JP3760491B2 - Polymer phosphor, method for producing the same, and organic electroluminescence device - Google Patents

Description

【００１８】
（Ｒ₂ 〜Ｒ₃₆は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基及びアルキルチオ基；炭素数６〜１８のアリール基及びアリールオキシ基；並びに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。）
これらのなかでフェニレン基、置換フェニレン基、ビフェニレン基、置換ビフェニレン基、ナフタレンジイル基、置換ナフタレンジイル基、アントラセン−９，１０−ジイル基、置換アントラセン−９，１０−ジイル基、ピリジン−２，５−ジイル基、置換ピリジン−２，５−ジイル基、チエニレン基又は置換チエニレン基が好ましい。
さらに好ましくは、フェニレン基、ビフェニレン基、ナフタレンジイル基、ピリジン−２，５−ジイル基、チエニレン基である。
【００１９】
ここで、置換基について述べると、炭素数１〜２０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、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、ラウリル基などが挙げられ、メチル基、エチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基が好ましい。
また、炭素数１〜２０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、ブトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ヘプチルオキシ基、オクチルオキシ基、デシルオキシ基、ラウリルオキシ基などが挙げられ、メトキシ基、エトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ヘプチルオキシ基、オクチルオキシ基が好ましい。
アルキルチオ基としては、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、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、デシルチオ基、ラウリルチオ基などが挙げられ、メチルチオ基、エチルチオ基、ペンチルチオ基、ヘキシルチオ基、ヘプチルチオ基、オクチルチオ基が好ましい。
アリール基としては、フェニル基、４−Ｃ₁ 〜Ｃ₁₂アルコキシフェニル基（Ｃ₁ 〜Ｃ₁₂は炭素数１〜１２であることを示す。以下も同様である。）、４−Ｃ₁ 〜Ｃ₁₂アルキルフェニル基、１−ナフチル基、２−ナフチル基などが例示される。
アリールオキシ基としては、フェノキシ基が例示される。
複素環化合物基としては２−チエニル基、２−ピロリル基、２−、３−又は４−ピリジル基などが例示される。
【００２０】
本発明の高分子蛍光体において式（１）のＡｒ₂ は、共役結合に関与する炭素原子数が６個以上２２個以下からなる芳香族化合物基又は共役結合に関与するヘテロ原子を含有する炭素数４個以上２０個以下からなる６員環以上の複素環化合物基から選ばれ、これらの基の化学構造式においてＡｒ₂ と隣接する２つの基と結合したＡｒ₂ における２つの炭素原子の間で最短の経路に連続して存在する炭素原子及び窒素原子の個数が１、３又は５のいずれかであるものを示す。
Ａｒ₂ として、化１４に示す２価の芳香族化合物基もしくはその誘導体基、２価の複素環化合物基もしくはその誘導体基又はそれらを組み合わせて得られる基などが例示される。
ここで、例えばＲ₃₇、Ｒ₃₈、Ｒ₃₉、Ｒ₄₀の置換基を有する１番目の基においては、共役結合に関与する炭素原子は、ベンゼン環の６個の炭素原子である。また、Ｒ₄₁、Ｒ₄₂、Ｒ₄₃の置換基を有する２番目の基においては、共役結合に関与する炭素原子は、ヘテロ環の５個の炭素原子である。また、Ｒ₄₈〜Ｒ₅₃の置換基を有する５番目の基においては、ナフタレン環の１０個の炭素原子である。
更に、Ａｒ₂ と隣接する２つの基と結合したＡｒ₂ における２つの炭素原子の間で最短の経路に連続して存在する炭素原子及び窒素原子の個数の合計とは、前記の最初の例では、フェニレン基の１位と３位の炭素原子の間で最短の経路に連続して存在する炭素原子の数は１個であり、２番目の例でも窒素原子を含む基において窒素原子の数は１個となり、５番目の基においては、炭素原子の数は１個となる。
【化１４】

（Ｒ₃₇〜Ｒ₆₉は、それぞれ独立に、水素、シアノ基、炭素数１〜２０のアルキル基、アルコキシ基及びアルキルチオ基；炭素数６〜１８のアリール基及びアリールオキシ基；並びに炭素数４〜１４の複素環化合物基からなる群から選ばれた基である。）
これらのなかでフェニレン基、置換フェニレン基、ビフェニレン基、置換ビフェニレン基、ナフタレンジイル基、置換ナフタレンジイル基、アントラセンジイル基、置換アントラセンジイル基、ピリジンジイル基、置換ピリジンジイル基、が好ましい。
さらに好ましくは、フェニレン基、ビフェニレン基、ナフタレンジイル基、ピリジンジイル基である。
【００２１】
ここで、置換基について述べると、炭素数１〜２０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、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、ラウリル基などが挙げられ、メチル基、エチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基が好ましい。
また、炭素数１〜２０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、ブトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ヘプチルオキシ基、オクチルオキシ基、デシルオキシ基、ラウリルオキシ基などが挙げられ、メトキシ基、エトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ヘプチルオキシ基、オクチルオキシ基が好ましい。
アルキルチオ基としては、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、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、デシルチオ基、ラウリルチオ基などが挙げられ、メチルチオ基、エチルチオ基、ペンチルチオ基、ヘキシルチオ基、ヘプチルチオ基、オクチルチオ基が好ましい。
アリール基としては、フェニル基、４−Ｃ₁ 〜Ｃ₁₂アルコキシフェニル基、４−Ｃ₁ 〜Ｃ₁₂アルキルフェニル基、１−ナフチル基、２−ナフチル基などが例示される。
アリールオキシ基としては、フェノキシ基が例示される。
複素環化合物基としては２−チエニル基、２−ピロリル基、２−、３−又は４−ピリジル基などが例示される。
【００２２】
Ａｒ₃ 、Ａｒ₄ はそれぞれ独立に、共役結合に関与する炭素原子数が４個以上２０個以下からなるアリーレン基又は同じく複素環化合物基であり、化７に示す２価の芳香族化合物基又はその誘導体基、２価の複素環化合物基又はその誘導体基、及びそれらを組み合わせて得られる基などが例示される。
【００２３】
上記式（３）のＲ₁ としては、炭素原子数１〜２２の炭化水素基又は炭素原子数４〜２２の複素環化合物基、Ｘ₁ 及びＸ₂ としてはそれぞれ独立に、−Ｏ−、−Ｓ−、−ＣＯＯ−又は−ＯＣＯ−のいずれかの基であり、ｍ，ｎはそれぞれ０又は１である。溶解性、安定性及び合成の容易さの観点から、式（３）のＸ₁ 及びＸ₂ は、それぞれ独立に−Ｏ−、−ＣＯＯ−又は−ＯＣＯ−が好ましく、−Ｏ−がより好ましい。
【００２４】
