WO2011006829A1

WO2011006829A1 - Method for producing a coated and reflection-reducing pane

Info

Publication number: WO2011006829A1
Application number: PCT/EP2010/059805
Authority: WO
Inventors: Marcus Neander; Katja Werner; Bianca Bergs; Marc Maurer
Original assignee: Saint-Gobain Glass France
Priority date: 2009-07-17
Filing date: 2010-07-08
Publication date: 2011-01-20
Also published as: EP2454211A1; DE102009026197B4; CN102471141A; DE102009026197A1

Abstract

The invention relates to a method for producing an optically transparent glass pane, comprising an electrically conductive layer and an anti-reflection layer, wherein a. an optically transparent, electrically conductive layer (3) is applied to at least a portion of the surface of the glass substrate (2) and b. an anti-reflection layer (1) is generated on the non-coated surface of the glass substrate (2), in that a solution of an acid and/or base is applied to the surface of the glass substrate (2).

Description

Process for producing a coated and reflection-reduced disk

description

The invention relates to a method for producing a coated and reflection-reduced disc, a disc produced by the method according to the invention and their use.

In addition to the high optical transparency which is required in many cases, many discs also show strong light reflections. When light hits an interface of media of different refractive index, a portion of the incident light is reflected. Depending on the light source, wavelength and angle of incidence, the reflection can be considerable. For example, sunlight reflection on buildings or vehicles ahead can dazzle other road users. Even in photovoltaics, light reflection is undesirable because it reduces the amount of light on the photocell surface and reduces the efficiency of the solar cell.

Basically, several methods are used for the reflection reduction of slices. The reflection reduction of slices is in many cases based on the creation of a porous, structured layer on the glass surface. This porous, structured layer can be produced by etching with a suitable acid or base. A porous SiO ₂ layer can be produced by deposition of SiO ₂ on the glass surface, for example in a sol-gel process. Combinations of the two methods of etching and deposition are also possible.

The reflection-reducing properties are also of importance in the case of panes with optically transparent, electrically conductive coatings, such as, for example, transparent conductive oxides (TCO). By reducing the scattered light, the absolute transmission of these layers can be further increased. However, the porous, structured layer on the glass surface often requires additional and adapted process steps. The surface structure of a previously etched disk changes the deposition of the optically transparent, electrically conductive layer in many cases. This adjustment and, if necessary, amendment of Process conditions during the deposition of the optically transparent, electrically conductive coating make the production of the coated pane more expensive.

US 2,486,431 A discloses a method for producing a low-reflective glass surface. The glass surface is etched with an H ₂ SiF ₆ solution. Depending on the duration of the etching process, the glass surface is removed to varying degrees and thus the optical properties of the surface are adjusted and varied.

DE 822 714 B discloses a method for producing a reflection-reducing film on the surface of a glass article. For this purpose, the glass article is immersed in a solution of H ₂ SiF ₆ and colloidally dissolved SiO ₂ . Depending on the F ^" and SiO ₂ concentration, the wafer surface is ablated (etched) and / or built up.

EP 1 056 136 B1 discloses a substrate for a solar cell comprising at least a glass plate, a first and second base coating film and a conductive film. The first base coat film contains at least metal oxides such as tin oxide, titanium oxide, indium oxide or zinc oxide.

US2008 / 0314442 A1 discloses a transparent substrate with an optically transparent electrode consisting of at least two layers. The first transparent, electrically conductive layer contains a non-doped metal oxide, such as tin oxide. The second transparent, electrically conductive layer, in contrast, contains a doped metal oxide.

US2008 / 0308146 A1 discloses a photovoltaic article having a front electrode on a textured glass substrate. The texturing of the glass substrate is carried out before the application of the front electrode by a mechanical roller at 570 ⁰ C to 750 ⁰ C or by etching with an acid. The front electrode is then applied via a pyrolysis process.

The object of the invention is to provide a method for producing a coated and reflection-reduced disc, which allows a coating of the disc with an optically transparent, electrically conductive coating regardless of the existing or later texturing of the disc. The object of the present invention is achieved by an optically transparent glass pane, process for their preparation, and their use according to the independent claims 1, 13 and 15. Preferred embodiments will become apparent from the dependent claims.

The method for producing a coated, reflection-reduced pane comprises, in a first step, the application of an optically transparent, electrically conductive layer on at least a portion of the surface of a glass substrate. This optically transparent, electrically conductive layer preferably has an average transmission of more than 75%, preferably more than 80% (as energy transmission according to DIN-EN 410: 1998) for light of wavelengths from 300 nm to 1300 nm.

