[go: up one dir, main page]

WO2012162446A1 - Light scattering articles by abrasion and etch - Google Patents

Light scattering articles by abrasion and etch Download PDF

Info

Publication number
WO2012162446A1
WO2012162446A1 PCT/US2012/039233 US2012039233W WO2012162446A1 WO 2012162446 A1 WO2012162446 A1 WO 2012162446A1 US 2012039233 W US2012039233 W US 2012039233W WO 2012162446 A1 WO2012162446 A1 WO 2012162446A1
Authority
WO
WIPO (PCT)
Prior art keywords
glass substrate
etching
spraying
microns
textured
Prior art date
Application number
PCT/US2012/039233
Other languages
French (fr)
Inventor
Antoine Bisson
Sasha Marjanovic
Original Assignee
Corning Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Corning Incorporated filed Critical Corning Incorporated
Publication of WO2012162446A1 publication Critical patent/WO2012162446A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
    • B24C7/0007—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts the abrasive material being fed in a liquid carrier
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/06—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for producing matt surfaces, e.g. on plastic materials, on glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C15/00—Surface treatment of glass, not in the form of fibres or filaments, by etching
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C19/00—Surface treatment of glass, not in the form of fibres or filaments, by mechanical means
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • C09K3/14—Anti-slip materials; Abrasives
    • C09K3/1454—Abrasive powders, suspensions and pastes for polishing
    • C09K3/1463—Aqueous liquid suspensions
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/70—Surface textures, e.g. pyramid structures
    • H10F77/707—Surface textures, e.g. pyramid structures of the substrates or of layers on substrates, e.g. textured ITO layer on a glass substrate
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • Embodiments relate generally to light scattering articles and more particularly to light scattering inorganic articles having textured surfaces and abrasive methods of making the textured surfaces useful for, for example,
  • Thin film amorphous/microcrystalline silicon (Si-tandem) type photovoltaic cells are based on the use of a glass sheet onto which an assembly of thin films (TCO, amorphous silicon, crystalline silicon and anti reflective coating) are
  • the texture of the TCO can have a direct and/or indirect impact on the overall cell quantum efficiency (Q.E.) yield.
  • the glass superstrate when textured, can be used to orient the texture of the TCO.
  • WO 2009/026648 Al (CSG Solar AG) describes abrasion and etch texturing of glass where the initial abrasion is done by sandblasting. It seems that the preferred method is dry sandblasting, and that wet sandblasting is added as a possible alternative. Orbital lapping is also mentioned as a possible texturing technique.
  • Light scattering articles and methods of making the light scattering articles address one or more of the above-mentioned disadvantages of conventional light scattering articles and/or methods and may provide one or more of the following advantages: simplicity and potential high throughput in manufacturing, flexibility in the final properties such as haze and diffusion, and the potential to texture only parts of the initial substrate by masking select areas of the glass substrate.
  • One embodiment is a method comprising providing a glass substrate having a surface, spraying the surface with a slurry comprising abrasive particles and water to form an abraded surface, and etching the abraded surface to form a textured glass substrate.
  • Another embodiment is a photovoltaic device comprising a light scattering article comprising a glass substrate having a textured surface, wherein the surface comprises smooth craters having an average width of from 1 to 10 microns; a conductive material adjacent to the particles; and an active photovoltaic medium adjacent to the conductive material.
  • Figure 1 is a schematic diagram of features of a Si- tandem PV solar cell, according to one embodiment.
  • Figure 2 is an optical photo of the sandblasting step in an exemplary method.
  • Figure 3 is a flow chart of an exemplary method.
  • Figures 4A and 4B are scanning electron microscope (SEM) images of an exemplary abraded surface obtained after the sandblasting step.
  • Figures 5A and 5B are SEM images of the surface obtained after sandblasting and etching steps, according to one embodiment .
  • Figure 6 is a graph showing diffuse transmittance after exemplary sandblasting and etching for four typical textures: ultra-high, high, medium and low haze textures (from top to bottom) .
  • Figure 7 is a graph showing angular scattering for an exemplary medium haze sandblasted and etched glass substrate
  • Figure 8 is a graph showing angular scattering for an exemplary high haze sandblasted and etched glass substrate.
  • the term "substrate” can be used to describe either a substrate or a superstrate depending on the configuration of the photovoltaic cell.
  • the substrate is a superstrate, if when assembled into a
  • the photovoltaic cell it is on the light incident side of a photovoltaic cell .
  • the superstrate can provide protection for the photovoltaic materials from impact and environmental degradation while allowing transmission of the appropriate wavelengths of the solar spectrum. Further, multiple
  • photovoltaic cells can be arranged into a photovoltaic module.
  • Adjacent can be defined as being in close proximity. Adjacent structures may or may not be in physical contact with each other. Adjacent structures can have other layers and/or structures disposed between them.
  • One embodiment, as shown by the schematic diagram in Figure 1, are features 100 of a photovoltaic device, for example, a Si-tandem PV solar cell comprising a light
  • the scattering article comprising a glass substrate 10 having a textured surface 11, wherein the surface comprises smooth craters having an average width of from 1 to 15 microns; a conductive material 12 adjacent to the surface; and an active photovoltaic medium adjacent to the conductive material.
  • the active photovoltaic medium is a Si-tandem
  • the smooth craters can be random in size and some craters can be smaller or larger than 1 to 15 microns.
  • the conductive material is a transparent conductive film.
  • the transparent conductive film for example, a transparent conductive oxide (TCO) can comprise a textured surface.
  • the texture of the TCO can be conformal to the texture of the textured glass substrate.
  • the active photovoltaic medium can be in physical contact with the transparent conductive film.
  • the device further comprises a counter electrode 18 in physical contact with the active photovoltaic medium and located on an opposite surface of the active photovoltaic medium as the conductive material.
  • the device can further comprise a back reflector 20 adjacent to the counter electrode.
  • the texturing from the textured glass substrate can be conformal throughout all of the layers.
  • the white arrows show light scattering through the textured layers of the photovoltaic device.
  • the TCO in one embodiment, is from greater than 0 to 2 microns in thickness, for example, 0.5 microns to 1.5 microns, for example, 0.5 microns to 1 micron in thickness.
