JP2004292766A - Organic electroluminescent element material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an organic electroluminescent element material which can easily form a thin film by a spin coating method and is of high purity. <P>SOLUTION: This organic electroluminescent element material comprises a compound which has a framework of a cyclic aryl ether or cyclic aryl sulfide, wherein the framework is bound directly or at least through a two valent organic group with a luminous or charge transporting organic group derived from an illuminant or charge transporter known as an organic electroluminescent element material, and is shown e.g. by formula 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２２】
ここで、上記式（１）中のＡｒ^１及びＡｒ^２はそれぞれ独立に芳香族炭化水素基であり、当該芳香族炭化水素基としては炭素数６〜２０の芳香族炭化水素基が好適であり、その具体例としてはフェニル基、ナフチル基、トリル基、キシリル基等を挙げることができる。また、前記式（１）中のＸ^１及びＸ^２は、それぞれ独立には酸素原子又は硫黄原子を意味する。
【００２３】
また、前記式（１）中のＡ^１及びＡ^２はそれぞれ独立にハロゲン原子、アルキル基、アリール基、アルコキシ基または下記式（２）で示される基である。
【００２４】
−（Ｏ）_ｌ−（Ｙ）_ｍ−Ｚ （２）
Ａ^１又はＡ^２としてのハロゲン原子としては、フッ素原子、塩素原子、臭素原子、ヨウ素原子を挙げることができる。また、アルキル基としては、メチル基、エチル基、プロピル基、ブチル基等の炭素数１〜４の基が好適であり、アリール基としては、フェニル基、トリル基、キシリル基、ナフチル基等の炭素数６〜１０の基が好適であり、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、ブトキシ基、２−エチルヘキシルオキシ基等の炭素数１〜８の基を好適に使用することができる。なお、式（２）については、後で詳しく説明する。
【００２５】
また、前記式（１）において、ｘは０〜１０、好適には０〜４の整数であり、ｙは０〜１０、好適には０〜４の整数であり、ｘとｙとが同時に０になることはなく、ｚは１〜２０、好適には１〜１０の整数であり、ｎ１及びｎ２はそれぞれ０〜８、好適には０〜４の整数である。即ち、ｘ＝０〜４、ｙ＝０〜４、ｚ＝１〜１０、ｎ１＝０〜２で且つｎ２＝０〜２であるのが好ましい。
【００２６】
更に、前記式（１）で示される化合物においては、分子中に存在するＡ^１及びＡ^２の内の少なくとも１つは前記式（２）で示される基である必要がある。したがって、前記ｎ１とｎ２とが同時に０になることはない。さらにまた、同一のＡｒ^１にＡ^１が複数結合する場合、当該複数存在結合するＡ^１は互いに異なっていてもよく、同一のＡｒ^２にＡ^２が複数結合する場合、当該複数存在結合するＡ^２はそれぞれ互いに異なっていてもよい。
【００２７】
また、前記式（２）において、Ｏは酸素原子を、Ｙは２価の有機基を、Ｚは発光性有機基または電荷輸送性有機基を意味し、更にｌおよびｍはそれぞれ独立に０または１を意味する。
【００２８】
前記式（２）におけるＹで示される２価の有機基としては、発光性有機基または電荷輸送性有機基と環状アリールエーテル誘導体及び環状アリールスルフィド誘導体とを連結し得る基であれば何ら制限されない。基−Ｙ−の好適な例としては下記式で示される基を挙げることができる（ただし、式中のＲはアルキル基を意味し、ｎは０〜２０の整数を意味する。）。
【００２９】
【化１３】

【００３０】
また、前記式（２）におけるＺで示される発光性有機基および電荷輸送性有機基としては、前記したような公知の発光体、電荷輸送体を骨格として有する残基を何ら制限なく用いることができる。Ｚとして好適な発光性有機基および電荷輸送性有機基の具体例を以下に示す。
【００３１】
〔Ｉ．発光性有機基〕
（Ｉ−１）一重項発光性有機基
【００３２】
【化１４】

【００３３】
【化１５】

【００３４】
（式中、ｐおよびｑはそれぞれ１〜１０の整数であり、且つ各発光性有機基の数平均分子量が２００〜４０００の範囲の値をとるような整数である。）
（Ｉ−２）三重項発光性有機基
【００３５】
【化１６】

【００３６】
〔ＩＩ．電荷輸送性有機基〕
（ＩＩ−１）正孔輸送性有機基
【００３７】
【化１７】

【００３８】
【化１８】

【００３９】
（ＩＩ−２）電子輸送性有機基
【００４０】
【化１９】

【００４１】
【化２０】

【００４２】
【化２１】

【００４３】
なお、下記式（１）で示す環状アリールエーテル誘導体または環状アリールスルフィド誘導体のうち発光性有機基および電荷輸送性有機基がそれぞれ上記（Ｉ）および（ＩＩ）で示す基である化合物は新規化合物である。
【００４４】
本発明において好適に用いられるカリックス誘導体を具体的に例示すれば、次のとおりである。
【００４５】
【化２２】

