JP2013120807A - Paste composition for solar cell electrode - Google Patents

Paste composition for solar cell electrode Download PDF

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JP2013120807A
JP2013120807A JP2011267345A JP2011267345A JP2013120807A JP 2013120807 A JP2013120807 A JP 2013120807A JP 2011267345 A JP2011267345 A JP 2011267345A JP 2011267345 A JP2011267345 A JP 2011267345A JP 2013120807 A JP2013120807 A JP 2013120807A
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Takamasa Aoyama
貴征 青山
Yasushi Yoshino
泰 吉野
Shige Sakamoto
樹 阪本
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Noritake Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a paste composition for a solar cell electrode, with which the control of an entry amount of an electrode material can be easily performed even when an electrode is formed by a fire-through method in a solar cell having a shallow emitter structure with a thin n layer, and a solar cell high in FF value, low in leakage current and high in efficiency can be obtained.SOLUTION: A light-receiving surface electrode is configured of a thick silver film that contains 1-10 pts.wt. of lead glass relative to 100 pts.wt. of silver, the lead glass having a composition that contains 6-62 (mol%) of PbO, 1-18 (mol%) of BO, 8-49 (mol%) of SiO, 0-30 (mol%) of AlO, 1-30 (mol%) of LiO, 1-30 (mol%) of TiO, 0-30 (mol%) of ZnO, 0-1.0 (mol%) of ZrO, and 0-6 (mol%) of PO, respectively. Accordingly, an eroded amount is controlled in a range of about 80-90 (nm), so that, even though a line width is narrowed to about 100 (μm), good ohmic contact is obtained, and a photoelectric conversion efficiency of a solar cell is enhanced.

Description

本発明は、ファイヤースルー法で形成する太陽電池電極用に好適な導電性ペースト組成物に関する。   The present invention relates to a conductive paste composition suitable for a solar cell electrode formed by a fire-through method.

例えば、一般的なシリコン系太陽電池は、ｐ型多結晶半導体であるシリコン基板の上面に燐等のドナー元素をドーピングして形成したｎ層を介して反射防止膜および受光面電極が備えられると共に、下面にｐ+層を介して裏面電極(以下、これらを区別しないときは単に「電極」という。)が備えられた構造を有しており、受光により半導体のｐｎ接合に生じた電力を電極を通して取り出すようになっている。上記反射防止膜は、十分な可視光透過率を保ちつつ表面反射率を低減して受光効率を高めるためのもので、窒化珪素、二酸化チタン、二酸化珪素等の薄膜から成る。 For example, a general silicon-based solar cell includes an antireflection film and a light-receiving surface electrode through an n layer formed by doping a donor element such as phosphorus on the upper surface of a silicon substrate that is a p-type polycrystalline semiconductor. , And has a structure in which a back surface electrode (hereinafter simply referred to as “electrode” when not distinguished from each other) is provided via a p + layer on the lower surface, and power generated at the pn junction of the semiconductor by light reception is applied to the electrode. It comes to take out through. The antireflection film is for reducing the surface reflectance and increasing the light receiving efficiency while maintaining a sufficient visible light transmittance, and is made of a thin film such as silicon nitride, titanium dioxide, or silicon dioxide.

上記の反射防止膜は電気抵抗値が高いことから、半導体のｐｎ接合に生じた電力を効率よく取り出すことの妨げとなる。そこで、太陽電池の受光面電極は、例えば、ファイヤースルーと称される方法で形成される。この電極形成方法では、例えば、前記反射防止膜をｎ層上の全面に設けた後、例えばスクリーン印刷法を用いてその反射防止膜上に導電性ペーストすなわちペースト状の電極材料を適宜の形状で塗布し、焼成処理を施す。これにより、電極材料が加熱熔融させられると同時にこれに接触している反射防止膜が熔融させられ、受光面電極と半導体とが接触させられる。上記導電性ペーストは、例えば、銀粉末と、ガラスフリット(ガラス原料を溶融し急冷した後に必要に応じて粉砕したフレーク状または粉末状のガラスのかけら)と、有機質ベヒクルと、有機溶媒とを主成分とするもので、焼成過程において、この導電性ペースト中のガラス成分が反射防止膜を破るので、導電性ペースト中の導体成分とｎ層とによってオーミックコンタクトが形成される(例えば、特許文献１を参照。)。この導電性ペーストには、燐、バナジウム、ビスマス、タングステン等の金属或いは化合物等から成る各種微量成分を配合することで導通性を得ることが行われている。上記電極形成方法によれば、反射防止膜を部分的に除去してその除去部分に電極を形成する場合に比較して工程が簡単になり、除去部分と電極形成位置との位置ずれの問題も生じない利点がある。   Since the above-described antireflection film has a high electric resistance value, it prevents an electric power generated at the pn junction of the semiconductor from being efficiently extracted. Therefore, the light-receiving surface electrode of the solar cell is formed by a method called fire-through, for example. In this electrode formation method, for example, after the antireflection film is provided on the entire surface of the n layer, a conductive paste, that is, a paste-like electrode material is formed in an appropriate shape on the antireflection film by using, for example, a screen printing method. Apply and bake. As a result, the electrode material is heated and melted, and at the same time, the antireflection film in contact with the electrode material is melted, and the light receiving surface electrode and the semiconductor are brought into contact with each other. The conductive paste is mainly composed of, for example, silver powder, glass frit (a piece of flaky or powdered glass that is crushed as necessary after melting and quenching the glass raw material), an organic vehicle, and an organic solvent. Since the glass component in the conductive paste breaks the antireflection film in the baking process, an ohmic contact is formed by the conductive component in the conductive paste and the n layer (for example, Patent Document 1). See). In this conductive paste, conductivity is obtained by blending various trace components made of a metal or a compound such as phosphorus, vanadium, bismuth, and tungsten. According to the above electrode forming method, the process is simplified as compared with the case where the antireflection film is partially removed and an electrode is formed on the removed portion, and there is a problem of misalignment between the removed portion and the electrode forming position. There is an advantage that does not occur.

このような太陽電池の受光面電極形成において、ファイヤースルー性を向上させてオーミックコンタクトを改善し、延いては曲線因子(ＦＦ値)やエネルギー変換効率を高める等の目的で、従来から種々の提案が為されている。例えば、導電性ペーストに燐・バナジウム・ビスマス等の５族元素を添加することによって、ガラスおよび銀の反射防止膜に対する酸化還元作用を促進し、ファイヤースルー性を向上させたものがある(例えば、特許文献１を参照。)。また、導電性ペーストに塩化物、臭化物、或いはフッ化物を添加することで、ガラスおよび銀が反射防止膜を破る作用をこれら添加物が補助してオーミックコンタクトを改善するものがある(例えば、特許文献２を参照。)。上記フッ化物としては、フッ化リチウム、フッ化ニッケル、フッ化アルミニウムが示されている。また、上記各添加物に加えて５族元素を添加することも示されている。上記ガラスは例えば硼珪酸ガラスである。   In the formation of the light-receiving surface electrode of such a solar cell, various proposals have been made for the purpose of improving the fire-through property and improving the ohmic contact, and thus increasing the fill factor (FF value) and energy conversion efficiency. Has been made. For example, by adding a Group 5 element such as phosphorus, vanadium, bismuth or the like to the conductive paste, there is a material that promotes the redox action on the antireflection film of glass and silver and improves the fire-through property (for example, (See Patent Document 1). In addition, by adding chloride, bromide, or fluoride to the conductive paste, these additives help the glass and silver break the antireflection film, thereby improving ohmic contact (for example, patents). See reference 2.) Examples of the fluoride include lithium fluoride, nickel fluoride, and aluminum fluoride. It is also shown that a Group 5 element is added in addition to the above additives. The glass is, for example, borosilicate glass.

また、銀粉末と、亜鉛含有添加剤と、軟化点が300〜600(℃)の範囲内のガラスフリットとを有機溶媒中に分散した厚膜導電性組成物が提案されている(例えば、特許文献３を参照。)。この厚膜導電性組成物は太陽電池の受光面電極を形成するためのもので、亜鉛を添加することで導電性とはんだ接着性とが改善される。また、上記ガラスフリットとして、SiO2を21〜29(wt%)、Al2O3を0.1〜8(wt%)、PbOを50〜62(wt%)、B2O3を7〜10(wt%)、ZnOを0〜4(wt%)、Li2Oを0〜0.1(wt%)、TiO2を2〜7(wt%)含む鉛ガラスを用い得ることが示されている。 Further, a thick film conductive composition in which silver powder, a zinc-containing additive, and a glass frit having a softening point in a range of 300 to 600 (° C.) are dispersed in an organic solvent has been proposed (for example, a patent See reference 3.) This thick film conductive composition is for forming a light-receiving surface electrode of a solar cell, and conductivity and solder adhesion are improved by adding zinc. Further, as the glass frit, the SiO 2 21~29 (wt%), the Al 2 O 3 0.1~8 (wt% ), a PbO 50~62 (wt%), B 2 O 3 7-10 ( wt%), ZnO and 0~4 (wt%), Li 2 O and 0~0.1 (wt%), it has been shown that the TiO 2 may be used 2 to 7 (wt%) containing lead glass.

また、SiO2を1〜10(wt%)、B2O3を5〜15(wt%)、Al2O3を1〜15(wt%)、PbOを68〜89(wt%)、CuOを0〜10(wt%)、TiO2を0〜10(wt%)含み、軟化点が350〜500(℃)であるSiO2-B2O3-Al2O3-PbO系低融点ガラスを用いることにより、安定したオーミック接触を得ることのできる多結晶Si太陽電池の受光面電極用の導電性ペーストが示されている(例えば、特許文献４を参照。)。 Further, the SiO 2 1~10 (wt%), a B 2 O 3 5~15 (wt% ), the Al 2 O 3 1~15 (wt% ), a PbO 68~89 (wt%), CuO SiO 2 -B 2 O 3 -Al 2 O 3 -PbO-based low melting point glass containing 0 to 10 wt%, TiO 2 0 to 10 wt%, and having a softening point of 350 to 500 (° C.) A conductive paste for a light-receiving surface electrode of a polycrystalline Si solar cell that can obtain a stable ohmic contact by using is shown (for example, see Patent Document 4).

また、Si3N4やSiO2等から成る反射防止膜上に、Ag粉末、有機ビヒクル、ガラスフリット、およびTi,Bi,Co,Zn,Zr,Fe,Crの少なくとも一種とを含む電極材料を焼き付けることにより、安定したオーミックコンタクトおよび半田接着強度を得ようとするものがある(例えば、特許文献５を参照。)。Ti,Bi等は、Ag 100重量部に対して0.05〜5重量部が好ましいとされている。上記効果の得られる理由は示されていないが、Ti,Bi等が含まれていると、電極材料の焼成過程においてこれらがガラスに溶け込み、その後、電極材料が反射防止膜に作用するので、Ti,Bi等が含まれない場合に比較して反射防止膜との反応が安定化するものとされている。 In addition, an electrode material containing Ag powder, organic vehicle, glass frit, and at least one of Ti, Bi, Co, Zn, Zr, Fe, and Cr on an antireflection film made of Si 3 N 4 or SiO 2 or the like. There is one that attempts to obtain stable ohmic contact and solder bonding strength by baking (see, for example, Patent Document 5). Ti, Bi and the like are preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of Ag. The reason why the above effect is obtained is not shown, but if Ti, Bi, etc. are contained, they dissolve in the glass during the firing process of the electrode material, and then the electrode material acts on the antireflection film. Therefore, the reaction with the antireflection film is stabilized as compared with the case where Bi or the like is not contained.

特開昭６２−０４９６７６号公報Japanese Patent Laid-Open No. 62-049676 特開平１１−２１３７５４号公報JP 11-213754 A 特開２００６−３０２８９０号公報JP 2006-302890 A 特開２００９−０９９８７１号公報JP 2009-098771 A 特開２００１−３１３４００号公報JP 2001-313400 A

ところで、上述した太陽電池において、受光面側に位置するｎ層の不純物濃度を低くし或いはそのｎ層を薄く(すなわちドナー元素のドーピング深さを浅く)して、そのｎ層のシート抵抗を高くすること、すなわちシャローエミッタ化することが試みられている。これにより、表面再結合速度を低下させ、延いては電圧や取り出せる電流を向上させることができるので、太陽電池の高効率化が可能になる。このようにシャローエミッタ化すると、特に400(nm)付近の短波長側も発電に寄与するようになるため、太陽電池の効率向上の面では理想的な解と考えられている。シャローエミッタでは受光面側のｎ層厚みが70〜100(nm)と、従来のシリコン太陽電池セルの100〜200(nm)に比較して更に薄くされていることから、受光により発生した電気のうちｐｎ接合に達する前に熱に変わって有効に利用できなかった部分が減じられるため、短絡電流Iscが増大し、延いては発電効率が高められるのである。   By the way, in the solar cell described above, the impurity concentration of the n layer located on the light receiving surface side is lowered or the n layer is made thin (that is, the doping depth of the donor element is made shallow) to increase the sheet resistance of the n layer. Attempts have been made to create a shallow emitter. As a result, the surface recombination rate can be reduced, and thus the voltage and the current that can be extracted can be improved, so that the solar cell can be highly efficient. When a shallow emitter is formed in this way, the short wavelength side particularly near 400 (nm) also contributes to power generation, which is considered an ideal solution in terms of improving the efficiency of solar cells. In the shallow emitter, the thickness of the n layer on the light receiving surface side is 70 to 100 (nm), which is even thinner than the conventional silicon solar cell 100 to 200 (nm). Of these, the portion that could not be effectively used by changing to heat before reaching the pn junction is reduced, so that the short-circuit current Isc is increased, which in turn increases the power generation efficiency.

しかしながら、上記シャローエミッタのようにｎ層が薄いすなわちｐｎ接合部が浅い場合には、前述した受光面電極形成のための焼成処理において、ファイヤースルーで反射防止膜を十分に破り且つｐｎ接合部に電極材料が侵入しないような侵入深さ制御が非常に困難になる。そのため、リーク電流Idが増大し延いてはＦＦ値が低くなり易い問題がある。また、基板を焼成するにあたり、最高保持温度が高い場合や昇温開始から降温終了までの所要時間が長い場合など、熱量が強くかかる条件ではｐｎ接合部が一層損傷させられ易く、理論値よりも特性が低下し易い。そのため、良好な特性が得られる温度範囲すなわち焼成マージンが狭くなる。   However, when the n layer is thin like the shallow emitter, that is, the pn junction is shallow, the antireflection film is sufficiently broken by fire-through in the above-described firing process for forming the light receiving surface electrode, and the pn junction is formed. It is very difficult to control the penetration depth so that the electrode material does not penetrate. Therefore, there is a problem that the FF value tends to decrease as the leakage current Id increases and extends. Also, when firing the substrate, the pn junction is more easily damaged under conditions where the amount of heat is strong, such as when the maximum holding temperature is high or when the time required from the start of temperature increase to the end of temperature decrease is long, which is more than the theoretical value. Characteristics are likely to deteriorate. Therefore, the temperature range in which good characteristics can be obtained, that is, the firing margin is narrowed.

本発明は、以上の事情を背景として為されたもので、その目的は、ｎ層の薄いシャローエミッタ構造の太陽電池にファイヤースルー法で電極を形成する際にも電極材料の侵入量の制御が容易で、ＦＦ値が高く且つリーク電流が小さく高効率の太陽電池を得ることのできる太陽電池電極用ペースト組成物を提供することにある。   The present invention has been made in the background of the above circumstances, and its purpose is to control the amount of electrode material intrusion even when an electrode is formed by a fire-through method in a solar cell having a thin n-layer shallow emitter structure. An object of the present invention is to provide a solar cell electrode paste composition that is easy, has a high FF value, has a small leakage current, and can provide a highly efficient solar cell.

