JP2004319130A - Manufacturing method of photoelectric transfer device, photoelectric transfer element, manufacturing method of electronic device, electronic device and forming method of semiconductor particulate layer and laminate structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a photoelectric transfer element in which a semiconductor electrode made of semiconductor particulates can be formed excellently on a metal oxide membrane while preventing elution of the metal oxide membrane, and at a low temperature process, and a photoelectric transfer element. <P>SOLUTION: In the photoelectric transfer element having a semiconductor electrode made of semiconductor particulates and a metal membrane to be a counter electrode, polyethylenedioxothiophene (PEDOT)/ polystyrene sulfonic acid (PSS) membrane 13 are formed by a spin coat on a transparent electrode 12 made of a metal oxide such as ITO, and then a semiconductor particulate layer 14 made of titanium oxide particulate or the like is formed by spin coating the semiconductor particulate dispersion solution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

で示されるポリチオフェンまたはその誘導体と、
【化１９】

で示されるポリスチレンスルホン酸、ＲＳＯ_３ Ｈ（ただし、Ｒ＝アルキル、アリール）、Ｒ´ＯＳＯ_３ Ｈ（ただし、Ｒ´＝Ｈ、アルキル、アリール）、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ からなる群より選ばれた少なくとも一種類の化合物とからなる中間膜を製膜し、この中間膜上に半導体電極を形成するようにした
ことを特徴とするものである。
【００１５】
この発明の第２の発明は、
金属酸化物膜上に半導体微粒子からなる半導体電極を有する光電変換素子において、
金属酸化物膜上に、
【化２０】

で示されるポリチオフェンまたはその誘導体と、
【化２１】

で示されるポリスチレンスルホン酸、ＲＳＯ_３ Ｈ（ただし、Ｒ＝アルキル、アリール）、Ｒ´ＯＳＯ_３ Ｈ（ただし、Ｒ´＝Ｈ、アルキル、アリール）、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ からなる群より選ばれた少なくとも一種類の化合物とからなる中間膜を製膜し、この中間膜上に半導体電極を形成した
ことを特徴とするものである。
【００１６】
第１および第２の発明において、ポリスチレンスルホン酸、ＲＳＯ_３ Ｈ、Ｒ´ＯＳＯ_３ Ｈ、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ は、ポリチオフェンまたはその誘導体に対してドーパントとなり、これらの化合物により導電性高分子が構成される。
【００１７】
中間膜は、最も典型的には、
【化２２】

で示されるポリエチレンジオキシチオフェンと、
【化２３】

で示されるポリスチレンスルホン酸とからなる、すなわちＰＥＤＯＴ／ＰＳＳからなる。この中間膜は、最も典型的には、
【化２４】

で示されるポリエチレンジオキシチオフェンと、
【化２５】

で示されるポリスチレンスルホン酸イオンと、
【化２６】

で示されるポリスチレンスルホン酸とを含む水溶液を用い、これを金属酸化物膜上にスピンコートすることなどにより製膜される。
【００１８】
中間膜の厚さは、数ｎｍ程度であっても下地の金属酸化物膜に対する付着性およびこの中間膜に対する半導体微粒子層の付着性の向上を図ることが可能であるが、強酸に対する金属酸化物膜の保護作用を高める観点からは、好適には１５ｎｍ以上、より好適には３０ｎｍ以上、さらに好適には６０ｎｍ以上とする。中間膜の厚さの上限は本質的には存在しないが、製膜コストの低減を図る観点より、好適には５００ｎｍ以下、より好適には４００ｎｍ以下とする。すなわち、中間膜の厚さは、好適には１５ｎｍ以上５００ｎｍ以下、より好適には３０ｎｍ以上４００ｎｍ以下、さらに好適には６０ｎｍ以上４００ｎｍ以下とする。
上記の中間膜は、半導体電極の対極となる白金膜などの金属膜の下地の金属酸化物膜に対する付着性の向上のために用いることもできる。
【００１９】
金属酸化物膜は、例えば、Ｉｎ−Ｓｎ複合酸化物、ＳｎＯ_２ （フッ素ドープＳｎＯ_２ （ＦＴＯ）も含む）、ＴｉＯ_２ およびＺｎＯからなる群より選ばれた少なくとも一種類の金属酸化物からなり、典型的には透明電極として用いられる。
金属酸化物膜は、典型的には、導電性または非導電性の透明支持基板上に製膜される。この透明支持基板の材質は特に制限されず、透明であれば種々の基材を用いることができるが、光電変換素子外部から侵入する水分やガスの遮断性、耐溶剤性、耐候性などに優れているものが好ましい。この透明支持基板としては、具体的には、石英、ガラスなどの透明無機基板、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリカーボネート、ポリスチレン、ポリエチレン、ポリプロピレン、ポリフェニレンサルファイド、ポリフッ化ビニリデン、テトラアセチルセルロース、ブロム化フェノキシ、アラミド類、ポリイミド類、ポリスチレン類、ポリアリレート類、ポリスルフォン類、ポリオレフィン類などの透明プラスチック基板が挙げられるが、これらに限定されるものではない。この透明支持基板としては、加工性、軽量性、フレキシビリティーなどを考慮すると、特にポリエチレンテレフタレートなどに代表される透明プラスチック基板を用いるのが好ましい。この透明支持基板の厚さは特に制限されず、光の透過率、光電変換素子の内部と外部との遮断性などによって自由に選択することができる。
【００２０】
半導体電極を構成する半導体微粒子の材料としては、シリコンに代表される元素半導体のほかに、各種の化合物半導体、ペロブスカイト構造を有する化合物などを使用することができる。これらの半導体は、光励起下で伝導帯電子がキャリアーとなり、アノード電流を与えるｎ型半導体であることが好ましい。これらの半導体は、具体的に例示すると、ＴｉＯ_２ 、ＺｎＯ、ＷＯ_３ 、Ｎｂ_２ Ｏ_５ 、ＴｉＳｒＯ_３ 、ＳｎＯ_２ などであり、これらのうちＴｉＯ_２ 、特にアナターゼ型結晶のＴｉＯ_２ が光触媒活性の点から特に好ましい。このアナターゼ型ＴｉＯ_２ は市販の粉末、ゾル、スラリーでもよいし、あるいは酸化チタンアルコキシドを加水分解するなどの公知の方法によって所定の粒径のものを作ってもよい。半導体の種類はこれらに限定されるものではなく、これらの半導体を二種類以上混合して用いることもできる。
【００２１】
半導体微粒子の粒径に特に制限はないが、一次粒子の平均粒径で１〜２００ｎｍが好ましく、特に好ましくは５〜１００ｎｍである。また、この平均粒径の半導体微粒子にこの平均粒径より大きい平均粒径の半導体微粒子を混合し、平均粒径の大きい半導体微粒子により入射光を散乱させ、量子収率を向上させることも可能である。この場合、別途混合する半導体微粒子の平均粒径は２０〜５００ｎｍであることが好ましい。
【００２２】
半導体微粒子からなる半導体電極の形成方法は、特に制限はないが、物性、利便性、製造コストなどを考慮した場合には湿式製膜法が好ましく、半導体微粒子の粉末あるいはゾルを水などの溶媒に均一分散し、導電性または非導電性の透明支持基板上に金属酸化物膜を形成した透明導電性基板上に塗布する方法が好ましい。塗布方法は特に制限はなく、公知の各種の方法を用いることができ、例えば、スピンコート法、ローラーコート法、ディップ法、スプレー法、ワイヤーバー法、ブレードコート法、グラビアコート法、また、湿式印刷方法としては、例えば、凸版、オフセット、グラビア、凹版、ゴム版、スクリーン印刷などの各種の方法を用いることができる。半導体微粒子として市販の粉末を使用する際には粒子の二次凝集を解消することが好ましく、塗布液調製時に乳鉢やボールミルなどを使用して粒子の粉砕を行うことが好ましい。このとき、二次凝集が解かれた粒子が再度凝集するのを防ぐため、アセチルアセトン、塩酸、硝酸、界面活性剤、キレート剤などを添加するのが好ましい。また、増粘の目的でポリエチレンオキシドやポリビニルアルコールなどの高分子、セルロース系の増粘剤などの各種増粘剤を添加することもできる。
【００２３】
半導体微粒子に担持させる色素としては、増感作用を示すものであれば特に制限はないが、例えば、ローダミンＢ、ローズベンガル、エオシン、エリスロシンなどのキサンテン系色素、キノシアニン、クリプトシアニンなどのシアニン系色素、フェノサフラニン、カブリブルー、チオシン、メチレンブルーなどの塩基性染料、クロロフィル、亜鉛ポルフィリン、マグネシウムポルフィリンなどのポルフィリン系化合物、その他アゾ色素、フタロシアニン化合物、クマリン系化合物、Ｒｕビピリジン錯化合物、アントラキノン系色素、多環キノン系色素などが挙げられる。この中でも、ルテニウム（Ｒｕ）ビピリジン錯化合物は量子収率が高く特に好ましいが、これに限定されるものではなく、単独もしくは２種類以上混合して用いることができる。
【００２４】
上記色素の半導体微粒子層への担持方法に特に制限はなく、例えば上記色素をアルコール類、ニトリル類、ニトロメタン、ハロゲン化炭化水素、エーテル類、ジメチルスルホキシド、アミド類、Ｎ−メチルピロリドン、１，３−ジメチルイミダゾリジノン、３−メチルオキサゾリジノン、エステル類、炭酸エステル類、ケトン類、炭化水素、水などの溶媒に溶解させ、その中に半導体微粒子層を浸漬し、もしくは色素溶液を半導体微粒子層に塗布する方法が一般的である。この場合、１半導体微粒子に対する色素分子の仕込み量は好ましくは１〜１０００分子であり、１〜１００分子がさらに好ましい。また、色素分子が半導体微粒子に対して大過剰に担持された場合、光エネルギーによって励起された電子が半導体微粒子に注入されず電解質を還元するためエネルギーロスの原因となる。従って、色素分子は半導体微粒子に対して単分子吸着が理想的な状態であり、必要に応じて担持させる温度や圧力を変化させることが可能である。色素同士の会合を低減する目的でデオキシコール酸などのカルボン酸類を添加してもよい。また紫外線吸収剤を併用することもできる。
【００２５】
過剰に吸着した色素の除去を促進する目的で、色素が吸着した後にアミン類を用いて半導体微粒子層の表面を処理してもよい。アミン類の例としては、ピリジン、４−ｔｅｒｔ−ブチルピリジン、ポリビニルピリジンなどが挙げられ、これらが液体の場合はそのまま用いてもよいし有機溶媒に溶解して用いてもよい。
【００２６】
対極は導電性物質であれば任意のものを用いることができるが、絶縁性の物質でも、半導体電極に面している側に導電層が設置されていれば、これも使用可能である。ただし、電気化学的に安定である材料を電極材料として用いることが好ましく、具体的には、白金、金、導電性高分子、カーボンなどを用いることが望ましい。また、酸化還元の触媒効果を向上させる目的で、半導体層に面している側は微細構造で表面積が増大していることが好ましく、例えば、白金であれば白金黒状態に、カーボンであれば多孔質状態になっていることが望まれる。白金黒状態は、白金の陽極酸化法、塩化白金酸処理などによって、また、多孔質状態のカーボンは、カーボン微粒子の焼結や有機ポリマーの焼成などの方法により形成することができる。
【００２７】
電解質は、ヨウ素（Ｉ_２ ）と金属ヨウ化物もしくは有機ヨウ化物との組み合わせ、臭素（Ｂｒ_２ ）と金属臭化物あるいは有機臭化物との組み合わせのほか、フェロシアン酸塩／フェリシアン酸塩やフェロセン／フェリシニウムイオンなどの金属錯体、ポリ硫化ナトリウム、アルキルチオール／アルキルジスルフィドなどのイオウ化合物、ビオロゲン色素、ヒドロキノン／キノンなどを用いることができる。上記金属化合物のカチオンとしては、Ｌｉ、Ｎａ、Ｋ、Ｍｇ、Ｃａ、Ｃｓなど、上記有機化合物のカチオンとしては、テトラアルキルアンモニウム類、ピリジニウム類、イミダゾリウム類などの４級アンモニウム化合物が好ましいが、これらに限定されるものではなく、これらを２種類以上混合して用いることもできる。この中でも、Ｉ_２ と、ＬｉＩ、ＮａＩやイミダゾリウムヨーダイドなどの４級アンモニウム化合物とを組み合わせた電解質が好適である。電解質塩の濃度は溶媒に対して０．０５〜５Ｍが好ましく、さらに好ましくは０．２〜１Ｍである。Ｉ_２ やＢｒ_２ の濃度は０．０００５〜１Ｍが好ましく、さらに好ましくは０．０００１〜０．１Ｍである。また、開放電圧、短絡電流を向上させる目的で、４−ｔｅｒｔ−ブチルピリジンやカルボン酸などの各種添加剤を加えることもできる。
【００２８】
上記電解質組成物を構成する溶媒として水、アルコール類、エーテル類、エステル類、炭酸エステル類、ラクトン類、カルボン酸エステル類、リン酸トリエステル類、複素環化合物類、ニトリル類、ケトン類、アミド類、ニトロメタン、ハロゲン化炭化水素、ジメチルスルホキシド、スルフォラン、Ｎ−メチルピロリドン、１，３−ジメチルイミダゾリジノン、３−メチルオキサゾリジノン、炭化水素などが挙げられるが、これらに限定されるものではなく、単独もしくは２種類以上混合して用いることができる。また、溶媒としてテトラアルキル系、ピリジニウム系、イミダゾリウム系４級アンモニウム塩の室温イオン性液体を用いることも可能である。
【００２９】
光電変換素子の漏液、電解質の揮発を低減する目的で、上記電解質組成物へゲル化剤、ポリマー、架橋モノマーなどを溶解させ、ゲル状電解質として使用することも可能である。ゲルマトリクスと電解質組成物との比率は、電解質組成物が多ければイオン導電率は高くなるが、機械的強度は低下する。また、逆に電解質組成物が少な過ぎると機械的強度は大きいがイオン導電率は低下するため、電解質組成物はゲル状電解質の５０〜９９ｗｔ％が望ましく、８０〜９７ｗｔ％がより好ましい。また、上記電解質と可塑剤とを用いてポリマーに溶解させ、可塑剤を揮発除去することで全固体型の光電変換素子を実現することも可能である。
【００３０】
光電変換素子の製造方法は特に限定されないが、例えば電解質組成物が液状、もしくは光電変換素子内部でゲル化させることが可能であり、導入前は液状の電解質組成物の場合、色素を担持させた半導体電極と対極とを向かい合わせ、これらの電極が互いに接しないように半導体電極が形成されていない基板部分を封止する。このとき、半導体電極と対極との隙間に特に制限はないが、通常１〜１００μｍであり、より好ましくは１〜５０μｍである。この電極間の距離が長すぎると、導電率の低下から光電流が減少してしまう。封止方法は特に制限されないが、対光性、絶縁性、防湿性を備えた材料が好ましく、種々の溶接法、エポキシ樹脂、紫外線硬化樹脂、アクリル系接着剤、ＥＶＡ（エチレンビニルアセテート） 、アイオノマー樹脂、セラミック、熱融着フィルムなどを用いることができる。また、電解質組成物の溶液を注液する注入口が必要であるが、色素を担持した半導体電極およびそれに対向する部分の対極上でなければ、注入口の場所は特に限定されない。注液方法に特に制限はないが、予め封止され、溶液の注入口を開けられた上記セルの内部に注液を行う方法が好ましい。この場合、注入口に溶液を数滴垂らし、毛細管現象により注液する方法が簡便である。また、必要に応じて減圧もしくは加熱下で注液の操作を行うこともできる。完全に溶液が注入された後、注入口に残った溶液を除去し、注入口を封止する。この封止方法にも特に制限はないが、必要であればガラス板やプラスチック基板などを封止剤で貼り付けて封止することもできる。また、ポリマーなどを用いたゲル状電解質、全固体型の電解質の場合、色素を担持した半導体電極上で電解質組成物と可塑剤とを含むポリマー溶液をキャスト法により揮発除去させる。可塑剤を完全に除去した後、上記方法と同様に封止を行う。この封止は真空シーラーなどを用いて、不活性ガス雰囲気下、もしくは減圧中で行うことが好ましい。封止を行った後、電解質を半導体微粒子層へ十分に含侵させるため、必要に応じて加熱、加圧の操作を行うことも可能である。
光電変換素子はその用途に応じて様々な形状で作製することが可能であり、その形状は特に限定されない。
光電変換素子は、最も典型的には、色素増感湿式光電変換素子（特に、色素増感湿式太陽電池）である。
【００３１】
金属酸化物膜上に上記のような中間膜を製膜し、この中間膜上に半導体微粒子からなる半導体電極を形成する上記の方法は、光電変換素子のみならず、金属酸化物膜上に半導体微粒子からなる半導体電極を形成する電子装置全般あるいは金属酸化物膜上に半導体微粒子層を形成する場合にも同様に適用することができるものである。
【００３２】
そこで、この発明の第３の発明は、
金属酸化物膜上に半導体微粒子からなる半導体電極を有する電子装置の製造方法において、
金属酸化物膜上に、
【化２７】