【００４６】
【化２３】

【００４７】
【化２４】

【００４８】
【化２５】

【００４９】
本発明で用いる環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は、ガラス転移温度が比較的高くて熱的安定性が高い。ガラス転移温度は変動するが、概ね１００℃前後である。このため、これら環状アリールエーテル誘導体及び環状アリールスルフィド誘導体を有機ＥＬ素子材料として利用したとき、駆動電圧をかけた際に発生する熱量を抑えることができる。このような熱的安定性は、環状アリールエーテル誘導体及び環状アリールスルフィド誘導体が環状構造を有していることによるものであると考えられる。また、環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は可視領域に吸収を持たない。このため、環状アリールエーテル誘導体及び環状アリールスルフィド誘導体を用いた有機ＥＬ素子材料は、エネルギー移動等により発光効率が低下することを有効に抑えることができる。
【００５０】
これら環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は、それぞれ単独で有機ＥＬ素子材料として使用できるが、異なる種類のものを混合して使用することもできる。さらに、発光性有機基を有する環状アリールエーテル誘導体または環状アリールスルフィド誘導体（総称して発光性誘導体ともいう）と電荷輸送性有機基を有する環状アリールエーテル誘導体または環状アリールスルフィド誘導体（総称して電荷輸送性誘導体ともいう）とを混合して有機ＥＬ素子材料として用いることができる。この場合、発光性誘導体と電荷輸送誘導体の配合割合は、特に制限されないが、一般には発光性誘導体１００重量部に対して電荷輸送誘導体を０．１〜９９．９重量部の範囲で配合することが好ましく、さらに１〜９９重量部の範囲とすることがより好ましい。
【００５１】
本発明で使用する環状アリールエーテル誘導体及び環状アリールスルフィド誘導体の製造方法は特に制限されず、通常利用される合成法を適宜組み合わせることによって製造することができる。好ましい合成法として、以下のスキームに示す合成法を例示することができる。
【００５２】
環状アリールエーテル誘導体及び環状アリールスルフィド誘導体の合成においては、環状アリールエーテル構造部分または環状アリールスルフィド構造部分と発光性有機基および電荷輸送性有機基の部分とを結合する際に、連結基を介さず直接結合する有用な反応例としては、例えば、下記（１）〜（３）の反応等を挙げることができる。
【００５３】
（１）ハロゲン化アリールまたはトリフリルアリールとボロン酸をＰｄ（０価）、炭酸ナトリウムの触媒存在下でカップリングさせるＳｕｚｕｋｉ Ｃｏｕｐｌｉｎｇ反応、
（２）ハロゲン化アリールと塩化亜鉛アリールをＰｄ（０価）、Ｎｉ（０価）の触媒存在下でカップリングさせるＮｅｇｉｓｈｉ Ｃｏｕｐｌｉｎｇ反応 及び
（３）ハロゲン化アリール同士をＣｕ触媒存在下でカップリングさせるＵｌｌｍａｎｎ Ｃｏｕｐｌｉｎｇ反応。
【００５４】
また、連結基を介して結合する反応としては、例えば、下記（１）〜（５）の反応等を挙げることができる。
【００５５】
（１）カルボン酸とアミンを反応させ、アミド結合を形成する反応、
（２）クロロメチル基とアミンとの反応、
（３）リンイリドとカルボニル基を反応させ二重結合を形成するＷｉｔｔｉｇ反応、
（４）リン酸エステルとカルボニル基を反応させ、二重結合を形成する反応および
（５）グリニア試薬とハロゲン化合物を反応させて、炭素−炭素結合を形成する反応。
【００５６】
さらに、合成した環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は、再結晶またはカラムクロマトグラフィーにより精製される。再結晶に用いる溶媒としては、公知の有機溶媒、それらの混合溶媒が用いられるが、好ましくはエタノール、イソプロピルアルコール、アセトン、酢酸エチル、アセトニトリル、ヘキサン、ヘプタン、トルエンが使用される。
【００５７】
上記の製造方法によれば、環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は容易に精製して単離することが可能である。したがって、不純物の濃度が比較的高くて分子量分布がある通常のポリマー材料に比べると、環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は有機ＥＬ素子材料としての利用価値が高い。上述のように、本発明における発光性有機基を有する環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は発光層を形成する発光体として、また、電荷輸送性有機基を有する環状アリールエーテル誘導体及び環状アリールスルフィド誘導体は電荷輸送層を形成する電荷輸送体として極めて有用である。
【００５８】
本発明の有機ＥＬ素子材料を用いて作成される有機ＥＬ素子の構造については、少なくとも一方が透明または半透明である一対の電極間に、本発明の有機ＥＬ素子材料を含む発光層もしくは電荷輸送層が形成されておれば特に制限されず、公知の構造を採用することができる。例えば、発光体のみからなる発光層もしくは発光体と電荷輸送体との混合物からなる発光層の両面に少なくとも一方が透明または半透明の電極である一対の電極を有する構造のもの、このような構造において更に陽極と発光層の間に正孔輸送体を含む正孔輸送層および陰極と発光層の間に電子輸送体を含む電子輸送層を積層したものを挙げることができる。
【００５９】
また、発光層や電荷輸送層は各層が複数の化合物からなっても良い。例えば、発光層において、ある発光体に他の発光体を混ぜることにより、ある発光体から他の発光体へエネルギー移動を生じさせ、他の発光体から効率よく発光させることができる。このような機能を有する他の発光体は、ドーパント材料と呼ばれる。この時混合する化合物及びその数は特に制限はなく、本発明の有機ＥＬ素子材料及び又は公知の発光体が使用でき、ある発光体と発光させる他の発光体とのエネルギー関係において、最適になるように化合物を組み合わせればよい。また他の発光体の濃度はある発光体との合計量中、０．１〜５０重量％の範囲で選択される。また電荷輸送層においては、電極からの電荷注入障壁または素子の電荷注入バランスをとることを目的として、複数の化合物を混合することができる。混合する化合物数は特に制限はなく、さらに添加濃度も前述の発光体の場合と同様に合計量中に占める割合で他の化合物を０．１〜５０重量％の範囲で用いることができる。さらに、複数の発光体及び複数の電荷輸送体を混合した発光層とすることもできる。
【００６０】
また、発光層や電荷輸送層は１層であってもよく、また、複数の層を組み合わせることもできる。さらに、発光層に本発明の有機ＥＬ素子材料以外の発光体を混合使用することもでき、電荷輸送層に本発明の有機ＥＬ素子材料以外の電荷輸送体を混合使用することもできる。また、発光層および電荷輸送層は、本発明の有機ＥＬ素子材料単独で構成されていてもよく、中分子あるいは高分子化合物に分散させて構成してもよい。
【００６１】
本発明の有機ＥＬ素子材料と共に使用できる公知の発光体（ドーパント材として機能するものを含む）としては特に限定されないが、前述した発光性有機基に表されるような化合物、例えば、ジスチリルアリーレン誘導体、スチリルアミン誘導体、ナフタレン誘導体、アントラセンもしくはその誘導体、ペリレンもしくはその誘導体、ポリメチン系、キサンテン系、クマリン系、シアニン系などの色素類、８−ヒドロキシキノリンもしくはその誘導体の金属錯体、ユーロピウムあるいはイリジウムを含む三重項発光性の金属錯体、芳香族アミン、テトラフェニルシクロペンタジエンもしくはその誘導体、またはテトラフェニルブタジエンもしくはその誘導体、ポリ（９，９ジアルキルフルオレン）誘導体、ポリパラフェニレン誘導体等のアリーレン誘導体のπ共役系高分子化合物、ポリチオフェン誘導体等のπ共役系高分子化合物、ポリパラフェニレンビニレン誘導体等のアリーレンビニレン誘導体のπ共役系高分子化合物、などを用いることができる。具体的には、例えば特開昭５７−５１７８１号、同５９−１９４３９３号公報に記載されているもの等、公知のものが使用可能である。
【００６２】
また、上記した本発明の有機ＥＬ素子材料と共に使用できる公知の電荷輸送体を例示すれば、正孔輸送体としてはピラゾリン誘導体、アリールアミン誘導体、スチルベン誘導体、トリフェニルジアミン誘導体などを挙げることができ、電子輸送体としてはオキサジアゾール誘導体、アントラキノジメタンもしくはその誘導体、テトラシアノアンスラキノジメタンもしくはその誘導体、フルオレノン誘導体、ジフェノキノン誘導体、または８−ヒドロキシキノリンもしくはその誘導体の金属錯体などを挙げることができる。
【００６３】
これらの化合物の具体例は、特開昭６３―７０２５７号、同６３−１７５８６０号公報、特開平２−１３５３５９号、同２−１３５３６１号、同２−２０９９８８号、同３−３７９９２号、同３−１５２１８４号公報に記載されている。
【００６４】
上記した電荷輸送体の中でも正孔輸送体としては、トリフェニルジアミン誘導体、電子輸送体としてはオキサジアゾール誘導体、または８−ヒドロキシキノリンもしくはその誘導体の金属錯体が好ましく、特に、正孔輸送体としては、４，４’−ビス（Ｎ（３−メチルフェニル）−Ｎ−フェニルアミノ）ビフェニルが、電子輸送体としては２−（４−ｔ−ブチルフェニル）−１，３，４−オキサジアゾ−ル、ベンゾキノン、アントラキノン、トリス（８−キノリノール）アルミニウムが好ましい。
【００６５】
これらのうち、正孔輸送体と電子輸送体のいずれか一方、または両方を同時に使用することができる。これらの各材料は一種を用いてもよいし、２種以上を組み合わせて用いてもよい。発光層と電極の間に電荷輸送層を設ける場合、上記で説明した電荷輸送体を使用して電荷輸送層を形成すればよい。
【００６６】
また、電荷輸送体を発光層に混合して使用する場合、電荷輸送体の使用量は使用する化合物の種類などによっても異なるので、十分な成膜性と発光特性を阻害しない範囲でそれらを考慮して適宜決めればよい。通常、発光体に対して１〜４０重量％が好ましく、さらに好ましくは２〜３０重量％である。
【００６７】
これらのうち、正孔輸送体と電子輸送体のいずれか一方、または両方を同時に使用することができる。これらの各材料は一種を用いてもよいし、２種以上を組み合わせて用いてもよい。発光層と電極の間に電荷輸送層を設ける場合、上記で説明した電荷輸送体を使用して電荷輸送層を形成すればよい。
【００６８】
また、電荷輸送体を発光層に混合して使用する場合、電荷輸送体の使用量は使用する化合物の種類などによっても異なるので、十分な成膜性と発光特性を阻害しない範囲でそれらを考慮して適宜決めればよい。通常、発光体に対して１〜４０重量％が好ましく、さらに好ましくは２〜３０重量％である。
【００６９】
次に、本発明の有機ＥＬ素子材料を用いた有機ＥＬ素子の代表的な作製方法について述べる。まずは、ガラス、透明プラスチック等の透明基板の上に透明または半透明な金属酸化物あるいは金属薄膜を用いて陽極を形成する。その材料としては、導電性の金属酸化物膜、半透明の金属薄膜等が用いられる。具体的にはインジウム・スズ・オキサイド（ＩＴＯ）、酸化スズ等からなる導電性ガラスを用いて作成された膜（ＮＥＳＡなど）、Ａｕ、Ｐｔ、Ａｇ、Ｃｕ等が用いられる。作製方法としては真空蒸着法、スパッタリング法、メッキ法などが用いられる。
【００７０】
次にこの陽極上に、本発明の有機ＥＬ素子材料を含む発光層を形成する。形成方法としては、これら材料の溶融液、溶液または混合液を使用するスピンコーティング法、キャスティング法、ディッピング法、バーコード法、ロールコート法、グラビアコート法、フレキソ印刷法、スプレーコート法、インクジェット印刷法などの塗布法により成膜することが特に好ましい。
【００７１】
発光層の膜厚としては、好ましくは１ｎｍ〜１μｍ、さらに好ましくは２〜５００ｎｍである。電流密度を上げて発光効率を上げるためには５〜２００ｎｍの範囲が好ましい。なお、塗布法により薄膜化した場合には、好ましくは溶媒を除去するため、減圧下または不活性雰囲気下、好ましくは３０〜３００℃、さらに好ましくは６０〜２００℃の温度で加熱乾燥することが望ましい。
【００７２】
また、電荷注入効率を向上させるために発光層と電荷輸送層とを積層する場合には、陽極の上に本発明の正孔輸送性を示す電荷輸送層を上述と同様の製膜方法で形成するかあるいは公知の正孔輸送体を公知の方法で形成し、その後本発明の有機ＥＬ素子材料の発光層を上述した製膜方法で形成し、その上に本発明の電子輸送性を示す電荷輸送層を上述と同様の製膜方法で形成するかあるいは公知の電子輸送体を公知の方法で形成する。
【００７３】
公知の電荷輸送体の成膜方法としては、特に限定されないが、粉末状態からの真空蒸着法、または溶液に溶かした後のスピンコーティング法、キャスティング法、ディッピング法、バーコード法、ロールコート法などの塗布法を使用できる。
【００７４】
電荷輸送層の厚さについては、少なくともピンホールが発生しないような厚さが必要であるが、あまり厚いと、素子の抵抗が増加し、高い駆動電圧が必要となり好ましくない。したがって、電荷輸送層の厚さは、好ましくは１ｎｍ〜１μｍ、さらに好ましくは２ｎｍ〜５００ｎｍ、特に好ましくは５ｎｍ〜２００ｎｍである。
【００７５】
次いで、陰極を設ける。この電極は電子注入陰極となる。その材料としては、特に限定されないが、イオン化エネルギーの小さい材料が好ましい。例えば、Ａｌ、Ｉｎ、Ｍｇ、Ｃａ、Ｌｉ、Ｍｇ−Ａｇ合金、Ｉｎ−Ａｇ合金、Ｍｇ−Ｉｎ合金、Ｍｇ−Ａｌ合金、Ｍｇ−Ｌｉ合金、Ａｌ−Ｌｉ合金、Ａｌ−Ｃａ合金、グラファイト薄膜等が用いられる。陰極の作製方法としては真空蒸着法、スパッタリング法等が用いられる。
【００７６】
【実施例】
以下に実施例を記載して本発明をさらに具体的に説明するが、本発明はこれらの実施例に限定されるものではない。
【００７７】
実施例１
【００７８】
【化２６】

