Window with sealant containing quantum dots

Abstract

An article comprising: (a) a glazing having opposing major surfaces and an edge extending around the major surfaces; (b) a window frame residing around at least a portion of the edge of the glazing; and (c) a sealant in light transmissive contact with an edge of the glazing; wherein the encapsulant contains quantum dots.

Description

Technical Field

[0001] The present invention relates to glazing articles comprising an encapsulant containing quantum dots.

[0002] introduction

[0003] Solar energy is a source of sustainable, "clean" energy, and its interest and application continue to grow. Harvesting solar energy typically requires positioning solar cells so that sunlight shines on those cells, which then convert the light into electricity. Positioning solar cells on building rooftops or in open fields is a common practice for solar energy harvesting to optimize their exposure to sunlight.

[0004] Collecting solar energy becomes more challenging when there are obstacles to sunlight access. For example, buildings in urban environments, such as large cities, often have other buildings blocking sunlight access. Similarly, forested areas have trees blocking sunlight access, making solar energy collection difficult for homes and buildings in forested areas. If there were a way to gather the sunlight that does reach buildings, it would help collect solar energy, particularly in environments such as urban environments and forested areas. Even better would be to direct this gathered sunlight onto solar cells. However, even more ideal would be if such methods could direct and focus sunlight onto solar cells at those wavelengths that solar cells most efficiently convert into electrical energy.

[0005] Luminescent solar concentrators are one technology developed for such applications. See, for example, Moraitis et al., Opt. Mater. 2018, 84, 636-645 for an example of a review of this technology. However, in window applications, luminescent solar concentrator technology still has room for improvement. Summary of the Invention

[0006] The present invention provides a solution to the problem of providing improvements to luminescent solar concentrator technology as it is applied to window applications.

[0007] The present invention is the result of the discovery that quantum dots can reside in the sealant of a window product. The quantum dots in the sealant of the window product can absorb light and convert that light into a wavelength that can be used by a solar cell to convert the light into electrical energy. Advantageously, the quantum dots in the sealant of the window do not reside in the viewing plane of the window and therefore do not affect viewing through the window. One disadvantage of introducing quantum dots into a window is that the quantum dots tend to affect visibility through the window. Placing the quantum dots in the sealant around the window glass places the quantum dots outside the viewing plane of the window and thereby avoids affecting viewing through the window. However, the quantum dots in the sealant can still absorb the light and convert it into electrical energy. Specifically, advantageously, the quantum dots in the sealant can convert light that would otherwise be lost by escaping the window glass through the edge of the window glass. Furthermore, the quantum dots in the window sealant can be used in combination with quantum dots in other locations of the window structure, including the viewing plane, to increase the amount of light incident on the window that can be converted into electrical energy.

[0008] In a first aspect, the present invention is an article comprising: (a) a window pane having opposing major surfaces and an edge extending around the major surfaces; (b) a window frame residing around at least a portion of the edge of the window pane; and (c) a sealant in light-transmissive contact with the edge of the window pane; wherein the sealant comprises quantum dots.

[0009] The articles of the present invention are useful as windows in structures that convert incident light into electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 (a) presents a front view of an article of the present invention, looking toward the major surface of the window pane of the article.

[0011] Figure 1 (b) shows the inspection along the inspection line A Figure 1 (a) is a side view of an embodiment of the article with a portion of the window frame 20 cut away.

[0012] Figure 1 (c) shows a view of a reflective material along inspection line A. Figure 1 (a) is a side view of an embodiment of the article with a portion of the window frame 20 cut away. DETAILED DESCRIPTION

[0013] Products identified by their trade names refer to compositions available under those trade names at the priority date of this document.

[0014] "A plurality of" means two or more. "And / or" means "and, or as an alternative." Unless otherwise indicated, all ranges are inclusive.

[0015] "Cx to Cy", "C x -C y ”, “C x-y ” are used interchangeably and refer to compositions having a number of carbon atoms in the range of x to y.

[0016] "Silicon nanoparticles" refers to silicon-based particles having an average particle size of less than 1 micron, typically 100 nanometers (nm) or less, and an average particle size of 1 nm or greater. Dynamic light scattering or transmission electron microscopy image analysis are common methods for determining the average particle size of silicon nanoparticles. Silicon nanoparticles include silicon quantum dots.

[0017] "Silicon-based" refers to compositions that contain silicon. Silicon-based materials typically contain 40 percent (%) or more, and may contain 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or even 100% silicon atoms, or a combination of silicon atoms and oxygen atoms, based on all atoms in the material.

