JP2004319202A - 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 rate and high stability, and to provide 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, and in the formula, A<SB>1</SB>to A<SB>4</SB>represents a hydrogen atom or a substituent group, n is 0 or 1, R<SB>1</SB>to R<SB>3</SB>represents a hydrogen atom or a substituent group, and X represents an oxygen atom, a sulfur atom, NR<SB>4</SB>, or CR<SB>5</SB>R<SB>6</SB>(R<SB>4</SB>to R<SB>6</SB>represents a hydrogen atom or a substituent group.). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５１】
以下に、上記一般式（Ｃｐ−１）〜（Ｃｐ−１８）で表される化合物について詳しく説明する。
【００５２】
《一般式（Ｃｐ−１）、一般式（Ｃｐ−２）》
一般式（Ｃｐ−１）、（Ｃｐ−２）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。
【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−３）、一般式（Ｃｐ−４）》
一般式（Ｃｐ−３）、（Ｃｐ−４）において、Ｒ_６３及びＲ_６４は、前記一般式（Ｃｐ−１）、（Ｃｐ−２）に記載のＲ_６３及びＲ_６４と同義である。
【００５６】
Ｒ_６５及び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】
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_６４、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。
【００５８】
《一般式（Ｃｐ−５）》
一般式（Ｃｐ−５）において、Ｒ_６８及び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。
【００５９】
式中、Ｒ_６８、Ｒ_６９で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、カルボキシル基等が挙げられる。
【００６０】
《一般式（Ｃｐ−６）〜（Ｃｐ−１０）》
一般式（Ｃｐ−６）〜（Ｃｐ−１０）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。
【００６１】
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。
【００６２】
《一般式（Ｃｐ−１１）〜（Ｃｐ−１８）》
一般式（Ｃｐ−１１）〜（Ｃｐ−１８）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。
【００６３】
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、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。
【００６４】
また、Ｑは好ましくは下記一般式ａ〜ｄで表されることが好ましい。
【００６５】
【化１１】

【００６６】
一般式ａ〜ｄにおいて、Ｒ_４′及びＲ_５′は各々水素原子または置換基を表し、Ｚ２は５または６員環を形成するために必要な原子団を表し、置換基を有していても良く、置換基で結合し縮環を形成しても良く、＊でＱ以外の部分と結合する。また、少なくとも１つはカルボキシル基を有している。Ｒ_４′及びＲ_５′の置換基は前述した置換基と同義である。
【００６７】
Ｚ２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。
【００６８】
【化１２】

【００６９】
一般式ａ−１〜ａ−３、ａ−６〜ａ−９は前述した一般式（Ｃｐ−１）〜（Ｃｐ−３）、（Ｃｐ−１５）〜（Ｃｐ−１８）と同一の化合物であり、一般式ａ−４及びａ−５におけるＲ_４′、Ｒ_６′、Ｒ_７′はそれらと同義である。
【００７０】
Ｒ_４′〜Ｒ_７′は各々水素原子または置換基を表し、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。
【００７１】
一般式ｂ〜ｄにおいても同様の構造を持つ化合物が挙げられる。例えば一般式ｂは一般式（Ｃｐ−８）、（Ｃｐ−１０）、（Ｃｐ−１２）及び（Ｃｐ−１４）が、一般式ｃは一般式（Ｃｐ−６）、（Ｃｐ−７）、（Ｃｐ−９）、（Ｃｐ−１１）及び（Ｃｐ−１３）が、例えば一般式ｄは一般式（Ｃｐ−４）及び（Ｃｐ−５）などが挙げられるがこれらに限定されることはない。
【００７２】
次に、一般式（４）について説明する。
一般式（４）において、Ａ_１〜Ａ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、ｎは０〜２の整数を表し、Ｒ_２、Ｒ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、Ｘは酸素原子、硫黄原子、ＮＲ_４またはＣＲ_５Ｒ_６を表し、Ｙは窒素原子またはＣＲ_７を表し、Ｒ_４〜Ｒ_７は各々水素原子または置換基を表し、Ｑは前記一般式（５）または（６）で表される。
【００７３】
ここで、一般式（５）及び（６）は、各々一般式（１）における一般式（２）及び（３）と同義である。
【００７４】
一般式（４）においてＡ_１〜Ａ_３、Ｒ_２〜Ｒ_７における置換基としては一般式（１）で説明した基が挙げられるが、Ａ_１〜Ａ_３として好ましい置換基としては水素原子、アルキル基、シクロアルキル基、ハロゲン原子、カルボキシル基、アルコキシカルボニル基などが挙げられる。更に好ましくは水素原子、アルキル基である。
【００７５】
Ｒ_２及びＲ_３として好ましくは水素原子、アルキル基、アリール基、アミノ基、アルコキシ基及び複素環基である。
【００７６】
Ｒ_２とＲ_３は互いに結合して環構造を形成しても良い。形成される環構造としては脂肪族環、芳香族環のいずれでも良く、炭化水素環であっても複素環であっても良い。Ｒ_２とＲ_３が結合して形成された環も、上記に示した置換基によって置換されていても良いし、更に別の環構造と縮合していても良い。
【００７７】
好ましくはＲ_２とＲ_３が環構造を形成することが好ましく、更に好ましくは芳香族環を形成することが好ましい。
【００７８】
Ｒ_４〜Ｒ_７として好ましくは水素原子、アルキル基、アリール基、アリール基、複素環基が挙げられるが更に好ましくは水素原子、アルキル基である。
【００７９】
Ｘとして好ましくは、硫黄原子、ＮＲ_４またはＣＲ_５Ｒ_６である。
次に、一般式（７）について説明する。
【００８０】
一般式（７）においてＡ_１〜Ａ_４は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、ｎは０または１を表し、Ｒ_１〜Ｒ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、Ｘは酸素原子、硫黄原子、ＮＲ_４またはＣＲ_５Ｒ_６を表し、Ｒ_４〜Ｒ_６、Ｒ_８及びＲ_９は各々水素原子または置換基を表し、これらの好ましい置換基についても一般式（１）と同義である。
【００８１】
一般式（７）において、Ｒ_８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、アニリノ基、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_９はアルキル基、アリール基または複素環基を表す。
【００８２】
ここで、前記Ｒ_８、Ｒ_９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。
【００８３】
一般式（７）において、Ｒ_８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、アニリノ基、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。
【００８４】
一般式（７）において、Ｒ_９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、複素環基が挙げられるが、更に好ましくはアルキル基、アリール基である。
【００８５】
次に、一般式（８）について説明する。
一般式（８）においてＡ_１〜Ａ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、ｎは０〜２の整数を表し、Ｒ_２、Ｒ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、Ｘは酸素原子、硫黄原子、ＮＲ_４またはＣＲ_５Ｒ_６を表し、Ｙは窒素原子またはＣＲ_７を表し、Ｒ_４〜Ｒ_９は各々水素原子または置換基を表し、これらの好ましい置換基についても一般式（４）と同義である。Ｒ_８及びＲ_９の好ましい置換基は一般式（７）の場合と同じである。
【００８６】
次に、一般式（９）について説明する。
一般式（９）において、Ａ_１〜Ａ_４は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、ｎは０または１を表し、Ｒ_１〜Ｒ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、Ｘは酸素原子、硫黄原子、ＮＲ_４またはＣＲ_５Ｒ_６を表し、Ｒ_４〜Ｒ_６は各々水素原子または置換基を表し、これらの好ましい置換基についても一般式（１）と同義である。
【００８７】
Ｂ_１は窒素原子またはＣＲ_７を表し、Ｒ_７〜Ｒ_９は各々水素原子または置換基を表し、置換基は前述の通りである。
【００８８】
一般式（９）において、Ｒ_７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、複素環基、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、アルキル基、アリール基、アシルアミノ基、アルコキシカルボニル基、カルボキシル基である。
【００８９】
一般式（９）において、Ｒ_８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、複素環基、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、アルキル基、アリール基、複素環基、カルボキシル基である。
【００９０】
一般式（９）において、Ｒ_９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、複素環基、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基、カルボキシル基等が挙げられ、更に好ましくは、アルキル基、アリール基、アシルアミノ基、アルコキシカルボニル基、カルボキシル基である。
【００９１】
次に、一般式（１０）について説明する。
一般式（１０）において、Ａ_１〜Ａ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、ｎは０〜２の整数を表し、Ｒ_２、Ｒ_３は各々水素原子または置換基を表し、各々が結合し環を形成しても良く、Ｘは酸素原子、硫黄原子、ＮＲ_４またはＣＲ_５Ｒ_６を表し、Ｒ_４〜Ｒ_６は各々水素原子または置換基を表し、これらの好ましい置換基についても一般式（４）と同義である。
【００９２】
Ｙ及びＢ_１は窒素原子またはＣＲ_７を表し、Ｒ_７〜Ｒ_９は水素原子または置換基を表し、置換基は前述の通りである。Ｒ_７〜Ｒ_９の好ましい置換基は一般式（９）と同義である。
【００９３】
本発明に係る、前記一般式（１）、（４）、及び（７）〜（１０）で各々表される化合物において、特に好ましく用いられるのは、前記一般式（１）、（７）または前記一般式（９）で表される化合物であり、中でも、Ｑとして、前記一般式（Ｃｐ−１）または（Ｃｐ−２）を有するピラゾロアゾール化合物、前記一般式（Ｃｐ−３）を有するピラゾロイミダゾール化合物、前記一般式（Ｃｐ−４）を有するイミダゾピラゾール化合物、前記一般式（Ｃｐ−６）を有するピロロトリアゾール化合物や、前記一般式（Ｃｐ−１５）を有するピラゾロピリミジン−７−オン化合物が好ましい。
【００９４】
以下に、本発明に係る前記一般式（１）、（４）、及び（７）〜（１０）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。
【００９５】
まず、前記一般式（１）、（４）における一般式（２）、（３）、（５）及び（６）の具体例を示すが本発明はこれらに限定されない。
【００９６】
【化１３】