で示す化合物と
【００７９】
【化２７】

で示す化合物とをテトラヒドロフラン中、ｔ−ブトキシカリウムの存在下で反応させ、目的物を得た（収率３３％）。分子量分析（ＴＯＦ−ＭＳ）によりＭ＋２８７６を確認した。表１に結果を示した。さらに元素分析（表１１）および^１Ｈ−核磁気共鳴スペクトル（^１Ｈ−ＮＭＲ）測定を行い、化合物の構造を確認した。
【００８０】
実施例２〜６
表１〜３に示した原料を用いた他は実施例１と同様の方法でＡＥ−２〜ＡＥ−６を合成した。結果を表１〜３および表１４に示した。
【００８１】
実施例７
【００８２】
【化２８】

で示す化合物と
【００８３】
【化２９】

で示す化合物とを酢酸パラジウム、トリス（ｔ−ブチル）ホスフィン、ｔ−ブトキシナトリウムの存在下、キシレン中で反応させ目的物（ＡＥ−７）を得た（収率１８％）。分子量分析（ＴＯＦ−ＭＡＳＳ）によりＭ^＋２５８３を確認した。表４に結果を示した。さらに元素分析（表１４）および^１Ｈ−核磁気共鳴スペクトル（^１Ｈ−ＮＭＲ）測定を行い、化合物の構造を確認した。
【００８４】
実施例８
表４に示した原料を用いた他は実施例７と同様にして有機ＥＬ素子材料ＡＥ−８を合成した。結果を表４及び表１４に示した。
【００８５】
実施例９
【００８６】
【化３０】

で示す化合物と
【００８７】
【化３１】

で示す化合物とをテトラキストリフェニルホスフィンＰｄ（０価）、炭酸ナトリウムの存在下、ジメトキシエタン／ＥｔＯＨ混合溶媒中で反応させ目的物（ＡＥ−９）を得た（収率５％）。分子量分析（ＬＣ−ＭＳ）によりＭ^＋２７７１を確認した。表５に結果を示した。さらに元素分析（表１１）および^１Ｈ−核磁気共鳴スペクトル（^１Ｈ−ＮＭＲ）測定を行い、化合物の構造を確認した。
【００８８】
実施例１０
表５に示した原料を用いた他は実施例９と同様にして有機ＥＬ素子材料ＡＥ−１０を合成した。結果を表５及び表１４に示した。
【００８９】
実施例１１〜１５
表６〜８に示した原料を用いた他は実施例７と同様にして有機ＥＬ素子材料ＡＥ−１１〜ＡＥ−１５を合成した。結果を表６〜８及び表１４に示した。
【００９０】
実施例１６〜２３
表８〜１２に示した原料を用いた他は実施例９と同様にして有機ＥＬ素子材料ＡＥ−１６〜ＡＥ−２３を合成した。結果を表８〜１２及び表１５に示した。
【００９１】
実施例２４
表１２に示した環状アリールエーテル誘導体と発光体とをクロロホルム中で反応させることにより目的物を得た（収率１２％）。結果を表１２および表１５に示した。
【００９２】
実施例２５〜２６
表１３に示した原料を用いた他は実施例１と同様の方法でＡＥ−２５〜２６を合成した。結果を表１３および表１５に示した。
【００９３】
【表１】

【００９４】
【表２】

【００９５】
【表３】

【００９６】
【表４】

【００９７】
【表５】

【００９８】
【表６】

【００９９】
【表７】

【０１００】
【表８】

【０１０１】
【表９】

【０１０２】
【表１０】

【０１０３】
【表１１】

【０１０４】
【表１２】

【０１０５】
【表１３】

【０１０６】
【表１４】

【０１０７】
【表１５】

【０１０８】
実施例２７（製膜特性）
実施例１で得られた有機ＥＬ素子材料を、クロロホルムに溶解し１重量％クロロホルム溶液とした。この溶液約２ｇをＭＩＫＡＳＡ製スピンコーター１Ｈ−ＤＸ２を用いて、厚さ２ｍｍのガラス表面に、回転数４０ｒ．ｐ．ｍで１０秒→５００ｒ．ｐ．ｍで２秒→２０００ｒ．ｐ．ｍで４５秒の条件でスピンコートした。さらにこのスピンコートされたガラスを８０℃にて加熱し溶媒を除去して薄膜を形成した。
形成された薄膜を光学顕微鏡を用いて観察したが結晶は確認されなかった。さらにＸ線回折法にてこの薄膜の結晶性を評価したが、結晶反射は得られなかった。以上から、実施例１の化合物を薄膜化したものはアモルファス性を示し良好な製膜性を与えることがわかった。同様にして実施例２〜２６の有機ＥＬ材料の製膜性を評価したところ、いずれも良好なアモルファス性を示す薄膜が得られた。
【０１０９】
実施例２８（蛍光発光特性及びＥＬ発光特性）
蛍光発光特性の確認： 実施例２７で得られたＡＥ−１のスピンコートした薄膜について、３５０ｎｍに主極大を有する紫外線光を照射したところ、青色の蛍光を確認した。それを分光光度計（瞬間マルチチャンネルフォトディテクターＭＣＰＤ１０００：大塚電子製）を用いて測定したところ、４７０ｎｍに発光極大を示すスペクトルが得られた。
【０１１０】
ＥＬ発光特性評価： ２．５ｍｍ×２０ｍｍ×０．８ｍｍのガラス基板上にＩＴＯ膜を１５０ｎｍの厚さで製膜したものを透明支持基盤とした。この透明支持基盤をエッチング、洗浄後、前述したＡＥ−１の１重量％クロロホルム溶液約２ｇをＭＩＫＡＳＡ製スピンコーター１Ｈ−ＤＸ２を用いて、厚さ２ｍｍのガラス表面に、回転数４０ｒ．ｐ．ｍで１０秒→５００ｒ．ｐ．ｍで２秒→２０００ｒ．ｐ．ｍで４５秒の条件でスピンコートした。さらに８０℃にて窒素雰囲気下で加熱し溶媒を除去して薄膜を形成した。その上に、ホールブロック層としてＢＣＰ（２，９−ジメチル−４，７−ジフェニル−１，１０フェナントロリン）を２０ｎｍ、電子輸送層としてトリス（８−キノリノール）アルミニウム５０ｎｍを、ＵＬＶＡＣ製（ＥＢＶ−６ＤＡ）の蒸着装置を用いて０．１ｎｍ／秒の蒸着速度で蒸着した。最後に、その上に陰極として、アグネシウム：銀＝１０：１を１００ｎｍ蒸着し、有機ＥＬ素子を作成した。蒸着のときの真空度は、すべて１×１０^−５Ｔｏｒｒ以下であった。この素子に１２Ｖの電圧を印加し、分光光度計（瞬間マルチチャンネルフォトディテクターＭＣＰＤ１０００：大塚電子製）を用いて蛍光発光を測定したところ、４７０ｎｍに最大発光波長を有する青色の蛍光が観察された。
【０１１１】
実施例２９
実施例１で得られたＡＥ−１を１重量％およびＮ，Ｎ‘−ビス（３−メチルフェニル）−Ｎ，Ｎ’−ジフェニル−［１，１‘−ビフェニル］−４，４’−ジアミンを０．５重量％の濃度でクロロベンゼンに溶解させコート溶液を調整した。２５ｍｍ×１０ｍｍ×０．７ｍｍのガラス基板上にＩＴＯ膜を１５０ｎｍの厚さで製膜したものを透明支持基盤とし、この透明支持基盤をエッチング、洗浄後、上記で調整したコート溶液約０．４ｇをＭＩＫＡＳＡ製スピンコーター１Ｈ−Ｄ７を用いて、ガラス基板表面に回転数１５００ｒｐｍで６０秒間スピンコートした。この基板を窒素雰囲気下で１００℃に加熱して溶媒を除去し、薄膜を形成した。更に、アルバック製真空蒸着装置ＥＢＶ−６ＤＡを用い、陰極としてカルシウムを４０ｎｍ、次いでアルミニウムを６０ｎｍ蒸着し有機ＥＬ素子を作成した。蒸着のときの真空度は、１×１０^−６Ｔｏｒｒ以下であった。この素子に直流電圧を印加したところ、１２．５Ｖにおいて発光輝度５５０ｃｄ／ｍ^２の青色の面発光を得た。この発光を分光光度計（瞬間マルチチャンネルフォトディテクターＭＣＰＤ１０００：大塚電子製）を用いて測定したところ、最大発光波長は４７０ｎｍであった。結果を表１６に示した。
【０１１２】
【表１６】