[0018] "Quantum dots" refer to nanoscale particles that transport electrons and, when illuminated with photons with energies above the band gap of the quantum dot material, emit light of various wavelengths depending on the properties of the particle.

[0019] "Silicon quantum dots" ("SiQDs") refer to silicon nanoparticles that have a crystalline silicon structure and photoluminesce when exposed to light. Typically, the average particle size of SiQDs is in the range of 1 to 10 nanometers, preferably 1 to 6 nanometers, and more preferably 1 to 5 nanometers. Silicon quantum dots are characterized by luminescence when exposed to light with a wavelength in the range of 300 to 477 nanometers, corresponding to blue and ultraviolet light.

[0020] Unless specifically stated otherwise in the context of use, "quantum dot" as used herein refers to any type of quantum dot including SiQD.

[0021] "Solar cell" is a term interchangeable with photovoltaic cell and refers to an electronic device that converts light energy into electrical energy through a physical and chemical phenomenon known as the photovoltaic effect.

[0022] "Window glass" refers to the portion of a window that blocks wind and environmental elements (such as rain, dust, and vermin) from penetrating the window, while generally allowing light to penetrate the window. Window glass comprises at least one sheet of glazing material. Advantageously, the window glass is made from one or more sheets of glass.

[0023] "Major surface" means the surface having the highest flat surface area of ​​any surface of an article and the surface opposite that surface (if such an opposite surface exists). "Flat surface area" means the area of ​​a surface projected onto a plane to exclude pores, pits, valleys, or other contours of the surface from consideration. The "edge" of an article having opposing major surfaces means the surface that separates the opposing major surfaces and extends around the perimeter of the major surfaces.

[0024] "Light transmissive contact" refers to direct or indirect contact between two or more elements, where the contact allows light to be transmitted from one element to the other.

[0025] As used herein, "vacuum" refers to an atmosphere in which the surrounding pressure is lower than atmospheric pressure, as described herein. For example, a window having a vacuum between two window panes is a window in which the pressure between the two window panes is lower than the pressure of the atmospheric environment surrounding the window. Typically, a vacuum has a pressure lower than 101 kilopascals (kPa), and can be 50 kPa or less, 20 kPa or less, 10 kPa or less, 5 kPa or less, 1 kPa or less, or even 0.1 kPa or less.

[0026] The present invention is an article comprising: (a) a window pane having opposing major surfaces and an edge extending around the major surfaces; (b) a window frame residing around at least a portion of the edge of the window pane; and (c) a sealant positioned between the window pane and the window frame; wherein the sealant comprises SiQDs.

[0027] window glass

[0028] The article of the present invention may comprise a single glazing or a plurality of glazings, each having opposing major surfaces and an edge extending around its major surface. Within the broadest scope of the invention, there is no restriction as to the glazing material, although it advantageously allows visible light to be transmitted therethrough. When a plurality of glazings are present, the glazings may be of the same material or may be of different materials. Examples of suitable glazing materials include glazing materials comprising glass, polymers (such as organic polymers) or a combination of glass and polymers. Glass includes silicate glasses, such as soda-lime-silica glasses, borosilicate glasses. Polymers suitable for use as glazing include organic polymers, such as polymethyl methacrylate (PMMA) and polycarbonates.

[0029] Window glazing can include quantum dots on and / or in the glazing. For example, a polymer glazing can be a polymer film with quantum dots dispersed within the film or coated on the surface of the film. Gallagher et al., Sol. Energy 2007, 81, 813-821, describe quantum dot solar concentrators suitable for use as window glazing, which have quantum dots dispersed in a polyurethane or PMMA sheet. Window glazing can have quantum dots attached to the surface of the window glazing directly or as a polymer film or coating containing quantum dots attached to the surface of the window glazing.

[0030] The articles of the present invention may comprise laminated glass as one or more window panes. The laminated glass comprises sheets of glass having major surfaces laminated to each other, with a polymer film between the sheets of glass. The laminated glass may be in the form of "safety glass". Common polymer films between the sheets of glass include ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) and ionomers. The laminated glass may contain quantum dots. For example, the polymer film between the sheets of glass of the laminated glass may contain quantum dots. For example, US2017 / 0341346 discloses a laminated glass luminescent concentrator having a specific type of quantum dots in the polymer film between the sheets of glass of the laminated glass, and such laminated glass is suitable for use as a window pane in the present invention. Specifically, the present invention may include a laminated glass having SiQDs in or on the polymer film between the sheets of glass of the laminated glass. SiQDs are particularly ideal in such applications due to their temperature stability, which allows the SiQDs to be included in processes using lamination at temperatures higher than temperatures at which other quantum dots would degrade.

