JP2016172690A - Glass substrate - Google Patents

Glass substrate Download PDF

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JP2016172690A
JP2016172690A JP2016132473A JP2016132473A JP2016172690A JP 2016172690 A JP2016172690 A JP 2016172690A JP 2016132473 A JP2016132473 A JP 2016132473A JP 2016132473 A JP2016132473 A JP 2016132473A JP 2016172690 A JP2016172690 A JP 2016172690A
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glass
glass substrate
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solar cell
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JP6210136B2 (en
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長嶋　達雄
Tatsuo Nagashima
達雄 長嶋
裕 黒岩
Yutaka Kuroiwa
裕 黒岩
玲大 臼井
Reo Usui
玲大 臼井
剛 富澤
Takeshi Tomizawa
剛 富澤
健 岡東
Takeshi Okato
健 岡東
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AGC Inc
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Asahi Glass Co Ltd
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    • 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
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
    • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
    • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container 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
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/095—Glass compositions containing silica with 40% to 90% silica, by weight containing rare earths
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
    • H01L31/036—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes
    • H01L31/0392—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate
    • H01L31/03923—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate including AIBIIICVI compound materials, e.g. CIS, CIGS
    • 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
    • Y02E10/541—CuInSe2 material PV cells
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

PROBLEM TO BE SOLVED: To provide a glass substrate having high power generation efficiency, a high glass transition point temperature, a predetermined average thermal expansion coefficient, a low glass density, and the ability to prevent devitrification at the production of a plate glass, which are well balanced.SOLUTION: A glass substrate comprises, in mass% in terms of the following oxides, SiOof more than 60%, ZrOof 0.5-5%, NaO of 4-8%, AlO, MgO, and CaO with MgO+CaO+SrO+BaO of 13.1% or less, NaO+KO of 12.5% or less, SiO-AlOof 43% or more and less than 50%, and KO/NaO of 1.3 or less. The glass substrate has a glass transition temperature of 640°C or higher, and a density of 2.7 g/cmor less.SELECTED DRAWING: Figure 1

Description

本発明は、ガラス基板に関し、詳しくはガラス基板の間に光電変換層が形成されている太陽電池用のガラス基板に関する。より詳しくは、ガラス基板として典型的にはガラス基板とカバーガラスとを有し、ガラス基板上に１１族、１３族、１６族元素を主成分とした光電変換層が形成されているＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用のガラス基板に関するものである。   The present invention relates to a glass substrate, and more particularly to a glass substrate for a solar cell in which a photoelectric conversion layer is formed between glass substrates. More specifically, the glass substrate typically includes a glass substrate and a cover glass, and a Cu-In in which a photoelectric conversion layer mainly composed of a group 11, group 13, or group 16 element is formed on the glass substrate. The present invention relates to a glass substrate for a -Ga-Se solar cell.

カルコパイライト結晶構造を持つ１１−１３族、１１−１６族化合物半導体や立方晶系あるいは六方晶系の１２−１６族化合物半導体は、可視から近赤外の波長範囲の光に対して大きな吸収係数を有している。そのために、高効率薄膜太陽電池の材料として期待されている。代表的な例としてＣｕ（Ｉｎ，Ｇａ）Ｓｅ２（以下、「ＣＩＧＳ」または「Ｃｕ−Ｉｎ−Ｇａ−Ｓｅ」と記述する。）やＣｄＴｅがあげられる。 Group 11-13, 11-16 compound semiconductors having a chalcopyrite crystal structure and cubic or hexagonal 12-16 group compound semiconductors have a large absorption coefficient for light in the visible to near-infrared wavelength range. have. Therefore, it is expected as a material for high-efficiency thin film solar cells. Typical examples include Cu (In, Ga) Se 2 (hereinafter referred to as “CIGS” or “Cu—In—Ga—Se”) and CdTe.

ＣＩＧＳ薄膜太陽電池（以下、「ＣＩＧＳ太陽電池」ともいう）では、安価であることと平均熱膨張係数がＣＩＧＳ化合物半導体のそれに近いこととから、ソーダライムガラスが基板として用いられ、太陽電池が得られている。
また、効率の良い太陽電池を得るため、高温の熱処理温度に耐えうるガラス材料の提案もされている（特許文献１参照）。 In CIGS thin film solar cells (hereinafter also referred to as “CIGS solar cells”), soda lime glass is used as a substrate because of its low cost and an average coefficient of thermal expansion close to that of CIGS compound semiconductors. It has been.
Moreover, in order to obtain an efficient solar cell, the glass material which can endure high heat processing temperature is also proposed (refer patent document 1).

日本国特開平１１−１３５８１９号公報Japanese Patent Laid-Open No. 11-135819

ガラス基板にはＣＩＧＳ光電変換層（以下、「ＣＩＧＳ層」ともいう）が形成されるが、特許文献１に開示されているように、発電効率の良い太陽電池を作製するにはより高温での熱処理が好ましく、ガラス基板には高温での熱処理に耐えうることが要求される。特許文献１では比較的徐冷点の高いガラス組成物が提案されているが、特許文献１に記載された発明が高い発電効率を有するとは必ずしもいえない。
本発明者等はガラス基板のアルカリを所定範囲で増やすことによって発電効率を高くすることができることを発見したが、アルカリの増量はガラス転移点温度（Ｔｇ）の低下を招くという問題があった。 A CIGS photoelectric conversion layer (hereinafter also referred to as “CIGS layer”) is formed on the glass substrate. However, as disclosed in Patent Document 1, a solar cell with high power generation efficiency is produced at a higher temperature. Heat treatment is preferable, and the glass substrate is required to withstand heat treatment at a high temperature. Patent Document 1 proposes a glass composition having a relatively high annealing point, but the invention described in Patent Document 1 does not necessarily have high power generation efficiency.
The present inventors have found that the power generation efficiency can be increased by increasing the alkali of the glass substrate within a predetermined range, but there is a problem that an increase in alkali causes a decrease in the glass transition temperature (T g ). .

一方で、ガラス基板上のＣＩＧＳ層の製膜中または製膜後の剥離を防止するためには、ガラス基板は、所定の平均熱膨張係数を有することが求められる。
さらに、ＣＩＧＳ太陽電池の製造および使用の観点から、ガラスの軽量化、また板ガラス生産時に失透しないことが求められる。
このようにＣＩＧＳ太陽電池に使用されるガラス基板において高い発電効率、高いガラス転移点温度、所定の平均熱膨張係数、低いガラス密度、及び板ガラス生産時の失透防止の特性をバランスよく有することは困難であった。 On the other hand, in order to prevent peeling during or after the formation of the CIGS layer on the glass substrate, the glass substrate is required to have a predetermined average thermal expansion coefficient.
Furthermore, from a viewpoint of manufacture and use of a CIGS solar cell, it is required to reduce the weight of the glass and not devitrify during the production of the plate glass.
As described above, the glass substrate used in the CIGS solar cell has a good balance of high power generation efficiency, high glass transition temperature, predetermined average thermal expansion coefficient, low glass density, and devitrification prevention characteristics during production of sheet glass. It was difficult.

本発明は、高い発電効率、高いガラス転移点温度、所定の平均熱膨張係数、低いガラス密度、及び板ガラス生産時の失透防止の特性をバランスよく有するガラス基板を提供することを目的とする。   An object of the present invention is to provide a glass substrate having a good balance of high power generation efficiency, high glass transition temperature, predetermined average thermal expansion coefficient, low glass density, and devitrification prevention characteristics during production of sheet glass.

本発明の一側面としては、下記酸化物基準の質量百分率表示で、
ＳｉＯ２を６０％超過、
ＺｒＯ２を０．５〜５％、
Ｎａ２Ｏを４〜８％、
Ａｌ２Ｏ３、ＭｇＯ、ＣａＯを含み、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯを１３．１％以下、
Ｎａ２Ｏ+Ｋ２Ｏを１２．５％以下含有し、
ＳｉＯ２−Ａｌ２Ｏ３が４３％以上５０％未満であり、
Ｋ２Ｏ／Ｎａ２Ｏが１．３以下であり、
ガラス転移点温度が６４０℃以上、密度が２．７ｇ／ｃｍ３以下である、ガラス基板を提供する。 As one aspect of the present invention, the mass percentage display based on the following oxide,
The SiO 2 60% excess,
ZrO 2 0.5-5%,
Na 2 O 4-8%,
Including Al 2 O 3 , MgO, CaO,
MgO + CaO + SrO + BaO is 13.1% or less,
Na 2 O + K 2 O is contained at 12.5% or less,
SiO 2 —Al 2 O 3 is 43% or more and less than 50%,
K 2 O / Na 2 O is 1.3 or less,
A glass substrate having a glass transition temperature of 640 ° C. or higher and a density of 2.7 g / cm 3 or lower is provided.

本発明のガラス基板は、高い発電効率、高いガラス転移点温度、所定の平均熱膨張係数、低いガラス密度、及び板ガラス生産時の失透防止の特性をバランスよく有することができ、本発明のガラス基板を用いることで発電効率の高い太陽電池を提供できる。   The glass substrate of the present invention can have a good balance of high power generation efficiency, high glass transition temperature, predetermined average thermal expansion coefficient, low glass density, and devitrification prevention characteristics during production of plate glass. By using the substrate, a solar cell with high power generation efficiency can be provided.

図１は本発明のＣＩＧＳ太陽電池用ガラス基板を用いた太陽電池の実施形態の一例を模式的に表す断面図である。FIG. 1 is a cross-sectional view schematically illustrating an example of an embodiment of a solar cell using the CIGS solar cell glass substrate of the present invention. 図２Ａは、実施例において評価用ガラス基板上に作製した太陽電池セルを示す。FIG. 2A shows a solar battery cell produced on a glass substrate for evaluation in the examples. 図２Ｂは、図２Ａに示した太陽電池セルのＡ−Ａ’線に沿った断面図を示す。FIG. 2B shows a cross-sectional view along the line A-A ′ of the solar battery cell shown in FIG. 2A. 図３は、図２Ａに示す太陽電池セルを８個並べた、評価用ガラス基板上の評価用ＣＩＧＳ太陽電池を示す。FIG. 3 shows a CIGS solar cell for evaluation on a glass substrate for evaluation in which eight solar cells shown in FIG. 2A are arranged.

