration of the luminophore at a second side of the microporous membrane layer; and after the applying step, coupling the first side of the microporous membrane layer to a support layer.

[0008] In a variation thereof, the applying step involves imbibing, spray coating, dip coating, painting, slot die, kiss coating, vapor coating, or vacuum pulling the luminophore onto the microporous membrane layer. In a further variation thereof, the applying step increases a power per area output of the photoluminescent composite.

[0009] According to another embodiment of the present disclosure, a photoluminescent composite comprises a substrate layer; a microporous membrane layer having a first side exposed to incident light and a second side coupled to the support layer; and a luminophore loaded in the microporous membrane layer at a concentration of 0.5 g/m ² to 50 g/m ² In a variation thereof, the luminophore is one of a phosphor, a fluorophore, and a quantum dot or dye. In another variation thereof, the luminophore comprises particles with a diameter from 1 pm to 100pm. In yet another variation thereof, the luminophore comprises particles with a diameter from 1 nm to 999 nm. In still another variation thereof, the luminophore comprises particles with a diameter of less than 1 nm. In a further variation thereof, the luminophore is selected from the group consisting of cerium-doped yttrium aluminum garnet (CeYAG), zinc sulfide (ZnS), and strontium aluminate. In another variation thereof, the luminophore is pyranine or another fluorescent dye. In yet another variation thereof, the luminophore is selected from the group consisting of an indium phosphide (InP) quantum dot, a lead sulfide (PbS) quantum dot, and a lead selenide (PbSe) quantum dot. In still yet another variation thereof, the composite is configured to reflect light to generate a photocurrent into a photovoltaic cell. In another variation thereof, the composite is configured to reflect light onto a plant to improve its growth. In still another variation thereof, the composite is used to reflect light in a sensor. In yet another variation thereof, the composite is used to reflect light from an LED. In another variation thereof, the composite is configured to reflect light to generate power in a solar cell of at least 70 W/m ²

[00010] The foregoing Examples are just that and should not be read to limit or otherwise narrow the scope of any of the inventive concepts otherwise provided by the instant disclosure. While multiple examples are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature rather than restrictive in nature.

BRIEF DESCRIPTION OF THE DRAWINGS

[00011 ] The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the description serve to explain the principles of the disclosure.

[00012] FIG. 1 is a diagrammatic view of a first exemplary embodiment of a photoluminescent composite having a microporous membrane layer and a luminophore present throughout substantially the entire microporous membrane layer;

[00013] FIG. 2 is a diagrammatic view of a second exemplary embodiment of a photoluminescent composite having a microporous membrane layer and a luminophore concentrated inside the microporous membrane layer;

[00014] FIG. 3 is a diagrammatic view of a third exemplary embodiment of a photoluminescent composite having a microporous membrane layer and a luminophore concentrated outside the microporous membrane layer;

[00015] FIG. 4 is a flow diagram for a process of forming a composite of any of FIGS. 1-3;

[00016] FIG. 5 is an experimental example setup for testing composites of FIGS. 1-3;

[00017] FIG. 6 is an experimental example setup for analyzing data for testing composites of FIGS. 1-3;

[00018] FIG. 7 is a plot of photocurrent for different composites;

[00019] FIG. 8 is a plot of calculated CO2 output for different composites;

[00020] FIG. 9 is a plot of albedo over a period of days for an exemplary photoluminescent composite;

[00021] FIG. 10 is a plot of luminophore PV efficiency for different composites; and

[00022] FIG. 11 is a plot of luminophore photosynthetic efficiency for different composites.

DETAILED DESCRIPTION

Definitions and Terminology

[00023] This disclosure is not meant to be read in a restrictive manner. For example, the terminology used in the application should be read broadly in the context of the meaning those in the field would attribute such terminology.

[00024] With respect to terminology of inexactitude, the terms “about” and “approximately” may be used, interchangeably, to refer to a measurement that includes the stated measurement and that also includes any measurements that are reasonably close to the stated measurement. Measurements that are reasonably close to the stated measurement deviate from the stated measurement by a reasonably small amount as understood and readily ascertained by individuals having ordinary skill in the relevant arts. Such deviations may be attributable to measurement error, differences in measurement and/or manufacturing equipment calibration, human error in reading and/or setting measurements, minor adjustments made to optimize performance and/or structural parameters in view of differences in measurements associated with other components, particular implementation scenarios, imprecise adjustment and/or manipulation of objects by a person or machine, and/or the like, for example. In the event it is determined that individuals having ordinary skill in the relevant arts would not readily ascertain values for such reasonably small differences, the terms “about” and “approximately” can be understood to mean plus or minus 10% of the stated value.

Description of Various Embodiments

[00025] Referring first to FIG. 1 , an exemplary embodiment of a photoluminescent composite 100 is shown. The photoluminescent composite 100 is configured to reflect incident light L. Optionally, the photoluminescent composite 100 is also configured to alter the wavelength and/or intensity of the reflected light. The illustrative photoluminescent composite 100 includes a substrate layer 110 (which may also be referred to as a support layer), a microporous membrane layer 120, and a luminophore on and/or in the microporous membrane layer 120, each of which is described further below.

[00026] The substrate layer 110 of the photoluminescent composite 100 may function substantially as a structural member to support and provide sufficient strength to the microporous membrane layer 120 and to enable the photoluminescent composite 100 to function for its intended purpose in its intended operating environment or simply to enhance the reflection or luminescence of the composite. The illustrative substrate layer 110 has a first, upper layer 112 coupled to the microporous membrane layer 120 and a second, lower layer 114.

[00027] The substrate layer 110 may be constructed of a polymer, such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyparaxylyeneperfluoroalkoxy copolymer resin (PFA), and polyolefins, including polypropylene and polyethylene. The substrate layer 110 may also be constructed of a metal, a fabric (e.g., woven fabric, non-woven fabric), wood, inorganics such as cement, or another suitable material. In some embodiments, substrate layer 110 may comprise a surface of a structure or any physical system, such as a wall, floor, roof, rail, fence, etc. wherein the other layer or layers of composite 100 may be applied directly to the surface of the structure. The substrate layer 110 may be formed of a single material or multiple materials. The substrate layer 110 may be a single-layer structure or a multi layer structure. The substrate layer 110 may be rigid or flexible. The substrate layer 110 may be uniform across a given direction or non-uniform across that direction. The substrate layer 110 may be flat as in a sheet or a slab as shown in FIG. 1 , a roll, or any other desired shape, including curved surfaces and three-dimensional objects. The substrate layer 110 may be configured to maintain intimate contact or contacts with the microporous membrane layer 120 such that the separation between the substrate layer 110 and the microporous membrane layer 120 is less than the thickness of the microporous membrane layer 120. In certain embodiments, the substrate layer 110 may be omitted if unnecessary to support the microporous membrane layer 120.