で示されるポリチオフェンまたはその誘導体と、
【化２８】

で示されるポリスチレンスルホン酸、ＲＳＯ_３ Ｈ（ただし、Ｒ＝アルキル、アリール）、Ｒ´ＯＳＯ_３ Ｈ（ただし、Ｒ´＝Ｈ、アルキル、アリール）、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ からなる群より選ばれた少なくとも一種類の化合物とからなる中間膜を製膜し、この中間膜上に半導体電極を形成するようにした
ことを特徴とするものである。
【００３３】
この発明の第４の発明は、
金属酸化物膜上に半導体微粒子からなる半導体電極を有する電子装置において、
金属酸化物膜上に、
【化２９】

で示されるポリチオフェンまたはその誘導体と、
【化３０】

で示されるポリスチレンスルホン酸、ＲＳＯ_３ Ｈ（ただし、Ｒ＝アルキル、アリール）、Ｒ´ＯＳＯ_３ Ｈ（ただし、Ｒ´＝Ｈ、アルキル、アリール）、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ からなる群より選ばれた少なくとも一種類の化合物とからなる中間膜を製膜し、この中間膜上に半導体電極を形成した
ことを特徴とするものである。
【００３４】
この発明の第５の発明は、
金属酸化物膜上に半導体微粒子層を形成するようにした半導体微粒子層の形成方法において、
金属酸化物膜上に、
【化３１】

で示されるポリチオフェンまたはその誘導体と、
【化３２】

で示されるポリスチレンスルホン酸、ＲＳＯ_３ Ｈ（ただし、Ｒ＝アルキル、アリール）、Ｒ´ＯＳＯ_３ Ｈ（ただし、Ｒ´＝Ｈ、アルキル、アリール）、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ からなる群より選ばれた少なくとも一種類の化合物とからなる中間膜を製膜し、この中間膜上に半導体微粒子層を形成するようにした
ことを特徴とするものである。
【００３５】
この発明の第６の発明は、
金属酸化物膜上に半導体微粒子層を形成した積層構造体において、
金属酸化物膜上に、
【化３３】

