JP2004115761A - Light-emitting material for organic electroluminescent element and organic electroluminescent element by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent (EL) material having a highly luminous brightness and a long luminous life even having white luminous color, and an organic EL element by using the same. <P>SOLUTION: This luminous material for the organic EL element is expressed by formula [1] [wherein, A is expressed by formula [2] or formula [3] (wherein, R<SP>1</SP>, R<SP>4</SP>, R<SP>6</SP>and R<SP>7</SP>are each a monovalent phenyl which may have a substituent; and R<SP>2</SP>, R<SP>3</SP>, R<SP>5</SP>and R<SP>8</SP>are each a divalent phenyl which may have a substituent); B is a non-aromatic 2-20-membered ring which may contain O, S, Se or N; R<SP>a</SP>, R<SP>b</SP>are each H or an alkyl which may be substituted; and (n) is an integer of ≥1 and ≤5,000]. <P>COPYRIGHT: (C)2004,JPO

Description

［式中、Ａは下記一般式［２］もしくは一般式［３］を、
Ｂは、酸素原子、硫黄原子、セレン原子、もしくは窒素原子を含んでもよい非芳香族２〜２０員環を表し、
Ｒ^ａおよびＲ^ｂは水素原子もしくは置換されてもよいアルキル基を、
ｎは０以上５０００以下の整数をそれぞれ示す。］
一般式［２］
【化５】

［式中、Ｒ^１およびＲ^４は、１価のフェニル基であって、ハロゲン原子、置換もしくは未置換のアルキル基、置換もしくは未置換のアルコキシ基、置換もしくは未置換のチオアルコキシ基、シアノ基、アミノ基、モノもしくはジ置換アミノ基、水酸基、メルカルト基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアリールチオ基、置換もしくは未置換の芳香族環基、置換もしくは未置換の複素環基で置換されてもよい１価のフェニル基を表し、
Ｒ^２およびＲ^３は、２価のフェニル基（フェニレン基）であって、ハロゲン原子、置換もしくは未置換のアルキル基、置換もしくは未置換ののアルコキシ基、置換もしくは未置換のチオアルコキシ基、シアノ基、アミノ基、モノもしくはジ置換アミノ基、水酸基、メルカルト基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアリールチオ基、置換もしくは未置換の芳香族環基、置換もしくは未置換の複素環基で置換されてもよい２価のフェニル基を表し、
また、Ｒ^１〜Ｒ^４の置換基は、隣接した置換基同士で置換もしくは未置換の環を形成しても良い。Ｘは、２価の芳香族環残基、もしくは−Ａｒ−Ｚ−Ａｒ−
（Ａｒは炭素数６から２０の芳香族環残基であり、
Ｚは、直接結合するか、酸素原子、硫黄原子、セレン原子、またはこれらの原子を含んで良い２価の芳香族環残基、もしくは、これら原子を含んで良い２価の脂肪族残基を表す。）
を示す。］
一般式［３］
【化６】

［式中、Ｒ^６およびＲ^７は、ハロゲン原子、置換もしくは未置換のアルキル基、置換もしくは未置換のアルコキシ基、置換もしくは未置換のチオアルコキシ基、シアノ基、アミノ基、モノもしくはジ置換アミノ基、水酸基、メルカルト基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアリールチオ基、置換もしくは未置換の芳香族環基、置換もしくは未置換の複素環基で置換されてもよい１価のフェニル基を表し、
Ｒ^５およびＲ^８は、ハロゲン原子、置換もしくは未置換のアルキル基、置換もしくは未置換ののアルコキシ基、置換もしくは未置換のチオアルコキシ基、シアノ基、アミノ基、モノもしくはジ置換アミノ基、水酸基、メルカルト基、置換もしくは未置換のアリールオキシ基、置換もしくは未置換のアリールチオ基、置換もしくは未置換の芳香族環基、置換もしくは未置換の複素環基で置換されてもよい２価のフェニル基を表し、
また、Ｒ^５〜Ｒ^８の置換基は、隣接した置換基同士で置換もしくは未置換の環を形成しても良い。Ｘは、２価の芳香族環残基、もしくは−Ａｒ−Ｚ−Ａｒ−
（Ａｒは炭素数６から２０の芳香族環残基であり、
Ｚは、直接結合するか、酸素原子、硫黄原子、セレン原子、またはこれらの原子を含んで良い２価の芳香族環残基、もしくは、これら原子を含んで良い２価の脂肪族残基を表す。）
を示す。］
【００１１】
また、本発明は、さらに、共役系高分子を含む上記有機エレクトロルミネッセンス素子の発光材料に関する。
【００１２】
また、本発明は、発光が、白色である上記有機エレクトロルミネッセンス素子の発光材料に関する。
【００１３】
また、本発明は、一対の電極間に発光層または発光層を含む複数層の有機化合物薄膜を形成してなる有機エレクトロルミネッセンス素子において、発光層が上記発光材料を単独もしくは混合物として含有することを特徴とする有機エレクトロルミネッセンス素子に関する。
【００１４】
【発明の実施の形態】
本発明は、有機エレクトロルミネッセンス素子において、発光層に、一般式［１］で示されるアミン化合物が新規な有機発光材料として含まれることを特徴とする。
【００１５】
本発明における一般式［２］および一般式［３］で示される化合物のＲ^１〜Ｒ^８で示されるフェニル基に置換されてよいハロゲン原子としては弗素、塩素、臭素、ヨウ素がある。
置換もしくは未置換のアルキル基としては、メチル基、エチル基、プロピル基、ブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、ステアリル基、トリクロロメチル基、トリフロロメチル基、シクロプロピル基、シクロヘキシル基、１，３−シクロヘキサジエニル基、２−シクロペンテン−１−イル基、２，４−シクロペンタジエン−１−イリデニル基等がある。
【００１６】
置換もしくは未置換のアルコキシ基としては、メトキシ基、エトキシ基、プロポキシ基、ｎ−ブトキシ基、ｓｅｃ−ブトキシ基、ｔｅｒｔ−ブトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ステアリルオキシ基、トリフロロメトキシ基等がある。
【００１７】
置換もしくは未置換のチオアルコキシ基としては、メチルチオ基、エチルチオ基、プロピルチオ基、ブチルチオ基、ｓｅｃ−ブチルチオ基、ｔｅｒｔ−ブチルチオ基、ペンチルチオ基、ヘキシルチオ基、ヘプチルチオ基、オクチルチオ基等がある。
【００１８】
モノまたはジ置換アミノ基としては、メチルアミノ基、ジメチルアミノ基、エチルアミノ基、ジエチルアミノ基、ジプロピルアミノ基、ジブチルアミノ基、ジフェニルアミノ基、ビス（アセトオキシメチル）アミノ基、ビス（アセトオキシエチル）アミノ基、ビス（アセトオキシプロピル）アミノ基、ビス（アセトオキシブチル）アミノ基、ジベンジルアミノ基等がある。
置換もしくは未置換のアリールオキシ基としては、フェノキシ基、ｐ−ｔｅｒｔ−ブチルフェニキシ基、３−フルオロフェニキシ基等がある。
【００１９】
置換もしくは未置換のアリールチオ基としては、フェニルチオ基、３−フルオロフェニルチオ基等がある。
【００２０】
置換もしくは未置換の炭素環式芳香族環基としては、フェニル基、ビフェニレニル基、トリフェニレニル基、テトラフェニレニル基、３−ニトロフェニル基、４−メチルチオフェニル基、３，５−ジシアノフェニル基、ｏ−，ｍ−およびｐ−トリル基、キシリル基、ｏ−，ｍ−およびｐ−クメニル基、メシチル基、ペンタレニル基、インデニル基、ナフチル基、アズレニル基、ヘプタレニル基、アセナフチレニル基、フェナレニル基、フルオレニル基、アントリル基、アントラキノニル基、３−メチルアントリル基、フェナントリル基、トリフェニレニル基、ピレニル基、クリセニル基、２−エチル−１−クリセニル基、ピセニル基、ペリレニル基、６−クロロペリレニル基、ペンタフェニル基、ペンタセニル基、テトラフェニレニル基、ヘキサフェニル基、ヘキサセニル基、ルビセニル基、コロネニル基、トリナフチレニル基、ヘプタフェニル基、ヘプタセニル基、ピラントレニル基、オバレニル基等がある。
【００２１】
置換もしくは未置換の複素環式芳香族環基としては、チオニル基、フリル基、ピロリル基、イミダゾリル基、ピラゾリル基、ピリジル基、ピラジニル基、ピリミジニル基、ピリダジニル基、インドリル基、キノリル基、イソキノリル基、フタラジニル基、キノキサリニル基、キナゾリニル基、カルバゾリル基、アクリジニル基、フェナジニル基、フルフリル基、イソチアゾリル基、イソキサゾリル基、フラザニル基、フェノキサジニル基、ベンゾチアゾリル基、ベンゾオキサゾリル基、ベンズイミダゾリル基、２−メチルピリジル基、３−シアノピリジル基等があるが、上記置換基に具体的に限定されるものではない。
【００２２】
置換もしくは未置換の炭素環式芳香族環基としては、フェニル基、ビフェニレニル基、トリフェニレニル基、テトラフェニレニル基、３−ニトロフェニル基、４−メチルチオフェニル基、３，５−ジシアノフェニル基、ｏ−，ｍ−およびｐ−トリル基、キシリル基、ｏ−，ｍ−およびｐ−クメニル基、メシチル基、ペンタレニル基、インデニル基、ナフチル基、アズレニル基、ヘプタレニル基、アセナフチレニル基、フェナレニル基、フルオレニル基、アントリル基、アントラキノニル基、３−メチルアントリル基、フェナントリル基、トリフェニレニル基、ピレニル基、クリセニル基、２−エチル−１−クリセニル基、ピセニル基、ペリレニル基、６−クロロペリレニル基、ペンタフェニル基、ペンタセニル基、テトラフェニレニル基、ヘキサフェニル基、ヘキサセニル基、ルビセニル基、コロネニル基、トリナフチレニル基、ヘプタフェニル基、ヘプタセニル基、ピラントレニル基、オバレニル基等がある。
【００２３】
好ましいＲ^１〜Ｒ^８の置換基しては、水素原子（この場合は無置換体になる）炭素原子が１〜６個の低級アルキル基、もしくは低級アルコキシ基である。また、隣接した置換基同士で５ないし７員環の酸素原子、窒素原子、硫黄原子等が含まれてもよい脂肪族、炭素環式芳香族、複素環式芳香族、複素環を形成してもよく、これらの環の任意の位置にさらに置換基を有してもよい。
【００２４】
本発明のＸ、Ｚ、Ａｒの２価の芳香族環残基としては、炭素原子が１〜６個の低級アルキル基、もしくは低級アルコキシ基を置換基として有してもよいフェニル基、ビフェニル基、３，３’−ジメチルビフェニル基、ターフェニル基、ナフチル基、アントラニル基、フェナントレニル基、フルオレニル基、９，９’−ビフェニル−フルオレニル基、スチルベン基、ピレニル基等がある。また、２価の芳香族環基中の２個以上の芳香族環があるときは、さらに、低級アルキル基、酸素、硫黄等で結合しても良い。
【００２５】
本発明のＺの２価の脂肪族残基としては、前記置換もしくは未置換のアルキル基で例示したものの２価の残基などが挙げられる。
【００２６】
一般式［１］のＡで示される置換もしくは未置換のジアミン誘導体の代表例を具体的に表１に例示するが、これらに限定されるものではない。
表１
【００２７】
【表１】