[00028] The microporous membrane layer 120 of the photoluminescent composite 100 functions substantially as a reflector of solar radiation or other incident light L. The illustrative microporous membrane layer 120 has a first, upper side 122 that faces the incident light L and a second, lower side 124 that faces the substrate layer 110.

[00029] The microporous membrane layer 120 may be constructed of a polymer, such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), polyparaxylyeneperfluoroalkoxy copolymer resin (PFA), and/or polyolefins and/or hydrocarbons, including polypropylene and polyethylene. The microporous membrane layer 120 may comprise an expanded polymer, a gel, or a flash-spun polymer. In certain embodiments, the microporous membrane layer 120 may be formed by expanding the polymer to create a plurality of nodes interconnected by fibrils that cooperate to define micropores 126 therebetween, as described, for example, in US Patent No. 3,953,566 to Gore, US Patent No. 5,643,511 to Pluyter et al. (DSM),US Patent No. 5,814,405 to Branca, and US Patent No. 8,757,395 to Bacino, US Patent No. 9,926,416 to Sbriglia. For example, the microporous membrane layer 120 may include expanded PTFE (ePTFE). The thickness, porosity, and other features of the microporous membrane layer 120 may be optimized to enhance its optical properties. For example, the microporous membrane layer 120 may have a porosity from 10% to 99.5%, more specifically from 20% to 99%, more specifically from 30% to 99%, more specifically from 40% to 99%, more specifically from 50% to 99%, more specifically from 60% to 99%, more specifically from 55% to 65%, more specifically from 70% to 99%, more specifically from 80% to 99%, more specifically from 90% to 99%, more specifically form 95% to 99%.

[00030] The luminophore 130 of the photoluminescent composite 100 is configured to absorb energy and then emit that energy as light. The luminophore 130 may also be configured to shift at least a portion of the incident light L, and therefore may be referred to as a wavelength shifting material. As used herein, shifting light may be considered to mean altering the wavelength of light, such as inputting a first wavelength and reflecting/emitting a second wavelength. In some embodiments, luminophore 130 may reflect/emit a longer wavelength than the wavelength of the incident light L. The luminophore 130 may absorb the light L as soon as it contacts the photoluminescent composite 100 (i.e. before being reflected by microporous membrane layer 120) and/or after being reflected by microporous membrane layer 120.

[00031] In certain embodiments, a plurality of different luminophores 130 may be mixed together and/or separated in distinct layers, which may function as multiple wavelength shifting layers. Each layer may shift all of the incident light L, or each layer may shift certain spectrum portions of the incident light L while leaving other spectrum portions intact. For example, each layer may shift different spectrum portions of the incident light L into the optimum spectrum radiation range.

[00032] In use, the photoluminescent composite 100 may be part of an albedo reflector system used with solar or photovoltaic (PV) cells or modules, with the luminophore 130 shifting portions of spectrum components of solar radiation to a radiation range at which the PV cell or module operates more efficiently (e.g., 400 nm - 700 nm wavelengths). In certain embodiments, the luminophore 130 may be configured to down-shift short wavelength infrared radiation (SWIR) (e.g. radiation having 1100nm - 2400 nm wavelengths) into the optimum spectrum radiation range for the PV cell or module. In other embodiments, the luminophore 130 may be configured to up-shift ultraviolet (UV) radiation (e.g. far ultraviolet (FUV) radiation having 100 nm - 200 nm wavelengths, middle ultraviolet radiation (MUC) having 200 nm - 300 nm wavelengths, and/or near ultraviolet radiation having 300 nm - 400 nm wavelengths) into the optimum spectrum radiation range for the PV cell or module. The luminophore 130 can, for example up-shift wavelengths (e.g. from UV and blue portions of the spectrum) into the optimum spectrum radiation range.

[00033] Suitable luminophores 130 may include any material suitable for incorporation in/on a microporous membrane. Such materials include materials that span the range of sizes from microparticles though nanoparticles to atomic or molecular entities. Certain embodiments of luminophores 130 as described herein include phosphors, fluorophores/molecular dyes, and quantum dots. Suitable luminophores 130 include phosphors including, but not limited to, cerium-doped yttrium aluminium garnet (CeYAG), zinc sulfide (ZnS), strontium aluminate, CdSe, CdS, CdTe, ZnSe, ZnTe, InN, InP, AIGaAs, InGaAs, CuS, Ag2S, CulnSe2, CulnS2, ln2S3S, GaP, InP, GaN, AIN, GaAs, PbS, PbSe, PbTe, CuCI, C112S, Cu2Se, Cu2ånSnS4, Cu2ZnSnSe4, Cii2ZnSnTe4, CulnTe ₂ , Si, Ge, Y2O3, Y2S3, Y ₂ Se ₃ , NaYF , NaYS ₂ , LaFs, YFs, ZnO, T1O2, La ₂ 0 ₂ S, Y2O2S, Gd202S, Z N2, Z P2, alloys thereof, heterostructures thereof, and any combination thereof as well as Europium or Doped Europium nanocluster and ligands, Zeolites incorporating nano or molecular composites of Silver or Europium in Nanoclusters, Atomic Quantum Clusters, and typical phosphors or microphosphors found in the lighting industry as described in US7112921 B2, US4512911A, and US6255670B1 , and any combination thereof. Suitable luminophores 130 also include fluorophores including, but not limited to, pyranine and other fluorescent dyes. Suitable luminophores 130 also include quantum dots, such as indium phosphide (InP), lead sulfide (PbS), and/or lead selenide (PbSe) quantum dots. Other suitable luminophores 130 include, for example, gypsum, calcite, quartz, orthoclase muscovite, kalinite, and rare earth materials (e.g. rare earth doped glass), as well as other material compounds including these materials. In certain embodiments, structures or materials of the types disclosed in US Patent 8,779,964 to Kelsey et al. may be included with luminophore 130.

[00034] The luminophore 130 may be provided as a powder. In certain embodiments, the luminophore 130 may include particles of 1 pm to 100 pm, more specifically 10 pm to 50 pm in diameter, more specifically 20 pm to 40 pm in diameter.

In other embodiments, the luminophore 130 may include particles of 1 nm to 999 nm in diameter. In other embodiments in which the luminophore 130 comprises quantum dots, the luminophore 130 may include particles of less than 1 nm to 10 nm in diameters, such as 2 nm to 10 nm in diameter.