斯かる目的を達成するため、本発明の要旨とするところは、導電性粉末と、ガラスフリットと、ベヒクルとを含む太陽電池電極用ペースト組成物であって、前記ガラスフリットが酸化物換算で6〜62(mol%)のPbOと、1〜18(mol%)のB2O3と、8〜49(mol%)のSiO2と、1〜30(mol%)のLi2Oと、1〜30(mol%)のTiO2と、0〜6(mol%)のP2O5とを含み、且つPb/(Si＋Ti)(mol比)が0.2〜2.4の範囲内にあるガラスから成ることにある。 In order to achieve such an object, the gist of the present invention is a paste composition for a solar cell electrode containing a conductive powder, a glass frit, and a vehicle, wherein the glass frit is 6 in terms of oxide. and PbO of ~62 (mol%), and B 2 O 3 of 1~18 (mol%), and SiO 2 of 8~49 (mol%), and Li 2 O of 1~30 (mol%), 1 30 and TiO 2 of (mol%), 0~6 and a P 2 O 5 in (mol%), and Pb / (Si + Ti) ( mol ratio) be made of glass which is in the range of 0.2 to 2.4 It is in.

このようにすれば、太陽電池電極用ペースト組成物は、これを構成するガラスフリットが、6〜62(mol%)のPbO、1〜18(mol%)のB2O3、8〜49(mol%)のSiO2、1〜30(mol%)のLi2O、1〜30(mol%)のTiO2とを含み、且つPb/(Si＋Ti)(mol比)が0.2〜2.4の範囲内にあり、更に、必須ではないが好ましい成分としてP2O5を0〜6.0(mol%)の範囲で含むガラスから成ることから、ｐｎ接合部が浅い場合にも、電極材料の侵入を容易に制御できる。そのため、本発明のペースト組成物を受光面電極の形成に用いれば、リーク電流Idが小さく、曲線因子ＦＦ値が高く、電流値が大きく、且つ光電変換率が高い太陽電池モジュールを製造し得る。 In this way, a solar cell electrode paste composition, the glass frit constituting the this, PbO of 6~62 (mol%), 1~18 ( mol%) of B 2 O 3, 8~49 ( mol%) SiO 2 , 1 to 30 (mol%) Li 2 O, 1 to 30 (mol%) TiO 2 and Pb / (Si + Ti) (mol ratio) in the range of 0.2 to 2.4 Furthermore, although it is not essential, it is made of glass containing P 2 O 5 in a range of 0 to 6.0 (mol%) as a preferable component, so that even when the pn junction portion is shallow, the electrode material can be easily penetrated. Can be controlled. Therefore, when the paste composition of the present invention is used for forming the light-receiving surface electrode, a solar cell module having a small leak current Id, a high fill factor FF value, a large current value, and a high photoelectric conversion rate can be produced.

なお、前記ガラスフリット組成において、PbOは、ガラスの軟化点を低下させる成分で、低温焼成を可能とするための成分で、良好なファイヤースルー性を得るためにはPbOが6(mol%)以上且つ62(mol%)以下であることが必要である。PbO量が6(mol%)未満では軟化点が高くなり過ぎるのでガラス化が困難になると共に反射防止膜へ侵食し難くなり、延いては良好なオーミックコンタクトが得られなくなる。一方、62(mol%)を越えると軟化点が低くなり過ぎるので侵食性が強くなり過ぎてｐｎ接合部が破壊され、延いてはＦＦ値が小さくなる等の問題が生ずる。PbO量は、60(mol%)以下が一層好ましい。すなわち、6〜60(mol%)の範囲が一層好ましい。また、38(mol%)以上が更に好ましく、59(mol%)以下が更に好ましい。すなわち、38〜59(mol%)の範囲が特に好ましい。   In the glass frit composition, PbO is a component that lowers the softening point of the glass and is a component that enables low-temperature firing, and PbO is 6 (mol%) or more in order to obtain good fire-through properties. And it is necessary to be 62 (mol%) or less. If the amount of PbO is less than 6 (mol%), the softening point becomes too high, making it difficult to vitrify and erosion of the antireflection film, and as a result, good ohmic contact cannot be obtained. On the other hand, if it exceeds 62 (mol%), the softening point becomes too low and the erosion becomes so strong that the pn junction is broken, and the FF value becomes small. The amount of PbO is more preferably 60 (mol%) or less. That is, the range of 6 to 60 (mol%) is more preferable. Further, 38 (mol%) or more is more preferable, and 59 (mol%) or less is more preferable. That is, the range of 38 to 59 (mol%) is particularly preferable.

また、B2O3は、ガラス形成酸化物(すなわちガラスの骨格を作る成分)であり、ガラスの軟化点を低くするための成分で、良好なファイヤースルー性を得るためにはB2O3が1(mol%)以上且つ18(mol%)以下であることが必要である。B2O3量が1(mol%)未満では軟化点が高くなり過ぎるので反射防止膜へ侵食し難くなり、延いては良好なオーミックコンタクトが得られなくなると共に、耐湿性も低下する。特に、本願発明においてはガラス中にLiが含まれることから、B2O3が1(mol%)以上含まれていないと著しく熔け難くなる。一方、18(mol%)を越えると軟化点が低くなり過ぎるので侵食性が強くなり過ぎてｐｎ接合部が破壊される等の問題が生ずる。何れにしても開放電圧Vocが低下する傾向がある。B2O3量は、3(mol%)以上が一層好ましく、12(mol%)以下が一層好ましい。すなわち、3〜12(mol%)の範囲が一層好ましい。また、8(mol%)以下が更に好ましい。すなわち、3〜8(mol%)の範囲が特に好ましい。 B 2 O 3 is a glass-forming oxide (that is, a component that forms a glass skeleton), and is a component for lowering the softening point of glass. To obtain good fire-through properties, B 2 O 3 Is required to be 1 (mol%) or more and 18 (mol%) or less. If the amount of B 2 O 3 is less than 1 (mol%), the softening point becomes too high, so that it is difficult for the antireflection film to erode. As a result, good ohmic contact cannot be obtained, and the moisture resistance also decreases. In particular, in the present invention, since Li is contained in the glass, it is extremely difficult to melt unless 1 (mol%) or more of B 2 O 3 is contained. On the other hand, if it exceeds 18 (mol%), the softening point becomes too low and the erosion becomes so strong that the pn junction is broken. In any case, the open circuit voltage Voc tends to decrease. The amount of B 2 O 3 is more preferably 3 (mol%) or more, and further preferably 12 (mol%) or less. That is, the range of 3 to 12 (mol%) is more preferable. Further, it is more preferably 8 (mol%) or less. That is, the range of 3 to 8 (mol%) is particularly preferable.

また、SiO2は、ガラス形成酸化物であり、ガラスの耐化学性を高くするための成分で、良好なファイヤースルー性を得るためにはSiO2が8(mol%)以上且つ49(mol%)以下であることが必要である。SiO2量が8(mol%)未満では耐化学性が不足すると共にガラス形成が困難になり、一方、49(mol%)を越えると軟化点が高くなり過ぎてガラス化し難くなって反射防止膜へ侵食し難くなり、延いては良好なオーミックコンタクトが得られなくなる。SiO2量は、32(mol%)以下が一層好ましい。 In addition, SiO 2 is a glass-forming oxide, a component for increasing the chemical resistance of the glass, SiO 2 is 8 (mol%) or more and 49 (mol%) to obtain good fire-through properties ) It must be: If the amount of SiO 2 is less than 8 (mol%), the chemical resistance is insufficient and glass formation becomes difficult.On the other hand, if it exceeds 49 (mol%), the softening point becomes too high and vitrification becomes difficult, resulting in an antireflection film. It becomes difficult to erode, and thus good ohmic contact cannot be obtained. The amount of SiO 2 is more preferably 32 (mol%) or less.

また、Li2Oは、ガラスの軟化点を低下させる成分で、良好なファイヤースルー性を得るためには、Li2Oが1.0(mol%)以上且つ30(mol%)以下であることが必要である。Li2Oが1.0(mol%)未満では軟化点が高くなり過ぎ延いては反射防止膜への侵食性が不十分になる。一方、30(mol%)を越えるとアルカリが溶出すると共に侵食性が強くなり過ぎるので却って電気的特性が低下する。因みに、Liは、拡散を促進することから一般に半導体に対しては不純物であって、特性を低下させる傾向があることから半導体用途では避けることが望まれるものである。特に、通常はPb量が多い場合にLiを含むと侵食性が強くなり過ぎて制御が困難になる傾向がある。しかしながら、上記のような太陽電池用途においては、Liを含むガラスを用いても特性低下が認められず、却って適量が含まれていることでファイヤースルー性が改善され、特性向上が認められた。Liはドナー元素であり、接触抵抗Rcを低くすることもでき、また、ドナー補償効果により焼成マージンが一層広がる利点もある。しかも、Liを含む組成とすることにより、良好なファイヤースルー性を得ることのできるガラスの組成範囲が広くなることが認められた。尤も、太陽電池用途においても、過剰に含まれると侵食性が強くなり過ぎ、電気的特性が低下する傾向にある。Li2O量は、12(mol%)以下が一層好ましい。 Further, Li 2 O is a component to lower the softening point of the glass, in order to obtain good fire-through property, Li 2 O is 1.0 (mol%) and not more than 30 (mol%) must be less that It is. When Li 2 O is less than 1.0 (mol%), the softening point becomes too high and the erosion property to the antireflection film becomes insufficient. On the other hand, if it exceeds 30 (mol%), the alkali is eluted and the erosion becomes too strong, so that the electrical characteristics are deteriorated. Incidentally, Li is generally an impurity for semiconductors because it promotes diffusion, and Li tends to deteriorate the characteristics, so it is desirable to avoid it in semiconductor applications. In particular, when Li is contained when the amount of Pb is large, the erodibility tends to be too strong and control tends to be difficult. However, in solar cell applications such as those described above, no deterioration in properties was observed even when glass containing Li was used, but the proper amount was included on the contrary, thereby improving the fire-through property and enhancing the properties. Li is a donor element, which can lower the contact resistance Rc, and has an advantage that the firing margin is further widened by the donor compensation effect. In addition, it was recognized that the composition range of the glass capable of obtaining good fire-through properties was increased by adopting a composition containing Li. However, even in solar cell applications, if included excessively, the erodibility becomes too strong, and the electrical characteristics tend to deteriorate. The amount of Li 2 O is more preferably 12 (mol%) or less.

また、TiO2は、接触抵抗Rcを低減し、延いては直列抵抗Rsを低減することで、ＦＦ値を高める作用があり、1.0(mol%)以上且つ30(mol%)以下の範囲で含まれることが必要である。Ti量が1.0(mol%)未満では、Rc、Rsを十分に低くできず、ＦＦ値が低くなる。一方、Tiが30(mol%)よりも多くなると軟化点が上昇するので焼成温度が1250(℃)以下である通常の焼成炉ではフリットの製造自体が困難になる。 In addition, TiO 2 has the effect of increasing the FF value by reducing the contact resistance Rc and thus reducing the series resistance Rs, and is included in the range of 1.0 (mol%) to 30 (mol%). It is necessary to be If the amount of Ti is less than 1.0 (mol%), Rc and Rs cannot be sufficiently lowered, and the FF value becomes low. On the other hand, when Ti exceeds 30 (mol%), the softening point increases, and therefore it becomes difficult to produce frit in a normal firing furnace having a firing temperature of 1250 (° C.) or less.

また、PbO、SiO2、TiO2は、それぞれ上記の範囲内にあるだけでなく、更にPb/(Si＋Ti)(mol比)が、0.2以上且つ2.4以下であることが必要である。Pb/(Si＋Ti)mol比が0.2未満すなわち(Si＋Ti)がPbに対して過剰では、熔けにくくなるのでファイヤースルー性が低下し、受光面電極およびｎ層間のRcが高くなり、延いてはＦＦ値が低下する。なお、熔けやすくするためにLiやZnを多くすることも考えられるが、これらではＦＦ値は一層低下する。一方、Pb/(Si＋Ti)mol比が2.4を超えると、Pbの影響が大きくなることから侵食性が強くなり過ぎてｐｎ接合部が破壊されるため、Idが著しく大きくなるので、ＦＦ値が低下し、十分な出力特性が得られなくなる。要するに、前述したようにTiはガラス軟化点を上昇させることから、Siと同様にファイヤースルーの際の侵食量に影響を与えるので、Ti量を増やす場合には、Pb/(Si+Ti)mol比が上記範囲内となるようにPb量およびSi量を同時に調整して侵食量を制御することが必要である。Pb/(Si+Ti)は、2.0以下が一層好ましい。また、1.0以上が更に好ましく、1.9以下が更に好ましい。すなわち、1.0〜1.9が特に好ましい。 In addition, PbO, SiO 2 , and TiO 2 are not only in the above ranges, respectively, and Pb / (Si + Ti) (mol ratio) needs to be 0.2 or more and 2.4 or less. If the Pb / (Si + Ti) mol ratio is less than 0.2, that is, if (Si + Ti) is excessive with respect to Pb, it will be difficult to melt, so the fire-through property will decrease, the Rc between the light-receiving surface electrode and n layer will increase, and eventually the FF value Decreases. In order to make it easy to melt, it is conceivable to increase Li and Zn, but these lower the FF value further. On the other hand, when the Pb / (Si + Ti) mol ratio exceeds 2.4, the influence of Pb increases, so the erosion becomes so strong that the pn junction is destroyed, and Id is significantly increased, so the FF value decreases. As a result, sufficient output characteristics cannot be obtained. In short, as mentioned above, Ti raises the glass softening point, so it affects the amount of erosion during fire-through in the same way as Si, so when increasing the amount of Ti, Pb / (Si + Ti) mol It is necessary to control the amount of erosion by simultaneously adjusting the Pb amount and the Si amount so that the ratio is within the above range. Pb / (Si + Ti) is more preferably 2.0 or less. Further, 1.0 or more is more preferable, and 1.9 or less is more preferable. That is, 1.0 to 1.9 is particularly preferable.

因みに、導電性ペーストを構成するガラスフリット中にTiを含有させることで良好なオーミック接触を得て、延いてはＦＦ値の低下を抑制することが提案されている(前記特許文献４，５等を参照。)。Tiが含まれると、焼成時にシリサイドが形成されるので、前述したようにｎ型シリコン層および銀電極間のRcが低減させられるものと考えられる。高シート抵抗のシャローエミッタにおいては、このようなオーミック接触の改善が必須であるが、Tiには電極材料の侵入深さを深くする作用があるため、その侵入深さの制御が一層困難になる。これに対して、本願発明によれば、Pb/(Si+Ti)を上述したように適切な範囲に定めることで、Rcを低下させ且つ侵入深さ制御が容易になる利点がある。   Incidentally, it has been proposed to obtain a good ohmic contact by containing Ti in the glass frit constituting the conductive paste, thereby suppressing the decrease in the FF value (see Patent Documents 4 and 5, etc.). See). If Ti is contained, silicide is formed at the time of firing, so that it is considered that Rc between the n-type silicon layer and the silver electrode can be reduced as described above. Such ohmic contact improvements are essential for high sheet resistance shallow emitters, but Ti has the effect of increasing the penetration depth of the electrode material, making it more difficult to control the penetration depth. . On the other hand, according to the present invention, by setting Pb / (Si + Ti) to an appropriate range as described above, there is an advantage that Rc is lowered and penetration depth control is facilitated.

