JP2004319309A - Semiconductor for photoelectric conversion material, photoelectric conversion element, and solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor for a photoelectric conversion material having high photoelectric conversion efficiency and high stability, a photoelectric conversion element, and a solar cell. <P>SOLUTION: The semiconductor for the photoelectric conversion material contains a coloring matter represented by general formula 1. In the formula, Z and Z' independently represent an atomic group necessary for forming a five- or six-membered ring together with a carbon atom, each ring has at least one carboxyl or constituent group having the carboxyl, at least one of rings has the carboxyl or the substituent group having the carboxyl, B<SB>1</SB>and B<SB>2</SB>independently represent -C(R<SB>1</SB>)R<SB>2</SB>- or -NR<SB>3</SB>-, and R<SB>1</SB>-R<SB>3</SB>represent a hydrogen atom or the substituent group. The semiconductor for the photoelectric conversion material having high photoelectric conversion efficiency and high stability is realized and the photoelectric conversion element and the solar cell are also realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４５】
【化６】

【００４６】
以下に、上記一般式（Ｃｐ−１）〜（Ｃｐ−２６）で表される化合物について詳しく説明する。
【００４７】
《一般式（Ｃｐ−１）》
一般式（Ｃｐ−１）において、Ｒ_６１は、アルキル基、アリール基、複素環基、アシルアミノ基、アミノ基、カルボキシル基、アルコキシル基、アリールオキシ基、アルキルチオ基、アリールチオ基、ウレイド基またはアルコキシカルボニルアミノ基を表す。Ｒ_６２はアルキル基、アリール基または複素環基を表す。
【００４８】
ここで、前記Ｒ_６１、Ｒ_６２で各々表される基は、上記置換基の説明における基と同義である。
【００４９】
式中、Ｒ_６１で表される基としては、好ましくは、アルキル基、アリール基、アシルアミノ基、アミノ基、ウレイド基、アルコキシカルボニルアミノ基、カルボキシル基等が挙げられ、更に好ましくは、アリール基、アシルアミノ基、アニリノ基、カルボキシル基である。
【００５０】
式中、Ｒ_６２で表される基としては、好ましくは、アリール基、複素環基が挙げられるが、更に好ましくはアリール基である。
【００５１】
《一般式（Ｃｐ−２）、一般式（Ｃｐ−３）》
一般式（Ｃｐ−２）、（Ｃｐ−３）において、Ｒ_６３、Ｒ_６４は各々、水素原子、アルキル基、アルケニル基、アリール基、複素環基、アシルアミノ基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、アミノ基、アルキルアミノ基、アルキルチオ基、アリールチオ基、アルコキシル基、アリールオキシ基、ウレイド基、アルコキシカルボニルアミノ基、カルバモイル基、カルボキシル基またはアルコキシカルボニル基を表す。
【００５２】
ここで、前記Ｒ_６３、Ｒ_６４で各々表される基は、上記置換基の説明における基と同義である。
【００５３】
式中、Ｒ_６３で表される基としては、好ましくは、アルキル基、アリール基、カルボキシル基、アルコキシル基、カルバモイル基が挙げられるが、更に好ましくは、メチル基、ｔｅｒｔ−ブチル基、カルボキシル基である。
【００５４】
式中、Ｒ_６４で表される基としては、好ましくは、アルキル基、アルケニル基、アリール基である。
【００５５】
《一般式（Ｃｐ−４）、一般式（Ｃｐ−５）》
一般式（Ｃｐ−４）、（Ｃｐ−５）において、Ｒ_６３およびＲ_６５は、前記一般式（Ｃｐ−２）、（Ｃｐ−３）に記載のＲ_６３およびＲ_６４と同義である。
【００５６】
Ｒ_６６およびＲ_６７は、各々、水素原子、アルキル基、アリール基、複素環基、アシルアミノ基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、アミノ基、アルキルチオ基、アリールチオ基、アルコキシル基、アリールオキシ基、ウレイド基、アルコキシカルボニルアミノ基、アシル基、カルボキシル基、アルコキシカルボニル基またはカルバモイル基を表す。
【００５７】
ここで、前記Ｒ_６５、Ｒ_６６およびＲ_６７で各々表される基は、上記置換基の説明における基と同義である。
【００５８】
式中、Ｒ_６５で表される基としては、好ましくは、アルキル基、アリール基、アルコキシル基、アリールオキシ基等が挙げられ、Ｒ_６３、Ｒ_６６、Ｒ_６７で、各々表される基としては、好ましくは、水素原子、アルキル基、アリール基、カルボキシル基、アルコキシカルボニル基、カルバモイル基が挙げられる。
【００５９】
《一般式（Ｃｐ−６）》
一般式（Ｃｐ−６）において、Ｒ_６８およびＲ_６９は各々、水素原子、アルキル基、アリール基、複素環基、アシルアミノ基、アルキルスルホニル基、アリールスルホニルアミノ基、アミノ基、アルキルチオ基、アリールチオ基、アルコキシル基、アリールオキシ基、ウレイド基、アルコキシカルボニルアミノ基、カルボキシル基、アシル基、アルコキシカルボニル基またはカルバモイル基を表す。
【００６０】
ここで、前記Ｒ_６８、Ｒ_６９で各々表される基は、上記置換基の説明における基と同義である。
【００６１】
式中、Ｒ_６８、Ｒ_６９で表される基としては、好ましくは、各々水素原子、アルキル基、アリール基、カルボキシル基等が挙げられる。
【００６２】
《一般式（Ｃｐ−７）、（Ｃｐ−８）、（Ｃｐ−９）、（Ｃｐ−１０）》
一般式（Ｃｐ−７）、（Ｃｐ−８）、（Ｃｐ−９）、（Ｃｐ−１０）において、Ｒ_７０、Ｒ_７１は、ハロゲン原子、アルキル基、アリール基、複素環基、シリル基、アシルアミノ基、アルキルスルホニル基アミノ基、アリールスルホニルアミノ基、アミノ基、ウレイド基、アルキルチオ基、アリールチオ基、アルコキシル基、カルボキシル基またはアルコキシカルボニルアミノ基を表し、Ｒ_７２およびＲ_７３は各々、水素原子またはアルキル基を表し、ａは０ないし３のいずれかの整数を表し、ｂは０ないし２のいずれかの整数を表し、ｃは０ないし４のいずれかの整数を表す。ａ、ｂ、またはｃが複数のとき複数個のＲ_７０は同一であっても、異なっていてもよい。
【００６３】
ここで、前記Ｒ_７０、Ｒ_７１、Ｒ_７２、Ｒ_７３で各々表される基は、上記置換基の説明における基と同義である。
【００６４】
式中、Ｒ_７０で表される基としては、好ましくは、ハロゲン原子、アルキル基、アリール基、カルボキシル基であり、Ｒ_７１で表される基としては、好ましくは、ハロゲン原子、アルキル基、アシルアミノ基、カルバモイル基、カルボキシル基等が挙げられ、Ｒ_７２、Ｒ_７３で各々表される基としては、水素原子、メチル基、エチル基等が挙げられる。また、好ましくは、ａは１または２を表し、ｂは１または２を表し、ｃは０ないし２の整数を表す。
【００６５】
《一般式（Ｃｐ−１１）》
一般式（Ｃｐ−１１）において、Ｒ_７４はカルバモイル基、アルコキシカルボニル基、カルボキシル基、シアノ基、スルファモイル基、アシルアミノ基、ウレイド基、アルコキシカルボニルアミノ基またはアルキルもしくはアリールスルホニルアミノ基を表し、Ｒ_７５はハロゲン原子、アルキル基、アリール基、複素環基、アシルアミノ基、アルキルもしくはアリールスルホニルアミノ基、アミノ基、アルキルチオ基、アリールチオ基、アルコキシル基、アリールオキシ基、カルボキシル基、ウレイド基またはアルコキシカルボニルアミノ基を表し、ｄは０ないし４のいずれかの整数を表す。ｄが複数のとき、複数個のＲ_７５は同一であっても異なっていてもよい。
【００６６】
ここで、前記Ｒ_７４、Ｒ_７５で各々表される基は、上記置換基の説明における基と同義である。
【００６７】
式中、Ｒ_７４で表される基としては、好ましくは、カルバモイル基、スルファモイル基、アシルアミノ基、カルボキシル基であり、Ｒ_７５で表される基としては、好ましくは、アシルアミノ基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、ウレイド基、アルコキシカルボニルアミノ基であり、ｄは０または１である。
【００６８】
《一般式（Ｃｐ−１２）》
一般式（Ｃｐ−１２）において、Ｒ_８２、Ｒ_８３、Ｒ_８４は各々、水素原子、アルキル基、アリール基、複素環基、アシルアミノ基、アルキルもしくはアリールスルホニルアミノ基、アミノ基、アルキルチオ基、アリールチオ基、アルコキシ基、アリールオキシ基、ウレイド基、アルコキシカルボニルアミノ基、アシル基、カルボキシル基、アルコキシカルボニル基またはカルバモイル基を表す。
【００６９】
ここで、Ｒ_８２、Ｒ_８３、Ｒ_８４で各々表される基は、上記置換基の説明における基と同義である。
【００７０】
Ｒ_８２、Ｒ_８３、Ｒ_８４で各々表される基としては、好ましくは、水素原子、アルキル基、アリール基、複素環基、カルボキシル基、アルコキシ基等が挙げられる。
【００７１】
《一般式（Ｃｐ−１３）》
一般式（Ｃｐ−１３）において、Ｒ_８５、Ｒ_８６は、各々、水素原子、アルキル基、アリール基、複素環基、アシルアミノ基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、アミノ基、アルキルチオ基、アリールチオ基、アルコキシル基、アリールオキシ基、ウレイド基、アルコキシカルボニルアミノ基、アシル基、カルボキシル基、アルコキシカルボニル基またはカルバモイル基を表す。
【００７２】
ここで、Ｒ_８５、Ｒ_８６で各々表される基は、上記置換基の説明における基と同義である。
【００７３】
式中、Ｒ_８５、Ｒ_８６で各々表される基としては、好ましくは、水素原子、アルキル基、アリール基、複素環基、アシルアミノ基、アルキルスルホニルアミノ基、アリールスルホニルアミノ基、カルボキシル基等が挙げられる。
【００７４】
《一般式（Ｃｐ−１４）、（Ｃｐ−１５）、（Ｃｐ−１６）、（Ｃｐ−１７）、（Ｃｐ−１８）》
一般式（Ｃｐ−１４）〜（Ｃｐ−１８）において、Ｒ_８７、Ｒ_８８は、各々水素原子、アルキル基、アリール基、複素環基、カルバモイル基、アルコキシカルボニル基、アリールオキシカルボニル基、カルボキシル基、シアノ基、スルファモイル基、アルキルスルホニル基、アリールスルホニル基またはニトロ基を表し、Ｒ_８９、Ｒ_９０は各々水素原子、アルキル基、アリール基または複素環基を表す。
【００７５】
ここで、Ｒ_８７、Ｒ_８８、Ｒ_８９、Ｒ_９０で、各々表される基は、上記置換基の説明における基と同義である。
【００７６】
式中、Ｒ_８７で表される基としては、好ましくは、カルバモイル基、アルコキシカルボニル基、カルボキシル基、シアノ基等がであり、更に好ましくは、カルボキシル基、シアノ基である。Ｒ_８８で表される基としては、カルバモイル基、カルボキシル基、アルコキシカルボニル基、シアノ基、アルキルスルホニル基、アリールスルホニル基等であり、更に好ましくは、アルコキシカルボニル基、カルボキシル基等である。Ｒ_８９、Ｒ_９０で、各々表される基としては、好ましくは、アルキル基、アリール基等であり、更に好ましくは、アリール基である。
【００７７】
《一般式（Ｃｐ−１９）〜（Ｃｐ−２６）》
一般式（Ｃｐ−１９）〜（Ｃｐ−２６）において、Ｒ_９１、Ｒ_９２は、各々アルキル基、アリール基、複素環基、カルバモイル基、アルコキシカルボニル基、アリールオキシカルボニル基、カルボキシル基、シアノ基、スルファモイル基、アルキルスルホニル基、アリールスルホニル基またはニトロ基を表し、Ｒ_９３、Ｒ_９４、Ｒ_９５は、各々水素原子、アルキル基、アリール基、複素環基、アシルアミノ基、ウレイド基、アルコキシカルボニルアミノ基、アルキルもしくはアリールスルホニルアミノ基、ハロゲン原子、カルボキシル基、アミノ基、アルキルチオ基、アリールチオ基、アルコキシル基またはアリールオキシ基を表す。
【００７８】
ここで、Ｒ_９１、Ｒ_９２、Ｒ_９３、Ｒ_９４、Ｒ_９５で各々表される基は、上記置換基の説明における基と同義である。
【００７９】
式中、Ｒ_９１で表される基としては、好ましくは、アリール基、複素環基、カルバモイル基、アルコキシカルボニル基、カルボキシル基、シアノ基等であり、Ｒ_９２で表される基としては、好ましくは、カルバモイル基、アルコキシカルボニル基、カルボキシル基、シアノ基、スルファモイル基ま、アルキルスルホニル基、アリールスルホニル基等であり、Ｒ_９３、Ｒ_９４、Ｒ_９５で各々表される基としては、好ましくは、水素原子、アルキル基、アシルアミノ基、ハロゲン原子、カルボキシル基、アミノ基、アルキルチオ基、アリールチオ基等が挙げられる。
【００８０】
本発明に係る環構造部位Ｑ、Ｑ′としては、上記一般式（Ｃｐ−１）〜（Ｃｐ−２６）で表される基の中でも、立体障害性の少ない５員環を形成する一般式（Ｃｐ−１）〜（Ｃｐ−６）、（Ｃｐ−１３）〜（Ｃｐ−２６）が好ましい。
【００８１】
また、環構造部位Ｑ、Ｑ′は好ましくは前記一般式ａ〜ｄで表される事が好ましい。
【００８２】
一般式ａ〜ｄにおいて、Ｒ_４及びＲ_５は水素原子又は置換基を表し、Ｚ_２は５又は６員環を形成するために必要な原子団を表わし、置換基を有していてもよく、置換基で結合し縮環を形成してもよく、＊でＱ或いはＱ′以外の部分と結合する。また、それぞれの環構造は少なくとも１つはカルボキシル基またはカルボキシル基を有する置換基を有している。Ｒ_４及びＲ_５で表される置換基は前述した置換基と同義である。
【００８３】
Ｚ_２を更に具体的に説明すると例えば、一般式ａの場合は一般式ａ−１〜ａ−９等で表される化合物が挙げられる。
【００８４】
【化７】