また、上記式（３）のＲ₁ において、炭化水素としてはメチレン基、エチレン基、プロピレン基、ブチレン基、ペンチレン基、ヘキシレン基、ヘプチレン基、オクチレン基、デシレン基、ラウリレン基、ビニレン基、フェニレン基、ナフチレン基、アントリレン基などであり、プロピレン基、ブチレン基、ペンチレン基、ヘキシレン基、ヘプチレン基、オクチレン基、デシレン基が好ましい。
複素環化合物基としては、チエニレン基、フラン−２，５−ジイル基、ピリジン−２，３−ジイル基、ピリジン−２，４−ジイル基、ピリジン−２，５−ジイル基、ピリジン−２，６−ジイル基などが例示される。
【００２５】
なお、本発明に用いられる高分子蛍光体は、ランダム、ブロック又はグラフト共重合体であってもよいし、それらの中間的な構造を有する高分子、例えばブロック性を帯びたランダム共重合体であってもよい。蛍光の量子収率の高い共重合体を得る観点からは完全なランダム共重合体よりブロック性を帯びたランダム共重合体やブロック又はグラフト共重合体が好ましい。
本発明の高分子蛍光体の末端の構造は、合成法により異なっており、例えば、アルデヒド基、ハロゲン化メチル基等である。このまま用いてもよいが、これらの末端基と反応して、結合することのできる官能基を有する低分子化合物によって、末端を別の基にしてもよい。末端基と主鎖の結合部分の構造は、特に限定されないが、エチニレン基を介して主鎖と共役結合を形成していることが好ましい。これら末端基の構造としては、ピレニル基、アントリル基、ナフチル基、アルコキシフェニル基、キノリル基、ピリジル基等が例示され、ピレニル基、アントリル基が好ましい。
【００２６】
本発明に用いる高分子蛍光体は、モノマーの組み合わせにより、主鎖に剛直な共役部分と柔軟な連結部分を有する構造とすることができるため、基本的には溶剤に溶解させて成膜することができる。更に溶解性に優れ、成膜性のよい重合体を得るためには、１つの共役部分当たりに、炭素数４〜２０のアルキル基、アルコキシ基もしくはアルキルチオ基；炭素数６〜１８のアリール基もしくはアリールオキシ基；又は炭素数４〜１４の複素環化合物基を置換基として１個以上核置換された芳香族基又は複素環化合物基が少なくとも１つ含まれることが更に好ましい。
【００２７】
これらの置換基としては以下のものが例示される。炭素数４〜２０のアルキル基としては、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、ラウリル基などが挙げられ、ペンチル基、ヘキシル基、ヘプチル基、オクチル基が好ましい。
また、炭素数４〜２０のアルコキシ基としては、ブトキシ基、ペンチルオキシ基、ヘキシルオキシ基、ヘプチルオキシ基、オクチルオキシ基、デシルオキシ基、ラウリルオキシ基などが挙げられ、ペンチルオキシ基、ヘキシルオキシ基、ヘプチルオキシ基、オクチルオキシ基が好ましい。 アルキルチオ基としては、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、デシルチオ基、ラウリルチオ基などが挙げられ、ペンチルチオ基、ヘキシルチオ基、ヘプチルチオ基、オクチルチオ基が好ましい。
アリール基としては、フェニル基、４−Ｃ₁ 〜Ｃ₁₂アルコキシフェニル基、４−Ｃ₁ 〜Ｃ₁₂アルキルフェニル基、１−ナフチル基、２−ナフチル基などが例示される。
アリールオキシ基としては、フェノキシ基が例示される。複素環化合物基としては２−チエニル基、２−ピロリル基、２−、３−又は４−ピリジル基などが例示される。
【００２８】
これら置換基の数は、高分子の分子量と共役鎖長によっても異なるが、溶解性の高い共重合体を得る観点から、これらの置換基が分子量６００当たり１つ以上であることがより好ましい。
【００２９】
なお、本発明の高分子蛍光体に対する良溶媒としては、クロロホルム、塩化メチレン、ジクロロエタン、テトラヒドロフラン、トルエン、キシレンなどが例示される。高分子蛍光体の構造や分子量にもよるが、通常はこれらの溶媒に０．１ｗｔ％以上溶解させることができる。
【００３０】
本発明の高分子蛍光体の重合度は特に限定されず、繰り返し構造やその割合によっても変わる。成膜性の点から一般には繰り返し構造の合計数で好ましくは４〜１００００、さらに好ましくは４〜３０００、特に好ましくは５〜２０００である。
【００３１】
有機ＥＬ素子作成の際に、これらの有機溶媒可溶性の重合体を用いることにより、溶液から成膜する場合、この溶液を塗布後乾燥により溶媒を除去するだけでよく、また後述する電荷輸送材料を混合した場合においても同様な手法が適用でき、製造上非常に有利である。
【００３２】
本発明の高分子蛍光体の製造方法としては、例えば、芳香族ジハロ化合物と芳香族ビスアセチレン化合物とをパラジウム触媒存在下で重合させる方法や芳香族ビス（トリハロゲン化メチル）化合物を還元して重合する方法、特に電気化学的に還元する方法が例示される。しかし、これらの方法は、モノマーの合成方法が複雑であり、また、電解装置を必要とするなど、工業的見地からはあまり有利な方法とは言えない。
【００３３】
本発明の高分子蛍光体の製造方法は、有機溶媒に可溶な高分子であって、該高分子の数平均分子量が１０³ 〜１０⁷ であり、該高分子は上記式（４）、式（５）及び式（６）で表される繰り返し単位から選ばれた少なくとも２つの繰り返し単位を含み、これらの繰り返し単位の和が該高分子の繰り返し単位の５０モル％以上である高分子化合物のビニレン基の炭素−炭素二重結合にハロゲンを付加した後、脱ハロゲン化水素処理することにより、該二重結合をエチニレン結合とするものであり、モノマーの合成が容易であり、また、電解装置も必要としないことから、公知の方法に比べ、工業的に優れた方法であり、特に好ましい。
【００３４】
この場合、ハロゲン化の方法としては、特に限定されないが、芳香環がハロゲンで置換されない条件が好ましい。例えば、冷却下、四塩化炭素のような不活性有機溶媒中で臭素を付加させる方法が例示される。
【００３５】
脱ハロゲン化水素処理の方法としては、特に限定されないが、塩基による脱ハロゲン化水素反応が好ましい。例えば、アルコール溶媒中、水酸化カリウム又はカリウムアルコラートで、脱ハロゲン化水素を行なう方法が例示される。
【００３６】
本発明の有機ＥＬ素子の構造については、少なくとも一方が透明又は半透明である一対の電極間に設ける発光層中に、本発明の高分子蛍光体からなる発光材料が用いられておれば、特に制限はないく、公知の構造が採用される。
例えば、該高分子蛍光体からなる発光層、もしくは該高分子蛍光体と電荷輸送材料（電子輸送材料と正孔輸送材料の総称を意味する）との混合物からなる発光層の両面に一対の電極を有する構造のもの、さらに陰極と発光層の間に、該発光層に隣接して電子輸送材料を含有する電子輸送層、及び／又は陽極と発光層の間に、該発光層に隣接して正孔輸送材料を含む正孔輸送層を積層したものが例示される。
また、発光層や電荷輸送層は１層の場合と複数の層を組み合わせる場合も本発明に含まれる。さらに、発光層に例えば下記に述べる該高分子蛍光体以外の発光材料を混合使用してもよい。また、該高分子蛍光体及び／又は電荷輸送材料を高分子化合物に分散させた層とすることもできる。
【００３７】
本発明の高分子蛍光体とともに使用される電荷輸送材料、すなわち電子輸送材料又は正孔輸送材料としては公知のものが使用でき、特に限定されないが、正孔輸送材料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、ポリ（Ｎ−ビニルカルバゾール）、ポリアニリン及びその誘導体、ポリチオフェン及びその誘導体、ポリ（ｐ−フェニレンビニレン）及びその誘導体、ポリ（２，５−チエニレンビニレン）及びその誘導体等が例示され、電子輸送材料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及びその誘導体、ベンゾキノン及びその誘導体、ナフトキノン及びその誘導体、アントラキノン及びその誘導体、テトラシアノアンスラキノジメタン及びその誘導体、フルオレノン誘導体、ジフェニルジシアノエチレン及びその誘導体、ジフェノキノン誘導体、８−ヒドロキシキノリン及びその誘導体の金属錯体等が例示される。
【００３８】
具体的には、特開昭６３−７０２５７号公報、同６３−１７５８６０号公報、特開平２−１３５３５９号公報、同２−１３５３６１号公報、同２−２０９９８８号公報、同３−３７９９２号公報、同３−１５２１８４号公報に記載されているもの等が例示される。