【００９７】
【化１４】

【００９８】
【化１５】

【００９９】
【化１６】

【０１００】
【化１７】

【０１０１】
【化１８】

【０１０２】
次に上記一般式（１）及び（４）の具体例を示すが本発明はこれらに限定されないことは言うまでもない。
【０１０３】
【化１９】

【０１０４】
【化２０】

【０１０５】
【化２１】

【０１０６】
【化２２】

【０１０７】
【化２３】

【０１０８】
【化２４】

【０１０９】
【化２５】

【０１１０】
【化２６】

【０１１１】
次に一般式（７）〜（１０）の具体例を示すが本発明はこれらに限定されないことは言うまでもない。
【０１１２】
【化２７】

【０１１３】
【化２８】

【０１１４】
【化２９】

【０１１５】
【化３０】

【０１１６】
【化３１】

【０１１７】
【化３２】

【０１１８】
【化３３】

【０１１９】
【化３４】

【０１２０】
本発明に係る前記一般式（１）、（４）、及び（７）〜（１０）で表される化合物は、例えば、特開平１０−６０２９６号公報、特開２０００−１９１９３４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。
【０１２１】
以下に具体的に合成法の一例を示すが、その他の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。
【０１２２】
合成例１
例示化合物Ｉ−２７の合成
１）合成ルート
【０１２３】
【化３５】

【０１２４】
２）例示化合物Ｉ−２７の合成
中間体１：２．００ｇにエタノール：６０ｍｌ、酢酸カリウム：０．６６ｇ及び中間体２：３．２４ｇを加え３時間５０℃で加熱反応させる。その後、１時間加熱還流反応させ、反応終了後冷却する。析出する結晶をろ過し、酢酸エチルで洗浄し、例示化合物Ｉ−２７：２．９４ｇを得た。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６３０ｎｍであった。
【０１２５】
合成例２
例示化合物ＩＩ−７の合成
１）合成ルート
【０１２６】
【化３６】

【０１２７】
２）例示化合物ＩＩ−７の合成
中間体３：２．０４ｇにトルエン：２５ｍｌ、モルホリン：０．７４ｇ及び中間体４：１．５１ｇを加え３時間加熱還流反応させる。反応終了後室温まで冷却する。析出する結晶をろ過し、酢酸エチルで洗浄し、例示化合物ＩＩ−７：２．８２ｇを得た。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。
【０１２８】
合成例３
例示化合物ＩＩＩ−１の合成
１）合成ルート
【０１２９】
【化３７】

【０１３０】
２）例示化合物ＩＩＩ−１の合成
中間体５：２．３３ｇにエタノール：１２０ｍｌ、酢酸カリウム：１．３２ｇ及び中間体６：５．９０ｇを加え３時間６０℃で加熱反応させる。その後、１時間加熱還流反応させ、反応終了後冷却する。析出する結晶をろ過し、酢酸エチルで洗浄し、例示化合物ＩＩＩ−１：４．７４ｇを得た。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。
【０１３１】
合成例４
例示化合物ＩＶ−４の合成
１）合成ルート
【０１３２】
【化３８】