【００８５】
一般式ａ−１〜ａ−３、ａ−６〜ａ−９は前述した一般式（Ｃｐ−２）〜（Ｃｐ−４）、（Ｃｐ−２３）〜（Ｃｐ−２６）と同一であり、一般式ａ−１〜ａ−３における、Ｒ_４は前記一般式（Ｃｐ−２）〜（Ｃｐ−４）におけるＲ_６３と、また一般式ａ−１、ａ−２におけるＲ_６は前記一般式（Ｃｐ−２）〜（Ｃｐ−３）におけるＲ_６４と、一般式ａ−３におけるＲ_６は前記Ｒ_６５と、Ｒ_７はまた前記Ｒ_６６と同義である。
【００８６】
また、一般式ａ−４及びａ−５におけるＲ_４、Ｒ_６、Ｒ_７についても前記Ｒ_６４と同義である。
【００８７】
一般式ａ−６〜ａ−９におけるＲ_４は前記一般式（Ｃｐ−２３）〜（Ｃｐ−２６）におけるＲ_９１と同義であり、一般式ａ−６およびａ−８におけるＲ_６は前記一般式（Ｃｐ−２３）〜（Ｃｐ−２６）におけるＲ_９３と同義であり、一般式ａ−６におけるＲ_７は前記一般式（Ｃｐ−２３）〜（Ｃｐ−２６）におけるＲ_９４と同義であり、一般式ａ−７およびａ−９におけるＲ_７は前記一般式（Ｃｐ−２３）〜（Ｃｐ−２６）におけるＲ_９５と同義である。
【００８８】
これらのうち、一般式ａ−１、ａ−２、ａ−３、ａ−６及びａ−７の構造が好ましく、更に好ましくは一般式ａ−１、ａ−３及びａ−６である。
【００８９】
一般式ｂ〜ｄにおいても同様の構造をもつ好ましい環構造が挙げられる。例えば一般式ｂについては一般式（Ｃｐ−１６）、（Ｃｐ−１８）、（Ｃｐ−２０）及び（Ｃｐ−２２）が、一般式ｃについては一般式（Ｃｐ−１４）、（Ｃｐ−１５）、（Ｃｐ−１７）、（Ｃｐ−１９）及び（Ｃｐ−２１）が、一般式ｄについては一般式（Ｃｐ−５）〜（Ｃｐ−６）などが挙げられるがこれらに限定される事はない。
【００９０】
また、本発明に係る、前記一般式（１）または（２）で各々表される化合物において、環構造Ｑ、Ｑ′としては５員環である（Ｃｐ−１）〜（Ｃｐ−６）、（Ｃｐ−１３）〜（Ｃｐ−２６）が好ましく、特に好ましく用いられるのは、前記一般式（Ｃｐ−１）を有するピラゾロン化合物、前記一般式（Ｃｐ−２）または（Ｃｐ−３）を有するピラゾロアゾール化合物や、前記一般式（Ｃｐ−５）、（Ｃｐ−１３）を有するイミダゾール系化合物前記一般式（Ｃｐ−１４）、（Ｃｐ−１５）を有するピロロトリアゾール化合物が好ましい。
【００９１】
以下に、本発明に係る前記一般式（１）または（２）で表される化合物の具体例を示すが、本発明は、これらに限定されない。
【００９２】
まず以下にＱ又はＱ′で表される構造の具体例を示すがこれらに限定されない。
【００９３】
【化８】

【００９４】
【化９】

【００９５】
【化１０】

【００９６】
【化１１】

【００９７】
【化１２】

【００９８】
【化１３】

【００９９】
【化１４】

【０１００】
【化１５】

【０１０１】
次に色素構造の具体例を示すがこれらに限定される事はない。
【０１０２】
【化１６】

【０１０３】
【化１７】

【０１０４】
本発明に係る前記一般式（１）または（２）で表される色素（化合物）は、例えば、特開平１０−２０４３１０号、特開２０００−２６５０７７号公報、特開２０００−３４５０５９号公報、特開２００２−８０７６４号公報等に記載された従来公知の方法を参考にして合成することができる。
【０１０５】
以下に具体的に合成法の一例を示すが、その他の色素（化合物）も同様にして合成することが可能であり、合成法としては、これらに限定されない。
【０１０６】
合成例１
（例示化合物Ｉ−６の合成）
（１）合成ルート
【０１０７】
【化１８】

【０１０８】
（２）例示化合物Ｉ−６の合成
中間体２を０．３７ｇ、ｎ−ブタノール１２ｍｌ中で加熱還流させ完溶した後に、中間体１を１．５０ｇ、ｎ−ブタノール１０ｍｌに溶解した溶液を添加して５時間還流反応させる。反応終了後冷却し、そのまま再結晶して、例示化合物Ｉ−６を０．９２ｇ得た。ＭＡＳＳ、Ｈ−ＮＭＲ、ＩＲスペクトルによって同定し、目的物であることを確認した。この化合物のメタノール中での吸収極大は５５０ｎｍであった。
【０１０９】
合成例２
（例示化合物ＩＩ−１０の合成）
（１）合成ルート
【０１１０】
【化１９】