In a second step, an antireflection layer is formed on the uncoated surface of the glass substrate by applying a solution of an acid and / or base to the surface of the glass substrate. The solution of an acid and / or base is preferably also applied to the surface of the glass substrate on the surface of the glass substrate provided with an optically transparent, electrically conductive layer. The acid and / or alkali is preferably selected so that the glass surface is etched, but at the same time the optically transparent, electrically conductive layer is not attacked by the acid and / or alkali. Metal oxides have, in particular, depending on their redox potential, a sufficient stability to acids and bases. This property can also be exploited for metallic layers which form corresponding passivated surfaces.

The antireflection layer is preferably produced by completely immersing the glass substrate containing the optically transparent electrically conductive layer in a solution of an acid and / or base. Completely includes in the context of the invention also not treated contact points of holding devices on the glass substrate with a.

The antireflection layer can alternatively also be produced in that a solution of an acid and / or base is sprayed onto the glass substrate with the optically transparent, electrically conductive layer.

The acid and / or base applied to the surface of the glass substrate preferably contains HF, H ₂ SiF ₆ , (SiO ₂ ) _m ^* nH ₂ O, HCl, H ₂ SO ₄ , H ₃ PO ₄ , HNO ₃ , CF ₃ COOH, CCI ₃ COOH, HCOOH, CH ₃ COOH, NaOH, KOH, Ca (OH) ₂ and / or mixtures thereof. The acid and / or base applied to the surface of the glass substrate particularly preferably contains HF and / or H ₂ SiF ₆ . With these acids, particularly good results are achieved in the dipping process.

The optically transparent, electrically conductive layer is preferably applied by CVD (chemical vapor deposition), CLD (chemical liquid deposition), PVD (physical vapor deposition) and / or combinations thereof on the glass substrate. The optically transparent, electrically conductive layer is particularly preferably applied by spraying method, pyrolysis method, sputtering, magnetron sputtering, sol-gel method, ion beam method, electron beam method, vapor deposition and / or combinations thereof on the glass substrate.

After the generation of the antireflection layer, the optically transparent, electrically conductive layer preferably has a sheet resistance of <20 Ω /, more preferably of <15 Ω /, and most preferably of <10 Ω / □.

The optically transparent, electrically conductive layer preferably has a haze of <20%, preferably <10%, particularly preferably <5%, after the generation of the antireflection layer.

The optically transparent, electrically conductive layer preferably has a R.M.S roughness depth of 3 nm to 50 nm, preferably 5 nm to 20 nm, after the generation of the antireflection layer. The R.M.S roughness (Root Mean Square) describes the root mean square of the roughness depth. The R.M.S roughness depth is preferably determined using an AFM (Atomic Force Microscope) microscope.

The optically transparent, electrically conductive layer is preferably applied to the glass substrate with a layer thickness of 10 nm to 1500 nm, particularly preferably with a layer thickness of 400 nm to 800 nm.

The optically transparent, electrically conductive layer is preferably by application of tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO, SnO ₂ : F), antimony-doped tin oxide (ATO, SnO ₂ : Sb), silver, gold, tin, Tungsten, copper, silicon, carbon nanotubes and / or optically transparent, electrically conductive polymers and / or mixtures thereof.

The optically transparent, electrically conductive polymers preferably contain poly (3,4-ethylenedioxythiophene), polystyrene sulfonate, poly (4,4-dioctylcylopentadithiophene), iodo, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, mixtures and / or copolymers thereof.

The glass substrate preferably has an average transmission in the wavelength range from 300 nm to 1300 nm of> 80%, preferably of> 90%.

The antireflection layer preferably has an average transmission in the wavelength range from 300 nm to 1300 nm of> 80%, preferably of> 90%.

The antireflection layer is preferably produced with a layer thickness of 10 nm to 1000 nm, particularly preferably 50 nm to 200 nm. Good results are achieved in this layer thickness range.

The glass substrate preferably contains flat glass (float glass), quartz glass, borosilicate glass, soda lime glass and / or mixtures thereof. Good results are achieved with these glasses.

The glass substrate preferably contains 0.001% by weight to 0.05% by weight of Fe (III) as Fe ₂ O ₃ and / or 0.0005% by weight to 0.005% by weight of Fe (II) as FeO. These Fe (III) and Fe (II) concentrations are particularly advantageous.

A cover layer is preferably applied to the optically transparent, electrically conductive layer. The cover layer may contain scratch-resistant layers such as Si ₃ N ₄ and / or acids and / or bases resistant polymers such as epoxy resins, etching and / or etching.

The glass substrate is preferably biased after the formation of the antireflection layer. The biasing is preferably carried out as described in DE10 2009 025 788 A1. The disc is heated to a temperature of 500 ⁰ C to 800 ⁰ C. The heating of the disk is followed by rapid cooling (quenching, for example by a cold jet of air) the heated, etched disk. The surface of the disk cools faster than the core zone, so that tensions form in the glass. The tensions increase the stability and strength of the glass. Heating and rapid cooling together form the tempering process of the process according to the invention.