【０１１３】
実施例３０〜４４
表１６に示す有機ＥＬ材料を用いた以外は実施例２９と同様してＥＬ特性を評価した。結果を表１６に示した。
【０１１４】
実施例４５
ＡＥ−１とＡＥ−１１との混合物（重量比８０／２０）を１重量％の濃度でキシレンに溶解させコート溶液を調整した。２５ｍｍ×１０ｍｍ×０．７ｍｍのガラス基板上にＩＴＯ膜を１５０ｎｍの厚さで製膜したものを透明支持基盤とし、この透明支持基盤をエッチング、洗浄後、上記で調整したコート溶液約０．４ｇをＭＩＫＡＳＡ製スピンコーター１Ｈ−Ｄ７を用いて、ガラス基板表面に回転数１５００ｒｐｍで６０秒間スピンコートした。この基板を窒素雰囲気下で１００℃に加熱して溶媒を除去し、薄膜を形成した。更に、アルバック製真空蒸着装置ＥＢＶ−６ＤＡを用い、陰極としてカルシウムを４０ｎｍ、次いでアルミニウムを６０ｎｍ蒸着し有機ＥＬ素子を作成した。蒸着のときの真空度は、１×１０^−６Ｔｏｒｒ以下であった。この素子に直流電圧を印加したところ、１２．５Ｖにおいて発光輝度１４００ｃｄ／ｍ^２の青色の面発光を得た。この発光を分光光度計（瞬間マルチチャンネルフォトディテクターＭＣＰＤ１０００：大塚電子製）を用いて測定したところ、最大発光波長は４７０ｎｍであった。結果を表１７に示した。
【０１１５】
実施例４６〜６１
表１７に示す組成比で各有機ＥＬ材料を混合した以外は、実施例４５と同様にしてＥＬ特性を評価した。結果を表１７に示した。
【０１１６】
【表１７】

【０１１７】
実施例６２
ＡＥ−１とドーパアントとしてのＡＤＳ１２９ＢＥ（アメリカンダイソース社製）との混合物（重量比９０／１０）を２重量％の濃度でキシレンに溶解させ、コート溶液を調製した。
【０１１８】
２５ｍｍ×１０ｍｍ×０．７ｍｍのガラス基板上にＩＴＯ膜を１５０ｎｍの厚さで製膜したものを透明支持基盤とし、この透明支持基盤をエッチング、洗浄後、ポリエチレンジオキシチオフェン（ＰＥＤＴ）とポリスチレンスルホン酸（ＰＳＳ）の１．５６％水溶液であるバイトロンＰ（商品名：バイエル社製）をＭＩＫＡＳＡ製スピンコーター１Ｈ−Ｄ７を用いて回転数１０００ｒｐｍで６０秒間スピンコートした。この基板をホットプレート用い２００℃で１時間加熱した。この基板上に上記で調整したコート溶液約０．４ｇを回転数４０００ｒｐｍで３０秒間スピンコートし、窒素雰囲気下で１００℃に加熱して溶媒を除去し、薄膜を形成した。更に、アルバック製真空蒸着装置ＥＢＶ−６ＤＡを用い、陰極としてカルシウムを４０ｎｍ、次いでアルミニウムを８０ｎｍ蒸着し有機ＥＬ素子を作成した。蒸着のときの真空度は、１×１０^−６Ｔｏｒｒ以下であった。この素子に直流電圧を印加したところ、１２．５Ｖにおいて発光輝度２６００ｃｄ／ｍ^２の青色の面発光を得た。この発光を分光光度計（瞬間マルチチャンネルフォトディテクターＭＣＰＤ１０００：大塚電子製）を用いて測定したところ、最大発光波長は４５０ｎｍであった。結果を表１８に示した。
【０１１９】
【表１８】