で示されるポリチオフェンまたはその誘導体と、
【化３４】

で示されるポリスチレンスルホン酸、ＲＳＯ_３ Ｈ（ただし、Ｒ＝アルキル、アリール）、Ｒ´ＯＳＯ_３ Ｈ（ただし、Ｒ´＝Ｈ、アルキル、アリール）、ＨＣｌ、ＨＣｌＯ_４ 、ＨＰＦ_６ 、ＨＢＦ_４ およびＨＩ_５ からなる群より選ばれた少なくとも一種類の化合物とからなる中間膜を製膜し、この中間膜上に半導体微粒子層を形成した
ことを特徴とするものである。
【００３６】
第１および第２の発明に関連して述べた上記のことは、その性質に反しない限り、第３〜第６の発明においても同様に成立する。電子装置には、光電変換素子のほか、半導体微粒子からなる半導体電極を用いる各種の半導体装置などが含まれる。
【００３７】
上述のように構成されたこの発明によれば、金属酸化物膜上にポリチオフェンまたはその誘導体とポリスチレンスルホン酸などとからなる中間膜を製膜し、この中間膜上に酸化チタン微粒子層などの半導体微粒子層を形成するようにしているため、金属酸化物膜に対するこの中間膜の付着性およびこの中間膜に対する半導体微粒子層の付着性とも極めて良好であることにより、この半導体微粒子層を金属酸化物膜上に直接形成する場合に比べて、半導体微粒子層の付着性の大幅な向上を図ることができる。また、強酸性の半導体微粒子分散液を用いて金属酸化物膜上に半導体微粒子層を形成する場合、この中間膜が強酸に対して保護層として働くことにより、金属酸化物膜の溶出を防止することができる。さらに、この中間膜は導電性高分子からなり導電性を有するため、半導体電極と金属酸化物膜との導通を良好に保つことができる。
【００３８】
【発明の実施の形態】
以下、この発明の一実施形態について図面を参照しながら説明する。なお、実施形態の全図において、同一または対応する部分には同一の符号を付す。
図１〜図５はこの発明の一実施形態による色素増感型湿式太陽電池の製造方法を示す。
【００３９】
この一実施形態においては、まず、図１に示すように、透明基板１１上にＩＴＯなどの金属酸化物からなる透明電極１２を形成したものを用意する。
次に、図２に示すように、この透明電極１２上にＰＥＤＯＴ／ＰＳＳ膜１３を製膜する。このＰＥＤＯＴ／ＰＳＳ膜１３の厚さは例えば３０〜４００ｎｍとする。このＰＥＤＯＴ／ＰＳＳ膜１３を製膜するには、例えば、ＰＥＤＯＴ／ＰＳＳ水溶液を透明電極１２上にスピンコートした後、これを加熱して水分を蒸発させ、固化する。
【００４０】
次に、図３に示すように、このＰＥＤＯＴ／ＰＳＳ膜１３上に、増感色素を担持した半導体微粒子層１４を形成する。この増感色素を担持した半導体微粒子層１４は例えば次のようにして形成することができる。すなわち、まず、半導体微粒子が分散されたコロイド溶液をスピンコートした後、透明基板１１の耐熱温度以下の温度、例えば１００〜１４０℃の温度で加熱することにより溶媒を蒸発させて乾燥を行う。これによって、半導体微粒子層１４が形成される。この後、この半導体微粒子層１４を色素溶液に浸漬するなどにより色素を担持させる。
【００４１】
一方、図４に示すように、透明基板１５上にＩＴＯなどの金属酸化物からなる透明電極１６を形成したものを用意し、この透明電極１６上に上記と同様にしてＰＥＤＯＴ／ＰＳＳ膜１７を製膜する。このＰＥＤＯＴ／ＰＳＳ膜１７の厚さは例えば３０〜４００ｎｍとする。この後、このＰＥＤＯＴ／ＰＳＳ膜１７上に対極として白金膜１８を製膜する。
【００４２】
次に、図５に示すように、透明電極１２、ＰＥＤＯＴ／ＰＳＳ膜１３および半導体微粒子層１４を形成した透明基板１１と透明電極１６、ＰＥＤＯＴ／ＰＳＳ膜１７および白金膜１８を形成した透明基板１５とを、半導体微粒子層１４と白金膜１８とが所定の間隔を持って互いに対向するように配置するとともに、所定の封止部材を用いて電解質層が封入される空間を作り、この空間に、予め形成された注液口から電解質層１９を注入する。その後、この注液口を塞ぐ。これによって、色素増感型湿式太陽電池が製造される。
【００４３】
次に、この色素増感型湿式太陽電池の動作について説明する。
図６に示すように、透明基板１１側からこの透明基板１１を透過して入射した光は、半導体微粒子層１４の表面に担持された増感色素を励起して電子を発生する。この電子は速やかに増感色素から半導体微粒子層１４の半導体微粒子に渡される。一方、電子を失った増感色素は、電解質層１９のイオンから電子を受け取り、電子を渡したイオンは、再び対極の白金膜１８で電子を受け取る。この一連の過程により、半導体微粒子層１４とＰＥＤＯＴ／ＰＳＳ膜１３を介して電気的に接続された透明電極１２と白金膜１８との間に起電力が発生する。このようにして光電変換が行われる。
【００４４】
以上のように、この一実施形態によれば、ＩＴＯなどの金属酸化物からなる透明電極１２上にまずＰＥＤＯＴ／ＰＳＳ膜１３を製膜した後、その上に半導体微粒子分散液を用いて半導体微粒子層１４を形成していることにより、透明電極１２上に半導体微粒子層１４を直接形成する場合に比べて、半導体微粒子層１４の付着性を大幅に向上させることができ、それによって半導体微粒子層１４は極めて剥がれにくくなり、割れも起こりにくくなる。また、強酸性の半導体微粒子分散液を用いて半導体微粒子層１４を形成する場合、ＰＥＤＯＴ／ＰＳＳ膜１３が透明電極１２の保護層として働くため、強酸による透明電極１２の溶出を防止することができる。また、半導体微粒子層１４が例えば酸化チタン微粒子層である場合、酸化チタンはｎ型半導体であるのに対し、ＰＥＤＯＴ／ＰＳＳ膜１３はｐ型半導体であり、このことからすると透明電極１２と半導体微粒子層１４との間にＰＥＤＯＴ／ＰＳＳ膜１３を挿入することはエネルギーダイアグラム的には不利に働くと考えられるにもかかわらず、実験結果によると、ＰＥＤＯＴ／ＰＳＳ膜１３を挿入することにより、かえって透明電極１２と半導体微粒子層１４との導通を良好に取ることができ、色素増感型湿式太陽電池の光電変換効率の大幅な向上を図ることができる。さらに、ＰＥＤＯＴ／ＰＳＳ膜１３は、上記のスピンコート法やローラーコート法などにより低温プロセスで容易に製膜することができる。
【００４５】
また、この一実施形態によれば、対極側についても、ＩＴＯなどの金属酸化物からなる透明電極１６上にまずＰＥＤＯＴ／ＰＳＳ膜１７を製膜した後、その上に対極として白金膜１８を製膜していることにより、透明電極１６上に白金膜１８を直接製膜する場合に比べて、白金膜１８の付着性を大幅に向上させることができ、それによって白金膜１８は極めて剥がれにくくなる。このため、対極としての白金膜１８の耐久性が大幅に向上し、ひいては色素増感型湿式太陽電池の耐久性、信頼性および寿命の大幅な向上を図ることができる。また、白金膜１８の下地はＰＥＤＯＴ／ＰＳＳ膜１７であるので、白金膜１８の異種金属による汚染の問題がない。さらに、上記のようにＰＥＤＯＴ／ＰＳＳ膜１７は導電性高分子であるため、透明電極１６と白金膜１８との電気的接触も良好に保つことができ、色素増感型湿式太陽電池の動作を良好に行うことができる。
【００４６】
さらに、透明基板１１、１５としてポリエチレンテレフタレート（ＰＥＴ）フィルムなどのフレキシブルな透明プラスチック基板を用いることにより、フレキシブルな色素増感型湿式太陽電池を実現することができ、ポータブル化や壁や窓に張るだけという色素増感型湿式太陽電池の利用場所の拡張および利便性の大幅な向上を図ることができる。
【００４７】
【実施例】
色素増感型湿式太陽電池の製造方法の実施例について説明する。
実施例１
まず、透明基板１１および透明電極１２として、厚さ１２０μｍのＰＥＴフィルム上に厚さ３００ｎｍのＩＴＯ膜を真空蒸着したものを準備する。このＩＴＯ付きＰＥＴフィルムのシート抵抗は１０〜３０Ω／□である。この後、このＩＴＯ付きＰＥＴフィルムを２５ｍｍ角にカットする。
【００４８】
次に、このＩＴＯ膜からなる透明電極１２の表面を順に純水中、イソプロパノール中にて１５分間超音波洗浄して脱脂した後、窒素気流下で乾燥する。
次に、このＩＴＯ膜からなる透明電極１２上に次のようにしてＰＥＤＯＴ／ＰＳＳ膜１３を製膜する。まず、透明電極１２を形成した透明基板１１、すなわちＩＴＯ付きＰＥＴフィルムをガラス基板上に固定し、ガラス基板ごとスピンコーターに設置する。次に、このＩＴＯ付きＰＥＴフィルム上にＰＥＤＯＴ／ＰＳＳの１．３ｗｔ％水溶液を展開し、最初の５秒間は毎分５００回転で、続く３０秒間は毎分５０００回転でスピンコートする。この後、このスピンコート後のＩＴＯ付きＰＥＴフィルムを１２０℃に加熱したホットプレート上に置き、そのまま３０分間乾燥させる。なお、非特許文献７ではＩＴＯがＰＥＤＯＴ／ＰＳＳ水溶液に長時間濡れたままで放置しておくと、ＩＴＯがＰＥＤＯＴ／ＰＳＳ水溶液の酸性で侵され、インジウムがＰＥＤＯＴ／ＰＳＳ中に拡散すると報告されているが、ここでは電気伝導度測定からＩＴＯからなる透明電極１２に大きな変化がないことが確認されている。
【００４９】
乾燥後、第一層としてＴｉ（Ｏ−ｉＰｒ）_４ の２％トルエン溶液を上記のＰＥＤＯＴ／ＰＳＳ水溶液と同条件でスピンコートし、１２０℃で３０分間乾燥を行った。続いて、非特許文献６の方法により得られる、酸化チタン濃度が１０％に調製された酸化チタンコロイド溶液をスピンコートし、１２０℃で３０分間乾燥する作業を５回繰り返した。このようにして、酸化チタン微粒子からなる半導体微粒子層１４を形成した。得られた半導体微粒子層１４の厚さは約３〜５μｍであった。
【００５０】
一方、透明基板１５および透明電極１６として、厚さ１２０μｍのＰＥＴフィルム上に厚さ３００ｎｍのＩＴＯ膜を真空蒸着したものを準備する。このＩＴＯ付きＰＥＴフィルムのシート抵抗は１０〜３０Ω／□である。この後、このＩＴＯ付きＰＥＴフィルムを２５ｍｍ角にカットする。次に、このＩＴＯ膜の表面を順に純水中、イソプロパノール中にて１５分間超音波洗浄して脱脂した後、窒素気流下で乾燥する。
【００５１】
次に、ＩＴＯ膜からなる透明電極１６上に上記と同様にしてＰＥＤＯＴ／ＰＳＳ膜１７を作製する。
次に、このＰＥＤＯＴ／ＰＳＳ膜１７上にスパッタリング法により白金膜１８を製膜する。この白金膜１８の厚さは４０ｎｍとした。
次に、酸化チタン微粒子からなる半導体微粒子層１４が形成されたＰＥＴフィルムをルテニウム色素（Ｒｕｔｈｅｎｉｕｍ（２，２’−ｂｉｐｙｒｉｄｙｌ−４，４’−ｄｉｃａｒｂｏｘｙｌａｔｅ）_２ （ＮＣＳ）_２ ）のエタノール溶液（ルテニウム色素（０．５ｍＭ）：デオキシコール酸（２０ｍＭ））に一晩浸漬し、半導体微粒子層１４に増感色素を担持させた後、これを取り出してエタノールですすぎ、すぐに太陽電池を組み立てる。
【００５２】
太陽電池の組み立ては次の手順で行った。まず、白金膜１８が形成された透明基板１５と酸化チタン微粒子からなる半導体微粒子層１４が形成された透明導電性基板１１とを、白金膜１８と半導体微粒子層１４とが幅５ｍｍのコの字型のポリテトラフルオロエチレン製スペーサー（厚さ０．３ｍｍ）を挟んで互いに対向するように保持し、その外周を厚さ３０μｍのＥＶＡフィルムとエポキシ樹脂とにより封止することで、電解質層を注入する空間を形成する。次に、この空間に予め形成された注液口から電解質層１９を注入する。電解質層１９としては、ＬｉＩ（０．５Ｍ）、ヨウ素（０．０５Ｍ）、ｔｅｒｔ−ブチルピリジン（０．５Ｍ）のプロピレンカーボネート／エチレンカーボネート（１／１）溶液を用いた。その後、注液口を塞ぐ。以上のようにして色素増感型湿式太陽電池を得た。
【００５３】
実施例２
実施例２では、酸化チタン微粒子からなる半導体微粒子層１４を以下のようにして形成すること以外は上記の実施例１と同様にして色素増感型湿式太陽電池を作製した。
すなわち、実施例２では、まず、非特許文献６の方法により得られる、酸化チタン濃度が１０％に調製された酸化チタンコロイド溶液（１００ｍＬ）にこのコロイド溶液中の酸化チタンと等量になるように粒子サイズがより大きいアナターゼ型酸化チタン粉末を混合し、これを容量２５０ｍＬのジルコニアポットに１００ｇのジルコニアビーズとともに入れ、３時間遊星型ボールミルで分散した。この後、この溶液からビーズを濾過して除き、白色の酸化チタン分散液を得た。
【００５４】
次に、ＰＥＤＯＴ／ＰＳＳ膜１３上に、上記の酸化チタン濃度が１０％に調製された酸化チタンコロイド溶液を１層スピンコートした後、上記のようにして得た酸化チタン分散液を３層スピンコートした。ただし、各スピンコート後に１２０℃で３０分間乾燥を行った。
【００５５】
比較例１
比較例１では、透明電極１２上にＰＥＤＯＴ／ＰＳＳ膜１３を製膜しないで酸化チタン微粒子からなる半導体微粒子層１４を形成し、透明電極１６上にＰＥＤＯＴ／ＰＳＳ膜１７を製膜しないで白金膜１８を形成すること以外は上記の実施例１と同様にして色素増感型湿式太陽電池を作製した。
【００５６】
比較例２
比較例２では、市販のアナターゼ型酸化チタンを用いて非特許文献３の方法により透明電極１２上に直接電着を行うことにより酸化チタン微粒子からなる半導体微粒子層１４を形成し、透明電極１６上にＰＥＤＯＴ／ＰＳＳ膜１７を製膜しないで白金膜１８を製膜すること以外は上記の実施例１と同様にして色素増感型湿式太陽電池を作製した。
【００５７】
実施例１、２および比較例１、２について、酸化チタン微粒子からなる半導体微粒子層１４の観察を行ったところ、ＰＥＤＯＴ／ＰＳＳ膜１３を製膜しないで半導体微粒子層１４を形成した比較例１の試料では全面に割れが発生し、一部剥がれも生じたが、ＰＥＤＯＴ／ＰＳＳ膜１３を製膜してから酸化チタン微粒子からなる半導体微粒子層１４を形成した実施例１、２の試料では割れも剥がれもない良好なものであった。電着により半導体微粒子層１４を形成した比較例２の試料では、白い膜状の半導体微粒子層１４が得られたが、その膜の状態および付着性は良好であった。また、ＰＥＤＯＴ／ＰＳＳ膜１３を製膜してから白金膜１８を製膜した実施例１、２の試料では、この白金膜１８についても剥がれがなかった。
【００５８】
図７および表１に、実施例１および比較例１、２の太陽電池特性の評価を行った結果を示す。ただし、光源としてソーラーシミュレーター（ＵＳＨＩＯ Ｏｐｔｉｃａｌ Ｍｏｄｕｌｅｘ、５００Ｗキセノンショートアークランプ、ＡＭ１．５（８３．２ｍＷ／ｃｍ^２ ））を用いて評価を行った。
【００５９】