【００２８】

【００２９】

【００３０】

【００３１】

【００３２】

【００３３】

【００３４】

【００３５】
一般式［１］のＢで示される酸素原子、硫黄原子、セレン原子、もしくは窒素原子を含んでもよい非芳香族２〜２０員環としては、置換基を有してよいシクロプロピル基、シクロブチル基、シクロペンチル基、シクロヘキシル基、４−メチルシクロヘキシル基、３−メチルシクロヘキシル基、２−メチルシクロヘキシル基、２，４−ジケチルシクロヘキシル基、シクロヘプチル基、シクロオクチル基等がある。この代表例を具体的に表２に例示するが、これらに限定されるものではない。
表２
【００３６】
【表２】

【００３７】

【００３８】

【００３９】

【００４０】
一般式［１］のＲ^ａおよびＲ^ｂで示されるアルキル基は、一般式［２］および一般式［３］の説明で例示した置換基で置換されていてもよい。
【００４１】
一般式［１］で示されるジフェニルアミン重合体は、例えば、酢酸溶媒中、置換もしくは未置換の脂環式カルボニル化合物に、０．５〜４倍モルの置換もしくは未置換のジフェニルアミン化合物を、メタンスルホン酸等の酸触媒と共に１００℃にて３０時間脱水反応させることにより、合成することができる。
【００４２】
また、本発明で用いられる酸触媒としては、メタンスルホン酸の代わりに、トリフルオロ酢酸、ｐ−トルエンスルホン酸の様な有機酸、または、硫酸、塩酸、ルイス酸等も可能である。また、有機溶剤としては、酢酸の他に、１，４−ジオキサン、エーテル、石油エーテル等も可能である。ここで、反応時間を５０時間以上にすることにより、分子量１万以上の化合物が多く合成され、逆に２時間以下であると、分子量２０００以下となる。
【００４３】
本発明の一般式［１］の代表例を表３に具体的に示すが、一般式［１］の化合物は以下の代表例に限定されるものではない。
表３
【００４４】
【表３】

【００４５】
本発明の発光材料は、同一層中で他の発光材料、正孔もしくは電子輸送性化合物と混合して使用してもさしつかえない。本発明の発光材料は発光性、正孔輸送性に優れているので、正孔輸送性発光材料として極めて有効に使用することができる。
本発明の発光材料は、共役系高分子、ポリビニルカルバゾール、ポリシラン、非共役系の高分子材料等と併用できる。
白色発光をさせるなどの場合には、共役系高分子と混合することも可能である。なお、このときの発光は、エキサイプレックス発光と、一般式［１］の化合物自体の発光とが同時に発光し、白色となっている場合があることが推測される。
【００４６】
本発明でいう共役系高分子とは、炭素−炭素またはヘテロ原子を含む二重結合（または、三重結合）が単結合と交互に長く連なった共役系を分子骨格とした共役系高分子である。さらに詳しくは、炭素−炭素の単結合と二重結合が交互に長く連なった脂肪族共役系であるポリアセチレン、芳香族炭化水素が長く結合する事により共役が発達した芳香族共役系であるポリ（パラフェニレン）、ポリ（アルキルフルオレン）誘導体、複素環化合物が結合して共役系が発達した複素環式共役系であるポリピロール、ポリチオフェン、脂肪族または芳香族の共役系をヘテロ原子で結合した含ヘテロ原子共役系であるポリアニリン、上記各種共役系の構成単位が交互に結合した混合型共役系であるポリ（フェニレンビニレン）等が上げられる。
代表例を表４に具体的に示すが、本発明は以下の代表例に限定されるものではない。
表４
【００４７】
【表４】