＜本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板＞
以下、本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板について説明する。
本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板は、下記酸化物基準の質量百分率表示で、
ＳｉＯ２を５６〜６３％、
Ａｌ２Ｏ３を１０〜１５％、
Ｂ２Ｏ３を０〜１％、
ＭｇＯを２．５〜５％、
ＣａＯを３〜８％、
ＳｒＯを０〜４％、
ＢａＯを０〜５％、
ＺｒＯ２を０．５〜５％、
ＴｉＯ２を０〜３％、
Ｌａ２Ｏ３を０〜５％、
Ｎａ２Ｏを４〜８％、
Ｋ２Ｏを３〜８％、
Ｎａ２Ｏ+Ｋ２Ｏを１０〜１５％含有し、
ＳｉＯ２−Ａｌ２Ｏ３が４３％以上５０％未満であり、
Ｋ２Ｏ／Ｎａ２Ｏが１．３以下であり、
ガラス転移点温度が６４０℃以上、平均熱膨張係数が７０×１０−７〜９０×１０−７／℃、密度が２．７ｇ／ｃｍ３以下であるＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板である。
なお、Ｃｕ−Ｉｎ−Ｇａ−Ｓｅを以下「ＣＩＧＳ」と記載する。 <The glass substrate for Cu-In-Ga-Se solar cells of this invention>
Hereinafter, the glass substrate for a Cu—In—Ga—Se solar cell of the present invention will be described.
The glass substrate for a Cu-In-Ga-Se solar cell of the present invention is a mass percentage display based on the following oxide,
The SiO 2 56~63%,
Al 2 O 3 10-15%,
B 2 O 3 0 to 1%
MgO 2.5-5%,
3-8% CaO,
0-4% SrO,
BaO 0-5%,
ZrO 2 0.5-5%,
0 to 3% of TiO 2
La 2 O 3 0-5%,
Na 2 O 4-8%,
3 to 8% of K 2 O,
Containing 10-15% Na 2 O + K 2 O,
SiO 2 —Al 2 O 3 is 43% or more and less than 50%,
K 2 O / Na 2 O is 1.3 or less,
Glass for Cu—In—Ga—Se solar cells having a glass transition temperature of 640 ° C. or higher, an average coefficient of thermal expansion of 70 × 10 −7 to 90 × 10 −7 / ° C., and a density of 2.7 g / cm 3 or less. It is a substrate.
Note that Cu—In—Ga—Se is hereinafter referred to as “CIGS”.

本発明のＣＩＧＳ太陽電池用ガラス基板のガラス転移点温度（Ｔｇ）は６４０℃以上であり、ソーダライムガラスのガラス転移点温度より高い。ガラス転移点温度（Ｔｇ）は、高温におけるＣＩＧＳ層の形成を担保するため６５０℃以上であるのが好ましく、６５５℃以上がより好ましく、６６０℃以上がさらに好ましい。一方、ガラス転移点温度（Ｔｇ）は、溶解時の粘性を上げ過ぎないようにするために７５０℃以下とするのが好ましい。
ガラス転移点温度（Ｔｇ）は、より好ましくは７２０℃以下、さらに好ましくは６９０℃以下である。 The glass transition point temperature (T g ) of the glass substrate for CIGS solar cell of the present invention is 640 ° C. or higher, which is higher than the glass transition temperature of soda lime glass. The glass transition temperature (T g ) is preferably 650 ° C. or higher, more preferably 655 ° C. or higher, and further preferably 660 ° C. or higher in order to ensure the formation of the CIGS layer at a high temperature. On the other hand, the glass transition temperature (T g ) is preferably 750 ° C. or lower so as not to increase the viscosity at the time of melting.
The glass transition temperature (T g ) is more preferably 720 ° C. or lower, and further preferably 690 ° C. or lower.

本発明のＣＩＧＳ太陽電池用ガラス基板の５０〜３５０℃における平均熱膨張係数は７０×１０−７〜９０×１０−７／℃である。当該平均熱膨張係数が７０×１０−７／℃未満または９０×１０−７／℃超では、ＣＩＧＳ層との熱膨張差が大きくなりすぎ、剥がれ等の欠点が生じやすくなる。当該平均熱膨張係数は、好ましくは８５×１０−７／℃以下である。 The average thermal expansion coefficient at 50 to 350 ° C. of the glass substrate for CIGS solar cell of the present invention is 70 × 10 −7 to 90 × 10 −7 / ° C. If the average coefficient of thermal expansion is less than 70 × 10 −7 / ° C. or more than 90 × 10 −7 / ° C., the difference in thermal expansion from the CIGS layer becomes too large, and defects such as peeling tend to occur. The average thermal expansion coefficient is preferably 85 × 10 −7 / ° C. or less.

本発明のＣＩＧＳ太陽電池用ガラス基板は、粘度が１０４ｄＰａ・ｓとなる温度（Ｔ４）と失透温度（ＴＬ）との関係がＴ４−ＴＬ≧−３０℃であることが好ましい。Ｔ４−ＴＬが−３０℃未満では、板ガラス成形時に失透が生じやすく、ガラス板の成形が困難になるおそれがある。Ｔ４−ＴＬは、より好ましくは−２０℃以上、さらに好ましくは−１０℃以上、特に好ましくは０℃以上、より特に好ましくは１０℃以上である。ここで、失透温度とは、ガラスを特定の温度で１７時間保持するときに、ガラス表面および内部に結晶が生成しない最大温度を指す。
ガラス板の成形性、即ち、平坦性向上や生産性向上を考慮すると、Ｔ４は１２５０℃以下であることが好ましい。Ｔ４は１２３０℃以下がより好ましく、１２１０℃以下がさらに好ましい。 In the glass substrate for CIGS solar cell of the present invention, the relationship between the temperature (T 4 ) at which the viscosity is 10 4 dPa · s and the devitrification temperature (T L ) is T 4 −T L ≧ −30 ° C. preferable. T 4 The -T L is lower than -30 ° C., devitrification is likely to occur at the time of sheet glass forming, there is a possibility that the molding of the glass plate becomes difficult. T 4 -T L is more preferably -20 ° C. or higher, more preferably -10 ° C. or higher, particularly preferably 0 ℃ or more, more particularly preferably at 10 ° C. or higher. Here, the devitrification temperature refers to the maximum temperature at which crystals are not generated on the glass surface and inside when the glass is held at a specific temperature for 17 hours.
In consideration of moldability of the glass plate, that is, improvement in flatness and productivity, T 4 is preferably 1250 ° C. or less. T 4 is more preferably 1230 ° C. or less, and further preferably 1210 ° C. or less.

また、本発明のＣＩＧＳ太陽電池用ガラス基板は、ガラスの溶解性、即ち、均質性向上や生産性向上を考慮して、粘度が１０２ｄＰａ・ｓとなる温度（Ｔ２）を１７００℃以下とすることが好ましい。Ｔ２は１６５０℃以下がより好ましく、１６３０℃以下がさらに好ましい。 In addition, the glass substrate for CIGS solar cell of the present invention has a temperature (T 2 ) at which the viscosity becomes 10 2 dPa · s at 1700 ° C. or less in consideration of glass solubility, that is, improvement in homogeneity and productivity. It is preferable that T 2 is more preferably 1650 ° C. or less, and further preferably 1630 ° C. or less.

本発明のＣＩＧＳ太陽電池用ガラス基板は、密度が２．７ｇ／ｃｍ３以下である。密度が２．７ｇ／ｃｍ３を超えると、製品質量が重くなり好ましくない。密度は好ましくは２．６５ｇ／ｃｍ３以下、より好ましくは２．６ｇ／ｃｍ３以下である。また、密度は、フロート法やフュージョン法等の通常の方法でガラス基板を製造するために、容易に製造可能なガラス組成範囲であることを考慮すると、２．４ｇ／ｃｍ３以上であることが好ましい。 The glass substrate for CIGS solar cell of the present invention has a density of 2.7 g / cm 3 or less. When the density exceeds 2.7 g / cm 3 , the product mass becomes heavy, which is not preferable. The density is preferably 2.65 g / cm 3 or less, more preferably 2.6 g / cm 3 or less. Further, the density is 2.4 g / cm 3 or more in consideration of the glass composition range that can be easily manufactured in order to manufacture a glass substrate by a normal method such as a float method or a fusion method. preferable.

本発明のＣＩＧＳ太陽電池用ガラス基板において上記組成に限定する理由は以下のとおりである。
なお、以下における百分率（％）は、特に断りがない限り、質量％を意味するものとする。
また、本発明において「実質的に含有しない」とは、原料等から混入する不可避的不純物以外には含有しないこと、すなわち、意図的に含有させないことを意味し、これ以降、特に断りがなければ、具体的には、含有量が０．１％以下であることとする。
ＳｉＯ２：ＳｉＯ２はガラスの骨格を形成する成分で、その含有量が５６％未満ではガラス基板の耐熱性および化学的耐久性が低下し、平均熱膨張係数が増大するおそれがある。その含有量は、好ましくは５８％以上であり、より好ましくは６０％以上である。
しかし、その含有量が６３％超であると、ガラスの高温粘度が上昇し、溶解性が悪化する問題が生じるおそれがある。その含有量は、好ましくは６２％以下である。 The reason for limiting to the said composition in the glass substrate for CIGS solar cells of this invention is as follows.
In addition, the percentage (%) in the following shall mean the mass% unless there is particular notice.
Further, in the present invention, “substantially does not contain” means that it is not contained other than unavoidable impurities mixed from raw materials or the like, that is, it is not intentionally contained, and thereafter, unless otherwise noted. Specifically, the content is 0.1% or less.
SiO 2 : SiO 2 is a component that forms a glass skeleton, and if its content is less than 56%, the heat resistance and chemical durability of the glass substrate may decrease, and the average thermal expansion coefficient may increase. The content is preferably 58% or more, more preferably 60% or more.
However, when the content is more than 63%, the high temperature viscosity of the glass is increased, which may cause a problem that the solubility is deteriorated. Its content is preferably 62% or less.