また、シャローエミッタを構成するに際しては、前述したようにｎ層が高シート抵抗化されるが、表面近傍のドナー元素濃度が低くされる場合には、Ag-Si間のバリア障壁が増加してオーミック接触の確保が困難になる。一方、ｎ層が薄くされる場合には侵入深さ制御が困難になって、ｎ層およびAg電極間のRcが増大する。何れにしてもＦＦ値の低下要因となっていたが、本発明によれば、上述したようにTi量およびPb/(Si+Ti)量を適切に制御することで、これらの問題が解消するのである。   In forming a shallow emitter, the n layer has a high sheet resistance as described above. However, when the donor element concentration near the surface is lowered, the barrier barrier between Ag and Si is increased, resulting in an ohmic contact. It is difficult to ensure contact. On the other hand, when the n layer is made thin, it becomes difficult to control the penetration depth, and Rc between the n layer and the Ag electrode increases. In any case, the FF value was reduced, but according to the present invention, these problems can be solved by appropriately controlling the Ti amount and the Pb / (Si + Ti) amount as described above. It is.

また、P2O5はｎ層に対するドナー元素であって、受光面電極のオーミックコンタクトの確保を容易にすることから、任意ではあるが含まれることが好ましい成分である。P2O5は6.0(mol%)以下であることが必要である。6.0(mol%)を超えると、ガラスが溶け難くなると共にデッドレイヤー(再結合速度の大きい層)が生ずる。 Further, P 2 O 5 is a donor element for the n layer, and is an optional component that is optionally included because it facilitates securing an ohmic contact of the light-receiving surface electrode. P 2 O 5 needs to be 6.0 (mol%) or less. If it exceeds 6.0 (mol%), the glass becomes difficult to melt and a dead layer (layer with a high recombination rate) is formed.

一般に、オーミックコンタクトを確保するためには、ドナー元素を高濃度で固溶させることが望ましい。一方、シャローエミッタを構成する高シート抵抗のセルでは、例えばSi3N4から成る反射防止膜の厚さ寸法を80(nm)程度として、電極による侵食量を80〜90(nm)の範囲内、すなわち10(nm)の精度で制御することが望ましい。しかしながら、このような制御は極めて困難であり、僅かに侵食過剰となった状態に制御せざるを得ない。そのため、侵食されたｎ層に対してドナー元素を補うことでその侵食過剰による出力低下を抑制する。斯かる条件下でオーミックコンタクトを確保するためには、ドナー元素の濃度を1019(個/cm3)以上、好ましくは1020(個/cm3)以上にすることが望ましいが、Li等のガラス成分以外でこのような高濃度を得ることのできる元素は、As、P、Sbに限られる。これらのうちAsは毒性が強いことから開放系で操作されるガラス製造では好まれないが、SbはPに代えて用い得る元素である。 In general, in order to ensure ohmic contact, it is desirable to dissolve the donor element in a high concentration. On the other hand, in the high sheet resistance cell constituting the shallow emitter, the thickness of the antireflection film made of, for example, Si 3 N 4 is set to about 80 (nm), and the amount of erosion by the electrode is in the range of 80 to 90 (nm). That is, it is desirable to control with an accuracy of 10 (nm). However, such control is extremely difficult and must be controlled to be slightly over-eroded. Therefore, the decrease in output due to excessive erosion is suppressed by supplementing the eroded n layer with a donor element. In order to ensure ohmic contact under such conditions, it is desirable that the concentration of the donor element be 10 19 (pieces / cm 3 ) or more, preferably 10 20 (pieces / cm 3 ) or more. Elements other than glass components that can obtain such a high concentration are limited to As, P, and Sb. Of these, As is highly toxic and is not preferred for glass production operated in an open system, but Sb is an element that can be used in place of P.

なお、上記各成分は、ガラス中に如何なる形態で含まれているか必ずしも特定が困難であるが、これらの割合は何れも酸化物換算した値とした。   In addition, although it is difficult to specify in which form each of the above components is contained in the glass, these ratios are all values converted to oxides.

また、本発明の導電性ペーストを構成する前記ガラスは、その特性を損なわない範囲で他の種々のガラス構成成分や添加物を含み得る。例えば、Al、Zn、Zr、Na、Ca、Mg、K、Ba、Sr等が含まれていても差し支えない。これらは例えば合計30(mol%)以下の範囲で含まれ得る。これらのうち、Al、Znは、適量含まれることで並列抵抗Rshを向上させ、延いてはVocおよびIscを向上させる作用がある。なお、これらAlおよびZnは何れもアクセプタであるので、シャローエミッタにおいて必須とされるドナー補償を妨げる。これに対して、LiおよびPは前述したようにドナー補償効果があるので、AlやZnを含む場合には、LiやPを相当量含むことが望ましい。   In addition, the glass constituting the conductive paste of the present invention may contain other various glass components and additives as long as the properties are not impaired. For example, Al, Zn, Zr, Na, Ca, Mg, K, Ba, Sr, etc. may be contained. These may be included in a total range of 30 (mol%) or less, for example. Among these, Al and Zn are contained in appropriate amounts, thereby improving the parallel resistance Rsh, and thus improving Voc and Isc. Since both Al and Zn are acceptors, they obstruct donor compensation that is essential in a shallow emitter. On the other hand, since Li and P have a donor compensation effect as described above, when Al or Zn is contained, it is desirable to contain a considerable amount of Li or P.

また、本発明の導電性ペースト組成物は、上述したように容易に良好なオーミック接触が得られる。そのため、例えばシート抵抗値が80〜120(Ω/□)程度の高シート抵抗基板にも好適に適用される。しかしながら、これよりもシート抵抗値の低い基板にも適用可能であり、シャローエミッタではない従来構造の太陽電池用にも同様に適用可能である。また、ペースト中のガラス成分を従来に比較して少なくすることができることから、銀グリッド電極の抵抗値を低下させ得るので、細線化が容易な利点もある。   In addition, as described above, the conductive paste composition of the present invention can easily obtain good ohmic contact. Therefore, for example, the present invention is suitably applied to a high sheet resistance substrate having a sheet resistance value of about 80 to 120 (Ω / □). However, the present invention can be applied to a substrate having a sheet resistance value lower than this, and similarly applicable to a solar cell having a conventional structure that is not a shallow emitter. In addition, since the glass component in the paste can be reduced as compared with the conventional one, the resistance value of the silver grid electrode can be lowered, so that there is an advantage that thinning is easy.

ここで、好適には、前記ガラスは酸化物換算で6〜60(mol%)のPbOと、3〜12(mol%)のB2O3と、8〜32(mol%)のSiO2と、1〜30(mol%)のLi2Oと、1〜30(mol%)のTiO2と、0〜4(mol%)のP2O5とを含み、且つPb/(Si＋Ti)(mol比)が0.2〜2.0の範囲内にあることが望ましい。 Here, preferably, the glass and PbO having 6 to 60 in terms of oxides (mol%), and B 2 O 3 of 3 to 12 (mol%), and SiO 2 of 8 to 32 (mol%) 1-30 includes a Li 2 O of (mol%), and TiO 2 of 1 to 30 (mol%), and P 2 O 5 of 0 to 4 (mol%), and Pb / (Si + Ti) ( mol The ratio is preferably in the range of 0.2 to 2.0.

また、好適には、前記ガラスは酸化物換算で38〜59(mol%)のPbOと、3〜8(mol%)のB2O3と、8〜32(mol%)のSiO2と、1〜12(mol%)のLi2Oと、3〜30(mol%)のTiO2と、0〜2(mol%)のP2O5とを含み、且つPb/(Si＋Ti)(mol比)が1.0〜1.9の範囲内にあることが望ましい。 Also, preferably, the glass and PbO of 38 to 59 in terms of oxides (mol%), and B 2 O 3 of 3 to 8 (mol%), and SiO 2 of 8 to 32 (mol%), 1-12 and Li 2 O of (mol%), and TiO 2 of 3~30 (mol%), 0~2 and a P 2 O 5 in (mol%), and Pb / (Si + Ti) ( mol ratio ) Is preferably in the range of 1.0 to 1.9.

また、前記ガラスフリットは平均粒径(D50)が0.3〜3.0(μm)の範囲内である。ガラスフリットの平均粒径が小さすぎると電極の焼成時に融解が早すぎるため電気的特性が低下するが、0.3(μm)以上であれば適度な融解性が得られるので電気的特性が一層高められる。しかも、凝集が生じ難いのでペースト調製時に一層良好な分散性が得られる。また、ガラスフリットの平均粒径が導電性粉末の平均粒径よりも著しく大きい場合にも粉末全体の分散性が低下するが、3.0(μm)以下であれば一層良好な分散性が得られる。しかも、ガラスの一層の溶融性が得られる。したがって、一層良好なオーミックコンタクトを得るためには上記平均粒径が好ましい。   The glass frit has an average particle size (D50) in the range of 0.3 to 3.0 (μm). If the average particle size of the glass frit is too small, melting will be too early when the electrode is fired, resulting in a decrease in electrical characteristics, but if it is 0.3 (μm) or more, moderate melting properties can be obtained, so that the electrical characteristics are further enhanced. . In addition, since agglomeration is unlikely to occur, better dispersibility can be obtained during paste preparation. Also, the dispersibility of the entire powder is lowered when the average particle size of the glass frit is significantly larger than the average particle size of the conductive powder, but better dispersibility can be obtained when it is 3.0 (μm) or less. Moreover, a further melting property of the glass can be obtained. Therefore, in order to obtain a better ohmic contact, the average particle diameter is preferable.

なお、上記ガラスフリットの平均粒径は空気透過法による値である。空気透過法は、粉体層に対する流体(例えば空気)の透過性から粉体の比表面積を測定する方法をいう。この測定方法の基礎となるのは、粉体層を構成する全粒子の濡れ表面積とそこを通過する流体の流速および圧力降下の関係を示すコゼニー・カーマン(Kozeny-Carmann)の式であり、装置によって定められた条件で充填された粉体層に対する流速と圧力降下を測定して試料の比表面積を求める。この方法は充填された粉体粒子の間隙を細孔と見立てて、空気の流れに抵抗となる粒子群の濡れ表面積を求めるもので、通常はガス吸着法で求めた比表面積よりも小さな値を示す。求められた上記比表面積および粒子密度から粉体粒子を仮定した平均粒径を算出できる。   The average particle size of the glass frit is a value obtained by the air permeation method. The air permeation method is a method for measuring the specific surface area of a powder from the permeability of a fluid (for example, air) to a powder layer. The basis of this measurement method is the Kozeny-Carmann equation, which shows the relationship between the wetted surface area of all particles making up the powder layer and the flow velocity and pressure drop of the fluid passing therethrough. The specific surface area of the sample is obtained by measuring the flow velocity and pressure drop with respect to the powder layer filled under the conditions determined by the above. In this method, the gap between the filled powder particles is regarded as pores, and the wetted surface area of the particles that resists the flow of air is determined. Usually, the value is smaller than the specific surface area determined by the gas adsorption method. Show. An average particle diameter assuming powder particles can be calculated from the obtained specific surface area and particle density.

また、好適には、前記導電性粉末は平均粒径(D50)が0.3〜3.0(μm)の範囲内の銀粉末である。導電性粉末としては銅粉末やニッケル粉末等も用い得るが、銀粉末が高い導電性を得るために最も好ましい。また、銀粉末の平均粒径が3.0(μm)以下であれば一層良好な分散性が得られるので一層高い導電性が得られる。また、0.3(μm)以上であれば凝集が抑制されて一層良好な分散性が得られる。なお、0.3(μm)未満の銀粉末は著しく高価であるため、製造コストの面からも0.3(μm)以上が好ましい。また、導電性粉末、ガラスフリット共に平均粒径が3.0(μm)以下であれば、細線パターンで電極を印刷形成する場合にも目詰まりが生じ難い利点がある。   Preferably, the conductive powder is a silver powder having an average particle diameter (D50) in the range of 0.3 to 3.0 (μm). Although copper powder, nickel powder, etc. can be used as the conductive powder, silver powder is most preferable in order to obtain high conductivity. Further, if the average particle size of the silver powder is 3.0 (μm) or less, better dispersibility can be obtained, and thus higher conductivity can be obtained. Moreover, if it is 0.3 (μm) or more, aggregation is suppressed and better dispersibility can be obtained. Since silver powder of less than 0.3 (μm) is extremely expensive, 0.3 (μm) or more is preferable from the viewpoint of manufacturing cost. Further, if the average particle diameter of both the conductive powder and the glass frit is 3.0 (μm) or less, there is an advantage that clogging hardly occurs even when the electrode is printed by a fine line pattern.

なお、前記銀粉末は特に限定されず、球状や鱗片状等、どのような形状の粉末が用いられる場合にも導電性を保ったまま細線化が可能であるという本発明の基本的効果を享受し得る。但し、球状粉を用いた場合が印刷性に優れると共に、塗布膜における銀粉末の充填率が高くなるため、導電性の高い銀が用いられることと相俟って、鱗片状等の他の形状の銀粉末が用いられる場合に比較して、その塗布膜から生成される電極の導電率が高くなる。そのため、必要な導電性を確保したまま線幅を一層細くすることが可能となることから、特に好ましい。   The silver powder is not particularly limited, and enjoys the basic effect of the present invention that thinning can be achieved while maintaining conductivity even when a powder of any shape such as a spherical shape or a scale shape is used. Can do. However, when the spherical powder is used, the printability is excellent and the filling rate of the silver powder in the coating film is increased, so that, together with the use of highly conductive silver, other shapes such as scales are used. Compared with the case where the silver powder of this is used, the electrical conductivity of the electrode produced | generated from the coating film becomes high. Therefore, it is particularly preferable because the line width can be further reduced while ensuring the necessary conductivity.

また、好適には、前記太陽電池電極用ペースト組成物は、25(℃)−20(rpm)における粘度が150〜250(Pa・s)の範囲内、粘度比(すなわち、10(rpm)における粘度/100(rpm)における粘度)が3〜8である。このような粘度特性を有するペーストを用いることにより、スキージングの際に好適に低粘度化してスクリーンメッシュを透過し、その透過後には高粘度に戻って印刷幅の広がりが抑制されるので、スクリーンを容易に透過して目詰まりを生じないなど印刷性を保ったまま細線パターンが容易に得られる。ペースト組成物の粘度は、180〜230(Pa・s)の範囲が一層好ましく、粘度比は3.2〜6.5の範囲が一層好ましい。また、設計線幅が100(μm)以下の細線化には粘度比4〜6が望ましい。   Also preferably, the solar cell electrode paste composition has a viscosity at 25 (° C.)-20 (rpm) in the range of 150 to 250 (Pa · s), a viscosity ratio (ie, 10 (rpm)). Viscosity / viscosity at 100 (rpm)) is 3-8. By using a paste having such a viscosity characteristic, the viscosity is suitably reduced during squeezing and transmitted through the screen mesh. After the transmission, the viscosity returns to a high viscosity and the expansion of the printing width is suppressed. Thus, a fine line pattern can be easily obtained while maintaining the printability such that clogging does not easily occur and clogging does not occur. The viscosity of the paste composition is more preferably in the range of 180 to 230 (Pa · s), and the viscosity ratio is more preferably in the range of 3.2 to 6.5. In addition, a viscosity ratio of 4 to 6 is desirable for thinning a design line width of 100 (μm) or less.

なお、線幅を細くしても断面積が保たれるように膜厚を厚くすることは、例えば、印刷製版の乳剤厚みを厚くすること、テンションを高くすること、線径を細くして開口径を広げること等でも可能である。しかしながら、乳剤厚みを厚くすると版離れが悪くなるので印刷パターン形状の安定性が得られなくなる。また、テンションを高くし或いは線径を細くすると、スクリーンメッシュが伸び易くなるので寸法・形状精度を保つことが困難になると共に印刷製版の耐久性が低下する問題がある。しかも、太幅で設けられることから膜厚を厚くすることが無用なバスバーも厚くなるため、材料の無駄が多くなる問題もある。   Note that increasing the film thickness so that the cross-sectional area can be maintained even if the line width is reduced includes, for example, increasing the emulsion thickness of the printing plate, increasing the tension, and reducing the line diameter. It is also possible to widen the aperture. However, when the emulsion thickness is increased, the separation of the plate is deteriorated, so that the stability of the printed pattern shape cannot be obtained. In addition, when the tension is increased or the wire diameter is reduced, the screen mesh is easily stretched, so that it is difficult to maintain the dimensional and shape accuracy and the durability of the printing plate making is lowered. In addition, since it is provided with a large width, a bus bar that is unnecessary to increase the film thickness is also increased, resulting in a problem of waste of material.