【０１３３】
２）例示化合物ＩＶ−４の合成
中間体７：２．２６ｇにエタノール：１２０ｍｌ、酢酸カリウム：１．３２ｇ及び中間体８：５．６６ｇを加え３時間６０℃で加熱反応させる。その後、１時間加熱還流反応させ、反応終了後冷却する。析出する結晶をろ過し、酢酸エチルで洗浄し、例示化合物ＩＶ−４：４．１８ｇを得た。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。
【０１３４】
《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）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物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、該化合物を含むとは、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が挙げられる。
【０１３５】
また、半導体層（半導体でも良い）１ｍ^２あたりの前記一般式（１）、（４）及び（７）〜（１０）で表される、各々の化合物の総含有量は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。
【０１３６】
本発明に係る前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物を用いて増感処理を行う場合、前記化合物を単独で用いても良いし、複数を併用することも、本発明に係る前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物と他の化合物（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。
【０１３７】
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。
【０１３８】
半導体に、前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物を含ませるには、前記化合物を適切な溶媒（エタノールなど）に溶解し、その溶液中に良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。
【０１３９】
前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物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良いし、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作製しても良い。
【０１４０】
吸着処理は半導体が粒子状の時に行っても良いし、支持体上に膜を形成した後に行っても良い。吸着処理に用いる化合物を溶解した溶液は、それを常温で用いても良いし、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良い。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良い。また、半導体微粒子と本発明の前記化合物とを同時に塗布することにより、前記化合物の吸着を実施しても良い。また、未吸着の化合物は洗浄によって除去することができる。
【０１４１】
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）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物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。
【０１４２】
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、前記化合物や増感色素化合物等の吸着処理（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。
【０１４３】
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良い。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。
【０１４４】
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。
【０１４５】
また、本発明に係る前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物と併用して用いることのできる色素としては、本発明に係る半導体を分光増感し得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。
【０１４６】
本発明に係る色素の中では、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。
【０１４７】
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９８９／５０３９３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。
【０１４８】
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号に記載の色素が好ましい色素としてあげられる。
【０１４９】
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。
【０１５０】
《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。
【０１５１】
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。
【０１５２】
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、上記の化合物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。
【０１５３】
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良い。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。
【０１５４】
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良く、特に制約されない。
【０１５５】
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。
【０１５６】
《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。
【０１５７】
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。
【０１５８】
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。
【０１５９】
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。
【０１６０】
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できる。
【０１６１】
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。
【０１６２】
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。
【０１６３】
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良い。
【０１６４】
《半導体の増感処理》
半導体の増感処理は、上記のように、色素を適切な溶媒に溶解し、その溶液に前記半導体を焼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）を焼成により形成させた基板を、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）、（４）及び（７）〜（１０）のいずれか１種の化合物が半導体層（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。
【０１６５】
《溶媒》
前記一般式（１）、（４）及び（７）〜（１０）のいずれか１種の化合物を溶解するのに用いる溶媒は、前記化合物を溶解することができ、かつ、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及び気体が半導体膜に進入して、前記化合物の吸着等の増感処理を妨げることを防ぐために、あらかじめ脱気及び蒸留精製しておくことが好ましい。
【０１６６】
前記化合物の溶解において、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。
【０１６７】
《増感処理の温度、時間》
半導体を焼成した基板を、前記一般式（１）、（４）及び（７）〜（１０）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、かつ、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。
【０１６８】
浸漬しておくにあたり前記一般式（１）、（４）及び（７）〜（１０）のいずれか１種の化合物を含む溶液は、前記化合物が分解しない限りにおいて、沸騰しない温度にまで加熱して用いても良い。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、前記の通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。
【０１６９】
《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。
【０１７０】
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。
【０１７１】
ここで、感光層２は本発明の光電変換材料用半導体を有する層であり、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。
【０１７２】
《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。
【０１７３】
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、上記記載のようにプラズマ処理装置を用いて半導体薄膜を形成した後に、本発明に係る前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物を吸着させるという工程を経て製造される。
【０１７４】
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）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物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良い。
【０１７５】
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）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物を吸着させ、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通り、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）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物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。
【０１７６】
本発明に係る半導体に、前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物を吸着させる際には、単独で用いても良いし、複数を併用しても良い。更に、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良い。
【０１７７】
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。
【０１７８】
上記記載の前記一般式（１）、（４）及び（７）〜（１０）で表されるいずれか１種の化合物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良いし、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。
【０１７９】
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。
【０１８０】
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良いし、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。
【０１８１】
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。更に、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。
【０１８２】
《太陽電池》
本発明の太陽電池について説明する。
【０１８３】
本発明の太陽電池は、図１に示すような、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時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得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。
【０１８４】
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得る状態に戻る。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。
【０１８５】
《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。
【０１８６】
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％以上であることが更に好ましく、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。透明な導電性支持体１を用いる場合、光は支持体側から入射させることが好ましい。
【０１８７】
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以下であることが更に好ましい。
【０１８８】
《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。
【０１８９】
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。
【０１９０】
《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。
【０１９１】
対向電極は、導電性を有するものであれば良く、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メッキ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。
【０１９２】
【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。
【０１９３】
実施例１
《光電変換素子１の作製》
下記に記載のようにして、図１に示すような光電変換素子を作製した。
【０１９４】
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。更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。
【０１９５】
次いで、メタノール溶液２００ｍｌ中に、例示化合物Ｉ−２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、更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（光電変換材料用半導体）を作製した。
【０１９６】
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、更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ヨウ素とを、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入れた電荷移動層３を作製して、光電変換素子１を作製した。
【０１９７】
《光電変換素子２〜２０の作製》：本発明
光電変換素子１の作製において、例示化合物Ｉ−２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２〜２０を得た。
【０１９８】
《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、表１に記載の比較化合物Ｒ１に変更した以外は同様にして、光電変換素子Ｒ１を得た。
【０１９９】
【化３９】

【０２００】
《太陽電池ＳＣ−１〜ＳＣ−２０の作製》：本発明
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−２０を各々３ロットずつ作製した。
【０２０１】
《太陽電池ＳＣ−Ｒ１の作製》：比較例
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ロットずつ作製した。
【０２０２】
《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−２０、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）及び開放電圧値Ｖｏｃ（Ｖ）を測定し表１に示した。示した値は、同じ構成及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。
【０２０３】
【表１】

【０２０４】
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）、（７）及び（９）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、本発明の太陽電池ＳＣ−１〜ＳＣ−２０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らかになった。
【０２０５】
実施例２
《光電変換素子１０１〜１２０、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−２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１０１〜１２０、Ｒ２を各々作製した。
【０２０６】
【化４０】

【０２０７】
《太陽電池ＳＣ−１０１〜ＳＣ−１２０：本発明、ＳＣ−Ｒ２：比較例の作製》
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−１２０、ＳＣ−Ｒ２を各々、３ロットずつ作製した。
【０２０８】
《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−１２０、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）及び開放電圧値Ｖｏｃ（Ｖ）を測定し表２に示した。示した値は、同じ構成及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。
【０２０９】
【表２】