Ａｌ２Ｏ３：Ａｌ２Ｏ３はガラス転移点温度を上げ、耐候性（ソラリゼーション）、耐熱性および化学的耐久性を向上させる。その含有量が１０％未満では、ガラス転移点温度が低下するおそれがある。また平均熱膨張係数が増大するおそれがある。その含有量は、好ましくは１０．５％以上であり、より好ましくは１１％以上である。
しかし、その含有量が１５％超であると、ガラスの高温粘度が上昇し、溶解性が悪くなるおそれがある。
また、失透温度が上昇し、成形性が悪くなるおそれがある。また発電効率が低下するおそれがある。その含有量は、好ましくは１３％以下である。 Al 2 O 3 : Al 2 O 3 raises the glass transition temperature and improves weather resistance (solarization), heat resistance and chemical durability. If the content is less than 10%, the glass transition temperature may be lowered. Moreover, there exists a possibility that an average thermal expansion coefficient may increase. The content is preferably 10.5% or more, more preferably 11% or more.
However, if the content exceeds 15%, the high-temperature viscosity of the glass is increased, and the solubility may be deteriorated.
Further, the devitrification temperature is increased, and the moldability may be deteriorated. In addition, power generation efficiency may be reduced. Its content is preferably 13% or less.

Ｂ２Ｏ３：Ｂ２Ｏ３は、溶解性を向上させる等のために１％まで含有してもよい。その含有量が１％を超えると、ガラス転移点温度が下がる、または平均熱膨張係数が小さくなる傾向があり、ＣＩＧＳ層を形成するプロセスにとって好ましくない。また失透温度が上昇して失透しやすくなり、板ガラス成形が難しくなる。その含有量は、好ましくは０．５％以下である。Ｂ２Ｏ３を実質的に含有しないことがより好ましい。 B 2 O 3 : B 2 O 3 may be contained up to 1% in order to improve the solubility. If the content exceeds 1%, the glass transition temperature tends to decrease or the average thermal expansion coefficient tends to decrease, which is not preferable for the process of forming the CIGS layer. Moreover, devitrification temperature rises and it becomes easy to devitrify, and plate glass shaping | molding becomes difficult. Its content is preferably 0.5% or less. More preferably, B 2 O 3 is not substantially contained.

ＭｇＯ：ＭｇＯはガラスの溶解時の粘性を下げ、溶解を促進する効果があるので含有させるが、その含有量が２．５％未満であると、ガラスの高温粘度が上昇し溶解性が悪化するおそれがある。また、化学的耐久性が悪くなり、密度が増大するおそれがある。その含有量は、好ましくは３％以上である。
しかし、その含有量が５％超であると、発電効率が低下するおそれがある。また失透温度が上昇するおそれがある。その含有量は、好ましくは５％以下、より好ましくは４．５％以下である。 MgO: MgO is contained because it has the effect of lowering the viscosity at the time of melting the glass and promoting the melting, but if its content is less than 2.5%, the high temperature viscosity of the glass is increased and the solubility is deteriorated. There is a fear. Moreover, chemical durability may deteriorate and density may increase. The content is preferably 3% or more.
However, if the content exceeds 5%, the power generation efficiency may decrease. Further, the devitrification temperature may increase. The content is preferably 5% or less, more preferably 4.5% or less.

ＣａＯ：ＣａＯはガラスの溶解時の粘性を下げ、溶解を促進する効果があるので含有させるが、その含有量が３％未満では、ガラスの高温粘度が上昇し溶解性が悪化するおそれがある。その含有量は、好ましくは３％以上、より好ましくは４％以上である。しかし、その含有量が８％超であると、ガラスの平均熱膨張係数が増大するおそれがある。また、Ｎａがガラス基板中で移動しにくくなり発電効率が低下するおそれがある。その含有量は、好ましくは６％以下である。   CaO: CaO is contained because it has the effect of lowering the viscosity at the time of melting the glass and promoting the melting. However, if its content is less than 3%, the high-temperature viscosity of the glass may increase and the solubility may deteriorate. The content is preferably 3% or more, more preferably 4% or more. However, if the content exceeds 8%, the average thermal expansion coefficient of the glass may increase. In addition, Na is less likely to move in the glass substrate, which may reduce power generation efficiency. Its content is preferably 6% or less.

ＳｒＯ：ＳｒＯはガラスの溶解時の粘性を下げ、溶解を促進する効果があるので含有させることができる。しかし、ＳｒＯを４％超含有すると、発電効率が低下し、また、ガラス基板の平均熱膨張係数が増大し、密度が増大するおそれがある。その含有量は、３％以下が好ましく、２％以下であることがより好ましい。   SrO: SrO can be contained because it has the effect of lowering the viscosity at the time of melting the glass and promoting the melting. However, when SrO exceeds 4%, the power generation efficiency decreases, the average thermal expansion coefficient of the glass substrate increases, and the density may increase. The content is preferably 3% or less, and more preferably 2% or less.

ＢａＯ：ＢａＯはガラスの溶解時の粘性を下げ、溶解を促進する効果があるので含有させることができる。しかし、ＢａＯを５％超含有すると、ガラス基板の平均熱膨張係数が増大し、また密度が増大するおそれがある。その含有量は、５％以下が好ましく、４％以下であることがより好ましい。   BaO: BaO can be contained because it has the effect of lowering the viscosity at the time of melting the glass and promoting the melting. However, when BaO exceeds 5%, the average thermal expansion coefficient of the glass substrate increases and the density may increase. The content is preferably 5% or less, and more preferably 4% or less.

ＺｒＯ２：ＺｒＯ２はガラスの溶解時の粘性を下げ、溶解を促進する効果があり、また耐熱性および化学的耐久性を向上させるので含有させるが、その含有量が０．５％未満では、ガラス転移点温度が低下するおそれがある。その含有量は、好ましくは０．５％以上であり、より好ましくは１％以上である。しかし、ＺｒＯ２を５％超含有すると失透温度が上昇して失透しやすくなり板ガラス成形が難しくなる。または、密度が増大するおそれがある。その含有量は、好ましくは４．５％以下であり、より好ましくは３％以下である。 ZrO 2 : ZrO 2 has the effect of lowering the viscosity at the time of melting the glass and promoting the melting, and also improves the heat resistance and chemical durability. However, if the content is less than 0.5%, The glass transition temperature may be lowered. The content is preferably 0.5% or more, more preferably 1% or more. However, if the ZrO 2 content exceeds 5%, the devitrification temperature rises and the glass tends to be devitrified, making it difficult to form a sheet glass. Or, the density may increase. The content is preferably 4.5% or less, more preferably 3% or less.

ＴｉＯ２：ＴｉＯ２は溶解性の向上等のために３％まで含有してもよい。その含有量が３％を超えると、失透温度が上昇して失透しやすくなり板ガラス成形が難しくなる。その含有量は、好ましくは２％以下であり、より好ましくは１％以下である。 TiO 2 : TiO 2 may be contained up to 3% in order to improve solubility. If the content exceeds 3%, the devitrification temperature rises and the glass tends to be devitrified, making it difficult to form a glass sheet. The content is preferably 2% or less, more preferably 1% or less.

Ｌａ２Ｏ３：Ｌａ２Ｏ３はガラスの溶解時の粘性を下げ、溶解を促進する効果があるので含有させることができる。また、耐熱性および化学的耐久性を向上させる。その含有量が５％を超えると、失透温度が上昇して失透しやすくなり板ガラス成形が難しくなる。また、Ｌａ２Ｏ３の原料はコストを増大させるおそれがある。Ｌａ２Ｏ３の含有量は、４％以下が好ましく、特にガラスの溶解時の粘性が十分低く、かつ耐熱性が要求される目的以外では、Ｌａ２Ｏ３は実質的に含有されないことが好ましい。 La 2 O 3 : La 2 O 3 can be contained because it has an effect of reducing the viscosity at the time of melting the glass and promoting the melting. It also improves heat resistance and chemical durability. If the content exceeds 5%, the devitrification temperature rises and the glass tends to be devitrified, making it difficult to form a glass sheet. Further, the raw material of La 2 O 3, there is a possibility of increasing the cost. The content of La 2 O 3 is preferably 4% or less, and it is preferable that La 2 O 3 is not substantially contained except for the purpose that the viscosity at the time of melting of glass is sufficiently low and heat resistance is required. .

Ｎａ２Ｏ：Ｎａ２ＯはＣＩＧＳの太陽電池の発電効率向上に寄与するための成分であり、必須成分である。また、ガラス溶解温度での粘性を下げ、溶解しやすくする効果があるので４〜８％含有させる。Ｎａはガラス基板上に構成されたＣＩＧＳ層中に拡散し、発電効率を高めるが、Ｎａ２Ｏの含有量が４％未満では、ガラス基板上のＣＩＧＳ層へのＮａ拡散が不十分となり、発電効率も不十分となるおそれがある。その含有量が４．５％以上であると好ましく、５％以上であるとより好ましい。
Ｎａ２Ｏの含有量が８％を超えると、平均熱膨張係数が大きくなり、ガラス転移点温度が低下する傾向がある。または化学的耐久性が劣化する傾向がある。その含有量は、７．５％以下であると好ましく、７％以下であるとより好ましい。 Na 2 O: Na 2 O is a component that contributes to improving the power generation efficiency of CIGS solar cells, and is an essential component. Moreover, since there exists an effect which lowers | hangs the viscosity in glass melting temperature and makes it easy to melt | dissolve, it contains 4 to 8%. Na diffuses into the CIGS layer formed on the glass substrate to increase the power generation efficiency. However, if the Na 2 O content is less than 4%, Na diffusion to the CIGS layer on the glass substrate becomes insufficient, resulting in power generation. The efficiency may also be insufficient. The content is preferably 4.5% or more, more preferably 5% or more.
When the content of Na 2 O exceeds 8%, the average thermal expansion coefficient tends to increase and the glass transition temperature tends to decrease. Or chemical durability tends to deteriorate. The content is preferably 7.5% or less, and more preferably 7% or less.