また、好適には、前記太陽電池電極用ペースト組成物は、前記導電性粉末を74〜90重量部、前記ベヒクルを3〜20重量部の範囲内の割合で含むものである。このようにすれば、印刷性が良好で線幅の細く導電性の高い電極を容易に形成できるペースト組成物が得られる。   Preferably, the solar cell electrode paste composition includes the conductive powder in a proportion of 74 to 90 parts by weight and the vehicle in a proportion of 3 to 20 parts by weight. In this way, a paste composition can be obtained that can easily form an electrode having good printability, thin line width, and high conductivity.

また、好適には、前記導電性ペースト組成物は、前記ガラスフリットを前記導電性粉末100重量部に対して1〜10重量部の範囲で含むものである。1重量部以上含まれていれば十分な侵食性(ファイヤスルー性)が得られるので、一層良好なオーミックコンタクトが得られる。また、10重量部以下に留められていれば絶縁層が形成され難いので十分な導電性が得られる。導電性粉末100重量部に対するガラス量は、1〜8重量部が一層好ましく、1〜7重量部が更に好ましい。   Preferably, the conductive paste composition contains the glass frit in a range of 1 to 10 parts by weight with respect to 100 parts by weight of the conductive powder. If it is contained in an amount of 1 part by weight or more, sufficient erosion property (fire-through property) can be obtained, so that a better ohmic contact can be obtained. Further, if it is kept at 10 parts by weight or less, it is difficult to form an insulating layer, and sufficient conductivity can be obtained. The amount of glass based on 100 parts by weight of the conductive powder is more preferably 1 to 8 parts by weight, and still more preferably 1 to 7 parts by weight.

また、本願発明の導電性ペースト組成物は、前述したようにファイヤースルーによる電極形成時の銀の拡散を好適に制御し得るものであるから、受光面電極に好適に用い得る。また、受光面に設けられる反射防止膜の構成材料は、酸化チタン、二酸化珪素、窒化珪素等種々のものが挙げられる。本発明のペーストは何れの場合にも適用可能であるが、特に窒化珪素薄膜で反射防止膜が構成される場合に好適である。   In addition, since the conductive paste composition of the present invention can suitably control the diffusion of silver when forming an electrode by fire-through as described above, it can be suitably used for a light-receiving surface electrode. Examples of the constituent material of the antireflection film provided on the light receiving surface include various materials such as titanium oxide, silicon dioxide, and silicon nitride. The paste of the present invention can be applied to any case, but is particularly suitable when the antireflection film is formed of a silicon nitride thin film.

また、前記ガラスフリットは、前記組成範囲でガラス化可能な種々の原料から合成することができ、例えば、酸化物、水酸化物、炭酸塩、硝酸塩等が挙げられるが、例えば、Si源としては二酸化珪素SiO2を、B源としては硼酸B2O3を、Pb源としては鉛丹Pb3O4を用い得る。また、Ti源としては酸化チタン TiO2を、Li源としては炭酸リチウム Li2CO3を、P源としてはリン酸二水素アンモニウム NH4H2PO4を、Al源としては酸化アルミニウム Al2O3を、それぞれ用い得る。 Further, the glass frit can be synthesized from various raw materials that can be vitrified within the composition range, and examples thereof include oxides, hydroxides, carbonates, nitrates, etc. Silicon dioxide SiO 2 can be used, boric acid B 2 O 3 can be used as the B source, and red lead Pb 3 O 4 can be used as the Pb source. Titanium oxide TiO 2 as the Ti source, lithium carbonate Li 2 CO 3 as the Li source, ammonium dihydrogen phosphate NH 4 H 2 PO 4 as the P source, and aluminum oxide Al 2 O as the Al source 3 may be used respectively.

本発明の一実施例の電極用ペースト組成物が受光面電極の形成に適用された太陽電池を備えた太陽電池モジュールの断面構造を示す模式図である。It is a schematic diagram which shows the cross-section of the solar cell module provided with the solar cell with which the paste composition for electrodes of one Example of this invention was applied for formation of a light-receiving surface electrode. 図１の太陽電池の受光面電極パターンの一例を示す図である。It is a figure which shows an example of the light-receiving surface electrode pattern of the solar cell of FIG. (ａ)、(ｂ)は接触抵抗測定用の電極パターンを説明するための平面図および側面図である。(a), (b) is the top view and side view for demonstrating the electrode pattern for contact resistance measurement. 図３の測定方法により得られたライン間隔と抵抗値との関係を示す図である。It is a figure which shows the relationship between the line space | interval and resistance value which were obtained by the measuring method of FIG. 接触抵抗の測定原理を説明する図である。It is a figure explaining the measurement principle of contact resistance.

以下、本発明の一実施例を図面を参照して詳細に説明する。なお、以下の実施例において図は適宜簡略化或いは変形されており、各部の寸法比および形状等は必ずしも正確に描かれていない。   Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

図１は、本発明の一実施例の導電性組成物が適用されたシリコン系太陽電池１０を備えた太陽電池モジュール１２の断面構造を模式的に示す図である。図１において、太陽電池モジュール１２は、上記太陽電池１０と、これを封止する封止材１４と、受光面側において封止材１４上に設けられた表面ガラス１６と、裏面側から太陽電池１０および封止材１４を保護するために設けられた保護フィルム(すなわちバックシート)１８とを備えている。上記封止材１４は、例えば、ＥＶＡから成るもので、十分な耐候性を有するように、架橋剤、紫外線吸収剤、接着保護剤等が適宜配合されている。また、上記保護フィルム１８は、例えば弗素樹脂やポリエチレンテレフタレート(ＰＥＴ)樹脂、或いはＰＥＴやＥＶＡ等から成る樹脂フィルムを複数枚貼り合わせたもの等から成るもので、高い耐候性や水蒸気バリア性等を備えている。   FIG. 1 is a diagram schematically showing a cross-sectional structure of a solar cell module 12 including a silicon-based solar cell 10 to which a conductive composition according to an embodiment of the present invention is applied. In FIG. 1, the solar cell module 12 includes the solar cell 10, a sealing material 14 for sealing the solar cell 10, a surface glass 16 provided on the sealing material 14 on the light receiving surface side, and a solar cell from the back surface side. 10 and a protective film (that is, a back sheet) 18 provided to protect the sealing material 14. The sealing material 14 is made of, for example, EVA, and is appropriately blended with a crosslinking agent, an ultraviolet absorber, an adhesion protective agent and the like so as to have sufficient weather resistance. The protective film 18 is made of, for example, fluorine resin, polyethylene terephthalate (PET) resin, or a laminate of a plurality of resin films made of PET, EVA, etc., and has high weather resistance, water vapor barrier properties, etc. I have.

また、上記の太陽電池１０は、例えばｐ型多結晶半導体であるシリコン基板２０と、その上下面にそれぞれ形成されたｎ層２２およびｐ+層２４と、そのｎ層２２上に形成された反射防止膜２６および受光面電極２８と、そのｐ+層２４上に形成された裏面電極３０とを備えている。上記シリコン基板２０の厚さ寸法は例えば100〜200(μm)程度である。 The solar cell 10 includes, for example, a silicon substrate 20 which is a p-type polycrystalline semiconductor, an n layer 22 and a p + layer 24 respectively formed on the upper and lower surfaces thereof, and a reflection formed on the n layer 22. A prevention film 26 and a light receiving surface electrode 28, and a back electrode 30 formed on the p + layer 24 are provided. The thickness dimension of the silicon substrate 20 is, for example, about 100 to 200 (μm).

上記のｎ層２２およびｐ+層２４は、シリコン基板２０の上下面に不純物濃度の高い層を形成することで設けられたもので、その高濃度層の厚さ寸法はｎ層２２が例えば70〜100(nm)程度、ｐ+層２４が例えば500(nm)程度である。ｎ層２２は、一般的なシリコン系太陽電池では100〜200(nm)程度であるが、本実施例ではそれよりも薄くなっており、シャローエミッタと称される構造を成している。なお、ｎ層２２に含まれる不純物は、ｎ型のドーパント、例えば燐(P)で、ｐ+層２４に含まれる不純物は、ｐ型のドーパント、例えばアルミニウム(Al)や硼素(B)である。 The n layer 22 and the p + layer 24 are provided by forming layers having a high impurity concentration on the upper and lower surfaces of the silicon substrate 20, and the thickness dimension of the high concentration layer is, for example, 70 n. ˜100 (nm), and the p + layer 24 is about 500 (nm), for example. The n layer 22 is about 100 to 200 (nm) in a general silicon-based solar cell, but is thinner than that in this embodiment, and has a structure called a shallow emitter. The impurity contained in the n layer 22 is an n-type dopant such as phosphorus (P), and the impurity contained in the p + layer 24 is a p-type dopant such as aluminum (Al) or boron (B). .

また、前記の反射防止膜２６は、例えば、窒化珪素 Si3N4等から成る薄膜で、例えば可視光波長の１／４程度の光学的厚さ、例えば80(nm)程度で設けられることによって10(％)以下、例えば2(％)程度の極めて低い反射率に構成されている。 The antireflection film 26 is a thin film made of, for example, silicon nitride Si 3 N 4 , and is provided with an optical thickness of, for example, about 1/4 of the visible light wavelength, for example, about 80 (nm). It is configured to have an extremely low reflectance of 10 (%) or less, for example, 2 (%).

また、前記の受光面電極２８は、例えば一様な厚さ寸法の厚膜導体から成るもので、図２に示されるように、受光面３２の略全面に、多数本の細線部を有する櫛状を成す平面形状で設けられている。   The light receiving surface electrode 28 is made of, for example, a thick film conductor having a uniform thickness. As shown in FIG. 2, the light receiving surface electrode 28 is a comb having a large number of thin line portions substantially on the entire surface of the light receiving surface 32. Are provided in a planar shape.

上記の厚膜導体は、Agを100重量部に対してガラスを1〜10重量部の範囲で、例えば6.0重量部含む厚膜銀から成るもので、そのガラスは酸化物換算した値で、PbOを6〜62(mol%)の範囲内、例えば39.0(mol%)、B2O3を1〜18(mol%)の範囲内、例えば8.0(mol%)、SiO2を8〜49(mol%)の範囲内、例えば31.0(mol%)、Al2O3を0〜30(mol%)の範囲内、例えば3.0(mol%)、Li2Oを1〜30(mol%)の範囲内、例えば12.0(mol%)、TiO2を1〜30(mol%)の範囲内、例えば3.0(mol%)、ZnOを0〜30(mol%)の範囲内、例えば3.0(mol%)、ZrO2を0〜1.0(mol%)の範囲内、例えば0(mol%)、P2O5を0〜6(mol%)の範囲内、例えば1.0(mol%)の割合でそれぞれ含む鉛ガラスである。また、上記鉛ガラスにおいて、PbO、SiO2、TiO2は、Pb/(Si+Ti)モル比が0.2〜2.4の範囲内、例えば1.10の割合となるように含まれている。 The above thick film conductor is made of thick film silver containing, for example, 6.0 parts by weight of glass in a range of 1 to 10 parts by weight of glass with respect to 100 parts by weight of Ag. within the 6-62 of (mol%), for example 39.0 (mol%), the range of the B 2 O 3 1~18 (mol% ), for example, 8.0 (mol%), the SiO 2 8~49 (mol in the range of%), for example 31.0 (mol%), in the range of Al 2 O 3 of 0 to 30 (mol%), for example, 3.0 (mol%), the Li 2 O in the range of 1 to 30 (mol%) , for example, 12.0 (mol%), a TiO 2 in the range of 1 to 30 (mol%), for example, 3.0 (mol%), in the range of ZnO 0 to 30 of (mol%), for example, 3.0 (mol%), ZrO within 2 0-1.0 of (mol%), for example, 0 (mol%), the P 2 O 5 in the range of 0~6 (mol%), lead glass containing each at a rate of for example 1.0 (mol%) is there. In the lead glass, PbO, SiO 2 , and TiO 2 are included so that the Pb / (Si + Ti) molar ratio is in the range of 0.2 to 2.4, for example, 1.10.

また、上記の導体層の厚さ寸法は例えば20〜30(μm)の範囲内、例えば25(μm)程度で、細線部の各々の幅寸法は例えば80〜130(μm)の範囲内、例えば100(μm)程度で、十分に高い導電性を備えている。   In addition, the thickness dimension of the conductor layer is, for example, in the range of 20-30 (μm), for example, about 25 (μm), and the width dimension of each thin wire portion is, for example, in the range of 80-130 (μm), for example, It is about 100 (μm) and has sufficiently high conductivity.

また、前記の裏面電極３０は、ｐ+層２４上にアルミニウムを導体成分とする厚膜材料を略全面に塗布して形成された全面電極３４と、その全面電極３４上に帯状に塗布して形成された厚膜銀から成る帯状電極３６とから構成されている。この帯状電極３６は、裏面電極３０に半田リボン３８や導線等を半田付け可能にするために設けられたものである。前記受光面電極２８にも裏面側と同様に半田リボン３８が溶着されている。 The back electrode 30 is formed by applying a full-surface electrode 34 formed by applying a thick film material containing aluminum as a conductor component on the p + layer 24 over substantially the entire surface, and a strip-like application on the full-surface electrode 34. The band-shaped electrode 36 made of thick silver is formed. The strip electrode 36 is provided in order to make it possible to solder a solder ribbon 38 or a conductive wire to the back electrode 30. A solder ribbon 38 is welded to the light receiving surface electrode 28 in the same manner as the back surface side.

本実施例の太陽電池１０は、受光面電極２８が前述したようにPbOを6〜62(mol%)の範囲内、B2O3を1〜18(mol%)の範囲内、SiO2を8〜49(mol%)の範囲内、Al2O3を0〜30(mol%)の範囲内、Li2Oを1〜30(mol%)の範囲内、TiO2を1〜30(mol%)の範囲内、ZnOを0〜30(mol%)の範囲内、ZrO2を0〜1.0(mol%)の範囲内、P2O5を0〜6(mol%)の範囲内の割合でそれぞれ含む組成の鉛ガラスを、銀100重量部に対して1〜10重量部の範囲で含む厚膜銀で構成されていることから、侵食量が80〜90(nm)程度すなわち反射防止膜２６の厚さ寸法よりも最大で10(nm)程度だけ大きい深さに制御されているので、線幅が100(μm)程度に細くされているにも拘わらず、ｎ層２２との間で良好なオーミックコンタクトが得られ、接触抵抗が低くなっている。 Solar cell 10 of the embodiment, the range of the PbO 6~62 (mol%) as the light-receiving surface electrode 28 described above, the range of the B 2 O 3 1~18 (mol% ), the SiO 2 8-49 within the range of (mol%), Al 2 O 3 within the range of 0~30 (mol%), in the range of Li 2 O and 1~30 (mol%), a TiO 2 1 to 30 (mol in the range of%), the proportion of the range within the range of the ZnO 0 to 30 (mol%), in the range of ZrO 2 and 0~1.0 (mol%), P 2 O 5 to Less than six (mol%) Is composed of thick film silver containing 1 to 10 parts by weight of lead glass having a composition of 1 to 10 parts by weight with respect to 100 parts by weight of silver. Since the depth is controlled to a depth that is about 10 (nm) larger than the thickness dimension of 26, the line width is reduced to about 100 (μm), but between the n layer 22 Good ohmic contact is obtained and contact resistance is low.

