Composition and method for manufacturing a glazing unit using the same

Abstract

The disclosure relates to a composition for application on a substrate (2) of a glazing unit (1) at least partially consisting of a transparent or translucent material to form a photonically active region (7) of glazing unit (1). The disclosure further relates to a method for manufacturing a glazing unit (1), comprising the steps of applying at least one composition onto the surface (6) of the substrate (2) to obtain, after removal of the solvent, a photonically active region (7) configured to reflect a first partial spectrum of incident light and enabling transmission of a second partial spectrum of incident light.

Description

[0001] Composition and method for manufacturing a glazing unit using the same

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure generally relates to the field of building materials and renewable energy technologies, and more particularly to techniques for manufacturing colored glazing units, specifically photovoltaic panels, using a solventbased composition.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Solar technology has undergone significant changes in recent years, not just in terms of its efficiency but also in terms of its appearance, especially concerning integration of photovoltaic systems into architectural design. Colored photovoltaic modules see high demand, as they allow solar technology to blend seamlessly with building design. However, a few challenges, such as shading losses, limited color saturation, and angular instability, have made it difficult for market solutions like screen printing and interference coatings to achieve this seamlessly.

[0006] Some attempts have been made to tackle these challenges, which are briefly discussed hereinafter.

[0007] EP0632507A2 published in 1995 in the name of Optical Coating Laboratory Inc. relates to a solar cell cover comprising a substrate that transmits the spectral region to which the solar cell responds and a multilayer infrared-reflecting coating which incorporates means for suppressing low order reflections. The multilayer coating reflects one or both substrate surfaces. The multilayer coating reflects spectral bands which are adjacent to the short- and long- wavelength limits of the spectral response of the cell. The upper limit wavelength of the short-wavelength reflection band and the lower wavelength limit of the long-wavelength reflection band are independent and may be separately specified.

[0008] US2011299167 published in 2011 in the name of General Atomics relates to a reflective coating, that has a base layer provided with a reflective surface for reflecting electromagnetic radiation, such as visible and solar near-infrared light. The reflective coating also has a dielectric layer formed on the reflective surface, and an absorber layer. The absorber layer is formed on the dielectric layer that is formed on the base layer. The reflective coating has an average reflectance greater than about 60 percent for wavelengths of electromagnetic radiation in the range of 800 to 2500 nm that is irradiated upon the reflective coating. Additionally, the reflective coating has an average reflectance for wavelengths of electromagnetic radiation in the range of 400 to 700 nm irradiated upon the reflecting coating that is less than the average reflectance of the reflective coating from 800 to 2500 nm.

[0009] W02017090056A1 published in 2017 in the name of Indian Inst Of Technology Bombay relates to solar module including an element positioned on a solar cell. One or more reflective colored coating layer(s) is deposited on the element or the solar cell. The reflective colored coating layer can selectively reflect a desired wavelength of light and can provide the required color on the solar cell or the solar module without altering the structure or manufacturing process of the solar cell. US2018122973 published in 2018 in the name of Tesla Inc. relates to a solar panel including a backsheet layer, a bottom encapsulant layer adjacent the back- sheet layer, a plurality of photovoltaic cells adjacent the bottom encapsulant layer, a top encapsulant layer adjacent the plurality of photovoltaic cells having a plurality of louvers constructed therein to block side view of the plurality of photovoltaic cells, and a top layer adjacent the top encapsulant layer.

[0010] US2017107379 published in 2019 in the name of Merck Patent GmbH relates to frits or frit mixtures with pearlescent pigments for materials, such as ceramic glazes, which are stable above 1000° C.

[0011] US2019386607 published in 2019 in the name of Fraunhofer Gesellschaft zur Fdrderung der angewandten Forschung e.V. relates to a glazing unit for producing an esthetically pleasing effect, comprising or consisting of at least one pane, said pane having a first structured surface to which a three-dimensional photonic structure is applied and the average refractive index of the photonic structure being higher than approximately 1.6 or higher than approximately 1.8 or higher than approximately 1.95. The invention also relates to the production of such a glazing unit and the use thereof.