[0031] The article of the present invention may be an insulating window comprising two or more window panes separated from each other to define a volume between the two or more window panes, the volume being sealed and having a vacuum or insulating gas in the volume between the two or more window panes. The vacuum or insulating gas suppresses thermal conductivity through the window panes. Examples of suitable insulating gases include any one or combination of inert gases, such as those selected from the group consisting of argon, krypton and xenon. The insulating window may include quantum dots, thereby including SiQDs. The quantum dots may reside within one or more window panes of the insulating window. The quantum dots may reside on the surface of one or more window panes of the insulating window, preferably on a surface in contact with a volume under vacuum or containing an insulating gas. The quantum dots may reside directly on the surface of the window pane, or in a polymer film or coating on the surface of the window pane.

[0032] The articles of the present invention may comprise a plurality of panes separated by muntins so as to have a grid or lattice appearance.

[0033] window frame

[0034] The article of the present invention comprises a window frame. The window frame holds one or more window panes of the article in place. The window frame resides around at least a portion of the edge of the window pane of the article. If the article comprises multiple window panes, the window frame advantageously extends around at least a portion of the edge of all the window panes. Advantageously, the window frame extends all the way around the edge of the window panes. The window frame typically includes side rails, which are vertical portions of the window frame and form the sides of the window frame, and a top rail and a bottom rail, which respectively form the top and bottom of the window frame.

[0035] In the broadest scope of the present invention, there is no limitation on the composition of the window form. Common materials that can be used for window frames include wood, plastic, metal or a combination thereof.

[0036] sealant

[0037] The articles of the present invention comprise a sealant in light-transmissive contact with the edge of one or more window panes. The sealant can be used to provide an airtight contact between the window pane and a window frame or other element adjacent to the window pane. Typically, the articles of the present invention include a window frame extending all the way around the window pane (or combination of window panes), wherein the sealant resides between the window pane and the window frame and forms a seal between the window pane and the window frame. The sealant can reside only between a portion of the window pane and a portion of the window frame, or can extend all the way around the window pane and the window frame.

[0038] In the broadest sense of the present invention, the sealant can be any sealant that can be used to seal windows and includes window tape, rubber window seals, and caulks. The sealant can include silicone caulks, polyurethane caulks, acrylic latex caulks, and butyl rubber caulks. Of particular interest are silicone room temperature vulcanizing (RTV) sealant materials.

[0039] The sealant includes quantum dots. The quantum dots are advantageously dispersed within the sealant. Preferably, the quantum dots are dispersed within the sealant and the sealant transmits (at least partially) UV and / or visible light. The quantum dots may be SiQDs, which provide greater thermal stability than many other quantum dots. Additionally, SiQDs tend to be particularly compatible with silicone caulk compositions, one of the most desirable sealants for windows. Advantageously, the sealant is a silicone caulk having SiQDs dispersed therein.

[0040] The concentration of quantum dots in the sealant is not critical to the broadest scope of the invention. The purpose of having quantum dots in the sealant is to capture UV and / or blue light reflected in and out of the edges of the window pane and convert it into light that can be used by the solar cell to generate electricity. Therefore, a higher concentration of quantum dots in the sealant is desirable. Typically, the concentration of quantum dots in the sealant is 0.1 weight percent (wt%) or greater, preferably 1 wt% or greater, 5 wt% or greater, or even 10 wt% or greater, while it is often 30 wt% or less, 20 wt% or less, 15 wt% or less, and can be 10 wt% or less.

[0041] The quantum dots can be physically blended into the sealant to obtain the sealant of the present invention. The quantum dots can be dispersed in a liquid carrier and blended with the sealant to facilitate mixing. Any mixing method is suitable, including, for example, continuous methods such as extrusion mixing, and batch or semi-batch methods such as blender mixing.

[0042] solar cells

[0043] Advantageously, the article of the present invention comprises at least one, and may comprise more than one, solar cell in light-transmissive contact with the edge of the window pane and / or the quantum dot-containing sealant.