  • the amorphous silicon in one embodiment, is greater than 0 to 0.5 microns, for example, 0.1 to 0.2 microns in thickness.
  • the crystalline silicon in one embodiment, is 3 microns or less in thickness, for example, from greater than 0 to 2 microns.
  • One embodiment is a method comprising providing a glass substrate having a surface, spraying the surface with a slurry comprising abrasive particles and water to form an abraded surface, and etching the abraded surface to form a textured glass substrate.
  • Spraying comprises propelling the slurry with compressed air, hydrodynamic pressure, or a combination thereof.
  • Spraying can comprise using an 8 mm diameter nozzle, a liquid flowrate of 10 liters per minute, and a compressed air pressure of from 2 to 4 bars to spray the slurry.
  • the spraying can be done by spraying the slurry from the nozzle at an angle normal to the surface.
  • One or more nozzles can be translated across the surface of the glass substrate.
  • the abrasive particles have an average diameter of from 1 micron to 20 microns, for example, 1 to 15 microns, for example, 1 to 10 microns. In one embodiment, the abrasive particles have a mesh size of from 400 to 1200. In one embodiment, the abrasive particles have a 600 mesh size, a particle size distribution of from 5 microns to 20 microns, and a median particle size of 10 microns.
  • the abrasive particles can comprise alumina, silicon carbide, or a combination thereof, or are alumina. Other types of particles can be used as abrasive particles, for example, any material which is capable of removing glass from the surface of the glass substrate.
  • the slurry can comprise from 20 to 40 weight percent alumina in water.
  • the glass substrate is a sodalime glass, a specialty glass, fused silica, an alkali- free glass, or a combination thereof.
  • etching comprises etching the abraded surface with an etching solution comprising HF and HC1.
  • the solution can be a 1:1:20 solution of HF:HC1:H 2 0.
  • the etching comprises etching the abraded surface for from 5 to 15 minutes.
  • the method can further comprise cleaning the textured glass substrate after the etching.
  • the etching could be performed by either dipping (in a bath with etching solution) and/or by spraying (with similar or same etching solution) .
  • the method further comprises masking select areas of the glass substrate prior to the spraying. Masking techniques as known in the art can be used.
  • the substrate is planar. In one embodiment, the glass substrate is transparent.
  • Photovoltaic devices can comprise the textured glass substrate made according to the described methods.
  • Figure 3 is a flow chart of an exemplary method 300.
  • a glass sheet is cut to size 28, the sheet is then sand blasted 30, the sand blasted sheet is then rinsed 32, the sheet is then etched 34, for example, by immersion in a bath or spray of etching solution, the etched sheet is then rinsed and dried 36, the edges of the sheet are then finished 38, and a PV cell is then deposited on the sheet 40.
  • the texture created on the glass superstrate is advantageously in a specific range of characteristic sizes and shapes in order to provide cell efficiency improvement without causing detrimental effects (ex. electrical shunts) .
  • a desired type of texture is a smooth crater, with a
  • characteristic size in the micrometer range (greater than 0 to 15 ⁇ , for example, 1 to 10 ⁇ ) .
  • This can be obtained by a first step of sandblasting which removes glass chips, leaving a surface with sharp angles.
  • the second step is acid etching, which preferentially starts on the edges and rounds them to lead to a smoother pattern.
  • two surface treatments are used to texture the surface of an initial sheet of glass.
  • This dual surface treatment may provide a texture that induces an improvement of the solar cell efficiency yield.
  • the first surface treatment comprises media blasting the glass surface with a stream of fine abrasive particles (mixed in a slurry with water and propelled with compressed air) .
  • This slurry enables using finer abrasive particles than with air only and also produces fewer fractures on the surface of the glass substrate (the water is possibly acting as a damping medium on the impacting particles) .
  • the second surface treatment is an acid etching step that partly modifies the texture obtained after the first step and restores the glass surface strength after media blasting, which causes micro cracks in the glass surface.
  • the result is producing a highly diffusive surface while maintaining the total transmittance . This may allow improvement of light usage by decreasing the amount of reflected rays.
  • the shape of the texture is believed to favorably orient the texture of the transparent conductive oxide deposited on the glass surface.
  • the slurry comprises alumina particles with a fine mesh (#600, corresponding to 5 to 20 ⁇ particle size, with a median size at 10 ⁇ ) .
  • Alumina is used for its hardness. Fine particle distribution is advantageous to create small chips on the glass. Larger size particles result in lower improvement of the cell efficiency.
  • the load of the solution is, in one embodiment, between 20 and 40 % by weight of alumina in water.
  • Figure 2 is an optical photo of features 200 of the spraying, for example, sandblasting step in an exemplary method.
  • the liquid flowrate is 10 liters per minute, and the air pressure is 2 to 4 bars.
  • the distance between the nozzle and the surface of the glass substrate 24, in this example, may range from 50 to 150 mm; this parameter may have a large impact on the resulting texture of the abraded surface.
  • the glass substrate in this example, is 2 by 6 inches.
  • the glass carrier 26 can be moved horizontally or vertically at a controlled and adjustable rate.
  • the impinging jet is directed normal to the surface of the glass substrate, the angle having a moderate incidence on the resulting texture of the abraded surface.
  • FIGS. 4A and 4B are scanning electron microscope (SEM) images of an exemplary abraded surface obtained after the sandblasting step.
  • Figure 4A is a top down view and Figure 4B is a cross sectional view.
  • the etching solution in one embodiment, comprises a combination of HF and HC1.
  • the etching solution can be made for the specific glass types used. Depending on glass type, various etching time is needed (ex. 1:1:20 solution of HF:HC1:H 2 0 requires 5-15 minutes of etching for display quality glass such as EagleXGTM) . All samples were rinsed (cleaned) after the etching step.
  • Figures 5A and 5B are SEM images of the surface obtained after sandblasting and etching steps in one embodiment.
  • Figure 5A is a top down view and Figure 5B is a cross
  • Figure 6 is a graph showing diffuse transmittance after sandblasting and etching for four typical textures: ultrahigh, high, medium and low haze textures (from top to bottom) .
  • Figure 7 is a graph showing angular scattering for an exemplary medium haze sandblasted and etched glass substrate.
  • Figure 8 is a graph showing angular scattering for an exemplary high haze sandblasted and etched glass substrate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Surface Treatment Of Glass (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)