しかも、本実施例の受光面電極２８は、前述したようにガラス量が1〜10重量部程度と少量にされていることから高い導電性を有しているため、膜厚および線幅が何れも小さくされているにも拘わらずライン抵抗が低いので、接触抵抗が低いことと相俟って太陽電池１０の光電変換効率が高められている。   In addition, since the light receiving surface electrode 28 of the present embodiment has high conductivity since the glass amount is as small as about 1 to 10 parts by weight as described above, the film thickness and the line width can be any. Although the line resistance is low, the photoelectric conversion efficiency of the solar cell 10 is enhanced in combination with the low contact resistance.

上記のような受光面電極２８は、例えば、導体粉末と、ガラスフリットと、ベヒクルと、溶剤とから成る電極用ペーストを用いて良く知られたファイヤースルー法によって形成されたものである。その受光面電極形成を含む太陽電池１０の製造方法の一例を以下に説明する。   The light receiving surface electrode 28 as described above is formed, for example, by a well-known fire-through method using an electrode paste composed of conductive powder, glass frit, vehicle, and solvent. An example of the manufacturing method of the solar cell 10 including the formation of the light receiving surface electrode will be described below.

まず、上記ガラスフリットを作製する。Ti源として酸化チタン TiO2を、Li源として炭酸リチウム Li2CO3を、Al源として酸化アルミニウム Al2O3を、P源としてリン酸二水素アンモニウム NH4H2PO4を、Si源として二酸化珪素 SiO2を、B源として硼酸 B2O3を、Pb源として鉛丹 Pb3O4をそれぞれ用意し、前述した範囲内の適宜の組成となるように秤量して調合する。これを坩堝に投入して組成に応じた900〜1250(℃)の範囲内の温度で、30分〜1時間程度溶融し、急冷することでガラス化させる。このガラスを遊星ミルやボールミル等の適宜の粉砕装置を用いて粉砕する。粉砕後の平均粒径(D50)は例えば0.3〜3.0(μm)程度である。なお、上記ガラス粉末の平均粒径は前述した空気透過法を用いて算出したものである。 First, the glass frit is produced. Titanium oxide TiO 2 as Ti source, lithium carbonate Li 2 CO 3 as Li source, aluminum oxide Al 2 O 3 as Al source, ammonium dihydrogen phosphate NH 4 H 2 PO 4 as P source, Si source Prepare silicon dioxide SiO 2 , boric acid B 2 O 3 as a B source, and lead Pb 3 O 4 as a Pb source, and weigh and prepare them to have an appropriate composition within the above-mentioned range. This is put into a crucible, melted at a temperature in the range of 900 to 1250 (° C.) according to the composition for about 30 minutes to 1 hour, and rapidly cooled to be vitrified. This glass is pulverized using an appropriate pulverizing apparatus such as a planetary mill or a ball mill. The average particle size (D50) after pulverization is, for example, about 0.3 to 3.0 (μm). In addition, the average particle diameter of the said glass powder is computed using the air permeation method mentioned above.

一方、導体粉末として、例えば、平均粒径(D50)が0.3〜3.0(μm)の範囲内の市販の球状の銀粉末を用意する。このような平均粒径が十分に小さい銀粉末を用いることにより、塗布膜における銀粉末の充填率を高め延いては導体の導電率を高めることができる。また、前記ベヒクルは、有機溶剤に有機結合剤を溶解させて調製したもので、有機溶剤としては、例えばブチルカルビトールアセテートが、有機結合剤としては、例えばエチルセルロースが用いられる。ベヒクル中のエチルセルロースの割合は例えば15(wt%)程度である。また、ベヒクルとは別に添加する溶剤は、例えばブチルカルビトールアセテートである。すなわち、これに限定されるものではないが、ベヒクルに用いたものと同じ溶剤でよい。この溶剤は、ペーストの粘度調整の目的で添加される。   On the other hand, as the conductor powder, for example, a commercially available spherical silver powder having an average particle diameter (D50) in the range of 0.3 to 3.0 (μm) is prepared. By using such silver powder having a sufficiently small average particle diameter, the filling rate of the silver powder in the coating film can be increased and the electrical conductivity of the conductor can be increased. The vehicle is prepared by dissolving an organic binder in an organic solvent. For example, butyl carbitol acetate is used as the organic solvent, and ethyl cellulose is used as the organic binder. The ratio of ethyl cellulose in the vehicle is, for example, about 15 (wt%). A solvent added separately from the vehicle is, for example, butyl carbitol acetate. That is, although it is not limited to this, the same solvent as that used for the vehicle may be used. This solvent is added for the purpose of adjusting the viscosity of the paste.

以上のペースト原料をそれぞれ用意して、例えば導体粉末を77〜88(wt%)の範囲内、ガラスフリットを1〜10(wt%)の範囲内、ベヒクルを8〜14(wt%)の範囲内、溶剤を2〜5(wt%)の範囲内の割合で秤量し、攪拌機等を用いて混合した後、例えば三本ロールミルで分散処理を行う。これにより、前記電極用ペーストが得られる。ペーストの粘度は、20(rpm)、25(℃)の条件下で180〜230(Pa・s)の範囲内となるように調製した。   Prepare the above paste materials, for example, conductor powder in the range of 77-88 (wt%), glass frit in the range of 1-10 (wt%), vehicle in the range of 8-14 (wt%) Among these, the solvent is weighed at a ratio in the range of 2 to 5 (wt%), mixed using a stirrer or the like, and then subjected to a dispersion treatment using, for example, a three roll mill. Thereby, the electrode paste is obtained. The viscosity of the paste was adjusted to be in the range of 180 to 230 (Pa · s) under the conditions of 20 (rpm) and 25 (° C.).

上記のようにして電極用ペーストを調製する一方、適宜のシリコン基板に例えば、熱拡散法やイオンプランテーション等の良く知られた方法で不純物を拡散し或いは注入して前記ｎ層２２およびｐ+層２４を形成することにより、前記シリコン基板２０を作製する。次いで、これに例えばＰＥ−ＣＶＤ(プラズマＣＶＤ)等の適宜の方法で窒化珪素薄膜を形成し、前記反射防止膜２６を設ける。 While preparing the electrode paste as described above, the n layer 22 and the p + layer are diffused or implanted into an appropriate silicon substrate by a well-known method such as a thermal diffusion method or ion plantation. By forming 24, the silicon substrate 20 is produced. Next, a silicon nitride thin film is formed thereon by an appropriate method such as PE-CVD (plasma CVD), and the antireflection film 26 is provided.

次いで、上記の反射防止膜２６上に前記図２に示すパターンで前記電極用ペーストをスクリーン印刷する。これを例えば150(℃)で乾燥し、更に、近赤外炉において700〜800(℃)の範囲内の温度で焼成処理を施す。これにより、その焼成過程で電極用ペースト中のガラス成分が反射防止膜２６を溶かし、その電極用ペーストが反射防止膜２６を破るので、電極用ペースト中の導体成分すなわち銀とｎ層２２との電気的接続が得られ、前記図１に示されるようにシリコン基板２０と受光面電極２８とのオーミックコンタクトが得られる。受光面電極２８は、このようにして形成される。   Next, the electrode paste is screen-printed on the antireflection film 26 with the pattern shown in FIG. This is dried at, for example, 150 (° C.), and further subjected to a baking treatment at a temperature in the range of 700 to 800 (° C.) in a near infrared furnace. As a result, the glass component in the electrode paste melts the antireflection film 26 in the firing process, and the electrode paste breaks the antireflection film 26. Therefore, the conductor component in the electrode paste, that is, silver and the n layer 22 Electrical connection is obtained, and an ohmic contact between the silicon substrate 20 and the light-receiving surface electrode 28 is obtained as shown in FIG. The light receiving surface electrode 28 is formed in this way.

なお、前記裏面電極３０は、上記工程の後に形成してもよいが、受光面電極２８と同時に焼成して形成することもできる。裏面電極３０を形成するに際しては、上記シリコン基板２０の裏面全面に、例えばアルミニウムペーストをスクリーン印刷法等で塗布し、焼成処理を施すことによってアルミニウム厚膜から成る前記全面電極３４を形成する。更に、その全面電極３４の表面に前記電極用ペーストをスクリーン印刷法等を用いて帯状に塗布して焼成処理を施すことによって、前記帯状電極３６を形成する。これにより、裏面全面を覆う全面電極３４と、その表面の一部に帯状に設けられた帯状電極３６とから成る裏面電極３０が形成され、前記の太陽電池１０が得られる。上記工程において、同時焼成で製造する場合には、受光面電極２８の焼成前に印刷処理を施すことになる。   The back electrode 30 may be formed after the above process, but may be formed by firing at the same time as the light receiving surface electrode 28. When the back electrode 30 is formed, the full surface electrode 34 made of a thick aluminum film is formed on the entire back surface of the silicon substrate 20 by, for example, applying an aluminum paste by screen printing or the like and performing a baking process. Further, the strip electrode 36 is formed by applying the electrode paste on the surface of the entire surface electrode 34 in a strip shape by screen printing or the like and performing a baking treatment. Thereby, the back electrode 30 which consists of the full surface electrode 34 which covers the whole back surface, and the strip | belt-shaped electrode 36 provided in strip shape on a part of the surface is formed, and the said solar cell 10 is obtained. In the above process, when manufacturing by simultaneous firing, a printing process is performed before firing the light-receiving surface electrode 28.

次に、ガラス組成を種々変更して、上記の製造工程に従って太陽電池１０を製造して評価した結果を説明する。太陽電池特性については、市販のソーラーシミュレータを用いてその出力を測定して、曲線因子ＦＦ値およびリーク電流Idを求めた。また、Rcはｎ層２２と受光面電極(Ag電極)２８との間の接触抵抗で、Transfer Length Method(TLM)法を用いて以下のようにして求めた。すなわち、先ず、前記製造工程における受光面電極２８の形成と同様にして、複数本の帯状のオーミック電極を互いに平行且つ相互間隔が各々異なるようにｎ層上にファイヤースルーによって形成する。形成した電極パターンを図３(ａ)、(ｂ)に示す。次いで、形成した各電極対間の電気抵抗を４端子法を用いて測定する。測定した電気抵抗を、電極間隔を横軸(ｘ軸)にとり、電気抵抗測定値を縦軸(ｙ軸)にとった座標上に記すと、図４に示すように記した点から得られる近似的な一次直線のｙ切片が2Rcになる。図５はこの測定原理を説明したもので、測定された抵抗値をRtotal、電極対間のシート抵抗をRsheet、電極間隔をdとしたとき、以下の関係式が成り立つので、図４のグラフにおけるｙ切片が2Rcになる。
Rtotal＝2Rc＋Rsheet・d
なお、グラフの傾きがRsheetである。また、ｘ切片は遷移長Ltと称され、これは電極下で電気的な接触に影響を与えている領域として定義される。また、上記のRc、Lt、およびオーミック電極の長さから固有接触抵抗ρcを算出できる。 Next, the result of having manufactured and evaluated the solar cell 10 according to said manufacturing process by changing glass composition variously is demonstrated. About the solar cell characteristic, the output was measured using the commercially available solar simulator, and the fill factor FF value and the leakage current Id were obtained. Rc is the contact resistance between the n layer 22 and the light-receiving surface electrode (Ag electrode) 28, and was determined using the Transfer Length Method (TLM) method as follows. That is, first, in the same manner as the formation of the light-receiving surface electrode 28 in the manufacturing process, a plurality of strip-shaped ohmic electrodes are formed on the n layer by fire-through so as to be mutually parallel and mutually different. The formed electrode pattern is shown in FIGS. Next, the electrical resistance between the formed electrode pairs is measured using a four-terminal method. When the measured electrical resistance is written on the coordinates with the electrode interval taken on the horizontal axis (x-axis) and the measured electrical resistance value taken on the vertical axis (y-axis), the approximation obtained from the points shown in FIG. The y-intercept of a typical primary line is 2Rc. FIG. 5 illustrates this measurement principle. When the measured resistance value is Rtotal, the sheet resistance between the electrode pairs is Rsheet, and the electrode interval is d, the following relational expression is established. The y-intercept is 2Rc.
Rtotal = 2Rc + Rsheet · d
Note that the slope of the graph is Rsheet. The x-intercept is referred to as a transition length Lt, which is defined as a region that affects electrical contact under the electrode. Further, the specific contact resistance ρc can be calculated from the above Rc, Lt, and the length of the ohmic electrode.

上記評価結果を、ガラス組成と併せて表１に示す。表１において、No.欄の数字に△を付したものが本発明の範囲外の比較例であり、他が本発明の範囲内の実施例である。すなわち、No.5，7，14，18〜20，25，28，33，35，39，42，46，48，49が比較例、他が実施例である。これらの実施例のうち、No.欄の数字に○を付したもの(No.8，11，12，21，23，24，29，32)は、後述するように本発明の範囲内の最適組成であり、中でも特に好ましいもの(No.12，21，24，29，32)に◎を付した。ＦＦ値は良好なオーミックコンタクトが得られているか否かの判定であり、一般に、太陽電池はＦＦ値が70以上であれば使用可能とされているが、高いほど好ましいのはもちろんであり、本実施例においては、ＦＦ値が75より大きいものを合格とした。また、リーク電流Idはｐｎ接合に電極の侵入が起きたか否かの判定基準となるもので、低い方が好ましいが、-10(V)で1.0(A)以下であれば使用可能であるので、0.2(A)以下を◎、0.5(A)以下を○、1.0(A)以下を△、1.0(A)超を×とした。また、固有接触抵抗ρcはＦＦ値の低下要因の一つであって、低い方が好ましいものの、ρcが低くとも必ずしも高いＦＦ値が得られないが、種々のＦＦ値低下要因のうちの一つを排除した状態でガラス組成を評価することや、Ti添加の効果を確認する目的で掲載している。
The evaluation results are shown in Table 1 together with the glass composition. In Table 1, the numbers in the No. column marked with Δ are comparative examples outside the scope of the present invention, and the others are examples within the scope of the present invention. That is, Nos. 5, 7, 14, 18 to 20, 25, 28, 33, 35, 39, 42, 46, 48, and 49 are comparative examples, and others are examples. Among these examples, those marked with a circle in the No. column (Nos. 8, 11, 12, 21, 23, 24, 29, 32) are optimal within the scope of the present invention as described later. The composition is particularly preferable (Nos. 12, 21, 24, 29, 32). The FF value is a determination as to whether or not a good ohmic contact is obtained. In general, a solar cell can be used if the FF value is 70 or more. In the examples, those having an FF value greater than 75 were considered acceptable. The leak current Id is a criterion for determining whether or not an electrode has entered the pn junction, and is preferably lower, but can be used if it is -10 (V) or less than 1.0 (A). , 0.2 (A) or less was evaluated as ◎, 0.5 (A) or less as ◯, 1.0 (A) or less as Δ, and over 1.0 (A) as ×. In addition, the specific contact resistance ρc is one of the factors for lowering the FF value, and although a lower one is preferable, a high FF value is not necessarily obtained even if ρc is low, but it is one of various FF value lowering factors. It has been published for the purpose of evaluating the glass composition in a state in which is excluded, and confirming the effect of Ti addition.

Figure 2013120807
Figure 2013120807

なお、各試料は平均粒径1.6(μm)の球状のAg粉と平均粒径1.5(μm)のガラスフリットとを用いて作製した。調合割合はAg粉 83(wt%)、ガラスフリット 4(wt%)、ベヒクル 8(wt%)、溶剤 5(wt%)を基本とし、印刷性を同等とするために、25(℃)−20(rpm)における粘度が180〜230(Pa・s)になるようにベヒクル量および溶剤量を調整した。また、受光面電極２８を形成する際の印刷製版は、線径23(μm)のSUS325製スクリーンメッシュに20(μm)厚の乳剤を設けたものとした。また、グリッドラインの幅寸法が100(μm)となるように印刷条件を設定した。また、基板のｎ層のシート抵抗は90±10(Ω/□)である。   Each sample was prepared using spherical Ag powder having an average particle size of 1.6 (μm) and glass frit having an average particle size of 1.5 (μm). The mixing ratio is based on Ag powder 83 (wt%), glass frit 4 (wt%), vehicle 8 (wt%), solvent 5 (wt%), and 25 (° C) − The amount of vehicle and the amount of solvent were adjusted so that the viscosity at 20 (rpm) would be 180 to 230 (Pa · s). The printing plate making for forming the light-receiving surface electrode 28 was made by providing a 20 (μm) thick emulsion on a SUS325 screen mesh having a wire diameter of 23 (μm). The printing conditions were set so that the width of the grid line was 100 (μm). The sheet resistance of the n layer of the substrate is 90 ± 10 (Ω / □).