【０１１１】
（２）例示化合物ＩＩ−１０の合成
中間体３を４．００ｇ及び中間体４を１．４０ｇ、ｎ−ブタノール１５ｍｌ、トルエン１５ｍｌ中に加え、１時間還流反応させる。反応終了後冷却し、アセトニトリルを加え再結晶し、例示化合物ＩＩ−１０を２．１１ｇ得た。ＭＡＳＳ、Ｈ−ＮＭＲ、ＩＲスペクトルによって同定し、目的物であることを確認した。この化合物のメタノール中での吸収極大は６６０ｎｍであった。
【０１１２】
《光電変換材料用半導体の増感処理》
本発明の光電変換材料用半導体は、前記一般式（１）または（２）で表されるいずれか１種の色素を含むことにより増感し、本発明に記載の効果を奏することが可能となる。ここで、該色素を含むとは、半導体表面への吸着、半導体が多孔質などのポーラスな構造を有する場合には、半導体の多孔質構造に前記化合物が入りこむ等の種々の態様をさす。
【０１１３】
また、半導体層（半導体でもよい）１ｍ^２あたりの前記一般式（１）または（２）で表される、各々の色素の総含有量は０．０１ミリモル〜１００ミリモルの範囲が好ましく、更に好ましくは、０．１ミリモル〜５０ミリモルであり、特に好ましくは、０．５ミリモル〜２０ミリモルである。
【０１１４】
本発明に係る前記一般式（１）または（２）で表されるいずれか１種の色素を用いて増感処理を行う場合、前記色素を単独で用いてもよいし、複数を併用することも、本発明に係る前記一般式（１）または（２）で表されるいずれか１種の色素と他の化合物（例えば米国特許第４，６８４，５３７号明細書、同第４，９２７，７２１号明細書、同第５，０８４，３６５号明細書、同第５，３５０，６４４号明細書、同第５，４６３，０５７号明細書、同第５，５２５，４４０号明細書等の各明細書、特開平７−２４９７９０号公報、特開２０００−１５０００７号公報等に記載の化合物）とを混合して用いることもできる。
【０１１５】
特に、本発明の光電変換材料用半導体の用途が、後述する太陽電池である場合には、光電変換の波長域をできるだけ広くして太陽光を有効に利用できるように、吸収波長の異なる二種類以上の色素を混合して用いることが好ましい。
【０１１６】
半導体に、前記一般式（１）または（２）で表されるいずれか１種の色素を含ませるには、前記化合物を適切な溶媒（エタノールなど）に溶解し、その溶液中によく乾燥した半導体を長時間浸漬する方法が一般的である。
【０１１７】
前記一般式（１）または（２）で表されるいずれか１種の色素を複数種類併用したり、その他の増感色素化合物とを併用した光電変換材料用半導体を作製する際には、各々の化合物の混合溶液を調製して用いてもよいし、それぞれの化合物について溶液を用意して、各溶液に順に浸漬して作製することもできる。各化合物について別々の溶液を用意し、各溶液に順に浸漬して作製する場合は、半導体に前記化合物や増感色素等を含ませる順序がどのようであっても本発明に記載の効果を得ることができる。また、前記色素または化合物を単独で吸着させた半導体微粒子を混合する等することにより光電変換材料用半導体を作製してもよい。
【０１１８】
吸着処理は半導体が粒子状の時に行ってもよいし、支持体上に膜を形成した後に行ってもよい。吸着処理に用いる色素または化合物を溶解した溶液は、それを常温で用いてもよいし、該化合物が分解せず溶液が沸騰しない温度範囲で加熱して用いてもよい。また、後述する光電変換素子の製造のように、半導体微粒子の塗布後（感光層の形成後）に、前記化合物の吸着を実施してもよい。また、半導体微粒子と本発明の前記色素とを同時に塗布することにより、前記色素の吸着を実施してもよい。また、未吸着の色素は洗浄によって除去することが出来る。
【０１１９】
また、本発明の光電変換材料用半導体の増感処理については、半導体を、前記一般式（１）または（２）で表されるいずれか１種の色素を含むことにより増感処理が行われるが、増感処理の詳細については、後述する光電変換素子のところで具体的に説明する。
【０１２０】
また、空隙率の高い半導体薄膜を有する光電変換材料用半導体の場合には、空隙に水分、水蒸気などにより水が半導体薄膜上、並びに半導体薄膜内部の空隙に吸着する前に、前記色素または化合物や増感色素等の吸着処理（光電変換材料用半導体の増感処理）を完了することが好ましい。
【０１２１】
本発明の光電変換材料用半導体は、有機塩基を用いて表面処理してもよい。前記有機塩基としては、ジアリールアミン、トリアリールアミン、ピリジン、４−ｔ−ブチルピリジン、ポリビニルピリジン、キノリン、ピペリジン、アミジン等が挙げられるが、中でも、ピリジン、４−ｔ−ブチルピリジン、ポリビニルピリジンが好ましい。
【０１２２】
上記の有機塩基が液体の場合はそのまま、固体の場合は有機溶媒に溶解した溶液を準備し、本発明の光電変換材料用半導体を液体アミンまたはアミン溶液に浸漬することで、表面処理を実施できる。
【０１２３】
また、本発明に係る前記一般式（１）または（２）で表されるいずれか１種の色素と併用して用いることの出来る色素としては、本発明に係る半導体を分光増感しうるものならばいずれの色素も用いることができる。光電変換の波長域をできるだけ広くし、かつ変換効率を上げるため、二種類以上の色素を混合することが好ましい。また、目的とする光源の波長域と強度分布に合わせるように、混合する色素とその割合を選ぶことができる。
【０１２４】
本発明において併用して用いることの出来る色素としては、光電子移動反応活性、光耐久性、光化学的安定性等の総合的な観点から、金属錯体色素、フタロシアニン系色素、ポルフィリン系色素、ポリメチン系色素が好ましく用いられる。
【０１２５】
金属錯体色素の中では、特開２００１−２２３０３７号、同２００１−２２６６０７号、米国特許第４，９２７，７２１号、同第４，６８４，５３７号、同第５，０８４，３６５号、同第５，３５０，６４４号、同第５，４６３，０５７号、同第５，５２５，４４０号、特開平７−２４９７５０号、特表平１０−５０４５１２号、世界特許９８／０５０３９３号等に記載のルテニウム錯体色素が好ましく用いられる。
【０１２６】
ポルフィリン系色素、フタロシアニン系色素としては、特開２００１−２２３０３７に記載の色素が好ましい色素としてあげられる。
【０１２７】
ポリメチン系色素としては、従来公知のメチン系色素、特開平１１−３５８３６号公報、同１１−１５８３９５号公報、同１１−１６３３７８号公報、同１１−２１４７３０号公報、同１１−２１４７３１号公報、同１０−９３１１８号公報、同１１−２７３７５４号公報、特開２０００−１０６２２４号公報、同２０００−３５７８０９号公報、同２００１−５２７６６号公報、欧州特許第８９２，４１１号、同９１１，８４１号等に記載のものが挙げられる。
【０１２８】
《光電変換材料用半導体の作製方法》
本発明の光電変換材料用半導体の作製方法について説明する。
【０１２９】
本発明の光電変換材料用半導体の一態様としては、導電性支持体上に上記の光電変換材料用半導体を焼成により形成する等の方法が挙げられる。
【０１３０】
本発明の光電変換材料用半導体が焼成により作製される場合には、上記の色素や増感色素を用いての該半導体の増感（吸着、多孔質への入り込み等）処理は、焼成後に実施することが好ましい。焼成後、半導体に水が吸着する前に、素早く化合物の吸着処理を実施することが特に好ましい。
【０１３１】
本発明の光電変換材料用半導体が粒子状の場合には、光電変換材料用半導体を導電性支持体に塗布あるいは吹き付けて、半導体電極を作製するのがよい。また、本発明の光電変換材料用半導体が膜状であって、導電性支持体上に保持されていない場合には、光電変換材料用半導体を導電性支持体上に貼合して半導体電極を作製することが好ましい。
【０１３２】
以下、本発明の光電変換材料用半導体の作製工程を具体的に述べる。
《半導体微粉末含有塗布液の調製》
まず、半導体の微粉末を含む塗布液を調製する。この半導体微粉末は、その１次粒子径が微細な程好ましく、その１次粒子径は、１ｎｍ〜５０００ｎｍが好ましく、更に好ましくは２ｎｍ〜５０ｎｍである。半導体微粉末を含む塗布液は、半導体微粉末を溶媒中に分散させることによって調製することができる。溶媒中に分散された半導体微粉末は、その１次粒子状で分散する。溶媒としては、半導体微粉末を分散し得るものであればよく、特に制約されない。
【０１３３】
前記溶媒としては、水、有機溶媒、水と有機溶媒との混合液が包含される。有機溶媒としては、メタノールやエタノール等のアルコール、メチルエチルケトン、アセトン、アセチルアセトン等のケトン、ヘキサン、シクロヘキサン等の炭化水素等が用いられる。塗布液中には、必要に応じ、界面活性剤や粘度調節剤（ポリエチレングリコール等の多価アルコール等）を加えることができる。溶媒中の半導体微粉末濃度の範囲は、０．１質量％〜７０質量％が好ましく、更に好ましくは０．１質量％〜３０質量％である。
【０１３４】
《半導体微粉末含有塗布液の塗布と形成された半導体層の焼成処理》
上記のようにして得られた半導体微粉末含有塗布液を導電性支持体上に塗布または吹きつけ、乾燥等を行った後、空気中または不活性ガス中で焼成して、導電性支持体上に半導体層（半導体膜）が形成される。
【０１３５】
導電性支持体上に塗布液を塗布、乾燥して得られる皮膜は、半導体微粒子の集合体からなるもので、その微粒子の粒径は使用した半導体微粉末の１次粒子径に対応するものである。
【０１３６】
このようにして導電性支持体等の基板上に形成された半導体微粒子集合体膜は、導電性支持体との結合力や、微粒子相互の結合力が弱く、機械的強度の弱いものであることから、前記半導体微粒子集合体膜を焼成処理して機械的強度を高め、基板に強く固着した焼成物膜となるため好ましく行われる。
【０１３７】
本発明においては、この焼成物膜はどのような構造を有していても良いが、多孔質構造膜（空隙を有する、ポーラスな層ともいう）であることが好ましい。
【０１３８】
ここで、本発明に係る半導体薄膜の空隙率は、１０体積％以下が好ましく、更に好ましくは、８体積％以下であり、特に好ましくは、０．０１体積％〜５体積％以下である。尚、半導体薄膜の空隙率は、誘電体の厚み方向に貫通性のある空隙率を意味し、水銀ポロシメーター（島津ポアライザー９２２０型）等の市販の装置を用いて測定することが出来る。
【０１３９】
多孔質構造を有する焼成物膜になった、半導体層の膜厚は、少なくとも１０ｎｍ以上が好ましく、更に好ましくは１００ｎｍ〜１００００ｎｍである。
【０１４０】
焼成処理時、焼成物膜の実表面積を適切に調整し、上記の空隙率を有する焼成物膜を得る観点から、焼成温度は１０００℃より低いことが好ましく、更に好ましくは、２００℃〜８００℃の範囲であり、特に好ましくは３００℃〜８００℃の範囲である。
【０１４１】
また、見かけ表面積に対する実表面積の比は、半導体微粒子の粒径及び比表面積や、焼成温度等によりコントロールすることができる。また、加熱処理後、半導体粒子の表面積を増大させたり、半導体粒子近傍の純度を高め、色素から半導体粒子への電子注入効率を高める目的で、例えば四塩化チタン水溶液を用いた化学メッキや三塩化チタン水溶液を用いた電気化学的メッキ処理を行ってもよい。
【０１４２】
《半導体の増感処理》
半導体の増感処理は、前記のように、色素を適切な溶媒に溶解し、その溶液に前記半導体の焼成物膜を形成した基板を浸漬することによって行われる。その際には半導体層（半導体膜ともいう）を焼成物膜を形成させた基板を、あらかじめ減圧処理したり加熱処理したりして膜中の気泡を除去し、前記一般式（１）または（２）のいずれか１種の色素が半導体層（半導体膜）内部深くに進入できるようにしておくことが好ましく、半導体層（半導体膜）が多孔質構造膜である場合には特に好ましい。
【０１４３】
《溶媒》
前記一般式（１）または（２）のいずれか１種の色素を溶解するのに用いる溶媒は、前記色素を溶解することができ、且つ、半導体を溶解したり半導体と反応したりすることのないものであれば格別の制限はないが、溶媒に溶解している水分および気体が半導体膜に進入して、前記色素の吸着等の増感処理を妨げることを防ぐために、あらかじめ脱気および蒸留精製しておくことが好ましい。
【０１４４】
前記色素の溶解において、好ましく用いられる溶媒はメタノール、エタノール、ｎ−プロパノールなどのアルコール系溶媒、アセトン、メチルエチルケトンなどのケトン系溶媒、ジエチルエーテル、ジイソプロピルエーテル、テトラヒドロフラン、１，４−ジオキサンなどのエーテル系溶媒、塩化メチレン、１，１，２−トリクロロエタンなどのハロゲン化炭化水素溶媒であり、特に好ましくはメタノール、エタノール、アセトン、メチルエチルケトン、テトラヒドロフラン、塩化メチレンである。
【０１４５】
《増感処理の温度、時間》
半導体を焼成した膜を形成した基板を、前記一般式（１）または（２）のいずれか１種の化合物を含む溶液に浸漬する時間は、半導体層（半導体膜）に前記化合物が深く進入して吸着等を充分に進行させ、半導体を十分に増感させ、且つ、溶液中のでの前記化合物の分解等により生成して分解物が化合物の吸着を妨害することを抑制する観点から、２５℃条件下では、３時間〜４８時間が好ましく、更に好ましくは、４時間〜２４時間である。この効果は、特に、半導体膜が多孔質構造膜である場合において顕著である。但し、浸漬時間については、２５℃条件での値であり、温度条件を変化させて場合には、上記の限りではない。
【０１４６】
浸漬しておくにあたり前記一般式（１）または（２）のいずれか１種の色素を含む溶液は、前記色素が分解しないかぎりにおいて、沸騰しない温度にまで加熱して用いてもよい。好ましい温度範囲は１０℃〜１００℃であり、更に好ましくは２５℃〜８０℃であるが、前記のとおり溶媒が前記温度範囲で沸騰する場合はこの限りでない。
【０１４７】
《光電変換素子》
本発明の光電変換素子について、図１を用いて説明する。
【０１４８】
図１は、本発明の光電変換素子の構造の一例を示す部分断面図である。
１は導電性支持体、２は感光層、３は電荷移動層、４は対向電極を表す。尚、導電性支持体１と感光層２をあわせて半導体電極ともいう。
【０１４９】
ここで、感光層２は本発明の光電変換材料用半導体を含有する層であり、電荷移動層３は通常、レドックス電解質が含有し、導電性支持体１、感光層２、対向電極４に接触した形態で用いられる。
【０１５０】
《光電変換素子の製造方法》
図１を用いながら、光電変換素子の製造方法を説明する。
【０１５１】
本発明の光電変換素子は、図１に示すような導電性支持体１上に、上記記載のように半導体薄膜を形成した後に、本発明に係る前記一般式（１）または（２）で表されるいずれか１種の色素を吸着させるという工程を経て製造される。
【０１５２】
また、半導体薄膜の表面積を増大させたり、半導体薄膜表面の不純物などを除去して、半導体の純度を高め、前記一般式（１）または（２）で表されるいずれか１種の色素から半導体への電子注入効率を高める目的で、例えば四塩化チタン水溶液を用いた化学メッキや三塩化チタン水溶液を用いた電気化学的メッキ処理を行ってもよい。
【０１５３】
導電性支持体１上に形成した半導体膜には上記記載の前記一般式（１）または（２）で表されるいずれか１種の色素を吸着させ、半導体膜を増感させて感光層２を形成する。増感処理方法は先に説明したとおり、前記化合物を適切な溶媒に溶解し、導電性支持体１上に形成された半導体膜をその溶液に浸漬することによって行われる。その際には半導体膜は、あらかじめ減圧処理したり加熱処理したりして膜中の気泡を除去し、前記一般式（１）または（２）で表されるいずれか１種の色素が半導体膜内部深くに進入できるようにしておくことが好ましい。
【０１５４】
本発明に係る半導体に、前記一般式（１）または（２）で表されるいずれか１種の色素を吸着させる際には、単独で用いてもよいし、複数を併用してもよい。さらに、従来公知の増感色素化合物（例えば、米国特許第４，６８４，５３７号、同第４，９２７，７２１号、同第５，０８４，３６５号、同第５，３５０，６４４号、同第５，４６３，０５７号、同第５，５２５，４４０号、特開平７−２４９７９０号、特開２０００−１５０００７号等に記載の化合物）とを混合して吸着させてもよい。
【０１５５】
特に、半導体の用途が太陽電池である場合、光電変換の波長域を広くして太陽光を可能な限り有効に利用できるように、二種類以上の色素を混合して用いることが好ましい。
【０１５６】
上記記載の前記一般式（１）または（２）で表されるいずれか１種の色素を複数種類併用して増感した光電変換材料用半導体は、併用する前記化合物を混合して調製した溶液に浸漬させて作製してもよいし、各々の化合物について溶液を調製し、各溶液に順に浸漬して作製することもできる。
【０１５７】
各化合物について別々の溶液を用意し、各溶液に順に浸漬して作製する場合は、半導体に前記色素や従来公知の増感色素を吸着させる順番がどのような順番であっても本発明の効果を得ることができる。
【０１５８】
吸着処理は、前記化合物が溶解した溶液を常温で用いてもよいし、また、前記化合物に影響を与えない範囲の温度まで溶液を加熱して行っても良い。更に、吸着処理時に未吸着となった色素については溶媒等の洗浄処理により除去することが好ましい。
【０１５９】
導電性支持体１上に形成した半導体膜に色素を吸着させて感光層２を形成したら、該感光層２と向かい合うようにして対向電極４を配置する。さらに、半導体電極と対向電極４の間に電荷移動層であるレドックス電解質を注入して光電変換素子とする。
【０１６０】
《太陽電池》
本発明の太陽電池について説明する。
【０１６１】
本発明の太陽電池は、図１に示すように、本発明の光電変換素子の一態様として、太陽光に最適の設計並びに、回路設計が行われ、太陽光を光源として用いたときに最適な光電変換が行われるような構造を有する。即ち、光電変換材料用半導体に太陽光が照射されうる構造となっている。本発明の太陽電池を構成する際には、前記半導体電極、電荷移動層及び対向電極をケース内に収納して封止するか、あるいはそれら全体を樹脂封止することが好ましい。
【０１６２】
本発明の太陽電池に太陽光または太陽光と同等の電磁波を照射すると、光電変換材料用半導体に吸着された本発明の化合物は、照射された光もしくは電磁波を吸収して励起する。励起によって発生した電子は半導体に移動し、次いで導電性支持体１を経由して対向電極４に移動して、電荷移動層３のレドックス電解質を還元する。一方、半導体に電子を移動させた本発明の色素化合物は酸化体となっているが、対向電極４から電荷移動層３のレドックス電解質を経由して電子が供給されることにより、還元されて元の状態に戻り、同時に電荷移動層３のレドックス電解質は酸化されて、再び対向電極４から供給される電子により還元されうる状態に戻る。このようにして電子が流れ、本発明の光電変換素子を用いた太陽電池を構成することができる。
【０１６３】
《導電性支持体》
本発明の光電変換素子や本発明の太陽電池に用いられる導電性支持体には、金属板のような導電性材料や、ガラス板やプラスチックフイルムのような非導電性材料に導電性物質を設けた構造のものを用いることができる。導電性支持体に用いられる材料の例としては金属（例えば白金、金、銀、銅、アルミニウム、ロジウム、インジウム）あるいは導電性金属酸化物（例えばインジウム−スズ複合酸化物、酸化スズにフッ素をドープしたもの）や炭素を挙げることができる。導電性支持体の厚さは特に制約されないが、０．３ｍｍ〜５ｍｍが好ましい。
【０１６４】
また導電性支持体は実質的に透明であることが好ましく、実質的に透明であるとは光の透過率が１０％以上であることを意味し、５０％以上であることがさらに好ましく、８０％以上であることが最も好ましい。透明な導電性支持体を得るためには、ガラス板またはプラスチックフイルムの表面に、導電性金属酸化物からなる導電性層を設けることが好ましい。導電性支持体１が透明である場合、光は支持体側から入射させることが好ましい。
【０１６５】
導電性支持体は表面抵抗は、５０Ω／ｃｍ^２以下であることが好ましく、１０Ω／ｃｍ^２以下であることがさらに好ましい。
【０１６６】
《電荷移動層》
本発明に用いられる電荷移動層について説明する。
【０１６７】
電荷移動層にはレドックス電解質が好ましく用いられる。ここで、レドックス電解質としては、Ｉ⁻／Ｉ_３ ⁻系や、Ｂｒ⁻／Ｂｒ_３ ⁻系、キノン／ハイドロキノン系等が挙げられる。このようなレドックス電解質は、従来公知の方法によって得ることができ、例えば、Ｉ⁻／Ｉ_３ ⁻系の電解質は、ヨウ素のアンモニウム塩とヨウ素を混合することによって得ることができる。電荷移動層はこれらレドックス電解質の分散物で構成され、それら分散物は溶液である場合に液体電解質、常温において固体である高分子中に分散させた場合に固体高分子電解質、ゲル状物質に分散された場合にゲル電解質と呼ばれる。電荷移動層として液体電解質が用いられる場合、その溶媒としては、電気化学的に不活性なものが用いられ、例えば、アセトニトリル、炭酸プロピレン、エチレンカーボネート等が用いられる。固体高分子電解質の例としては特開２００１−１６０４２７記載の電解質が、ゲル電解質の例としては『表面科学』２１巻、第５号２８８ページ〜２９３ページに記載の電解質が挙げられる。
【０１６８】
《対向電極》
本発明に用いられる対向電極について説明する。
【０１６９】
対向電極は、導電性を有するものであればよく、任意の導電性材料が用いられるが、Ｉ_３ ⁻イオン等の酸化や他のレドックスイオンの還元反応を充分な速さで行わせる触媒能を持ったものの使用が好ましい。このようなものとしては、白金電極、導電材料表面に白金めっきや白金蒸着を施したもの、ロジウム金属、ルテニウム金属、酸化ルテニウム、カーボン等が挙げられる。
【０１７０】
【実施例】
以下、実施例により本発明を説明するが、本発明はこれらに限定されない。
【０１７１】
実施例１
《光電変換素子１の作製》
下記に記載のように、図１に示すような光電変換素子を作製した。
【０１７２】
チタンテトライソプロポキシド（和光純薬社製一級）６２．５ｍｌを純水３７５ｍｌ中に室温下、激しく攪拌しながら１０分間で滴下し（白色の析出物が生成する）、次いで７０％硝酸水を２．６５ｍｌ加えて反応系を８０℃に加熱した後、８時間攪拌を続けた。さらに該反応混合物の体積が約２００ｍｌになるまで減圧下に濃縮した後、純水を１２５ｍｌ、酸化チタン粉末（昭和タイタニウム社製スーパータイタニアＦ−６）１４０ｇを加えて酸化チタン懸濁液（約８００ｍｌ）を調製した。フッ素をドープした酸化スズをコートした透明導電性ガラス板（導電性支持体１）上に該酸化チタン懸濁液を塗布し、自然乾燥の後３００℃で６０分間焼成して、支持体上に膜状の酸化チタンを形成した。
【０１７３】
ついで、メタノール溶液２００ｍｌ中に、例示化合物Ｉ−１を５ｇ溶解した溶液を調製し、上記膜状酸化チタン（光電変換材料用半導体層）を支持体ごと浸し、さらにトリフルオロ酢酸１ｇを加えて２時間超音波照射した。反応後膜状酸化チタン（光電変換材料用半導体層）をクロロホルムで洗浄し真空乾燥して、感光層２を作製した。
【０１７４】
対向電極４として、フッ素をドープした酸化スズをコートし、さらにその上に白金を担持した透明導電性ガラス板を用い、前記膜状酸化チタン感光層を形成した導電性支持体１と前記対向電極４との間に体積比が１：４であるアセトニトリル／炭酸エチレンの混合溶媒に、テトラプロピルアンモニウムアイオダイドと沃素とを、それぞれの濃度が０．４６モル／リットル、０．０６モル／リットルとなるように溶解したレドックス電解質を電荷移動層３として挿入して、光電変換素子１を作製した。
【０１７５】
《光電変換素子２〜２３の作製》
光電変換素子１の作製において、例示化合物Ｉ−１を表１に記載の化合物に変更した以外は同様にして、光電変換素子２〜２３を得た。
【０１７６】
《光電変換素子Ｒ１の作製》：比較例
光電変換素子１の作製において、例示化合物Ｉ−１を比較化合物Ｒ１に変更した以外は同様にして、光電変換素子Ｒ１を得た。
【０１７７】
【化２０】