【００４８】

【００４９】
また、この他に、アントラセン、ナフタレン、フェナントレン、ピレン、テトラセン、コロネン、クリセン、フルオレセイン、ペリレン、フタロペリレン、ナフタロペリレン、ペリノン、フタロペリノン、ナフタロペリノン、ジフェニルブタジエン、テトラフェニルブタジエン、クマリン、オキサジアゾール、アルダジン、ビスベンゾキサゾリン、ビススチリル、ピラジン、シクロペンタジエン、キノリン金属錯体、アミノキノリン金属錯体、ベンゾキノリン金属錯体、イミン、ジフェニルエチレン、ビニルアントラセン、ジアミノカルバゾール、ピラン、チオピラン、ポリメチン、メロシアニン、イミダゾールキレート化オキシノイド化合物、キナクリドン、ルブレンおよび色素レーザー用や増白用の蛍光色素等があるが、これらに限定されるものではない。
【００５０】
本発明の発光材料および共に発光層に使用できる上記の化合物の発光層中での存在比率はどれが主成分であってもよい。つまり、上記の化合物および本発明における化合物のそれぞれの組み合わせにより、本発明における化合物は発光層を形成する主材料にも他の主材料中へのドーピンク材料にも成り得る。
【００５１】
発光層には、必要があれば、本発明の発光材料に加えて、さらなる公知の発光材料、ドーピング材料、正孔注入材料や電子注入材料を使用することもできる。有機ＥＬ素子は、多層構造にすることにより、クエンチングによる輝度や寿命の低下を防ぐことができる。必要があれば、発光材料、ドーピング材料、正孔注入材料や電子注入材料を組み合わせて使用することが出来る。また、ドーピング材料により、発光輝度や発光効率の向上、赤色や青色の発光を得ることもできる。また、正孔注入帯域、発光層、電子注入帯域は、それぞれ二層以上の層構成により形成されても良い。その際には、正孔注入帯域の場合、電極から正孔を注入する層を正孔注入層、正孔注入層から正孔を受け取り発光層まで正孔を輸送する層を正孔輸送層と呼ぶ。同様に、電子注入帯域の場合、電極から電子を注入する層を電子注入層、電子注入層から電子を受け取り発光層まで電子を輸送する層を電子輸送層と呼ぶ。これらの各層は、材料のエネルギー準位、耐熱性、有機層もしくは金属電極との密着性等の各要因により選択されて使用される。
【００５２】
正孔注入材料としては、正孔を輸送する能力を持ち、陽極からの正孔注入効果、発光層または発光材料に対して優れた正孔注入効果を有し、発光層で生成した励起子の電子注入帯域または電子注入材料への移動を防止し、かつ薄膜形成能力の優れた化合物が挙げられる。具体的には、フタロシアニン誘導体、ナフタロシアニン誘導体、ポルフィリン誘導体、オキサゾール、オキサジアゾール、トリアゾール、イミダゾール、イミダゾロン、イミダゾールチオン、ピラゾリン、ピラゾロン、テトラヒドロイミダゾール、オキサゾール、オキサジアゾール、ヒドラゾン、アシルヒドラゾン、ポリアリールアルカン、スチルベン、ブタジエン、ベンジジン型トリフェニルアミン、スチリルアミン型トリフェニルアミン、ジアミン型トリフェニルアミン等と、それらの誘導体、およびポリビニルカルバゾール、ポリシラン、導電性高分子等の高分子材料等があるが、これらに限定されるものではない。
【００５３】
本発明の有機ＥＬ素子において使用できる正孔注入材料の中で、さらに効果的な正孔注入材料は、アリールアミン誘導体、フタロシアニン化合物ないしはトリフェニレン誘導体である。アリールアミン誘導体の具体例としては、トリフェニルアミン、トリトリルアミン、トリルジフェニルアミン、Ｎ，Ｎ’−ジフェニル−Ｎ，Ｎ’−ジ−ｍ−トリル−４，４’−ビフェニルジアミン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラ（ｐ−トリル）−ｐ−フェニレンジアミン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラ−ｐ−トリル−４，４’−ビフェニルジアミン、Ｎ，Ｎ’−ジフェニル−Ｎ，Ｎ’−ジ（１−ナフチル）−４，４’−ビフェニルジアミン、Ｎ，Ｎ’−ジ（４−ｎ−ブチルフェニル）−Ｎ，Ｎ’−ジ−ｐ−トリル−９，１０−フェナントレンジアミン、４，４’，４”−トリス（Ｎ−フェニル−Ｎ−ｍ−トリルアミノ）トリフェニルアミン、１，１−ビス［４−（ジ−ｐ−トリルアミノ）フェニル］シクロヘキサン等、もしくはこれらの芳香族三級アミン骨格を有したオリゴマーもしくはポリマー等があるが、これらに限定されるものではない。
【００５４】
電子注入材料としては、電子を輸送する能力を持ち、陰極からの正孔注入効果、発光層または発光材料に対して優れた電子注入効果を有し、発光層で生成した励起子の正孔注入帯域への移動を防止し、かつ薄膜形成能力の優れた化合物が挙げられる。例えば、フルオレノン、アントラキノジメタン、ジフェノキノン、チオピランジオキシド、オキサゾール、オキサジアゾール、トリアゾール、イミダゾール、ペリレンテトラカルボン酸、フレオレニリデンメタン、アントラキノジメタン、アントロン等とそれらの誘導体があるが、これらに限定されるものではない。また、正孔注入材料に電子受容物質を、電子注入材料に電子供与性物質を添加することにより増感させることもできる。
【００５５】
本発明の有機ＥＬ素子において、さらに効果的な電子注入材料は、金属錯体化合物もしくは含窒素五員環誘導体である。具体的には、金属錯体化合物としては、８−ヒドロキシキノリナートリチウム、ビス（８−ヒドロキシキノリナート）亜鉛、ビス（８−ヒドロキシキノリナート）銅、ビス（８−ヒドロキシキノリナート）マンガン、トリス（８−ヒドロキシキノリナート）アルミニウム、トリス（２−メチル−８−ヒドロキシキノリナート）アルミニウム、トリス（８−ヒドロキシキノリナート）ガリウム、ビス（１０−ヒドロキシベンゾ［ｈ］キノリナート）ベリリウム、ビス（１０−ヒドロキシベンゾ［ｈ］キノリナート）亜鉛、ビス（２−メチル−８−ヒドロキシキノリナート）クロロガリウム、ビス（２−メチル−８−ヒドロキシキノリナート）（ｏ−クレゾラート）ガリウム、ビス（２−メチル−８−ヒドロキシキノリナート）（１−ナフトラート）アルミニウム、ビス（２−メチル−８−ヒドロキシキノリナート）（２−ナフトラート）ガリウム、ビス（２−メチル−８−ヒドロキシキノリナート）フェノラートガリウム、ビス（ｏ−（２−ベンゾオキサゾリル）フェノラート）亜鉛、ビス（ｏ−（２−ベンゾチアゾリル）フェノラート）亜鉛、ビス（ｏ−（２−ベンゾトリアゾリル）フェノラート）亜鉛等があるが、これらに限定されるものではない。
【００５６】
本発明の発光材料は、ガラス転移点や融点が高い為、電界発光時における有機層中、有機層間もしくは、有機層と金属電極間で発生するジュール熱に対する耐性（耐熱性）が向上するので、有機ＥＬ素子材料として使用した場合、高い発光輝度を示し、長時間発光させる際にも有利である。
【００５７】
本発明の高分子の成膜方法としては、特に限定はなく、例えば粉末状態からの真空蒸着法、溶媒に溶解した後、塗布する方法（例えばスピンコーテング法、キャスチング法、デッピング法、バーコート法、ロールコート法など）などを用いることが出来るが、素子製造工程の簡略化、加工性、大面積化の観点から塗布方式が好ましい。塗布方式で成膜する場合に用いる溶媒としては、ジクロロエタン、ジクロロメタン、クロロホルム、などの有機ハロゲン系溶媒、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、トルエン、キシレンなどの芳香族炭化水素系溶媒、ジメチルホルムアミド、ジメチルアセトアミドなどのアミド系溶媒、酢酸エチル、参観ブチルなどのエステル系溶媒、またはこれらの混合溶媒であっても良い。高分子の構造、分子量によっても異なるが、通常溶媒の０．０１から１０重量％、好ましくは０．１から５重量％溶解した溶液を用いて成膜する。
【００５８】
有機ＥＬ素子は、陽極と陰極間に一層もしくは多層の有機薄膜を形成した素子である。一層型の場合、陽極と陰極との間に発光層を設けている。発光層は、発光材料を含有し、それに加えて陽極から注入した正孔、もしくは陰極から注入した電子を発光材料まで輸送させるために、正孔注入材料もしくは電子注入材料を含有しても良い。しかしながら、本発明の発光材料は、高い正孔輸送能力を併せ持ち、均一な薄膜を形成することができるので、本発明の発光材料のみで発光層を形成することも可能である。多層型は、（陽極／正孔注入帯域／発光層／陰極）、（陽極／発光層／電子注入帯域／陰極）、（陽極／正孔注入帯域／発光層／電子注入帯域／陰極）の多層構成で積層した有機ＥＬ素子がある。
【００５９】
有機ＥＬ素子の陽極に使用される導電性物質としては、４ｅＶより大きな仕事関数を持つものが好適であり、炭素、アルミニウム、バナジウム、鉄、コバルト、ニッケル、タングステン、銀、金、白金、パラジウム等およびそれらの合金、ＩＴＯ基板、ＮＥＳＡ基板と称される酸化スズ、酸化インジウム等の酸化金属、さらにはポリチオフェンやポリピロール等の有機導電性樹脂が用いられる。
陰極に使用される導電性物質としては、４ｅＶより小さな仕事関数を持つものが好適であり、マグネシウム、カルシウム、錫、鉛、チタニウム、イットリウム、リチウム、ルテニウム、マンガン等およびそれらの合金が用いられるが、これらに限定されるものではない。陽極および陰極は、必要があれば二層以上の層構成により形成されていても良い。
【００６０】
本発明の有機ＥＬ素子は、壁掛けテレビ等のフラットパネルディスプレイや、平面発光体として、複写機やプリンター等の光源、液晶ディスプレイや計器類等の光源、表示板、標識灯等へ応用が考えられ、その工業的価値は非常に大きい。
【００６１】
【実施例】
以下、本発明を実施例に基づきさらに詳細に説明する。説明中、部は重量部、％は重量％を表す。
化合物（１）の合成方法
酢酸１５部中に、シクロヘキサノン１５部、４，４−ビス（２，４−ジメチルフェニルフェニルアミノ）ビフェニル２４部、およびメタンスルホン酸０．５部を入れ、１００℃にて２０時間加熱撹拌した。その後、５００部の水で希釈し、希水酸化ナトリウム水溶液で中和した。この後、酢酸エチルで抽出を行い、濃縮し、シリカゲルを用いたカラムクロマトグラフィーにより精製を行ない白色の蛍光を有する粉末１８部を得た。スチレン換算によるＧＰＣ分析により、分子量分析を行った結果、化合物（１）であることを確認した。
この化合物の赤外吸収スペクトル（ＫＢｒ錠剤法）を図１に示す。
【００６２】
化合物（４）の合成方法
酢酸２１部中に、４−メチルシクロヘキサノン１８部、９，１０−ビス（４−ｎ−ブチルフェニルフェニルアミノ）フェナントレン２０部、およびメタンスルホン酸０．５部を入れ、１００℃にて２５時間加熱撹拌した。その後、４００部の水で希釈し、希水酸化ナトリウム水溶液で中和した。この後、酢酸エチルで抽出を行い、濃縮し、シリカゲルを用いたカラムクロマトグラフィーにより精製を行ない白色の蛍光を有する粉末１５部を得た。スチレン換算によるＧＰＣ分析により分子量分析を行った結果、化合物（４）であることを確認した。
【００６３】
化合物（１０）の合成方法
酢酸３０部中に、４−メチルシクロヘキサノン１５部、１，５−ビス（３，４−ジメチルフェニルフェニルアミノ）ナフタレン１８部、およびメタンスルホン酸０．５部を入れ、１００℃にて８０時間加熱撹拌した。その後、５００部の水で希釈し、希水酸化ナトリウム水溶液で中和した。この後、酢酸エチルで抽出を行い、濃縮し、シリカゲルを用いたカラムクロマトグラフィーにより精製を行ない白色の蛍光を有する粉末７部を得た。スチレン換算によるＧＰＣ分析により分子量分析を行った結果、化合物（１０）であることを確認した。
【００６４】
以下に本発明の発光材料を用いた実施例を示す。本例では、電極面積２ｍｍ×２ｍｍの有機ＥＬ素子の特性を測定した。
実施例１
洗浄したＩＴＯ電極付きガラス板上に、化合物（１）を２％の濃度でトルエンに溶解分散させ、スピンコーティング法により１００ｎｍの膜厚の発光層を得た。その上に、Ｃａを４０ｎｍ、Ａｌを８０ｎｍの膜厚の電極を形成して、有機ＥＬ素子を得た。この素子は、直流電圧８Ｖで、発光輝度２０ｃｄ／ｍ^２、発光効率０．０５ｌｍ／Ｗが得られた。
【００６５】
実施例２
洗浄したＩＴＯ電極付きガラス板上に、ＰＥＤＯＴをスピンコート法で５０ｎｍの膜厚に製膜し、次に、化合物（１）を２％の濃度でトルエンに溶解させ、スピンコーティング法により１００ｎｍの膜厚の発光層を得た。その上に、Ｃａを４０ｎｍ、Ａｌを８０ｎｍの膜厚の電極を形成して、有機ＥＬ素子を得た。この素子は、直流電圧６Ｖで、発光輝度７０ｃｄ／ｍ^２、発光効率０．１ｌｍ／Ｗが得られた。この素子の発光スペクトルを図２にしめす。
【００６６】
実施例３
洗浄したＩＴＯ電極付きガラス板上に、ＰＥＤＯＴをスピンコート法で５０ｎｍの膜厚に製膜し、次に、化合物（１）に化合物（Ｐ−２）で示されるポリアルキルフルオレン誘導体を４：６の割合で混合した２％の濃度でトルエンに溶解させ、スピンコーティング法により１００ｎｍの膜厚の発光層を得た。その上に、Ｃａを４０ｎｍ、Ａｌを８０ｎｍの膜厚の電極を形成して、有機ＥＬ素子を得た。この素子は、直流電圧６Ｖで、発光輝度１５００ｃｄ／ｍ^２、発光効率０．５１ｍ／Ｗが得られた。この素子の発光スペクトルを図３にしめす。
【００６７】
実施例４−８
洗浄したＩＴＯ電極付きガラス板上に、ＰＥＤＯＴをスピンコート法で５０ｎｍの膜厚に製膜し、次に、表３に示した化合物に化合物（Ｐ−２）を４：６の割合で混合した２％の濃度でトルエンに溶解させ、スピンコーティング法により１００ｎｍの膜厚の発光層を得た。その上に、Ｃａを４０ｎｍ、Ａｌを８０ｎｍの膜厚の電極を形成して、有機ＥＬ素子を得た。この素子は、直流電圧６Ｖで、表５に示した発光輝度を得た。
【００６８】
表５
【表５】