[00035] The microporous membrane layer 120 may be loaded with a desired amount of the luminophore 130. In certain embodiments, the microporous membrane layer 120 may be loaded with the luminophore 130 at a surface area concentration (i.e., mass per unit area) of 0.5 g/m ² to 50 g/m ² , more specifically 2 g/m ² to 20 g/m ² , more specifically 5 g/m ² to 15 g/m ² .

[00036] The location and distribution of the luminophore 130 on and/or in the microporous membrane layer 120 may vary. In general, the luminophore 130 may be present on any nodes, on any fibrils, and/or within micropores 126 of the microporous membrane layer 120. The luminophore 130 may also be present on the upper side 122 and/or the lower side 124 of the microporous membrane layer 120. Various examples will now be described with reference to FIGS. 1-3. [00037] With reference to the photoluminescent composite 100 of FIG. 1 , the luminophore 130 is present throughout substantially the entire microporous membrane layer 120 (i.e., from the upper side 122 to the lower side 124 of the microporous membrane layer 120). In this embodiment, the incident light L may strike the polymer of the microporous membrane layer 120 and the luminophore 130 substantially simultaneously.

[00038] With reference to the photoluminescent composite 100’ of FIG. 2, the luminophore 130 is concentrated “inside” the photoluminescent composite 100’ near the lower side 124 of the microporous membrane layer 120 and the substrate layer 110. As shown on the left side of FIG. 2, the luminophore 130 may have an abrupt boundary 132 beyond which the concentration of the luminophore 130 decreases toward the upper side 122 of the microporous membrane layer 120. Alternatively, and as shown on the right side of FIG. 2, the luminophore 130 may gradually decrease in concentration toward the upper side 122 of the microporous membrane layer 120. In this embodiment, the incident light L generally strikes the polymer of the microporous membrane layer 120 before reaching the luminophore 130. Without wishing to be bound by theory, the present inventors believe that the light may enter the upper side 122 of the microporous membrane layer 120 and then become “trapped” in the microporous membrane layer 120 while also being exposed to the luminophore 130 for optimized reflectivity and/or light modulation. Also, the microporous membrane layer 120 may help protect the luminophore 130 without exposing the luminophore 130 along the upper side 122.

[00039] With reference to the photoluminescent composite 100” of FIG. 3, the luminophore 130 is concentrated “outside” the photoluminescent composite 100” near the upper side 122 of the microporous membrane layer 120. As shown on the left side of FIG. 3, the luminophore 130 may have an abrupt boundary 134 beyond which the concentration of the luminophore 130 decreases toward the lower side 124 of the microporous membrane layer 120. Alternatively, and as shown on the right side of FIG. 3, the luminophore 130 may gradually decrease in concentration toward the lower side 124 of the microporous membrane layer 120. In this embodiment, the incident light L may strike the polymer of the microporous membrane layer 120 and the luminophore 130 substantially simultaneously, similar to FIG. 1 .

[00040] Referring now to FIG. 4, a diagram of a method 400 for assembling the photoluminescent composites 100, 100’, 100” is shown. At block 402, the luminophore 130 is applied to the microporous membrane layer 120. At block 404, the microporous g membrane layer 120 is coupled to the substrate layer 110. The applying step of block 402 may be performed before or after the coupling step of block 404.

[00041] The applying step of block 402 may involve imbibing, spray coating, dip coating, painting, slot die, kiss coating, vapor coating, vacuum pulling, or otherwise applying the luminophore 130. The luminophore 130 may be applied to one or both sides 122, 124 of the microporous membrane layer 120. In the “inside” embodiment of FIG. 2, for example, the luminophore 130 may be applied to the lower side 124 of the microporous membrane layer 120 before the lower side 124 is coupled to the substrate layer 110.

[00042] The coupling step of block 404 may involve coating, laminating, adhering, molding, friction welding, stitching, weaving, or otherwise coupling the microporous membrane layer 120 to the substrate layer 110.

[00043] The photoluminescent composites 100, 100’, 100” (shown in FIGS 1, 2, and 3 respectively) may be used in a variety of settings for reflecting incident light L. As noted above, the photoluminescent composites 100, 100’, 100” may be used as albedo reflectors for reflecting solar radiation and may be used in conjunction with PV cells or modules for collecting solar energy. Embodiments of composites may be configured to reduce or minimize reflection of solar radiation having wavelengths (e.g. spectrum portions) that can negatively impact the operation of the PV cell or module. For example, the PV conversion or other operational efficiency of certain solar modules can be reduced or degraded when operated at relatively high temperatures. Therefore, luminophore 130 may be configured to filter heat-inducing spectrum portions from the solar radiation received by the photoluminescent composites 100, 100’, 100” and prevent the filtered spectrum portions from being reflected to the PV cell or module. In some embodiments, the photoluminescent composites 100, 100’, 100” can be configured to filter spectrum portions above 750 nm, above 1000 nm, above 1100 nm, or above 1200 nm.

[00044] The photoluminescent composites 100, 100’, 100” may also be configured to enhance the amount of radiation reflected by altering the isotropy of the diffused light. Certain embodiments of photoluminescent composites 100, 100’, 100” may also capture more global solar diffuse radiation over the course of a day and thereby enhance the amount of radiation directed towards a target surface. Furthermore, multiple such diffuse reflecting luminescent composites may be arranged spatially to bounce or sequentially reflect the incoming light and extend the effective solar day. The photoluminescent composites 100, 100’, 100” exhibit a diffuse reflective property (DRP) which is in contrast to the teachings of known luminescent compositions in the art including luminescent solar concentrators or enhanced solar mirrors. Both of these prior art concepts are designed to collimate, focus, and direct light to a target. In the case of solar concentrators, the transparency and non-diffuse translation of the radiation is paramount to transmission of light through their structure to a target. In the case of solar mirrors, the constructs are designed to focus light which often results in the need for complex tracking and movement. In contrast, the luminescent diffuse reflecting composites of the instant disclosure diffuse or spread the light, reducing hot spots and reducing the need for mechanical equipment which is of value in both agricultural and solar applications which may be in remote locations where complex machinery is prone to failure and disrepair. Other characteristics of the diffusing layer such as material composition, density, thickness, and/or structures of the layer can provide collimation enhancement properties.

[00045] The photoluminescent composites 100, 100’, 100” may also be used in artificial light settings, such as acting as diffuse reflectors for a light emitting diode (LED) module. For example, the photoluminescent composites 100, 100’, 100” may be used in conjunction with an LED module to generally improve efficiency of the LED radiation for plant growth. The disclosed photoluminescent composites 100, 100’, 100” or the luminophore 130 may be dispersed in or onto UV durable nanofibrillar structures. The nanofibrillar structures may be composed of fluoropolymers and perfluoropolymers, and polyolefins including, but not limited to, ePTFE.