【０１７８】
《太陽電池ＳＣ−１〜ＳＣ−２３の作製》
光電変換素子１の側面を樹脂で封入した後、リード線を取り付けて、本発明の太陽電池ＳＣ−１〜ＳＣ−２３を各々３ロットずつ作製した。
【０１７９】
《太陽電池ＳＣ−Ｒ１の作製》
上記の太陽電池ＳＣ−１の作製において、比較の光電変換素子Ｒ１を用いた以外は同様にして、太陽電池ＳＣ−Ｒ１を３ロット作製した。
【０１８０】
《太陽電池の光電変換特性評価》
上記で得られた太陽電池ＳＣ−１〜ＳＣ−２３、及び太陽電池ＳＣ−Ｒ１の各々にソーラーシミュレーター（ＪＡＳＣＯ（日本分光）製、低エネルギー分光感度測定装置ＣＥＰ−２５）により１００ｍＷ／ｍ^２の強度の光を照射した時の短絡電流密度Ｊｓｃ（ｍＡ／ｃｍ^２）および開放電圧値Ｖｏｃ（Ｖ）を測定し表１に示した。数値は、同じ構成および作製方法による太陽電池３つについての測定結果の平均値とした。
【０１８１】
【表１】

【０１８２】
表１より、比較に比べて、本発明の太陽電池は高い光電変換特性を示し、前記一般式（１）で表されるいずれか１種の化合物を用いることが有効であることがわかる。また、且つ、本発明の太陽電池ＳＣ−１〜ＳＣ−２３は、ソーラーシミュレーターによる１００ｍＷ／ｍ^２の光照射１００時間を経ても光電変換効率の低下が認められず、安定性に優れていることが明かになった。
【０１８３】
実施例２
《光電変換素子１０１〜１２１、Ｒ２の作製》
実施例１に記載の光電変換素子１の作製において、例示化合物Ｉ−１を表２に記載の化合物に変更した以外は同様にして、光電変換素子１０１〜１２１、Ｒ２を各々作製した。
【０１８４】
《太陽電池ＳＣ−１０１〜ＳＣ−１２１、ＳＣ−Ｒ２の作製》
実施例１に記載の太陽電池ＳＣ−１の作製において、光電変換素子１を表２に記載の光電変換素子を用いた以外は同様にして、太陽電池ＳＣ−１０１〜ＳＣ−１２１、ＳＣ−Ｒ２を各々、３ロットずつ作製した。
【０１８５】
《太陽電池の光電変換特性評価》
上記で得られた太陽電池ＳＣ−１０１〜ＳＣ−１２１、及び太陽電池ＳＣ−Ｒ２の各々にソーラーシミュレーター（ＪＡＳＣＯ（日本分光）製、低エネルギー分光感度測定装置ＣＥＰ−２５）により１００ｍＷ／ｍ^２の強度の光を照射した時の短絡電流密度Ｊｓｃ（ｍＡ／ｃｍ^２）および開放電圧値Ｖｏｃ（Ｖ）を測定し表２に示した。数値は、同じ構成および作製方法の太陽電池３つについての測定結果の平均値とした。
【０１８６】
【表２】