【０１２０】
実施例６３
ドーパント材料としてＡＤＳ１２９ＢＥのかわりにＡＤＳ１２８ＧＥ（アメリカンダイソース社製）を用いた以外は実施例６２と同様の操作を行った。結果を表１８に示した。
【０１２１】
【発明の効果】
本発明の有機ＥＬ素子材料は、スピンコートが可能であり容易に成膜できる。また、本発明によれば、有機ＥＬ素子材料を容易に高純度で得ることができる。したがって、本発明の有機ＥＬ素子材料は、有機ＥＬ素子を構成する発光体および電荷輸送体として極めて有用である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel organic electroluminescent device material (hereinafter, referred to as “organic EL device material”).
[0002]
[Prior art]
Organic EL elements are expected to be used as inexpensive large-area, full-color display elements of the solid-state emission type, and are being actively developed at present. In general, an organic EL element has a structure in which an organic layer containing an organic light emitting material is sandwiched between a pair of counter electrodes, and by applying a potential difference between both electrodes, electrons and positive electrons are applied to the light emitting material in the organic layer. Holes are injected and light is emitted by recombining them. The organic layer generally has a laminated structure in which a light emitting layer is provided between an electron transport layer and a hole transport layer, but depending on the type of light emitting material, the light emitting layer also serves as an electron transport layer or a hole transport layer. (See Patent Document 1).
[0003]
On the other hand, organic light-emitting materials include low-molecular materials such as copper phthalocyanine (CuPc) and star-burst molecules and high-molecular materials such as poly (p-phenylenevinylene) (PPV) and polyaniline (PANI). Is known (see Non-Patent Document 1).
[0004]
[Patent Document 1]
Patent No. 2851185
[Non-patent document 1]
Katsumi Yoshino and Akihiko Fujii, "Technology Development Trend of EL Display", Electronics Technology, 2002, No. 7, p. 12-16
[0005]
[Problems to be solved by the invention]
However, there are some inconveniences and problems in thinning these materials for use as devices. That is, a vacuum evaporation method is used to form an organic thin film using a low molecular material such as CuPc and a starburst molecule, but this method has a problem that it takes time and costs. Further, the organic thin film formed by the vacuum evaporation method is easily crystallized, which leads to device deterioration.
[0006]
On the other hand, mainly in the case of polymer materials, thinning by a spin coating method is possible, so that large-capacity thinning can be performed easily and inexpensively in a short time. The use of a polymer material also has the advantage that crystallization hardly occurs. However, since the polymer has a large molecular weight distribution, a difference in light emission characteristics may be observed depending on the degree of polymerization, and there is a disadvantage that an individual difference is relatively large. Further, in PPV, since it is itself insoluble in an organic solvent, it is necessary to further heat after forming a precursor thin film, and the influence of the polymerization rate, the desorbed hydrochloric acid, etc. is a problem. . Since PANI also does not dissolve alone in organic solvents, camphorsulfonic acid must be used. As described above, an organic EL device material that can be easily formed into a thin film by spin coating and has high purity has not been provided.
[0007]
Therefore, an object of the present invention is to solve these problems of the prior art, that is, to provide a high-purity organic EL device material that can be spin-coated.
[0008]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, by bonding a cyclic aryl ether derivative or a cyclic aryl sulfide derivative to a molecular skeleton of a light emitting body or a charge transporting body as an organic EL device material, The inventors have found that the above object can be achieved, and have provided the present invention.
[0009]
That is, the present invention is an organic electroluminescent device material comprising a cyclic aryl ether derivative or a cyclic aryl sulfide derivative having a light emitting organic group or a charge transporting organic group.
[0010]
Another aspect of the present invention is an organic electroluminescence device having a light emitting layer or a light emitting layer and a charge transport layer formed between an anode and a cathode, wherein the light emitting layer and / or the charge transport layer is the organic electroluminescent device of the present invention. An organic electroluminescence device comprising a luminescence device material.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, a cyclic aryl ether derivative or a cyclic aryl sulfide derivative having a light-emitting organic group or a charge-transporting organic group used as an organic EL device material includes a light-emitting material and a charge-transporter known as organic EL device materials; Any compound can be used without limitation as long as it is a compound in which a conventionally known cyclic aryl ether derivative or cyclic aryl sulfide derivative is directly and covalently bonded via a divalent organic group or not.
[0012]
In the cyclic aryl ether derivative or the cyclic aryl sulfide derivative used in the present invention, the cyclic aryl ether structure portion or the cyclic aryl sulfide structure portion is a cyclic aryl ether formed by condensation of a dihydroxybenzene and a dihalogenobenzene derivative, such as resorcinol and hydroquinone, Residues derived from known compounds having a heterocalixarene in the skeleton such as thiacalixarene and oxacalixarene can be used without any limitation. For example, J. Konrad Normberski et al. (JCS Perkin Trans 1., p1048, 1977), Bruce C. et al. Gibb et al. (J. Am. Chem. Soc., Vol. 125, p650, 2003), and cyclic aryl ethers and "Calixarenes" (ed. By CD Gutche, Royal Society of Chemistry, 1989). Calixarenes "(edited by J. Vishon et al., Kluer Academic Publishers, 1991), and a review of Boehmer (Angew. Chem. Int. Ed, Engl, 34, p713, 1995). And a residue derivable from the compound.
[0013]
In addition, the light-emitting organic group and the charge-transporting organic group of the cyclic aryl ether derivative or the cyclic arylsulfide derivative used in the present invention include, as a skeleton, a known light-emitting substance or charge-transporting substance used in a conventional organic EL device. Residues can be used without any restrictions. Note that a light-emitting organic group refers to a group that emits fluorescence from an excited singlet or phosphorescence from an excited triplet, and a charge-transporting organic group refers to a group having a hole-transporting ability or an electron-transporting ability. Means However, some luminescent organic groups also exhibit charge transport properties. In that case, there is no particular rule as to which organic group is classified, and furthermore, there is a commonality of structure between these compounds. unacceptable. The charge transporting organic group is further classified into a hole transporting organic group derived from a hole transporter and an electron transporting organic group derived from an electron transporter. These luminescent organic groups and charge transporting organic groups are usually both groups derived from a low molecular weight organic compound or a medium molecular weight organic compound. Those having an average molecular weight of 200 to 4000 are preferable because of easy purification.
[0014]
Preferred examples of the luminescent organic group and the charge transporting organic group in the present invention are as follows.
[0015]
Examples of the luminescent organic group include many styryl derivatives such as distyrylarylene derivatives and styrylamine derivatives; nitrogen-containing aromatic heterocyclic derivatives such as imidazole derivatives; and aromatic rings such as naphthalene derivatives, anthracene derivatives, and perylene derivatives. Condensed hydrocarbon ring derivatives; dyes such as polymethine, xanthone, coumarin, cyanine, and quinacridone; coordination complexes containing beryllium, aluminum, copper, zinc, ruthenium, europium, rhodium, and the like as central metals; Organometallic compounds containing iridium and the like; derivatives in which aromatic groups are polysubstituted such as tetraphenylcyclopentadiene and tetraphenylbutadiene; π-conjugated systems of arylene derivatives such as poly (9,9 dialkylfluorene) derivatives and polyparaphenylene derivatives Medium molecular compound; polythio Π-conjugated middle molecular compound such as an ene derivative; π-conjugated middle molecular compound of an arylene vinylene derivative such as a polyparaphenylene vinylene derivative; pendant middle molecular compound such as a polyvinyl carbazole derivative or a poly (meth) acrylarylamine derivative; Examples include groups derived from a molecular compound in a σ-conjugated system such as polysilane.
[0016]
Among these luminescent organic groups, preferred groups in the present invention include distyrylarylene derivatives, styrylamine derivatives, imidazole derivatives, naphthalene derivatives, anthracene or its derivatives, perylene or its derivatives, and 8-hydroxyquinoline or its derivatives. Examples include groups derived from metal complexes and poly (9,9-dialkylfluorene) derivatives.
[0017]
Next, among the charge transporting organic groups, examples of the hole transporting organic group include groups derived from pyrazoline derivatives, arylamine derivatives, stilbene derivatives, and triphenyldiamine derivatives. Are derived from oxadiazole derivatives, triazole derivatives, anthraquinonedimethane or derivatives thereof, tetracyanoanthraquinodimethane or derivatives thereof, fluorenone derivatives, diphenoquinone derivatives, silole derivatives, and metal complexes of 8-hydroxyquinoline or derivatives thereof. A group can be exemplified.
[0018]
Among these groups, the hole transporting organic groups include arylamine derivatives and triphenyldiamine derivatives, and the electron transporting organic groups include oxadiazole derivatives, silole derivatives, and metal complexes of 8-hydroxyquinoline or derivatives thereof. preferable.
[0019]
In the cyclic aryl ether derivative or the cyclic aryl sulfide derivative used in the present invention, a plurality of light emitting organic groups or charge transporting organic groups may be present in one molecule. In this case, the types of the luminescent organic group and the charge transporting organic group may be the same or different.
[0020]
As these cyclic aryl ether derivatives and cyclic aryl sulfide derivatives that can be suitably used in the present invention from the viewpoint of effects, compounds represented by the following formula (1) can be mentioned.
[0021]
Embedded image

[0022]
Here, Ar in the above formula (1) ¹ And Ar ² Are each independently an aromatic hydrocarbon group, and the aromatic hydrocarbon group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, and specific examples thereof include a phenyl group, a naphthyl group, a tolyl group, Xylyl groups and the like can be mentioned. Further, X in the above formula (1) ¹ And X ² Each independently represents an oxygen atom or a sulfur atom.
[0023]
Also, A in the above formula (1) ¹ And A ² Is independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a group represented by the following formula (2).
[0024]
-(O) _l -(Y) _m -Z (2)
A ¹ Or A ² Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. As the alkyl group, a group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a butyl group is preferable. As the aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and the like are preferable. A group having 6 to 10 carbon atoms is preferable, and as the alkoxy group, a group having 1 to 8 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 2-ethylhexyloxy group is preferably used. it can. The expression (2) will be described later in detail.
[0025]
In the above formula (1), x is an integer of 0 to 10, preferably 0 to 4, y is an integer of 0 to 10, preferably 0 to 4, and x and y are 0 at the same time. And z is an integer of 1 to 20, preferably 1 to 10, and n1 and n2 are each an integer of 0 to 8, preferably 0 to 4. That is, it is preferable that x = 0 to 4, y = 0 to 4, z = 1 to 10, n1 = 0 to 2, and n2 = 0 to 2.
[0026]
Further, in the compound represented by the formula (1), A ¹ And A ² Must be a group represented by the formula (2). Therefore, n1 and n2 do not become 0 at the same time. Furthermore, the same Ar ¹ A ¹ Are bonded to each other, ¹ May be different from each other and have the same Ar ² A ² Are bonded to each other, ² May be different from each other.
[0027]
In the formula (2), O represents an oxygen atom, Y represents a divalent organic group, Z represents a light-emitting organic group or a charge-transporting organic group, and 1 and m each independently represent 0 or Means 1.
[0028]
The divalent organic group represented by Y in the formula (2) is not limited as long as it is a group capable of linking a light-emitting organic group or a charge-transporting organic group to a cyclic aryl ether derivative and a cyclic aryl sulfide derivative. . Preferred examples of the group -Y- include a group represented by the following formula (where R represents an alkyl group and n represents an integer of 0 to 20).
[0029]
Embedded image

[0030]
In addition, as the light-emitting organic group and the charge-transporting organic group represented by Z in the formula (2), a residue having a known light-emitting body or charge-transporter as a skeleton as described above may be used without any limitation. it can. Specific examples of a light-emitting organic group and a charge-transporting organic group suitable for Z are shown below.
[0031]
[I. Luminescent organic group)
(I-1) Singlet-emitting organic group
[0032]
Embedded image

[0033]
Embedded image

[0034]
(In the formula, p and q are each an integer of 1 to 10 and an integer such that the number average molecular weight of each luminescent organic group takes a value in the range of 200 to 4000.)
(I-2) Triplet luminescent organic group
[0035]
Embedded image

[0036]
[II. (Charge transporting organic group)
(II-1) Hole transporting organic group
[0037]
Embedded image

[0038]
Embedded image

[0039]
(II-2) Electron transporting organic group
[0040]
Embedded image

[0041]
Embedded image

[0042]
Embedded image

[0043]
Note that, among the cyclic aryl ether derivatives or cyclic aryl sulfide derivatives represented by the following formula (1), compounds in which the luminescent organic group and the charge transporting organic group are the groups represented by the above (I) and (II), respectively, are novel compounds. is there.
[0044]
Specific examples of the calix derivative suitably used in the present invention are as follows.
[0045]
Embedded image