Abstract

A method comprises providing a glass substrate having a surface; spraying the surface with a slurry comprising abrasive particles and water to form an abraded surface; and etching the abraded surface to form a textured glass substrate. The textured glass substrate can be used in photovoltaic cells. A photovoltaic device comprising a light scattering article comprises a glass substrate having a textured surface, wherein the surface comprises smooth craters having an average width of from 1 to 15 microns; a conductive material adjacent to the surface; and an active photovoltaic medium adjacent to the conductive material.

Description

LIGHT SCATTERING ARTICLES BY ABRASION AND ETCH
[ 0001 ] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No.
61/490306 filed May 26, 2011 the content of which is relied upon and incorporated herein by reference in its entirety.
BACKGROUND
Field
[ 0002 ] Embodiments relate generally to light scattering articles and more particularly to light scattering inorganic articles having textured surfaces and abrasive methods of making the textured surfaces useful for, for example,
photovoltaic cells.
Technical Background
[ 0003 ] Thin film amorphous/microcrystalline silicon (Si-tandem) type photovoltaic cells are based on the use of a glass sheet onto which an assembly of thin films (TCO, amorphous silicon, crystalline silicon and anti reflective coating) are
deposited. In Si-tandem PV solar cells, it is advantageous to obtain a high usage of incident light, which can be brought partly by the glass superstrate. Moreover, the texture of the TCO can have a direct and/or indirect impact on the overall cell quantum efficiency (Q.E.) yield. The glass superstrate, when textured, can be used to orient the texture of the TCO.
[ 0004 ] WO 2009/026648 Al (CSG Solar AG) describes abrasion and etch texturing of glass where the initial abrasion is done by sandblasting. It seems that the preferred method is dry sandblasting, and that wet sandblasting is added as a possible alternative. Orbital lapping is also mentioned as a possible texturing technique.
[0005] It would be advantageous to have light scattering textured glass substrates wherein abrasion and etching create a textured surface on the substrate. Further, it would be advantageous to create a texture on the surface of a glass substrate useful for Si-tandem photovoltaic cells.
SUMMARY
[0006] Light scattering articles and methods of making the light scattering articles, as described herein, address one or more of the above-mentioned disadvantages of conventional light scattering articles and/or methods and may provide one or more of the following advantages: simplicity and potential high throughput in manufacturing, flexibility in the final properties such as haze and diffusion, and the potential to texture only parts of the initial substrate by masking select areas of the glass substrate.
[0007] One embodiment is a method comprising providing a glass substrate having a surface, spraying the surface with a slurry comprising abrasive particles and water to form an abraded surface, and etching the abraded surface to form a textured glass substrate.
[0008] Another embodiment is a photovoltaic device comprising a light scattering article comprising a glass substrate having a textured surface, wherein the surface comprises smooth craters having an average width of from 1 to 10 microns; a conductive material adjacent to the particles; and an active photovoltaic medium adjacent to the conductive material.
[0009] Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the invention as described in the written description and claims hereof, as well as the appended drawings.
[0010] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed.
[0011] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment ( s ) of the invention and together with the description serve to explain the principles and operation of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention can be understood from the following detailed description either alone or together with the accompanying drawing figures .
[0013] Figure 1 is a schematic diagram of features of a Si- tandem PV solar cell, according to one embodiment.
[0014] Figure 2 is an optical photo of the sandblasting step in an exemplary method.
[0015] Figure 3 is a flow chart of an exemplary method.
[0016] Figures 4A and 4B are scanning electron microscope (SEM) images of an exemplary abraded surface obtained after the sandblasting step.
[0017] Figures 5A and 5B are SEM images of the surface obtained after sandblasting and etching steps, according to one embodiment .
[0018] Figure 6 is a graph showing diffuse transmittance after exemplary sandblasting and etching for four typical textures: ultra-high, high, medium and low haze textures (from top to bottom) .
[0019] Figure 7 is a graph showing angular scattering for an exemplary medium haze sandblasted and etched glass substrate
[0020] Figure 8 is a graph showing angular scattering for an exemplary high haze sandblasted and etched glass substrate.
DETAILED DESCRIPTION
[0021] Reference will now be made in detail to various embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0022] As used herein, the term "substrate" can be used to describe either a substrate or a superstrate depending on the configuration of the photovoltaic cell. For example, the substrate is a superstrate, if when assembled into a
photovoltaic cell, it is on the light incident side of a photovoltaic cell . The superstrate can provide protection for the photovoltaic materials from impact and environmental degradation while allowing transmission of the appropriate wavelengths of the solar spectrum. Further, multiple