【００６０】
図７および表１より、実施例１は比較例１と比べて明らかに良好な太陽電池特性を有しており、比較例２と比べても非常に良好な開放電圧、短絡電流密度および光電変換効率を示し、フィルファクターもほぼ同等であることが分かる。
実施例２については、実施例１よりさらに優れた太陽電池特性が得られた。これは、酸化チタンコロイド溶液に粒子サイズがより大きいアナターゼ型酸化チタン粉末を分散した高粒子濃度の半導体微粒子分散液を用いて半導体微粒子層１４を形成したことにより、アナターゼ型酸化チタン粉末を分散しない半導体微粒子分散液を用いて半導体微粒子層１４を形成した実施例１よりも、半導体微粒子層１４がポーラスな構造をしていることを反映したものと考えられる。
【００６１】
以上、この発明の一実施形態および実施例について具体的に説明したが、この発明は、上述の実施形態および実施例に限定されるものではなく、この発明の技術的思想に基づく各種の変形が可能である。
例えば、上述の実施形態および実施例において挙げた数値、構造、形状、材料、原料、プロセスなどはあくまでも例に過ぎず、必要に応じてこれらと異なる数値、構造、形状、材料、原料、プロセスなどを用いてもよい。
【００６２】
具体的には、例えば、上述の実施形態および実施例においては、半導体微粒子層１４を形成した後にこれを色素溶液に浸漬することによりその半導体微粒子に色素を担持させているが、半導体微粒子に予め色素が担持されたペーストを塗布するようにしてもよい。
【００６３】
【発明の効果】
以上説明したように、この発明によれば、金属酸化物膜上にポリチオフェンまたはその誘導体とポリスチレンスルホン酸などとからなる中間膜を製膜し、この中間膜上に半導体微粒子からなる半導体電極あるいは半導体微粒子層を形成するようにしていることにより、金属酸化物膜上に半導体微粒子からなる半導体電極あるいは半導体微粒子層をその金属酸化物膜の溶出を防止しつつ、しかも低温プロセスで良好に形成することができる。
【図面の簡単な説明】
【図１】この発明の一実施形態による色素増感型湿式太陽電池の製造方法を説明するための断面図である。
【図２】この発明の一実施形態による色素増感型湿式太陽電池の製造方法を説明するための断面図である。
【図３】この発明の一実施形態による色素増感型湿式太陽電池の製造方法を説明するための断面図である。
【図４】この発明の一実施形態による色素増感型湿式太陽電池の製造方法を説明するための断面図である。
【図５】この発明の一実施形態による色素増感型湿式太陽電池の製造方法を説明するための断面図である。
【図６】この発明の一実施形態による色素増感型湿式太陽電池の動作を説明するための断面図である。
【図７】この発明の一実施形態による色素増感型湿式太陽電池の特性の測定結果を示す略線図である。
【符号の説明】
１１、１５…透明基板、１２、１６…透明電極、１３、１７…ＰＥＤＯＴ／ＰＳＳ膜、１４…半導体微粒子層、１８…白金膜、１９…電解質層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a photoelectric conversion element, a method for manufacturing a photoelectric conversion element, an electronic device, an electronic device, a method for forming a semiconductor fine particle layer, and a laminated structure. For example, a wet solar cell using a semiconductor electrode made of semiconductor fine particles It is suitable for application to.
[0002]
[Prior art]
Dye-sensitized solar cells that sensitize semiconductors with large band gaps with dyes are promising as inexpensive solar cells that can replace conventional solar cells made of silicon and compound semiconductors, and are being actively studied (non- Patent Document 1).
[Non-patent document 1]
Nature, 353, p. 737 (1991)
[0003]
Previous work has focused primarily on maximizing cell efficiency. In a recent study, a 10% energy conversion efficiency was reported by Gretzel et al. (Non-Patent Document 2).
[Non-patent document 2]
J. Am. Chem. Soc. 114 (1993) 6382
[0004]
In order to achieve high efficiency, it is necessary to sufficiently absorb light energy, and a porous film made of nanoscale semiconductor fine particles is used in order to enlarge the semiconductor surface on which the dye is adsorbed. At present, anatase-type titanium oxide is widely used as a semiconductor, but in order to increase energy efficiency, it is necessary to make sufficient electrical contact between these fine particles, and a high-temperature treatment of firing (about 450 ° C.) is required. It is. The necessity of this firing process has been a bottleneck in producing a flexible solar cell. That is, the polymer material used for the film electrode can hardly withstand such a high temperature.
[0005]
Recently, research on flexible solar cells has been started with the aim of making the solar cells portable, expanding the use place where the solar cells are merely attached to walls and windows, and improving convenience. As a conventional method, a method in which an electric field is applied to an ITO (indium-tin composite oxide) electrode by using a liquid in which titanium oxide is dispersed in an organic solvent and electrodeposition is performed (Non-patent document 3). Pressure bonding method (Non-Patent Document 4), TiCl which is a raw material of titanium oxide₄, TiOSO₄, Ti (O-iPr)₄And then heating in an autoclave at 100 ° C. for 24 hours (Non-Patent Document 5). However, these require an electrodeposition apparatus, a large press machine, a large autoclave, and the like, and have a problem in productivity.
[Non-Patent Document 3]
Chem. Lett. 12 (2002) 1250
[Non-patent document 4]
Nano Lett. 2 (2001) 97
[Non-Patent Document 5]
Chem. Lett. 9 (2002) 874
[0006]
On the other hand, there is a report that a good film can be obtained at a drying temperature of 100 ° C. by applying a titanium oxide colloid solution containing no surfactant (Non-Patent Document 6). According to this method, it is considered that a titanium oxide fine particle layer can be formed on a film electrode using a polymer material.
[Non-Patent Document 6]
Langmuir, 16 (2000) 5626.
[0007]
A transparent conductive material coated with a liquid containing an organic conductive polymer compound and a p-type inorganic semiconductor has been proposed (Patent Document 1). Further, it has been proposed to coat PEDOT / PSS as a coating material for a conductive substrate such as ITO (Patent Document 2). Further, it has been proposed to coat PEDOT / PSS on a glass substrate on which ITO is formed (Patent Document 3).
[Patent Document 1]
JP-A-2002-93242
[Patent Document 2]
JP 2002-526801 A
[Patent Document 3]
JP 2002-508599 A
[0008]
Also, there is a report that if ITO is left wet for a long time in the PEDOT / PSS aqueous solution, the ITO is attacked by the acidity of the PEDOT / PSS aqueous solution and indium diffuses into the PEDOT / PSS (Non-Patent Document 7). ).
[Non-Patent Document 7]
Appl. Phys. Lett. 77 (2000) 2255
[0009]
[Problems to be solved by the invention]
However, according to the method of Non-Patent Document 6, when no surfactant is contained, the titanium oxide colloid solution is stable only under strong acidity (pH <2), and under these conditions, the ITO electrode on the coated side elutes. There was a problem that would. For this reason, a fluorine-doped SnO (FTO) electrode having excellent acid resistance is used, but it is difficult to form the FTO on a polymer material film. It is disadvantageous for use as an electrode. It is also conceivable to use a neutral titanium oxide fine particle dispersion liquid, but in this case, since the titanium oxide fine particles hardly bond to each other and no cross-linking occurs, only a very fragile film is obtained, and practical use is difficult. .
[0010]
Therefore, the problem to be solved by the present invention is to provide a photoelectric conversion device capable of forming a semiconductor electrode composed of semiconductor fine particles on a metal oxide film in a low-temperature process while preventing elution of the metal oxide film. An object of the present invention is to provide an element manufacturing method and a photoelectric conversion element.
[0011]
The problem to be solved by the present invention is, more generally, to form a semiconductor electrode composed of semiconductor fine particles on a metal oxide film satisfactorily by a low-temperature process while preventing elution of the metal oxide film. It is an object of the present invention to provide a method of manufacturing an electronic device and an electronic device that can perform the method.
[0012]
The problem to be solved by the present invention is, more generally, a semiconductor capable of forming a semiconductor fine particle layer on a metal oxide film while preventing the metal oxide film from being eluted and at the same time favorably forming the semiconductor fine particle layer by a low-temperature process. An object of the present invention is to provide a method for forming a fine particle layer and a laminated structure.
[0013]
[Means for Solving the Problems]
The present inventor conducted various experiments and studies to solve the above-mentioned problems of the prior art. As a result, when a semiconductor fine particle layer such as a titanium oxide fine particle layer is formed on a metal oxide film such as ITO, First, a film made of polyethylenedioxythiophene (PEDOT) / polystyrenesulfonic acid (PSS), which is a water-soluble conductive polymer (p-type semiconductor), is formed on the metal oxide film, and a titanium oxide fine particle dispersion is formed thereon. It has been found that the above problems can be solved at once by forming a semiconductor fine particle layer such as a titanium oxide fine particle layer using a semiconductor fine particle dispersion liquid. As a result of further study, more generally, a film composed of polythiophene or a derivative thereof and polystyrene sulfonic acid was formed on a metal oxide film, and a semiconductor fine particle layer such as a titanium oxide fine particle layer was formed thereon. It was concluded that a similar effect could be obtained.
The present invention has been made based on the above study.
[0014]
That is, in order to solve the above problems, the first invention of the present invention is:
In a method for manufacturing a photoelectric conversion element having a semiconductor electrode composed of semiconductor fine particles on a metal oxide film,
On the metal oxide film,
Embedded image