[0046]
Embedded image

[0047]
Embedded image

[0048]
Embedded image

[0049]
The cyclic aryl ether derivative and the cyclic aryl sulfide derivative used in the present invention have a relatively high glass transition temperature and high thermal stability. The glass transition temperature varies, but is generally around 100 ° C. Therefore, when these cyclic aryl ether derivatives and cyclic aryl sulfide derivatives are used as organic EL device materials, the amount of heat generated when a driving voltage is applied can be suppressed. It is considered that such thermal stability is due to the cyclic aryl ether derivative and the cyclic aryl sulfide derivative having a cyclic structure. Further, the cyclic aryl ether derivative and the cyclic aryl sulfide derivative have no absorption in the visible region. For this reason, the organic EL device material using the cyclic aryl ether derivative and the cyclic aryl sulfide derivative can effectively suppress a decrease in luminous efficiency due to energy transfer or the like.
[0050]
These cyclic aryl ether derivatives and cyclic aryl sulfide derivatives can be used alone as organic EL device materials, but different types can be mixed and used. Further, a cyclic aryl ether derivative or a cyclic aryl sulfide derivative having a light-emitting organic group (collectively referred to as a light-emitting derivative) and a cyclic aryl ether derivative or a cyclic aryl sulfide derivative having a charge transporting organic group (collectively referred to as charge transport ) And can be used as an organic EL device material. In this case, the mixing ratio of the luminescent derivative and the charge transporting derivative is not particularly limited, but generally, the charge transporting derivative is blended in the range of 0.1 to 99.9 parts by weight with respect to 100 parts by weight of the luminescent derivative. Is more preferable, and more preferably in the range of 1 to 99 parts by weight.
[0051]
The method for producing the cyclic aryl ether derivative and the cyclic aryl sulfide derivative used in the present invention is not particularly limited, and can be produced by appropriately combining commonly used synthesis methods. As a preferable synthesis method, a synthesis method shown in the following scheme can be exemplified.
[0052]
In the synthesis of a cyclic aryl ether derivative and a cyclic aryl sulfide derivative, when a cyclic aryl ether structure portion or a cyclic aryl sulfide structure portion is bonded to a light emitting organic group and a charge transporting organic group, the linking group is not used. Examples of useful reactions for directly bonding include, for example, the following reactions (1) to (3).
[0053]
(1) Suzuki Coupling reaction in which an aryl halide or trifuryl aryl is coupled with boronic acid in the presence of Pd (zero valence) and sodium carbonate as a catalyst,
(2) Negishi Coupling reaction in which aryl halide and zinc chloride are coupled in the presence of Pd (zero valence) and Ni (zero valence) catalysts, and
(3) Ullmann Coupling reaction for coupling aryl halides in the presence of a Cu catalyst.
[0054]
In addition, examples of the reaction for bonding via a linking group include the following reactions (1) to (5).
[0055]
(1) a reaction of reacting a carboxylic acid with an amine to form an amide bond,
(2) a reaction between a chloromethyl group and an amine,
(3) Wittig reaction in which phosphorus ylide reacts with a carbonyl group to form a double bond,
(4) a reaction of reacting a phosphate ester with a carbonyl group to form a double bond; and
(5) A reaction in which a Grignard reagent is reacted with a halogen compound to form a carbon-carbon bond.
[0056]
Further, the synthesized cyclic aryl ether derivative and cyclic aryl sulfide derivative are purified by recrystallization or column chromatography. As a solvent used for recrystallization, a known organic solvent or a mixed solvent thereof is used, and preferably, ethanol, isopropyl alcohol, acetone, ethyl acetate, acetonitrile, hexane, heptane, and toluene are used.
[0057]
According to the above production method, the cyclic aryl ether derivative and the cyclic aryl sulfide derivative can be easily purified and isolated. Therefore, the cyclic aryl ether derivative and the cyclic aryl sulfide derivative have a higher utility value as an organic EL device material than a general polymer material having a relatively high impurity concentration and a molecular weight distribution. As described above, the cyclic aryl ether derivative and the cyclic aryl sulfide derivative having a luminescent organic group in the present invention are used as a luminescent material for forming a luminescent layer, and are used as a luminescent material having a charge transporting organic group and a cyclic aryl sulfide derivative. The derivative is extremely useful as a charge transporter for forming a charge transport layer.
[0058]
Regarding the structure of an organic EL device produced using the organic EL device material of the present invention, a light emitting layer containing the organic EL device material of the present invention or a charge transporting material is disposed between a pair of electrodes, at least one of which is transparent or translucent. There is no particular limitation as long as the layer is formed, and a known structure can be employed. For example, a structure having a pair of electrodes, at least one of which is a transparent or translucent electrode, on both surfaces of a light-emitting layer composed of only a light-emitting body or a light-emitting layer composed of a mixture of a light-emitting body and a charge transporter. And those in which a hole transport layer containing a hole transporter is further disposed between the anode and the light emitting layer, and an electron transport layer containing an electron transporter is disposed between the cathode and the light emitting layer.
[0059]
Further, each of the light emitting layer and the charge transport layer may be composed of a plurality of compounds. For example, in a light emitting layer, by mixing one light emitter with another light emitter, energy transfer from one light emitter to another light emitter can be performed, and light can be efficiently emitted from the other light emitter. Other light emitters having such a function are called dopant materials. The compound to be mixed at this time and the number thereof are not particularly limited, and the organic EL device material of the present invention and / or a known luminous body can be used, and the energy relation between a certain luminous body and another luminous body that emits light is optimized. Compounds may be combined as described above. The concentration of the other luminous body is selected in the range of 0.1 to 50% by weight based on the total amount of the luminous body. In the charge transport layer, a plurality of compounds can be mixed for the purpose of balancing the charge injection barrier from the electrode or the charge injection of the device. The number of compounds to be mixed is not particularly limited, and the addition concentration of the other compounds can be in the range of 0.1 to 50% by weight in the total amount as in the case of the above-mentioned luminescent material. Further, a light emitting layer in which a plurality of light emitters and a plurality of charge transporters are mixed can be used.
[0060]
The light emitting layer and the charge transport layer may be a single layer, or a combination of a plurality of layers. Furthermore, a light emitting material other than the organic EL device material of the present invention can be mixed and used in the light emitting layer, and a charge transport material other than the organic EL device material of the present invention can be mixed and used in the charge transporting layer. Further, the light emitting layer and the charge transport layer may be composed of the organic EL device material of the present invention alone, or may be composed of a medium molecular or high molecular compound dispersed therein.
[0061]
Known light-emitting materials (including those that function as dopant materials) that can be used together with the organic EL device material of the present invention are not particularly limited, but compounds represented by the above-described light-emitting organic groups, for example, distyryl arylene Derivatives, styrylamine derivatives, naphthalene derivatives, anthracene or derivatives thereof, perylene or derivatives thereof, polymethine-based, xanthene-based, coumarin-based, cyanine-based pigments, metal complexes of 8-hydroxyquinoline or its derivatives, europium or iridium. Including triplet-emitting metal complexes, aromatic amines, tetraphenylcyclopentadiene or derivatives thereof, or tetraphenylbutadiene or derivatives thereof, poly (9.9 dialkylfluorene) derivatives, polyparaphenylene derivatives, etc. [pi conjugated polymer compound of the polyalkylene derivative, [pi conjugated polymer compounds such as polythiophene derivatives, [pi conjugated polymer compound of the arylene vinylene derivatives such as polyparaphenylene vinylene derivatives, etc. can be used. Specifically, known materials such as those described in JP-A-57-51781 and JP-A-59-194393 can be used.
[0062]
In addition, as examples of known charge transporters that can be used together with the above-described organic EL device material of the present invention, examples of hole transporters include pyrazoline derivatives, arylamine derivatives, stilbene derivatives, and triphenyldiamine derivatives. Examples of the electron transporter include an oxadiazole derivative, anthraquinodimethane or a derivative thereof, a tetracyanoanthraquinodimethane or a derivative thereof, a fluorenone derivative, a diphenoquinone derivative, or a metal complex of 8-hydroxyquinoline or a derivative thereof. Can be.
[0063]
Specific examples of these compounds are described in JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-209988, JP-A-3-37992 and JP-A-3-37992. -152184.
[0064]
Among the above-described charge transporters, the hole transporter is preferably a triphenyldiamine derivative, and the electron transporter is preferably an oxadiazole derivative, or a metal complex of 8-hydroxyquinoline or a derivative thereof. Particularly, as the hole transporter, Is 4,4'-bis (N (3-methylphenyl) -N-phenylamino) biphenyl and 2- (4-t-butylphenyl) -1,3,4-oxadiazole as an electron transporter , Benzoquinone, anthraquinone and tris (8-quinolinol) aluminum are preferred.
[0065]
Among these, one or both of the hole transporter and the electron transporter can be used simultaneously. Each of these materials may be used alone or in combination of two or more. When a charge transport layer is provided between the light emitting layer and the electrode, the charge transport layer may be formed using the above-described charge transporter.
[0066]
When the charge transporter is used in a mixture with the light emitting layer, the amount of the charge transporter varies depending on the type of the compound to be used. And determine it appropriately. Usually, it is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, based on the luminous body.
[0067]
Among these, one or both of the hole transporter and the electron transporter can be used simultaneously. Each of these materials may be used alone or in combination of two or more. When a charge transport layer is provided between the light emitting layer and the electrode, the charge transport layer may be formed using the above-described charge transporter.
[0068]
When the charge transporter is used in a mixture with the light emitting layer, the amount of the charge transporter varies depending on the type of the compound to be used. And determine it appropriately. Usually, it is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, based on the luminous body.
[0069]
Next, a typical method for manufacturing an organic EL device using the organic EL device material of the present invention will be described. First, an anode is formed on a transparent substrate such as glass or transparent plastic using a transparent or translucent metal oxide or metal thin film. As the material, a conductive metal oxide film, a translucent metal thin film, or the like is used. Specifically, a film (NESA or the like) formed using a conductive glass made of indium tin oxide (ITO), tin oxide, or the like, Au, Pt, Ag, Cu, or the like is used. As a manufacturing method, a vacuum evaporation method, a sputtering method, a plating method, or the like is used.
[0070]
Next, a light emitting layer containing the organic EL device material of the present invention is formed on the anode. Examples of the forming method include spin coating, casting, dipping, barcode, roll coating, gravure coating, flexographic printing, spray coating, and inkjet printing using a melt, solution, or mixture of these materials. It is particularly preferable to form a film by a coating method such as a coating method.
[0071]
The thickness of the light emitting layer is preferably from 1 nm to 1 μm, more preferably from 2 to 500 nm. In order to increase the current density and the luminous efficiency, the range of 5 to 200 nm is preferable. In the case of thinning by a coating method, it is preferable to heat and dry under reduced pressure or an inert atmosphere, preferably at a temperature of 30 to 300 ° C, more preferably at a temperature of 60 to 200 ° C, in order to remove the solvent. desirable.
[0072]
When the light emitting layer and the charge transport layer are laminated to improve the charge injection efficiency, the charge transport layer having the hole transport property of the present invention is formed on the anode by the same film forming method as described above. Alternatively, a known hole transporter is formed by a known method, and then a light-emitting layer of the organic EL device material of the present invention is formed by the above-described film forming method, and a charge exhibiting the electron transporting property of the present invention is formed thereon. The transport layer is formed by the same film forming method as described above, or a known electron transporter is formed by a known method.
[0073]
Known film forming methods for the charge transporter are not particularly limited, but include a vacuum deposition method from a powder state, or a spin coating method after being dissolved in a solution, a casting method, a dipping method, a bar code method, a roll coating method, and the like. Can be used.
[0074]
The thickness of the charge transport layer is required to be at least such that pinholes do not occur. However, if the thickness is too large, the resistance of the device increases and a high drive voltage is required, which is not preferable. Therefore, the thickness of the charge transport layer is preferably 1 nm to 1 μm, more preferably 2 nm to 500 nm, and particularly preferably 5 nm to 200 nm.
[0075]
Next, a cathode is provided. This electrode becomes an electron injection cathode. Although the material is not particularly limited, a material having a small ionization energy is preferable. For example, Al, In, Mg, Ca, Li, Mg-Ag alloy, In-Ag alloy, Mg-In alloy, Mg-Al alloy, Mg-Li alloy, Al-Li alloy, Al-Ca alloy, graphite thin film, etc. Is used. As a method for manufacturing the cathode, a vacuum evaporation method, a sputtering method, or the like is used.
[0076]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.
[0077]
Example 1
[0078]
Embedded image