Ｋ２Ｏ：Ｋ２ＯはＮａ２Ｏと同様の効果があるため、３〜８％含有させる。その含有量が３％未満では、ガラス基板上のＣＩＧＳ層へのＫ拡散が不十分となり、発電効率も不十分となるおそれがある。その含有量は３％以上であると好ましく、４％以上であるとより好ましい。
しかし、その含有量が８％超であると、ガラス転移点温度が低下し、平均熱膨張係数が大きくなるおそれがある。または、密度が増大するおそれがある。その含有量は６％以下であることが好ましく、５％以下であることがより好ましい。 K 2 O: K 2 O is due to the same effect as Na 2 O, is contained 3-8%. If the content is less than 3%, K diffusion to the CIGS layer on the glass substrate may be insufficient, and power generation efficiency may be insufficient. The content is preferably 3% or more, and more preferably 4% or more.
However, if the content is more than 8%, the glass transition temperature may be lowered and the average thermal expansion coefficient may be increased. Or, the density may increase. The content is preferably 6% or less, and more preferably 5% or less.

Ｎａ２ＯおよびＫ２Ｏ：ガラス溶解温度での粘性を十分に下げるために、またＣＩＧＳ太陽電池の発電効率向上のために、Ｎａ２ＯおよびＫ２Ｏの合量（Ｎａ２Ｏ＋Ｋ２Ｏ）は１０〜１５％であり、好ましくは１０．５％以上であり、より好ましくは１１％以上である。しかし、Ｎａ２Ｏ＋Ｋ２Ｏが１５％超であると、ガラス転移点温度が下がりすぎるおそれがある。Ｎａ２Ｏ＋Ｋ２Ｏは、１３％以下が好ましく、１２．５％以下であることがより好ましい。 Na 2 O and K 2 O: The total amount of Na 2 O and K 2 O (Na 2 O + K 2 O) in order to sufficiently reduce the viscosity at the glass melting temperature and to improve the power generation efficiency of the CIGS solar cell Is 10 to 15%, preferably 10.5% or more, more preferably 11% or more. However, if Na 2 O + K 2 O exceeds 15%, the glass transition temperature may be too low. Na 2 O + K 2 O is preferably 13% or less, and more preferably 12.5% or less.

また、Ｎａ２Ｏ量とＫ２Ｏ量の比（Ｋ２Ｏ／Ｎａ２Ｏ）は１．３以下である。Ｎａ２Ｏ量がＫ２Ｏ量に対して少ないと、ガラス上のＣＩＧＳ層へのＮａ拡散が不十分となり、発電効率も不十分となるおそれがある。Ｋ２Ｏ／Ｎａ２Ｏは、好ましくは１．２５以下、より好ましくは１．２以下、さらに好ましくは１．１以下、特に好ましくは１．０以下である。しかし、ガラス基板上のＣＩＧＳ層へのＫ拡散を確保し発電効率を確保する観点から、Ｋ２Ｏ／Ｎａ２Ｏは、０．４以上であることが好ましく、より好ましくは０．５以上、さらに好ましくは０．６以上、特に好ましくは０．７以上である。 The ratio of Na 2 O weight and K 2 O amount (K 2 O / Na 2 O ) is 1.3 or less. When the amount of Na 2 O is smaller than the amount of K 2 O, Na diffusion to the CIGS layer on the glass becomes insufficient, and the power generation efficiency may be insufficient. K 2 O / Na 2 O is preferably 1.25 or less, more preferably 1.2 or less, still more preferably 1.1 or less, and particularly preferably 1.0 or less. However, from the viewpoint of ensuring K diffusion to the CIGS layer on the glass substrate and ensuring power generation efficiency, K 2 O / Na 2 O is preferably 0.4 or more, more preferably 0.5 or more. More preferably, it is 0.6 or more, and particularly preferably 0.7 or more.

ＳｉＯ２およびＡｌ２Ｏ３：上記Ｎａ２ＯおよびＫ２Ｏの条件を満たした上でガラス転移点温度（Ｔｇ）を６４０℃以上にするためには、ＳｉＯ２量からＡｌ２Ｏ３量を引いた値（ＳｉＯ２−Ａｌ２Ｏ３）は４３％以上５０％未満である。ＳｉＯ２−Ａｌ２Ｏ３が５０％以上ではガラス転移点温度が下がりすぎるおそれがある。ＳｉＯ２−Ａｌ２Ｏ３は、好ましくは４９．５％以下、より好ましくは４９％以下である。しかし、ＳｉＯ２−Ａｌ２Ｏ３が４３％未満ではガラスの高温粘度が上昇し、溶解性が悪くなるおそれがある。また、失透温度が上昇し、成形性が悪くなるおそれがある。さらにＮａおよびＫの拡散量が抑制され、発電効率が不十分になるおそれがある。ＳｉＯ２−Ａｌ２Ｏ３は、好ましくは４５％以上であり、より好ましくは４７％以上である。 SiO 2 and Al 2 O 3 : In order to make the glass transition temperature (T g ) 640 ° C. or higher after satisfying the above conditions of Na 2 O and K 2 O, the amount of Al 2 O 3 is changed from the amount of SiO 2 . The value obtained by subtracting (SiO 2 —Al 2 O 3 ) is 43% or more and less than 50%. If SiO 2 —Al 2 O 3 is 50% or more, the glass transition temperature may be too low. SiO 2 —Al 2 O 3 is preferably 49.5% or less, more preferably 49% or less. However, if SiO 2 —Al 2 O 3 is less than 43%, the high-temperature viscosity of the glass is increased, and the solubility may be deteriorated. Further, the devitrification temperature is increased, and the moldability may be deteriorated. Furthermore, the diffusion amount of Na and K is suppressed, and the power generation efficiency may be insufficient. SiO 2 -Al 2 O 3 is preferably 45% or more, and more preferably at least 47%.

本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板は、下記酸化物基準の質量百分率表示で、
ＳｉＯ２を５８〜６２％、
Ａｌ２Ｏ３を１０〜１３％、
Ｂ２Ｏ３を０〜０．５％、
ＭｇＯを３〜４．５％、
ＣａＯを４〜６％、
ＳｒＯを０〜３％、
ＢａＯを０〜４％、
ＺｒＯ２を０．５〜３％、
ＴｉＯ２を０〜３％、
Ｌａ２Ｏ３を０〜４％、
Ｎａ２Ｏを５〜７％、
Ｋ２Ｏを３〜６％、
Ｎａ２Ｏ+Ｋ２Ｏを１０〜１３％含有し、
ＳｉＯ２−Ａｌ２Ｏ３が４３％以上５０％未満であり、
Ｋ２Ｏ／Ｎａ２Ｏが１．２以下であり、
ガラス転移点温度が６５０℃以上、平均熱膨張係数が７０×１０−７〜９０×１０−７／℃、密度が２．７ｇ／ｃｍ３以下であるＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板が好ましい。 The glass substrate for a Cu-In-Ga-Se solar cell of the present invention is a mass percentage display based on the following oxide,
The SiO 2 58~62%,
Al 2 O 3 10-13%
B 2 O 3 0 to 0.5%
3 to 4.5% MgO,
4-6% CaO,
0 to 3% of SrO,
BaO 0-4%,
ZrO 2 0.5-3%,
0 to 3% of TiO 2
La 2 O 3 0-4%,
The Na 2 O 5~7%,
3 to 6% of K 2 O,
Containing 10-13% Na 2 O + K 2 O,
SiO 2 —Al 2 O 3 is 43% or more and less than 50%,
K 2 O / Na 2 O is 1.2 or less,
Glass for Cu—In—Ga—Se solar cells having a glass transition temperature of 650 ° C. or higher, an average coefficient of thermal expansion of 70 × 10 −7 to 90 × 10 −7 / ° C., and a density of 2.7 g / cm 3 or less. A substrate is preferred.

本発明のＣＩＧＳ太陽電池用ガラス基板は本質的に上記母組成からなるが、本発明の目的を損なわない範囲でその他の成分を、それぞれ１％以下、合計で５％以下含有してもよい。たとえば、耐候性、溶解性、失透性、紫外線遮蔽、屈折率等の改善を目的に、ＺｎＯ、Ｌｉ２Ｏ、ＷＯ３、Ｎｂ２Ｏ５、Ｖ２Ｏ５、Ｂｉ２Ｏ３、ＭｏＯ３、ＴｉＯ２、Ｐ２Ｏ５等を含有してもよい場合がある。 The glass substrate for CIGS solar cell of the present invention consists essentially of the above mother composition, but may contain other components in an amount of 1% or less and a total of 5% or less in a range not impairing the object of the present invention. For example, ZnO, Li 2 O, WO 3 , Nb 2 O 5 , V 2 O 5 , Bi 2 O 3 , MoO 3 for the purpose of improving weather resistance, solubility, devitrification, ultraviolet shielding, refractive index, and the like. , TiO 2 , P 2 O 5 and the like may be contained.

また、ガラスの溶解性や清澄性を改善するため、ガラス基板中にＳＯ３、Ｆ、Ｃｌ及び／又はＳｎＯ２をそれぞれ１％以下、合量で２％以下含有するように、これらの原料を母組成原料に添加してもよい。
また、ガラス基板の化学的耐久性向上のため、ガラス基板中にＹ２Ｏ３及び／又はＬａ２Ｏ３を合量で２％以下含有させてもよい。 In order to improve the solubility and clarity of the glass, these raw materials are added so that each glass substrate contains SO 3 , F, Cl and / or SnO 2 in an amount of 1% or less and a total amount of 2% or less. You may add to a mother composition raw material.
Further, in order to improve the chemical durability of the glass substrate, Y 2 O 3 and / or La 2 O 3 may be contained in the glass substrate in a total amount of 2% or less.

また、ガラス基板の色調を調整するため、ガラス基板中にＦｅ２Ｏ３等の着色剤を含有してもよい。このような着色剤の含有量は、合量で１％以下が好ましい。
また、本発明のＣＩＧＳ太陽電池用ガラス基板は、環境負荷を考慮すると、Ａｓ２Ｏ３及びＳｂ２Ｏ３を実質的に含有しないことが好ましい。また、安定してフロート成形することを考慮すると、ＺｎＯを実質的に含有しないことが好ましい。しかし、本発明のＣＩＧＳ太陽電池用ガラス基板は、フロート法による成形に限らず、フュージョン法による成形により製造してもよい。 Further, in order to adjust the color tone of the glass substrate, it may contain a colorant such as Fe 2 O 3 in the glass substrate. The total content of such colorants is preferably 1% or less.
Further, the glass substrate for a CIGS solar cell of the present invention, considering the environmental burden, it is preferred that free of As 2 O 3 and Sb 2 O 3 substantially. In consideration of stable float forming, it is preferable that ZnO is not substantially contained. However, the glass substrate for CIGS solar cell of the present invention is not limited to being formed by the float method, and may be manufactured by forming by the fusion method.