photovoltaic cells can be arranged into a photovoltaic module.
[0023] As used herein, the term "adjacent" can be defined as being in close proximity. Adjacent structures may or may not be in physical contact with each other. Adjacent structures can have other layers and/or structures disposed between them.
[0024] One embodiment, as shown by the schematic diagram in Figure 1, are features 100 of a photovoltaic device, for example, a Si-tandem PV solar cell comprising a light
scattering article comprising a glass substrate 10 having a textured surface 11, wherein the surface comprises smooth craters having an average width of from 1 to 15 microns; a conductive material 12 adjacent to the surface; and an active photovoltaic medium adjacent to the conductive material. In this embodiment, the active photovoltaic medium is a Si-tandem
(amorphous silicon 14 , crystalline silicon 16 ) medium. The smooth craters can be random in size and some craters can be smaller or larger than 1 to 15 microns.
[ 0025] In one embodiment, the conductive material is a transparent conductive film. The transparent conductive film, for example, a transparent conductive oxide (TCO) can comprise a textured surface. The texture of the TCO can be conformal to the texture of the textured glass substrate. The active photovoltaic medium can be in physical contact with the transparent conductive film.
[ 0026] In one embodiment, the device further comprises a counter electrode 18 in physical contact with the active photovoltaic medium and located on an opposite surface of the active photovoltaic medium as the conductive material. The device can further comprise a back reflector 20 adjacent to the counter electrode. The texturing from the textured glass substrate can be conformal throughout all of the layers. The white arrows show light scattering through the textured layers of the photovoltaic device.
[ 0027 ] The TCO, in one embodiment, is from greater than 0 to 2 microns in thickness, for example, 0.5 microns to 1.5 microns, for example, 0.5 microns to 1 micron in thickness. The amorphous silicon, in one embodiment, is greater than 0 to 0.5 microns, for example, 0.1 to 0.2 microns in thickness. The crystalline silicon, in one embodiment, is 3 microns or less in thickness, for example, from greater than 0 to 2 microns.
[ 0028 ] One embodiment is a method comprising providing a glass substrate having a surface, spraying the surface with a slurry comprising abrasive particles and water to form an abraded surface, and etching the abraded surface to form a textured glass substrate.
[ 0029] Spraying, according to one embodiment, comprises propelling the slurry with compressed air, hydrodynamic pressure, or a combination thereof.
[ 0030 ] Spraying can comprise using an 8 mm diameter nozzle, a liquid flowrate of 10 liters per minute, and a compressed air pressure of from 2 to 4 bars to spray the slurry. The distance between the nozzle and the surface, in one
embodiment, is from 50 mm to 150 mm. The spraying can be done by spraying the slurry from the nozzle at an angle normal to the surface. One or more nozzles can be translated across the surface of the glass substrate.
[ 0031 ] In one embodiment, the abrasive particles have an average diameter of from 1 micron to 20 microns, for example, 1 to 15 microns, for example, 1 to 10 microns. In one embodiment, the abrasive particles have a mesh size of from 400 to 1200. In one embodiment, the abrasive particles have a 600 mesh size, a particle size distribution of from 5 microns to 20 microns, and a median particle size of 10 microns. The abrasive particles can comprise alumina, silicon carbide, or a combination thereof, or are alumina. Other types of particles can be used as abrasive particles, for example, any material which is capable of removing glass from the surface of the glass substrate.
[ 0032 ] The slurry can comprise from 20 to 40 weight percent alumina in water. In some embodiments, the glass substrate is a sodalime glass, a specialty glass, fused silica, an alkali- free glass, or a combination thereof. [0033] According to one embodiment, etching comprises etching the abraded surface with an etching solution comprising HF and HC1. The solution can be a 1:1:20 solution of HF:HC1:H20. In one embodiment, the etching comprises etching the abraded surface for from 5 to 15 minutes. The method can further comprise cleaning the textured glass substrate after the etching. The etching could be performed by either dipping (in a bath with etching solution) and/or by spraying (with similar or same etching solution) .
[0034] The method, according to one embodiment, further comprises masking select areas of the glass substrate prior to the spraying. Masking techniques as known in the art can be used.
[0035] According to one embodiment, the substrate is planar. In one embodiment, the glass substrate is transparent.
[0036] Photovoltaic devices can comprise the textured glass substrate made according to the described methods.
[0037] Figure 3 is a flow chart of an exemplary method 300. First, a glass sheet is cut to size 28, the sheet is then sand blasted 30, the sand blasted sheet is then rinsed 32, the sheet is then etched 34, for example, by immersion in a bath or spray of etching solution, the etched sheet is then rinsed and dried 36, the edges of the sheet are then finished 38, and a PV cell is then deposited on the sheet 40.