[0012] US2021395543 published in 2020 in the name of Tecglass SL relates to ceramic inkjet inks for non-porous substrates (such as glasses and metals), by means of which the viscosity of the inks at the jetting temperature of 33-50 degrees C is 8- 20 mPa s and increases substantially by a factor of more than 5 (at more than 100 mPa s) after discharging onto the substrate. SUMMARY OF THE DISCLOSURE

[0013] The current state of the art involves the application of an interference layer to the interior surface of structured glass within a photovoltaic (PV) panel using the sputter coating method. This deliberate contruction not only provides high efficiency, with rates exceeding 90%, but also allows for the realization of saturated and vibrant colors. The technology exhibits good angular stability, maintaining color integrity even at oblique viewing angles.

[0014] Despite its advantages, the sputter coating method has several disadvantages. First, it is a complex process that is expensive to implement on a large scale. Second, the sputter coating method requires specialized equipment and trained personnel, adding further complexity and cost. Third, the process can be timeconsuming, which may impact production schedules and increase lead times.

[0015] The objective of the present disclosure is to address these limitations and unlock new possibilities for large-scale and cost-effective production of colored glazing unit and in particular of colored photovoltaic panels. By developing a more streamlined and adaptable approach to manufacturing colored glazing units, it is possible to improve efficiency, reduce costs, and increase scalability, ultimately leading to more widespread adoption of this technology in the renewable energy sector.

[0016] The present disclosure addresses the need to revolutionize the material deposition process for colored photovoltaic panels by utilizing solution-based processes, in particular inkjet printing or spray coating. This transition to a solutionbased process has the potential to open up new opportunities for large-scale and cost-effective production of colored photovoltaic panels. The disclosure offers a number of advantages, including design flexibility, vibrant color options, and cost effectiveness. This allows to refine the aesthetics of solar technology and usher in a cost-effective and scalable era for the industrial production of colored photovoltaic panels.

[0017] One aspect of the present disclosure therefore relates to a composition for application on a substrate comprised of at least partial transparent or translucent material to form a photonically active region of glazing unit, particularly a photovoltaic panel. The composition includes a solvent comprising an alcohol amounting to 10-20% of the total weight of the solvent, and photonically active nanoparticles. The alcohol preferably is isopropanol or ethanol and / or diethylene glycol. Compositions according to the disclosure preferably form the basis for inks suitable for printing. The composition facilitates simplified and efficient manufacturing methods for photovoltaic panels to create a photonically active region or layer mainly composed of the nanoparticles.

[0018] The solvent with 10-20% alcohol ensures efficient application and adhesion for the nanoparticles. The nanoparticles provide photonically active properties in the final glazing unit. This novel approach offers several technical advantages over current methods, including streamlined processing, enhanced efficiency, reduced complexity, and scalability, making it a promising candidate for large-scale, cost- effective production of colored photovoltaic panels. Photonically active region in a photovoltaic panel can be understood as a specific arrangement of materials designed to regulate transmission and reflection of incident electromagnetic radiation. Within a glazing unit the photonically active region is usually one or more layers forming as a photonic glass, photonic crystal, thin film filter, or Bragg filter that is designed to reflect and transmit certain wavelengths of electromagnetic radiation. If appropriate, the region comprises two or more alternating layers with a refractive index between about 1.5 and about 2.2 and between about 1.8 and about 2.5. The mean refractive index of the glazing unit is usually greater than about 1 .65, 1 .8, or 2 at a wavelength of 550 nm. This allows reflection of a higher harmonic in the visible spectral range, in particular the second and / or third higher harmonic. The mean refractive index can be determined as the weighted average of the refractive indices based on the volume proportions of each material in the region. This specific configuration enables efficient control over optical properties while maintaining feasibility in manufacturing processes, "photonic glass" in comparison to "photonic crystal," refers to a disordered arrangement of (monodisperse spherical) nanoparticles with short-range order due to physical contact between particles, while the latter describes periodically ordered patterns with a period of the order of the wavelength of the electromagnetic radiation.