[00046] Some embodiments of the photoluminescent composites 100, 100’, 100” described herein may be configured to reflect light to a standard PV cell or module to generate solar power from 50 W/m ² to 500 W/m ² , from 60 W/m ² to 400 W/m ² , from 70 W/m ² to 300 W/m ² , from 80 W/m ² to 300 W/m ² , from 80 W/m ² to 260 W/m ² from 80

W/m ² to 260 W/m ² , from 80 W/m ² to 200 W/m ² , from 80 W/m ² to 190 W/m ² , from 80

W/m ² to 180 W/m ² , from 80 W/m ² to 170 W/m ² , from 80 W/m ² to 160 W/m ² , from 80

W/m ² to 150 W/m ² , from 80 W/m ² to 140 W/m ² , from 80 W/m ² to 130 W/m ² , from 80

W/m ² to 120 W/m ² , or from 80 W/m ² to 110 W/m ² . In an exemplary embodiment, the photoluminescent composites 100, 100’, 100” reflect solar radiation to generate power of at least 70 W/m ² , at least 80 W/m ² , at least 90 W/m ² , at least 100 W/m ² , or more.

[00047] A photosynthetic action may also be calculated for the disclosed composites, wherein the solar radiation reflected from the photoluminescent composites 100, 100’, 100” can be converted into a photosynthetic output from a plant, which may be represented as uptake of CO2. In some embodiments, the composites generate a photosynthetic action of 50 to 500 molecules of CO2 per second, 70 to 200 molecules of CO2 per second, or 80 to 150 molecules of CO2 per second. In other embodiments, the photoluminescent composites 100, 100’, 100” generate a photosynthetic action of at least 80 molecules of CO2 per second, at least 90 molecules of CO2 per second, at least 100 molecules of CO2 per second, or more. The photoluminescent composites 100, 100’, 100” may have a luminophore photosynthetic efficiency from 1 ,000 molecules CO2 consumed per second per g/m ² luminophore to 65,000 molecules CO2 consumed per second per g/m ² luminophore.

[00048] Photoluminescent composites 100, 100’, and 100” may be described as diffuse reflectors. Here, diffuse reflecting is taken to mean that the reflection of light, light waves or light particles are reflected from a surface such that a ray incident on the surface is scattered at many angles rather than at just one angle as in the case of specular reflection. As such, any specular or collimated light incident upon the surface is substantially diffused and spread over multiple angles.

[00049] Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatuses configured to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not necessarily drawn to scale but may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawing figures should not be construed as limiting.

[00050] The photoluminescent composites 100, 100’, 100” shown in FIGS. 1-3 are provided as examples of the various features of the composites and, although the combination of those illustrated features is clearly within the scope of invention, that example and its illustration is not meant to suggest the inventive concepts provided herein are limited from fewer features, additional features, or alternative features to one or more of those features shown in FIGS. 1-3.

TEST METHODS

[00051] It should be understood that although certain methods and equipment are described below, other methods or equipment determined suitable by one of ordinary skill in the art may be alternatively utilized.

Thickness

[00052] Sample thickness was measured using a Keyence LS-7010M digital micrometer (Keyence Corporation, Mechelen, Belgium). Mass

[00053] Sample mass was measured using a Mettler-Toledo analytical balance model AG204.

Surface Area Density (Mass per Area)

[00054] The sample was cut to a well-defined surface area (e.g., w = 2.54 cm x I = 15.24 cm) using a die or any precise cutting instrument. The surface area density was calculated by dividing the measured mass by the surface area.

Volumetric Density

[00055] Volumetric density was calculated by dividing the measured mass by the volume according to the following formula: m

^P w - l - t in which p is density (g/cm ³ ), m is mass (g), w is width (cm), I is length (cm) and t is thickness (cm). The average of the three measurements was used.

Airflow

[00056] The airflow through the membranes was measured using a gas flow measurement system ATEQ D520 gas flow leak tester version 1.00 (ATEQ LES CLAYES SOUS BOIS France). The ATEQ was attached to a sample fixture with pneumatically seals an o-ring to a 1.92 cm diameter circular area of a 2.9 cm on a support screen. Airflow is then recorded in L/hr at a differential pressure of 0.174 psi (12 millibar). Air flow measured this way can be converted to other common units of measurement using the relation 164.6467/(L/hr ATEQ Value)=Gurley Second Value and Gurley Second Value=3.126/Frazier number.

Porosity

[00057] Porosity is expressed in percent porosity and was determined by subtracting the quotient of the average volumetric density of the article (described earlier herein) and that of the bulk density of PTFE (taken as 2.2 g/cm ³ ) from 1 , then multiplying that value by 100%.

Tensile Break Load Measurements and Matrix Tensile Strength [00058] Tensile break load was measured using an INSTRON 1122 tensile test machine equipped with flat-faced grips and a 0.445 kN load cell. The gauge length was 5.08 cm and the cross-head speed was 50.8 cm/min. The sample dimensions were 2.54 cm by 15.24 cm. For longitudinal MTS measurements, the larger dimension of the sample was oriented in the machine, or “down web, direction. For the transverse MTS measurements, the larger dimension of the sample was oriented perpendicular to the machine direction, also known as the cross web direction. Measurements were conducted at ambient pressure, relative humidity, and room temperature. Generally, this was 1 atmosphere, 25% relative humidity, and 21 °C. The thickness and mass of each sample was measured as described above. The samples were then tested individually on the tensile tester. Three different sections of each sample were measured. The average of the three maximum load (i.e., the peak force) measurements was used. The longitudinal and transverse MTS were calculated using the following equation: MTS= (maximum load/cross-section area) ^* (bulk density of PTFE)/density of the porous membrane), wherein the bulk density of PTFE is taken to be 2.2 g/cc. Porosity was expressed in percent porosity and was determined by Subtracting the quotient of the average density of the article (described earlier herein) and that of the bulk density of PTFE from 1 , then multiplying that value by 100%. For the purposes of this calculation, the bulk density of PTFE was taken to be 2.2 g/cc.