【０２１０】
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（４）、（８）及び（１０）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、本発明の太陽電池ＳＣ−１０１〜ＳＣ−１２０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らかになった。
【０２１１】
【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 that can continuously extract light energy 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, for practical use to replace silicon solar cells, higher energy conversion efficiency, higher short-circuit current, open-circuit voltage, and form factor are required, and porous semiconductor electrodes are currently used. The reported substances 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 studied so far, the ruthenium complex dye is known to have relatively excellent properties, but the dye is expensive, and ruthenium, which is 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 these 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 the ruthenium complex dye, but well-known dyes include merocyanine dyes, xanthene dyes, coumarin dyes, acridine dyes, and phenylmethane dyes. Among them, there are many patents for merocyanine dyes. For example, the dye described in JP-A-11-167937 is an odd-number methine dye, which is characterized in that the molecule is cationic and has a counter salt. JP-A-11-214730 describes a substance having a methine number of 3 or more such as a trimethine dye. Japanese Unexamined Patent Publication (Kokai) No. 11-214731 discloses an even-number methine dye, but none of the dyes has satisfactory performance. Therefore, further development of a dye having high efficiency up to a long wavelength is desired. I have.
[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]
An object of the present invention is to provide a semiconductor for a photoelectric conversion material, a photoelectric conversion element, and a solar cell that exhibit 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.
[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 (4).
[0021]
3. A semiconductor for a photoelectric conversion material, comprising at least one dye represented by the general formula (7) or (8).
[0022]
4. A semiconductor for a photoelectric conversion material, comprising at least one dye represented by the general formula (9) or (10).
[0023]
5. 3. Q of the dye according to the above 1 or 2, wherein the general formula (Cp-1), (Cp-2), (Cp-3), (Cp-4), (Cp-6) and (Cp-15) A semiconductor for a photoelectric conversion material, which is represented by any one of the above.
[0024]
6. 6. The semiconductor for a photoelectric conversion material according to any one of 1 to 5, wherein the semiconductor is a metal oxide or metal sulfide semiconductor.
[0025]
7. 6. A photoelectric conversion element, wherein a photosensitive layer containing the semiconductor for a photoelectric conversion material according to any one of the above 1 to 5 is provided on a conductive support.
[0026]
8. A solar cell comprising the photoelectric conversion element, a charge transfer layer, and a counter electrode according to claim 7.
[0027]
Hereinafter, the present invention will be described in detail.
The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the general formulas (1), (4) and (7) to (10) described in claims 1 to 4 are respectively described. By the semiconductor for a photoelectric conversion material sensitized using a compound having a specific structure as represented, the effect according to the present invention, that is, a semiconductor for a photoelectric conversion material showing high photoelectric conversion efficiency and excellent stability. I succeeded in getting.
[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 semiconductors described above 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 in combination. Also, J.I. Chem. Soc. Chem. Commun. , 15 (1999). At this time, when a component other than the metal oxide or metal sulfide is added as the semiconductor, the mass ratio of the additional component to the metal oxide or metal sulfide semiconductor is preferably 30% or less.
[0032]
The object according to the present invention by subjecting the semiconductor for a photoelectric conversion material described above to a sensitization treatment with any one of the compounds represented by the general formulas (1), (4), and (7) to (10). The semiconductor for a photoelectric conversion material of the present invention, which exhibits high photoelectric conversion efficiency and excellent stability, which is one of the above, can be obtained.
[0033]
Hereinafter, the compounds represented by the general formulas (1) to (10) will be described.
<< Compound represented by the general formula (1) >>
The compound represented by the general formula (1) according to the present invention will be described.
[0034]
A₁~ A₄Each represents a hydrogen atom or a substituent, and each may combine to form a ring; n represents 0 or 1;₁~ R₃Each represents a hydrogen atom or a substituent, each of which may combine to form a ring, and X represents an oxygen atom, a sulfur atom, NR₄Or CR₅R₆And R₄~ R₆Each represents a hydrogen atom or a substituent, and Q is represented by the general formula (2) or (3).
[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.), alkoxyl group (eg, methoxy group, ethoxy group, propyloxy group, tert-butoxy group, pentyloxy group, hexyloxy) Group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl 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.), Cycloa Alkylthio 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, a methyloxycarbonyl group, an ethyloxycarbonyl group, a butyloxycarbonyl group, an octyloxycarbonyl group, a dodecyloxycarbonyl group, etc.), an aryloxycarbonyl group (eg, a phenyloxycarbonyl group) , Naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylamino Ruphonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc., ureido group (for example, methylureido group, ethylureido group, pentyl) Ureido group, cyclohexylureide group, octylureide group, dodecylureide group, phenylureide group, naphthylureide group, 2-pyridylaminoureide group, etc., acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group) , Cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcar An acyloxy 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 (for example, acetylamino group, benzoylamino group, formylamino group, pivaloylamino group, lauroylamino group, 3,4,5-tri-n-octyloxy) Phenylcarbonylamino group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexyl) A silcarbonylamino group, a 2-ethylhexylcarbonylamino group, an octylcarbonylamino group, a dodecylcarbonylamino group, a phenylcarbonylamino group, a naphthylcarbonylamino group, etc., a carbamoyl group (for example, an aminocarbonyl group, a methylaminocarbonyl group, a dimethylamino group) Carbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group Etc.), alkylsulfinyl group or arylsulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group) Phenyl, cyclohexylsulfinyl, 2-ethylhexylsulfinyl, dodecylsulfinyl, phenylsulfinyl, naphthylsulfinyl, 2-pyridylsulfinyl, etc., alkylsulfonyl or arylsulfonyl (eg, methylsulfonyl, ethylsulfonyl) 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 , Naphthylamino group, 2-pyridylamino group, etc.), silyloxy group (for example, trimethylsilyloxy group, tert-butyldimethylsilyloxy group, etc.), aminocarbonyloxy group (for example, N, N-dimethylcarbamoyloxy group, N, N -Diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group, etc., alkoxycarbonyloxy group (for example, methoxycarbonyloxy group, ethoxycarbonyl) Oxy group, tert-butoxycarbonyloxy group, n-octylcarbonyloxy group, etc.), aryloxycarbonyloxy group (for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexyl) Sadecyloxyphenoxycarbonyloxy group, etc., alkoxycarbonylamino group (for example, 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-chlorophenyl) Azo group, 5-ethylthio-1,3,4-thiadiazol-2-ylazo group, etc., heterocyclic azo group (for example, pyridylazo group, thiazolylazo group, oxazolylazo group, imidazolylazo group, furylazo group, pyrrolylazo group), imino Group (for example, N-succinimido-1-yl group, N-phthalimido-1-yl group, etc.), phosphino group (for example, dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group, etc.), phosphinyl group ( For example, phosphinyl group, dioctyloxyphosphinyl group, diethoxyphosphinyl group, etc.), phosphinyloxy group (eg, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, etc.), phosphinyl Amino group (for example, dimethoxyphosphinylamino group, dimethylamine Roh phosphinyl 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]
A₁~ A₄Examples of the preferable substituent include a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a carboxyl group, an alkoxycarbonyl group and the like. More preferred are a hydrogen atom and an alkyl group.
[0037]
R₁Preferred are a hydrogen atom, an alkyl group, an aryl group, an aryl group, and a heterocyclic group, and more preferred are a hydrogen atom and an alkyl group.
[0038]
R₂And R₃Are preferably a hydrogen atom, an alkyl group, an aryl group, and a heterocyclic group.
[0039]
R₁And R₂And R₂And R₃May combine with each other to form a ring structure. The ring structure formed may be either an aliphatic ring or an aromatic ring, and may be a hydrocarbon ring or a heterocyclic ring. R₁And R₂And R₂And R₃May be substituted by the substituents described above, or may be further condensed with another ring structure.
[0040]
Preferably R₂And R₃Preferably forms a ring structure, and more preferably forms an aromatic ring.
[0041]
R₄~ R₆Preferred are a hydrogen atom, an alkyl group, an aryl group, an aryl group, and a heterocyclic group, and more preferred are a hydrogen atom and an alkyl group.
[0042]
X is preferably a sulfur atom, NR₄Or CR₅R₆And n is preferably 1.
[0043]
Next, the general formulas (2) and (3) represented by Q will be described.
In the general formulas (2) and (3), B is CR₁₁Or a nitrogen atom, R₁₀And R₁₁Each represents a hydrogen atom or a substituent; Z represents a group of atoms necessary for forming a 5- or 6-membered ring, which may have a substituent, bonded by *, and having at least one It has a carboxyl group. The substituent herein has the same meaning as the substituent of the general formula (1).
[0044]
Further, in addition to the compound represented by the above general formula (1), it includes ions and salts derived from the compound. For example, when the compound represented by the general formula (1) has 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 counter cation And the salts formed with
[0045]
Such a salt may be a salt formed with a metal ion such as a sodium salt, a potassium salt, a magnesium salt, and 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 protonating the compound, and a hydrochloride, a sulfate, an acetate, a methyl sulfonate, a p-toluene sulfonate, etc. An inner salt formed with an acid is also included.
[0046]
R₁₀Preferred are a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a carboxyl group, an alkoxy group, and an amino group, and more preferred are an alkyl group, an aryl group, an alkoxy group and a carboxyl group.
[0047]
R₁₁Preferred are a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a carboxyl group, an alkoxycarbonyl group, a cyano group and a halogen atom, and more preferably a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, and a cyano group is there.
[0048]
In general formulas (2) and (3) represented by Q, atomic groups (partial structures) represented by the following general formulas (Cp-1) to (Cp-18) are preferably used.
[0049]
Here, the atomic groups represented by (Cp-1) to (Cp-18) are bonded to portions other than Q in the general formula (1) at the positions indicated by *. Further, Q according to the present invention is not limited by these.
[0050]
Embedded image

[0051]
Hereinafter, the compounds represented by formulas (Cp-1) to (Cp-18) will be described in detail.
[0052]
<< General formula (Cp-1), General formula (Cp-2) >>
In the general formulas (Cp-1) and (Cp-2), 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, respectively. , A ureido group, an alkoxycarbonylamino group, a carbamoyl group, a carboxyl group or an alkoxycarbonyl group.
[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-3), General formula (Cp-4) >>
In the general formulas (Cp-3) and (Cp-4), R₆₃And R₆₄Represents R represented by the general formulas (Cp-1) and (Cp-2).₆₃And R₆₄Is synonymous with
[0056]
R₆₅And 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, a ureido group, an alkoxycarbonyl group, respectively. Represents an amino group, an acyl group, a carboxyl group, an alkoxycarbonyl group or a carbamoyl group.
[0057]
Where R₆₅The group represented by preferably includes an alkyl group, an aryl group, an alkoxyl group, an aryloxy group and the like.₆₃, R₆₄, 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.
[0058]
<< General formula (Cp-5) >>
In the general formula (Cp-5), R₆₈And R₆₉Is a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonyl group, an arylsulfonylamino group, an amino group, an alkylthio group, an arylthio group, an alkoxyl group, an aryloxy group, a ureido group, an alkoxycarbonylamino group, respectively. , A carboxyl group, an acyl group, an alkoxycarbonyl group or a carbamoyl group.
[0059]
Where R₆₈, R₆₉The group represented by preferably includes a hydrogen atom, an alkyl group, an aryl group, a carboxyl group, and the like.
[0060]
<< General formulas (Cp-6) to (Cp-10) >>
In the general formulas (Cp-6) to (Cp-10), 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.
[0061]
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.
[0062]
<< General formulas (Cp-11) to (Cp-18) >>
In the general formulas (Cp-11) to (Cp-18), 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.
[0063]
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.
[0064]
Further, Q is preferably represented by the following general formulas a to d.
[0065]
Embedded image