【０１８７】
【化２１】

【０１８８】
表２より、比較に比べて、本発明の太陽電池は高い光電変換特性を示し、前記一般式（２）で表されるいずれか１種の化合物を用いることが有効であることがわかる。また、且つ、本発明の太陽電池ＳＣ−１０１〜ＳＣ−１２１は、ソーラーシミュレーターによる１００ｍＷ／ｍ^２の光照射１００時間を経ても光電変換効率の低下が認められず、安定性に優れていることが明かになった。
【０１８９】
【発明の効果】
本発明により、高い光電変換効率と優れた安定性とを示す光電変換材料用半導体、光電変換素子及び太陽電池を提供することが出来た。
【図面の簡単な説明】
【図１】本発明の光電変換素子の構造の一例を示す部分断面図である。
【符号の説明】
１ 導電性支持体
２ 感光層
３ 電荷移動層
４ 対向電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor for a photoelectric conversion material, a photoelectric conversion element, and a solar cell.
[0002]
[Prior art]
A photoelectric conversion material is a material that converts light energy into electric energy using an electrochemical reaction between electrodes. When light is irradiated to the photoelectric conversion material, electrons are generated on one electrode side and move to the counter electrode. The electrons that have moved to the counter electrode move as ions in the electrolyte and return to one electrode.
[0003]
That is, the photoelectric conversion material is a material from which light energy can be continuously extracted as electric energy, and is used for, for example, a solar cell. Although there are several types of solar cells, most of the solar cell used in home-use power generation panels, desktop calculators, clocks, portable game machines, and the like are silicon solar cells.
[0004]
However, recently, dye-sensitized solar cells have attracted attention and have been studied for practical use. Dye-sensitized solar cells have been studied for a long time, and the basic structure thereof specifically includes a metal oxide semiconductor and a dye adsorbed thereon, an electrolyte solution, and a counter electrode.
[0005]
In the conventional dye-sensitized solar cell as described above, a photoelectric conversion material in which a spectral sensitizing dye having absorption in a visible light region is adsorbed on a semiconductor surface is used. For example, a solar cell having a spectral sensitizing dye layer such as a transition metal complex on the surface of a metal oxide semiconductor is described (for example, see Patent Document 1), or a titanium oxide semiconductor doped with metal ions. One that describes a solar cell having a spectral sensitizing dye layer such as a transition metal complex on the surface of the layer (for example, see Patent Document 2).
[0006]
On the other hand, as an oxide semiconductor electrode having photoelectric conversion ability, a semiconductor single crystal electrode has been used in the early days. The type is titanium oxide (TiO 2).₂), Zinc oxide (ZnO), tin oxide (SnO)₂).
[0007]
However, the single crystal electrode has the disadvantage that the efficiency of the single crystal electrode is very low due to the small amount of dye adsorbed and the cost is high. Thus, a high surface area semiconductor electrode having a large number of pores formed by sintering fine particles has been devised.
[0008]
For example, Tsubomura et al. Report that a porous zinc oxide electrode having an organic dye adsorbed thereon has very high performance (for example, see Non-Patent Document 1).
[0009]
Since then, dyes have also been improved, and Graetzel et al. Now adsorb ruthenium complex dyes onto porous titanium oxide electrodes, which now have performance comparable to silicon solar cells (eg, , Non-Patent Document 2).
[0010]
However, in order to replace silicon solar cells and put them into practical use, higher energy conversion efficiency, higher short-circuit current, open-circuit voltage, and form factor are required. The substances reported in are ZnO, TiO₂, Zirconium oxide (ZrO₂), Niobium oxide (Nb₂O₅) Etc. are being developed.
[0011]
In addition, the dye-sensitized wet-type solar cell has a very low manufacturing cost as compared with the silicon solar cell, and may possibly replace the silicon solar cell used in the above-described various products in the future. In that case, the characteristics of the solar cell corresponding to each product become important. Among the characteristics of solar cells, there are various
1. Short-circuit current
2. Open circuit voltage
3. Form factor
4. Energy conversion efficiency
5. Optical absorption spectrum
Are important, but especially 4. Energy conversion efficiency is the biggest problem of solar cells, and improvement thereof has been strongly desired. As one of the technical issues that affect the efficiency, a sensitizing dye having the ability to efficiently transfer photoexcited electrons to a semiconductor is required. Among the various dyes examined so far, the ruthenium complex dye is known to have relatively excellent properties, but the dye is expensive, and ruthenium, the central metal of the complex, is a rare element. Therefore, there is a concern about stable supply in the future, and therefore, an organic dye that can be supplied stably at a lower cost is more preferable. From such demands, many organic dyes have been studied so far, but the photoelectric conversion efficiency is not yet sufficient, and an organic dye capable of forming a photoelectric conversion element with higher conversion efficiency has been long-awaited.
[0012]
Various dyes have been studied in addition to ruthenium complex dyes, but well-known are merocyanine dyes, xanthene dyes, coumarin dyes, acridine dyes, phenylmethane dyes, squarylium dyes, etc. It is. Squarylium dyes are also described in, for example, JP-A-2000-106224, JP-A-2000-277180, JP-A-2000-299139, and JP-A-2001-6761, and squaric acid compounds are described in JP-A-2000-251958. The conversion efficiency is not yet sufficient, and an organic dye capable of forming a photoelectric conversion element with higher conversion efficiency has been desired.
[0013]
[Patent Document 1]
JP-A-1-220380
[0014]
[Patent Document 2]
Japanese Patent Publication No. Hei 5-504023
[0015]
[Non-patent document 1]
Nature, 261 (1976) p402
[0016]
[Non-patent document 2]
J. Am. Chem. Soc. 115 (1993) 6382
[0017]
[Problems to be solved by the invention]
A first object of the present invention is to provide a semiconductor for a photoelectric conversion material, a photoelectric conversion element, and a solar cell having high photoelectric conversion efficiency and excellent stability.
[0018]
[Means for Solving the Problems]
The above object of the present invention has been achieved by the following constitutions 1 to 8.
[0019]
1. A semiconductor for a photoelectric conversion material, comprising a dye represented by the general formula (1).
[0020]
2. A semiconductor for a photoelectric conversion material, comprising a dye represented by the general formula (2).
[0021]
3. 3. The photoelectric conversion material as described in 1 or 2, wherein the ring formed by including the atomic group Z or Z ′ of the dye represented by the general formula (1) or (2) is a 5-membered ring. For semiconductor.
[0022]
4. Wherein the ring structure formed by including the atomic group Z or Z 'of the dye represented by the general formula (1) or (2) is represented by the general formulas a to d. The semiconductor for a photoelectric conversion material according to 1.
[0023]
5. The ring structure formed containing Z or Z 'of the dye represented by the general formula (1) or (2) is represented by the general formulas (Cp-1), (Cp-2), (Cp-3), 3. The semiconductor for a photoelectric conversion material as described in 1 or 2 above, which is represented by (Cp-5), (Cp-13), (Cp-14) or (Cp-15).
[0024]
6. The semiconductor for a photoelectric conversion material according to any one of the above 1 to 5, wherein the semiconductor for a photoelectric conversion material is a metal oxide or a metal sulfide semiconductor.
[0025]
7. 7. A photoelectric conversion element, wherein a photosensitive layer containing the semiconductor for a photoelectric conversion material according to any one of 1 to 6 is provided on a conductive support.
[0026]
8. A solar cell having the photoelectric conversion element, the charge transfer layer, and the counter electrode according to the above item 7.
[0027]
Hereinafter, the present invention will be described in detail.
The present inventors have conducted intensive studies in order to solve the above-described problems, and as a result, have found a specific structure represented by the general formula (1) or (2) described in each of claims 1 to 5. By using a semiconductor for a photoelectric conversion material sensitized with a compound having the same, a semiconductor for a photoelectric conversion material that exhibits the effects described in the present invention, that is, high photoelectric conversion efficiency and excellent stability, was successfully obtained.
[0028]
《Semiconductor for photoelectric conversion materials》
Examples of the semiconductor used for the semiconductor for a photoelectric conversion material of the present invention include simple substances such as silicon and germanium, and Group 3 to Group 5 and Group 13 to Group 15 systems of the periodic table (also referred to as the periodic table of elements). A compound having an element, a chalcogenide of a metal (eg, oxide, sulfide, selenide, or the like), a metal nitride, or the like can be used.
[0029]
Preferred metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, or tantalum oxide, cadmium, zinc, lead, silver, antimony or Examples include bismuth sulfide, cadmium or lead selenide, and cadmium telluride. Other compound semiconductors include phosphides of zinc, gallium, indium, cadmium and the like, selenides of gallium-arsenic or copper-indium, sulfides of copper-indium, nitrides of titanium, and the like.
[0030]
Specific examples of the semiconductor according to the semiconductor for a photoelectric conversion material of the present invention include TiO.₂, SnO₂, Fe₂O₃, WO₃, ZnO, Nb₂O₅, CdS, ZnS, PbS, Bi₂S₃, CdSe, CdTe, GaP, InP, GaAs, CuInS₂, CuInSe₂, Ti₃N₄Etc., but preferably used is TiO 2₂, ZnO, SnO₂, Fe₂O₃, WO₃, Nb₂O₅, CdS and PbS, more preferably TiO 2₂Or Nb₂O₅Of these, TiO 2 is preferably used.₂It is.
[0031]
As the semiconductor used for the semiconductor for a photoelectric conversion material of the present invention, a plurality of the above-described semiconductors may be used in combination. For example, several types of the above-mentioned metal oxides or metal sulfides can be used in combination, and 20% by mass of titanium nitride (Ti₃N₄) May be used as a mixture. Also, J.I. Chem. Soc. Chem. Commun. , 15 (1999). At this time, when a component other than the metal oxide or the metal sulfide is added as the semiconductor, the mass ratio of the additional component to the metal oxide or the metal sulfide semiconductor is preferably 30% or less.
[0032]
By subjecting the semiconductor for a photoelectric conversion material described above to a sensitization treatment with any one of the dyes represented by the general formulas (1) and (2), one of the objects according to the present invention is high photoelectric conversion. The semiconductor for a photoelectric conversion material of the present invention having efficiency and excellent stability can be obtained.
[0033]
Hereinafter, the dyes represented by the general formulas (1) and (2) will be described.
<< Dyes Represented by General Formulas (1) and (2) >>
The dyes represented by the general formulas (1) and (2) according to the present invention will be described.
[0034]
Z and Z 'each independently represent an atomic group necessary for the dyes represented by the general formulas (1) and (2) to have absorption in the visible and / or near infrared regions, and have a substituent. May be bonded with a substituent to form a condensed ring, at least one of which has a carboxyl group or a substituent having a carboxyl group;₁And B₂Are each independently -C (R₁) R₂-Or -NR₃-Represents R₁And R₂Each independently represents a hydrogen atom or a substituent.
[0035]
The substituent is not particularly limited as long as it can be substituted. For example, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group) , Tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), bicycloalkyl group (eg, bicyclo [1,2,2] heptane-2-yl group, bicyclo [2 , 2,2] octan-3-yl group), alkenyl group (eg, vinyl group, allyl group, prenyl group, octenyl group, etc.), cycloalkenyl group (eg, 2-cyclopenten-1-yl group, 2-cyclohexen-1-yl group, etc.), bicycloalkenyl group (for example, bicyclo [2,2,1] hept-2) Ene-1-yl group, bicyclo [2,2,2] oct-2-en-4-yl group, etc.), alkynyl group (eg, propargyl group, ethynyl group, trimethylsilylethynyl group, etc.), aryl group (eg, Phenyl group, naphthyl group, p-tolyl group, m-chlorophenyl group, o-hexadecanoylaminophenyl group, etc., heterocyclic group (for example, pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group) , Pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), heterocyclic oxy group (for example, 1-phenyltetrazole-5-oxy group, 2-tetrahydropyranyloxy) Group, pyridyloxy group, thiazolyloxy group, oxazolyloxy group, a Dazolyloxy group, etc.), halogen atom (eg, chlorine atom, bromine atom, iodine atom, fluorine atom, etc.), alkoxy group (eg, methoxy group, ethoxy group, propyloxy group, tert-butoxy group, pentyloxy group, hexyloxy) Group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, 2-methylphenoxy group, 4-tert) -Butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), Cycloalkyl Ruthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), heterocyclic thio group (eg, pyridylthio group, thiazolylthio group, oxazolylthio group, imidazolylthio group, furylthio group , A pyrrolylthio group, etc.), an alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), an aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxy group) Carbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, Rohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc., ureido group (for example, methylureido group, ethylureido group, pentylureido group) , Cyclohexylureido, octylureido, dodecylureido, phenylureido, naphthylureido, 2-pyridylaminoureido, etc.), acyl (eg, acetyl, ethylcarbonyl, propylcarbonyl, pentylcarbonyl, cyclohexyl) Carbonyl, octylcarbonyl, 2-ethylhexylcarbonyl, dodecylcarbonyl, phenylcarbonyl, naphthylcarbonyl, pyridylcarbonyl, etc.), Loxy group (for example, formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy Group, phenylcarbonyloxy group, etc.), acylamino group (eg, acetylamino group, benzoylamino group, formylamino group, pivaloylamino group, lauroylamino group, 3,4,5-tri-n-octyloxyphenylcarbonylamino group, etc.) ), Amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group) Amino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc., carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group) Propylaminocarbonyl, pentylaminocarbonyl, cyclohexylaminocarbonyl, octylaminocarbonyl, 2-ethylhexylaminocarbonyl, dodecylaminocarbonyl, phenylaminocarbonyl, naphthylaminocarbonyl, 2-pyridylaminocarbonyl, etc.) , An alkylsulfinyl group or an arylsulfinyl group (for example, a methylsulfinyl group, an ethylsulfinyl group, a butylsulfinyl group, Hexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc., alkylsulfonyl group or arylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl) Group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, methylamino group, ethylamino group, dimethylamino) Group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, N-methylanilino group, diphenylamino group, naphthylami Group, 2-pyridylamino group, etc.), silyloxy group (eg, trimethylsilyloxy group, tert-butyldimethylsilyloxy group, etc.), aminocarbonyloxy group (eg, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyl) An oxy group, a morpholinocarbonyloxy group, an N, N-di-n-octylaminocarbonyloxy group, an Nn-octylcarbamoyloxy group, etc., an alkoxycarbonyloxy group (for example, a methoxycarbonyloxy group, an ethoxycarbonyloxy group, tert-butoxycarbonyloxy group, n-octylcarbonyloxy group, etc., aryloxycarbonyloxy group (for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyf Methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group, etc. ), An aryloxycarbonylamino group (for example, a phenoxycarbonylamino group, a p-chlorophenoxycarbonylamino group, a mn-octyloxyphenoxycarbonylamino group, etc.), a sulfamoylamino group (for example, a sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group, etc., mercapto group, arylazo group (for example, phenylazo group, naphthylazo group, p-chlorophenylazo group, 5-ethyl A thio-1,3,4-thiadiazol-2-ylazo group, a heterocyclic azo group (eg, a pyridylazo group, a thiazolylazo group, an oxazolylazo group, an imidazolylazo group, a furylazo group, a pyrrolylazo group), an imino group (eg, N Succinimido-1-yl group, N-phthalimido-1-yl group, etc.), phosphino group (eg, dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group, etc.), phosphinyl group (eg, phosphinyl group, Dioctyloxyphosphinyl group, diethoxyphosphinyl group, etc.), phosphinyloxy group (eg, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, etc.), phosphinylamino group (eg, Dimethoxyphosphinylamino group, dimethylaminophosphinyl Amino group etc.), a silyl group (e.g., trimethylsilyl group, tert- butyldimethylsilyl group, phenyldimethylsilyl group, etc.), a cyano group, a nitro group, a hydroxyl group, a sulfo group, a carboxyl group.
[0036]
In the general formulas (1) and (2), the ring structure formed together with Z and Z ′ (hereinafter, also referred to as Q and Q ′) is preferably a 5- or 6-membered ring, preferably a 5- or 6-membered ring. Examples of the aromatic carbon ring include a benzene ring, a naphthalene ring, an indene ring, a tetralin ring, an anthracene ring, and a phenanthrene ring.
[0037]
In the general formulas (1) and (2), as the 5- or 6-membered heterocyclic ring formed together with Z and Z ′, an aromatic heterocyclic ring (for example, a furan ring, a pyrrole ring, a pyrazole ring, an imidazole ring, Oxazole ring, thiazole ring, 1,2,3-oxadiazole ring, 1,2,3-triazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, benzofuran ring, indole ring, benzothiophene ring, benzimidazole Ring, benzothiazole ring, purine ring, quinoline ring and isoquinoline ring) and heterocycle (pyran ring, chromene ring, xanthene ring, carbazole ring, β-carboline ring, isochroman ring, chroman ring, pyrrolidine ring, pyrroline ring, imidazo Lysine ring, imidazoline ring, pyrazolidine ring, pyrazoline ring, piperidine ring, piperazine ring Indoline ring, isoindoline ring, quinuclidine ring, morpholine ring, etc.).
[0038]
The aromatic carbocyclic ring and heterocyclic ring may be a single ring or a condensed ring, may further have a substituent, and has at least one carboxyl group or a substituent having a carboxyl group.
[0039]
Further, in addition to the compounds represented by the above general formulas (1) and (2), ions and salts derived from the compounds are included. For example, when the compounds represented by the general formulas (1) and (2) have a sulfo group in the molecular structure, in addition to the compound, an anion generated by dissociation of the sulfo group and the anion And a counter cation.
[0040]
Such a salt may be a salt formed with a metal ion such as a sodium salt, a potassium salt, a magnesium salt, a calcium salt, or a salt formed with an organic base such as pyridine, piperidine, triethylamine, aniline, and diazabicycloundecene. It may be a formed salt. Similarly, in the case of a compound having a basic group in the molecule, a cation generated by protonation of the compound, and a hydrochloride, sulfate, acetate, methyl sulfonate, p-toluene sulfonate, etc. An inner salt formed with an acid is also included.
[0041]
Next, the ring structure (Q, Q ') formed together with Z and Z' will be described in more detail.
[0042]
Q and Q ′ may be independently the same or different, and a ring structure (partial structure) represented by the following general formulas (Cp-1) to (Cp-26) It is preferably used.
[0043]
Here, the atomic groups represented by (Cp-1) to (Cp-26) are, at the positions indicated by *, a part other than Q and Q '(squarylium ring or croconium ring) in the general formula (2). Are combined. Q and Q 'according to the present invention are not limited by these.
[0044]
Embedded image