Albedo and Reflected Radiation

[00059] Measurement of albedo (ratio of reflected to input irradiance) to reflected radiation from the ground surface and measurement of the reflected surface power (W/m ² ). Albedometers were setup after specification in “ASTM E1918 - 16 Standard Test Method for Measuring Solar Reflectance of Horizontal and Low-Sloped Surfaces in the Field” with modifications as noted. A diagram of the setup can be seen in FIG. 5. Briefly two pairs of USB data logging pyranometers (Apogee Instruments, Logan, UT, Part No. SM-420P, ISO 9060:2018 Class C) were mounted with one facing up and one facing the ground using an albedometer bracket (Apogee Instruments, Logan, UT, Part No. AL-130). The bottom albedometer was limited to a field of view of 120 degrees by a black PET entry cone attached with electrical tape, and the top albedometer was used as received with a field of view of 180 degrees. The albedometer was mounted shown in FIG. 5 on a 1 inch diameter white PVC pipe 3.048 meters in length mounted 0.45m off the ground, the albedometers comprised of two pyranometers and an albedometer bracket were spaced 1.5048 M apart so each would pick up light from the depicted 1 5m diameter cone. The 3.048 m long mounting pipe was aligned north to south. A portable 20000 Ma/hr USB battery (Amazon Basics USA) was used to power the sensors and data was collected from the sensors using Apogee Connect software (Apogee Instruments, Logan, UT). The pyranometers were used as supplied with calibration by the manufacturer and were verified to match expected solar output using Clear Sky Calculator software (Apogee Instruments, Logan, UT) and demonstrated to give comparable readings within 0.1 % The two albedometers in FIG. 5 were run concurrently side by side for all quoted comparisons in the example allowing for a direct comparison of any measured difference.

[00060] Power readings were collected and logged every 15 minutes. The logged data from the up and down facing pyranometers was used to calculate the albedo as reflected solar radiation input from the 120° field of view to bottom pyranometer (W/m ² ). Input solar radiation to the corresponding top pyranometer (W/m ² ). Additionally, the cumulative power measured from the downward pyranometers was measured via integration of the power vs. time curves using Microsoft Excel.

Integrated Spectrally Resolved Total Reflectivity

[00061] FIG. 6 depicts a test setup used to measure integrated spectrally resolved total reflectivity. A 150 W UV Solar simulator (Solarlight, Glenside, PA, Model 16S-150-0.4-UV) configured for AMO simulation with 0.4cm beam diameter with no UV filters was mounted on an optical breadboard and directed via a 50.8mm diameter protected silver mirror (Thorlabs, Newton, NJ, Part No. PF20-03-p01) to a USB data logging pyranometer (Apogee Instruments, Logan, UT, Part No. SM-420P) pursuant to ISO 9060:2018 Class C and 1 m long UV-vis solarization resistant 1000um fiber optic input cable (Stellarnet, Inc., Tampa, FL, Part No. F1000-UWis-SRI-1). This fiber optic cable sent a fraction of the solar simulator light representing 1 sun at 1000W/m ² radiance based on the pyrometer to an integrating sphere (Ocean Optics, Largo, FL,

Part No. ISP-REF). This light was impinged on a sample on the integrating sphere with output from the integrating sphere taken via 1 m long UV-vis solarization resistant 1000um fiber optic input cable (Stellarnet, Inc., Tampa, FL, Part No. F1000-UVVis-SRI- 1) to a spectrometer (Stellarnet, Inc., Tampa, FL, BLACK-Comet) to collect the spectrum from 330nm to lOOOnm at 0.5nm resolution on a computer running appropriate software (Stellarnet, Inc., Tampa, FL, Stellarnet Spectrawiz Software, version 5.33) with a 146ms box car averaging (Stellarnet, Inc., Tampa, FL, BLACK- Comet). The integrating sphere was covered with a 3 mm thick wall 6x6x6 box of PETG with the top inner surface covered by a nanostructured coating (Nanolab, Waltham, MA, Singular Velvet Applique) to eliminate any background and reflection from the box. For each sample, spectrally resolved relative luminous reflectivity was measured and a dark background subtracted. The relative reflectivity was converted to absolute reflectivity by ratio with the spectra measured for a NIST-traceable halon reflectivity standard (Stellamet, Inc., Tampa, FL, Part No. RS50). Data for the 800-900nm region is interpolated as some sharp intense peaks from the xenon lamp saturate the detector pixels in these wavelengths on the spectrometer. As an example, the spectral reflectivity data was used to estimate the photocurrent versus wavelength and expected integrated power output from a solar cell receiving the reflected radiation from the samples. To do this, the spectral responsivity and IV curve for a standard reference solar cell (Abet Technologies, RR-109O) are used with the published AM1.5 solar reference spectrum.

[00062] Here the photocurrent at a given wavelength is given by the formula:

IscW = S(X) E(X) where Isc is the device short circuit current in amps, S(A) is the PV device spectral responsivity function [A m ² W ¹ nnr ¹ ] from the manufacturer, and E(l) is the AM1.5 reference spectrum of radiant power in [W nr ² nnr ¹ ] (from NREL per ASTM G-173-03 tables- https://www.nrel.aov/grid/solar-resource/spectra-am1.5.html accessed December 2020). The Isc is then calculated at each wavelength as attenuated by spectral reflectivity R(A).

IscW = S(X) E(X) R(X

To determine the predicted power output, the area under the wavelength vs photocurrent curve is integrated per the equation below calculated via numerical integration in plotting software such as QTI plot 1.0.0 (qtiplot.com by IONDEV SRL, Bucuresti, Romania) or JMP 14 (SAS software, Cary, NC).

[00063] Then using the integrated photocurrent Isc and the equation below the power output per unit area is estimated

P-max ⁼ Voc cFF where Voc is open circuit voltage, Isc is short circuit current, and FF is the fill factor. For the Abet reference standard PV cell used here Voc = 584mV and FF = 74.7, for a 4 cm ² area cell. This gives the expected current generated and reflected power output that can be converted to electricity via silicon-based PV semiconductor cell. The expected power output performance of exemplary composites can then be compared to the near perfect RS50 - halon reflection standard or other composites without luminophores.

Estimation of Photosynthetic Action Expected for a Typical Green Plant

[00064] In a similar fashion to the estimate of photocurrent generated by a PV cell based on wavelength modulation from the ASTM input solar spectrum, spectral response function, and Reflectivity, S (l) E(l) R(A) respectively, we can also estimate the predicted photosynthetic output of plants. Flere the photosynthetic action RA(l) at a given wavelength from a reflector surface using the photosynthetic action spectrum R(l) of a bean plant per (Balegh, S E, and Biddulph, O. Photosynthetic action spectrum of the bean plant. United States: N. p., 1970. Web. doi: 10.1104/pp.46.1 .1 .) digitized using Graph Digitizer 2.1 software (https://www.alnlni.com/Graph-D Igitizer/dt-l 0584.html).

PA (L) = P(; l) EQ l) L(l)

Flere E(l) is converted to units of photons nr ² s ¹ by multiplication with a conversion factor of 4.52 (photon nr ² s ^-1 / W nr ² nnr ¹ ). R(l) is the wavelength photosynthetic activity in molecules of CO2 consumed per 1000 incident photons per nm.