[0066]
In the general formulas a to d, R₄'And R₅′ Each represents a hydrogen atom or a substituent, Z2 represents an atomic group necessary for forming a 5- or 6-membered ring, and may have a substituent, and bond with the substituent to form a condensed ring. May be combined with * other than Q. At least one has a carboxyl group. R₄'And R₅The substituent 'is the same as the substituent described above.
[0067]
To explain Z2 more 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.
[0068]
Embedded image

[0069]
The general formulas a-1 to a-3 and a-6 to a-9 are the same compounds as the general formulas (Cp-1) to (Cp-3) and (Cp-15) to (Cp-18). And R in general formulas a-4 and a-5₄', R₆', R₇'Is synonymous with them.
[0070]
R₄'~ R₇'Each represents a hydrogen atom or a substituent, and is preferably a structure of general formulas a-1, a-2, a-3, a-6 and a-7, more preferably a general formula a-1, a-3 and a-6.
[0071]
In formulas b to d, compounds having the same structure can be mentioned. For example, general formula b is general formulas (Cp-8), (Cp-10), (Cp-12) and (Cp-14), while general formula c is general formulas (Cp-6), (Cp-7), (Cp-9), (Cp-11) and (Cp-13), for example, general formula d includes general formulas (Cp-4) and (Cp-5), but is not limited thereto. .
[0072]
Next, the general formula (4) will be described.
In the general formula (4), A₁~ A₃Each represents a hydrogen atom or a substituent, and each may combine to form a ring; n represents an integer of 0 to 2;₂, R₃Each represents a hydrogen atom or a substituent, each of which may combine to form a ring, and X represents an oxygen atom, a sulfur atom, NR₄Or CR₅R₆Y represents a nitrogen atom or CR₇And R₄~ R₇Represents a hydrogen atom or a substituent, and Q is represented by the general formula (5) or (6).
[0073]
Here, the general formulas (5) and (6) have the same meanings as the general formulas (2) and (3) in the general formula (1), respectively.
[0074]
In the general formula (4), A₁~ A₃, R₂~ R₇Examples of the substituent in include the groups described in the general formula (1).₁~ A₃Examples of the preferable substituent include a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a carboxyl group, an alkoxycarbonyl group and the like. More preferred are a hydrogen atom and an alkyl group.
[0075]
R₂And R₃Are preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group and a heterocyclic group.
[0076]
R₂And R₃May combine with each other to form a ring structure. The ring structure formed may be either an aliphatic ring or an aromatic ring, and may be a hydrocarbon ring or a heterocyclic ring. R₂And R₃May be substituted by the substituents described above, or may be further condensed with another ring structure.
[0077]
Preferably R₂And R₃Preferably forms a ring structure, and more preferably forms an aromatic ring.
[0078]
R₄~ R₇Preferred are a hydrogen atom, an alkyl group, an aryl group, an aryl group, and a heterocyclic group, and more preferred are a hydrogen atom and an alkyl group.
[0079]
X is preferably a sulfur atom, NR₄Or CR₅R₆It is.
Next, the general formula (7) will be described.
[0080]
In the general formula (7), A₁~ A₄Each represents a hydrogen atom or a substituent, and each may combine to form a ring; n represents 0 or 1;₁~ R₃Each represents a hydrogen atom or a substituent, each of which may combine to form a ring, and X represents an oxygen atom, a sulfur atom, NR₄Or CR₅R₆And R₄~ R₆, R₈And R₉Represents a hydrogen atom or a substituent, and these preferred substituents have the same meanings as in formula (1).
[0081]
In the general formula (7), R₈Represents an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an amino group, an anilino group, a carboxyl group, an alkoxyl group, an aryloxy group, an alkylthio group, an arylthio group, a ureido group or an alkoxycarbonylamino group. R₉Represents an alkyl group, an aryl group or a heterocyclic group.
[0082]
Where R₈, R₉Each of the groups represented by has the same meaning as the group described in the description of the substituent.
[0083]
In the general formula (7), R₈Examples of the group represented by preferably include an alkyl group, an aryl group, an acylamino group, an amino group, an anilino group, a ureido group, an alkoxycarbonylamino group, a carboxyl group, and the like. More preferably, an aryl group, an acylamino group , Anilino group and carboxyl group.
[0084]
In the general formula (7), R₉The group represented by is preferably an alkyl group, an aryl group, or a heterocyclic group, and is more preferably an alkyl group or an aryl group.
[0085]
Next, the general formula (8) will be described.
In the general formula (8), A₁~ A₃Each represents a hydrogen atom or a substituent, and each may combine to form a ring; n represents an integer of 0 to 2;₂, R₃Each represents a hydrogen atom or a substituent, each of which may combine to form a ring, and X represents an oxygen atom, a sulfur atom, NR₄Or CR₅R₆Represents a nitrogen atom or CR₇And R₄~ R₉Represents a hydrogen atom or a substituent, and these preferred substituents have the same meanings as in formula (4). R₈And R₉Preferred substituents are the same as those in formula (7).
[0086]
Next, the general formula (9) will be described.
In the general formula (9), A₁~ A₄Each represents a hydrogen atom or a substituent, and each may combine to form a ring; n represents 0 or 1;₁~ R₃Each represents a hydrogen atom or a substituent, each of which may combine to form a ring, and X represents an oxygen atom, a sulfur atom, NR₄Or CR₅R₆And R₄~ R₆Represents a hydrogen atom or a substituent, and these preferred substituents have the same meanings as in formula (1).
[0087]
B₁Is a nitrogen atom or CR₇And R₇~ R₉Represents a hydrogen atom or a substituent, and the substituents are as described above.
[0088]
In the general formula (9), R₇Examples of the group represented by preferably include an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an amino group, a ureido group, an alkoxycarbonylamino group, a carboxyl group, and the like. More preferably, an alkyl group, an aryl group Group, acylamino group, alkoxycarbonyl group and carboxyl group.
[0089]
In the general formula (9), R₈Examples of the group represented by preferably include an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an amino group, a ureido group, an alkoxycarbonylamino group, a carboxyl group, and the like. More preferably, an alkyl group, an aryl group Group, heterocyclic group and carboxyl group.
[0090]
In the general formula (9), R₉Examples of the group represented by preferably include an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an amino group, a ureido group, an alkoxycarbonyl group, a carboxyl group, and the like. More preferably, an alkyl group and an aryl group , An acylamino group, an alkoxycarbonyl group, and a carboxyl group.
[0091]
Next, general formula (10) will be described.
In the general formula (10), A₁~ A₃Each represents a hydrogen atom or a substituent, and each may combine to form a ring; n represents an integer of 0 to 2;₂, R₃Each represents a hydrogen atom or a substituent, each of which may combine to form a ring, and X represents an oxygen atom, a sulfur atom, NR₄Or CR₅R₆And R₄~ R₆Represents a hydrogen atom or a substituent, and these preferred substituents have the same meanings as in formula (4).
[0092]
Y and B₁Is a nitrogen atom or CR₇And R₇~ R₉Represents a hydrogen atom or a substituent, and the substituent is as described above. R₇~ R₉Is preferably the same as defined in general formula (9).
[0093]
Among the compounds represented by the general formulas (1), (4), and (7) to (10) according to the present invention, particularly preferably used are the compounds represented by the general formulas (1), (7) or (7). A compound represented by the general formula (9), and among them, as Q, a pyrazoloazole compound having the general formula (Cp-1) or (Cp-2), or having the general formula (Cp-3) Pyrazoloimidazole compounds, imidazopyrazole compounds having the general formula (Cp-4), pyrrolotriazole compounds having the general formula (Cp-6), and pyrazolopyrimidine-7- having the general formula (Cp-15) On compounds are preferred.
[0094]
Hereinafter, specific examples of the compounds represented by Formulas (1), (4), and (7) to (10) according to the present invention are shown, but the present invention is not limited thereto.
[0095]
First, specific examples of the general formulas (2), (3), (5) and (6) in the general formulas (1) and (4) are shown, but the present invention is not limited thereto.
[0096]
Embedded image