[0045]
Embedded image

[0046]
Hereinafter, the compounds represented by formulas (Cp-1) to (Cp-26) will be described in detail.
[0047]
<< General formula (Cp-1) >>
In the general formula (Cp-1), R₆₁Represents an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an amino group, a carboxyl group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, a ureido group or an alkoxycarbonylamino group. R₆₂Represents an alkyl group, an aryl group or a heterocyclic group.
[0048]
Where R₆₁, R₆₂Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0049]
Where R₆₁Examples of the group represented by preferably include an alkyl group, an aryl group, an acylamino group, an amino group, a ureido group, an alkoxycarbonylamino group, a carboxyl group, and more preferably, an aryl group, an acylamino group, and an anilino group. , A carboxyl group.
[0050]
Where R₆₂The group represented by is preferably an aryl group or a heterocyclic group, and is more preferably an aryl group.
[0051]
<< General formula (Cp-2), General formula (Cp-3) >>
In the general formulas (Cp-2) and (Cp-3), R₆₃, R₆₄Represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, an amino group, an alkylamino group, an alkylthio group, an arylthio group, an alkoxyl group, and an aryloxy group. Represents a group, a ureido group, an alkoxycarbonylamino group, a carbamoyl group, a carboxyl group or an alkoxycarbonyl group.
[0052]
Where R₆₃, R₆₄Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0053]
Where R₆₃Examples of the group represented by preferably include an alkyl group, an aryl group, a carboxyl group, an alkoxyl group, and a carbamoyl group, and more preferably a methyl group, a tert-butyl group, and a carboxyl group.
[0054]
Where R₆₄The group represented by is preferably an alkyl group, an alkenyl group, or an aryl group.
[0055]
<< General formula (Cp-4), General formula (Cp-5) >>
In the general formulas (Cp-4) and (Cp-5), R₆₃And R₆₅Represents R represented by the formulas (Cp-2) and (Cp-3).₆₃And R₆₄Is synonymous with
[0056]
R₆₆And R₆₇Is a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, an amino group, an alkylthio group, an arylthio group, an alkoxyl group, an aryloxy group, an ureido group, an alkoxy group, respectively. Represents a carbonylamino group, an acyl group, a carboxyl group, an alkoxycarbonyl group or a carbamoyl group.
[0057]
Where R₆₅, R₆₆And R₆₇Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0058]
Where R₆₅The group represented by preferably includes an alkyl group, an aryl group, an alkoxyl group, an aryloxy group and the like.₆₃, R₆₆, R₆₇Preferred examples of the groups include a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, an alkoxycarbonyl group, and a carbamoyl group.
[0059]
<< General formula (Cp-6) >>
In the general formula (Cp-6), R₆₈And R₆₉Are hydrogen, alkyl, aryl, heterocyclic, acylamino, alkylsulfonyl, arylsulfonylamino, amino, alkylthio, arylthio, alkoxyl, aryloxy, ureido, alkoxycarbonylamino, respectively. A carboxyl group, an acyl group, an alkoxycarbonyl group or a carbamoyl group.
[0060]
Where R₆₈, R₆₉Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0061]
Where R₆₈, R₆₉The group represented by preferably includes a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, and the like.
[0062]
<< General formula (Cp-7), (Cp-8), (Cp-9), (Cp-10) >>
In the general formulas (Cp-7), (Cp-8), (Cp-9), and (Cp-10), R₇₀, R₇₁Is a halogen atom, an alkyl group, an aryl group, a heterocyclic group, a silyl group, an acylamino group, an alkylsulfonyl group amino group, an arylsulfonylamino group, an amino group, a ureido group, an alkylthio group, an arylthio group, an alkoxyl group, a carboxyl group or R represents an alkoxycarbonylamino group;₇₂And R₇₃Represents a hydrogen atom or an alkyl group, a represents an integer of 0 to 3, b represents an integer of 0 to 2, and c represents an integer of 0 to 4. When a, b, or c is plural, a plurality of R₇₀May be the same or different.
[0063]
Where R₇₀, R₇₁, R₇₂, R₇₃Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0064]
Where R₇₀The group represented by is preferably a halogen atom, an alkyl group, an aryl group, a carboxyl group,₇₁The group represented by preferably includes a halogen atom, an alkyl group, an acylamino group, a carbamoyl group, a carboxyl group, and the like.₇₂, R₇₃Examples of the group represented by each include a hydrogen atom, a methyl group, and an ethyl group. Also, preferably, a represents 1 or 2, b represents 1 or 2, and c represents an integer of 0 to 2.
[0065]
<< General formula (Cp-11) >>
In the general formula (Cp-11), R₇₄Represents a carbamoyl group, an alkoxycarbonyl group, a carboxyl group, a cyano group, a sulfamoyl group, an acylamino group, a ureido group, an alkoxycarbonylamino group or an alkyl or arylsulfonylamino group;₇₅Is a halogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkyl or arylsulfonylamino group, an amino group, an alkylthio group, an arylthio group, an alkoxyl group, an aryloxy group, a carboxyl group, a ureido group or an alkoxycarbonylamino group And d represents an integer of any of 0 to 4. When d is plural, plural R₇₅May be the same or different.
[0066]
Where R₇₄, R₇₅Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0067]
Where R₇₄The group represented by is preferably a carbamoyl group, a sulfamoyl group, an acylamino group, a carboxyl group,₇₅The group represented by is preferably an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a ureido group, or an alkoxycarbonylamino group, and d is 0 or 1.
[0068]
<< General formula (Cp-12) >>
In the general formula (Cp-12), R₈₂, R₈₃, R₈₄Is a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkyl or arylsulfonylamino group, an amino group, an alkylthio group, an arylthio group, an alkoxy group, an aryloxy group, a ureido group, an alkoxycarbonylamino group, Represents an acyl group, a carboxyl group, an alkoxycarbonyl group or a carbamoyl group.
[0069]
Where R₈₂, R₈₃, R₈₄Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0070]
R₈₂, R₈₃, R₈₄Each of the groups represented by preferably represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a carboxyl group, an alkoxy group, or the like.
[0071]
<< General formula (Cp-13) >>
In the general formula (Cp-13), R₈₅, R₈₆Is a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, an amino group, an alkylthio group, an arylthio group, an alkoxyl group, an aryloxy group, an ureido group, an alkoxy group, respectively. Represents a carbonylamino group, an acyl group, a carboxyl group, an alkoxycarbonyl group or a carbamoyl group.
[0072]
Where R₈₅, R₈₆Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0073]
Where R₈₅, R₈₆Each of the groups preferably represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a carboxyl group, or the like.
[0074]
<< General formula (Cp-14), (Cp-15), (Cp-16), (Cp-17), (Cp-18) >>
In the general formulas (Cp-14) to (Cp-18), R₈₇, R₈₈Represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carboxyl group, a cyano group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, or a nitro group, R₈₉, R₉₀Represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group, respectively.
[0075]
Where R₈₇, R₈₈, R₈₉, R₉₀In the above, each of the groups has the same meaning as the group in the description of the substituent.
[0076]
Where R₈₇The group represented by is preferably a carbamoyl group, an alkoxycarbonyl group, a carboxyl group, a cyano group and the like, and more preferably a carboxyl group and a cyano group. R₈₈The group represented by is a carbamoyl group, a carboxyl group, an alkoxycarbonyl group, a cyano group, an alkylsulfonyl group, an arylsulfonyl group and the like, and more preferably an alkoxycarbonyl group and a carboxyl group. R₈₉, R₉₀The groups represented by each are preferably an alkyl group, an aryl group, and the like, and more preferably an aryl group.
[0077]
<< General formulas (Cp-19) to (Cp-26) >>
In the general formulas (Cp-19) to (Cp-26), R₉₁, R₉₂Represents an alkyl group, an aryl group, a heterocyclic group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carboxyl group, a cyano group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a nitro group,₉₃, R₉₄, R₉₅Is a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, a ureido group, an alkoxycarbonylamino group, an alkyl or arylsulfonylamino group, a halogen atom, a carboxyl group, an amino group, an alkylthio group, an arylthio group, and an alkoxyl, respectively. Group or an aryloxy group.
[0078]
Where R₉₁, R₉₂, R₉₃, R₉₄, R₉₅Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0079]
Where R₉₁The group represented by is preferably an aryl group, a heterocyclic group, a carbamoyl group, an alkoxycarbonyl group, a carboxyl group, a cyano group, and the like.₉₂The group represented by is preferably a carbamoyl group, an alkoxycarbonyl group, a carboxyl group, a cyano group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, and the like.₉₃, R₉₄, R₉₅Each of the groups represented by preferably represents a hydrogen atom, an alkyl group, an acylamino group, a halogen atom, a carboxyl group, an amino group, an alkylthio group, an arylthio group, or the like.
[0080]
Among the groups represented by the general formulas (Cp-1) to (Cp-26), the ring structure sites Q and Q ′ according to the present invention include a general formula (Cp-1) which forms a 5-membered ring with little steric hindrance. (Cp-1) to (Cp-6) and (Cp-13) to (Cp-26) are preferred.
[0081]
Further, the ring structure sites Q and Q 'are preferably represented by the aforementioned general formulas a to d.
[0082]
In the general formulas a to d, R₄And R₅Represents a hydrogen atom or a substituent;₂Represents an atomic group necessary for forming a 5- or 6-membered ring, may have a substituent, may be bonded by a substituent to form a condensed ring, and * represents a group other than Q or Q '. Combine with the part. Further, at least one of the ring structures has a carboxyl group or a substituent having a carboxyl group. R₄And R₅The substituent represented by has the same meaning as the substituent described above.
[0083]
Z₂More specifically, for example, in the case of general formula a, compounds represented by general formulas a-1 to a-9 and the like can be mentioned.
[0084]
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[0085]
General formulas a-1 to a-3 and a-6 to a-9 are the same as general formulas (Cp-2) to (Cp-4) and (Cp-23) to (Cp-26) described above, In general formulas a-1 to a-3, R₄Is R in the above general formulas (Cp-2) to (Cp-4)₆₃And R in the general formulas a-1 and a-2₆Is R in the above general formulas (Cp-2) to (Cp-3)₆₄And R in general formula a-3₆Is R₆₅And R₇Is also R₆₆Is synonymous with
[0086]
Further, R in the general formulas a-4 and a-5₄, R₆, R₇For R₆₄Is synonymous with
[0087]
R in general formulas a-6 to a-9₄Is R in the above general formulas (Cp-23) to (Cp-26)₉₁Has the same meaning as in general formulas a-6 and a-8,₆Is R in the above general formulas (Cp-23) to (Cp-26)₉₃Has the same meaning as that of R in general formula a-6₇Is R in the above general formulas (Cp-23) to (Cp-26)₉₄Has the same meaning as in general formulas a-7 and a-9,₇Is R in the above general formulas (Cp-23) to (Cp-26)₉₅Is synonymous with
[0088]
Among these, the structures of general formulas a-1, a-2, a-3, a-6 and a-7 are preferable, and the structures of general formulas a-1, a-3 and a-6 are more preferable.
[0089]
Preferred general ring structures having a similar structure are also used in formulas b to d. For example, for general formula b, general formulas (Cp-16), (Cp-18), (Cp-20) and (Cp-22), and for general formula c, general formulas (Cp-14) and (Cp-15) ), (Cp-17), (Cp-19) and (Cp-21), and the general formula d includes general formulas (Cp-5) to (Cp-6), but is not limited thereto. There is no.
[0090]
In the compounds according to the present invention, each represented by the general formula (1) or (2), each of the ring structures Q and Q ′ is a 5-membered ring (Cp-1) to (Cp-6); (Cp-13) to (Cp-26) are preferred, and particularly preferably used are those having a pyrazolone compound having the general formula (Cp-1), or having the general formula (Cp-2) or (Cp-3). Pyrazoloazole compounds and imidazole compounds having the general formulas (Cp-5) and (Cp-13) Pyrrolotriazole compounds having the general formulas (Cp-14) and (Cp-15) are preferable.
[0091]
Hereinafter, specific examples of the compound represented by Formula (1) or (2) according to the present invention are shown, but the present invention is not limited thereto.
[0092]
First, specific examples of the structure represented by Q or Q 'are shown below, but the present invention is not limited thereto.
[0093]
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[0094]
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[0095]
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[0096]
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[0097]
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[0098]
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[0099]
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[0100]
Embedded image

[0101]
Next, specific examples of the dye structure are shown, but the invention is not limited thereto.
[0102]
Embedded image

[0103]
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[0104]
The dye (compound) represented by the general formula (1) or (2) according to the present invention is described in, for example, JP-A-10-204310, JP-A-2000-265077, JP-A-2000-345059, The compound can be synthesized with reference to a conventionally known method described in JP-A-2002-80764 and the like.
[0105]
Specific examples of the synthesis method are shown below, but other dyes (compounds) can be synthesized in the same manner, and the synthesis method is not limited to these.
[0106]
Synthesis Example 1
(Synthesis of Exemplified Compound I-6)
(1) Synthesis route
[0107]
Embedded image

[0108]
(2) Synthesis of Exemplified Compound I-6
After 0.37 g of Intermediate 2 and 12 ml of n-butanol were heated to reflux to completely dissolve, a solution of 1.50 g of Intermediate 1 dissolved in 10 ml of n-butanol was added, and the mixture was refluxed for 5 hours. After completion of the reaction, the mixture was cooled and recrystallized as it was to obtain 0.92 g of Exemplified Compound I-6. It was identified by MASS, H-NMR, and IR spectrum, and it was confirmed that it was a target. The absorption maximum of this compound in methanol was 550 nm.
[0109]
Synthesis Example 2
(Synthesis of Exemplified Compound II-10)
(1) Synthesis route
[0110]
Embedded image