正孔輸送材料としてはトリフェニルジアミン誘導体、ポリ（Ｎ−ビニルカルバゾール）、電子輸送材料としてはオキサジアゾール誘導体、ベンゾキノン及びその誘導体、アントラキノン及びその誘導体、８−ヒドロキシキノリン及びその誘導体の金属錯体が好ましく、特に、正孔輸送材料としては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、ポリ（Ｎ−ビニルカルバゾール）が好ましく、電子輸送材料としては２−（４−ビフェニリル）−５−（４−ｔ−ブチルフェニル）−１，３，４−オキサジアゾール、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。
これらのうち、電子輸送性の化合物と正孔輸送性の化合物のいずれか一方、又は両方を同時に使用すればよい。これらは単独で用いてもよいし、２種類以上を混合して用いてもよい。
【００３９】
発光層と電極の間に電荷輸送層を設ける場合、これらの電荷輸送材料を使用して電荷輸送層を形成すればよい。
また、電荷輸送材料を発光層に混合して使用する場合、電荷輸送材料の使用量は使用する化合物の種類等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量範囲でそれらを考慮して適宜決めればよい。通常、発光材料に対して１〜４０重量％であり、更に好ましくは２〜３０重量％である。
【００４０】
本発明に用いられる高分子蛍光体と共に使用できる既知の発光材料としては特に限定されないが、例えば、ナフタレン誘導体、アントラセン及びその誘導体、ペリレン及びその誘導体、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及びその誘導体の金属錯体、芳香族アミン、テトラフェニルシクロペンタジエン及びその誘導体、テトラフェニルブタジエン及びその誘導体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号公報、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。
【００４１】
つぎに、本発明の有機ＥＬ素子の代表的な作製方法について述べる。陽極及び陰極からなる一対の電極で、透明又は半透明な電極としては、ガラス、透明プラスチック等の透明基板の上に、透明又は半透明の電極を形成したものが用いられる。
陽極の材料としては、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。
【００４２】
次いで、この陽極上に発光材料として上記高分子蛍光体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液、混合液又は溶融液を使用して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、バーコート法、ロールコート法等の塗布法が例示されるが、溶液又は混合液を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、バーコート法、ロールコート法等の塗布法により成膜するのが特に好ましい。
【００４３】
発光層の厚みとしては好ましくは０．５ｎｍ〜１０μｍ、更に好ましくは１ｎｍ〜１μｍである。電流密度を上げて発光効率を上げるためには１０〜５００ｎｍ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、溶媒を除去するため、減圧下又は不活性雰囲気下、３０〜２００℃、好ましくは６０〜１００℃の温度で加熱乾燥することが望ましい。
【００４４】
また、該発光層と電荷輸送層（正孔輸送層及び電子輸送層の総称を意味する）とを積層する場合には、上記の成膜方法で発光層を設ける前に陽極の上に正孔輸送層を形成すること、及び／又は発光層を設けた後にその上に電子輸送層を形成することが好ましい。
【００４５】
電荷輸送層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、又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、バーコート法、ロールコート法等の塗布法、又は高分子化合物と電荷輸送材料とを溶液状態又は溶融状態で混合し分散させ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、バーコート法、ロールコート法等の塗布法を用いることができる。混合する高分子化合物としては、特に限定されないが、電荷輸送を極度に阻害しないものが好ましく、また、可視光に対する吸収が強くないものが好適に用いられる。
【００４６】
例えば、ポリ（Ｎ−ビニルカルバゾール）、ポリアニリン及びその誘導体、ポリチオフェン及びその誘導体、ポリ（ｐ−フェニレンビニレン）及びその誘導体、ポリ（２，５−チエニレンビニレン）及びその誘導体、ポリカーボネート、ポリアクリレート、ポリメチルアクリレート、ポリメチルメタクリレート、ポリスチレン、ポリ塩化ビニル、ポリシロキサンなどが例示される。成膜が容易に行なえるという点では、塗布法を用いることが好ましい。
【００４７】
電荷輸送層の膜厚は、少なくともピンホールが発生しないような厚みが必要であるが、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、電荷輸送層の膜厚は好ましくは０．５ｎｍ〜１０μｍ、更に好ましくは１ｎｍ〜１μｍ、特に好ましくは５〜２００ｎｍである。
【００４８】
次いで、発光層又は電子輸送層の上に電極を設ける。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、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。
【００４９】
【実施例】
以下本発明の実施例を示すが、本発明はこれらに限定されるものではない。
実施例１
＜素子構造＞
本発明の有機ＥＬ素子の一実施例を示す。ガラス基板上に、ＩＴＯ透明電極、正孔輸送層、高分子発光層、電子輸送層、背面電極が積層されたもので構成されている。
＜高分子蛍光体１の合成＞
２，５−ジオクチルオキシ−ｐ−キシリレンジクロライドをＮ，Ｎ−ジメチルホルムアミド中、トリフェニルホスフィンと反応させてホスホニウム塩を合成した。得られたホスホニウム塩９．５５ｇ、イソフタルアルデヒド０．６７ｇ、及びテレフタルアルデヒド０．６７ｇを、エチルアルコールに溶解させた。１．５６ｇのリチウムエトキシドを含むエチルアルコール溶液をホスホニウム塩とジアルデヒドのエチルアルコール溶液に滴下し、室温で３時間重合させた。一夜室温で放置した後、沈澱を濾別し、エチルアルコールで洗浄後、クロロホルムに溶解した。この溶液にエタノールを加え、再沈精製した。これを減圧乾燥して、重合体を得た。
【００５０】
この重合体３．０ｇを四塩化炭素１２０ｇに溶解した。この溶液に、臭素３．１ｇを四塩化炭素２０ｇに溶解した液を滴下、引続き室温で２時間撹拌し、重合体の臭素化を行った。この溶液を室温で濃縮した後、これにエタノールを加え、生成した沈澱を回収し、これをエタノールで洗浄した後、減圧乾燥して、臭素化された重合体５ｇを得た。
次に、脱ハロゲン化水素反応を行った。第三ブタノール７０ｇに、第三ブトキシカリウム３．１４ｇを溶解し、７０℃まで昇温した液に、臭素化した重合体２．７３ｇをキシレン７０ｇに溶解した液を滴下した。引き続いて、９０℃で７時間反応した。この溶液を冷却した後、多量のメタノール中にそそぎ込み、生成した沈澱を回収した。この沈澱をエタノールで洗浄した。つぎに、この沈澱をクロロホルムに溶解した。この溶液にエタノールを加え、再沈精製した。これを減圧乾燥して、エチニレン基を有する重合体０．５ｇを得た。これを高分子蛍光体１という。
【００５１】