【００６９】
比較例１
発光層に化合物（Ｐ−２）のみを使用した実施例２の有機ＥＬ素子を作成した。この素子は、直流電圧８Ｖで発光輝度約３０ｃｄ／ｍ^２発光効率０．０３ｌｍ／Ｗが得られた。
この素子の発光スペクトルを図４に示す。
【００７０】
本実施例で示された全ての有機ＥＬ素子について、連続発光させたところ、１０００時間以上初期輝度の５０％以上の輝度を観測出来たが、比較例１の素子を同様の条件で連続発光させたところ、１０時間で初期感度の５０％以下の輝度になり、ダークスポットの数も極めて多くなった。本発明の正孔輸送材料は高分子量化されているので、有機ＥＬ素子としての耐熱性が極めて向上している。本発明の全ての化合物のガラス転移温度は、それぞれ１４０℃以上であり、本発明の発光材料が大きく改良されていることがわかる。
本発明の有機ＥＬ素子は発光効率、発光輝度の向上と長寿命化を達成するものであり、併せて使用される発光物質、発光補助材料、正孔輸送材料、電子輸送材料、増感剤、樹脂、電極材料等および素子作製方法を限定するものではない。
【００７１】
【発明の効果】
本発明により、従来に比べて高発光効率、高輝度であり、長寿命の白色有機ＥＬ素子を得ることができた。
【図面の簡単な説明】
【図１】化合物（１）の赤外線吸収スペクトル図
【図２】実施例２の素子の、発光スペクトル図
【図３】実施例３の素子に、発光スペクトル図
【図４】比較例１の素子の、発光スペクトル図[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting material for an organic electroluminescence (EL) element used for a flat light source and a display, and a high-luminance light emitting element.
[0002]
[Prior art]
2. Description of the Related Art An EL element using an organic substance is expected to be used as a solid-state light-emitting inexpensive large-area full-color display element, and many developments have been made. In general, an EL element includes a light emitting layer and a pair of opposed electrodes sandwiching the light emitting layer. In light emission, when an electric field is applied between both electrodes, electrons are injected from the cathode side, holes are injected from the anode side, the electrons recombine with holes in the light emitting layer, and the energy level is changed from the conduction band. This is a phenomenon in which energy is emitted as light when returning to the valence band.
[0003]
The conventional organic EL element has a higher driving voltage and lower light emission luminance and light emission efficiency than the inorganic EL element. In addition, the characteristics deteriorated remarkably, and practical use has not been achieved.
In recent years, an organic EL element in which a thin film containing an organic compound having high fluorescence quantum efficiency that emits light at a low voltage of 10 V or less has been reported, and has attracted attention (see Non-Patent Document 1). This method uses a metal chelate complex for a light emitting layer and an amine compound for a hole injection layer to obtain high-luminance green light emission. The luminance reaches several thousand cd / m ² at a DC voltage of 6 to 7 V. ing. However, the production of an EL device involving the operation of vapor-depositing an organic compound has a problem in productivity, and from the viewpoint of simplifying the production process and increasing the area, it is desirable to produce the device by a coating method.
[0004]
A polyphenylenevinylene-based polymer is known as a light-emitting material of an EL element used for producing a coating-type EL element which is advantageous in productivity (see Non-Patent Document 2), but has a light-emitting portion in a polymer main chain. Therefore, there are problems such as difficulty in controlling the concentration of the luminescent material, and difficulty in finely controlling the color tone and the luminous intensity. Similarly, as an EL element using a coating method, for example, there is an element that disperses a low molecular weight dye in polyvinyl carbazole (see Patent Document 1). Adjustment of color tone and emission intensity is relatively easy because the dye type and dye concentration can be changed arbitrarily.However, in these devices, low molecular compounds are dispersed in the polymer, which causes dye aggregation and phase separation. There are problems such as being likely to occur, uniform light emission not being obtained, and poor light emission characteristics.
[0005]
A white light emitting element has a wider application range than a blue or green single color light emitting element. For example, in monochrome display, white color is preferred, it can be used for backlight of liquid crystal display, and it can be applied to full color display by combining with color filter. In particular, full-color display requires fine arrangement of blue, red, and green light-emitting elements.However, if a color filter is used to separate white light into three primary colors of RGB, cost can be reduced. Furthermore, application to various light sources, electric equipment, indoor lighting, and the like are also possible.
[0006]
As a light emitting material for an organic EL element for obtaining white light emission (see Non-Patent Document 3), it is difficult to obtain perfect white light, and no material that emits white light using only a single material has been found. As a polymer-based white device, it is possible to emit white by mixing a plurality of dyes by doping a polymer into a light-emitting layer with a dye (see Non-Patent Document 4). At present, it is not satisfactory as a display material, and it is desired to realize a white light emitting device having higher luminance and better color purity.
[0007]
[Patent Document 1]
JP-A-4-212286 [Non-Patent Document 1]
Applied Physics Letters, 51, 913 pages, 1987 [Non-Patent Document 2]
Advanced Materials, Volume 2, page 4 1992 Advanced Materials, Volume 9, page 551 1997 [Non-Patent Document 3]
Japan Journal Applied Physics, 35, L, pp. 1339, 1996 [Non-Patent Document 4]
Applied Physics Letters, 64, 815 pages, 1994
[Problems to be solved by the invention]
[0009]
An object of the present invention is to provide a light emitting material for an organic EL device having a high light emission luminance and a long light emitting life while having a white light emitting color, and an organic EL device using the same. As a result of intensive studies made by the present inventors, the use of an amine compound having a specific chemical structure represented by the general formula [1] as a light emitting material allows an organic EL device to emit white light, and to have a low luminance and a high luminous efficiency. It was found to be high and the luminescence life was excellent.
[0010]
[Means for Solving the Problems]
The present invention relates to a light-emitting material for an organic electroluminescence device represented by the following general formula [1].
General formula [1]
Embedded image