With a polythiophene or a derivative thereof,
Embedded image

Polystyrenesulfonic acid represented by the formula: RSO₃H (where R = alkyl, aryl), R'OSO₃H (R '= H, alkyl, aryl), HCl, HClO₄, HPF₆, HBF₄And HI₅An intermediate film made of at least one compound selected from the group consisting of was formed, and a semiconductor electrode was formed on the intermediate film.
It is characterized by the following.
[0015]
According to a second aspect of the present invention,
In a photoelectric conversion element having a semiconductor electrode composed of semiconductor fine particles on a metal oxide film,
On the metal oxide film,
Embedded image

With a polythiophene or a derivative thereof,
Embedded image

Polystyrenesulfonic acid represented by the formula: RSO₃H (where R = alkyl, aryl), R'OSO₃H (R '= H, alkyl, aryl), HCl, HClO₄, HPF₆, HBF₄And HI₅An intermediate film comprising at least one compound selected from the group consisting of was formed, and a semiconductor electrode was formed on the intermediate film.
It is characterized by the following.
[0016]
In the first and second inventions, polystyrene sulfonic acid, RSO₃H, R'OSO₃H, HCl, HClO₄, HPF₆, HBF₄And HI₅Becomes a dopant for polythiophene or a derivative thereof, and these compounds constitute a conductive polymer.
[0017]
The interlayer most typically comprises
Embedded image