該高分子蛍光体１のポリスチレン換算の数平均分子量は、７．０×１０⁴ であった。ここで、数平均分子量については、クロロホルムを溶媒として、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によりポリスチレン換算の数平均分子量を求めた。該高分子蛍光体１の構造については赤外吸収スペクトル、ＮＭＲで確認した。
【００５２】
＜蛍光強度の測定＞
高分子蛍光体１を、クロロホルムに溶解した。その０．４％クロロホルム溶液を石英板上にスピンコートして重合体の薄膜を得た。この薄膜の蛍光スペクトルを日立製作所製蛍光分光光度計８５０を用いて測定した。蛍光の量子収率の算出には、４１０ｎｍで励起したときの蛍光スペクトルを用いた。蛍光強度は、横軸に波数をとってプロットした蛍光スペクトルの面積を、４１０ｎｍでの吸光度で割ることにより相対値として求めた。得られた高分子蛍光体１の螢光強度（相対値）を表１に示す。
【００５３】
＜素子の作成及び評価＞
スパッタリングによって、４０ｎｍの厚みでＩＴＯ膜を付けたガラス基板に、実施例１で合成した高分子蛍光体１の１．０ｗｔ％クロロホルム溶液を用いて、スピンコーティングにより５０ｎｍの厚みで成膜した。次いで、これを減圧下８０℃で１時間乾燥した後、その上に陰極としてアルミニウム−リチウム合金（Ａｌ：Ｌｉ＝１００：１重量比）を１５０ｎｍ蒸着して有機ＥＬ素子を作製した。蒸着のときの真空度はすべて８×１０^-6Ｔｏｒｒ以下であった。
この素子に電圧を印加したところ青緑色の発光が認められる。
【００５４】
実施例２
＜高分子蛍光体２の合成＞
２，５−ジオクチルオキシ−ｐ−キシリレンジクロライドをＮ，Ｎ−ジメチルホルムアミド中、トリフェニルホスフィンと反応させてホスホニウム塩を合成した。得られたホスホニウム塩１２ｇと、ｐ−ヒドロキシベンズアルデヒドをエチルアルコール溶媒中水酸化カリウムと反応させ、カリウムフェノラートとした後、これに１，６ージブロムーｎーヘキサンを反応させて得られた、ジアルデヒド化合物２．０５ｇとイソフタルアルデヒド０．８５ｇとを、エチルアルコール／クロロホルム混合溶媒に溶解させた。１．５６ｇのリチウムエトキシドを含むエチルアルコール溶液をホスホニウム塩とジアルデヒドのエチルアルコール／クロロホルム溶液に滴下し、室温で３時間重合させた。一夜室温で放置した後、沈澱を濾別し、エチルアルコールで洗浄後、クロロホルムに溶解した。この溶液にエタノールを加え、再沈精製した。これを減圧乾燥して、重合体を得た。
この重合体５．０ｇを四塩化炭素１２０ｇに溶解した。この溶液に、臭素４．２ｇを四塩化炭素２０ｇに溶解した液を滴下、引続き室温で２時間撹拌し、重合体の臭素化を行った。この溶液を室温で濃縮した後、これにエタノールを加え、生成した沈澱を回収し、エタノールで洗浄した後、減圧乾燥して、臭素化された重合体８．９ｇを得た。
【００５５】
次に、脱ハロゲン化水素反応を行った。第三ブタノール７０ｇに、第三ブトキシカリウム４．４８ｇを溶解し、７０℃まで昇温した液に、臭素化した重合体４．４６ｇをキシレン８０ｇに溶解した液を滴下した。引き続いて、９０℃で７時間反応した。この溶液を冷却した後、多量のメタノール中にそそぎ込み、生成した沈澱を回収した。この沈澱をエタノールで洗浄した。つぎに、この沈澱をクロロホルムに溶解した。この溶液にエタノールを加え、再沈精製した。これを減圧乾燥して、エチニレン基を有する重合体０．９ｇを得た。これを高分子蛍光体２という。
該高分子蛍光体２のポリスチレン換算の数平均分子量は、２．０×１０⁴ であった。ここで、数平均分子量については、クロロホルムを溶媒として、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によりポリスチレン換算の数平均分子量を求めた。該高分子蛍光体２の構造については赤外吸収スペクトル、ＮＭＲで確認した。
【００５６】
＜蛍光強度の測定＞
実施例１と同様にして測定して得られた該高分子蛍光体２の螢光強度（相対値）を表１に示す。
【００５７】
＜素子の作成及び評価＞
スパッタリングによって、４０ｎｍの厚みでＩＴＯ膜を付けたガラス基板に、実施例２で合成した高分子蛍光体２の１．０ｗｔ％クロロホルム溶液を用いて、スピンコーティングにより５０ｎｍの厚みで成膜した。次いで、これを減圧下８０℃で１時間乾燥した後、その上に陰極としてアルミニウム−リチウム合金（Ａｌ：Ｌｉ＝１００：１重量比）を１５０ｎｍ蒸着して有機ＥＬ素子を作製した。蒸着のときの真空度はすべて８×１０^-6Ｔｏｒｒ以下であった。
この素子に電圧を印加したところ青色の発光が認められる。
【００５８】
比較例１
＜高分子蛍光体３の合成＞
第三ブチルアルコール７０ｇに第三ブトキシカリウム６．７ｇを溶解した液をおよそ７０℃まで昇温、この液に、２，５−ジオクチルオキシ−ｐ−キシリレンジクロライド８．６ｇをキシレン８０ｇに溶解した液を滴下した後、約９０℃で７時間反応した。この溶液を冷却した後、大量のメタノール中にそそぎ込んだところ、赤色の沈澱が生成した。この沈澱を回収した後、メタノールで洗浄、続いてエタノール／水混合溶媒で洗浄、さらにエタノールで洗浄した。つぎに、この沈澱をクロロホルムに溶解した。この溶液にエタノールを加え、再沈精製した。これを減圧乾燥して、ポリ（２，５−ジオクチルオキシ−ｐ−フェニレンビニレン）を得た。
この重合体１．０７ｇを四塩化炭素５０ｇに溶解した。この溶液に、臭素１ｇを四塩化炭素１０ｇに溶解した液を滴下、引続き室温で２時間撹拌し、重合体の臭素化を行った。この溶液にエタノールを加え、生成した沈澱を回収し、エタノールで洗浄した後、減圧乾燥して、臭素化された重合体を得た。
次に、脱ハロゲン化水素反応を行った。第三ブタノールに、第三ブトキシカリウムを溶解し、７０℃まで昇温した液に、臭素化した重合体１．０２ｇをキシレン３０ｇに溶解した液を滴下した。引き続いて、９０℃で７時間反応した。この溶液を冷却した後、多量のメタノール中にそそぎ込み、生成した沈澱を回収した。この沈澱をエタノールで洗浄した後、減圧乾燥して、エチニレン基を有する重合体０．２ｇを得た。これを高分子蛍光体３という。
【００５９】
該高分子蛍光体３のポリスチレン換算の数平均分子量は、１．８×１０⁴ であった。ここで、数平均分子量については、クロロホルムを溶媒として、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によりポリスチレン換算の数平均分子量を求めた。該高分子蛍光体３の構造については赤外吸収スペクトル、ＮＭＲで確認した。
【００６０】
＜蛍光強度の測定＞
実施例１と同様にして測定して得られた該高分子蛍光体３の螢光強度（相対値）を表１に示す。
高分子蛍光体１及び２の蛍光強度は、表１に示すとおり強かった。
【表１】

【００６１】
【発明の効果】
本発明の高分子蛍光体は、高い蛍光の量子収率を有している上、溶媒に可溶であり、有機ＥＬ素子の発光材料、色素レーザー用の色素等として好適に用いることができる。また、塗布法により、容易に発光層を形成することができることから、有機ＥＬ素子を容易に作成することができる。
さらに、本発明の高分子発光体を用いた有機ＥＬ素子は、熱的にも安定な高分子蛍光体を用いているので、バックライトとしての面状光源，フラットパネルディスプレイ等の装置として好ましく使用できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polymer phosphor for an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element), a production method thereof, and an organic electroluminescence element produced using the same. More specifically, the present invention relates to a polymer fluorescent substance having strong solvent-soluble fluorescence, a method for producing the same, and an organic electroluminescence device produced using the same.