[00065] Via the equation below the photosynthetic action in terms of molecules of CO2 consumed per second is then determined by integrating the area under the wavelength vs the photocurrent curve via numerical integration to yield the number of molecules of CO2 per second produced from light reflected into a plant surface via a diffuse reflector.

EXAMPLES

[00066] For each of the following examples and comparative examples, the solar PV photocurrent estimate, power generation estimate, photosynthetic action estimate, PV efficiency, and photosynthetic efficiency were determined using the procedures outlined above. The results are summarized in Tables 1 and 2.

Example 1 - Y570 Phosphor at 8 g/m ² Inside

[00067] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop and placed on a 150mm glass vacuum filter funnel (Sterlitech, Seattle WA, Part No. 20500023). 0.14 grams of a commercial yellow CeYAG phosphor (PhosphorTech, Kenesaw, GA, Y570) with nominal particle size of 30 urn as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 8 g/m ² coverage using a vacuum filter flask. The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00068] This membrane was then placed with the coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD,

ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00069] This composite was then placed with the uncoated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 101.7 mA and the solar power generated by the cell at 110.9 W/m ² The estimated photosynthetic action for a typical green bean plant was 119.1 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 13.9 W/g of luminophore and a luminophore photosynthetic efficiency of 3293.8 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 2 - Y570 Phosphor at 4 g/m ² Inside

[00070] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1 .7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop and placed on a 150mm glass vacuum filter funnel (Sterlitech, Seattle, WA, Part No. 20500023). 0.07 grams of a commercial yellow CeYAG phosphor (PhosphorTech, Kenesaw, GA, Y570) with nominal particle size of 30 urn as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 4 g/m ² coverage using a vacuum filter flask. The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00071] This membrane was then placed coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00072] This composite was then placed with the uncoated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 104.1 mA and the solar power generated by the cell at 113.5 W/m ² . The estimated photosynthetic action for a typical green bean plant was 122.3 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 14.2 W/g of luminophore and a luminophore photosynthetic efficiency of 3381.3 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 3 - Y570 Phosphor at 8 g/m ² Outside

[00073] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1 .7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop and placed on a 150mm glass vacuum filter funnel (Sterlitech, Seattle, WA, Part No. 20500023). 0.14 grams of a commercial yellow CeYAG phosphor (PhosphorTech, Kenesaw, GA, Y570) with nominal particle size of 30 urn as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 8 g/m ² coverage using a vacuum filter flask. The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00074] This membrane was then placed coated side facing away from a substrate layer of another ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00075] This composite was then placed with coated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 100.3 mA and the solar power generated by the cell at 109.4 W/m ² . The estimated photosynthetic action for a typical green bean plant was 116.7 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 27.4 W/g of luminophore and a luminophore photosynthetic efficiency of 6454.5 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 4 - ZnS Phosphor at 15 g/m ² Inside

[00076] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop and placed on a 150mm glass vacuum filter funnel (Sterlitech, Seattle, WA, Part No. 20500023). 0.26 grams of a commercial zinc sulfide phosphor (Technoglow, Ennis, TX, Green Glow in the Dark & UV Powder, Part No. PZ3-GRN-S004Z) with nominal particle size of 20 urn as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 15 g/m ² coverage using a vacuum filter flask. The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00077] This membrane was then placed coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00078] This composite was then placed with the uncoated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 101.4 mA and the solar power generated by the cell at 110.5 W/m ² . The estimated photosynthetic action for a typical green bean plant was 119.9 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 7.4 W/g of luminophore and a luminophore photosynthetic efficiency of 1768.2 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 5 - ZnS Phosphor at 6 g/m ² Outside

[00079] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop and placed on a 150mm glass vacuum filter funnel (Sterlitech, Seattle, WA, Part No. 20500023). 0.26 grams of a commercial zinc sulfide phosphor (Technoglow, Ennis, TX, Green Glow in the Dark & UV Powder, Part No. PZ3-GRN-S004Z) with nominal particle size of 20 urn as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 6 g/m ² coverage using a vacuum filter flask. The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00080] This membrane was then placed coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00081] This composite was then placed with coated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 95.1 mA and the solar power generated by the cell at 103.8 W/m ² . The estimated photosynthetic action for a typical green bean plant was 112.6 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 6.9 W/g of luminophore and a luminophore photosynthetic efficiency of 1661.4 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 6 - Strontium Aluminate at 15 g/m ² Inside

[00082] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop and placed on a 150mm glass vacuum filter funnel (Sterlitech, Seattle, WA, Part No. 20500023). 0.1 grams of a commercial strontium aluminate phosphor (Technoglow, Ennis, TX, Strontium Aluminate Green Glow in the Dark & UV Powder, <35 Microns, Waterproof, Part No. PEN-GRN-S004Z) with nominal particle size of 30 um as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 15 g/m ² coverage using a vacuum filter flask The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00083] This membrane was then placed coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 um, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00084] This composite was then placed with the uncoated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 95.8 mA and the solar power generated by the cell at 104.5 W/m ² . The estimated photosynthetic action for a typical green bean plant was 109.9 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 13.1 W/g of luminophore and a luminophore photosynthetic efficiency of 3038.1 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 7 - Quantum Dots at 0.5 g/m ² Inside

[00085] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 2.54 um, porosity 65%, mass/area 1 .91 g/m ² , bubble point 112 psi, Matrix Tensile Strength 68956 psi MD / 68706 psi TD, ATEQ airflow 24 L/H, produced by the processes described in US Patent No. 8,757,395 to Bacino - was tensioned in a knitting hoop. Approximately 0.2 ml with 0.001g of InP/ZnS solid quantum dots stabilized with oleylamine ligands, fluorescence Aem 590 nm, 5 mg/mL in toluene (Millipore Sigma, Milwaukee, Wl, Part No. 776769) were coated onto the hooped membrane by placing in a line and drawing the solution across the hoop to produce a ~0.5g/m ² coverage coating. The hoop was removed allowed to air dry for 1 hour under convective airflow in a fume hood.

[00086] This membrane was then placed coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 um, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop. [00087] This composite was then placed with the uncoated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1 .5 solar induced photocurrent produced via a standard solar cell was estimated at 105.2 mA and the solar power generated by the cell at 114.7 W/m ² . The estimated photosynthetic action for a typical green bean plant was 124.8 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 229.4 W/g of luminophore and a luminophore photosynthetic efficiency of 55228.4 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Example 8 -Pyranine Highlighter Fluorescent Dye Inside

[00088] A luminescent diffuse reflector composite was produced. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1 .7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop. The cartridge from a yellow highlighter (EXP, Part No. EXP51100) was removed and squeezed to yield 1 ml of yellow fluorescent dyed ink reported in the literature to be an organic pyranine derivative. This 1 ml was spread over the membrane coating onto and into its surface. The hoop was removed from the flask assembly and allowed to air dry for 1 hour under convective airflow in a fume hood.