With the compound shown in
[0079]
Embedded image

Was reacted in tetrahydrofuran in the presence of potassium t-butoxide to obtain the desired product (yield 33%). M + 2876 was confirmed by molecular weight analysis (TOF-MS). Table 1 shows the results. Further elemental analysis (Table 11) and ¹ H-nuclear magnetic resonance spectrum ( ¹ H-NMR) was measured to confirm the structure of the compound.
[0080]
Examples 2 to 6
AE-2 to AE-6 were synthesized in the same manner as in Example 1 except that the raw materials shown in Tables 1 to 3 were used. The results are shown in Tables 1 to 3 and Table 14.
[0081]
Example 7
[0082]
Embedded image

With the compound shown in
[0083]
Embedded image

Was reacted with xylene in the presence of palladium acetate, tris (t-butyl) phosphine, and sodium t-butoxy to give the desired product (AE-7) (yield 18%). M by molecular weight analysis (TOF-MASS) ⁺ 2583 were confirmed. Table 4 shows the results. Further elemental analysis (Table 14) and ¹ H-nuclear magnetic resonance spectrum ( ¹ H-NMR) was measured to confirm the structure of the compound.
[0084]
Example 8
An organic EL device material AE-8 was synthesized in the same manner as in Example 7, except that the raw materials shown in Table 4 were used. The results are shown in Tables 4 and 14.
[0085]
Example 9
[0086]
Embedded image

With the compound shown in
[0087]
Embedded image

Was reacted in a mixed solvent of dimethoxyethane / EtOH in the presence of tetrakistriphenylphosphine Pd (0 valence) and sodium carbonate to obtain the desired product (AE-9) (yield: 5%). M was determined by molecular weight analysis (LC-MS). ⁺ 2771 was confirmed. Table 5 shows the results. Further elemental analysis (Table 11) and ¹ H-nuclear magnetic resonance spectrum ( ¹ H-NMR) was measured to confirm the structure of the compound.
[0088]
Example 10
An organic EL device material AE-10 was synthesized in the same manner as in Example 9 except that the raw materials shown in Table 5 were used. The results are shown in Tables 5 and 14.
[0089]
Examples 11 to 15
Organic EL device materials AE-11 to AE-15 were synthesized in the same manner as in Example 7, except that the raw materials shown in Tables 6 to 8 were used. The results are shown in Tables 6 to 8 and Table 14.
[0090]
Examples 16 to 23
Organic EL device materials AE-16 to AE-23 were synthesized in the same manner as in Example 9 except that the raw materials shown in Tables 8 to 12 were used. The results are shown in Tables 8 to 12 and 15.
[0091]
Example 24
The desired product was obtained by reacting the cyclic aryl ether derivative shown in Table 12 with a luminous body in chloroform (yield 12%). The results are shown in Tables 12 and 15.
[0092]
Examples 25 to 26
AE-25 to 26 were synthesized in the same manner as in Example 1 except that the raw materials shown in Table 13 were used. The results are shown in Tables 13 and 15.
[0093]
[Table 1]

[0094]
[Table 2]

[0095]
[Table 3]

[0096]
[Table 4]

[0097]
[Table 5]

[0098]
[Table 6]

[0099]
[Table 7]

[0100]
[Table 8]

[0101]
[Table 9]

[0102]
[Table 10]

[0103]
[Table 11]

[0104]
[Table 12]

[0105]
[Table 13]

[0106]
[Table 14]

[0107]
[Table 15]