[0002]
[Prior art]
An inorganic electroluminescence element (hereinafter, sometimes referred to as an inorganic EL element) using an inorganic phosphor as a light emitting material is used for display devices such as a planar light source or a flat panel display as a backlight. High voltage alternating current was necessary to make it.
In recent years, Tang et al. Fabricated an organic EL device having a two-layer structure in which an organic fluorescent dye is used as a light emitting layer and an organic charge transport compound used in an electrophotographic photoreceptor or the like is laminated. A high-efficiency, high-brightness organic EL element was realized (Japanese Patent Laid-Open No. 59-194393). Compared to inorganic EL elements, organic EL elements have the characteristics that light emission of a large number of colors can be easily obtained in addition to low voltage drive and high luminance, so there are many element structures, organic fluorescent dyes, and organic charge transport compounds. An attempt has been reported [Japanese Journal of Applied Physics (Jpn. J. Appl. Phys.), Vol. 27, L269 (1988)], [Journal of Applied Physics (J. Appl. Phys.) 65, 3610 (1989)].
[0003]
Moreover, as a high molecular weight light emitting material, WO90113148 publication specification, Unexamined-Japanese-Patent No. 3-244630, Applied Physics Letters (Appl. Phys. Lett.) 58th volume, 1982 (1991) ) Etc. In an example of the specification of WO90113148, a poly-p-phenylene vinylene thin film converted into a conjugated polymer was obtained by forming a soluble precursor on an electrode and performing a heat treatment, and the resultant was used. An EL element is disclosed.
Japanese Patent Application Laid-Open No. 3-244630 exemplifies a conjugated polymer that is itself soluble in a solvent and does not require heat treatment. Applied Physics Letters (Appl. Phys. Lett.), 58, 1982 (1991) also describes a polymer light-emitting material soluble in a solvent and an organic EL device produced using the same.
Furthermore, US Pat. No. 5,352,906 discloses poly (p-phenyleneacetylene), which is characterized by being thermally stable.
In addition, as a method for producing poly (p-phenylacetylene), an aromatic diacetylene compound and an aromatic dihalogen compound are disclosed in The Chemical Society of Japan, Vol. 57, page 752 (1984). A method of polymerizing in the presence of a catalyst is disclosed. In US Pat. No. 5,352,906, the polymer is obtained in the same manner. Chemistry Letters, page 1727 (1987) discloses a process for producing the polymer by electrolytic polymerization.
[0004]
However, the polymeric fluorescent substances reported so far cannot be said to have a sufficient quantum yield of fluorescence, and cannot be said to be sufficiently soluble in a solvent, or because only the intermediate is soluble. It was not always easy to reduce the thickness of the EL element for use as a light emitting layer. There has been a demand for an organic EL element that can be easily produced by a coating method using a polymeric fluorescent substance that has a high fluorescence quantum yield and is sufficiently soluble in a solvent.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a polymer fluorescent substance having a high fluorescence quantum yield and soluble in a solvent, a method for producing the same, and a light emitting layer that can be easily formed by a coating method using the polymer phosphor. It is to provide an organic electroluminescence device having the same.