[Wherein A represents the following general formula [2] or general formula [3]:
B represents a non-aromatic 2 to 20 membered ring which may contain an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom;
R ^a and R ^b represent a hydrogen atom or an alkyl group which may be substituted,
n shows the integer of 0 or more and 5000 or less, respectively. ]
General formula [2]
Embedded image

[Wherein R ¹ and R ⁴ are monovalent phenyl groups, and are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group , Amino group, mono- or di-substituted amino group, hydroxyl group, Mercart group, substituted or unsubstituted aryloxy group, substituted or unsubstituted arylthio group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted heterocyclic ring Represents a monovalent phenyl group which may be substituted with a group,
R ² and R ³ are a divalent phenyl group (phenylene group), and are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group, Group, amino group, mono- or di-substituted amino group, hydroxyl group, mercart group, substituted or unsubstituted aryloxy group, substituted or unsubstituted arylthio group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted heterocyclic group Represents a divalent phenyl group which may be substituted with a ring group,
In addition, the substituents of R ^{1 to} R ⁴ may form a substituted or unsubstituted ring with adjacent substituents. X is a divalent aromatic ring residue or -Ar-Z-Ar-
(Ar is an aromatic ring residue having 6 to 20 carbon atoms,
Z represents a direct bond, an oxygen atom, a sulfur atom, a selenium atom, a divalent aromatic ring residue which may contain these atoms, or a divalent aliphatic residue which may contain these atoms. Represent. )
Is shown. ]
General formula [3]
Embedded image