[0097]
Embedded image

[0098]
Embedded image

[0099]
Embedded image

[0100]
Embedded image

[0101]
Embedded image

[0102]
Next, specific examples of the above general formulas (1) and (4) are shown, but it goes without saying that the present invention is not limited to these.
[0103]
Embedded image

[0104]
Embedded image

[0105]
Embedded image

[0106]
Embedded image

[0107]
Embedded image

[0108]
Embedded image

[0109]
Embedded image

[0110]
Embedded image

[0111]
Next, specific examples of general formulas (7) to (10) are shown, but it goes without saying that the present invention is not limited to these.
[0112]
Embedded image

[0113]
Embedded image

[0114]
Embedded image

[0115]
Embedded image

[0116]
Embedded image

[0117]
Embedded image

[0118]
Embedded image

[0119]
Embedded image

[0120]
The compounds represented by the general formulas (1), (4) and (7) to (10) according to the present invention are described in, for example, JP-A-10-60296, JP-A-2000-191934 and the like. The compound can be synthesized with reference to the conventionally known methods described above.
[0121]
Specific examples of the synthesis method are shown below, but other compounds can be synthesized in the same manner, and the synthesis method is not limited thereto.
[0122]
Synthesis Example 1
Synthesis of Exemplified Compound I-27
1) Synthesis route
[0123]
Embedded image

[0124]
2) Synthesis of Exemplified Compound I-27
60 ml of ethanol, 0.66 g of potassium acetate and 3.24 g of intermediate 2 are added to 2.00 g of intermediate 1: heat reaction at 50 ° C. for 3 hours. Thereafter, the mixture is heated and refluxed for 1 hour, and cooled after completion of the reaction. The precipitated crystals were filtered and washed with ethyl acetate to obtain 2.94 g of Exemplified Compound I-27. 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 630 nm.
[0125]
Synthesis Example 2
Synthesis of Exemplified Compound II-7
1) Synthesis route
[0126]
Embedded image

[0127]
2) Synthesis of Exemplified Compound II-7
To 2.04 g of the intermediate 3, 25 ml of toluene, 0.74 g of morpholine and 1.51 g of the intermediate 4 were added, and the mixture was heated and refluxed for 3 hours. After completion of the reaction, the mixture is cooled to room temperature. The precipitated crystals were filtered and washed with ethyl acetate to obtain 2.82 g of Exemplified Compound II-7. It was identified by MASS, H-NMR, and IR spectrum, and it was confirmed that it was a target.
[0128]
Synthesis Example 3
Synthesis of Exemplified Compound III-1
1) Synthesis route
[0129]
Embedded image

[0130]
2) Synthesis of exemplified compound III-1
To 2.33 g of Intermediate 5 were added 120 ml of ethanol, 1.32 g of potassium acetate and 5.90 g of Intermediate 6 and reacted by heating at 60 ° C. for 3 hours. Thereafter, the mixture is heated and refluxed for 1 hour, and cooled after completion of the reaction. The precipitated crystals were filtered and washed with ethyl acetate to obtain 4.74 g of Exemplified Compound III-1. It was identified by MASS, H-NMR, and IR spectrum, and it was confirmed that it was a target.
[0131]
Synthesis Example 4
Synthesis of Exemplified Compound IV-4
1) Synthesis route
[0132]
Embedded image