[0019] Photonically active nanoparticles can be understood as a nanoparticles that generally manipulate electromagnetic radiation as single particle and / or when multiple such particles are arranged together (e.g. in a photonic active region as described above). Manipulation of electromagnetic radiation in this context typically refers to constructive and destructive interference of reflected incident electromagnetic radiation. In particular photonically active nanoparticles allow reflection of a higher harmonic in the visible spectral range, in particular the second and / or third higher harmonic, while minimizing the reflection of wavelengths above and below the reflection peak in the visible spectral range.

[0020] In a preferred variation the photonically active nanoparticles comprise at least three layers. In particular, a first layer having a first refractive index, a second layer having a second refractive index arranged adjacent to the first layer, wherein the first refractive index is lower than the second refractive index and a third layer having a third refractive index arranged adjacent to the second layer, wherein the third refractive index is lower than the second refractive index.

[0021] Good performance is possible, when the photonically active nanoparticles consist at least partially of a metal oxide, preferably at least one out of the following titanium dioxide (TiO2), zirconium dioxide (ZrO2), silicon nitride (Si3N4) and aluminium oxide (AI2O3) or a combination thereof.

[0022] Depending on the field of application, the nanoparticles are essentially spherical. However other shapes are also possible, such as platelets (essentially plateshaped).

[0023] Good results are possible when the nanoparticles have an average particle diameter between 50nm and 1500nm, preferably between 100nm and 800nm, more preferably between 150nm and 600nm, most preferably between 100nm and 300nm. To be suitable for inkjet printing, the nanoparticles should have a diameter of about 50 times less than a nozzle diameter of the printer nozzle. Typical printer nozzle diameters are between 50 and 100 micro meter, such as 70 micro meters. The nanoparticles preferably amount to 1 -5% of the total weight of the composition.

[0024] In some variations the composition comprises a dispersion agent amounting to 0.1 -1 % of the total weight of the composition. The dispersion agent is preferably at least one of the following: sodium dodecyl sulfate (SDS) and Octoxynol 9 (Pol- yethylenglycol-[4-(1 ,1 ,3,3-tetramethylbutyl)phenyl]-ether) or a combination thereof.

[0025] To improve dispersion of the nanoparticles in the composition, preferably a mixture of alcohol and diethylene glycol (DEG) with a ratio of 1 : 1 (in volume) is used. Here DEG acts as a co-solvent.

[0026] If appropriate the composition comprises a viscosity modifier, such that a viscosity between 10 to 100 mPa s is achieved, preferably between 10 to 40 mPa s. The resulting surface tension of the composition falls between 30 and 50 mN / m.

[0027] In preferred variations the composition comprises hydroxypropyl methyl cellulose (HPMC). In particular as a 0.01 - 3 weight percent aqueous solution, preferably around 1 - 2 weight percent. HPMC offers benefits such as biocompatibility, renewability, good surface tension and viscosity.

[0028] To ensure optimal performance the composition comprises a pH regulator agent, such that a pH value between 7 and 8.5 is achieved. In some variations, the composition comprises at least one binder and / or at least one polymer agents, which amount to 1 -10 % of the total weight of the composition to form a paste. This paste can be applied to the substrate of a glazing unit instead of inkjet printing or spray coating by a screen printing process. To ensure that all the components of the paste are mixed uniformly, including nanoparticles, binders, polymer agents, and solvent, it must be thoroughly stirred.

[0029] In order to utilize the composition according to the disclosure as an ink suitable for inkjet printing, the components are combined and stirred thoroughly to achieve a homogeneous solution. To disperse any potential agglomerates, the solution is preferably sonicated. Additional components such as water may be added.

[0030] Compared to sputter coating the mentioned application processes provide the advantage that the color appearance of the glazing unit can be applied to form patterns, such as periodic patterns or even logos etc. in color.