[0111]
(2) Synthesis of Exemplified Compound II-10
4.00 g of Intermediate 3 and 1.40 g of Intermediate 4 are added to 15 ml of n-butanol and 15 ml of toluene, and the mixture is refluxed for 1 hour. After completion of the reaction, the mixture was cooled, and acetonitrile was added for recrystallization to obtain 2.11 g of Exemplified Compound II-10. It was identified by MASS, H-NMR, and IR spectrum, and it was confirmed that it was a target. The absorption maximum of this compound in methanol was 660 nm.
[0112]
《Sensitization of semiconductors for photoelectric conversion materials》
The semiconductor for a photoelectric conversion material of the present invention is sensitized by containing any one of the dyes represented by the general formula (1) or (2), and can exhibit the effects described in the present invention. Become. Here, the term “containing the dye” refers to various modes such as adsorption to the semiconductor surface, and when the semiconductor has a porous structure such as a porous structure, the compound enters the porous structure of the semiconductor.
[0113]
1 m of semiconductor layer (may be a semiconductor)²The total content of each dye represented by the above general formula (1) or (2) is preferably in the range of 0.01 to 100 mmol, more preferably 0.1 to 50 mmol. Particularly preferably, it is 0.5 mmol to 20 mmol.
[0114]
When sensitizing treatment is performed using any one of the dyes represented by the general formula (1) or (2) according to the present invention, the dye may be used alone, or a plurality of dyes may be used in combination. Also, any one of the dyes represented by the general formula (1) or (2) according to the present invention and another compound (for example, U.S. Patent Nos. 4,684,537 and 4,927, Nos. 721, 5,084,365, 5,350,644, 5,463,057, 5,525,440 and the like. Compounds described in the respective specifications, JP-A-7-249790, JP-A-2000-150007 and the like can also be used as a mixture.
[0115]
In particular, when the application of the semiconductor for a photoelectric conversion material of the present invention is a solar cell to be described later, two types having different absorption wavelengths are used so that the wavelength region of the photoelectric conversion is made as wide as possible and sunlight can be used effectively. It is preferable to use a mixture of the above dyes.
[0116]
In order for the semiconductor to contain any one of the dyes represented by the general formula (1) or (2), the compound is dissolved in an appropriate solvent (such as ethanol) and thoroughly dried in the solution. A method of immersing a semiconductor for a long time is general.
[0117]
When preparing a semiconductor for a photoelectric conversion material in which a plurality of any one of the dyes represented by the general formula (1) or (2) are used in combination, or in combination with another sensitizing dye compound, May be prepared and used, or a solution may be prepared for each compound and immersed in each solution in order. When preparing a separate solution for each compound and immersing it in each solution in order, the effects described in the present invention are obtained regardless of the order in which the semiconductor or the compound or the sensitizing dye is included. be able to. Alternatively, a semiconductor for a photoelectric conversion material may be manufactured by mixing semiconductor fine particles having the dye or compound alone adsorbed thereon.
[0118]
The adsorption treatment may be performed when the semiconductor is in the form of particles, or may be performed after forming a film on the support. A solution in which a dye or a compound used for the adsorption treatment is dissolved may be used at normal temperature or may be used by heating at a temperature in which the compound does not decompose and the solution does not boil. In addition, the adsorption of the compound may be performed after the application of the semiconductor fine particles (after the formation of the photosensitive layer) as in the production of a photoelectric conversion element described later. Alternatively, the dye may be adsorbed by simultaneously applying the semiconductor fine particles and the dye of the present invention. The unadsorbed dye can be removed by washing.
[0119]
In the sensitization treatment of the semiconductor for a photoelectric conversion material of the present invention, the sensitization treatment is performed by including one of the dyes represented by the general formula (1) or (2) in the semiconductor. However, the details of the sensitization process will be specifically described in a photoelectric conversion element described later.
[0120]
Further, in the case of a semiconductor for a photoelectric conversion material having a semiconductor thin film having a high porosity, the dye or the compound or the like is used before the water is adsorbed on the semiconductor thin film by the moisture, water vapor, or the like, as well as in the void inside the semiconductor thin film. It is preferable to complete the adsorption treatment of the sensitizing dye or the like (sensitization treatment of the semiconductor for a photoelectric conversion material).
[0121]
The semiconductor for a photoelectric conversion material of the present invention may be subjected to a surface treatment using an organic base. Examples of the organic base include diarylamine, triarylamine, pyridine, 4-t-butylpyridine, polyvinylpyridine, quinoline, piperidine, amidine and the like, among which pyridine, 4-t-butylpyridine and polyvinylpyridine are exemplified. preferable.
[0122]
When the organic base is a liquid, the solution is dissolved in an organic solvent in the case of a solid, and a solution prepared in an organic solvent is prepared. .
[0123]
Further, as the dye which can be used in combination with any one of the dyes represented by the general formula (1) or (2) according to the present invention, a dye which can spectrally sensitize the semiconductor according to the present invention. Then, any dye can be used. In order to widen the wavelength range of photoelectric conversion as much as possible and to increase the conversion efficiency, it is preferable to mix two or more dyes. The dyes to be mixed and their proportions can be selected so as to match the wavelength range and intensity distribution of the target light source.
[0124]
Dyes that can be used in combination in the present invention include metal complex dyes, phthalocyanine dyes, porphyrin dyes, and polymethine dyes from a comprehensive viewpoint such as photoelectron transfer reaction activity, light durability, and photochemical stability. Is preferably used.
[0125]
Among the metal complex dyes, JP-A-2001-223037, JP-A-2001-226607, U.S. Pat. Nos. 4,927,721, 4,684,537, 5,084,365, and Nos. 5,350,644, 5,463,057, 5,525,440, JP-A-7-249750, JP-T-10-504512, and World Patent 98/050393. Ruthenium complex dyes are preferably used.
[0126]
As the porphyrin dye and the phthalocyanine dye, the dyes described in JP-A-2001-223037 are preferable.
[0127]
Examples of the polymethine dyes include conventionally known methine dyes, JP-A-11-35836, JP-A-11-158395, JP-A-11-163378, JP-A-11-214730, JP-A-11-214731, JP-A-10-93118, JP-A-11-273754, JP-A-2000-106224, JP-A-2000-357809, JP-A-2001-52766, European Patent Nos. 892,411, and 911,841. What is described is mentioned.
[0128]
<< Method of manufacturing semiconductor for photoelectric conversion material >>
A method for manufacturing a semiconductor for a photoelectric conversion material of the present invention will be described.
[0129]
One embodiment of the semiconductor for a photoelectric conversion material of the present invention includes a method of forming the above-described semiconductor for a photoelectric conversion material on a conductive support by firing.
[0130]
When the semiconductor for a photoelectric conversion material of the present invention is produced by firing, the sensitization (adsorption, penetration into porous material, etc.) of the semiconductor using the above-mentioned dye or sensitizing dye is performed after firing. Is preferred. It is particularly preferable to perform the compound adsorption treatment quickly after the firing and before water is adsorbed on the semiconductor.
[0131]
When the semiconductor for a photoelectric conversion material of the present invention is in the form of particles, the semiconductor for a photoelectric conversion material is preferably applied or sprayed on a conductive support to produce a semiconductor electrode. Further, when the semiconductor for a photoelectric conversion material of the present invention is in the form of a film and is not held on a conductive support, the semiconductor for a photoelectric conversion material is bonded to the conductive support to form a semiconductor electrode. It is preferable to make them.
[0132]
Hereinafter, the manufacturing process of the semiconductor for a photoelectric conversion material of the present invention will be specifically described.
<< Preparation of coating solution containing semiconductor fine powder >>
First, a coating solution containing fine semiconductor powder is prepared. This semiconductor fine powder preferably has a smaller primary particle diameter, and the primary particle diameter is preferably 1 nm to 5000 nm, and more preferably 2 nm to 50 nm. The coating liquid containing the semiconductor fine powder can be prepared by dispersing the semiconductor fine powder in a solvent. The semiconductor fine powder dispersed in the solvent is dispersed in the form of primary particles. The solvent is not particularly limited as long as it can disperse the semiconductor fine powder.
[0133]
The solvent includes water, an organic solvent, and a mixture of water and an organic solvent. Examples of the organic solvent include alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone, acetone and acetylacetone, and hydrocarbons such as hexane and cyclohexane. If necessary, a surfactant or a viscosity modifier (polyhydric alcohol such as polyethylene glycol) can be added to the coating solution. The range of the concentration of the semiconductor fine powder in the solvent is preferably from 0.1% by mass to 70% by mass, more preferably from 0.1% by mass to 30% by mass.
[0134]
<< Application of coating solution containing semiconductor fine powder and baking treatment of formed semiconductor layer >>
The semiconductor fine powder-containing coating solution obtained as described above is applied or sprayed on a conductive support, dried and the like, and then fired in air or an inert gas to form a coating on the conductive support. Then, a semiconductor layer (semiconductor film) is formed.
[0135]
The coating obtained by applying and drying the coating solution on the conductive support is composed of an aggregate of semiconductor fine particles, and the particle size of the fine particles corresponds to the primary particle size of the semiconductor fine powder used. is there.
[0136]
The semiconductor fine particle aggregate film thus formed on the substrate such as the conductive support has a low bonding strength with the conductive support and a low bonding strength between the fine particles, and a low mechanical strength. This is preferably performed because the semiconductor fine particle aggregate film is baked to increase the mechanical strength and become a baked product film firmly fixed to the substrate.
[0137]
In the present invention, the fired product film may have any structure, but is preferably a porous structure film (also referred to as a porous layer having voids).
[0138]
Here, the porosity of the semiconductor thin film according to the present invention is preferably 10% by volume or less, more preferably 8% by volume or less, and particularly preferably 0.01% to 5% by volume or less. The porosity of the semiconductor thin film means a porosity having a penetrating property in the thickness direction of the dielectric, and can be measured using a commercially available device such as a mercury porosimeter (Shimadzu Poreizer 9220).
[0139]
The thickness of the semiconductor layer, which has become a fired product film having a porous structure, is preferably at least 10 nm or more, more preferably 100 nm to 10000 nm.
[0140]
At the time of the baking treatment, the baking temperature is preferably lower than 1000 ° C., more preferably 200 ° C. to 800 ° C., from the viewpoint of appropriately adjusting the actual surface area of the baking product film and obtaining a baking product film having the above porosity. And particularly preferably in the range of 300 ° C to 800 ° C.
[0141]
The ratio of the actual surface area to the apparent surface area can be controlled by the particle size and specific surface area of the semiconductor fine particles, the firing temperature, and the like. After the heat treatment, for example, chemical plating using an aqueous solution of titanium tetrachloride or trichloride for the purpose of increasing the surface area of the semiconductor particles, increasing the purity in the vicinity of the semiconductor particles, and increasing the efficiency of electron injection from the dye to the semiconductor particles. Electrochemical plating using an aqueous titanium solution may be performed.
[0142]
《Semiconductor sensitization》
As described above, the semiconductor sensitization treatment is performed by dissolving the dye in an appropriate solvent, and immersing the substrate on which the fired product film of the semiconductor is formed in the solution. In that case, the substrate on which the semiconductor layer (also referred to as a semiconductor film) on which the fired product film is formed is subjected to a reduced pressure treatment or a heat treatment in advance to remove bubbles in the film, and the general formula (1) or ( It is preferable to allow any one of the dyes in 2) to penetrate deep inside the semiconductor layer (semiconductor film), and it is particularly preferable when the semiconductor layer (semiconductor film) is a porous structure film.
[0143]
"solvent"
The solvent used for dissolving any one of the dyes of the general formula (1) or (2) is capable of dissolving the dye and dissolving the semiconductor or reacting with the semiconductor. There is no particular limitation as long as it is not present, but in order to prevent moisture and gas dissolved in the solvent from entering the semiconductor film and hindering sensitization treatment such as adsorption of the dye, degassing and distillation are performed in advance. It is preferable to purify it.
[0144]
In dissolving the dye, a solvent preferably used is an alcohol solvent such as methanol, ethanol, or n-propanol; a ketone solvent such as acetone or methyl ethyl ketone; an ether solvent such as diethyl ether, diisopropyl ether, tetrahydrofuran, or 1,4-dioxane. Solvents are halogenated hydrocarbon solvents such as methylene chloride and 1,1,2-trichloroethane, and particularly preferred are methanol, ethanol, acetone, methyl ethyl ketone, tetrahydrofuran and methylene chloride.
[0145]
《Temperature and time of sensitization treatment》
The time for immersing the substrate on which the film obtained by firing the semiconductor is formed in a solution containing one of the compounds represented by the general formulas (1) and (2) is such that the compound penetrates deeply into the semiconductor layer (semiconductor film). From the viewpoint of sufficiently advancing the adsorption and the like, sufficiently sensitizing the semiconductor, and suppressing the decomposition products generated by the decomposition of the compound in the solution or the like to hinder the adsorption of the compound. Under the conditions, it is preferably 3 hours to 48 hours, more preferably 4 hours to 24 hours. This effect is particularly remarkable when the semiconductor film has a porous structure. However, the immersion time is a value under the condition of 25 ° C., and is not limited to the above when the temperature condition is changed.
[0146]
Upon immersion, the solution containing any one of the dyes of the general formula (1) or (2) may be heated to a temperature at which it does not boil unless the dye is decomposed. The preferred temperature range is from 10 ° C to 100 ° C, more preferably from 25 ° C to 80 ° C, but not limited to the case where the solvent boils within the aforementioned temperature range as described above.
[0147]
《Photoelectric conversion element》
The photoelectric conversion element of the present invention will be described with reference to FIG.
[0148]
FIG. 1 is a partial sectional view showing an example of the structure of the photoelectric conversion element of the present invention.
1 denotes a conductive support, 2 denotes a photosensitive layer, 3 denotes a charge transfer layer, and 4 denotes a counter electrode. The conductive support 1 and the photosensitive layer 2 are also referred to as a semiconductor electrode.
[0149]
Here, the photosensitive layer 2 is a layer containing the semiconductor for a photoelectric conversion material of the present invention, and the charge transfer layer 3 usually contains a redox electrolyte and is in contact with the conductive support 1, the photosensitive layer 2, and the counter electrode 4. Used in the form of
[0150]
<< Method of manufacturing photoelectric conversion element >>
A method for manufacturing a photoelectric conversion element will be described with reference to FIG.
[0151]
In the photoelectric conversion element of the present invention, the semiconductor thin film is formed on the conductive support 1 as shown in FIG. 1 as described above, and then expressed by the general formula (1) or (2) according to the present invention. It is manufactured through a process of adsorbing any one of the dyes.
[0152]
Further, by increasing the surface area of the semiconductor thin film or removing impurities or the like on the surface of the semiconductor thin film, the purity of the semiconductor is increased, and the semiconductor is converted from any one of the dyes represented by the general formula (1) or (2). In order to increase the efficiency of electron injection into the substrate, for example, chemical plating using an aqueous solution of titanium tetrachloride or electrochemical plating using an aqueous solution of titanium trichloride may be performed.
[0153]
The semiconductor film formed on the conductive support 1 adsorbs any one of the dyes represented by the above general formula (1) or (2), sensitizes the semiconductor film, and To form As described above, the sensitization treatment is performed by dissolving the compound in an appropriate solvent and immersing the semiconductor film formed on the conductive support 1 in the solution. In this case, the semiconductor film is subjected to a vacuum treatment or a heat treatment in advance to remove bubbles in the film, and any one of the dyes represented by the general formula (1) or (2) is applied to the semiconductor film. It is preferable to be able to enter deep inside.
[0154]
When adsorbing any one of the dyes represented by the general formula (1) or (2) on the semiconductor according to the present invention, the dye may be used alone or in combination. Further, conventionally known sensitizing dye compounds (for example, U.S. Pat. Nos. 4,684,537, 4,927,721, 5,084,365, 5,350,644, and 5,463,057, 5,525,440, JP-A-7-249790, and JP-A-2000-150007).
[0155]
In particular, when the semiconductor is used for a solar cell, it is preferable to use a mixture of two or more dyes so that the wavelength range of photoelectric conversion is widened and sunlight can be used as effectively as possible.
[0156]
The semiconductor for a photoelectric conversion material sensitized by using a plurality of any one kind of the dyes represented by the general formula (1) or (2) described above is a solution prepared by mixing the aforementioned compounds to be used in combination. Alternatively, it may be prepared by preparing a solution for each compound and immersing it in each solution in order.
[0157]
When preparing separate solutions for each compound and immersing them in each solution in order, the effect of the present invention can be obtained in any order in which the dye or the conventionally known sensitizing dye is adsorbed on the semiconductor. Can be obtained.
[0158]
In the adsorption treatment, a solution in which the compound is dissolved may be used at room temperature, or the solution may be heated to a temperature within a range that does not affect the compound. Further, it is preferable to remove the dye that has not been adsorbed during the adsorption treatment by washing with a solvent or the like.
[0159]
After the dye is adsorbed on the semiconductor film formed on the conductive support 1 to form the photosensitive layer 2, the counter electrode 4 is disposed so as to face the photosensitive layer 2. Further, a redox electrolyte, which is a charge transfer layer, is injected between the semiconductor electrode and the counter electrode 4 to form a photoelectric conversion element.
[0160]
《Solar cell》
The solar cell of the present invention will be described.
[0161]
As shown in FIG. 1, the solar cell of the present invention, as an embodiment of the photoelectric conversion element of the present invention, has an optimal design and circuit design for sunlight, and is optimal when solar light is used as a light source. It has a structure in which photoelectric conversion is performed. That is, the structure is such that the semiconductor for the photoelectric conversion material can be irradiated with sunlight. When configuring the solar cell of the present invention, it is preferable that the semiconductor electrode, the charge transfer layer, and the counter electrode are housed in a case and sealed, or the whole is sealed with resin.
[0162]
When the solar cell of the present invention is irradiated with sunlight or an electromagnetic wave equivalent to sunlight, the compound of the present invention adsorbed on the semiconductor for a photoelectric conversion material absorbs the irradiated light or electromagnetic wave and is excited. The electrons generated by the excitation move to the semiconductor, and then move to the counter electrode 4 via the conductive support 1 to reduce the redox electrolyte of the charge transfer layer 3. On the other hand, the dye compound of the present invention in which electrons have been transferred to the semiconductor is in an oxidized form, but is reduced by the supply of electrons from the counter electrode 4 through the redox electrolyte of the charge transfer layer 3 to be reduced. At the same time, the redox electrolyte of the charge transfer layer 3 is oxidized and returns to a state where it can be reduced again by the electrons supplied from the counter electrode 4. In this manner, electrons flow and a solar cell using the photoelectric conversion element of the present invention can be formed.
[0163]
《Conductive support》
The conductive support used in the photoelectric conversion element of the present invention or the solar cell of the present invention is provided with a conductive material such as a metal plate or a non-conductive material such as a glass plate or a plastic film. Can be used. Examples of the material used for the conductive support include metal (for example, platinum, gold, silver, copper, aluminum, rhodium, indium) or conductive metal oxide (for example, indium-tin composite oxide, tin oxide doped with fluorine). ) And carbon. The thickness of the conductive support is not particularly limited, but is preferably 0.3 mm to 5 mm.
[0164]
The conductive support is preferably substantially transparent, and substantially transparent means that the light transmittance is 10% or more, more preferably 50% or more, and 80% or more. % Is most preferable. In order to obtain a transparent conductive support, it is preferable to provide a conductive layer made of a conductive metal oxide on the surface of a glass plate or a plastic film. When the conductive support 1 is transparent, it is preferable that light be incident from the support side.
[0165]
The conductive support has a surface resistance of 50Ω / cm.²Preferably 10 Ω / cm²It is more preferred that:
[0166]
《Charge transfer layer》
The charge transfer layer used in the present invention will be described.
[0167]
A redox electrolyte is preferably used for the charge transfer layer. Here, as the redox electrolyte, I⁻/ I₃ ⁻System, Br⁻/ Br₃ ⁻System, quinone / hydroquinone system and the like. Such a redox electrolyte can be obtained by a conventionally known method.⁻/ I₃ ⁻The system electrolyte can be obtained by mixing iodine with an ammonium salt of iodine. The charge transfer layer is composed of a dispersion of these redox electrolytes, and these dispersions are dispersed in a liquid electrolyte in the case of a solution, and in a solid polymer electrolyte or a gel-like substance when dispersed in a polymer that is solid at ordinary temperature. When done, it is called a gel electrolyte. When a liquid electrolyte is used as the charge transfer layer, an electrochemically inactive solvent is used as the solvent, for example, acetonitrile, propylene carbonate, ethylene carbonate, or the like. Examples of the solid polymer electrolyte include electrolytes described in JP-A-2001-160427, and examples of the gel electrolyte include electrolytes described in “Surface Science”, Vol. 21, No. 5, pages 288 to 293.
[0168]
《Counter electrode》
The counter electrode used in the present invention will be described.
[0169]
The counter electrode may have any conductivity, and any conductive material may be used.₃ ⁻It is preferable to use one having a catalytic ability to cause oxidation of ions or the like or reduction reaction of other redox ions at a sufficient speed. Examples of such a material include a platinum electrode, a material obtained by performing platinum plating or platinum deposition on the surface of a conductive material, rhodium metal, ruthenium metal, ruthenium oxide, and carbon.
[0170]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[0171]
Example 1
<< Preparation of photoelectric conversion element 1 >>
As described below, a photoelectric conversion element as shown in FIG. 1 was produced.
[0172]
62.5 ml of titanium tetraisopropoxide (first grade, manufactured by Wako Pure Chemical Industries, Ltd.) was dropped into 375 ml of pure water at room temperature for 10 minutes with vigorous stirring (a white precipitate was formed), and then 70% aqueous nitric acid was added. After adding 2.65 ml and heating the reaction system to 80 ° C., stirring was continued for 8 hours. Further, the reaction mixture was concentrated under reduced pressure until the volume of the reaction mixture became about 200 ml. Then, 125 ml of pure water and 140 g of titanium oxide powder (Super Titania F-6 manufactured by Showa Titanium Co.) were added, and a titanium oxide suspension (about 800 ml) was added. ) Was prepared. The titanium oxide suspension is applied on a transparent conductive glass plate (conductive support 1) coated with fluorine-doped tin oxide, dried naturally, and baked at 300 ° C. for 60 minutes. A film-like titanium oxide was formed.
[0173]
Then, a solution in which 5 g of Exemplified Compound I-1 was dissolved in 200 ml of a methanol solution was prepared, and the above-mentioned film-form titanium oxide (semiconductor layer for a photoelectric conversion material) was immersed together with the support, and 1 g of trifluoroacetic acid was further added thereto. Ultrasonic irradiation was performed for hours. After the reaction, the film-like titanium oxide (semiconductor layer for a photoelectric conversion material) was washed with chloroform and dried under vacuum to prepare a photosensitive layer 2.
[0174]
As the counter electrode 4, a transparent conductive glass plate coated with fluorine-doped tin oxide and further supporting platinum thereon is used, and the conductive support 1 having the film-like titanium oxide photosensitive layer formed thereon and the counter electrode And tetrapropylammonium iodide and iodine in a mixed solvent of acetonitrile / ethylene carbonate having a volume ratio of 1: 4 between 0.44 mol / l and 0.06 mol / l. Thus, a redox electrolyte dissolved as described above was inserted as the charge transfer layer 3 to produce the photoelectric conversion element 1.
[0175]
<< Preparation of photoelectric conversion elements 2-23 >>
Photoelectric conversion elements 2 to 23 were obtained in the same manner as in the production of photoelectric conversion element 1, except that Exemplified Compound I-1 was changed to the compound shown in Table 1.
[0176]
<< Preparation of Photoelectric Conversion Element R1 >>: Comparative Example
A photoelectric conversion element R1 was obtained in the same manner as in the preparation of the photoelectric conversion element 1, except that the example compound I-1 was changed to the comparative compound R1.
[0177]
Embedded image