[0133]
2) Synthesis of exemplified compound IV-4
Ethanol: 120 ml, potassium acetate: 1.32 g, and intermediate 8: 5.66 g were added to 2.26 g of intermediate 7, and the mixture was heated and reacted at 60 ° C. for 3 hours. Thereafter, the mixture is heated and refluxed for 1 hour, and cooled after completion of the reaction. The precipitated crystals were filtered and washed with ethyl acetate to obtain 4.18 g of Exemplified Compound IV-4. It was identified by MASS, H-NMR, and IR spectrum, and it was confirmed that it was a target.
[0134]
《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 compounds represented by the general formulas (1), (4) and (7) to (10), and is described in the present invention. The effect of (1) can be achieved. Here, the expression "comprising the compound" means 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.
[0135]
In addition, 1 m of a semiconductor layer (may be a semiconductor)²The total content of each compound represented by the above general formulas (1), (4) and (7) to (10) is preferably in the range of 0.01 to 100 mmol, more preferably 0 to 100 mmol. 0.1 mmol to 50 mmol, particularly preferably 0.5 mmol to 20 mmol.
[0136]
When sensitization is performed using any one of the compounds represented by the general formulas (1), (4) and (7) to (10) according to the present invention, the compound may be used alone. It is preferable to use a combination of two or more of the compounds represented by the general formulas (1), (4) and (7) to (10) according to the present invention with another compound (for example, US Pat. Nos. 4,684,537, 4,927,721, 5,084,365, 5,350,644, and 5,463,057. No. 5,525,440, and the compounds described in JP-A-7-249790, JP-A-2000-150007, etc.). .
[0137]
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.
[0138]
In order for a semiconductor to contain any one of the compounds represented by the general formulas (1), (4) and (7) to (10), the compound is dissolved in an appropriate solvent (such as ethanol). Generally, a method of immersing a well-dried semiconductor in the solution for a long time is used.
[0139]
A semiconductor for a photoelectric conversion material in which a plurality of any one of the compounds represented by the general formulas (1), (4) and (7) to (10) are used in combination, or another sensitizing dye compound is used in combination. When preparing a compound, a mixed solution of each compound may be prepared and used, or a solution of each compound may be prepared 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, it may be produced by mixing semiconductor fine particles adsorbing the compound alone.
[0140]
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. The solution in which the compound used for the adsorption treatment is dissolved may be used at room 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 compound may be adsorbed by simultaneously applying the semiconductor fine particles and the compound of the present invention. Unadsorbed compounds can be removed by washing.
[0141]
In the sensitization treatment of the semiconductor for a photoelectric conversion material of the present invention, the semiconductor includes any one of the compounds represented by the general formulas (1), (4), and (7) to (10). Thus, the sensitization process is performed, and the details of the sensitization process will be specifically described in a photoelectric conversion element described later.
[0142]
Further, in the case of a semiconductor for a photoelectric conversion material having a semiconductor film having a high porosity, the compound or the sensitizer is used before water is adsorbed on the semiconductor thin film by water, water vapor, or the like in the voids, and in the voids inside the semiconductor thin film. It is preferable to complete the adsorption treatment of the dye compound or the like (sensitization treatment of the semiconductor for a photoelectric conversion material).
[0143]
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.
[0144]
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. .
[0145]
In addition, the dyes that can be used in combination with any one of the compounds represented by the general formulas (1), (4), and (7) to (10) according to the present invention include those according to the present invention. Any dye that can spectrally sensitize a semiconductor 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.
[0146]
Among the dyes according to the present invention, metal complex dyes, phthalocyanine dyes, porphyrin dyes, and polymethine dyes are preferably used from a comprehensive viewpoint such as photoelectron transfer reaction activity, light durability, and photochemical stability.
[0147]
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 989/50393. Ruthenium complex dyes are preferably used.
[0148]
Examples of the porphyrin-based dye and the phthalocyanine-based dye include the dyes described in JP-A-2001-223037 as preferred dyes.
[0149]
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.
[0150]
<< 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.
[0151]
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.
[0152]
When the semiconductor for a photoelectric conversion material of the present invention is produced by firing, the sensitization (adsorption, penetration into porous material, etc.) treatment of the semiconductor using the above compound 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.
[0153]
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.
[0154]
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.
[0155]
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.
[0156]
<< 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.
[0157]
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.
[0158]
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.
[0159]
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).
[0160]
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).
[0161]
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.
[0162]
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.
[0163]
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 a titanium aqueous solution may be performed.
[0164]
《Semiconductor sensitization》
As described above, the sensitization treatment of a semiconductor is performed by dissolving a dye in an appropriate solvent and immersing the substrate obtained by firing the semiconductor in the solution. In that case, the substrate on which the semiconductor layer (also referred to as a semiconductor film) is formed by firing is subjected to a reduced pressure treatment or a heat treatment in advance to remove bubbles in the film, and the above general formulas (1) and (4) And it is preferable that any one of the compounds (7) to (10) can penetrate deep inside the semiconductor layer (semiconductor film). In the case where the semiconductor layer (semiconductor film) is a porous structure film, Is particularly preferred.
[0165]
"solvent"
The solvent used to dissolve any one of the compounds represented by the general formulas (1), (4) and (7) to (10) can dissolve the compound and dissolve a semiconductor. There is no particular limitation as long as it does not react with the semiconductor, but water and gas dissolved in the solvent enter the semiconductor film and prevent sensitization treatment such as adsorption of the compound. In order to prevent this, it is preferable to perform degassing and distillation purification in advance.
[0166]
In dissolving the compound, preferably used solvents are methanol, ethanol, alcohol solvents such as n-propanol, acetone, ketone solvents such as methyl ethyl ketone, ether ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran and 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.
[0167]
《Temperature and time of sensitization treatment》
The time for immersing the substrate after firing the semiconductor in a solution containing any one of the compounds represented by the general formulas (1), (4) and (7) to (10) is as follows. Penetrates deeply to sufficiently advance adsorption and the like, sufficiently sensitize the semiconductor, and suppress a decomposition product generated by decomposition of the compound in a solution or the like to inhibit the adsorption of the compound. Therefore, under 25 ° C. conditions, the time 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.
[0168]
Upon immersion, a solution containing one of the compounds of the general formulas (1), (4) and (7) to (10) is heated to a temperature at which the compound does not boil unless the compound is decomposed. May be used. 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 as described above.
[0169]
《Photoelectric conversion element》
The photoelectric conversion element of the present invention will be described with reference to FIG.
[0170]
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.
[0171]
Here, the photosensitive layer 2 is a layer having 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 form.
[0172]
<< Method of manufacturing photoelectric conversion element >>
A method for manufacturing a photoelectric conversion element will be described with reference to FIG.
[0173]
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 by using the plasma processing apparatus as described above, and then the general formula (1) according to the present invention is obtained. , (4) and (7) to (10).
[0174]
Further, the surface area of the semiconductor thin film is increased or impurities on the surface of the semiconductor thin film are removed to increase the purity of the semiconductor, and are represented by the general formulas (1), (4) and (7) to (10). For example, chemical plating using an aqueous solution of titanium tetrachloride or electrochemical plating using an aqueous solution of titanium trichloride may be performed in order to increase the efficiency of electron injection from any one compound into a semiconductor.
[0175]
The semiconductor film formed on the conductive support 1 is made to adsorb any one of the compounds represented by the above general formulas (1), (4) and (7) to (10) to form a semiconductor film. To form a photosensitive layer 2. As described above, the sensitization method is performed by dissolving the compound in an appropriate solvent and immersing the semiconductor film formed on the conductive support 1 in the solution. At that time, the semiconductor film is subjected to a reduced pressure treatment or a heat treatment in advance to remove bubbles in the film, and any of the compounds represented by the above general formulas (1), (4) and (7) to (10). It is preferable that at least one compound can enter deep inside the semiconductor film.
[0176]
When adsorbing any one of the compounds represented by the general formulas (1), (4) and (7) to (10) on the semiconductor according to the present invention, the compound may be used alone, You may use two or more together. 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, JP-A-2000-150007, etc.).
[0177]
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.
[0178]
The semiconductor for a photoelectric conversion material sensitized by using a plurality of any one of the compounds represented by the general formulas (1), (4), and (7) to (10) described above in combination It may be prepared by immersing in a solution prepared by mixing compounds, or by preparing a solution for each compound and immersing it in each solution in order.
[0179]
When preparing a separate solution for each compound and immersing it in each solution in order, the effects of the present invention can be obtained in any order of adsorbing the compound or the conventionally known sensitizing dye to the semiconductor. Can be obtained.
[0180]
In the adsorption treatment, a solution in which the compound is dissolved may be used at normal temperature, or the solution may be heated to a temperature 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.
[0181]
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.
[0182]
《Solar cell》
The solar cell of the present invention will be described.
[0183]
As shown in FIG. 1, the solar cell of the present invention has an optimal design and circuit design for sunlight as one mode of the photoelectric conversion element of the present invention, and has an optimal photoelectric conversion when sunlight is used as a light source. It has a structure in which conversion is performed. In other words, 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.
[0184]
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 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 via the redox electrolyte of the charge transfer layer 3 to be reduced to the original form. 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.
[0185]
《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.
[0186]
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 transparent conductive support 1 is used, it is preferable that light is incident from the support side.
[0187]
The conductive support has a surface resistance of 50Ω / cm.²Preferably 10 Ω / cm²It is more preferred that:
[0188]
《Charge transfer layer》
The charge transfer layer used in the present invention will be described.
[0189]
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.
[0190]
《Counter electrode》
The counter electrode used in the present invention will be described.
[0191]
The counter electrode may be any material having 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 subjecting a conductive material to platinum plating or platinum deposition, rhodium metal, ruthenium metal, ruthenium oxide, carbon, and the like.
[0192]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[0193]
Example 1
<< Preparation of photoelectric conversion element 1 >>
A photoelectric conversion device as shown in FIG. 1 was produced as described below.
[0194]
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 coated with fluorine-doped tin oxide, dried naturally, and baked at 300 ° C. for 60 minutes to form a film-like titanium oxide on the support. did.
[0195]
Next, a solution in which 5 g of Exemplified Compound I-2 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 photoelectric conversion material) was washed with chloroform and dried in vacuum to prepare a photosensitive layer 2 (semiconductor for photoelectric conversion material).
[0196]
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 volume ratio between the conductive support 1 and the counter electrode 4 is 1 Redox electrolyte in which tetrapropylammonium iodide and iodine were dissolved at a concentration of 0.46 mol / l and 0.06 mol / l, respectively, in a mixed solvent of acetonitrile / ethylene carbonate of 4: The charge transfer layer 3 was manufactured, and the photoelectric conversion element 1 was manufactured.
[0197]
<< Preparation of photoelectric conversion elements 2-20 >>: The present invention
Photoelectric conversion elements 2 to 20 were obtained in the same manner as in the production of photoelectric conversion element 1, except that Exemplified Compound I-2 was changed to the compound shown in Table 1.
[0198]
<< 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 comparative compound R1 shown in Table 1 was used.
[0199]
Embedded image