Represented by polyethylene dioxythiophene,
Embedded image

, Ie, PEDOT / PSS. This interlayer most typically comprises
Embedded image

Represented by polyethylene dioxythiophene,
Embedded image

And a polystyrene sulfonate ion represented by
Embedded image

And an aqueous solution containing polystyrene sulfonic acid represented by the formula (1), and spin-coating this on a metal oxide film.
[0018]
Even if the thickness of the intermediate film is about several nm, it is possible to improve the adhesion to the underlying metal oxide film and the adhesion of the semiconductor fine particle layer to the intermediate film, but the metal oxide to a strong acid can be improved. From the viewpoint of enhancing the protective effect of the film, the thickness is preferably 15 nm or more, more preferably 30 nm or more, and still more preferably 60 nm or more. Although the upper limit of the thickness of the intermediate film does not essentially exist, it is preferably 500 nm or less, more preferably 400 nm or less, from the viewpoint of reducing the film formation cost. That is, the thickness of the intermediate film is preferably 15 nm or more and 500 nm or less, more preferably 30 nm or more and 400 nm or less, and still more preferably 60 nm or more and 400 nm or less.
The above-mentioned intermediate film can also be used for improving the adhesion of a metal film such as a platinum film serving as a counter electrode of a semiconductor electrode to a metal oxide film underlying the metal film.
[0019]
The metal oxide film is, for example, an In—Sn composite oxide, SnO₂(Fluorine-doped SnO₂(Including FTO)), TiO₂And at least one type of metal oxide selected from the group consisting of ZnO and typically used as a transparent electrode.
The metal oxide film is typically formed on a conductive or non-conductive transparent support substrate. The material of the transparent support substrate is not particularly limited, and various substrates can be used as long as they are transparent. Are preferred. As the transparent support substrate, specifically, a transparent inorganic substrate such as quartz and glass, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, polyvinylidene fluoride, tetraacetyl cellulose, brominated phenoxy , Aramids, polyimides, polystyrenes, polyarylates, polysulfones, polyolefins, and the like, but are not limited thereto. As the transparent support substrate, it is preferable to use a transparent plastic substrate typified by polyethylene terephthalate or the like in consideration of workability, lightness, flexibility, and the like. The thickness of the transparent support substrate is not particularly limited, and can be freely selected depending on the light transmittance, the shielding property between the inside and the outside of the photoelectric conversion element, and the like.
[0020]
As the material of the semiconductor fine particles constituting the semiconductor electrode, various compound semiconductors, compounds having a perovskite structure, and the like can be used in addition to elemental semiconductors represented by silicon. These semiconductors are preferably n-type semiconductors in which conduction band electrons serve as carriers under photoexcitation to give an anode current. These semiconductors are specifically exemplified by TiO.₂, ZnO, WO₃, Nb₂O₅, TiSrO₃, SnO₂Among these, TiO₂Especially anatase type TiO₂Is particularly preferred from the viewpoint of photocatalytic activity. This anatase type TiO₂May be a commercially available powder, sol, or slurry, or may be made to have a predetermined particle size by a known method such as hydrolysis of titanium oxide alkoxide. The type of semiconductor is not limited to these, and two or more of these semiconductors can be used in combination.
[0021]
Although there is no particular limitation on the particle diameter of the semiconductor fine particles, the average particle diameter of the primary particles is preferably from 1 to 200 nm, particularly preferably from 5 to 100 nm. It is also possible to mix semiconductor fine particles having an average particle diameter larger than the average particle diameter with the semiconductor fine particles having the average particle diameter, and to scatter incident light by the semiconductor fine particles having a larger average particle diameter to improve the quantum yield. is there. In this case, the average particle size of the semiconductor fine particles separately mixed is preferably 20 to 500 nm.
[0022]
The method for forming a semiconductor electrode composed of semiconductor fine particles is not particularly limited, but in consideration of physical properties, convenience, production costs, and the like, a wet film forming method is preferable, and a powder or sol of semiconductor fine particles is dissolved in a solvent such as water. A method of uniformly dispersing and applying on a transparent conductive substrate having a metal oxide film formed on a conductive or non-conductive transparent support substrate is preferable. The coating method is not particularly limited, and various known methods can be used.For example, spin coating, roller coating, dipping, spraying, wire bar, blade coating, gravure coating, and wet coating can be used. As a printing method, for example, various methods such as letterpress, offset, gravure, intaglio, rubber plate, screen printing, and the like can be used. When a commercially available powder is used as the semiconductor fine particles, it is preferable to eliminate secondary agglomeration of the particles, and it is preferable to grind the particles using a mortar or a ball mill at the time of preparing a coating solution. At this time, it is preferable to add acetylacetone, hydrochloric acid, nitric acid, a surfactant, a chelating agent, and the like in order to prevent the particles having undergone secondary aggregation from being aggregated again. Further, for the purpose of thickening, various thickeners such as a polymer such as polyethylene oxide and polyvinyl alcohol, and a cellulose-based thickener can also be added.
[0023]
The dye to be supported on the semiconductor fine particles is not particularly limited as long as it exhibits a sensitizing effect. Examples thereof include xanthene dyes such as rhodamine B, rose bengal, eosin, and erythrosine; cyanine dyes such as quinocyanine and cryptocyanine. Basic dyes such as phenosafuranine, cabrio blue, thiosine, and methylene blue; porphyrin compounds such as chlorophyll, zinc porphyrin, and magnesium porphyrin; other azo dyes; phthalocyanine compounds; coumarin compounds; Ru bipyridine complex compounds; anthraquinone dyes; Ring quinone dyes and the like can be mentioned. Among them, the ruthenium (Ru) bipyridine complex compound is particularly preferable because of its high quantum yield, but is not limited thereto, and may be used alone or in combination of two or more.
[0024]
The method for supporting the dye on the semiconductor fine particle layer is not particularly limited. For example, the dye may be alcohols, nitriles, nitromethane, halogenated hydrocarbons, ethers, dimethyl sulfoxide, amides, N-methylpyrrolidone, 1,3 -Dissolve in a solvent such as dimethylimidazolidinone, 3-methyloxazolidinone, esters, carbonates, ketones, hydrocarbons, and water, and immerse the semiconductor fine particle layer therein, or apply a dye solution to the semiconductor fine particle layer. The method of applying is common. In this case, the charged amount of the dye molecules per one semiconductor fine particle is preferably 1 to 1000 molecules, and more preferably 1 to 100 molecules. When the dye molecules are carried in a large excess with respect to the semiconductor fine particles, electrons excited by light energy are not injected into the semiconductor fine particles and reduce the electrolyte, thereby causing energy loss. Therefore, the dye molecules are ideally adsorbed on the semiconductor fine particles in the form of a single molecule, and the temperature and pressure at which the dye molecules are supported can be changed as necessary. A carboxylic acid such as deoxycholic acid may be added for the purpose of reducing the association between the dyes. Also, an ultraviolet absorber can be used in combination.
[0025]
For the purpose of promoting the removal of the excessively adsorbed dye, the surface of the semiconductor fine particle layer may be treated with amines after the dye is adsorbed. Examples of the amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine and the like. When these are liquid, they may be used as they are or may be used by dissolving them in an organic solvent.
[0026]
As the counter electrode, any material can be used as long as it is a conductive material. However, an insulating material can also be used if a conductive layer is provided on the side facing the semiconductor electrode. However, it is preferable to use a material that is electrochemically stable as the electrode material, and specifically, it is preferable to use platinum, gold, a conductive polymer, carbon, or the like. Further, for the purpose of improving the catalytic effect of oxidation-reduction, it is preferable that the surface facing the semiconductor layer has a fine structure and an increased surface area. It is desired to be in a porous state. The platinum black state can be formed by anodic oxidation of platinum, chloroplatinic acid treatment, and the like, and the carbon in a porous state can be formed by sintering carbon fine particles, sintering an organic polymer, or the like.
[0027]
The electrolyte is iodine (I₂) And metal iodide or organic iodide, bromine (Br)₂) And metal bromide or organic bromide, metal complexes such as ferrocyanate / ferricyanate and ferrocene / ferricinium ions, sodium polysulfide, sulfur compounds such as alkylthiol / alkyldisulfide, viologen dyes, Hydroquinone / quinone and the like can be used. As the cation of the metal compound, Li, Na, K, Mg, Ca, Cs and the like, and as the cation of the organic compound, quaternary ammonium compounds such as tetraalkylammoniums, pyridiniums and imidazoliums are preferable. The present invention is not limited to these, and two or more of them can be used in combination. Among them, I₂An electrolyte which is a combination of a quaternary ammonium compound such as LiI, NaI or imidazolium iodide is preferred. The concentration of the electrolyte salt is preferably 0.05 to 5 M, more preferably 0.2 to 1 M, based on the solvent. I₂And Br₂Is preferably 0.0005 to 1M, more preferably 0.0001 to 0.1M. Further, various additives such as 4-tert-butylpyridine and carboxylic acid can be added for the purpose of improving the open-circuit voltage and the short-circuit current.
[0028]
Water, alcohols, ethers, esters, carbonates, lactones, carboxylic esters, phosphate triesters, heterocyclic compounds, nitriles, ketones, amides as solvents constituting the above electrolyte composition , Nitromethane, halogenated hydrocarbons, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, hydrocarbons, and the like, but are not limited thereto. They can be used alone or in combination of two or more. It is also possible to use a room temperature ionic liquid of a tetraalkyl-based, pyridinium-based or imidazolium-based quaternary ammonium salt as a solvent.
[0029]
For the purpose of reducing leakage of the photoelectric conversion element and volatilization of the electrolyte, it is also possible to dissolve a gelling agent, a polymer, a crosslinking monomer and the like in the above-mentioned electrolyte composition and use it as a gel electrolyte. As for the ratio between the gel matrix and the electrolyte composition, the more the electrolyte composition, the higher the ionic conductivity, but the lower the mechanical strength. Conversely, if the amount of the electrolyte composition is too small, the mechanical strength is large but the ionic conductivity is lowered. Therefore, the electrolyte composition is desirably 50 to 99 wt% of the gel electrolyte, and more preferably 80 to 97 wt%. Further, it is also possible to realize an all-solid-state photoelectric conversion element by dissolving in a polymer using the above-mentioned electrolyte and a plasticizer and volatilizing and removing the plasticizer.
[0030]
The method for producing the photoelectric conversion element is not particularly limited, for example, the electrolyte composition is liquid, or it is possible to gel inside the photoelectric conversion element, and before the introduction, in the case of a liquid electrolyte composition, the dye was carried. The semiconductor electrode and the counter electrode face each other, and a portion of the substrate where the semiconductor electrode is not formed is sealed so that these electrodes do not contact each other. At this time, the gap between the semiconductor electrode and the counter electrode is not particularly limited, but is usually 1 to 100 μm, and more preferably 1 to 50 μm. If the distance between the electrodes is too long, the photocurrent will decrease due to the decrease in conductivity. Although the sealing method is not particularly limited, a material having light-proofing properties, insulation property, and moisture-proofing property is preferable. Various welding methods, epoxy resin, ultraviolet curable resin, acrylic adhesive, EVA (ethylene vinyl acetate), ionomer Resins, ceramics, heat sealing films and the like can be used. In addition, an inlet for injecting the solution of the electrolyte composition is required, but the location of the inlet is not particularly limited as long as it is not on the counter electrode of the semiconductor electrode supporting the dye and the portion facing the semiconductor electrode. There is no particular limitation on the method of injecting the liquid, but a method of injecting the liquid into the above-mentioned cell, which is sealed in advance and has an opening for injecting the solution, is preferable. In this case, a simple method is to drop several drops of the solution at the injection port and inject the solution by capillary action. The injection operation may be performed under reduced pressure or under heating, if necessary. After the solution is completely injected, the solution remaining in the inlet is removed and the inlet is sealed. Although there is no particular limitation on the sealing method, a glass plate, a plastic substrate, or the like can be attached and sealed with a sealing agent if necessary. In the case of a gel electrolyte using a polymer or the like or an all-solid electrolyte, a polymer solution containing an electrolyte composition and a plasticizer is volatilized and removed by a casting method on a semiconductor electrode supporting a dye. After completely removing the plasticizer, sealing is performed in the same manner as in the above method. This sealing is preferably performed using a vacuum sealer or the like under an inert gas atmosphere or under reduced pressure. After the sealing, heating and pressurizing operations can be performed as necessary in order to sufficiently impregnate the semiconductor fine particle layer with the electrolyte.
The photoelectric conversion element can be manufactured in various shapes depending on its use, and the shape is not particularly limited.
The photoelectric conversion element is most typically a dye-sensitized wet-type photoelectric conversion element (particularly, a dye-sensitized wet-type solar cell).
[0031]
The above-described method of forming an intermediate film as described above on a metal oxide film and forming a semiconductor electrode composed of semiconductor fine particles on the intermediate film is not limited to a photoelectric conversion element, and a method of forming a semiconductor electrode on a metal oxide film. The present invention can be similarly applied to general electronic devices for forming a semiconductor electrode made of fine particles or to a case where a semiconductor fine particle layer is formed on a metal oxide film.
[0032]
Therefore, a third invention of the present invention is:
In a method for manufacturing an electronic device having a semiconductor electrode composed of semiconductor fine particles on a metal oxide film,
On the metal oxide film,
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With a polythiophene or a derivative thereof,
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Polystyrenesulfonic acid represented by the formula: RSO₃H (where R = alkyl, aryl), R'OSO₃H (R '= H, alkyl, aryl), HCl, HClO₄, HPF₆, HBF₄And HI₅An intermediate film made of at least one compound selected from the group consisting of was formed, and a semiconductor electrode was formed on the intermediate film.
It is characterized by the following.
[0033]
According to a fourth aspect of the present invention,
In an electronic device having a semiconductor electrode made of semiconductor fine particles on a metal oxide film,
On the metal oxide film,
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With a polythiophene or a derivative thereof,
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Polystyrenesulfonic acid represented by the formula: RSO₃H (where R = alkyl, aryl), R'OSO₃H (R '= H, alkyl, aryl), HCl, HClO₄, HPF₆, HBF₄And HI₅An intermediate film comprising at least one compound selected from the group consisting of was formed, and a semiconductor electrode was formed on the intermediate film.
It is characterized by the following.
[0034]
According to a fifth aspect of the present invention,
In a method for forming a semiconductor fine particle layer in which a semiconductor fine particle layer is formed on a metal oxide film,
On the metal oxide film,
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With a polythiophene or a derivative thereof,
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Polystyrenesulfonic acid represented by the formula: RSO₃H (where R = alkyl, aryl), R'OSO₃H (R '= H, alkyl, aryl), HCl, HClO₄, HPF₆, HBF₄And HI₅An intermediate film made of at least one compound selected from the group consisting of was formed, and a semiconductor fine particle layer was formed on the intermediate film.
It is characterized by the following.
[0035]
According to a sixth aspect of the present invention,
In a laminated structure in which a semiconductor fine particle layer is formed on a metal oxide film,
On the metal oxide film,
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With a polythiophene or a derivative thereof,
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Polystyrenesulfonic acid represented by the formula: RSO₃H (where R = alkyl, aryl), R'OSO₃H (R '= H, alkyl, aryl), HCl, HClO₄, HPF₆, HBF₄And HI₅An intermediate film comprising at least one compound selected from the group consisting of was formed, and a semiconductor fine particle layer was formed on the intermediate film.
It is characterized by the following.
[0036]
The above described in connection with the first and second inventions is similarly established in the third to sixth inventions as long as they do not contradict their properties. The electronic device includes, in addition to the photoelectric conversion element, various semiconductor devices using a semiconductor electrode made of semiconductor fine particles.
[0037]
According to the present invention configured as described above, an intermediate film made of polythiophene or a derivative thereof and polystyrene sulfonic acid is formed on a metal oxide film, and a semiconductor such as a titanium oxide fine particle layer is formed on the intermediate film. Since the fine particle layer is formed, the adhesion of the intermediate film to the metal oxide film and the adhesion of the semiconductor fine particle layer to the intermediate film are extremely good. Compared with the case where the semiconductor fine particle layer is formed directly on the semiconductor fine particle layer, the adhesion of the semiconductor fine particle layer can be greatly improved. Further, when a semiconductor fine particle layer is formed on a metal oxide film using a strongly acidic semiconductor fine particle dispersion, this intermediate film acts as a protective layer against a strong acid, thereby preventing elution of the metal oxide film. be able to. Further, since the intermediate film is made of a conductive polymer and has conductivity, good conduction between the semiconductor electrode and the metal oxide film can be maintained.
[0038]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In all the drawings of the embodiments, the same or corresponding portions are denoted by the same reference numerals.
1 to 5 show a method of manufacturing a dye-sensitized wet solar cell according to one embodiment of the present invention.
[0039]
In this embodiment, first, as shown in FIG. 1, a transparent substrate 11 on which a transparent electrode 12 made of a metal oxide such as ITO is formed is prepared.
Next, as shown in FIG. 2, a PEDOT / PSS film 13 is formed on the transparent electrode 12. The thickness of the PEDOT / PSS film 13 is, for example, 30 to 400 nm. In order to form the PEDOT / PSS film 13, for example, a PEDOT / PSS aqueous solution is spin-coated on the transparent electrode 12, and then heated to evaporate moisture and solidify.
[0040]
Next, as shown in FIG. 3, a semiconductor fine particle layer 14 carrying a sensitizing dye is formed on the PEDOT / PSS film 13. The semiconductor fine particle layer 14 carrying the sensitizing dye can be formed, for example, as follows. That is, first, after spin-coating a colloidal solution in which semiconductor fine particles are dispersed, the transparent substrate 11 is heated at a temperature lower than the heat-resistant temperature, for example, at a temperature of 100 to 140 ° C. to evaporate the solvent and dry. Thereby, the semiconductor fine particle layer 14 is formed. Thereafter, the dye is carried by dipping the semiconductor fine particle layer 14 in a dye solution or the like.
[0041]
On the other hand, as shown in FIG. 4, a transparent electrode 16 made of a metal oxide such as ITO is formed on a transparent substrate 15, and a PEDOT / PSS film 17 is formed on the transparent electrode 16 in the same manner as described above. Form a film. The thickness of the PEDOT / PSS film 17 is, for example, 30 to 400 nm. Thereafter, a platinum film 18 is formed on the PEDOT / PSS film 17 as a counter electrode.
[0042]
Next, as shown in FIG. 5, a transparent substrate 11 on which a transparent electrode 12, a PEDOT / PSS film 13 and a semiconductor fine particle layer 14 are formed, and a transparent substrate 15 on which a transparent electrode 16, a PEDOT / PSS film 17 and a platinum film 18 are formed. Are arranged so that the semiconductor fine particle layer 14 and the platinum film 18 face each other at a predetermined interval, and a space for enclosing the electrolyte layer is formed by using a predetermined sealing member. The electrolyte layer 19 is injected from a previously formed liquid inlet. Thereafter, the injection port is closed. As a result, a dye-sensitized wet solar cell is manufactured.
[0043]
Next, the operation of the dye-sensitized wet solar cell will be described.
As shown in FIG. 6, light transmitted through the transparent substrate 11 from the transparent substrate 11 side and incident thereon excites a sensitizing dye carried on the surface of the semiconductor fine particle layer 14 to generate electrons. The electrons are quickly transferred from the sensitizing dye to the semiconductor fine particles of the semiconductor fine particle layer 14. On the other hand, the sensitizing dye that has lost the electrons receives electrons from the ions of the electrolyte layer 19, and the ions that have passed the electrons receive the electrons again at the platinum film 18 of the counter electrode. Through this series of processes, an electromotive force is generated between the transparent electrode 12 and the platinum film 18, which are electrically connected via the semiconductor fine particle layer 14 and the PEDOT / PSS film 13. Thus, photoelectric conversion is performed.
[0044]
As described above, according to this embodiment, the PEDOT / PSS film 13 is first formed on the transparent electrode 12 made of a metal oxide such as ITO, and then the semiconductor fine particles are formed thereon using the semiconductor fine particle dispersion. By forming the layer 14, the adhesion of the semiconductor fine particle layer 14 can be greatly improved as compared with the case where the semiconductor fine particle layer 14 is directly formed on the transparent electrode 12. Is extremely difficult to peel off and cracks are unlikely to occur. When the semiconductor fine particle layer 14 is formed using a strongly acidic semiconductor fine particle dispersion, the PEDOT / PSS film 13 functions as a protective layer for the transparent electrode 12, so that elution of the transparent electrode 12 due to a strong acid can be prevented. . When the semiconductor fine particle layer 14 is, for example, a titanium oxide fine particle layer, the titanium oxide is an n-type semiconductor, whereas the PEDOT / PSS film 13 is a p-type semiconductor. Although the insertion of the PEDOT / PSS film 13 between the layer 14 and the layer 14 is considered to be disadvantageous in terms of an energy diagram, according to the experimental results, the insertion of the PEDOT / PSS film 13 on the contrary makes it transparent. The connection between the electrode 12 and the semiconductor fine particle layer 14 can be made good, and the photoelectric conversion efficiency of the dye-sensitized wet solar cell can be greatly improved. Further, the PEDOT / PSS film 13 can be easily formed by a low-temperature process by the spin coating method, the roller coating method, or the like.
[0045]
Further, according to this embodiment, on the counter electrode side, first, a PEDOT / PSS film 17 is formed on the transparent electrode 16 made of a metal oxide such as ITO, and then a platinum film 18 is formed thereon as a counter electrode. By forming the film, the adhesion of the platinum film 18 can be greatly improved as compared with the case where the platinum film 18 is formed directly on the transparent electrode 16, whereby the platinum film 18 is extremely hard to peel off. . Therefore, the durability of the platinum film 18 as a counter electrode is greatly improved, and the durability, reliability, and life of the dye-sensitized wet solar cell can be significantly improved. In addition, since the PEDOT / PSS film 17 is provided under the platinum film 18, there is no problem of contamination of the platinum film 18 by different kinds of metals. Further, since the PEDOT / PSS film 17 is a conductive polymer as described above, the electrical contact between the transparent electrode 16 and the platinum film 18 can be kept good, and the operation of the dye-sensitized wet solar cell can be improved. Can be performed well.
[0046]
Furthermore, by using a flexible transparent plastic substrate such as a polyethylene terephthalate (PET) film as the transparent substrates 11 and 15, a flexible dye-sensitized wet-type solar cell can be realized, which can be made portable or installed on a wall or a window. The use of the dye-sensitized wet-type solar cell can be expanded, and the convenience can be greatly improved.
[0047]
【Example】
An example of a method for manufacturing a dye-sensitized wet solar cell will be described.
Example 1
First, a transparent substrate 11 and a transparent electrode 12 prepared by vacuum-depositing a 300-nm-thick ITO film on a 120-μm-thick PET film are prepared. The sheet resistance of this PET film with ITO is 10 to 30 Ω / □. Thereafter, the PET film with ITO is cut into a 25 mm square.
[0048]
Next, the surface of the transparent electrode 12 made of the ITO film is sequentially degreased by ultrasonic cleaning in isopropanol in pure water for 15 minutes, and then dried under a nitrogen stream.
Next, a PEDOT / PSS film 13 is formed on the transparent electrode 12 made of the ITO film as follows. First, a transparent substrate 11 on which a transparent electrode 12 is formed, that is, a PET film with ITO is fixed on a glass substrate, and the entire glass substrate is placed on a spin coater. Next, a 1.3 wt% aqueous solution of PEDOT / PSS is spread on the ITO-attached PET film, and spin-coated at 500 revolutions per minute for the first 5 seconds and 5000 revolutions per minute for the next 30 seconds. Thereafter, the spin-coated PET film with ITO is placed on a hot plate heated to 120 ° C., and dried as it is for 30 minutes. Non-Patent Document 7 reports that if ITO is left wet for a long time in the PEDOT / PSS aqueous solution, the ITO is attacked by the acidity of the PEDOT / PSS aqueous solution, and indium diffuses into the PEDOT / PSS. However, here, it has been confirmed from the electrical conductivity measurement that there is no significant change in the transparent electrode 12 made of ITO.
[0049]
After drying, Ti (O-iPr) is used as the first layer.₄Was spin-coated with the above-mentioned aqueous solution of PEDOT / PSS under the same conditions, and dried at 120 ° C. for 30 minutes. Subsequently, the operation of spin-coating a titanium oxide colloid solution having a titanium oxide concentration adjusted to 10% obtained by the method of Non-Patent Document 6 and drying at 120 ° C. for 30 minutes was repeated five times. Thus, the semiconductor fine particle layer 14 composed of the titanium oxide fine particles was formed. The thickness of the obtained semiconductor fine particle layer 14 was about 3 to 5 μm.
[0050]
On the other hand, a transparent substrate 15 and a transparent electrode 16 prepared by vacuum-depositing a 300-nm-thick ITO film on a 120-μm-thick PET film are prepared. The sheet resistance of this PET film with ITO is 10 to 30 Ω / □. Thereafter, the PET film with ITO is cut into a 25 mm square. Next, the surface of the ITO film is sequentially degreased by ultrasonic cleaning in isopropanol for 15 minutes in pure water, and then dried under a nitrogen stream.
[0051]
Next, a PEDOT / PSS film 17 is formed on the transparent electrode 16 made of an ITO film in the same manner as described above.
Next, a platinum film 18 is formed on the PEDOT / PSS film 17 by a sputtering method. The thickness of the platinum film 18 was 40 nm.
Next, the PET film on which the semiconductor fine particle layer 14 made of titanium oxide fine particles is formed is coated with a ruthenium dye (Ruthenium (2,2'-bipyridyl-4,4'-dicarboxylate)).₂(NCS)₂) Is immersed in an ethanol solution (ruthenium dye (0.5 mM): deoxycholic acid (20 mM)) overnight to carry the sensitizing dye on the semiconductor fine particle layer 14, taken out, rinsed with ethanol, and immediately Assemble the solar cells.
[0052]
The solar cell was assembled in the following procedure. First, a transparent substrate 15 on which a platinum film 18 is formed and a transparent conductive substrate 11 on which a semiconductor fine particle layer 14 made of titanium oxide fine particles are formed are formed by forming the platinum film 18 and the semiconductor fine particle layer 14 into a U-shape having a width of 5 mm. The electrolyte layer is injected by holding the mold so that it faces each other with a polytetrafluoroethylene spacer (thickness: 0.3 mm) interposed therebetween, and sealing the outer periphery with a 30 μm thick EVA film and epoxy resin. To form a space for Next, the electrolyte layer 19 is injected into the space from a liquid injection port formed in advance. As the electrolyte layer 19, a propylene carbonate / ethylene carbonate (1/1) solution of LiI (0.5M), iodine (0.05M), and tert-butylpyridine (0.5M) was used. Thereafter, the injection port is closed. Thus, a dye-sensitized wet solar cell was obtained.
[0053]
Example 2
In Example 2, a dye-sensitized wet solar cell was manufactured in the same manner as in Example 1 except that the semiconductor fine particle layer 14 made of titanium oxide fine particles was formed as follows.
That is, in Example 2, first, a titanium oxide colloid solution (100 mL) having a titanium oxide concentration adjusted to 10% obtained by the method of Non-Patent Document 6 was prepared to have an equivalent amount to the titanium oxide in this colloid solution. Was mixed with 100 g of zirconia beads in a 250 ml zirconia pot, and dispersed in a planetary ball mill for 3 hours. Thereafter, the beads were removed from the solution by filtration to obtain a white titanium oxide dispersion.
[0054]
Next, on the PEDOT / PSS film 13, one layer of the titanium oxide colloid solution having the above-mentioned titanium oxide concentration adjusted to 10% is spin-coated, and then the titanium oxide dispersion obtained as described above is spin-coated with three layers. Coated. However, drying was performed at 120 ° C. for 30 minutes after each spin coating.
[0055]
Comparative Example 1
In Comparative Example 1, a semiconductor fine particle layer 14 made of titanium oxide fine particles was formed on the transparent electrode 12 without forming the PEDOT / PSS film 13, and a platinum film was formed on the transparent electrode 16 without forming the PEDOT / PSS film 17. A dye-sensitized wet solar cell was manufactured in the same manner as in Example 1 except that No. 18 was formed.
[0056]
Comparative Example 2
In Comparative Example 2, a semiconductor fine particle layer 14 composed of titanium oxide fine particles was formed by performing electrodeposition directly on the transparent electrode 12 according to the method of Non-Patent Document 3 using commercially available anatase type titanium oxide. A dye-sensitized wet solar cell was manufactured in the same manner as in Example 1 except that the platinum film 18 was formed without forming the PEDOT / PSS film 17.
[0057]
When the semiconductor fine particle layer 14 made of titanium oxide fine particles was observed in Examples 1 and 2 and Comparative Examples 1 and 2, the semiconductor fine particle layer 14 was formed without forming the PEDOT / PSS film 13. Although cracks occurred on the entire surface of the sample and partially peeled off, the samples of Examples 1 and 2 in which the semiconductor fine particle layer 14 made of titanium oxide fine particles was formed after the PEDOT / PSS film 13 was formed, It was good without peeling. In the sample of Comparative Example 2 in which the semiconductor fine particle layer 14 was formed by electrodeposition, a white film-like semiconductor fine particle layer 14 was obtained, but the state and adhesion of the film were good. In the samples of Examples 1 and 2 in which the PEDOT / PSS film 13 was formed and then the platinum film 18 was formed, the platinum film 18 did not peel off.
[0058]
FIG. 7 and Table 1 show the results of evaluation of the solar cell characteristics of Example 1 and Comparative Examples 1 and 2. However, as a light source, a solar simulator (USHIO Optical Module, 500 W xenon short arc lamp, AM1.5 (83.2 mW / cm²)).
[0059]