[0031] Another aspect of the disclosure relates to a method for manufacturing a glazing unit. The method comprises the steps of providing a substrate at least partially consisting of a transparent or translucent material having a surface and applying at least one composition according to the disclosure onto the surface of the substrate to obtain, after removal of the solvent, a photonically active region on the substrate, configured to reflect a first partial spectrum of incident light and enabling transmission of a second partial spectrum of incident light. The term light typically refers to electromagnetic radiation in the visible spectral range. Good results can be achieved, when applying at least one composition comprises applying a first, a second and a third composition according to the disclosure onto the substrate. In particular the method preferably comprises applying a first composition according to the disclosure to form a first layer having a first refractive index onto the substrate, applying a second composition according to the disclosure to form a second layer having a second refractive index onto the first layer, wherein the first refractive index is lower than the second refractive index, and applying a third composition according to the disclosure to form a third layer having a third refractive index onto the second layer, wherein the third refractive index is lower than the second refractive index. This results in a photonically active stack of at least three layers, however more layers are possible and in some cases even preferred. The layers of the photonically active stack typically have layers of periodically alternating refractive indices. Typically the first and the third refractive indices are essentially identical. Correspondingly the first and the third layer preferably have essentially the same thickness.

[0032] In preferred variations, applying at least one composition utilizes at least one of the following: spray coating, inkjet printing, roll-to-rol I coating, dip-coating, screen printing and aerosol jet printing, or a combination thereof. Using these cost efficient application processes is one of the keys to a scalable production of glazing unit having a long lasting color appearance with high angular stability.

[0033] After deposition, the applied layers are usually dried for 5 to 30 minutes, preferably around 15 minutes, on a heating plate at a temperature between 50 and 100 °C, preferably at around 80°C, to remove the solvent. Another aspect of the disclosure relates to a method for manufacturing of photonically active nanoparticles, comprising the steps of providing a substrate having applied to a surface a sacrificial-release layer and applying a photonically active stack of layers onto the sacrificial-release layer. The method further comprises detaching or releasing the sacrificial-release layer, laden with the photonically active stack of layers from the solid substrate and subjecting the detached sacrificial-release layer to a controlled crushing process to transform the photonically active stack of layers into nanoparticles. Preferably the photonically active stack of layers comprises at least a first layer having a first refractive index, a second layer having a second refractive index arranged adjacent to the first layer, wherein the first refractive index is lower than the second refractive index and a third layer having a third refractive index arranged adjacent to the second layer, wherein the third refractive index is lower than the second refractive index. Four or more layers are possible and in some cases even preferred.

[0034] In some variations at least one layer of the photonically active stack is applied by a sputtering process, however other processes such as spray coating, inkjet printing, roll-to-roll coating, dip-coating, screen printing and aerosol jet printing, or a combination thereof are possible as well.

[0035] In some variations the controlled crushing process involves mechanical procedures, comprising at least one of the following ball milling, attrition or jet milling, cryogenic grinding, and ion beam milling.

[0036] In some variations the controlled crushing process involves laser ablation, wherein a laser beam induces material ablation to create nanoparticles. In some variations the controlled crushing process involves ultra-sonication, utilizing high-frequency sound waves in a liquid medium to generate mechanical forces that break down the sacrificial-release layer into nanoparticles.

[0037] In some preferred variations the sacrificial-release layer comprises a water-solu- ble polymer, facilitating easy dissolution thereof.

[0038] It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing:

[0041] Fig. 1 a first variation of a glazing unit 1 according to the disclosure in a perspective view; Fig. 2 an intermediate product of the method to manufacture photonically active nanoparticles according to the disclosure; and

[0042] Fig. 3 a photonically active nanoparticle 8 according to the disclosure in a cross-sectional view.