[0006]
[Means for Solving the Problems]
In view of such circumstances, the present inventors have made a polymer phosphor that is soluble in a solvent and has a high fluorescence yield in order to easily produce an organic EL device using the polymer phosphor as a light emitting layer. Have been studying earnestly. As a result, it was found that a polymer fluorescent substance having a repeating unit having an ethynylene bond as a main chain and having a specific structure as a polymer light emitter exhibits a high quantum yield of fluorescence. It was.
[0007]
That is, the present invention [1] is a polymer soluble in an organic solvent, and the polymer has a number average molecular weight of 10 ^Three -10 ⁷ The polymer contains at least two repeating units selected from repeating units represented by the following formula (1), formula (2) and formula (3), and the sum of these repeating units is the polymer. The polymeric fluorescent substance is characterized in that it is 50 mol% or more of the repeating unit.
[Chemical 7]
-Ar ₁ -C≡C- (1)
[Chemical 8]
-Ar ₂ -C≡C- (2)
[Chemical 9]
-Ar _Three -(X ₁ ) _m -R ₁ -(X ₂ ) _n -Ar _Four -C≡C- (3)
(Wherein Ar ₁ Is an aromatic compound group having 6 or more and 22 or less carbon atoms involved in a conjugated bond, or a 5-membered ring or more consisting of 4 or more and 20 or less carbon atoms containing a hetero atom involved in a conjugated bond. Selected from the group of heterocyclic compounds, Ar in the chemical structural formula of these groups ₁ Ar bonded to two adjacent groups ₁ In which the sum of the number of carbon atoms and nitrogen atoms present continuously in the shortest path between two carbon atoms is an even number.
[0008]
Ar ₂ Is an aromatic compound group having 6 to 22 carbon atoms involved in a conjugated bond or a heterocycle having 6 to 20 carbon atoms having a hetero atom participating in a conjugated bond and having 4 to 20 carbon atoms. Selected from ring compound groups, Ar in the chemical structure of these groups ₂ Ar bonded to two adjacent groups ₂ In which the number of carbon atoms and nitrogen atoms present continuously in the shortest path between two carbon atoms is any one of 1, 3 and 5.
Ar _Three , Ar _Four Are each independently a group selected from the group consisting of an aromatic group having 4 to 20 carbon atoms involved in a conjugated bond or a heterocyclic compound group.
R ₁ Is a hydrocarbon group having 1 to 22 carbon atoms or a heterocyclic compound group having 4 to 22 carbon atoms, ₁ , X ₂ Each independently represents —O—, —S—, —COO— or —OCO—, and m and n are each independently 0 or 1. )
[0009]
The present invention also provides [2] a polymer soluble in an organic solvent, wherein the polymer has a number average molecular weight of 10 ^Three -10 ⁷ The polymer contains at least two repeating units selected from repeating units represented by the following formula (4), formula (5) and formula (6), and the sum of these repeating units is the polymer. After adding a halogen to the carbon-carbon double bond of the vinylene group of the polymer compound that is 50 mol% or more of the repeating unit, the dehydrogenation treatment is performed to convert the double bond into an ethynylene bond. The present invention relates to a method for producing a polymeric fluorescent substance according to [1].
[Chemical Formula 10]
-Ar ₁ -CH = CH- (4)
Embedded image
-Ar ₂ -CH = CH- (5)
Embedded image
-Ar _Three -(X ₁ ) _m -R ₁ -(X ₂ ) _n -Ar _Four -C = C- (6)
(Wherein Ar ₁ , Ar ₂ , Ar _Three , Ar _Four , R ₁ , X ₁ , X ₂ , M, and n are the same as defined in [1]. )
[0010]
Furthermore, the present invention provides [3] an organic electroluminescence device having at least a light emitting layer between electrodes composed of a pair of an anode and a cathode, at least one of which is transparent or translucent. The present invention relates to an organic electroluminescence device comprising a molecular phosphor.
[0011]
Further, the present invention provides [4] the organic electroluminescence device according to [3], further comprising a layer containing an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer. The present invention relates to a characteristic organic electroluminescence element.
[0012]
Further, the present invention provides [5] the organic electroluminescent element according to the above [3], further comprising a layer containing a hole transporting compound adjacent to the light emitting layer between the anode and the light emitting layer. The present invention relates to an organic electroluminescence device characterized by the following.
[0013]
Further, the present invention provides [6] the organic electroluminescent device according to the above [3], a layer containing an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer, an anode and a light emitting device. The present invention relates to an organic electroluminescence device characterized in that a layer containing a hole transporting compound is provided adjacent to the light emitting layer.
Hereinafter, the organic EL device of the present invention will be described in detail.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The polymeric fluorescent substance of the present invention contains at least two repeating units selected from repeating units represented by formula (1), formula (2) and formula (3), and the sum of these repeating units is It is 50 mol% or more of the repeating unit of the polymer. The remaining repeating units may include, for example, at least two repeating units selected from the repeating units represented by Formula (4), Formula (5), and Formula (6).
[0015]
The conjugated chain length of the polymeric fluorescent substance of the present invention is preferably longer from the viewpoint of charge transfer, while the conjugated chain length is better from the viewpoint of obtaining a polymeric fluorescent substance having a high fluorescence quantum yield. By appropriately selecting the amount of the repeating unit represented by the formula (2) and / or the formula (3) and the repeating unit represented by the formula (1) in the polymeric fluorescent substance, the conjugated chain length has an appropriate size. Can be.
[0016]
Ar of formula (1) in the polymeric fluorescent substance of the present invention ₁ Is an aromatic compound group having 6 or more and 22 or less carbon atoms involved in a conjugated bond, or a 5-membered ring or more consisting of 4 or more and 20 or less carbon atoms containing a hetero atom involved in a conjugated bond. Selected from the group of heterocyclic compounds, Ar in the chemical structural formula of these groups ₁ Ar bonded to two adjacent groups ₁ In which the sum of the number of carbon atoms and nitrogen atoms present continuously in the shortest path between two carbon atoms is an even number. Here, being involved in a conjugated bond means that it is involved in the formation of a conjugated bond, that is, a conjugated bond is formed.
Specifically, Ar ₁ Examples thereof include a divalent aromatic compound group shown in Chemical formula 13 or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, or a group obtained by combining them. Here, for example, R ₂ , R _Three , R _Four , R _Five In the first group having the substituent, the carbon atoms involved in the conjugated bond are the six carbon atoms of the benzene ring. R ₆ , R ₇ , R ₈ In the second group having the substituent, the carbon atoms involved in the conjugated bond are the five carbon atoms of the heterocyclic ring. R ₁₃ ~ R ₁₈ In the fifth group having the following substituents, it is 10 carbon atoms of the naphthalene ring.