上記表１には、実施例として、基本骨格を構成するPbO-B2O3-SiO2にAl2O3、Li2O、TiO2、ZnO、ZrO2、P2O5が添加されたPbO-B2O3-SiO2-Al2O3-Li2O-TiO2-ZnO-ZrO2-P2O5の９成分系と、これらのうち幾つかの元素を欠く４成分系〜８成分系のガラスが示されている。本願発明では、Pb、B、Si、Li、Tiの５つの元素が必須成分であり、実施例はこれら５成分から成り、或いはこれらに加えて他の４成分のうちの１〜４種を含む組成を有する。 In Table 1, Al 2 O 3 , Li 2 O, TiO 2 , ZnO, ZrO 2 , and P 2 O 5 were added to PbO—B 2 O 3 —SiO 2 constituting the basic skeleton as an example. 9 component system of PbO-B 2 O 3 —SiO 2 —Al 2 O 3 —Li 2 O—TiO 2 —ZnO—ZrO 2 —P 2 O 5 and 4 component system lacking some of these elements An 8-component glass is shown. In the present invention, five elements of Pb, B, Si, Li, and Ti are essential components, and the examples are composed of these five components, or in addition to these, include one to four of the other four components. Having a composition.

No.1〜4は、Li量の上限を確認したものである。Pbが9.0〜17.0(mol%)、Bが12.0(mol%)、Siが15.0(mol%)、Alが6.0(mol%)、Liが25.0〜30.0(mol%)、Tiが15.0(mol%)、Znが7.0〜13.0(mol%)、ZrおよびPが0(mol%)、Pb/(Si+Ti)が0.3〜0.6の範囲内の組成では、何れもＦＦ値が77と極めて高い特性が得られた。No.4はLi量を上限近傍でNo.1〜3よりも少なくして変化を確かめたものである。また、IdはPbが多くなるほど、すなわちPb/(Si+Ti)が大きくなるほど増大する傾向があるが、No.3,4を対比すると、No.4ではIdが0.5(A)以下に抑えられているので、Liを減じ、Znを増すとこの傾向が緩和されるものと考えられる。また、ρcは0.008〜0.010(Ω・cm2)と十分に低い値であった。これらの評価結果によれば、他の元素、特にPb量との兼ね合いもあるが、Liは30.0(mol%)以下の範囲で含むことができる。 Nos. 1 to 4 confirm the upper limit of the Li amount. Pb 9.0-17.0 (mol%), B 12.0 (mol%), Si 15.0 (mol%), Al 6.0 (mol%), Li 25.0-30.0 (mol%), Ti 15.0 (mol%) ), Zn is 7.0 to 13.0 (mol%), Zr and P are 0 (mol%), and Pb / (Si + Ti) is within the range of 0.3 to 0.6. was gotten. No. 4 was confirmed by changing the amount of Li less than No. 1 to 3 near the upper limit. In addition, Id tends to increase as Pb increases, that is, Pb / (Si + Ti) increases, but when comparing No. 3 and 4, Id can be suppressed to 0.5 (A) or less in No. 4. Therefore, it is considered that this tendency is alleviated by reducing Li and increasing Zn. Moreover, ρc was a sufficiently low value of 0.008 to 0.010 (Ω · cm 2 ). According to these evaluation results, Li can be contained in a range of 30.0 (mol%) or less, although there is a balance with the amount of other elements, particularly Pb.

No.5は、No.10と併せて必須５成分の組成でSi量の上限を確認したもので、Pbが29.5〜46.0(mol%)、Bが1.0〜14.6(mol%)、Siが49.0〜51.2(mol%)、Alが0(mol%)、Liが3.0〜3.7(mol%)、Tiが1.0(mol%)、Zn、ZrおよびPが0(mol%)、Pb/(Si+Ti)が0.6〜0.9の範囲内の組成では、No.10に示されるようにSiが49.0(mol%)でＦＦ値が76、Idが1.0(A)以下の十分な特性が得られたが、No.5に示されるようにSiが51.2(mol%)になるとＦＦ値が36と著しく低下し、Idも1.0(A)超と大きくなった。この評価結果によれば、Siの上限は49.0(mol%)と考えられる。すなわち、Ti量が適切であっても、Si量が過剰ではＦＦ値が低くなる。なお、Al、Pを含む７成分系であるが、No.49もSi量の上限を超えた組成であり、ＦＦ値が44と低い結果となった。   No. 5 was confirmed with the composition of five essential components in combination with No. 10 and confirmed the upper limit of Si content. Pb was 29.5-46.0 (mol%), B was 1.0-14.6 (mol%), Si was 49.0 ~ 51.2 (mol%), Al is 0 (mol%), Li is 3.0 to 3.7 (mol%), Ti is 1.0 (mol%), Zn, Zr and P are 0 (mol%), Pb / (Si + In the composition where Ti) is in the range of 0.6 to 0.9, as shown in No. 10, sufficient characteristics were obtained in which Si was 49.0 (mol%), FF value was 76, and Id was 1.0 (A) or less. As shown in No. 5, when Si was 51.2 (mol%), the FF value was significantly reduced to 36, and Id was also increased to more than 1.0 (A). According to this evaluation result, the upper limit of Si is considered to be 49.0 (mol%). That is, even if the Ti amount is appropriate, if the Si amount is excessive, the FF value becomes low. In addition, although it is a 7-component system including Al and P, No. 49 also has a composition exceeding the upper limit of the Si amount, and the FF value was as low as 44.

No.7は、前記No.1〜3と併せてLi量の上限を確認したもので、Pbが29.0(mol%)、Bが4.0(mol%)、Siが20.0(mol%)、Alが0(mol%)、Liが35.0(mol%)、Tiが12.0(mol%)、Zn、ZrおよびPが0(mol%)、Pb/(Si+Ti)が0.9の組成では、ＦＦ値が73に留まり不十分な結果であった。Tiはρcを低くしてＦＦ値を高める効果が認められるが、ドナー元素であるLiが過剰になると、ρcは低くなってもＦＦ値が低くなって、Ti添加効果を十分に享受することができない。ｎ層にLiが過剰に拡散し、電子の再結合が促進されるためと考えられる。この結果および前記No.1〜3の結果から、Li量の上限は30.0(mol%)である。   No. 7 confirmed the upper limit of Li amount together with No. 1 to 3, Pb 29.0 (mol%), B 4.0 (mol%), Si 20.0 (mol%), Al is In the composition of 0 (mol%), Li 35.0 (mol%), Ti 12.0 (mol%), Zn, Zr and P 0 (mol%), Pb / (Si + Ti) 0.9, the FF value is The result was insufficient. Ti has the effect of lowering ρc and increasing the FF value. However, when Li as the donor element is excessive, the FF value is lowered even if ρc is lowered, and the Ti addition effect can be fully enjoyed. Can not. This is presumably because Li diffuses excessively in the n layer, and recombination of electrons is promoted. From this result and the results of Nos. 1 to 3, the upper limit of the Li amount is 30.0 (mol%).

No.14は、No.31と併せてP量の上限を確認したもので、Pbが38.6〜45.0(mol%)、Bが6.0〜7.9(mol%)、Siが24.0〜28.5(mol%)、Alが0.5〜6.0(mol%)、Liが12.0(mol%)、Tiが1.0〜3.0(mol%)、Znが0(mol%)、Zrが0〜0.5(mol%)、Pが6.0〜9.0(mol%)、Pb/(Si+Ti)が1.2〜1.8の範囲内の組成では、No.31に示されるようにP量が6.0(mol%)でＦＦ値が76、Idが0.5(A)以下の十分な特性が得られたが、No.14に示されるようにP量が9.0(mol%)ではＦＦ値が68に留まり不十分な結果となった。P量が過剰になる場合も、Liが過剰になる場合と同様に、電子の再結合が促進されるためと考えられる。これらの結果によれば、P量の上限は6.0(mol%)である。   No.14 was confirmed the upper limit of P amount together with No.31, Pb 38.6-45.0 (mol%), B 6.0-7.9 (mol%), Si 24.0-28.5 (mol%) Al is 0.5 to 6.0 (mol%), Li is 12.0 (mol%), Ti is 1.0 to 3.0 (mol%), Zn is 0 (mol%), Zr is 0 to 0.5 (mol%), and P is 6.0. -9.0 (mol%), Pb / (Si + Ti) in the range of 1.2-1.8, as shown in No. 31, P amount is 6.0 (mol%), FF value is 76, Id is 0.5 (A) The following sufficient characteristics were obtained. However, as shown in No. 14, when the P content was 9.0 (mol%), the FF value remained at 68, resulting in an insufficient result. It is considered that when the amount of P is excessive, recombination of electrons is promoted as in the case where Li is excessive. According to these results, the upper limit of the amount of P is 6.0 (mol%).

No.16は、No.18と併せて必須５成分系でB量の上限を確認したもので、Pbが37.0〜38.0(mol%)、Bが18.0〜21.0(mol%)、Siが15.0〜17.0(mol%)、Alが0(mol%)、Liが12.0(mol%)、Tiが15.0(mol%)、Zn、Zr、およびPが0(mol%)、Pb/(Si+Ti)が1.2の範囲内の組成では、No.16に示されるようにB量が18.0(mol%)でＦＦ値が76、Idが0.5(A)以下の十分な特性が得られたが、No.18に示されるようにB量が21.0(mol%)ではＦＦ値が74に留まり不十分な結果となった。これらの結果によれば、B量の上限は18.0(mol%)である。なお、No.13はB量を上限近傍でNo.16よりも少なくして変化を確かめたもので、同程度の結果が得られている。   No.16 is the essential 5 component system together with No.18 and confirmed the upper limit of B amount. Pb is 37.0 to 38.0 (mol%), B is 18.0 to 21.0 (mol%), Si is 15.0 to 17.0 (mol%), Al 0 (mol%), Li 12.0 (mol%), Ti 15.0 (mol%), Zn, Zr, and P 0 (mol%), Pb / (Si + Ti) In the composition within the range of 1.2, as shown in No. 16, sufficient characteristics were obtained in which the B amount was 18.0 (mol%), the FF value was 76, and Id was 0.5 (A) or less. As shown in FIG. 18, when the B content was 21.0 (mol%), the FF value remained at 74, which was insufficient. According to these results, the upper limit of the amount of B is 18.0 (mol%). Note that No. 13 was confirmed by confirming the change by reducing the B amount in the vicinity of the upper limit than No. 16, and a similar result was obtained.

No.17は、No.10やNo.25、28と併せてTi量の下限を確認したもので、５成分系〜９成分系の種々の組成において、No.10、17に示されるようにTi量が1.0(mol%)であれば、76以上のＦＦ値と1.0(A)以下のIdが得られることが確かめられた。これに対して、Tiを欠くNo.25、28では、ＦＦ値が72〜74に留まった。これらの結果によれば、Ti量の下限は1.0(mol%)である。   No.17 is a combination of No.10, No.25, and 28 that confirms the lower limit of Ti amount. As shown in No.10 and 17 in various compositions of 5 to 9 components, It was confirmed that when the Ti amount was 1.0 (mol%), an FF value of 76 or more and an Id of 1.0 (A) or less were obtained. On the other hand, in No. 25 and 28 which lack Ti, FF value stayed at 72-74. According to these results, the lower limit of the Ti amount is 1.0 (mol%).

No.19は、No.24と併せて５成分系でSi量の下限およびTi量の上限を確認したもので、No.24に示されるようにPbが48.0〜50.0(mol%)、Bが6.0(mol%)、Siが5.0〜8.0(mol%)、Alが0(mol%)、Liが6.0(mol%)、Tiが30.0〜35.0(mol%)、Zn、Zr、およびPが0(mol%)、Pb/(Si+Ti)が1.2〜1.3の範囲内の組成では、Si量が8.0(mol%)、Ti量が30.0(mol%)でＦＦ値が78、Idが0.2(A)以下の極めて高い特性が得られたが、No.19に示されるようにSi量が5.0(mol%)、Ti量が35.0(mol%)ではガラスフリット製造の際にガラス原料が熔融せず、評価不能であった。これらの結果によれば、Si量の下限は8.0(mol%)、Ti量の上限は30.0(mol%)である。   No. 19 is a five-component system in which the lower limit of Si content and the upper limit of Ti content were confirmed together with No. 24. As shown in No. 24, Pb was 48.0-50.0 (mol%), B was 6.0 (mol%), Si 5.0-8.0 (mol%), Al 0 (mol%), Li 6.0 (mol%), Ti 30.0-35.0 (mol%), Zn, Zr, and P 0 (mol%), Pb / (Si + Ti) in the range of 1.2 to 1.3, Si amount 8.0 (mol%), Ti amount 30.0 (mol%), FF value 78, Id 0.2 ( A) The following extremely high characteristics were obtained, but as shown in No. 19, when the Si content was 5.0 (mol%) and the Ti content was 35.0 (mol%), the glass raw material melted during the production of the glass frit. It was impossible to evaluate. According to these results, the lower limit of Si content is 8.0 (mol%), and the upper limit of Ti content is 30.0 (mol%).

No.20は、No.10、22と併せて５成分系でB量の下限を確認したもので、Pbが46.0〜54.0(mol%)、Bが0〜1.0(mol%)、Siが23.0〜49.0(mol%)、Alが0(mol%)、Liが3.0〜12.0(mol%)、Tiが1.0〜15.0(mol%)、Zn、Zr、およびPが0(mol%)、Pb/(Si+Ti)が0.9〜1.3の範囲内の組成では、No.10、22に示されるようにB量が1.0(mol%)でＦＦ値が76〜77、Idが1.0(A)以下の高い特性が得られたが、No.20に示されるようにB量が0(mol%)ではＦＦ値が71に留まった。これらの結果によれば、B量の下限は1.0(mol%)である。   No. 20 is a five-component system in which the lower limit of B content has been confirmed together with No. 10 and No. 22, Pb is 46.0-54.0 (mol%), B is 0-1.0 (mol%), Si is 23.0 ~ 49.0 (mol%), Al is 0 (mol%), Li is 3.0 to 12.0 (mol%), Ti is 1.0 to 15.0 (mol%), Zn, Zr, and P are 0 (mol%), Pb / In the composition where (Si + Ti) is in the range of 0.9 to 1.3, as shown in No. 10 and 22, the amount of B is 1.0 (mol%), the FF value is 76 to 77, and Id is 1.0 (A) or less. Although high characteristics were obtained, as shown in No. 20, the FF value remained at 71 when the B amount was 0 (mol%). According to these results, the lower limit of the amount of B is 1.0 (mol%).