[0038] The texture created on the glass superstrate is advantageously in a specific range of characteristic sizes and shapes in order to provide cell efficiency improvement without causing detrimental effects (ex. electrical shunts) . A desired type of texture is a smooth crater, with a
characteristic size in the micrometer range (greater than 0 to 15 μιτι, for example, 1 to 10 μιτι) . This can be obtained by a first step of sandblasting which removes glass chips, leaving a surface with sharp angles. The second step is acid etching, which preferentially starts on the edges and rounds them to lead to a smoother pattern.
[ 0039] In one embodiment, two surface treatments are used to texture the surface of an initial sheet of glass. This dual surface treatment may provide a texture that induces an improvement of the solar cell efficiency yield. The first surface treatment comprises media blasting the glass surface with a stream of fine abrasive particles (mixed in a slurry with water and propelled with compressed air) . This slurry enables using finer abrasive particles than with air only and also produces fewer fractures on the surface of the glass substrate (the water is possibly acting as a damping medium on the impacting particles) .
[ 0040 ] The second surface treatment is an acid etching step that partly modifies the texture obtained after the first step and restores the glass surface strength after media blasting, which causes micro cracks in the glass surface. The result is producing a highly diffusive surface while maintaining the total transmittance . This may allow improvement of light usage by decreasing the amount of reflected rays. Finally, the shape of the texture is believed to favorably orient the texture of the transparent conductive oxide deposited on the glass surface.
[ 0041 ] Several different types of glass substrates were tested with the sandblasting-etching method as described herein for glass texturing for Si-tandem PV solar cells: EagleXG™, HPFS® fused silica, soda-lime, specialty glass for CdTe solar cells, etc. Due to the nature of mechanical abrading dependence on glass surface strength, textures made on some specialty high surface strength glasses show features that could not be made on traditional glasses such as soda-lime. These features are particularly favorable for light trapping and suitable for the growth of TCO/silicon layers.
[0042] In one embodiment, the slurry comprises alumina particles with a fine mesh (#600, corresponding to 5 to 20 μιτι particle size, with a median size at 10 μιτι) . Alumina is used for its hardness. Fine particle distribution is advantageous to create small chips on the glass. Larger size particles result in lower improvement of the cell efficiency. The load of the solution is, in one embodiment, between 20 and 40 % by weight of alumina in water.
[0043] Figure 2 is an optical photo of features 200 of the spraying, for example, sandblasting step in an exemplary method. For spraying, for example, for an 8 mm diameter nozzle 22, the liquid flowrate is 10 liters per minute, and the air pressure is 2 to 4 bars. The distance between the nozzle and the surface of the glass substrate 24, in this example, may range from 50 to 150 mm; this parameter may have a large impact on the resulting texture of the abraded surface. The glass substrate, in this example, is 2 by 6 inches. The glass carrier 26 can be moved horizontally or vertically at a controlled and adjustable rate. The impinging jet is directed normal to the surface of the glass substrate, the angle having a moderate incidence on the resulting texture of the abraded surface. Spraying time influences the surface fraction where abrasive impacts (craters) are created. After full coverage is reached, matter continues to be removed and seems to reproduce the same surface pattern. In a continuous process, the glass substrate is laid onto a carrier above which several nozzles are travelling back and forth to cover the full surface and provide a good homogeneity of the treatment. The time expected for the treatment of a Gen 5 sheet is expected to be 5 minutes on larger size equipment. [0044] Figures 4A and 4B are scanning electron microscope (SEM) images of an exemplary abraded surface obtained after the sandblasting step. Figure 4A is a top down view and Figure 4B is a cross sectional view.
[0045] Samples were etched after the sandblasting step to partly modify the texture obtained after the first step and to restore the glass surface strength. This step is needed after the first one since media blasting causes micro cracks in the glass surface. The etching solution, in one embodiment, comprises a combination of HF and HC1. The etching solution can be made for the specific glass types used. Depending on glass type, various etching time is needed (ex. 1:1:20 solution of HF:HC1:H20 requires 5-15 minutes of etching for display quality glass such as EagleXG™) . All samples were rinsed (cleaned) after the etching step.
[0046] Figures 5A and 5B are SEM images of the surface obtained after sandblasting and etching steps in one embodiment.
Figure 5A is a top down view and Figure 5B is a cross
sectional view.
[0047] Figure 6 is a graph showing diffuse transmittance after sandblasting and etching for four typical textures: ultrahigh, high, medium and low haze textures (from top to bottom) .
[0048] Figure 7 is a graph showing angular scattering for an exemplary medium haze sandblasted and etched glass substrate.
[0049] Figure 8 is a graph showing angular scattering for an exemplary high haze sandblasted and etched glass substrate.
[0050] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents .

Claims

CLAIMS What is claimed is:
1. A method comprising
providing a glass substrate having a surface;
spraying the surface with a slurry comprising abrasive particles and water to form an abraded surface; and
etching the abraded surface to form a textured glass substrate .
2. The method according to claim 1, wherein the spraying comprises propelling the slurry with compressed air, hydrodynamic pressure, or a combination thereof.
3. The method according to claim 2, wherein the spraying comprises using an 8 mm diameter nozzle, a liquid flowrate of 10 liters per minute, and a compressed air pressure of from 2 to 4 bars to spray the slurry.
4. The method according to claim 3, wherein the distance between the nozzle and the surface is from 50 mm to 150 mm.
5. The method according to claim 4, wherein the spraying comprises spraying the slurry from the nozzle at an angle normal to the surface.
6. The method accord to claim 2, wherein the spraying comprises translating one or more nozzles across the surface of the glass substrate.
7. The method according to claim 1, wherein the abrasive particles have an average diameter of from 1 micron to 20 microns .
8. The method according to claim 7, wherein the abrasive particles have a mesh size of from 400 to 1200.
9. The method according to claim 1, wherein the abrasive particles have a 600 mesh size, a particle size distribution of from 5 microns to 20 microns, and a median particle size of 10 microns.
10. The method according to claim 1, wherein the abrasive particles comprise alumina, silicon carbide, or a
combination thereof.
11. The method according to claim 10, wherein the slurry comprises from 20 to 40 weight percent alumina in water.
12. The method according to claim 1, wherein the glass substrate is a sodalime glass, a specialty glass, fused silica, an alkali-free glass, or a combination thereof.
13. The method according to claim 1, wherein the etching comprises etching the abraded surface with an etching solution comprising HF and HC1.
14. The method according to claim 13, wherein the solution is a 1:1:20 solution of HF:HC1:H20.
15. The method according to claim 13, wherein the etching comprises etching the abraded surface for from 5 to 15 minutes .
16. The method according to claim 1, further comprising cleaning the textured glass substrate after the etching.
17. The method according to claim 1, further comprising masking select areas of the glass substrate prior to the spraying .
18. A photovoltaic device comprising the textured glass substrate made according to claim 1.
19. A photovoltaic device comprising a light scattering article comprising a glass substrate having a textured surface, wherein the surface comprises smooth craters having an average width of from 1 to 15 microns; a conductive material adjacent to the particles; and an active
photovoltaic medium adjacent to the conductive material.
20. The device according to claim 19, wherein the
conductive material is a transparent conductive film.
21. The device according to claim 20, wherein the
transparent conductive film comprises a textured surface.
22. The device according to claim 19, wherein the active photovoltaic medium is in physical contact with the
transparent conductive film.
23. The device according to claim 19, further comprising a counter electrode in physical contact with the active photovoltaic medium and located on an opposite surface of the active photovoltaic medium as the conductive material.
PCT/US2012/039233 2011-05-26 2012-05-24 Light scattering articles by abrasion and etch WO2012162446A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161490306P 2011-05-26 2011-05-26
US61/490,306 2011-05-26