[0108]
Example 27 (Film forming characteristics)
The organic EL device material obtained in Example 1 was dissolved in chloroform to prepare a 1% by weight chloroform solution. About 2 g of this solution was applied to a glass surface having a thickness of 2 mm using a spin coater 1H-DX2 manufactured by MIKASA at a rotational speed of 40 r. p. m for 10 seconds → 500r. p. m for 2 seconds → 2000r. p. Spin coating was performed at 45 m for 45 seconds. Further, the spin-coated glass was heated at 80 ° C. to remove the solvent to form a thin film.
When the formed thin film was observed using an optical microscope, no crystals were found. Further, the crystallinity of this thin film was evaluated by an X-ray diffraction method, but no crystal reflection was obtained. From the above, it was found that a thinner version of the compound of Example 1 exhibited amorphous properties and provided good film-forming properties. When the film forming properties of the organic EL materials of Examples 2 to 26 were evaluated in the same manner, thin films showing good amorphous properties were obtained.
[0109]
Example 28 (Fluorescence emission characteristics and EL emission characteristics)
Confirmation of Fluorescence Emission Characteristics: When the AE-1 spin-coated thin film obtained in Example 27 was irradiated with ultraviolet light having a main maximum at 350 nm, blue fluorescence was confirmed. It was measured using a spectrophotometer (Instant Multi-Channel Photo Detector MCPD1000: manufactured by Otsuka Electronics Co., Ltd.), and a spectrum showing an emission maximum at 470 nm was obtained.
[0110]
Evaluation of EL Emission Characteristics: A transparent support substrate was prepared by forming an ITO film with a thickness of 150 nm on a glass substrate of 2.5 mm × 20 mm × 0.8 mm. After etching and washing the transparent support substrate, about 2 g of the above-mentioned 1% by weight chloroform solution of AE-1 was applied to a 2 mm-thick glass surface using a spin coater 1H-DX2 manufactured by MIKASA at a rotational speed of 40 rpm. p. m for 10 seconds → 500r. p. m for 2 seconds → 2000r. p. Spin coating was performed at 45 m for 45 seconds. Further, the film was heated at 80 ° C. under a nitrogen atmosphere to remove the solvent to form a thin film. On top of that, BCP (2,9-dimethyl-4,7-diphenyl-1,10 phenanthroline) was 20 nm as a hole blocking layer, and 50 nm of tris (8-quinolinol) aluminum was used as an electron transporting layer. ) Was deposited at a deposition rate of 0.1 nm / sec. Finally, as a cathode thereon, Ag: Silver = 10: 1 was deposited to a thickness of 100 nm to form an organic EL device. The degree of vacuum at the time of vapor deposition was 1 × 10 ^-5 Torr or less. When a voltage of 12 V was applied to the device and fluorescence emission was measured using a spectrophotometer (MCPD1000, an instantaneous multi-channel photodetector: manufactured by Otsuka Electronics), blue fluorescence having a maximum emission wavelength at 470 nm was observed.
[0111]
Example 29
1% by weight of AE-1 obtained in Example 1 and N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1'-biphenyl] -4,4'-diamine Was dissolved in chlorobenzene at a concentration of 0.5% by weight to prepare a coating solution. A transparent support base was prepared by forming an ITO film with a thickness of 150 nm on a glass substrate of 25 mm × 10 mm × 0.7 mm, and after etching and washing the transparent support base, about 0.4 g of the coating solution prepared above. Was spin-coated on a glass substrate surface at a rotation speed of 1500 rpm for 60 seconds using a spin coater 1H-D7 manufactured by MIKASA. This substrate was heated to 100 ° C. in a nitrogen atmosphere to remove the solvent, thereby forming a thin film. Further, using a vacuum deposition apparatus EBV-6DA manufactured by ULVAC, calcium was deposited as a cathode to a thickness of 40 nm, and then aluminum was deposited to a thickness of 60 nm to prepare an organic EL device. The degree of vacuum during evaporation is 1 × 10 ^-6 Torr or less. When a DC voltage was applied to this element, the light emission luminance was 550 cd / m at 12.5 V. ² Blue emission was obtained. When this light emission was measured using a spectrophotometer (Instant Multi-Channel Photo Detector MCPD1000: manufactured by Otsuka Electronics Co., Ltd.), the maximum light emission wavelength was 470 nm. The results are shown in Table 16.
[0112]
[Table 16]

[0113]
Examples 30 to 44
The EL characteristics were evaluated in the same manner as in Example 29 except that the organic EL materials shown in Table 16 were used. The results are shown in Table 16.
[0114]
Example 45
A mixture of AE-1 and AE-11 (80/20 by weight) was dissolved in xylene at a concentration of 1% by weight to prepare a coating solution. A transparent support base was prepared by forming an ITO film with a thickness of 150 nm on a glass substrate of 25 mm × 10 mm × 0.7 mm, and after etching and washing the transparent support base, about 0.4 g of the coating solution prepared above. Was spin-coated on a glass substrate surface at a rotation speed of 1500 rpm for 60 seconds using a spin coater 1H-D7 manufactured by MIKASA. This substrate was heated to 100 ° C. in a nitrogen atmosphere to remove the solvent, thereby forming a thin film. Further, using a vacuum deposition apparatus EBV-6DA manufactured by ULVAC, calcium was deposited as a cathode to a thickness of 40 nm, and then aluminum was deposited to a thickness of 60 nm to prepare an organic EL device. The degree of vacuum during evaporation is 1 × 10 ^-6 Torr or less. When a DC voltage was applied to this element, the light emission luminance was 1400 cd / m at 12.5 V. ² Blue emission was obtained. When this light emission was measured using a spectrophotometer (Instant Multi-Channel Photo Detector MCPD1000: manufactured by Otsuka Electronics Co., Ltd.), the maximum light emission wavelength was 470 nm. The results are shown in Table 17.
[0115]
Examples 46 to 61
The EL characteristics were evaluated in the same manner as in Example 45, except that each organic EL material was mixed at the composition ratio shown in Table 17. The results are shown in Table 17.
[0116]
[Table 17]

[0117]
Example 62
A mixture (weight ratio 90/10) of AE-1 and ADS129BE (manufactured by American Dysource) as a dopaant was dissolved in xylene at a concentration of 2% by weight to prepare a coating solution.
[0118]
A transparent support base is formed by forming an ITO film on a glass substrate of 25 mm × 10 mm × 0.7 mm with a thickness of 150 nm. After etching and washing the transparent support base, polyethylene dioxythiophene (PEDT) and polystyrene sulfone Baytron P (trade name, manufactured by Bayer AG), which is a 1.56% aqueous solution of an acid (PSS), was spin-coated using a spin coater 1H-D7 manufactured by MIKASA at 1,000 rpm for 60 seconds. This substrate was heated at 200 ° C. for 1 hour using a hot plate. About 0.4 g of the coating solution prepared above was spin-coated on the substrate at 4000 rpm for 30 seconds, and heated to 100 ° C. in a nitrogen atmosphere to remove the solvent, thereby forming a thin film. Further, using a vacuum evaporation apparatus EBV-6DA manufactured by ULVAC, calcium was vapor-deposited as a cathode at 40 nm and then aluminum was vapor-deposited at 80 nm to produce an organic EL device. The degree of vacuum during evaporation is 1 × 10 ^-6 Torr or less. When a DC voltage was applied to this element, the light emission luminance was 2600 cd / m at 12.5 V. ² Blue emission was obtained. This emission was measured using a spectrophotometer (Instant Multi-Channel Photodetector MCPD1000: manufactured by Otsuka Electronics Co., Ltd.), and the maximum emission wavelength was 450 nm. The results are shown in Table 18.
[0119]
[Table 18]

[0120]
Example 63
The same operation as in Example 62 was performed except that ADS128GE (manufactured by American Dysource) was used instead of ADS129BE as the dopant material. The results are shown in Table 18.
[0121]
【The invention's effect】
The organic EL device material of the present invention can be spin-coated and can be easily formed into a film. Further, according to the present invention, an organic EL device material can be easily obtained with high purity. Therefore, the organic EL device material of the present invention is extremely useful as a luminous body and a charge transporter constituting the organic EL device.

Claims (5)

An organic electroluminescent device material comprising a cyclic aryl ether derivative or a cyclic aryl sulfide derivative having a light emitting organic group or a charge transporting organic group. The organic electroluminescent device material according to claim 1, wherein the cyclic aryl ether derivative or the cyclic aryl sulfide derivative having a light emitting organic group or a charge transporting organic group is a compound represented by the following general formula (1).

In the formula, Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group;
X ¹ and X ² are each independently an oxygen atom or a sulfur atom;
A ¹ and A ² are each independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a group represented by the following formula (2);
− (O) ₁ − (Y) _m −Z (2)
(In the formula, O is an oxygen atom, Y is a divalent organic group, Z is a luminescent organic group or a charge transporting organic group, and l and m are each independently 0 or 1.)
x is an integer of 0 to 10, y is an integer of 0 to 10, x and y are not simultaneously 0, z is an integer of 1 to 20,
n1 and n2 are each an integer of 0 to 8, and n1 and n2 do not become 0 at the same time;
At least one of A ¹ and A ² present in the molecule a group represented by the formula (2), if A ¹ in the same Ar ¹ is more binding, A ¹ to the plurality of bond A ² may be different from each other, and when a plurality of A ² are bonded to the same Ar ² , the plurality of A ^{2 to} be bonded may be different from each other. ｝ An organic electroluminescence device comprising a light emitting layer or a light emitting layer and a charge transport layer formed between an anode and a cathode, wherein the light emitting layer and / or the charge transport layer comprises the organic electroluminescent device material according to claim 1 or 2. An organic electroluminescent device, comprising: An organic electroluminescence device according to claim 3, wherein the light emitting layer contains the organic electroluminescence material and the dopant material according to claim 1 or 2. A compound represented by the following formula (1).

[Wherein, Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group;
X ¹ and X ² are each independently an oxygen atom or a sulfur atom;
A ¹ and A ² are each independently a halogen atom, an alkyl group, an aryl group, an alkoxy group or a group represented by the following formula (2);
− (O) ₁ − (Y) _m −Z (2)
Ｏwherein O is an oxygen atom, Y is a divalent organic group, l and m are each independently 0 or 1, and Z is

(In the formula, p and q are integers of 1 to 10 such that the number average molecular weight of each luminescent organic group takes a value in the range of 200 to 4000.)

Or any of the light-emitting organic groups or charge-transporting organic groups. ｝
x is an integer of 0 to 10, y is an integer of 0 to 10, x and y are not simultaneously 0, z is an integer of 1 to 20,
n1 and n2 are each an integer of 0 to 8, and n1 and n2 do not become 0 at the same time;
At least one of A ¹ and A ² present in the molecule a group represented by the formula (2), if A ¹ in the same Ar ¹ is more binding, A ¹ to the plurality of bond A ² may be different from each other, and when a plurality of A ² are bonded to the same Ar ² , the plurality of A ^{2 to} be bonded may be different from each other. ]