No.32は、No.39と併せてLi量の下限を確認したもので、Pbが51.0〜58.5(mol%)、Bが4.0〜10.0(mol%)、Siが25.0〜28.0(mol%)、Alが0〜3.0(mol%)、Liが0〜1.0(mol%)、Tiが3.0〜10.0(mol%)、Znが0〜4.0(mol%)、Zrが0〜0.5(mol%)、Pが0〜2.0(mol%)、Pb/(Si+Ti)が1.5〜1.9の範囲内の組成では、No.32に示されるようにLi量が1.0(mol%)でＦＦ値が78、Idが0.2(A)以下の極めて高い特性が得られたが、No.39に示されるようにLi量が0(mol%)ではＦＦ値が74に留まり、Idも1.0(A)超となった。これらの結果によれば、Li量の下限は1.0(mol%)である。   No.32 was confirmed the lower limit of Li amount together with No.39, Pb is 51.0-58.5 (mol%), B is 4.0-0.0 (mol%), Si is 25.0-28.0 (mol%) Al is 0 to 3.0 (mol%), Li is 0 to 1.0 (mol%), Ti is 3.0 to 10.0 (mol%), Zn is 0 to 4.0 (mol%), Zr is 0 to 0.5 (mol%) , P in the range of 0 to 2.0 (mol%) and Pb / (Si + Ti) in the range of 1.5 to 1.9, as shown in No. 32, the Li amount is 1.0 (mol%) and the FF value is 78. , Id obtained an extremely high characteristic of 0.2 (A) or less, but as shown in No. 39, when the Li amount was 0 (mol%), the FF value remained at 74, and Id was over 1.0 (A). became. According to these results, the lower limit of the Li amount is 1.0 (mol%).

No.33は、No.34、38、47、48と併せてPb量の上限を確認したもので、Pbが60.0〜64.0(mol%)、Bが1.0〜4.0(mol%)、Siが15.0〜30.0(mol%)、Alが0〜1.0(mol%)、Liが0〜6.0(mol%)、Tiが1.0〜15.0(mol%)、Znが0〜4.0(mol%)、Zrが0〜1.0(mol%)、Pが0〜2.0(mol%)、Pb/(Si+Ti)が1.9〜2.4の範囲内の組成では、No.34、47に示されるようにPb量が60.0〜62.0(mol%)でＦＦ値が76〜77、Idが1.0(A)以下の高い特性が得られたが、No.33、48に示されるようにPb量が63.0(mol%)以上ではＦＦ値が73以下に留まった。すなわち、Ti量が適切でも、Pb量が過剰ではＦＦ値が低くなる。これらの結果によれば、Pb量の上限は62.0(mol%)である。   No. 33 is a combination of No. 34, 38, 47, 48 and confirmed the upper limit of the amount of Pb, Pb 60.0-64.0 (mol%), B 1.0-4.0 (mol%), Si 15.0 -30.0 (mol%), Al 0-1.0 (mol%), Li 0-6.0 (mol%), Ti 1.0-15.0 (mol%), Zn 0-4.0 (mol%), Zr 0 -1.0 (mol%), P is 0 to 2.0 (mol%), and Pb / (Si + Ti) is in the range of 1.9 to 2.4. High characteristics with an FF value of 76-77 and Id of 1.0 (A) or less were obtained at 62.0 (mol%), but as shown in Nos. 33 and 48, FF values were higher than 63.0 (mol%). The value stayed below 73. That is, even if the Ti amount is appropriate, if the Pb amount is excessive, the FF value becomes low. According to these results, the upper limit of the amount of Pb is 62.0 (mol%).

No.34は、No.35と併せてPb/(Si+Ti)の上限を確認したもので、Pbが60.0〜62.0(mol%)、Bが4.0〜6.0(mol%)、Siが22.0〜25.0(mol%)、Alが0.5〜1.0(mol%)、Liが1.0(mol%)、Tiが1.0(mol%)、Znが4.0〜7.0(mol%)、Zrが0〜0.5(mol%)、Pが2.0(mol%)、Pb/(Si+Ti)が2.4〜2.6の範囲内の組成では、No.34に示されるようにPb/(Si+Ti)が2.4でＦＦ値が77、Idが1.0(A)以下の高い特性が得られたが、No.35に示されるようにPb/(Si+Ti)が2.6ではＦＦ値が73に留まった。これらの結果によれば、Pb/(Si+Ti)の上限は2.4である。なお、No.37はPb(Si+Ti)の上限近傍でNo.34よりも小さくして特性を確認したもので、リーク電流IdがNo.34よりも少なくなることから、Pb/(Si+Ti)は2.0以下に留める方が好ましい可能性がある。   No. 34 was confirmed with the upper limit of Pb / (Si + Ti) together with No. 35, Pb 60.0-62.0 (mol%), B 4.0-6.0 (mol%), Si 22.0- 25.0 (mol%), Al 0.5-1.0 (mol%), Li 1.0 (mol%), Ti 1.0 (mol%), Zn 4.0-7.0 (mol%), Zr 0-0.5 (mol%) ), P is 2.0 (mol%) and Pb / (Si + Ti) is in the range of 2.4 to 2.6, as shown in No. 34, Pb / (Si + Ti) is 2.4 and FF value is 77. , High characteristics with Id of 1.0 (A) or less were obtained, but as shown in No. 35, the FF value remained at 73 when Pb / (Si + Ti) was 2.6. According to these results, the upper limit of Pb / (Si + Ti) is 2.4. Note that No. 37 was confirmed to be smaller than No. 34 in the vicinity of the upper limit of Pb (Si + Ti), and the leakage current Id was smaller than No. 34, so Pb / (Si + It may be preferable to keep Ti) below 2.0.

No.41は、No.42、46と併せてPb量の下限およびPb/(Si+Ti)を確認したもので、Pbが3.0〜6.0(mol%)、Bが12.0(mol%)、Siが15.0(mol%)、Alが6.0(mol%)、Liが30.0(mol%)、Tiが15.0(mol%)、Znが16.0〜19.0(mol%)、Zr、Pが0(mol%)、Pb/(Si+Ti)が0.1〜0.2の範囲内の組成では、No.41に示されるようにPb量が6.0(mol%)、Pb/(Si+Ti)が0.2でＦＦ値が77、Idが0.2(A)以下の高い特性が得られたが、Pb量が3.0(mol%)ではＦＦ値が73に留まり(No.42)、Pb量が6.0(mol%)でもPb/(Si+Ti)が0.1ではＦＦ値が34に留まった(No.46)。すなわち、Ti量が適切でも、Pb/(Si+Ti)が過小ではＦＦ値が低くなる。これらの結果によれば、Pb量の下限は6.0(mol%)で、Pb/(Si+Ti)の下限は0.2である。   No. 41 was confirmed with the lower limit of Pb amount and Pb / (Si + Ti) in combination with No. 42 and No. 46, Pb 3.0-6.0 (mol%), B 12.0 (mol%), Si Is 15.0 (mol%), Al is 6.0 (mol%), Li is 30.0 (mol%), Ti is 15.0 (mol%), Zn is 16.0 to 19.0 (mol%), Zr, P is 0 (mol%) In the composition where Pb / (Si + Ti) is in the range of 0.1 to 0.2, as shown in No. 41, the amount of Pb is 6.0 (mol%), Pb / (Si + Ti) is 0.2, and the FF value is 77. However, when the Pb content is 3.0 (mol%), the FF value remains at 73 (No. 42), and even when the Pb content is 6.0 (mol%), Pb / ( When Si + Ti was 0.1, the FF value remained at 34 (No. 46). That is, even if the amount of Ti is appropriate, if the Pb / (Si + Ti) is too small, the FF value becomes low. According to these results, the lower limit of the amount of Pb is 6.0 (mol%), and the lower limit of Pb / (Si + Ti) is 0.2.

また、上記の評価結果を、成分系毎に見ると、No.5、7、9、10、15、16、18〜20、22〜24、29、30、33は、必須元素のみの５成分系(但し、No.20はBを欠く)で、Pbが29.0〜63.0(mol%)、Bが0〜21.0(mol%)、Siが5.0〜51.2(mol%)、Alが0(mol%)、Liが3.0〜35.0(mol%)、Tiが1.0〜35.0(mol%)、Zn、Zr、Pが0(mol%)の範囲内の組成では、Pbが35.0〜55.0(mol%)、Bが1.0〜18.0(mol%)、Siが8.0〜49.0(mol%)、Liが3.0〜24.0(mol%)、Tiが1.0〜30.0(mol%)、Pb(Si+Ti)が0.9〜1.7の範囲で、76〜78のＦＦ値および1.0(A)以下のIdが得られた。   In addition, when the above evaluation results are viewed for each component system, No.5, 7, 9, 10, 15, 16, 18-20, 22-24, 29, 30, 33 are only 5 essential elements. System (however, No. 20 lacks B), Pb is 29.0-63.0 (mol%), B is 0-21.0 (mol%), Si is 5.0-51.2 (mol%), Al is 0 (mol%) ), Li is 3.0 to 35.0 (mol%), Ti is 1.0 to 35.0 (mol%), Zn, Zr, and P is in the range of 0 (mol%), Pb is 35.0 to 55.0 (mol%), B is 1.0-18.0 (mol%), Si is 8.0-49.0 (mol%), Li is 3.0-24.0 (mol%), Ti is 1.0-30.0 (mol%), Pb (Si + Ti) is 0.9-1.7 In the range, an FF value of 76 to 78 and an Id of 1.0 (A) or less were obtained.

上記評価結果を個々の構成元素についてみると、Pbは35.0(mol%)含まれていればＦＦ値が77でIdが0.2(A)以下の高い特性が得られた(No.9)。また、55.0(mol%)ではＦＦ値が78でIdが0.2(A)以下の極めて高い特性が得られたが(No.29)、63.0(mol%)ではＦＦ値が73と不十分な結果に留まった(No.33)。Bは1.0(mol%)含まれていればＦＦ値が77でIdが0.2(A)以下の高い特性が得られるが(No.22)、これを欠くとＦＦ値が71に留まり不十分な結果となる(No.20)。また、18.0(mol%)ではＦＦ値が76でIdが0.5(A)以下の十分な特性が得られるが(No.16)、21.0(mol%)ではＦＦ値が74と不十分な結果になった(No.18)。Siは8.0(mol%)含まれていればＦＦ値が78でIdが0.2(A)以下の極めて高い特性が得られるが(No.24)、5.0(mol%)では電極材料が熔融してしまい、特性評価も不能な状態となった(No.19)。また、49.0(mol%)であればＦＦ値が76でIdが1.0(A)以下の十分な特性が得られるが(No.10)、51.2(mol%)ではＦＦ値が36まで低下すると共に1.0(A)超になって不十分な結果となった(No.5)。Liは3.0(mol%)でもＦＦ値が76、Idが1.0(A)以下の十分な特性が得られるが(No.10)、35.0(mol%)ではＦＦ値が73と不十分な結果となった(No.7)。24.0(mol%)ではＦＦ値が77、Idが0.2(A)以下と優れた特性が得られる(No.9)。Tiは1.0(mol%)でもＦＦ値が76、Idが1.0(A)以下の十分な特性が得られるが(No.10)、35.0(mol%)では電極材料が熔融してしまい、特性評価も不能な状態となった(No.19)。30.0(mol%)ではＦＦ値が78、Idが0.2(A)以下と極めて高い特性が得られた(No.24)。   Looking at the above evaluation results for individual constituent elements, high characteristics were obtained with an FF value of 77 and an Id of 0.2 (A) or less if Pb was included at 35.0 (mol%) (No. 9). In addition, 55.0 (mol%) obtained an extremely high characteristic with an FF value of 78 and Id of 0.2 (A) or less (No. 29), but 63.0 (mol%) had an insufficient FF value of 73. (No.33). If B is included in 1.0 (mol%), high characteristics with an FF value of 77 and an Id of 0.2 (A) or less can be obtained (No. 22), but without this, the FF value remains at 71 and insufficient. The result is (No. 20). In addition, 18.0 (mol%) provides sufficient characteristics with an FF value of 76 and Id of 0.5 (A) or less (No. 16), but 21.0 (mol%) has an insufficient FF value of 74. (No.18). If Si (8.0% mol%) is included, extremely high characteristics can be obtained with an FF value of 78 and Id of 0.2 (A) or less (No. 24), but 5.0 (mol%) melts the electrode material. As a result, the characteristic evaluation is impossible (No. 19). In addition, if 49.0 (mol%), the FF value is 76 and Id is 1.0 (A) or less, sufficient characteristics can be obtained (No. 10), but 51.2 (mol%) reduces the FF value to 36. It exceeded 1.0 (A) and the result was insufficient (No. 5). Li has a sufficient FF value of 76 and Id of 1.0 (A) or less even at 3.0 (mol%) (No. 10), but 35.0 (mol%) has an insufficient FF value of 73. (No.7). At 24.0 (mol%), excellent characteristics are obtained with an FF value of 77 and an Id of 0.2 (A) or less (No. 9). Ti has sufficient characteristics with an FF value of 76 and Id of 1.0 (A) or less even at 1.0 (mol%) (No. 10), but at 35.0 (mol%), the electrode material melts and the characteristics are evaluated. Became impossible (No. 19). At 30.0 (mol%), extremely high characteristics were obtained with an FF value of 78 and an Id of 0.2 (A) or less (No. 24).

上記の評価の範囲では、B量は1.0〜18.0(mol%)の範囲とすること、Si量は8.0〜49.0(mol%)の範囲とすること、Ti量は30.0(mol%)以下の範囲とすること、Pb量は63.0(mol%)未満とすること、Li量は35.0(mol%)未満とすることが、必須と言える。   In the above evaluation range, the B amount is in the range of 1.0 to 18.0 (mol%), the Si amount is in the range of 8.0 to 49.0 (mol%), and the Ti amount is in the range of 30.0 (mol%) or less. It is essential that the Pb content be less than 63.0 (mol%) and the Li content be less than 35.0 (mol%).

また、No.8、11、36、39、48は、Zn或いはPを含む６成分系(但し、No.39、48はLiを欠く)で、Pbが38.0〜64.0(mol%)、Bが3.0〜10.0(mol%)、Siが25.0〜31.3(mol%)、Alが0(mol%)、Liが0〜12.0(mol%)、Tiが1.0〜10.0(mol%)、Znが0〜15.0(mol%)、Zrが0(mol%)、Pが0〜1.0(mol%)の範囲内の組成では、Pbが38.0〜40.7(mol%)、Bが6.0〜8.0(mol%)、Siが29.0〜31.3(mol%)、Liが6.0〜12.0(mol%)、Tiが1.0〜8.0(mol%)、Pb(Si+Ti)が1.0〜1.3の範囲で、77〜78のＦＦ値および0.5(A)以下のIdが得られた。この評価結果において、Liを含まない組成ではＦＦ値が74以下に留まると共にIdが1.0(A)超となり(No.39、48)、特に、Pbが64.0(mol%)と過剰な組成になると、ＦＦ値が65に留まる。この評価の範囲ではLiは必須で、これを欠くと高いＦＦ値が得られない。また、Znは任意の元素であるが、15.0(mol%)含まれていても差し支えない(No.36)。   Nos. 8, 11, 36, 39, and 48 are 6-component systems containing Zn or P (however, Nos. 39 and 48 lack Li), Pb is 38.0 to 64.0 (mol%), and B is 3.0 to 10.0 (mol%), Si 25.0 to 31.3 (mol%), Al 0 (mol%), Li 0 to 12.0 (mol%), Ti 1.0 to 10.0 (mol%), Zn 0 to In the composition in the range of 15.0 (mol%), Zr 0 (mol%), P 0-1.0 (mol%), Pb 38.0-40.7 (mol%), B 6.0-8.0 (mol%), FF value of 77-78 in the range of Si 29.0-31.3 (mol%), Li 6.0-12.0 (mol%), Ti 1.0-8.0 (mol%), Pb (Si + Ti) 1.0-1.3 And Id below 0.5 (A) was obtained. In this evaluation result, in the composition containing no Li, the FF value stays below 74 and Id exceeds 1.0 (A) (No. 39, 48), and in particular, when Pb becomes an excessive composition of 64.0 (mol%). The FF value stays at 65. Li is indispensable in the range of this evaluation, and a high FF value cannot be obtained without it. Zn is an arbitrary element, but 15.0 (mol%) may be contained (No. 36).