[Wherein R ⁶ and R ⁷ are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group, an amino group, a mono- or di-substituted amino group; A monovalent group which may be substituted with a group, a hydroxyl group, a Mercart group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted aromatic ring group, or a substituted or unsubstituted heterocyclic group Represents a phenyl group,
R ⁵ and R ⁸ are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group, an amino group, a mono- or di-substituted amino group, a hydroxyl group A mervalent group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted aromatic ring group, a divalent phenyl group which may be substituted with a substituted or unsubstituted heterocyclic group Represents
Further, the substituents of R ^{5 to} R ⁸ may form a substituted or unsubstituted ring with adjacent substituents. X is a divalent aromatic ring residue or -Ar-Z-Ar-
(Ar is an aromatic ring residue having 6 to 20 carbon atoms,
Z represents a direct bond, an oxygen atom, a sulfur atom, a selenium atom, a divalent aromatic ring residue which may contain these atoms, or a divalent aliphatic residue which may contain these atoms. Represent. )
Is shown. ]
[0011]
In addition, the present invention further relates to a light emitting material of the organic electroluminescence device containing the conjugated polymer.
[0012]
Further, the present invention relates to a light-emitting material of the organic electroluminescence device, which emits white light.
[0013]
In addition, the present invention provides an organic electroluminescence device in which a light emitting layer or a plurality of organic compound thin films including a light emitting layer is formed between a pair of electrodes, wherein the light emitting layer contains the light emitting material alone or as a mixture. The present invention relates to a characteristic organic electroluminescence element.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is characterized in that, in the organic electroluminescence element, the light emitting layer contains the amine compound represented by the general formula [1] as a novel organic light emitting material.
[0015]
The halogen atom which may be substituted by the phenyl group represented by R ^{1 to} R ⁸ in the compounds represented by the general formulas [2] and [3] in the present invention includes fluorine, chlorine, bromine and iodine.
Examples of the substituted or unsubstituted alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a stearyl group, and a trichloromethyl group. Trifluoromethyl group, cyclopropyl group, cyclohexyl group, 1,3-cyclohexadienyl group, 2-cyclopenten-1-yl group, 2,4-cyclopentadiene-1-yridenyl group and the like.
[0016]
Examples of the substituted or unsubstituted alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, a stearyloxy group, and a trifluoromethoxy group. Etc.
[0017]
Examples of the substituted or unsubstituted thioalkoxy groups include methylthio, ethylthio, propylthio, butylthio, sec-butylthio, tert-butylthio, pentylthio, hexylthio, heptylthio, octylthio, and the like.
[0018]
Mono- or di-substituted amino groups include methylamino, dimethylamino, ethylamino, diethylamino, dipropylamino, dibutylamino, diphenylamino, bis (acetooxymethyl) amino, bis (acetooxy) Examples include an ethyl) amino group, a bis (acetooxypropyl) amino group, a bis (acetooxybutyl) amino group, and a dibenzylamino group.
Examples of the substituted or unsubstituted aryloxy group include a phenoxy group, a p-tert-butylphenoxy group, and a 3-fluorophenoxy group.
[0019]
Examples of the substituted or unsubstituted arylthio group include a phenylthio group and a 3-fluorophenylthio group.
[0020]
Examples of the substituted or unsubstituted carbocyclic aromatic ring group include a phenyl group, a biphenylenyl group, a triphenylenyl group, a tetraphenylenyl group, a 3-nitrophenyl group, a 4-methylthiophenyl group, a 3,5-dicyanophenyl group, o-, m- and p-tolyl group, xylyl group, o-, m- and p-cumenyl group, mesityl group, pentalenyl group, indenyl group, naphthyl group, azulenyl group, heptalenyl group, acenaphthylenyl group, phenalenyl group, fluorenyl Group, anthryl group, anthraquinonyl group, 3-methylanthryl group, phenanthryl group, triphenylenyl group, pyrenyl group, chrysenyl group, 2-ethyl-1-chrysenyl group, picenyl group, perylenyl group, 6-chloroperylenyl group, pentaphenyl group , Pentacenyl group, tetraphenylenyl group, f Safeniru group, hexacenyl group, rubicenyl group, coronenyl groups, trinaphthylenyl groups, heptacenyl groups, pyranthrenyl groups, and the like ovalenyl group.
[0021]
Examples of the substituted or unsubstituted heterocyclic aromatic ring group include a thionyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an indolyl group, a quinolyl group, and an isoquinolyl group , Phthalazinyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenazinyl, furfuryl, isothiazolyl, isoxazolyl, furazanyl, phenoxazinyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, 2-methyl There are a pyridyl group, a 3-cyanopyridyl group and the like, but it is not specifically limited to the above substituents.
[0022]
Examples of the substituted or unsubstituted carbocyclic aromatic ring group include a phenyl group, a biphenylenyl group, a triphenylenyl group, a tetraphenylenyl group, a 3-nitrophenyl group, a 4-methylthiophenyl group, a 3,5-dicyanophenyl group, o-, m- and p-tolyl group, xylyl group, o-, m- and p-cumenyl group, mesityl group, pentalenyl group, indenyl group, naphthyl group, azulenyl group, heptalenyl group, acenaphthylenyl group, phenalenyl group, fluorenyl Group, anthryl group, anthraquinonyl group, 3-methylanthryl group, phenanthryl group, triphenylenyl group, pyrenyl group, chrysenyl group, 2-ethyl-1-chrysenyl group, picenyl group, perylenyl group, 6-chloroperylenyl group, pentaphenyl group , Pentacenyl group, tetraphenylenyl group, f Safeniru group, hexacenyl group, rubicenyl group, coronenyl groups, trinaphthylenyl groups, heptacenyl groups, pyranthrenyl groups, and the like ovalenyl group.
[0023]
Preferred substituents for R ^{1 to} R ⁸ are a lower alkyl group having 1 to 6 hydrogen atoms (in this case, unsubstituted), or a lower alkoxy group. Adjacent substituents may form an aliphatic, carbocyclic aromatic, heteroaromatic, or heterocyclic ring which may contain a 5- to 7-membered oxygen atom, nitrogen atom, sulfur atom, etc. And may further have a substituent at any position of these rings.
[0024]
As the divalent aromatic ring residue of X, Z and Ar of the present invention, a phenyl group or a biphenyl group which may have a lower alkyl group having 1 to 6 carbon atoms or a lower alkoxy group as a substituent. , 3,3'-dimethylbiphenyl group, terphenyl group, naphthyl group, anthranyl group, phenanthrenyl group, fluorenyl group, 9,9'-biphenyl-fluorenyl group, stilbene group, pyrenyl group and the like. When there are two or more aromatic rings in the divalent aromatic ring group, they may be further bonded by a lower alkyl group, oxygen, sulfur or the like.
[0025]
Examples of the divalent aliphatic residue of Z in the present invention include the divalent residues exemplified for the aforementioned substituted or unsubstituted alkyl groups.
[0026]
Representative examples of the substituted or unsubstituted diamine derivative represented by A in the general formula [1] are specifically shown in Table 1, but are not limited thereto.
Table 1
[0027]
[Table 1]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]
Examples of the non-aromatic 2 to 20-membered ring which may contain an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom represented by B in the general formula [1] include a cyclopropyl group and a cyclobutyl group which may have a substituent. , Cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 3-methylcyclohexyl, 2-methylcyclohexyl, 2,4-diketylcyclohexyl, cycloheptyl, cyclooctyl and the like. This representative example is specifically illustrated in Table 2, but is not limited thereto.
Table 2
[0036]
[Table 2]

[0037]

[0038]

[0039]

[0040]
The alkyl groups represented by R ^a and R ^b in the general formula [1] may be substituted with the substituents exemplified in the description of the general formulas [2] and [3].
[0041]
The diphenylamine polymer represented by the general formula [1] is obtained, for example, by adding a substituted or unsubstituted alicyclic carbonyl compound to a substituted or unsubstituted alicyclic carbonyl compound in a acetic acid solvent by 0.5 to 4 times the molar amount of a substituted or unsubstituted diphenylamine compound. It can be synthesized by performing a dehydration reaction at 100 ° C. for 30 hours together with an acid catalyst such as an acid.
[0042]
Further, as the acid catalyst used in the present invention, organic acids such as trifluoroacetic acid and p-toluenesulfonic acid, or sulfuric acid, hydrochloric acid, Lewis acid and the like can be used instead of methanesulfonic acid. Further, as the organic solvent, in addition to acetic acid, 1,4-dioxane, ether, petroleum ether and the like are also possible. Here, by setting the reaction time to 50 hours or more, many compounds having a molecular weight of 10,000 or more are synthesized. Conversely, if the reaction time is 2 hours or less, the molecular weight becomes 2000 or less.
[0043]
Representative examples of the general formula [1] of the present invention are specifically shown in Table 3, but the compounds of the general formula [1] are not limited to the following typical examples.
Table 3
[0044]
[Table 3]

[0045]
The luminescent material of the present invention may be used in a mixture with another luminescent material, a hole or electron transporting compound in the same layer. Since the luminescent material of the present invention is excellent in luminescent property and hole transport property, it can be used very effectively as a hole transporting luminescent material.
The light emitting material of the present invention can be used in combination with a conjugated polymer, polyvinyl carbazole, polysilane, a non-conjugated polymer material, or the like.
In the case of emitting white light, for example, it is possible to mix with a conjugated polymer. In this case, it is presumed that the exciplex emission and the emission of the compound of the general formula [1] themselves are emitted at the same time, and the emission is white in some cases.
[0046]
The conjugated polymer referred to in the present invention is a conjugated polymer having a molecular skeleton of a conjugated system in which double bonds (or triple bonds) containing carbon-carbon or heteroatoms are alternately and long connected to single bonds. . More specifically, polyacetylene, which is an aliphatic conjugated system in which carbon-carbon single bonds and double bonds are alternately and continuously long, and poly (a), which is an aromatic conjugated system in which conjugation has developed due to long bonding of aromatic hydrocarbons Hetero-containing heteroatom in which polypyrrole, polythiophene, aliphatic or aromatic conjugated system, which is a heterocyclic conjugated system in which a conjugated system is developed by bonding a polyphenylene), poly (alkylfluorene) derivative, or heterocyclic compound, with a heteroatom Examples include polyaniline, which is an atom conjugated system, and poly (phenylenevinylene), which is a mixed conjugated system in which constituent units of the various conjugated systems are alternately bonded.
Representative examples are specifically shown in Table 4, but the present invention is not limited to the following representative examples.
Table 4
[0047]
[Table 4]

[0048]