Publications (1)

Publication Number Publication Date
WO2012162446A1 true WO2012162446A1 (en) 2012-11-29

Family

ID=46201853

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2012/039233 WO2012162446A1 (en) 2011-05-26 2012-05-24 Light scattering articles by abrasion and etch

Country Status (2)

Country Link
TW (1) TW201305067A (en)
WO (1) WO2012162446A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104230172A (en) * 2013-06-06 2014-12-24 株式会社不二制作所 Method for Processing Surface of Light-Transmitting Glass and Light-Transmitting Glass Processed by said Method
EP3012970A4 (en) * 2013-06-17 2017-01-18 Kaneka Corporation Solar cell module and method for producing solar cell module
WO2018100270A1 (en) * 2016-12-01 2018-06-07 Sa Gerard Pariche Process and facility for frosting a glass container
WO2018162546A1 (en) * 2017-03-10 2018-09-13 Gebr. Schmid Gmbh Method for producing textured wafers and roughening spray jet treatment device
CN109111859A (en) * 2018-10-30 2019-01-01 秦皇岛市大龙建材有限公司 Glass polishing solution
CN109719630A (en) * 2019-03-18 2019-05-07 郑州恒昊光学科技有限公司 One-step method prepares glare proof glass new process
EP3632618A1 (en) * 2018-10-04 2020-04-08 Politecnico di Milano Abrasive water-jet cutting machine and method, and composition comprising abrasive material
WO2025003700A1 (en) 2023-06-29 2025-01-02 Pilkington Group Limited Method for affecting glass strength

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10381973B2 (en) * 2017-05-17 2019-08-13 Tesla, Inc. Uniformly and directionally colored photovoltaic modules
CN115284178A (en) * 2022-07-08 2022-11-04 中国科学院光电技术研究所 A low-cost fabrication method for highly integrated laser scattering devices

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB683596A (en) * 1950-06-23 1952-12-03 Rauland Corp Improvements in or relating to cathode ray tubes
KR900004123B1 (en) * 1988-01-14 1990-06-16 한국유리공업 주식회사 Acidic solution for treating a glass surface to be low reflected and treating method therefor
JPH1168131A (en) * 1997-08-25 1999-03-09 Citizen Watch Co Ltd Manufacture of solar battery
JP2003069059A (en) * 2001-08-28 2003-03-07 Kyocera Corp Method for roughening glass substrate and thin-film polycrystalline silicon solar cell using the glass substrate
JP2003192388A (en) * 2001-12-25 2003-07-09 Nippon Sheet Glass Co Ltd Method for manufacturing low reflective glass substrate and low reflective glass obtained by the method
WO2009026648A1 (en) 2007-08-31 2009-03-05 Csg Solar Ag Abrasion-etch texturing of glass
KR20100097893A (en) * 2009-02-27 2010-09-06 주식회사 티지솔라 Method for manufacturing solar cell using substrare having concavo-convex activestructure