[00089] This membrane was then placed coated side facing a substrate layer of another ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and tensioned on a knitting hoop.

[00090] This composite was then placed with the uncoated side of the phosphor coated membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 93.8 mA and the solar power generated by the cell at 102.3 W/m ² . The estimated photosynthetic action for a typical green bean plant was 100 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 88.2 W/g of luminophore and a luminophore photosynthetic efficiency of 19081.4 molecules of CO2 sequestered per second for each g/m ² of luminophore. Example 9 - Albedo Reflector Y570 Phosphor at 4 g/m ² Inside

[00091] A luminescent diffuse reflector composite was produced and its effectiveness evaluated via outdoor Albedometery. An ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was laid over a 20inx30inchx3/16 white foam poster board (Elmers, Westerville, OH, Part No.

950041 T). 1.548 grams of a commercial yellow CeYAG phosphor (PhosphorTech, Kenesaw, GA, Y570) with nominal particle size of 30 urn as reported by the manufacturer was vortex mixed (VWR Vortex Mixer, Radnor, PA) in isopropyl alcohol and coated onto and into the membrane at 4 g/m ² using a 3oz central pneumatic hobby air brush (HarborFreight Tools, Camarillo, CA, Part No. 62294) at 6 inch separation distance and 30 psi pressure.

[00092] Another poster board was wrapped with 1 layer of ePTFE membrane - thickness 107 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566. Then, the coated membrane composite above was wrapped around it with the coated side facing the membrane.

[00093] 5 additional poster boards were produced in the same manner. These poster boards were then tiled in a 3x2 array and mounted under the albedometer setup described in FIG. 5. The albedo and reflected power were measured relative to Comparative Example 5 over a period of 5 days.

Comparative Example 1- ePTFE with no Phosphor

[00094] This comparative example is intended for comparison to Examples 1-6 and 8-9 above. A PTFE-only composite reflector was produced. A first ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca - was tensioned in a knitting hoop on a second ePTFE membrane - thickness 97.6 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566.

[00095] This composite was then placed with the first membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1 .5 solar induced photocurrent produced via a standard solar cell was estimated at 102.3 mA and the solar power generated by the cell at 111.6 W/m ² . The estimated photosynthetic action for a typical green bean plant was 119.9 molecules of CO2 sequestered per second.

Comparative Example 2 - ePTFE with no Phosphor

[00096] This comparative example is intended for comparison to Example 7 above. A PTFE-only composite reflector was produced. A first ePTFE membrane - a thickness 2.54 urn, porosity 65%, mass/area 1.91 g/m ² , bubble point 112 psi, Matrix Tensile Strength 68956 psi MD / 68706 psi TD, ATEQ airflow 24 L/H, produced by the processes described in US Patent No. 8,757,395 to Bacino - was tensioned in a knitting hoop and on top of a second ePTFE membrane - thickness 97.6um, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566.

[00097] This composite was then placed with the first membrane facing the integrating sphere and the spectra measured. Following the method described above, the estimated AM1 .5 solar induced photocurrent produced via a standard solar cell was estimated at 103.9mA and the solar power generated by the cell at 113.3 W/m ² . The estimated photosynthetic action for a typical green bean plant was 124.8 molecules of CO2 sequestered per second.

Comparative Example 3 - Y570 Phosphor Alone

[00098] A transparent ACLAR ^® 33 PCTFE film (Electron Microscopy Sciences, Hatfield, PA, Part No. 50425-10) having a thickness of 7.8 mil (199 pm) was placed on the integrating sphere opening and its reflectance spectrum measured. On top of this film were placed aluminum shims at about 200 microns tall next to the integrating sphere port (which is the equivalent thickness of the ePTFE membrane composites in prior examples). Onto this PCTFE film was piled 1g of a commercial yellow CeYAG phosphor (PhosphorTech, Kenesaw, GA, Y570) with nominal particle size of 30 urn.

This powder was scraped level with the shims to give a 200 micron tall layer of phosphor.

[00099] The reflectivity of this phosphor layer on the PCTFE film was then measured. The reflectivity of the phosphor layer alone was then calculated by subtraction of the minor reflectivity of the transparent PCTFE layer. The CeYAG phosphor had a measured tap density of 1 22g/cm ³ , and CeYAG has a literature reported true density of 4.6g/cm ³ . Accordingly, the phosphor coverage of this layer was 242 grams/m ² and the porosity of the packed phosphor layer was 73%. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 99.8 mA and the solar power generated by the cell at 108.9 W/m ² . The estimated photosynthetic action for a typical green bean plant was 116.5 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 0.4 W/g of luminophore and a luminophore photosynthetic efficiency of 106.5 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Comparative Example 4 - ZnS Phosphor Alone

[000100] A transparent ACLAR ^® 33 PCTFE film (Electron Microscopy Sciences, Hatfield, PA, Part No. 50425-10) having a thickness of 7.8 mil (199 pm) was placed on the integrating sphere opening and its reflectance spectrum measured. On top of this film were placed aluminum shims at about 200 microns tall next to the integrating sphere port (which is the equivalent thickness of the ePTFE membrane composites in prior examples). Onto this PCTFE film between the shims was piled 1 5g of a commercial zinc sulfide phosphor (Technoglow, Ennis, TX, Green Glow in the Dark & UV Powder, Part No. PZ3-GRN-S004Z) with nominal particle size of 20 urn. This powder was scraped level with the shims to give a 200 micron tall layer of phosphor.

[000101 ] The reflectivity of this phosphor layer on the PCTFE film was then measured. The reflectivity of the phosphor layer alone was then calculated by subtraction of the minor reflectivity of the transparent PCTFE layer. The ZnS phosphor had a measured tap density of 1 62g/cm ³ and ZnS has a literature reported true density of 4.09g/cm ³ . Accordingly, the phosphor coverage of this layer was 322 grams/m ² and the porosity of the packed phosphor layer was 60%. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 75.5 mA and the solar power generated by the cell at 82.3 W/m ² . The estimated photosynthetic action for a typical green bean plant was 85.6 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 0.3 watts per gram of luminophore and a luminophore photosynthetic efficiency of 58.8 molecules of CO2 sequestered per second for each gram per square meter of luminophore. Comparative Example 5 - Strontium Aluminate Phosphor Alone

[000102] A transparent ACLAR ^® 33 PCTFE film (Electron Microscopy Sciences, Hatfield, PA, Part No. 50425-10) having a thickness of 7.8 mil (199 pm) was placed on the integrating sphere opening and its reflectance spectrum measured. On top of this film were placed aluminum shims at about 200 microns tall next to the integrating sphere port (which is the equivalent thickness of the ePTFE membrane composites in prior examples). Onto this PCTFE film between the shims was piled 1.14 grams of a commercial strontium aluminate phosphor (Technoglow, Ennis, TX, Strontium Aluminate Green Glow in the Dark & UV Powder, <35 Microns, Waterproof, Part No. PEN-GRN-S004Z) with nominal particle size of 30 urn as reported by the manufacturer. This powder was scraped level with the shims to give a 200 micron tall layer of phosphor.