[0043] DESCRIPTION OF THE EMBODIMENTS

[0044] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0045] Figure 1 shows a first variation of a glazing unit 1 according to the disclosure in a perspective view. The shown glazing unit 1 is a photovoltaic panel and comprises several layers. These are, from top to bottom, the substrate (layer) 2 having applied to its surface 6 a first layer 3 having a first refractive index. A second layer 4 having a second refractive index is arranged adjacent to the first layer 3, wherein the first refractive index is lower than the second refractive index. A third layer 5 having a third refractive index is arranged adjacent to the second layer 4, wherein the third refractive index is lower than the second refractive index. Typically the first and the third refractive indices are essentially identical. Correspondingly the first and the third layer 3, 5 have essentially the same thickness. At the bottom a photovoltaic layer 10 is arranged, in the shown first variation, separated from the photonically active region 7 by a passivation layer 9. The photovoltaic layer 10 comprises at least one photovoltaic cell for converting the transmitted electromagnetic radiation into electricity. The photonically active region 7 is formed by the three layers 3 to 5 of alternating refractive indices.

[0046] In Figure 2 an intermediate product of the method to manufacture photonically active nanoparticles according to the disclosure is shown and in Figure 3 a photonically active nanoparticle 8 according to the disclosure. The intermediate product of Figure 2 can be processed into the nanoparticle 8 of Figure 3.

[0047] The intermediate product of Figure 2 comprises an phonically active region 7 formed by a stack of three layers 3 to 5. These three layers 3 to 5 are similar to the ones of the glazing unit 1 of Figure 1. The photonically active stack of layers 3 to 5 is arranged between two passivation layers 9 encapsulating the stack. The encapsulated stack is arranged on a substrate 2 separated therefrom by a sacrificial-release layer 11 . During manufacturing of nanoparticles from the intermediate product, the encapsulated photonically active stack of layers 3 to 5 is detached from the substrate 2 by dissolution of the sacrificial-release layer 11 .

[0048] Figure 3 shows an essentially spherical nanoparticle 8. This nanoparticle comprises a photonically active stack of layers 3 to 5 arranged between passivation layers 9 encapsulating the stack. The layers of the stack are, in this shown variation, circular, wherein in a single passivation layer 9 encapsulates the nanopar- tide. The shown single nanoparticle 8 acts as a photonically active region 7 according to the disclosure, however for visible (larger scale) effects, a multiplicity of such nanoparticles 8 needs to be applied to a substrate 2 of a glazing unit 1 .

[0049] Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the scope of the disclosure.

[0050] LIST OF DESIGNATIONS

[0051] 1 Glazing unit

[0052] 2 Substrate

[0053] 3 First layer 4 Second layer

[0054] 5 Third layer

[0055] 6 Surface (substrate)

[0056] 7 Photonically active region

[0057] 8 Nanoparticle 9 Passivation layer

[0058] 10 Photovoltaic layer

[0059] 11 Sacrificial-release layer

Claims

PATENT CLAIMS1. Composition for application on a substrate (2) of a glazing unit (1 ) at least partially consisting of a transparent or translucent material to form a photon- ically active region (7) of glazing unit (1 ), in particular of a photovoltaic panel, the composition comprising a. a solvent comprising an alcohol, preferably isopropanol or ethanol and / or diethylene glycol, amounting to 10-20% of the total weight of the solvent; and b. photonically active nanoparticles (8).

2. Composition according to claim 1 , wherein the photonically active nanoparticles (8) comprise a. a first layer (3) having a first refractive index; b. a second layer (4) having a second refractive index arranged adjacent to the first layer (3), wherein the first refractive index is lower than the second refractive index; and c. a third layer (5) having a third refractive index arranged adjacent to the second layer (4), wherein the third refractive index is lower than the second refractive index.

3. Composition according to at least one of the preceding claims, wherein the photonically active nanoparticles (8) consist at least partially of metal oxide,preferably at least one out of the following TiO2, ZrO2, Si3N4 and AI2O3 or a combination thereof.

4. Composition according to at least one of the preceding claims, wherein the nanoparticles are essentially spherical.

5. Composition according to at least one of the preceding claims, wherein the nanoparticles have an average particle diameter between 50nm am 1500nm, preferably between 100nm and 800nm, more preferably between 150nm and 600nm.