また、No.6、31、44、49は、AlおよびPを含む７成分系で、Pbが27.0〜46.0(mol%)、Bが4.0〜10.6(mol%)、Siが24.0〜53.2(mol%)、Alが2.5〜6.0(mol%)、Liが3.7〜12.0(mol%)、Tiが1.0〜10.0(mol%)、ZnおよびZrが0(mol%)、Pが1.0〜6.0(mol%)の範囲内の組成では、Pbが38.0〜46.0(mol%)、Bが4.0〜6.0(mol%)、Siが24.0〜32.0(mol%)、Alが3.0〜6.0(mol%)、Liが12.0(mol%)、Tiが1.0〜10.0(mol%)、Pが1.0〜6.0(mol%)、Pb(Si+Ti)が0.9〜1.8の範囲で、76〜77のＦＦ値および0.5(A)以下のIdが得られた。この評価結果において、Siが53.2(mol%)と過剰な組成ではＦＦ値が44に留まった(No.49)。Siが過剰になると、ＦＦ値が著しく低下する。また、Pは任意の元素であるが、6.0(mol%)含まれていても差し支えない(No.31)。   Nos. 6, 31, 44, and 49 are 7-component systems containing Al and P. Pb is 27.0 to 46.0 (mol%), B is 4.0 to 10.6 (mol%), Si is 24.0 to 53.2 (mol) %), Al 2.5 to 6.0 (mol%), Li 3.7 to 12.0 (mol%), Ti 1.0 to 10.0 (mol%), Zn and Zr 0 (mol%), P 1.0 to 6.0 (mol) %) In the range of Pb 38.0-46.0 (mol%), B 4.0-6.0 (mol%), Si 24.0-32.0 (mol%), Al 3.0-6.0 (mol%), Li Is 12.0 (mol%), Ti is 1.0 to 10.0 (mol%), P is 1.0 to 6.0 (mol%), Pb (Si + Ti) is in the range of 0.9 to 1.8, FF value of 76 to 77 and 0.5 ( A) The following Id was obtained. In this evaluation result, the FF value stayed at 44 with an excessive composition of Si of 53.2 (mol%) (No. 49). When Si is excessive, the FF value is significantly reduced. P is an arbitrary element, but it may be contained in an amount of 6.0 (mol%) (No. 31).

また、No.1〜4、13、41〜43は、AlおよびZnを含む７成分系で、Pbが3.0〜37.3(mol%)、Bが3.0〜15.0(mol%)、Siが15.0〜29.7(mol%)、Alが1.0〜6.0(mol%)、Liが6.0〜30.0(mol%)、Tiが1.0〜15.0(mol%)、Znが6.0〜30.0(mol%)、ZrおよびPが0(mol%)の範囲内の組成では、Pbが6.0〜37.3(mol%)、Bが3.0〜15.0(mol%)、Siが15.0〜29.7(mol%)、Alが1.0〜6.0(mol%)、Liが6.0〜30.0(mol%)、Tiが1.0〜15.0(mol%)、Znが6.0〜30.0(mol%)、Pb(Si+Ti)が0.2〜1.3の範囲で、ＦＦ値77およびId 1.0(A)以下が得られた。この評価結果において、Pbが3.0(mol%)と過少でPb/(Si+Ti)が0.1と過小な組成ではＦＦ値が73に留まった(No.42)。なお、Znは任意の元素であるが、30.0(mol%)含まれていても差し支えない(No.43)。   Nos. 1 to 4, 13, and 41 to 43 are 7-component systems containing Al and Zn. Pb is 3.0 to 37.3 (mol%), B is 3.0 to 15.0 (mol%), Si is 15.0 to 29.7. (mol%), Al 1.0-6.0 (mol%), Li 6.0-30.0 (mol%), Ti 1.0-15.0 (mol%), Zn 6.0-30.0 (mol%), Zr and P 0 In the composition in the range of (mol%), Pb is 6.0-37.3 (mol%), B is 3.0-15.0 (mol%), Si is 15.0-29.7 (mol%), Al is 1.0-6.0 (mol%) , Li is 6.0 to 30.0 (mol%), Ti is 1.0 to 15.0 (mol%), Zn is 6.0 to 30.0 (mol%), Pb (Si + Ti) is in the range of 0.2 to 1.3, FF value 77 and Id 1.0 (A) or less was obtained. In this evaluation result, the FF value stayed at 73 (No. 42) when Pb was too small (3.0% by mol) and Pb / (Si + Ti) was too small (0.1). Zn is an arbitrary element, but 30.0 (mol%) may be contained (No. 43).

また、No.12、21、35、40は、Al、Zn、Pを含む８成分系で、Pbが39.0〜60.0(mol%)、Bが3.0〜8.0(mol%)、Siが22.0〜31.0(mol%)、Alが0.5〜3.0(mol%)、Liが1.0〜12.0(mol%)、Tiが1.0〜6.0(mol%)、Znが2.0〜7.0(mol%)、Zrが0(mol%)、Pが1.0〜2.0(mol%)の範囲内の組成では、Pbが39.0〜54.0(mol%)、Bが3.0〜8.0(mol%)、Siが30.1〜31.0(mol%)、Alが0.5〜3.0(mol%)、Liが1.0〜12.0(mol%)、Tiが3.0〜6.0(mol%)、Znが2.0〜5.0(mol%)、Pが1.0〜2.0(mol%)、Pb(Si+Ti)が1.1〜1.5の範囲で、ＦＦ値77〜78およびId 0.5(A)以下が得られた。この評価結果において、Pb/(Si+Ti)が2.6と過大な組成ではＦＦ値が73に留まった(No.35)。   Nos. 12, 21, 35 and 40 are 8-component systems containing Al, Zn and P. Pb is 39.0 to 60.0 (mol%), B is 3.0 to 8.0 (mol%), Si is 22.0 to 31.0 (mol%), Al 0.5-3.0 (mol%), Li 1.0-12.0 (mol%), Ti 1.0-6.0 (mol%), Zn 2.0-7.0 (mol%), Zr 0 (mol %), P is in the range of 1.0 to 2.0 (mol%), Pb is 39.0 to 54.0 (mol%), B is 3.0 to 8.0 (mol%), Si is 30.1 to 31.0 (mol%), Al Is 0.5 to 3.0 (mol%), Li is 1.0 to 12.0 (mol%), Ti is 3.0 to 6.0 (mol%), Zn is 2.0 to 5.0 (mol%), P is 1.0 to 2.0 (mol%), Pb When (Si + Ti) was in the range of 1.1 to 1.5, FF values of 77 to 78 and Id 0.5 (A) or less were obtained. In this evaluation result, the FF value stayed at 73 (No. 35) in the case of an excessive composition of Pb / (Si + Ti) of 2.6.

また、No.14、25、26、28、32、37、45は、Al、Zr、Pを含む８成分系で、Pbが38.6〜58.5(mol%)、Bが4.0〜7.9(mol%)、Siが25.5〜38.0(mol%)、Alが0.5〜12.0(mol%)、Liが1.0〜12.0(mol%)、Tiが0〜3.0(mol%)、Znが0(mol%)、Zrが0.5(mol%)、Pが2.0〜9.0(mol%)の範囲内の組成では、Pbが50.0〜58.5(mol%)、Bが4.0〜6.0(mol%)、Siが25.5〜32.0(mol%)、Alが0.5〜12.0(mol%)、Liが1.0〜6.0(mol%)、Tiが1.0〜3.0(mol%)、Zrが0.5(mol%)、Pが2.0(mol%)、Pb(Si+Ti)が1.4〜2.0の範囲で、ＦＦ値77〜78およびId 0.5(A)以下が得られた。この評価結果において、Tiを欠く組成ではＦＦ値が72〜74に留まり(No.25、28)、Pが9.0(mol%)と過剰な組成ではＦＦ値が68に留まった(No.14)。なお、Alは任意の元素であるが、12.0(mol%)含まれていても差し支えない(No.37)。   In addition, No.14, 25, 26, 28, 32, 37, 45 is an 8-component system containing Al, Zr, P, Pb 38.6-58.5 (mol%), B 4.0-7.9 (mol%) Si: 25.5-38.0 (mol%), Al: 0.5-12.0 (mol%), Li: 1.0-12.0 (mol%), Ti: 0-3.0 (mol%), Zn: 0 (mol%), Zr Is 0.5 (mol%), P is in the range of 2.0 to 9.0 (mol%), Pb is 50.0 to 58.5 (mol%), B is 4.0 to 6.0 (mol%), Si is 25.5 to 32.0 (mol) %), Al 0.5-12.0 (mol%), Li 1.0-6.0 (mol%), Ti 1.0-3.0 (mol%), Zr 0.5 (mol%), P 2.0 (mol%), Pb When (Si + Ti) was in the range of 1.4 to 2.0, FF values of 77 to 78 and Id 0.5 (A) or less were obtained. In this evaluation result, in the composition lacking Ti, the FF value stayed at 72 to 74 (No. 25, 28), and P was 9.0 (mol%) and the FF value stayed at 68 in the excessive composition (No. 14). . Al is an arbitrary element, but 12.0 (mol%) may be contained (No. 37).

また、No.17、27、34、38、46、47は、９成分系で、Pbが6.0〜62.0(mol%)、Bが3.0〜10.0(mol%)、Siが25.0〜38.0(mol%)、Alが0.5〜12.0(mol%)、Liが1.0〜12.0(mol%)、Tiが1.0〜4.0(mol%)、Znが1.0〜16.0(mol%)、Zrが0.5〜1.0(mol%)、Pが1.0〜2.0(mol%)の範囲内の組成では、Pbが43.0〜62.0(mol%)、Bが3.0〜8.0(mol%)、Siが25.0〜30.0(mol%)、Alが0.5〜1.0(mol%)、Liが1.0〜12.0(mol%)、Tiが1.0〜3.0(mol%)、Zrが0.5〜1.0(mol%)、Pが1.0〜2.0(mol%)、Pb(Si+Ti)が1.5〜2.4の範囲で、ＦＦ値76〜77およびId 1.0(A)以下が得られた。この評価結果において、Pb(Si+Ti)が0.1と過小な組成ではＦＦ値が43に留まった(No.46)。すなわち、個々の成分は好ましい範囲内にあっても、Pb(Si+Ti)が過小或いは過大では、高いＦＦ値が得られない。   No. 17, 27, 34, 38, 46 and 47 are 9 component systems, Pb is 6.0 to 62.0 (mol%), B is 3.0 to 10.0 (mol%), Si is 25.0 to 38.0 (mol%) ), Al 0.5-12.0 (mol%), Li 1.0-12.0 (mol%), Ti 1.0-4.0 (mol%), Zn 1.0-16.0 (mol%), Zr 0.5-1.0 (mol%) ), P is in the range of 1.0 to 2.0 (mol%), Pb is 43.0 to 62.0 (mol%), B is 3.0 to 8.0 (mol%), Si is 25.0 to 30.0 (mol%), Al is 0.5-1.0 (mol%), Li 1.0-12.0 (mol%), Ti 1.0-3.0 (mol%), Zr 0.5-1.0 (mol%), P 1.0-2.0 (mol%), Pb ( In the range of Si + Ti) from 1.5 to 2.4, FF values of 76 to 77 and Id 1.0 (A) or less were obtained. In this evaluation result, the FF value stayed at 43 in the case of an excessively small composition of Pb (Si + Ti) of 0.1 (No. 46). That is, even if each component is within a preferable range, a high FF value cannot be obtained if Pb (Si + Ti) is too small or too large.

また、以上の実施例の中では、No.8、11、12、21、23、24、29、32がＦＦ値が78と高いことから好ましく、No.12、21、24、29、32は、ＦＦ値が78と高く且つIdも0.2(A)以下と小さいので特に好ましい。これらの中でも、No.12、21は、ρcが0.012(Ω・cm2)と低く、最も好ましいと言える。 In the above examples, Nos. 8, 11, 12, 21, 23, 24, 29, and 32 are preferable because the FF value is as high as 78, and Nos. 12, 21, 24, 29, and 32 are The FF value is particularly high because it is as high as 78 and the Id is as small as 0.2 (A) or less. Among these, Nos. 12 and 21 are most preferable because ρc is as low as 0.012 (Ω · cm 2 ).

以上、本発明を図面を参照して詳細に説明したが、本発明は更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得るものである。   As mentioned above, although this invention was demonstrated in detail with reference to drawings, this invention can be implemented also in another aspect, A various change can be added in the range which does not deviate from the main point.

１０：太陽電池、１２：太陽電池モジュール、１４：封止材、１６：表面ガラス、１８：保護フィルム、２０：シリコン基板、２２：ｎ層、２４：ｐ+層、２６：反射防止膜、２８：受光面電極、３０：裏面電極、３２：受光面、３４：全面電極、３６：帯状電極、３８：半田リボン 10: solar cell, 12: solar cell module, 14: sealing material, 16: surface glass, 18: protective film, 20: silicon substrate, 22: n layer, 24: p + layer, 26: antireflection film, 28 : Light receiving surface electrode, 30: Back electrode, 32: Light receiving surface, 34: Full surface electrode, 36: Strip electrode, 38: Solder ribbon

Claims (3)

導電性粉末と、ガラスフリットと、ベヒクルとを含む太陽電池電極用ペースト組成物であって、
前記ガラスフリットが酸化物換算で6〜62(mol%)のPbOと、1〜18(mol%)のB2O3と、8〜49(mol%)のSiO2と、1〜30(mol%)のLi2Oと、1〜30(mol%)のTiO2と、0〜6(mol%)のP2O5とを含み、且つPb/(Si＋Ti)(mol比)が0.2〜2.4の範囲内にあるガラスから成ることを特徴とする太陽電池電極用ペースト組成物。 A solar cell electrode paste composition comprising a conductive powder, a glass frit, and a vehicle,
Wherein the PbO glass frit in terms of oxide 6~62 (mol%), and B 2 O 3 of 1~18 (mol%), and SiO 2 of 8~49 (mol%), 1~30 ( mol %) Li 2 O, 1 to 30 (mol%) TiO 2 , and 0 to 6 (mol%) P 2 O 5 , and Pb / (Si + Ti) (mol ratio) is 0.2 to 2.4. A paste composition for a solar cell electrode, comprising a glass within the range of. 前記ガラスは酸化物換算で6〜60(mol%)のPbOと、3〜12(mol%)のB2O3と、8〜32(mol%)のSiO2と、1〜30(mol%)のLi2Oと、1〜30(mol%)のTiO2と、0〜4(mol%)のP2O5とを含み、且つPb/(Si＋Ti)(mol比)が0.2〜2.0の範囲内にある請求項１の太陽電池電極用ペースト組成物。 The glass and PbO of 6 to 60 (mol%) in terms of oxide, and B 2 O 3 of 3 to 12 (mol%), and SiO 2 of 8~32 (mol%), 1~30 ( mol% ) Li 2 O, 1 to 30 (mol%) TiO 2 , and 0 to 4 (mol%) P 2 O 5 , and Pb / (Si + Ti) (mol ratio) is 0.2 to 2.0 The paste composition for solar cell electrodes of Claim 1 which exists in the range. 前記ガラスは酸化物換算で38〜59(mol%)のPbOと、3〜8(mol%)のB2O3と、8〜32(mol%)のSiO2と、1〜12(mol%)のLi2Oと、3〜30(mol%)のTiO2と、0〜2(mol%)のP2O5とを含み、且つPb/(Si＋Ti)(mol比)が1.0〜1.9の範囲内にある請求項１の太陽電池電極用ペースト組成物。 The glass and PbO of 38 to 59 in terms of oxides (mol%), and B 2 O 3 of 3~8 (mol%), and SiO 2 of 8~32 (mol%), 1~12 ( mol% ) Li 2 O, 3 to 30 (mol%) TiO 2 , and 0 to 2 (mol%) P 2 O 5 , and Pb / (Si + Ti) (mol ratio) is 1.0 to 1.9 The paste composition for solar cell electrodes of Claim 1 which exists in the range.
JP2011267345A 2011-12-06 2011-12-06 Paste composition for solar cell electrode Pending JP2013120807A (en)

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