[000103] The reflectivity of this phosphor layer on the PCTFE film was then measured. The reflectivity of the phosphor layer alone was then calculated by subtraction of the minor reflectivity of the transparent PCTFE layer. The phosphor had a measured tap density of 1 29g/cm ³ , and strontium aluminate has a literature reported true density of 3.56g/cm ³ . Accordingly, the phosphor coverage of this layer was 258 grams/m ² and the porosity of the packed phosphor layer was 64%. Following the method described above, the estimated AM1.5 solar induced photocurrent produced via a standard solar cell was estimated at 79.9 mA and the solar power generated by the cell at 87.1 W/m ² The estimated photosynthetic action for a typical green bean plant was 92.9 molecules of CO2 sequestered per second. These estimates yield a luminophore PV efficiency of 0.3 W/g of luminophore and a luminophore photosynthetic efficiency of 79.7 molecules of CO2 sequestered per second for each g/m ² of luminophore.

Comparative Example 6 - Grass Albedo

[000104] The albedo for a 1.5 meter circle of native green lawn (primarily Kentucky bluegrass) was measured concurrently to the material in Example 10 for a sunny day during daylight hours 7am to 7pm in late July and the average albedo from the grass was measured as in the outdoor albedometry set up. The average albedo from the grass was measured as 0.207.

Comparative Example 7 - Albedo PTFE only

[000105] A PTFE only diffuse reflector composite was produced and its effectiveness evaluated via outdoor Albedometery. A 20inx30inchx3/16 white foam poster board (Elmers, Westerville, OH, Part No. 950041 T) was wrapped with a first layer of ePTFE membrane - thickness 107 urn, porosity 80%, mass/area 16.1 g/m ² , bubble point 22.56 psi, Matrix Tensile Strength 6144 psi MD / 16876 psi TD, ATEQ airflow 20 L/H, produced by the processes described in US Patent No. 3,953,566 - and then covered with a second ePTFE membrane - thickness 104 urn, porosity 98.4%, mass/area 3.74 g/m ² , bubble point 1.7 psi, Matrix Tensile Strength 444469 psi MD / 13574 psi TD, ATEQ airflow 767 L/H, produced by the processes described in US Patent No. 5,814,405 to Branca.

[000106] 5 additional poster boards were produced in the same way. These poster boards were then tiled in a 3x2 array and mounted under the albedometer setup described in FIG. 5 with the second membrane on the exterior. The albedo and reflected power were measured relative to Example 10 over a period of 4.5 days in Elkton, MA in September. The cumulative reflected power measured over this time was 36622.8 W/m ² with an input of 61280 W/m ² to the top sensor over the same period. The average albedo from this composite was 0.598.

Table 1 - Summary of Example Testing (Pt. 1)

Table 2 - Summary of Example Testing (Pt. 2)

Example Data Comparison

[000107] Referring first to Table 2, each of the experimental Examples 1 -8 demonstrated a significantly higher luminophore PV efficiency and photosynthetic efficiency when compared to each of the Comparative Examples 1-5. Each experimental example had efficiencies at least an order of magnitude higher than all comparative examples, indicating that in the experimental examples, the combination of luminophore with the membrane resulted in an improvement over just the luminophore or membrane alone.

[000108] Referring now to FIG. 7, a plot of the photocurrent output is plotted for just an ePTFE membrane alone (Comparative Example 1), just a Y570 phosphor alone (Comparative Example 3), the combination of the ePTFE membrane and Y570 phosphor with the luminophore at 4 g/m ² and positioned on the interior of the composite nearest the substrate layer (Example 2), the combination of the ePTFE membrane and Y570 phosphor with the luminophore at 8 g/m ² and positioned on the interior of the composite nearest the substrate layer (Example 3), and the combination of the ePTFE membrane and Y570 phosphor with the luminophore at 4 g/m ² and positioned on the exterior of the composite furthest from the substrate layer (Example 3).

[000109] Referring next to FIG. 8, the CO2 uptake in moles/sec is shown for each of the same five samples shown in FIG. 7. Each of these examples involves a membrane, a particular luminophore coating, or a combination of the two in varying configurations. The same luminophore was compared on the interior and exterior of the composite, and in varying concentrations on the interior. At higher concentrations, the luminophore coating travels further into the outermost layer of the composite. As can be seen in both FIGS. 7 and 8, Example 1 with demonstrated the highest photocurrent and CO2 uptake compared to the other comparable examples. Compared to Example 2, Example 1 had more luminophore penetrate the membrane layer to generate the concentration gradient of luminophore in the membrane as discussed herein. This result indicates that given the same luminophore, performance is improved if the luminophore is on the interior of the composite and if the luminophore interacts with the membrane layer such that the luminophore is not located entirely on a surface of the membrane.

[000110] Referring next to FIG. 9, the percent increase in albedo for the combination of luminophore and membrane compared to the membrane alone is shown. The average albedo measured for Example 9 was 0.63, the integrated reflected power was 38582 W/m ² , with an input of 61260 W/m ² from the top sensor over the same period. This reflected power is was 5.27% higher than the same composite construction without phosphor measured simultaneously in Comparative Example 6 with a net gross of 1959 W/m ² extra reflected power. The albedo during this period was on average 7% higher than the albedo in Comparative Example 6 and 304% percent higher than the native grass surface of Comparative Example 5.

[000111 ] The results as tabulated in Table 2 are plotted in FIGS. 10 and 11 .

[000112] Referring to FIG. 10, the PV efficiency (Watts/g of luminophore) is plotted for examples 1-8, and comparative examples 3-5. As shown, each of the examples 1-8 have a significantly higher efficiency, indicating that they are capable of producing more energy per weight of luminophore than comparative examples.

Referring to FIG. 11, a similar conclusion is reached when looking at the plot of photosynthetic efficiency (moles of CO2 consumed/g of luminophore). As with PV efficiency, each of the examples 1-8 had improved efficiency over the comparative examples.

[000113] The invention of this application has been described above both generically and with regard to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments without departing from the scope of the disclosure. Thus, it is intended that the embodiments cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.