[0060]
7 and Table 1, Example 1 has clearly better solar cell characteristics as compared with Comparative Example 1, and has very good open-circuit voltage, short-circuit current density, and photoelectric conversion as compared with Comparative Example 2. It shows the efficiency and the fill factor is almost the same.
In Example 2, more excellent solar cell characteristics than in Example 1 were obtained. This is because the semiconductor fine particle layer 14 is formed by using a semiconductor fine particle dispersion having a high particle concentration in which an anatase type titanium oxide powder having a larger particle size is dispersed in a titanium oxide colloid solution, so that the anatase type titanium oxide powder is not dispersed. This is considered to reflect that the semiconductor fine particle layer 14 has a porous structure as compared with Example 1 in which the semiconductor fine particle layer 14 was formed using the semiconductor fine particle dispersion.
[0061]
As mentioned above, although one Embodiment and Example of this invention were concretely demonstrated, this invention is not limited to said Embodiment and Example, Various deformation | transformation based on the technical idea of this invention is possible. It is possible.
For example, the numerical values, structures, shapes, materials, raw materials, processes, and the like listed in the above-described embodiments and examples are merely examples, and different numerical values, structures, shapes, materials, raw materials, processes, and the like may be used as necessary. May be used.
[0062]
Specifically, for example, in the above embodiments and examples, the semiconductor fine particles layer 14 is formed and then immersed in a dye solution to carry the dye on the semiconductor fine particles. A paste carrying a dye may be applied.
[0063]
【The invention's effect】
As described above, according to the present invention, an intermediate film made of polythiophene or a derivative thereof and polystyrene sulfonic acid is formed on a metal oxide film, and a semiconductor electrode or a semiconductor made of semiconductor fine particles is formed on the intermediate film. By forming the fine particle layer, it is possible to form a semiconductor electrode or a semiconductor fine particle layer composed of semiconductor fine particles on the metal oxide film while preventing the metal oxide film from being eluted and to form a good low-temperature process. Can be.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining a method for manufacturing a dye-sensitized wet solar cell according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view for explaining a method of manufacturing a dye-sensitized wet solar cell according to one embodiment of the present invention.
FIG. 3 is a cross-sectional view illustrating a method for manufacturing a dye-sensitized wet solar cell according to an embodiment of the present invention.
FIG. 4 is a cross-sectional view illustrating a method for manufacturing a dye-sensitized wet solar cell according to an embodiment of the present invention.
FIG. 5 is a cross-sectional view for explaining a method of manufacturing a dye-sensitized wet solar cell according to an embodiment of the present invention.
FIG. 6 is a cross-sectional view for explaining the operation of the dye-sensitized wet solar cell according to one embodiment of the present invention.
FIG. 7 is a schematic diagram illustrating measurement results of characteristics of a dye-sensitized wet solar cell according to an embodiment of the present invention.
[Explanation of symbols]
11, 15: transparent substrate, 12, 16: transparent electrode, 13, 17: PEDOT / PSS film, 14: semiconductor fine particle layer, 18: platinum film, 19: electrolyte layer