＜本発明のＣＩＧＳ太陽電池用ガラス基板の製造方法＞
本発明のＣＩＧＳ太陽電池用ガラス基板の製造方法について説明する。
本発明のＣＩＧＳ太陽電池用ガラス基板を製造する場合、従来の太陽電池用ガラス基板を製造する際と同様に、溶解・清澄工程および成形工程を実施する。なお、本発明のＣＩＧＳ太陽電池用ガラス基板は、アルカリ金属酸化物（Ｎａ２Ｏ及びＫ２Ｏ）を含有するアルカリガラス基板であるため、清澄剤としてＳＯ３を効果的に用いることができ、成形方法としてフロート法およびフュージョン法（ダウンドロー法）に適している。
太陽電池用のガラス基板の製造工程において、ガラスを板状に成形する方法としては、太陽電池の大型化に伴い、大面積のガラス基板を容易に、安定して成形できるフロート法を用いることが好ましい。 <The manufacturing method of the glass substrate for CIGS solar cells of this invention>
The manufacturing method of the glass substrate for CIGS solar cells of this invention is demonstrated.
When manufacturing the glass substrate for CIGS solar cells of this invention, a melt | dissolution and clarification process and a shaping | molding process are implemented similarly to the time of manufacturing the conventional glass substrate for solar cells. In addition, since the glass substrate for CIGS solar cells of the present invention is an alkali glass substrate containing alkali metal oxides (Na 2 O and K 2 O), SO 3 can be effectively used as a fining agent, Suitable for the float method and fusion method (down draw method) as the molding method.
In the manufacturing process of a glass substrate for a solar cell, as a method for forming glass into a plate shape, a float method capable of easily and stably forming a large-area glass substrate with the enlargement of the solar cell is used. preferable.

本発明のＣＩＧＳ太陽電池用ガラス基板の製造方法の好ましい態様について説明する。
初めに、原料を溶解して得た溶融ガラスを板状に成形する。例えば、得られるガラス基板が上記組成となるように原料を調製し、上記原料を溶解炉に連続的に投入し、１５５０〜１７００℃に加熱して溶融ガラスを得る。そしてこの溶融ガラスを例えばフロート法を適用してリボン状のガラス板に成形する。
次に、リボン状のガラス板をフロート成形炉から引出した後に、冷却手段によって室温状態まで冷却し、切断後、ＣＩＧＳ太陽電池用ガラス基板を得る。 The preferable aspect of the manufacturing method of the glass substrate for CIGS solar cells of this invention is demonstrated.
First, molten glass obtained by melting raw materials is formed into a plate shape. For example, raw materials are prepared so that the obtained glass substrate has the above composition, the raw materials are continuously charged into a melting furnace, and heated to 1550 to 1700 ° C. to obtain molten glass. The molten glass is formed into a ribbon-like glass plate by applying, for example, a float process.
Next, after pulling out the ribbon-shaped glass plate from the float forming furnace, it is cooled to room temperature by a cooling means, and after cutting, a CIGS solar cell glass substrate is obtained.

＜本発明のＣＩＧＳ太陽電池用ガラス基板の用途＞
本発明のＣＩＧＳ太陽電池用ガラス基板は、ＣＩＧＳ太陽電池用のガラス基板、またカバーガラスとしても好適である。
本発明のＣＩＧＳ太陽電池用ガラス基板をガラス基板に適用する場合、ガラス基板の厚さは３ｍｍ以下とするのが好ましく、より好ましくは２ｍｍ以下、さらに好ましくは１．５ｍｍ以下である。またガラス基板にＣＩＧＳ層を付与する方法は特に制限されない。本発明のＣＩＧＳ太陽電池用ガラス基板を用いることで、ＣＩＧＳ層を形成する際の加熱温度を５００〜７００℃、好ましくは５７０〜７００℃とすることができる。
本発明のＣＩＧＳ太陽電池用ガラス基板をガラス基板のみに使用する場合、カバーガラス等は特に制限されない。カバーガラスの組成の他の例は、ソーダライムガラス等が挙げられる。 <Application of CIGS Solar Cell Glass Substrate of the Present Invention>
The glass substrate for CIGS solar cells of the present invention is also suitable as a glass substrate for CIGS solar cells and a cover glass.
When applying the glass substrate for CIGS solar cells of this invention to a glass substrate, it is preferable that the thickness of a glass substrate shall be 3 mm or less, More preferably, it is 2 mm or less, More preferably, it is 1.5 mm or less. Moreover, the method in particular of providing a CIGS layer to a glass substrate is not restrict | limited. By using the glass substrate for CIGS solar cell of the present invention, the heating temperature when forming the CIGS layer can be 500 to 700 ° C, preferably 570 to 700 ° C.
When using the glass substrate for CIGS solar cells of this invention only for a glass substrate, a cover glass etc. are not restrict | limited in particular. Other examples of the composition of the cover glass include soda lime glass.

本発明のＣＩＧＳ太陽電池用ガラス基板をカバーガラスとして使用する場合、カバーガラスの厚さは３ｍｍ以下とするのが好ましく、より好ましくは２ｍｍ以下、さらに好ましくは１．５ｍｍ以下である。またＣＩＧＳ層を有するガラス基板にカバーガラスを組立てる方法は特に制限されない。本発明のＣＩＧＳ太陽電池用ガラス基板を用いることで、加熱して組立てる場合、その加熱温度を５００〜７００℃、好ましくは５７０〜７００℃とすることができる。   When the glass substrate for CIGS solar cell of the present invention is used as a cover glass, the thickness of the cover glass is preferably 3 mm or less, more preferably 2 mm or less, and further preferably 1.5 mm or less. The method for assembling the cover glass on the glass substrate having the CIGS layer is not particularly limited. When heating and assembling by using the glass substrate for CIGS solar cell of this invention, the heating temperature can be 500-700 degreeC, Preferably it can be 570-700 degreeC.

本発明のＣＩＧＳ太陽電池用ガラス基板は、膨張係数がソーダライムガラスに近く、ガラス転移点が高いという特徴から、その他の太陽電池用の基板ガラス、またはカバーガラスに用いることも可能である。例えばＣＩＧＳ太陽電池と同様に、光電変換層形成の際に５００〜７００℃の加熱温度が必要なＣｄ−Ｔe系化合物の太陽電池やＣｕ−Ｚｎ−Ｓｎ−Ｓ系（ＳはＳｅまたはＳ）化合物の太陽電池の光電変換層を形成するガラス基板に好適に利用される。   The CIGS solar cell glass substrate of the present invention can be used for other solar cell substrate glasses or cover glasses because of its characteristics that its expansion coefficient is close to that of soda lime glass and its glass transition point is high. For example, as with CIGS solar cells, Cd—Te compound solar cells and Cu—Zn—Sn—S (S is Se or S) compounds that require a heating temperature of 500 to 700 ° C. when forming the photoelectric conversion layer. It is suitably used for a glass substrate that forms a photoelectric conversion layer of a solar cell.

本発明のＣＩＧＳ太陽電池用ガラス基板をＣＩＧＳの太陽電池用のガラス基板およびカバーガラスに併用すると、平均熱膨張係数が同等であるため太陽電池組立時の熱変形等が発生せず好ましい。   When the CIGS solar cell glass substrate of the present invention is used in combination with a CIGS solar cell glass substrate and a cover glass, the average thermal expansion coefficient is equivalent, so that thermal deformation or the like during solar cell assembly does not occur.

＜本発明におけるＣＩＧＳ太陽電池＞
次に、本発明における太陽電池について説明する。
本発明における太陽電池は、ガラス基板と、カバーガラスと、上記ガラス基板と上記カバーガラスとの間に、光電変換層として配置されるＣＩＧＳ層と、を有する。そして、上記ガラス基板とカバーガラスとのうち少なくともガラス基板が、本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板である。 <CIGS solar cell in the present invention>
Next, the solar cell in this invention is demonstrated.
The solar cell in the present invention includes a glass substrate, a cover glass, and a CIGS layer disposed as a photoelectric conversion layer between the glass substrate and the cover glass. And at least a glass substrate is the glass substrate for Cu-In-Ga-Se solar cells of this invention among the said glass substrate and cover glasses.

以下添付の図面を使用して本発明における太陽電池を詳細に説明する。なお本発明は添付の図面に限定されない。
図１は本発明における太陽電池の実施形態の一例を模式的に表す断面図である。
図１において、本発明におけるＣＩＧＳ太陽電池１は、ガラス基板５、カバーガラス１９、およびガラス基板５とカバーガラス１９との間にＣＩＧＳ層９を有する。ガラス基板５は、上記で説明した本発明のＣＩＧＳ太陽電池用ガラス基板からなるのが好ましい。太陽電池１はガラス基板５上にプラス電極７であるＭｏ膜の裏面電極層を有し、その上にＣＩＧＳ層９を有する。ＣＩＧＳ層の組成はＣｕ（Ｉｎ１-ＸＧａｘ）Ｓｅ２が例示できる。ｘはＩｎとＧａの組成比を示すもので０＜ｘ＜１である。
ＣＩＧＳ層９上には、バッファ層１１としてのＣｄＳ（硫化カドミウム）層、ＺｎＳ（亜鉛硫化物）層、ＺｎＯ（酸化亜鉛）層、Ｚｎ（ＯＨ）２（水酸化亜鉛）層、またはこれらの混晶層を有する。バッファ層１１を介して、ＺｎＯまたはＩＴＯ、またはＡｌをドープしたＺｎＯ（ＡＺＯ）等の透明導電膜１３を有し、さらにその上にマイナス電極１５であるＡｌ電極（アルミニウム電極）等の取出し電極を有する。これらの層の間の必要な場所には反射防止膜を設けてもよい。図１においては、透明導電膜１３とマイナス電極１５との間に反射防止膜１７が設けられている。 Hereinafter, a solar cell in the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the attached drawings.
FIG. 1 is a cross-sectional view schematically showing an example of an embodiment of a solar cell in the present invention.
In FIG. 1, the CIGS solar cell 1 in the present invention has a glass substrate 5, a cover glass 19, and a CIGS layer 9 between the glass substrate 5 and the cover glass 19. It is preferable that the glass substrate 5 consists of the glass substrate for CIGS solar cells of this invention demonstrated above. The solar cell 1 has the back electrode layer of Mo film which is the plus electrode 7 on the glass substrate 5, and has the CIGS layer 9 on it. An example of the composition of the CIGS layer is Cu (In 1-X Ga x ) Se 2 . x represents the composition ratio of In and Ga, and 0 <x <1.
On the CIGS layer 9, a CdS (cadmium sulfide) layer, a ZnS (zinc sulfide) layer, a ZnO (zinc oxide) layer, a Zn (OH) 2 (zinc hydroxide) layer as a buffer layer 11, or a mixture thereof. It has a crystal layer. A transparent conductive film 13 such as ZnO, ITO, or Al doped ZnO (AZO) is provided through the buffer layer 11, and an extraction electrode such as an Al electrode (aluminum electrode) that is a negative electrode 15 is further provided thereon. Have. An antireflection film may be provided at a necessary place between these layers. In FIG. 1, an antireflection film 17 is provided between the transparent conductive film 13 and the negative electrode 15.