[0044] When the solar cell is in optically transmissive contact with the edge of the window glass, the sealant containing quantum dots is also in optically transmissive contact with a portion of the edge of the window glass. The solar cell collects light transmitted by the window glass to the edge of the window glass and converts the light into electricity. The quantum dots in the sealant advantageously emit light of a wavelength that can be converted into electricity by the solar cell. In such a configuration, UV or blue light that leaves the edge of the window glass and strikes the sealant containing quantum dots can be absorbed by the quantum dots in the sealant. The quantum dots can then emit light back into the edge of the window glass and travel through the window glass to the solar cell in optically transmissive contact with the edge of the window glass. The light from the quantum dots can then be converted into electricity. Advantageously, the sealant, with or without quantum dots, provides a seal between the window glass and the window frame around the solar cell in optically transmissive contact with the window glass.

[0045] When the solar cell is in light-transmitting contact with the encapsulant, light emitted by the quantum dots in the encapsulant can be transmitted directly to the solar cell for conversion into electricity.

[0046] Examples of suitable solar cells include those made using, for example, single crystal silicon (m-Si), multicrystalline silicon, amorphous silicon, copper indium gallium selenide (CIGS), and cadmium telluride (CdTe) materials.

[0047] reflective materials

[0048] The articles of the present invention may include a reflective material in light-transmissive contact with a portion of one or more edges of the window pane. The reflective material may be desirable to reflect light that would otherwise be lost through the edge of the window pane back into the window pane. Lewo et al., J. Appl. Phys., 2013, 113, 214510 describe the use of reflective panel edges to reduce the loss of photons from luminescent solar concentrators. Such applications of reflective materials can be applied to the present invention. The reflective material, if present, is in light-transmissive contact with a portion of the edge of at least one window pane of the article, and the sealant is also in light-transmissive contact with the window pane. The article may include a reflective material, a sealant, and at least one solar cell, all of which are in light-transmissive contact with the edge of the window pane.

[0049] Examples of suitable reflective materials include metals such as aluminum, silver, and chromium, and compounds such as zinc sulfide and titanium dioxide.

[0050] Figure 1 An exemplary article of the present invention is shown having a window pane 10 having a major surface 15 and a window frame 20 extending around the perimeter of the window pane 10 . Figure 1 (a) shows an exemplary article facing the major surface 15 of the glazing 10 . Figure 1 (b) and Figure 1 (c) shows the inspection along the inspection line A Figure 1 Side views of two embodiments of the article in (a). Figure 1 (b) shows an embodiment with sealant 30 on the edge of the window pane 10 and also with solar cells 40 on the edge of the window pane 10 . Figure 1 (c) shows an embodiment having a sealant 30, solar cells 40 and reflective material 50 on the edge of the window glass 10. The sealant 30 has quantum dots (not shown) dispersed therein.

Claims

1. A product comprising: a window pane, the window pane having opposing major surfaces and edges extending around the major surfaces; b. a window frame residing around at least a portion of the edge of the window pane; and c. a sealant in light-transmitting contact with the edge of the window pane; wherein the encapsulant comprises quantum dots.

2. The article of claim 1 , wherein the article comprises a plurality of window panes, each of the plurality of window panes having opposing major surfaces and edges extending around the major surfaces, and wherein the window frame resides around at least a portion of the edges of two window panes, and wherein the sealant is located between one or both window panes and the window frame.

3. The article of claim 1 or claim 2, wherein the article further comprises a solar cell in light-transmissive contact with the sealant and / or at least one edge of at least one window pane.

4. An article according to any preceding claim, wherein the article comprises a reflective material in light-transmissive contact with a portion of one or more edges of the window pane.

5. An article according to any preceding claim, wherein the quantum dots are: (i) dispersed in at least one glazing; and / or (ii) dispersed on and / or in a film or coating on a major surface of the glazing.

6. The article of any preceding claim, wherein the quantum dots are silicon quantum dots.

7. The article of any preceding claim, wherein the encapsulant is a silicone encapsulant having silicon quantum dots dispersed therein.

8. An article according to any preceding claim, wherein the article comprises a laminated glazing having glass sheets laminated together with a polymer film between the glass sheets, and the laminated glazing optionally comprises quantum dots in the polymer film.

9. An article according to any preceding claim, wherein the article comprises two or more window panes, the two or more window panes being separated from each other to define a volume between the two or more window panes, the volume being sealed and having a vacuum or insulating gas in the volume between the two or more window panes, wherein the article optionally further comprises quantum dots in one or more of the window panes and / or on the surface of one or more of the window panes.

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