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB683596A (en) * 1950-06-23 1952-12-03 Rauland Corp Improvements in or relating to cathode ray tubes
KR900004123B1 (en) * 1988-01-14 1990-06-16 한국유리공업 주식회사 Acidic solution for treating a glass surface to be low reflected and treating method therefor
JPH1168131A (en) * 1997-08-25 1999-03-09 Citizen Watch Co Ltd Manufacture of solar battery
JP2003069059A (en) * 2001-08-28 2003-03-07 Kyocera Corp Method for roughening glass substrate and thin-film polycrystalline silicon solar cell using the glass substrate
JP2003192388A (en) * 2001-12-25 2003-07-09 Nippon Sheet Glass Co Ltd Method for manufacturing low reflective glass substrate and low reflective glass obtained by the method
WO2009026648A1 (en) 2007-08-31 2009-03-05 Csg Solar Ag Abrasion-etch texturing of glass
KR20100097893A (en) * 2009-02-27 2010-09-06 주식회사 티지솔라 Method for manufacturing solar cell using substrare having concavo-convex activestructure

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 199127, Derwent World Patents Index; AN 1991-199021, XP002681465 *
DATABASE WPI Week 199920, Derwent World Patents Index; AN 1999-239379, XP002681463 *
DATABASE WPI Week 200331, Derwent World Patents Index; AN 2003-321790, XP002681462 *
DATABASE WPI Week 200359, Derwent World Patents Index; AN 2003-622047, XP002681466 *
DATABASE WPI Week 201059, Derwent World Patents Index; AN 2010-K90597, XP002681464 *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104230172A (en) * 2013-06-06 2014-12-24 株式会社不二制作所 Method for Processing Surface of Light-Transmitting Glass and Light-Transmitting Glass Processed by said Method
EP3012970A4 (en) * 2013-06-17 2017-01-18 Kaneka Corporation Solar cell module and method for producing solar cell module
US10177259B2 (en) 2013-06-17 2019-01-08 Kaneka Corporation Solar cell module and method for producing solar cell module
WO2018100270A1 (en) * 2016-12-01 2018-06-07 Sa Gerard Pariche Process and facility for frosting a glass container
FR3059580A1 (en) * 2016-12-01 2018-06-08 Sa Gerard Pariche METHOD AND INSTALLATION FOR DEPOLISHING GLASS CONTAINER
WO2018162546A1 (en) * 2017-03-10 2018-09-13 Gebr. Schmid Gmbh Method for producing textured wafers and roughening spray jet treatment device
EP3632618A1 (en) * 2018-10-04 2020-04-08 Politecnico di Milano Abrasive water-jet cutting machine and method, and composition comprising abrasive material
US11904437B2 (en) 2018-10-04 2024-02-20 Politecnico Di Milano Abrasive water-jet cutting machine
CN109111859A (en) * 2018-10-30 2019-01-01 秦皇岛市大龙建材有限公司 Glass polishing solution
CN109719630A (en) * 2019-03-18 2019-05-07 郑州恒昊光学科技有限公司 One-step method prepares glare proof glass new process
WO2025003700A1 (en) 2023-06-29 2025-01-02 Pilkington Group Limited Method for affecting glass strength

Also Published As

Publication number Publication date
TW201305067A (en) 2013-02-01

Similar Documents

Publication Publication Date Title
WO2012162446A1 (en) Light scattering articles by abrasion and etch
US20120003779A1 (en) Abrasion-etch texturing of glass
Diedenhofen et al. Broad‐band and omnidirectional antireflection coatings based on semiconductor nanorods
KR101510578B1 (en) Surface-textured conductive glass for solar cells, and preparation method and application thereof
US20110126890A1 (en) Textured superstrates for photovoltaics
KR101986390B1 (en) Method for processing surface of light transmitting glass and light transmitting glass
US20110209752A1 (en) Microstructured glass substrates
CN101246924A (en) Solar cell with substrate having textured surface
CA2903248C (en) Antireflective coating for glass applications and method of forming same
Alam et al. Super hydrophilic nano particulate coating for solar PV module
JP2006005021A (en) Substrate with rough thin-film and its manufacturing method
US8663732B2 (en) Light scattering inorganic substrates using monolayers
Alam et al. Silica nano-particulate coating having self-cleaning and antireflective properties for PV modules
CN114573240B (en) Front plate glass, preparation method thereof, photovoltaic module and photovoltaic curtain wall
WO2018222661A1 (en) High transparency, high haze nanostructured structures
JP6293138B2 (en) Solar cell module and method for manufacturing solar cell module
JP2004082285A (en) Method for roughening glass substrate for solar cell element
CN102952521A (en) Shot blasting material for silicon substrate surface treatment and method for preparing silicon substrate
Thompson et al. Nanostructured PVP/SiO 2 antireflective coating for solar panel applications
Asokan et al. Anti-Reflection Coating
Ragavendran et al. Anti‐Reflection Coating
US20110120555A1 (en) Photovoltaic devices and light scattering superstrates

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12725242

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12725242

Country of ref document: EP

Kind code of ref document: A1