またマイナス電極１５上にカバーガラス１９を設けてもよく、必要な場合はマイナス電極とカバーガラスとの間は、樹脂封止したり接着用の透明樹脂で接着される。カバーガラスは、本発明のＣＩＧＳ太陽電池用ガラス基板を用いてもよい。
本発明においてＣＩＧＳ層の端部または太陽電池の端部は封止されていてもよい。封止するための材料としては、例えば本発明のＣＩＧＳ太陽電池用ガラス基板と同じ材料、そのほかのガラス、樹脂が挙げられる。
なお添付の図面に示す太陽電池の各層の厚さは図面に限定されない。 Further, a cover glass 19 may be provided on the minus electrode 15, and if necessary, the minus electrode and the cover glass are sealed with resin or bonded with a transparent resin for adhesion. As the cover glass, the glass substrate for CIGS solar cell of the present invention may be used.
In the present invention, the end of the CIGS layer or the end of the solar cell may be sealed. As a material for sealing, the same material as the glass substrate for CIGS solar cells of this invention, other glass, and resin are mentioned, for example.
Note that the thickness of each layer of the solar cell shown in the accompanying drawings is not limited to the drawings.

本発明のＣＩＧＳ太陽電池において、ＣＩＧＳ層の形成方法は特に限定されるものではない。Ｓｅ以外の構成元素を含有成分としたプリカーサ膜を形成後、Ｈ２Ｓｅガス雰囲気中で熱処理を行う、いわゆるセレン化法でもよいし、各構成元素を物理蒸着する蒸着法でもよいし、または、ＣＩＧＳ粉末を用いてインクを調整し、スクリーン印刷後に熱処理を施して焼結させる印刷法でもよい。 In the CIGS solar cell of the present invention, the CIGS layer forming method is not particularly limited. After forming a precursor film containing a constituent element other than Se as a component, a so-called selenization method in which heat treatment is performed in an H 2 Se gas atmosphere, a vapor deposition method in which each constituent element is physically vapor-deposited, or A printing method may be used in which ink is prepared using CIGS powder, heat treatment is performed after screen printing, and sintering is performed.

本発明のＣＩＧＳ太陽電池において、セレン化法を用いる場合、第１段階の温度は４００〜６００℃であることが好ましく、保持時間は５〜２０分が好ましい。また、第２段階の温度は５７０〜６００℃であることが好ましく、保持時間は２０〜６０分が好ましい。   In the CIGS solar cell of the present invention, when the selenization method is used, the first stage temperature is preferably 400 to 600 ° C., and the holding time is preferably 5 to 20 minutes. The second stage temperature is preferably 570 to 600 ° C., and the holding time is preferably 20 to 60 minutes.

本発明のＣＩＧＳ太陽電池用ガラス基板を用いたＣＩＧＳ太陽電池は、発電効率が１５％以上であることが好ましく、より好ましくは１６％以上、さらに好ましくは１７％以上である。なお、ここでいう発電効率は、後述の実施例で用いた発電効率の評価方法によって得られる発電効率とする。   The CIGS solar cell using the glass substrate for CIGS solar cell of the present invention preferably has a power generation efficiency of 15% or more, more preferably 16% or more, and further preferably 17% or more. The power generation efficiency referred to here is the power generation efficiency obtained by the power generation efficiency evaluation method used in the examples described later.

以下、実施例および製造例により本発明をさらに詳しく説明するが、本発明はこれら実施例および製造例に限定されない。
本発明のＣＩＧＳ太陽電池用ガラス基板の実施例（例１〜１０）および比較例（例１１〜１４）を示す。なお表１〜２中のかっこは、計算値である。 EXAMPLES Hereinafter, although an Example and a manufacture example demonstrate this invention in more detail, this invention is not limited to these Examples and a manufacture example.
The Example (Examples 1-10) and comparative example (Examples 11-14) of the glass substrate for CIGS solar cells of this invention are shown. The parentheses in Tables 1 and 2 are calculated values.

表１〜２で表示した組成になるように各成分の原料を調合し、該ガラス基板用成分の原料１００質量部に対し、硫酸塩をＳＯ３換算で０．１〜０．３質量部、Ｆｅ２Ｏ３を０．１質量部原料に添加し、白金坩堝を用いて１６００〜１６５０℃の温度で３時間加熱し溶解した。溶解にあたっては、白金スターラーを挿入し１時間攪拌しガラスの均質化を行った。次いで溶融ガラスを流し出し、板状に成形後冷却し、ガラス板を得た。
なお、表１〜２中、ＳＯ３およびＦｅ２Ｏ３以外の成分（ガラス基板用成分）は質量％換算であるが、ＳＯ３およびＦｅ２Ｏ３はガラス基板用成分の原料１００質量部に対する量（質量部）である。
こうして得られたガラス板の平均熱膨張係数（単位：×１０−７／℃）、ガラス転移点温度Ｔｇ（単位：℃）、粘度が１０４ｄＰａ・ｓとなる温度（Ｔ４）（単位：℃）、粘度が１０２ｄＰａ・ｓとなる温度（Ｔ２）（単位：℃）、失透温度（ＴＬ）（単位：℃）、密度（単位：ｇ／ｃｍ３）、発電効率を測定し、表１〜２に示した。以下に各物性の測定方法を示す。
なお、実施例では、ガラス板について各物性を測定しているが、各物性は、ガラス板とガラス基板とで同じ値である。得られたガラス板を加工、研磨を施すことで、ガラス基板とすることができる。 The raw materials of each component are prepared so as to have the compositions shown in Tables 1 and 2, and 0.1 to 0.3 parts by mass of sulfate in terms of SO 3 with respect to 100 parts by mass of the raw material for the glass substrate component, Fe 2 O 3 was added to 0.1 parts by mass of the raw material and dissolved by heating at a temperature of 1600 to 1650 ° C. for 3 hours using a platinum crucible. In melting, a platinum stirrer was inserted and stirred for 1 hour to homogenize the glass. Next, the molten glass was poured out, formed into a plate shape, and then cooled to obtain a glass plate.
In Tables 1 and 2 , components other than SO 3 and Fe 2 O 3 (components for glass substrate) are in terms of mass%, but SO 3 and Fe 2 O 3 are based on 100 parts by mass of the raw material for glass substrate components. Amount (parts by mass).
The glass plate thus obtained has an average coefficient of thermal expansion (unit: × 10 −7 / ° C.), a glass transition temperature T g (unit: ° C.), and a temperature (T 4 ) at which the viscosity becomes 10 4 dPa · s (unit). : ° C.), the temperature at which the viscosity becomes 10 2 dPa · s (T 2 ) ( unit: ° C.), devitrification temperature (T L) (unit: ° C.), the density (unit: g / cm 3), the power generation efficiency Measured and shown in Tables 1-2. The measuring method of each physical property is shown below.
In addition, in an Example, although each physical property is measured about a glass plate, each physical property is the same value with a glass plate and a glass substrate. By processing and polishing the obtained glass plate, a glass substrate can be obtained.

（１）Ｔｇ：Ｔｇは示差熱膨張計（ＴＭＡ）を用いて測定した値であり、ＪＩＳ Ｒ３１０３−３（２００１年度）により求めた。
（２）５０〜３５０℃の平均熱膨張係数：示差熱膨張計（ＴＭＡ）を用いて測定し、ＪＩＳ Ｒ３１０２（１９９５年度）より求めた。
（３）粘度：回転粘度計を用いて測定し、粘度ηが１０２ｄＰａ・ｓとなるときの温度Ｔ２（溶解性の基準温度）と、粘度ηが１０４ｄＰａ・ｓとなるときの温度Ｔ４（成形性の基準温度）を測定した。 (1) T g : T g is a value measured using a differential thermal dilatometer (TMA), and was determined according to JIS R3103-3 (2001).
(2) Average thermal expansion coefficient of 50 to 350 ° C .: measured using a differential thermal dilatometer (TMA) and determined from JIS R3102 (1995).
(3) Viscosity: measured by using a rotational viscometer, and the temperature T 2 (solubility reference temperature) when the viscosity η is 10 2 dPa · s, when the viscosity η is 10 4 dPa · s Temperature T 4 (reference temperature for moldability) was measured.

（４）失透温度（ＴＬ）：ガラス板から切り出したガラス塊５ｇを白金皿に置き、所定温度で１７時間電気炉中で保持した。保持した後のガラス塊表面および内部に結晶が析出しない温度の最大値を失透温度とした。
（５）密度：泡を含まない約２０ｇのガラス塊をアルキメデス法によって測定した。 (4) Devitrification temperature (T L ): 5 g of glass lump cut out from the glass plate was placed on a platinum dish and kept in an electric furnace at a predetermined temperature for 17 hours. The maximum temperature at which crystals do not precipitate on the surface and inside of the glass lump after being held was defined as the devitrification temperature.
(5) Density: About 20 g of glass lump containing no foam was measured by Archimedes method.