[0049]
In addition, anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, naphthaloperinone, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bis Benzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinylanthracene, diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelated oxinoid compound, Quinacridone, rubrene, dyes, fluorescent dyes for laser and whitening, etc. Not shall.
[0050]
The light emitting material of the present invention and any of the above compounds which can be used together in the light emitting layer may be present in any ratio in the light emitting layer. That is, by the respective combinations of the above-mentioned compound and the compound of the present invention, the compound of the present invention can be a main material forming the light emitting layer or a dough pink material in another main material.
[0051]
In the light emitting layer, if necessary, in addition to the light emitting material of the present invention, further known light emitting materials, doping materials, hole injection materials and electron injection materials can be used. When the organic EL element has a multilayer structure, it is possible to prevent a decrease in luminance and life due to quenching. If necessary, a combination of a light emitting material, a doping material, a hole injection material, and an electron injection material can be used. Further, with the use of the doping material, emission luminance and emission efficiency can be improved, and red and blue light emission can be obtained. Further, each of the hole injection zone, the light emitting layer, and the electron injection zone may be formed by a layer structure of two or more layers. At that time, in the case of the hole injection zone, a layer for injecting holes from the electrode is a hole injection layer, and a layer for receiving holes from the hole injection layer and transporting holes to the light emitting layer is a hole transport layer. Call. Similarly, in the case of the electron injection zone, a layer that injects electrons from the electrode is called an electron injection layer, and a layer that receives electrons from the electron injection layer and transports electrons to the light emitting layer is called an electron transport layer. These layers are selected and used depending on factors such as the energy level of the material, heat resistance, and adhesion to the organic layer or the metal electrode.
[0052]
As a hole injecting material, it has the ability to transport holes, has a hole injecting effect from the anode, an excellent hole injecting effect on the light emitting layer or the light emitting material, and has a function of excitons generated in the light emitting layer. Compounds that prevent migration to the electron injection zone or the electron injection material and have excellent thin film forming ability are mentioned. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, imidazolethione, pyrazoline, pyrazolone, tetrahydroimidazole, oxazole, oxadiazole, hydrazone, acylhydrazone, polyaryl There are alkanes, stilbenes, butadienes, benzidine-type triphenylamines, styrylamine-type triphenylamines, diamine-type triphenylamines and the like, and derivatives thereof, and polymer materials such as polyvinylcarbazole, polysilane, and conductive polymers. However, the present invention is not limited to these.
[0053]
Among the hole injection materials that can be used in the organic EL device of the present invention, more effective hole injection materials are arylamine derivatives, phthalocyanine compounds or triphenylene derivatives. Specific examples of the arylamine derivative include triphenylamine, tolylamine, tolydiphenylamine, N, N′-diphenyl-N, N′-di-m-tolyl-4,4′-biphenyldiamine, N, N, N ', N'-tetra (p-tolyl) -p-phenylenediamine, N, N, N', N'-tetra-p-tolyl-4,4'-biphenyldiamine, N, N'-diphenyl-N, N'-di (1-naphthyl) -4,4'-biphenyldiamine, N, N'-di (4-n-butylphenyl) -N, N'-di-p-tolyl-9,10-phenanthylenediamine , 4,4 ', 4 "-tris (N-phenyl-Nm-tolylamino) triphenylamine, 1,1-bis [4- (di-p-tolylamino) phenyl] cyclohexane and the like, and aromatics thereof Tertiary amine skeleton There are oligomers or polymers, etc., but is not limited thereto.
[0054]
As an electron injection material, it has the ability to transport electrons, has the effect of injecting holes from the cathode, has an excellent electron injection effect on the light emitting layer or the light emitting material, and injects excitons generated in the light emitting layer. Compounds that prevent migration to a zone and have an excellent ability to form a thin film may be mentioned. For example, there are fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylidenemethane, anthraquinodimethane, anthrone, and derivatives thereof. However, the present invention is not limited to these. Alternatively, the electron injecting material may be sensitized by adding an electron accepting substance to the hole injecting material and the electron donating substance to the electron injecting material.
[0055]
In the organic EL device of the present invention, a more effective electron injecting material is a metal complex compound or a nitrogen-containing five-membered ring derivative. Specifically, as the metal complex compound, lithium 8-hydroxyquinolinato, bis (8-hydroxyquinolinato) zinc, bis (8-hydroxyquinolinato) copper, bis (8-hydroxyquinolinato) manganese , Tris (8-hydroxyquinolinato) aluminum, tris (2-methyl-8-hydroxyquinolinato) aluminum, tris (8-hydroxyquinolinato) gallium, bis (10-hydroxybenzo [h] quinolinato) beryllium , Bis (10-hydroxybenzo [h] quinolinato) zinc, bis (2-methyl-8-hydroxyquinolinato) chlorogallium, bis (2-methyl-8-hydroxyquinolinato) (o-cresolate) gallium, Bis (2-methyl-8-hydroxyquinolinate) (1-Naphtholar ) Aluminum, bis (2-methyl-8-hydroxyquinolinato) (2-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinato) phenolategallium, bis (o- (2-benzoxazolyl) Phenolate) zinc, bis (o- (2-benzothiazolyl) phenolate) zinc, bis (o- (2-benzotriazolyl) phenolate) zinc, and the like, but are not limited thereto.
[0056]
Since the light-emitting material of the present invention has a high glass transition point and a high melting point, resistance to Joule heat generated in an organic layer during organic electroluminescence, between organic layers or between an organic layer and a metal electrode (heat resistance) is improved. When used as an organic EL device material, it exhibits high emission luminance and is advantageous when emitting light for a long time.
[0057]
The method for forming a film of the polymer of the present invention is not particularly limited. For example, a vacuum deposition method from a powder state, a method of dissolving in a solvent, and then coating (eg, a spin coating method, a casting method, a dipping method, a bar coating method) , A roll coating method, etc.), but an application method is preferable from the viewpoint of simplification of the element manufacturing process, workability, and enlargement of the area. Examples of the solvent used when forming a film by the coating method include organic halogen solvents such as dichloroethane, dichloromethane, and chloroform; ether solvents such as tetrahydrofuran and 1.4-dioxane; and aromatic hydrocarbon solvents such as toluene and xylene. And amide solvents such as dimethylformamide and dimethylacetamide, ester solvents such as ethyl acetate and reference butyl, or a mixed solvent thereof. Although it depends on the structure and molecular weight of the polymer, the film is usually formed using a solution in which 0.01 to 10% by weight, preferably 0.1 to 5% by weight of a solvent is dissolved.
[0058]
An organic EL device is a device in which a single or multilayer organic thin film is formed between an anode and a cathode. In the case of a single layer type, a light emitting layer is provided between the anode and the cathode. The light-emitting layer contains a light-emitting material and may further contain a hole-injection material or an electron-injection material for transporting holes injected from an anode or electrons injected from a cathode to the light-emitting material. However, the light-emitting material of the present invention has a high hole-transporting capability and can form a uniform thin film. Therefore, it is possible to form a light-emitting layer using only the light-emitting material of the present invention. The multilayer type includes (anode / hole injection zone / emission layer / cathode), (anode / emission layer / electron injection zone / cathode), (anode / hole injection zone / emission layer / electron injection zone / cathode) There is an organic EL element stacked in a configuration.
[0059]
As the conductive substance used for the anode of the organic EL element, those having a work function of more than 4 eV are preferable, such as carbon, aluminum, vanadium, iron, cobalt, nickel, tungsten, silver, gold, platinum, and palladium. And alloys thereof, metal oxides such as tin oxide and indium oxide called ITO substrates and NESA substrates, and organic conductive resins such as polythiophene and polypyrrole.
As the conductive material used for the cathode, those having a work function smaller than 4 eV are preferable, and magnesium, calcium, tin, lead, titanium, yttrium, lithium, ruthenium, manganese, and the like and alloys thereof are used. However, the present invention is not limited to these. The anode and the cathode may be formed of two or more layers if necessary.
[0060]
The organic EL device of the present invention can be applied to a flat panel display such as a wall-mounted television, a light source such as a copying machine or a printer, a light source such as a liquid crystal display or an instrument, a display board, or a sign lamp as a plane light emitter. , Its industrial value is very large.
[0061]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples. In the description, parts represent parts by weight, and% represents% by weight.
Method for synthesizing compound (1) 15 parts of cyclohexanone, 24 parts of 4,4-bis (2,4-dimethylphenylphenylamino) biphenyl and 0.5 part of methanesulfonic acid were put in 15 parts of acetic acid. And stirred at 100 ° C. for 20 hours. Thereafter, the mixture was diluted with 500 parts of water and neutralized with a dilute aqueous sodium hydroxide solution. Thereafter, extraction was performed with ethyl acetate, and the mixture was concentrated and purified by column chromatography using silica gel to obtain 18 parts of a powder having white fluorescence. As a result of molecular weight analysis by GPC analysis in terms of styrene, it was confirmed that the compound was Compound (1).
FIG. 1 shows the infrared absorption spectrum (KBr tablet method) of this compound.
[0062]
Synthesis method of compound (4) In 21 parts of acetic acid, 18 parts of 4-methylcyclohexanone, 20 parts of 9,10-bis (4-n-butylphenylphenylamino) phenanthrene, and 0.5 part of methanesulfonic acid Then, the mixture was heated and stirred at 100 ° C. for 25 hours. Thereafter, the mixture was diluted with 400 parts of water and neutralized with a dilute aqueous sodium hydroxide solution. Thereafter, extraction was performed with ethyl acetate, and the mixture was concentrated and purified by column chromatography using silica gel to obtain 15 parts of a powder having white fluorescence. As a result of molecular weight analysis by GPC analysis in terms of styrene, it was confirmed to be compound (4).
[0063]
Method for synthesizing compound (10) 15 parts of 4-methylcyclohexanone, 18 parts of 1,5-bis (3,4-dimethylphenylphenylamino) naphthalene and 0.5 part of methanesulfonic acid in 30 parts of acetic acid Then, the mixture was heated and stirred at 100 ° C. for 80 hours. Thereafter, the mixture was diluted with 500 parts of water and neutralized with a dilute aqueous sodium hydroxide solution. Thereafter, extraction was performed with ethyl acetate, and the mixture was concentrated and purified by column chromatography using silica gel to obtain 7 parts of a powder having white fluorescence. As a result of molecular weight analysis by GPC analysis in terms of styrene, it was confirmed that the product was Compound (10).
[0064]
Hereinafter, examples using the light emitting material of the present invention will be described. In this example, characteristics of an organic EL element having an electrode area of 2 mm × 2 mm were measured.
Example 1
Compound (1) was dissolved and dispersed in toluene at a concentration of 2% on the washed glass plate with an ITO electrode, and a light emitting layer having a thickness of 100 nm was obtained by spin coating. An electrode having a thickness of 40 nm for Ca and 80 nm for Al was formed thereon to obtain an organic EL device. This device had a luminance of 20 cd / m ² and a luminous efficiency of 0.05 lm / W at a DC voltage of 8 V.
[0065]
Example 2
PEDOT is formed into a film having a thickness of 50 nm on a washed glass plate with an ITO electrode by spin coating, and then the compound (1) is dissolved in toluene at a concentration of 2% to form a 100 nm film by spin coating. A thick light emitting layer was obtained. An electrode having a thickness of 40 nm for Ca and 80 nm for Al was formed thereon to obtain an organic EL device. This device had a luminance of 70 cd / m ² and a luminous efficiency of 0.1 lm / W at a DC voltage of 6 V. FIG. 2 shows the emission spectrum of this device.
[0066]
Example 3
PEDOT was formed into a film having a thickness of 50 nm by spin coating on a washed glass plate with an ITO electrode, and then a polyalkylfluorene derivative represented by the compound (P-2) was added to the compound (1) in a ratio of 4: 6. Was dissolved in toluene at a concentration of 2% mixed at a ratio of 1. The light emitting layer having a thickness of 100 nm was obtained by a spin coating method. An electrode having a thickness of 40 nm for Ca and 80 nm for Al was formed thereon to obtain an organic EL device. This device had a luminance of 1500 cd / m ² and a luminous efficiency of 0.51 m / W at a DC voltage of 6 V. FIG. 3 shows the emission spectrum of this device.
[0067]
Example 4-8
PEDOT was formed into a film having a thickness of 50 nm on a washed glass plate with an ITO electrode by spin coating, and then the compound shown in Table 3 was mixed with the compound (P-2) at a ratio of 4: 6. It was dissolved in toluene at a concentration of 2%, and a light emitting layer having a thickness of 100 nm was obtained by a spin coating method. An electrode having a thickness of 40 nm for Ca and 80 nm for Al was formed thereon to obtain an organic EL device. This device obtained the emission luminance shown in Table 5 at a DC voltage of 6 V.
[0068]
Table 5
[Table 5]