6. Composition according to at least one of the preceding claims, wherein the nanoparticles amount to 1 -5% of the total weight.

7. Composition according to at least one of the preceding claims, wherein a dispersion agent amounts to 0.1 -1 % of the total weight.

8. Composition according to at least one of the preceding claims, wherein the composition comprises a viscosity modifier, such that a viscosity between 10 to 40 mPa s is achieved.

9. Composition according to at least one of the preceding claims, wherein the composition comprises a pH regulator agent, such that a pH value between7 and 8.5 is achieved.

10. Composition according to at least one of the preceding claims, wherein the composition comprises at least one binder and / or at least one polymer agents, which amount to 1 -10 % of the total weight to form a paste.11 . Method for manufacturing a glazing unit (1 ), comprising the steps of a. providing a substrate (2) at least partially consisting of a transparent or translucent material having a surface (6); b. applying at least one composition according at least one of claims 1 to 10 onto the surface (6) of the substrate (2) to obtain, after removal of the solvent, a photonically active region (7) configured to reflect a first partial spectrum of incident light and enabling transmission of a second partial spectrum of incident light.

12. Method according to claim 11 , wherein applying at least one composition comprises: a. applying a first composition according to at least one of claims 1 to 10 to form a first layer (3) having a first refractive index onto the substrate (2); b. applying a second composition according to at least one of claims 1 to 10 to form a second layer (4) having a second refractive index onto the first layer (3), wherein the first refractive index is lower than the second refractive index; andc. applying a third composition according to at least one of claims 1 to 10 to form a third layer (5) having a third refractive index onto the second layer (4), wherein the third refractive index is lower than the second refractive index.

13. Method according to at least one of the preceding claims 11 to 12, wherein applying at least one composition utilizes at least one of the following: spray coating, inkjet printing, roll-to-roll coating, dip-coating, screen printing and aerosol Jet Printing, or a combination thereof.

14. Method for manufacturing of photonically active nanoparticles, comprising the steps of: a. providing a substrate (2) having applied to a surface (6) a sacrificial- release layer (11 ); b. applying photonically active stack of layers (3, 4, 5) onto the sacrificial-release layer (11 ), wherein the photonically active stack of lay- ers (3, 4, 5) comprises at least i. a first layer (3) having a first refractive index; ii. a second layer (4) having a second refractive index arranged adjacent to the first layer (3), wherein the first refractive index is lower than the second refractive index; andiii. a third layer (5) having a third refractive index arranged adjacent to the second layer (4), wherein the third refractive index is lower than the second refractive index. c. detaching or releasing the sacrificial-release layer (11 ), laden with the photonically active stack of layers (3, 4, 5), from the solid substrate; d. subjecting the detached sacrificial-release layer (11 ) to a controlled crushing process to transform the photonically active stack of layers (3, 4, 5) into nanoparticles (8).

15. The method for manufacturing of nanoparticles according to claim 14, wherein the at least one layer (3, 4, 5) of the photonically active stack is applied by a sputtering process.

16. The method for manufacturing of nanoparticles according to claim 14 or 15, wherein the controlled crushing process involves mechanical procedures, comprising at least one of the following ball milling, attrition or jet milling, cryogenic grinding, and ion beam milling.

17. The method for manufacturing of nanoparticles according to claim 14 or 15, wherein the controlled crushing process involves laser ablation, wherein a laser beam induces material ablation to create nanoparticles.

18. The method for manufacturing of nanoparticles according to claim 14 or 15, wherein the controlled crushing process involves ultra-sonication, utilizinghigh-frequency sound waves in a liquid medium to generate mechanical forces that break down the sacrificial-release layer into nanoparticles.

19. The method for manufacturing of nanoparticles according to claim 14 or 15, wherein the sacrificial-release layer comprises a water-soluble polymer, fa- cilitating easy dissolution during subsequent processing steps.

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