[0200]
<< Production of solar cells SC-1 to SC-20 >>: The present invention
After enclosing the side surface of the photoelectric conversion element 1 with resin, lead wires were attached, and solar cells SC-1 to SC-20 of the present invention were manufactured in three lots each.
[0201]
<< Preparation of Solar Cell SC-R1 >>: Comparative Example
In the production of the solar cell SC-1, three lots of the solar cell SC-R1 were produced in the same manner except that the comparative photoelectric conversion element R1 was used.
[0202]
<< Evaluation of photoelectric conversion characteristics of solar cells >>
Each of the solar cells SC-1 to SC-20 and the solar cell SC-R1 obtained above was subjected to a solar simulator (manufactured by JASCO (JASCO), low energy spectral sensitivity measurement apparatus CEP-25) at 100 mW / m.²Current density Jsc (mA / cm²) And the open-circuit voltage value Voc (V) were measured and are shown in Table 1. The values shown are the average values of the measurement results for three solar cells having the same configuration and manufacturing method.
[0203]
[Table 1]

[0204]
As shown in Table 1, the solar cell of the present invention shows higher photoelectric conversion characteristics than the comparison, and it is possible to use any one of the compounds represented by the general formulas (1), (7) and (9). It turns out to be effective. In addition, the solar cells SC-1 to SC-20 of the present invention were 100 mW / m2 by a solar simulator.²No decrease in photoelectric conversion efficiency was observed even after 100 hours of light irradiation, and it was clarified that the stability was excellent.
[0205]
Example 2
<< Preparation of photoelectric conversion elements 101-120, R2 >>
In the production of the photoelectric conversion device 1 described in Example 1, the photoelectric conversion devices 101 to 120 and R2 were produced in the same manner except that the exemplified compound I-2 was changed to the compounds described in Table 2.
[0206]
Embedded image

[0207]
<< Solar cells SC-101 to SC-120: present invention, SC-R2: production of comparative example >>
In the production of the solar cell SC-1 described in Example 1, the solar cells SC-101 to SC-120 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.
[0208]
<< Evaluation of photoelectric conversion characteristics of solar cells >>
Each of the solar cells SC-101 to SC-120 and the solar cell SC-R2 obtained above was supplied with a solar simulator (manufactured by JASCO (JASCO), low energy spectral sensitivity measuring apparatus CEP-25) to 100 mW / m.²Current density Jsc (mA / cm²) And the open-circuit voltage value Voc (V) were measured and are shown in Table 2. The values shown are the average values of the measurement results for three solar cells having the same configuration and manufacturing method.
[0209]
[Table 2]

[0210]
As shown in Table 2, the solar cell of the present invention shows higher photoelectric conversion characteristics than the comparison, and it is possible to use any one of the compounds represented by the general formulas (4), (8) and (10). It turns out to be effective. In addition, the solar cells SC-101 to SC-120 of the present invention were measured at 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 clarified that the stability was excellent.
[0211]
【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 following general formula (1).

(Wherein, A _{1 to} A ₄ each represent a hydrogen atom or a substituent, and each may combine to form a ring, n represents 0 or 1, and R _{1 to} R ₃ each represent a hydrogen atom or a substituent. X represents an oxygen atom, a sulfur atom, NR ₄ or CR ₅ R ₆ ; R _{4 to} R ₆ each represent a hydrogen atom or a substituent; Is represented by the following general formula (2) or (3))

(Wherein, B represents CR ₁₁ or a nitrogen atom, R ₁₀ and R ₁₁ each represent a hydrogen atom or a substituent, Z represents an atom group necessary for forming a 5- or 6-membered ring, and a substituent May be bonded by * and have at least one carboxyl group in the molecule.) A semiconductor for a photoelectric conversion material, comprising a dye represented by the following general formula (4).

(Wherein, A _{1 to} A ₃ each represent a hydrogen atom or a substituent, and each may combine to form a ring, n represents an integer of 0 to ₂ , and R ₂ and R ₃ each represent a hydrogen atom Or a substituent, each of which may combine to form a ring, X represents an oxygen atom, a sulfur atom, NR ₄ or CR ₅ R ₆ , Y represents a nitrogen atom or CR ₇ , and R _{4 to} R ₇ represents a hydrogen atom or a substituent, and Q is represented by the following general formula (5) or (6))

(Wherein, B represents CR ₁₁ or a nitrogen atom, R ₁₀ and R ₁₁ each represent a hydrogen atom or a substituent, Z represents an atom group necessary for forming a 5- or 6-membered ring, and a substituent May be bonded by * and have at least one carboxyl group in the molecule.) A semiconductor for a photoelectric conversion material, comprising at least one dye represented by the following general formula (7) or (8).

(Wherein, A _{1 to} A ₄ each represent a hydrogen atom or a substituent, and each may combine to form a ring, n represents 0 or 1, and R _{1 to} R ₃ each represent a hydrogen atom or a substituent. X represents an oxygen atom, a sulfur atom, NR ₄ or CR ₅ R ₆ , and R _{4 to} R ₆ , R ₈ and R ₉ each represent a hydrogen atom or Represents a substituent.)

(Wherein, A _{1 to} A ₃ each represent a hydrogen atom or a substituent, and each may combine to form a ring, n represents an integer of 0 to ₂ , and R ₂ and R ₃ each represent a hydrogen atom Or a substituent, each of which may combine to form a ring, X represents an oxygen atom, a sulfur atom, NR ₄ or CR ₅ R ₆ , Y represents a nitrogen atom or CR ₇ , and R _{4 to} R ₉ represents a hydrogen atom or a substituent.) A semiconductor for a photoelectric conversion material, comprising at least one dye represented by the following general formula (9) or (10).

(Wherein, A _{1 to} A ₄ each represent a hydrogen atom or a substituent, and each may combine to form a ring, n represents 0 or 1, and R _{1 to} R ₃ each represent a hydrogen atom or a substituent. X represents an oxygen atom, a sulfur atom, NR ₄ or CR ₅ R ₆ , B ₁ represents a nitrogen atom or CR ₇ , and R _{4 to} R ₉ Each represents a hydrogen atom or a substituent.)

(Wherein, A _{1 to} A ₃ each represent a hydrogen atom or a substituent, and each may combine to form a ring, n represents an integer of 0 to ₂ , and R ₂ and R ₃ each represent a hydrogen atom Or a substituent, each of which may combine to form a ring, X represents an oxygen atom, a sulfur atom, NR ₄ or CR ₅ R ₆ , Y and B ₁ represent a nitrogen atom or CR ₇ , R ₄ to R ₉ each represents a hydrogen atom or a substituent.) The Q of the dye according to claim 1 or 2, wherein Q is the following general formulas (Cp-1), (Cp-2), (Cp-3), (Cp-4), (Cp-6), and (Cp-15). A semiconductor for a photoelectric conversion material, which is represented by any one of the above.

(Wherein, in the general formulas (Cp-1) and (Cp-2), 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, Represents an arylsulfonylamino group, an amino group, an alkylamino group, an alkylthio group, an arylthio group, an alkoxyl group, an aryloxy group, a ureido group, an alkoxycarbonylamino group, a carbamoyl group, a carboxyl group or an alkoxycarbonyl group, and has the general formula (Cp- 3) in _{(Cp-4), R 63} and _{R 64,} the formula (Cp-1), have the same meanings as _{R 63} and _{R 64} described in _{(Cp-2), R 65} and _{R 67} , A hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an acylamino group, an alkylsulfonylamino group, an aryls Represents a honylamino group, an amino group, an alkylthio group, 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, and in the general formula (Cp-6) , 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, 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; and in the general formula (Cp-15), R ₉₁ represents an alkyl group, an aryl group, a heterocyclic group, a carbamoyl group, Alkoxycarbonyl group, aryl Represents a luoxycarbonyl group, a carboxyl group, a cyano group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a nitro group, and R ₉₃ and R ₉₄ each represent a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, or 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, an alkoxyl group or an aryloxy group. I have one.) The semiconductor for a photoelectric conversion material according to any one of claims 1 to 5, wherein the semiconductor 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 5 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.

Images