The invention further relates to an optically transparent glass pane having an electrically conductive layer and an antireflection layer. The glass pane comprises at least one optically transparent, electrically conductive layer on at least a portion of the surface of a glass substrate and an antireflection layer on the non-coated surface of the glass substrate. The antireflection layer has a minimum light reflection of 0.5% to 7%, preferably 1% to 5%. The light reflection is determined at a wavelength of 300 nm to 1300 nm and a reflection angle of 1 ° to 40 °. The optically transparent glass pane has the properties described above. The minimum light reflection of less than 7% and light reflection angle of less than 40 ° allow a high light transmission.

The invention further relates to an optically transparent glass pane obtained by the method according to the invention with an electrically conductive layer and an antireflection layer.

The invention further relates to the use of an optically transparent glass pane having an electrically conductive layer and an antireflection layer in photovoltaics, preferably in solar cells, screens, vehicle glazing and / or structural glazing.

In the following the invention with reference to a drawing and an embodiment, and comparative example will be explained in more detail.

An embodiment of the invention is illustrated in the drawings and will be described in more detail below.

Show it:

1 shows a cross section of the optically transparent glass pane according to the invention with an antireflection coating (1), glass substrate (2) and an optically transparent, electrically conductive layer (3) and

Figure 2 is a flow diagram of a preferred embodiment of the method according to the invention. Figure 1 shows a cross section of the glass substrate (2) with the applied electrically conductive layer (3) and the anti-reflection layer (1). The antireflection coating (1) lowers the proportion of the light reflected on the glass surface. This increases the proportion of light (transmission) which can pass through the glass substrate (2) and then the optically transparent, electrically conductive layer (3).

FIG. 2 shows a flow chart of a preferred embodiment of the method according to the invention. In a first step, the glass substrate (2) is provided on one side with an optically transparent, electrically conductive layer (3), in this case an optically transparent, conductive oxide (TCO). TCO can be applied by various methods such as CVD or PVD, for example sputtering. The layer thickness of the TCO is preferably 400 nm to 800 nm. The TCO coating can be provided with an acid-resistant covering layer (4) depending on the acid used. In a second step, the glass substrate (2) with the TCO coating (3) is completely immersed in a hydrofluoric acid bath. The hydrofluoric acid etches the uncoated glass surface of the glass substrate (2) and generates an antireflection coating (1) thereon. The TCO layer (3) is not or only slightly attacked by the relatively weak acid HF, so that the TCO layer (3) shows no significant changes in its physical or chemical properties. The now coated glass substrate (2) is then rinsed with distilled water and dried.

The invention is explained in more detail below with reference to an example of the method according to the invention and of a comparative example.

In two series of experiments, the transmission, turbidity, efficiency increase and the sheet resistance of a disk produced by the process according to the invention (Example 1) and a comparative example (Example 2) were compared. Both discs (Example 1 and 2) containing a diamond ^® glass (2) from Saint-Gobain Glass having a thickness of 3.2 mm. Both disks (Examples 1 and 2) contained on one side an optically transparent, electrically conductive SnO ₂ : F layer (3) with a layer thickness of approximately 500 nm. The SnO ₂ : F layer (3) was applied as in US2008 / 0314442 A1 described.

The disc produced by the process according to the invention (Example 1) was then precessed with an HF solution (2 wt.%) For 1 to 10 min, rinsed with deionized water and with H ₂ SiF ₆ (1, 25 mol / l) for Etched in a dip bath for 30 minutes to 120 minutes. In both etching processes, the pane according to the invention (Example 1) was also completely immersed in the acid with the optically transparent, electrically conductive coating.

The disc of Comparative Example (Example 2) was not etched and contained no antireflection layer (1).

The results of the transmission (T), haze, efficiency increase (E.I), minimal reflection (R _min at 20 ° / 300 nm to 1300 nm), and the sheet resistance (rsq) are summarized in Table 1. Transmission, Efficiency Increase and Reflectance values were determined using a Lambda 900 WKL (Perkin Elmer, Waltham, Massachusetts 02451, USA). The Efficiency Increase (E.I) was calculated according to formula (1)

_EI _ ΣJ _AR x QEx N -ΣJ _ref x QEx N

ΣX _ef x QEx N (1)

where QE = quantum efficiency in%, T _ref = transmission reference glass, T _AR = transmission of the disc according to the invention and N = number of incident photons in the wavelength range λ from 300 nm to 1300 nm.

The haze was determined using a Haze-Gard Plus (BYK Gardner GmbH, 82538 Geretsried, Germany).