Claims (13)

In a method for manufacturing a photoelectric conversion element having a semiconductor electrode composed of semiconductor fine particles on a metal oxide film,
On the metal oxide film,

With a polythiophene or a derivative thereof,

, RSO ₃ H (where R = alkyl, aryl), R′OSO ₃ H (where R ′ = H, alkyl, aryl), HCl, HClO ₄ , HPF ₆ , HBF ₄ and HI _{5. A} method for manufacturing a photoelectric conversion element, comprising forming an intermediate film comprising at least one compound selected from the group consisting of No. ₅ and forming the semiconductor electrode on the intermediate film. The interlayer is

Represented by polyethylene dioxythiophene,

2. The method for producing a photoelectric conversion element according to claim 1, comprising polystyrenesulfonic acid represented by the formula: The above intermediate film

Represented by polyethylene dioxythiophene,

And a polystyrene sulfonate ion represented by

2. The method for producing a photoelectric conversion element according to claim 1, wherein the film is formed using an aqueous solution containing polystyrene sulfonic acid represented by the formula: The metal oxide film is In-Sn complex oxide, a photoelectric conversion element according to claim 1, characterized in that it consists of at least one metal oxide selected from the group consisting of SnO _2, TiO ₂ and ZnO Production method. 2. The method according to claim 1, wherein the metal oxide film is formed on a transparent plastic substrate. 2. The method according to claim 1, wherein the semiconductor electrode is formed using a strongly acidic semiconductor fine particle dispersion. The method according to claim 1, wherein the semiconductor electrode is formed at a temperature of 100 ° C. or more and 140 ° C. or less. The method according to claim 1, wherein the photoelectric conversion element is a wet solar cell. In a photoelectric conversion element having a semiconductor electrode composed of semiconductor fine particles on a metal oxide film,
On the metal oxide film,

With a polythiophene or a derivative thereof,

, RSO ₃ H (where R = alkyl, aryl), R′OSO ₃ H (where R ′ = H, alkyl, aryl), HCl, HClO ₄ , HPF ₆ , HBF ₄ and HI _{5. A} photoelectric conversion element comprising: forming an intermediate film made of at least one compound selected from the group consisting of No. 5; and forming the semiconductor electrode on the intermediate film. In a method for manufacturing an electronic device having a semiconductor electrode composed of semiconductor fine particles on a metal oxide film,
On the metal oxide film,

With a polythiophene or a derivative thereof,

, RSO ₃ H (where R = alkyl, aryl), R′OSO ₃ H (where R ′ = H, alkyl, aryl), HCl, HClO ₄ , HPF ₆ , HBF ₄ and HI _5. An electronic device manufacturing method, comprising forming an intermediate film made of at least one compound selected from the group consisting of No. ₅ and forming the semiconductor electrode on the intermediate film. In an electronic device having a semiconductor electrode made of semiconductor fine particles on a metal oxide film,
On the metal oxide film,

With a polythiophene or a derivative thereof,

, RSO ₃ H (where R = alkyl, aryl), R′OSO ₃ H (where R ′ = H, alkyl, aryl), HCl, HClO ₄ , HPF ₆ , HBF ₄ and HI to form a film of the intermediate layer comprising at least one compound selected from the group consisting of _5, the electronic apparatus characterized by the formation of the semiconductor electrode on the intermediate layer. In a method for forming a semiconductor fine particle layer in which a semiconductor fine particle layer is formed on a metal oxide film,
On the metal oxide film,

With a polythiophene or a derivative thereof,

, RSO ₃ H (where R = alkyl, aryl), R′OSO ₃ H (where R ′ = H, alkyl, aryl), HCl, HClO ₄ , HPF ₆ , HBF ₄ and HI _{5. A} method of forming a semiconductor fine particle layer, comprising forming an intermediate film comprising at least one compound selected from the group consisting of No. ₅ and forming the semiconductor fine particle layer on the intermediate film. In a laminated structure in which a semiconductor fine particle layer is formed on a metal oxide film,
On the metal oxide film,

With a polythiophene or a derivative thereof,

, RSO ₃ H (where R = alkyl, aryl), R′OSO ₃ H (where R ′ = H, alkyl, aryl), HCl, HClO ₄ , HPF ₆ , HBF ₄ and HI _5. A laminated structure comprising: forming an intermediate film made of at least one compound selected from the group consisting of No. 5; and forming the semiconductor fine particle layer on the intermediate film.

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