（６）発電効率：得られたガラス板を太陽電池の基板に用い、以下に示すように評価用太陽電池を作製し、これを用いて発電効率について評価を行った。結果を表１〜２に示す。
評価用太陽電池の作製について、図２Ａ、図２Ｂ及び図３、およびその符号を用いて以下説明している。なお、評価用太陽電池の層構成は、図１の太陽電池のカバーガラス１９および反射防止膜１７を有さない以外は、図１に示す太陽電池の層構成とほぼ同様である。
得られたガラス板を大きさ３ｃｍ×３ｃｍ、厚さ１．１ｍｍに加工し、ガラス基板を得た。ガラス基板５ａの上に、スパッタ装置にて、プラス電極７ａとしてモリブデン膜を製膜した。製膜は室温にて実施し、厚み５００ｎｍのモリブデン膜を得た。
プラス電極７ａ（モリブデン膜）上にスパッタ装置にて、ＣｕＧａ合金ターゲットでＣｕＧａ合金層を製膜し、続いてＩｎターゲットを使用してＩｎ層を製膜することで、Ｉｎ−ＣｕＧａのプリカーサ膜を製膜した。製膜は室温にて実施した。蛍光Ｘ線によって測定したプリカーサ膜の組成が、Ｃｕ／（Ｇａ＋Ｉｎ）比が０．８、Ｇａ／（Ｇａ＋Ｉｎ）比が０．２５となるように各層の厚みを調整し、厚み６５０ｎｍのプリカーサ膜を得た。 (6) Power generation efficiency: Using the obtained glass plate as a solar cell substrate, a solar cell for evaluation was prepared as shown below, and the power generation efficiency was evaluated using this. The results are shown in Tables 1-2.
The production of the solar cell for evaluation will be described below with reference to FIGS. 2A, 2B and 3, and the reference numerals thereof. The layer configuration of the solar cell for evaluation is substantially the same as the layer configuration of the solar cell shown in FIG. 1 except that it does not have the cover glass 19 and the antireflection film 17 of the solar cell in FIG.
The obtained glass plate was processed into a size of 3 cm × 3 cm and a thickness of 1.1 mm to obtain a glass substrate. On the glass substrate 5a, the molybdenum film | membrane was formed into a film as the plus electrode 7a with the sputtering device. Film formation was performed at room temperature to obtain a molybdenum film having a thickness of 500 nm.
By depositing a CuGa alloy layer with a CuGa alloy target on the positive electrode 7a (molybdenum film) with a CuGa alloy target, and subsequently forming an In layer with the In target, an In—CuGa precursor film is formed. A film was formed. Film formation was performed at room temperature. The thickness of each layer was adjusted so that the composition of the precursor film measured by fluorescent X-rays was Cu / (Ga + In) ratio of 0.8 and Ga / (Ga + In) ratio of 0.25. Obtained.

プリカーサ膜をＲＴＡ(Ｒａｐｉｄ Ｔｈｅｒｍａｌ Ａｎｎｅａｌｉｎｇ)装置を用いてアルゴンおよびセレン化水素混合雰囲気（セレン化水素はアルゴンに対し５体積％）にて加熱処理した。まず、第１段階として５００℃で１０分保持を行い、ＣｕとＩｎとＧａとを、Ｓｅと反応させた。その後、第２段階として硫化水素雰囲気（硫化水素はアルゴンに対し５体積％）に置換した後、５７０〜６００℃で３０分保持してＣＩＧＳ結晶を硫化させることでＣＩＧＳ層９ａを得た。得られたＣＩＧＳ層９ａの厚みは２μｍであった。
ＣＩＧＳ層９ａ上にＣＢＤ(Ｃｈｅｍｉｃａｌ Ｂａｔｈ Ｄｅｐｏｓｉｔｉｏｎ)法にて、バッファ層１１ａとしてＣｄＳ層を製膜した。具体的には、まず、ビーカー内で、濃度０．０１Ｍの硫酸カドミウム、濃度１．０Ｍのチオウレア、濃度１５Ｍのアンモニア、および純水を混合させた。次に、ＣＩＧＳ層を上記混合液に浸し、ビーカーごと予め水温を７０℃にしておいた恒温バス槽に入れ、ＣｄＳ層を５０〜８０ｎｍ製膜した。 The precursor film was heat-treated using a RTA (Rapid Thermal Annealing) apparatus in a mixed atmosphere of argon and hydrogen selenide (hydrogen selenide is 5% by volume with respect to argon). First, as a first step, holding was performed at 500 ° C. for 10 minutes, and Cu, In, and Ga were reacted with Se. Thereafter, as a second stage, the atmosphere was replaced with a hydrogen sulfide atmosphere (hydrogen sulfide is 5% by volume with respect to argon), and then held at 570 to 600 ° C. for 30 minutes to sulfidize the CIGS crystal to obtain the CIGS layer 9a. The thickness of the obtained CIGS layer 9a was 2 μm.
A CdS layer was formed as the buffer layer 11a on the CIGS layer 9a by the CBD (Chemical Bath Deposition) method. Specifically, first, cadmium sulfate having a concentration of 0.01M, thiourea having a concentration of 1.0M, ammonia having a concentration of 15M, and pure water were mixed in a beaker. Next, the CIGS layer was immersed in the above mixed solution, and the beaker was placed in a constant temperature bath whose water temperature was set to 70 ° C. in advance to form a CdS layer having a thickness of 50 to 80 nm.

さらにＣｄＳ層上にスパッタ装置にて、透明導電膜１３ａを以下の方法で製膜した。まず、ＺｎＯターゲットを使用してＺｎＯ層を製膜し、次に、ＡＺＯターゲット（Ａｌ２Ｏ３を１．５ｗｔ％含有するＺｎＯターゲット）を使用してＡＺＯ層を製膜した。各層の製膜は室温にて実施し、厚み４８０ｎｍの２層構成の透明導電膜１３ａを得た。
透明導電膜１３ａのＡＺＯ層上にＥＢ蒸着法により、Ｕ字型のマイナス電極１５ａとして膜厚１μｍのアルミ膜を製膜した（Ｕ字の電極長（縦８ｍｍ、横４ｍｍ）、電極幅０．５ｍｍ）。 Further, a transparent conductive film 13a was formed on the CdS layer by a sputtering apparatus by the following method. First, a ZnO layer was formed using a ZnO target, and then an AZO layer was formed using an AZO target (ZnO target containing 1.5 wt% Al 2 O 3 ). Film formation of each layer was performed at room temperature to obtain a transparent conductive film 13a having a two-layer structure with a thickness of 480 nm.
On the AZO layer of the transparent conductive film 13a, an aluminum film having a film thickness of 1 μm was formed as a U-shaped negative electrode 15a by EB vapor deposition (U-shaped electrode length (8 mm length, 4 mm width), electrode width 0. 5 mm).

最後に、メカニカルスクライブによって透明導電膜１３ａ側からＣＩＧＳ層９ａまでを削り、図２Ａ及び図２Ｂに示すようなセル化を行った。図２Ａは１つの太陽電池セルを上面から見た図であり、図２Ｂは図２Ａ中のＡ−Ａ’の断面図である。一つのセルは幅０．６ｃｍ、長さ１ｃｍで、マイナス電極１５ａを除いた面積が０．５ｃｍ２であり、図３に示すように、合計８個のセルが１枚のガラス基板５ａ上に得られた。
ソーラーシミュレータ（山下電装株式会社製、ＹＳＳ−Ｔ８０Ａ）に、評価用ＣＩＧＳ太陽電池（上記８個のセルを作製した評価用ガラス基板５ａ）を設置し、あらかじめＩｎＧａ溶剤を塗布したプラス電極７ａにプラス端子を（不図示）、マイナス電極１５ａのＵ字の下端にマイナス端子１６ａをそれぞれ電圧発生器に接続した。ソーラーシミュレータ内の温度は２５℃一定に温度調節機にて制御した。疑似太陽光を照射し、６０秒後に、電圧を−１Ｖから＋１Ｖまで０．０１５Ｖ間隔で変化させ、８個のセルのそれぞれの電流値を測定した。 Finally, mechanical scribe was used to scrape the transparent conductive film 13a side to the CIGS layer 9a, and cells were formed as shown in FIGS. 2A and 2B. 2A is a view of one solar battery cell as viewed from above, and FIG. 2B is a cross-sectional view taken along line AA ′ in FIG. 2A. One cell has a width of 0.6 cm and a length of 1 cm, and the area excluding the negative electrode 15a is 0.5 cm 2. As shown in FIG. 3, a total of eight cells are placed on one glass substrate 5a. Obtained.
CIGS solar cell for evaluation (evaluation glass substrate 5a produced with the above eight cells) was installed in a solar simulator (YSS-T80A, manufactured by Yamashita Denso Co., Ltd.), and added to plus electrode 7a previously coated with InGa solvent. A terminal (not shown) was connected to the voltage generator at the lower end of the U-shape of the negative electrode 15a. The temperature in the solar simulator was controlled at a constant temperature of 25 ° C. with a temperature controller. Pseudo sunlight was irradiated, and after 60 seconds, the voltage was changed from -1 V to +1 V at an interval of 0.015 V, and the current values of each of the eight cells were measured.

この照射時の電流と電圧特性から発電効率を下記式（１）により算出した。８個のセルのうち最も効率の良いセルの値を、各ガラス基板の発電効率の値として表１〜２に示す。
試験に用いた光源の照度は０．１Ｗ／ｃｍ２であった。
発電効率［％］＝Ｖｏｃ［Ｖ］×Ｊｓｃ［Ａ／ｃｍ2］×ＦＦ［無次元］×１００／試験に用いる光源の照度［Ｗ／ｃｍ2］ 式（１） The power generation efficiency was calculated by the following formula (1) from the current and voltage characteristics at the time of irradiation. The value of the most efficient cell among the eight cells is shown in Tables 1 and 2 as the value of the power generation efficiency of each glass substrate.
The illuminance of the light source used for the test was 0.1 W / cm 2 .
Power generation efficiency [%] = Voc [V] × Jsc [A / cm 2 ] × FF [Dimensionless] × 100 / Illuminance [W / cm 2 ] of the light source used in the test Equation (1)

発電効率は、開放電圧（Ｖｏｃ）と短絡電流密度（Ｊｓｃ）と曲線因子（ＦＦ）の掛け算で求められる。
なお、開放電圧（Ｖｏｃ）は端子を開放した時の出力であり、短絡電流（Ｉｓｃ）は短絡した時の電流である。短絡電流密度（Ｊｓｃ）はＩｓｃをマイナス電極を除いたセルの面積で割ったものである。 The power generation efficiency is obtained by multiplying the open circuit voltage (Voc), the short circuit current density (Jsc), and the fill factor (FF).
The open circuit voltage (Voc) is an output when the terminal is opened, and the short circuit current (Isc) is a current when the terminal is short circuited. The short circuit current density (Jsc) is Isc divided by the cell area excluding the negative electrode.