Table 1: Transmission (T), Efficiency lncrease (El), Haze, the sheet resistance (rsq) and the minimum reflection (R _min at 20 ° / 300 nm to 1300 nm) of the inventive example (Example 1) and Comparative Example (Example 2)

The sheet resistance (rsq) was determined by the 4 point method. The pane of the invention (Example 1) had a significantly higher transmission (T) and a significantly lower proportion of scattered light (R) than the comparative example (Example 2). Thus, in the example according to the invention (Example 1), a high efficiency increase (E.I.), dependent on these quantities, was found to be 3.64%. This Efficiency Increase (E.I), for example, has a direct effect on the efficiency of a solar module which uses a glass substrate according to the invention. The constant sheet resistance (rsq) and the barely changing haze showed that the optically transparent, electrically conductive layer (3) was not attacked or abraded by the acid treatment. These results were surprising and not obvious to the person skilled in the art.

LIST OF REFERENCE NUMBERS

(1) antireflection coating,

(2) glass substrate,

(3) optically transparent, electrically conductive coating and

(4) topcoat.

Claims

claims

1 . A process for producing an optically transparent glass sheet comprising an electrically conductive layer and an antireflection layer, wherein a. on at least a portion of the surface of a glass substrate (2) an optically transparent, electrically conductive layer (3) is applied and b. an antireflection layer (1) is formed on the uncoated surface of the glass substrate (2) by applying a solution of an acid and / or base to the surface of the glass substrate (2).

2. The method according to claim 1, wherein the antireflection layer (1) is produced by immersing the glass substrate (2) containing the optically transparent electrically conductive layer (3) in a solution of an acid and / or base.

3. The method according to claim 1, wherein the antireflection layer (1) is produced by spraying a solution of an acid and / or base onto the glass substrate (2) containing the optically transparent electrically conductive layer (3).

4. The method according to any one of claims 1 to 3, wherein acid and / or base containing HF, H ₂ SiF ₆ , (SiO ₂ ) _m ^* nH ₂ O, HCl, H ₂ SO ₄ , H ₃ PO ₄ , HNO ₃ , CF ₃ COOH, CCI ₃ COOH, HCOOH, CH ₃ COOH, NaOH, KOH, Ca (OH) ₂ and / or mixtures thereof are applied to the surface of the glass substrate (2).

5. The method according to any one of claims 1 to 4, wherein the optically transparent, electrically conductive layer (3) by CVD, CLD, PVD, spraying, pyrolysis, sputtering, Magentronsputtering, SoI-GeI method, Inonenstrahlverfahren electron beam method, vapor deposition and / or combinations it is applied.

6. The method according to any one of claims 1 to 5, wherein the optically transparent, electrically conductive layer (3) after the generation of the antireflection layer (1) has a sheet resistance of <20 Ω /, preferably <15 Ω /, more preferably <10 Ω / having.

7. The method according to any one of claims 1 to 6, wherein the optically transparent, electrically conductive layer (3) after the production of the antireflection layer (1) has a haze of <20%, preferably <10%, particularly preferably <5% and / or has an RMS roughness of 3 nm to 50 nm, preferably 5 nm to 20 nm.

8. The method according to any one of claims 1 to 7, wherein the optically transparent, electrically conductive layer (3) having a layer thickness of 10 nm to 1500 nm, preferably 400 nm to 800 nm is applied.

9. The method according to any one of claims 1 to 8, wherein the optically transparent, electrically conductive layer (3) by applying tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO, SnO ₂ : F), antimony-doped tin oxide (ATO, SnO ₂ : Sb), silver, gold, tin, tungsten, copper, silicon, carbon nanotubes, optically transparent, electrically conductive polymers poly (3,4-ethylenedioxythiophene), polystyrene sulfonate, poly ( 4,4-dioctylcyclopentadithiophene), iodo, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, mixtures and / or copolymers thereof.

10. The method according to any one of claims 1 to 9, wherein the antireflection layer (1) is produced with a layer thickness of 10 nm to 1000 nm, preferably from 50 nm to 200 nm.

1 1. Method according to one of claims 1 to 10, wherein a cover layer (4) is applied to the optically transparent, electrically conductive layer (3).

12. The method according to any one of claims 1 to 1 1, wherein the glass substrate (2) after the production of the antireflection layer (1) is biased.

13. An optically transparent glass pane comprising:

a. an optically transparent, electrically conductive layer (3) on at least a portion of the surface of a glass substrate (2) and

b. an antireflection layer (1) on the non-coated surface of the glass substrate (2) with a minimum light reflection of 0.5% to 7% determined at a mean wavelength of 300 nm to 1300 nm and a reflection angle of 1 ° to 40 °.

14. An optically transparent glass pane according to claim 13, which has a cover layer (4) on the optically transparent, electrically conductive layer (3).

15. Use of an optically transparent glass pane according to claim 13 or 14 in photovoltaics, preferably in solar modules, screens, vehicle glazing and / or glazing.