Furthermore, Ar ₁ Ar bonded to two adjacent groups ₁ In the above first example, the total number of carbon atoms and nitrogen atoms present in succession in the shortest path between two carbon atoms in the above is between the 1st and 4th carbon atoms of the phenylene group. The number of carbon atoms continuously present in the shortest path is two, and in the second example, the number is 2 in the group containing a nitrogen atom, and in the fifth group is 4.
[0017]
Embedded image

[0018]
(R ₂ ~ R ₃₆ Are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; aryl group and aryloxy group having 6 to 18 carbon atoms; and heterocyclic compound group having 4 to 14 carbon atoms A group selected from the group consisting of )
Among these, phenylene group, substituted phenylene group, biphenylene group, substituted biphenylene group, naphthalenediyl group, substituted naphthalenediyl group, anthracene-9,10-diyl group, substituted anthracene-9,10-diyl group, pyridine-2, A 5-diyl group, a substituted pyridine-2,5-diyl group, a thienylene group or a substituted thienylene group is preferred.
More preferred are a phenylene group, a biphenylene group, a naphthalenediyl group, a pyridine-2,5-diyl group, and a thienylene group.
[0019]
Here, the substituent is described. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group. A methyl group, an ethyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group, and lauryloxy group. A methoxy group, an ethoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group are preferable.
Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, and a laurylthio group. , A heptylthio group and an octylthio group are preferable.
As the aryl group, a phenyl group, 4-C ₁ ~ C ₁₂ Alkoxyphenyl group (C ₁ ~ C ₁₂ Indicates that the number of carbon atoms is 1 to 12. The same applies to the following. ), 4-C ₁ ~ C ₁₂ Examples thereof include an alkylphenyl group, a 1-naphthyl group, and a 2-naphthyl group.
A phenoxy group is illustrated as an aryloxy group.
Examples of the heterocyclic compound group include 2-thienyl group, 2-pyrrolyl group, 2-, 3- or 4-pyridyl group.
[0020]
Ar of formula (1) in the polymeric fluorescent substance of the present invention ₂ Is an aromatic compound group having 6 to 22 carbon atoms involved in a conjugated bond or a heterocycle having 6 to 20 carbon atoms having a hetero atom participating in a conjugated bond and having 4 to 20 carbon atoms. Selected from ring compound groups, Ar in the chemical structure of these groups ₂ Ar bonded to two adjacent groups ₂ In which the number of carbon atoms and nitrogen atoms present continuously in the shortest path between two carbon atoms is any one of 1, 3 and 5.
Ar ₂ Examples thereof include a divalent aromatic compound group represented by Chemical formula 14 or a derivative group thereof, a divalent heterocyclic compound group or a derivative group thereof, or a group obtained by combining them.
Here, for example, R ₃₇ , R ₃₈ , R ₃₉ , R ₄₀ In the first group having the substituent, the carbon atoms involved in the conjugated bond are the six carbon atoms of the benzene ring. R ₄₁ , R ₄₂ , R ₄₃ In the second group having the substituent, the carbon atoms involved in the conjugated bond are the five carbon atoms of the heterocyclic ring. R ₄₈ ~ R ₅₃ In the fifth group having the following substituents, it is 10 carbon atoms of the naphthalene ring.
Furthermore, Ar ₂ Ar bonded to two adjacent groups ₂ In the above first example, the total number of carbon atoms and nitrogen atoms present in succession in the shortest path between two carbon atoms in the group between the 1st and 3rd carbon atoms of the phenylene group The number of carbon atoms continuously present in the shortest path is one, and even in the second example, the number of nitrogen atoms is one in the group containing a nitrogen atom, and in the fifth group, the number of carbon atoms is Is one.
Embedded image

(R ₃₇ ~ R ₆₉ Are each independently hydrogen, cyano group, alkyl group having 1 to 20 carbon atoms, alkoxy group and alkylthio group; aryl group and aryloxy group having 6 to 18 carbon atoms; and heterocyclic compound group having 4 to 14 carbon atoms A group selected from the group consisting of )
Among these, a phenylene group, a substituted phenylene group, a biphenylene group, a substituted biphenylene group, a naphthalenediyl group, a substituted naphthalenediyl group, an anthracenediyl group, a substituted anthracenediyl group, a pyridinediyl group, and a substituted pyridinediyl group are preferable.
More preferred are a phenylene group, a biphenylene group, a naphthalenediyl group, and a pyridinediyl group.
[0021]
Here, the substituent is described. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group. A methyl group, an ethyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group, and lauryloxy group. A methoxy group, an ethoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group are preferable.
Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, and a laurylthio group. , A heptylthio group and an octylthio group are preferable.
As the aryl group, a phenyl group, 4-C ₁ ~ C ₁₂ Alkoxyphenyl group, 4-C ₁ ~ C ₁₂ Examples thereof include an alkylphenyl group, a 1-naphthyl group, and a 2-naphthyl group.
A phenoxy group is illustrated as an aryloxy group.
Examples of the heterocyclic compound group include 2-thienyl group, 2-pyrrolyl group, 2-, 3- or 4-pyridyl group.
[0022]
Ar _Three , Ar _Four Are each independently an arylene group having 4 to 20 carbon atoms involved in a conjugated bond or a heterocyclic compound group, and a divalent aromatic compound group represented by Chemical Formula 7 or a derivative group thereof; Examples thereof include a valent heterocyclic compound group or a derivative group thereof, and a group obtained by combining them.
[0023]
R in the above formula (3) ₁ As a hydrocarbon group having 1 to 22 carbon atoms or a heterocyclic compound group having 4 to 22 carbon atoms, X ₁ And X ₂ Each independently represents —O—, —S—, —COO— or —OCO—, and m and n are each 0 or 1. From the viewpoint of solubility, stability, and ease of synthesis, X in formula (3) ₁ And X ₂ Are each independently preferably —O—, —COO— or —OCO—, more preferably —O—.
[0024]
In addition, R in the above formula (3) ₁ The hydrocarbons include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, decylene, laurylene, vinylene, phenylene, naphthylene, anthrylene, and the like. , Propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group and decylene group are preferable.
As the heterocyclic compound group, thienylene group, furan-2,5-diyl group, pyridine-2,3-diyl group, pyridine-2,4-diyl group, pyridine-2,5-diyl group, pyridine-2, Examples include 6-diyl group.