[0069]
Comparative Example 1
An organic EL device of Example 2 using only the compound (P-2) for the light emitting layer was produced. This device had a luminance of about 30 cd / m ^{2 and a} luminous efficiency of 0.03 lm / W at a DC voltage of 8 V.
FIG. 4 shows the emission spectrum of this device.
[0070]
When all the organic EL elements shown in this example were continuously lit, luminance of 50% or more of the initial luminance could be observed for 1000 hours or more. However, the element of Comparative Example 1 was continuously lit under the same conditions. As a result, the brightness became 50% or less of the initial sensitivity in 10 hours, and the number of dark spots became extremely large. Since the hole transport material of the present invention has a high molecular weight, the heat resistance as an organic EL device is extremely improved. The glass transition temperatures of all the compounds of the present invention are 140 ° C. or higher, respectively, indicating that the luminescent material of the present invention is greatly improved.
The organic EL device of the present invention achieves improvement in luminous efficiency, luminous luminance and long life, and is used together with a luminescent substance, a luminescent auxiliary material, a hole transport material, an electron transport material, a sensitizer, It does not limit the resin, the electrode material and the like, and the element manufacturing method.
[0071]
【The invention's effect】
According to the present invention, a white organic EL device having higher luminous efficiency and higher luminance than the conventional one and having a long service life can be obtained.
[Brief description of the drawings]
FIG. 1 is an infrared absorption spectrum of compound (1). FIG. 2 is an emission spectrum of the device of Example 2. FIG. 3 is an emission spectrum of the device of Example 3. FIG. 4 is a device of Comparative Example 1. Emission spectrum diagram of

Claims (4)

A light emitting material for an organic electroluminescence device represented by the following general formula [1].
General formula [1]

[Wherein A represents the following general formula [2] or general formula [3]:
B represents a non-aromatic 2 to 20 membered ring which may contain an oxygen atom, a sulfur atom, a selenium atom, or a nitrogen atom;
R ^a and R ^b represent a hydrogen atom or an alkyl group which may be substituted,
n shows the integer of 1 or more and 5000 or less, respectively. ]
General formula [2]

[Wherein R ¹ and R ⁴ are monovalent phenyl groups, and are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group , Amino group, mono- or di-substituted amino group, hydroxyl group, Mercart group, substituted or unsubstituted aryloxy group, substituted or unsubstituted arylthio group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted heterocyclic ring Represents a monovalent phenyl group which may be substituted with a group,
R ² and R ^{3 each} represent a divalent phenyl group, and include a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group, and an amino group. , Substituted with a mono- or di-substituted amino group, hydroxyl group, mercart group, substituted or unsubstituted aryloxy group, substituted or unsubstituted arylthio group, substituted or unsubstituted aromatic ring group, substituted or unsubstituted heterocyclic group Represents a divalent phenyl group which may be
In addition, the substituents of R ^{1 to} R ⁴ may form a substituted or unsubstituted ring with adjacent substituents. X is a divalent aromatic ring residue or -Ar-Z-Ar-
(Ar is an aromatic ring residue having 6 to 20 carbon atoms,
Z represents a direct bond, an oxygen atom, a sulfur atom, a selenium atom, a divalent aromatic ring residue which may contain these atoms, or a divalent aliphatic residue which may contain these atoms. Represent. )
Is shown. ]
General formula [3]

[Wherein R ⁶ and R ⁷ are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group, an amino group, a mono- or di-substituted amino group; A monovalent group which may be substituted with a group, a hydroxyl group, a Mercart group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted aromatic ring group, or a substituted or unsubstituted heterocyclic group Represents a phenyl group,
R ⁵ and R ⁸ are a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted thioalkoxy group, a cyano group, an amino group, a mono- or di-substituted amino group, a hydroxyl group A mervalent group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted aromatic ring group, a divalent phenyl group which may be substituted with a substituted or unsubstituted heterocyclic group Represents
Further, the substituents of R ^{5 to} R ⁸ may form a substituted or unsubstituted ring with adjacent substituents. X is a divalent aromatic ring residue or -Ar-Z-Ar-
(Ar is an aromatic ring residue having 6 to 20 carbon atoms,
Z represents a direct bond, an oxygen atom, a sulfur atom, a selenium atom, a divalent aromatic ring residue which may contain these atoms, or a divalent aliphatic residue which may contain these atoms. Represent. )
Is shown. ] The light emitting material according to claim 1, which is an organic electroluminescent device further comprising a conjugated polymer. 3. The luminescent material for an organic electroluminescent device according to claim 1, wherein the luminescent material is white. In an organic electroluminescence device formed by forming a light emitting layer or a plurality of organic compound thin films including a light emitting layer between a pair of electrodes, the light emitting layer contains the light emitting material according to any one of claims 1 to 3 alone or as a mixture. An organic electroluminescence device characterized by the above-mentioned.

Images