また最大の出力を与える点が最大出力点と呼ばれ、その点の電圧が最大電圧値（Ｖｍａｘ）、電流が最大電流値（Ｉｍａｘ）と呼ばれる。最大電圧値（Ｖｍａｘ）と最大電流値（Ｉｍａｘ）の掛け算の値を、開放電圧（Ｖｏｃ）と短絡電流（Ｉｓｃ）の掛け算の値で割った値が曲線因子（ＦＦ）として求められる。上記の値を使用し、発電効率を求めた。   The point that gives the maximum output is called the maximum output point, the voltage at that point is called the maximum voltage value (Vmax), and the current is called the maximum current value (Imax). A value obtained by dividing the product of the maximum voltage value (Vmax) and the maximum current value (Imax) by the product of the open circuit voltage (Voc) and the short circuit current (Isc) is obtained as a fill factor (FF). Using the above values, the power generation efficiency was determined.

ガラス板中のＳＯ３残存量は１００〜５００ｐｐｍ、Ｆｅ２Ｏ３残存量は０．１質量％であった。
なお、ガラス組成物中のＳＯ３の残存量は、ガラス板から切り出したガラスの塊を粉末状にして蛍光Ｘ線で評価し、測定した。 The residual amount of SO 3 in the glass plate was 100 to 500 ppm, and the residual amount of Fe 2 O 3 was 0.1% by mass.
In addition, the residual amount of SO 3 in the glass composition was measured by measuring a glass lump cut out from a glass plate in a powder form and evaluating with fluorescent X-rays.

Figure 2016172690
Figure 2016172690

Figure 2016172690
Figure 2016172690

表１〜２より明らかなように、実施例（例１〜１０）のガラス基板は、ガラス転移点温度Ｔｇが６４０℃以上と高く、平均熱膨張係数が７０×１０-7〜９０×１０-7／℃であり、密度が２．７ｇ／ｃｍ３以下と太陽電池用ガラス基板の特性をバランスよく有している。また、実施例（例１〜１０）のガラス板は、Ｔ４−ＴＬが−３０℃以上である。例２、例５及び例６のガラス板は、発電効率は１７．２％、１５．９％及び１６．５％で高い。
なお、例２、例５及び例６以外のガラス板の発電効率も１５％以上であった。 Table 1-2 As is clear from Examples (Examples 1-10) glass substrate of the glass transition temperature T g is as high as 640 ° C. or higher, × average thermal expansion coefficient 70 10 -7 ~90 × 10 −7 / ° C., and the density is not more than 2.7 g / cm 3, and the characteristics of the glass substrate for solar cells are well balanced. The glass plate of Example (Examples 1-10) is, T 4 -T L is -30 ° C. or higher. The glass plates of Examples 2, 5 and 6 have high power generation efficiency of 17.2%, 15.9% and 16.5%.
The power generation efficiency of the glass plates other than Example 2, Example 5 and Example 6 was also 15% or more.

一方、比較例である例１１のガラス板は、ＳｉＯ２−Ａｌ２Ｏ３が５０％超であり、ガラス転移点が６４０℃未満と耐熱性が不十分である。また、ＳｒＯおよびＢａＯの含有量が多いため、比重が増大した。
また、例１２および例１３のガラス板は、ＳｉＯ２−Ａｌ２Ｏ３は５０％未満であり、耐熱性は十分であるが、Ｋ２Ｏ／Ｎａ２Ｏは１．３超とＫ２Ｏの割合が多いため、発電効率が不十分である。
さらに例１４のガラス板はＫ２Ｏ／Ｎａ２Ｏは１．３以下でＮａ２Ｏの割合が多くなっているが、ＳｉＯ２−Ａｌ２Ｏ３が４３％未満でＡｌ２Ｏ３量が多過ぎるため、ＮａおよびＫの拡散量が抑制され、発電効率が不十分になったと考えられる。 On the other hand, the glass plate of Example 11 which is a comparative example has SiO 2 —Al 2 O 3 of more than 50% and has a glass transition point of less than 640 ° C. and insufficient heat resistance. In addition, the specific gravity increased due to the high SrO and BaO contents.
Further, the glass plates of Examples 12 and 13 have SiO 2 —Al 2 O 3 of less than 50% and sufficient heat resistance, but K 2 O / Na 2 O exceeds 1.3 and K 2 O Because of the large percentage, the power generation efficiency is insufficient.
Further, in the glass plate of Example 14, K 2 O / Na 2 O is 1.3 or less and the ratio of Na 2 O is large, but SiO 2 —Al 2 O 3 is less than 43% and the amount of Al 2 O 3 is small. Since it is too much, it is thought that the amount of diffusion of Na and K was suppressed, and the power generation efficiency became insufficient.

本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板は、ＣＩＧＳの太陽電池用のガラス基板、カバーガラスとして好適であるが、他の太陽電池用基板やカバーガラスに使用することもできる。   Although the glass substrate for Cu-In-Ga-Se solar cells of this invention is suitable as a glass substrate and cover glass for CIGS solar cells, it can also be used for other solar cell substrates and cover glasses.

以上、本発明を詳細に説明したが、これらは例示に過ぎず、本発明は、さらに別の態様でも実施でき、その主旨を逸脱しない範囲で種々変更を加えうるものである。
本出願は、２０１２年１月２０日付けで出願された日本特許出願（特願２０１２−００９６８１）に基づいており、その全体が引用により援用される。 Although the present invention has been described in detail above, these are merely examples, and the present invention can be implemented in other modes, and various modifications can be made without departing from the spirit of the present invention.
This application is based on a Japanese patent application filed on January 20, 2012 (Japanese Patent Application No. 2012-009681), which is incorporated by reference in its entirety.

本発明のＣｕ−Ｉｎ−Ｇａ−Ｓｅ太陽電池用ガラス基板は、高い発電効率、高いガラス転移点温度、所定の平均熱膨張係数、低いガラス密度、及び板ガラス生産時の失透防止の特性をバランスよく有することができ、本発明のＣＩＧＳ太陽電池用ガラス基板を用いることで発電効率の高い太陽電池を提供できる。   The glass substrate for Cu-In-Ga-Se solar cells of the present invention balances high power generation efficiency, high glass transition temperature, predetermined average thermal expansion coefficient, low glass density, and devitrification prevention characteristics during production of sheet glass. A solar cell with high power generation efficiency can be provided by using the glass substrate for CIGS solar cell of the present invention.

１ 太陽電池
５、５ａ ガラス基板
７、７ａ プラス電極
９、９ａ ＣＩＧＳ層
１１、１１ａ バッファ層
１３、１３ａ 透明導電膜
１５、１５ａ マイナス電極
１７ 反射防止膜
１９ カバーガラス DESCRIPTION OF SYMBOLS 1 Solar cell 5, 5a Glass substrate 7, 7a Positive electrode 9, 9a CIGS layer 11, 11a Buffer layer 13, 13a Transparent conductive film 15, 15a Negative electrode 17 Antireflection film 19 Cover glass

Claims (3)

下記酸化物基準の質量百分率表示で、
ＳｉＯ２を６０％超過、
ＺｒＯ２を０．５〜５％、
Ｎａ２Ｏを４〜８％、
Ａｌ２Ｏ３、ＭｇＯ、ＣａＯを含み、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯを１３．１％以下、
Ｎａ２Ｏ+Ｋ２Ｏを１２．５％以下含有し、
ＳｉＯ２−Ａｌ２Ｏ３が４３％以上５０％未満であり、
Ｋ２Ｏ／Ｎａ２Ｏが１．３以下であり、
ガラス転移点温度が６４０℃以上、密度が２．７ｇ／ｃｍ３以下である、ガラス基板。 In mass percentage display based on the following oxides,
The SiO 2 60% excess,
ZrO 2 0.5-5%,
Na 2 O 4-8%,
Including Al 2 O 3 , MgO, CaO,
MgO + CaO + SrO + BaO is 13.1% or less,
Na 2 O + K 2 O is contained at 12.5% or less,
SiO 2 —Al 2 O 3 is 43% or more and less than 50%,
K 2 O / Na 2 O is 1.3 or less,
A glass substrate having a glass transition temperature of 640 ° C. or higher and a density of 2.7 g / cm 3 or lower. 下記酸化物基準の質量百分率表示で、
Ａｌ２Ｏ３を１０％以上、
ＭｇＯを５％以下、
ＣａＯを３％以上、
ＭｇＯ＋ＣａＯ＋ＳｒＯ＋ＢａＯを３％以上、
Ｋ２Ｏ／Ｎａ２Ｏが１．２以下であり、
ガラス転移点温度が６５０℃以上である、請求項１に記載のガラス基板。 In mass percentage display based on the following oxides,
10% or more of Al 2 O 3
5% or less of MgO
3% or more of CaO,
3% or more of MgO + CaO + SrO + BaO,
K 2 O / Na 2 O is 1.2 or less,
The glass substrate of Claim 1 whose glass transition temperature is 650 degreeC or more. 密度が２．６ｇ／ｃｍ３以下である、請求項１または２に記載のガラス基板。 The glass substrate according to claim 1, wherein the density is 2.6 g / cm 3 or less.
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TW201542485A (en) * 2014-05-15 2015-11-16 Asahi Glass Co Ltd Glass substrate for solar cell and solar cell using the same
JP5951152B1 (en) * 2014-09-19 2016-07-13 旭硝子株式会社 Glass substrate and CIGS solar cell
GB201505091D0 (en) 2015-03-26 2015-05-06 Pilkington Group Ltd Glass

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