[0178]
<< Production of solar cells SC-1 to SC-23 >>
After enclosing the side surface of the photoelectric conversion element 1 with resin, lead wires were attached, and solar cells SC-1 to SC-23 of the present invention were manufactured in three lots each.
[0179]
<< Production of solar cell SC-R1 >>
Three lots of solar cells SC-R1 were produced in the same manner as in the production of solar cell SC-1 except that comparative photoelectric conversion element R1 was used.
[0180]
<< Evaluation of photoelectric conversion characteristics of solar cells >>
The solar cells SC-1 to SC-23 and the solar cell SC-R1 obtained above were each 100 mW / m by a solar simulator (manufactured by JASCO (JASCO Corporation, low energy spectral sensitivity measuring apparatus CEP-25)).²Current density Jsc (mA / cm²) And the open-circuit voltage value Voc (V) were measured and are shown in Table 1. The numerical values were average values of the measurement results of three solar cells having the same configuration and manufacturing method.
[0181]
[Table 1]

[0182]
Table 1 shows that the solar cell of the present invention exhibits higher photoelectric conversion characteristics than the comparison, and it is effective to use any one of the compounds represented by the general formula (1). In addition, the solar cells SC-1 to SC-23 of the present invention have a power of 100 mW / m by a solar simulator.²No decrease in photoelectric conversion efficiency was observed even after 100 hours of light irradiation, and it was clear that the composition was excellent in stability.
[0183]
Example 2
<< Preparation of photoelectric conversion elements 101-121 and R2 >>
In the production of the photoelectric conversion element 1 described in Example 1, photoelectric conversion elements 101 to 121 and R2 were respectively produced in the same manner except that the exemplified compound I-1 was changed to the compound shown in Table 2.
[0184]
<< Production of solar cells SC-101 to SC-121 and SC-R2 >>
In the production of the solar cell SC-1 described in Example 1, the solar cells SC-101 to SC-121 and SC-R2 were manufactured in the same manner except that the photoelectric conversion element 1 was the photoelectric conversion element described in Table 2. Were manufactured in three lots.
[0185]
<< Evaluation of photoelectric conversion characteristics of solar cells >>
The solar cells SC-101 to SC-121 and the solar cell SC-R2 obtained above were each applied with a solar simulator (manufactured by JASCO (JASCO), low-energy spectral sensitivity measuring apparatus CEP-25) to 100 mW / m²Current density Jsc (mA / cm²) And the open-circuit voltage value Voc (V) were measured and are shown in Table 2. The numerical values were the average values of the measurement results for three solar cells having the same configuration and manufacturing method.
[0186]
[Table 2]

[0187]
Embedded image

[0188]
Table 2 shows that the solar cell of the present invention exhibits higher photoelectric conversion characteristics than the comparison, and it is effective to use any one of the compounds represented by the general formula (2). Moreover, the solar cells SC-101 to SC-121 of the present invention have a power of 100 mW / m by a solar simulator.²No decrease in photoelectric conversion efficiency was observed even after 100 hours of light irradiation, and it was clear that the composition was excellent in stability.
[0189]
【The invention's effect】
According to the present invention, a semiconductor for a photoelectric conversion material, a photoelectric conversion element, and a solar cell exhibiting high photoelectric conversion efficiency and excellent stability can be provided.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating an example of a structure of a photoelectric conversion element of the present invention.
[Explanation of symbols]
1 conductive support
2 Photosensitive layer
3 Charge transfer layer
4 Counter electrode

Claims (8)

A semiconductor for a photoelectric conversion material, comprising a dye represented by the general formula (1).

(Wherein, Z and Z ′ each independently represent an atomic group necessary for forming a 5- to 6-membered ring together with a carbon atom, and each ring has at least one carboxyl group or a carboxyl group. Having a substituent, B ₁ and B ₂ each independently represent —C (R ₁ ) R ₂ — or —NR ₃ —, and R _{1 to} R ₃ represent a hydrogen atom or a substituent.) A semiconductor for a photoelectric conversion material, comprising a dye represented by the general formula (2).

(Wherein, Z and Z ′ each independently represent an atomic group necessary for forming a 5- to 6-membered ring together with a carbon atom, and each ring has at least one carboxyl group or a carboxyl group. Having a substituent, B ₁ and B ₂ each independently represent —C (R ₁ ) R ₂ — or —NR ₃ —, and R _{1 to} R ₃ represent a hydrogen atom or a substituent.) 3. The photoelectric conversion device according to claim 1, wherein the ring formed by including the atomic group Z or Z ′ of the dye represented by the general formula (1) or (2) is a 5-membered ring. 4. Semiconductor for materials. The ring structure formed including the atomic group Z or Z 'of the dye represented by the general formula (1) or (2) is represented by the general formulas a to d. The semiconductor for a photoelectric conversion material according to 1.

(Wherein R ₄ and R ₅ represent a hydrogen atom or a substituent, Z ₂ represents an atomic group necessary for forming a 5- or 6-membered ring, and each ring has at least one of a carboxyl group or (In the general formulas a to d, * represents a binding site to a squarylium ring or a croconium ring.) The ring structure formed including Z or Z 'of the dye represented by the general formula (1) or (2) is represented by the general formulas (Cp-1), (Cp-2), (Cp-3), The semiconductor for a photoelectric conversion material according to claim 1, wherein the semiconductor is represented by (Cp-5), (Cp-13), (Cp-14), or (Cp-15).

(In the general formula (Cp-1), R ₆₁ represents an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an amino group, a carboxyl group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, an ureido group, or an alkoxy group. R ₆₂ represents an alkyl group, an aryl group or a heterocyclic group;
In the general formulas (Cp-2) and (Cp-3), R ₆₃ and R ₆₄ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino Group, amino group, alkylamino group, alkylthio group, arylthio group, alkoxyl group, aryloxy group, ureido group, alkoxycarbonylamino group, carbamoyl group, carboxyl group or alkoxycarbonyl group,
In Formula (Cp-5), R ₆₃ has the same meaning as R ₆₃ in Formulas (Cp-2) and (Cp-3), and R ₆₅ and R ₆₇ each represent a hydrogen atom, an alkyl group, Aryl group, heterocyclic group, acylamino group, alkylsulfonylamino group, arylsulfonylamino group, amino group, alkylthio group, arylthio group, alkoxyl group, aryloxy group, ureido group, alkoxycarbonylamino group, acyl group, carboxyl group, Represents an alkoxycarbonyl group or a carbamoyl group,
In the general formula (Cp-13), R ₈₅ and R ₈₆ each represent a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, an amino group, an alkylthio group, Represents an arylthio group, an alkoxyl group, an aryloxy group, a ureido group, an alkoxycarbonylamino group, an acyl group, a carboxyl group, an alkoxycarbonyl group or a carbamoyl group;
In formulas (Cp-14) and (Cp-15), R ₈₇ and R ₈₈ each represent a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, or a carboxyl group. , A cyano group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a nitro group; R ₈₉ represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group,
Further, a ring represented by the general formula (Cp-1), (Cp-2), (Cp-3), (Cp-5), (Cp-13), (Cp-14) or (Cp-15). Having at least one carboxyl group or a substituent having a carboxyl group in the structure, and having the general formula (Cp-1), (Cp-2), (Cp-3), (Cp-5), or (Cp-13) , (Cp-14) or (Cp-15), * represents a binding site to a squarylium ring or a croconium ring. ) The semiconductor for a photoelectric conversion material according to claim 1, wherein the semiconductor for a photoelectric conversion material is a metal oxide or a metal sulfide semiconductor. A photoelectric conversion element, wherein a photosensitive layer containing the semiconductor for a photoelectric conversion material according to any one of claims 1 to 6 is provided on a conductive support. A solar cell comprising the photoelectric conversion element according to claim 7, a charge transfer layer, and a counter electrode.

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