[0025]
The polymeric fluorescent substance used in the present invention may be a random, block or graft copolymer, or a polymer having an intermediate structure thereof, such as a random copolymer having a block property. There may be. From the viewpoint of obtaining a copolymer having a high fluorescence quantum yield, a random copolymer having a block property and a block or graft copolymer are preferable to a complete random copolymer.
The terminal structure of the polymeric fluorescent substance of the present invention varies depending on the synthesis method, and examples thereof include an aldehyde group and a methyl halide group. Although it may be used as it is, the terminal may be changed to another group by a low molecular weight compound having a functional group capable of reacting with and binding to these terminal groups. The structure of the binding portion between the terminal group and the main chain is not particularly limited, but it is preferable that a conjugated bond is formed with the main chain via an ethynylene group. Examples of the structure of these terminal groups include a pyrenyl group, anthryl group, naphthyl group, alkoxyphenyl group, quinolyl group, pyridyl group, and the like, and a pyrenyl group and an anthryl group are preferable.
[0026]
The polymeric fluorescent substance used in the present invention can have a structure having a rigid conjugated part and a flexible linking part in the main chain by a combination of monomers. Therefore, the polymeric fluorescent substance is basically formed by dissolving in a solvent. Can do. Further, in order to obtain a polymer having excellent solubility and good film forming property, an alkyl group having 4 to 20 carbon atoms, an alkoxy group or an alkylthio group; an aryl group having 6 to 18 carbon atoms or It is more preferable that at least one aromatic group or heterocyclic compound group that is substituted with one or more nucleus by using an aryloxy group; or a heterocyclic compound group having 4 to 14 carbon atoms as a substituent.
[0027]
Examples of these substituents are as follows. Examples of the alkyl group having 4 to 20 carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, and a lauryl group, and a pentyl group, a hexyl group, a heptyl group, and an octyl group are preferable.
Examples of the alkoxy group having 4 to 20 carbon atoms include a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, a lauryloxy group, and the like, such as a pentyloxy group and a hexyloxy group. , A heptyloxy group and an octyloxy group are preferable. Examples of the alkylthio group include a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group, a decylthio group, and a laurylthio group, and a pentylthio group, a hexylthio group, a heptylthio group, and an octylthio group are preferable.
As the aryl group, a phenyl group, 4-C ₁ ~ C ₁₂ Alkoxyphenyl group, 4-C ₁ ~ C ₁₂ Examples thereof include an alkylphenyl group, a 1-naphthyl group, and a 2-naphthyl group.
A phenoxy group is illustrated as an aryloxy group. Examples of the heterocyclic compound group include 2-thienyl group, 2-pyrrolyl group, 2-, 3- or 4-pyridyl group.
[0028]
The number of these substituents varies depending on the molecular weight of the polymer and the conjugated chain length, but from the viewpoint of obtaining a highly soluble copolymer, the number of these substituents is more preferably 1 or more per 600 molecular weight.
[0029]
Examples of the good solvent for the polymeric fluorescent substance of the present invention include chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene and the like. Although depending on the structure and molecular weight of the polymeric fluorescent substance, it can usually be dissolved in these solvents in an amount of 0.1 wt% or more.
[0030]
The degree of polymerization of the polymeric fluorescent substance of the present invention is not particularly limited, and varies depending on the repeating structure and the ratio thereof. In general, the total number of repeating structures is preferably 4 to 10000, more preferably 4 to 3000, and particularly preferably 5 to 2000 in terms of film formability.
[0031]
When forming a film from a solution by using these organic solvent-soluble polymers at the time of preparing an organic EL device, it is only necessary to remove the solvent by drying after applying this solution. Even in the case of mixing, the same technique can be applied, which is very advantageous in production.
[0032]
As a method for producing the polymeric fluorescent substance of the present invention, for example, a method in which an aromatic dihalo compound and an aromatic bisacetylene compound are polymerized in the presence of a palladium catalyst or an aromatic bis (trihalogenated methyl) compound is reduced. A method for polymerization, particularly a method for electrochemical reduction is exemplified. However, these methods are not very advantageous from an industrial standpoint because the method for synthesizing monomers is complicated and an electrolysis apparatus is required.
[0033]
The method for producing a polymeric fluorescent substance according to the present invention is a polymer soluble in an organic solvent, and the polymer has a number average molecular weight of 10 ^Three -10 ⁷ The polymer contains at least two repeating units selected from the repeating units represented by the above formula (4), formula (5) and formula (6), and the sum of these repeating units is the polymer. After adding halogen to the carbon-carbon double bond of the vinylene group of the polymer compound that is 50 mol% or more of the above repeating unit, the double bond is converted into an ethynylene bond by dehydrohalogenation treatment. In addition, since the synthesis of the monomer is easy and an electrolysis apparatus is not required, this is an industrially superior method compared to a known method, and is particularly preferable.
[0034]
In this case, the method for halogenation is not particularly limited, but conditions under which the aromatic ring is not substituted with halogen are preferable. For example, a method of adding bromine in an inert organic solvent such as carbon tetrachloride under cooling is exemplified.
[0035]
The method for the dehydrohalogenation treatment is not particularly limited, but a dehydrohalogenation reaction with a base is preferable. For example, a method in which dehydrohalogenation is performed with potassium hydroxide or potassium alcoholate in an alcohol solvent is exemplified.
[0036]
As for the structure of the organic EL device of the present invention, in particular, if a light emitting material comprising the polymer fluorescent material of the present invention is used in a light emitting layer provided between a pair of electrodes, at least one of which is transparent or translucent. There is no limitation, and a known structure is adopted.
For example, a pair of electrodes on both sides of a light emitting layer made of the polymer fluorescent material or a light emitting layer made of a mixture of the polymer fluorescent material and a charge transport material (meaning a generic name of an electron transport material and a hole transport material) An electron transport layer containing an electron transport material adjacent to the light emitting layer, and / or between the anode and the light emitting layer, adjacent to the light emitting layer. Examples are those in which a hole transport layer containing a hole transport material is laminated.
Further, the present invention includes a case where the light emitting layer and the charge transport layer are a single layer and a combination of a plurality of layers. Furthermore, for example, a light emitting material other than the polymeric fluorescent substance described below may be mixed and used in the light emitting layer. Moreover, it can also be set as the layer which disperse | distributed this polymeric fluorescent substance and / or charge transport material to the high molecular compound.
[0037]
As the charge transport material used together with the polymeric fluorescent substance of the present invention, that is, an electron transport material or a hole transport material, known materials can be used, and the hole transport material is not particularly limited. , Stilbene derivatives, triphenyldiamine derivatives, poly (N-vinylcarbazole), polyaniline and its derivatives, polythiophene and its derivatives, poly (p-phenylene vinylene) and its derivatives, poly (2,5-thienylene vinylene) and its Examples of electron transport materials include oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoanthraquinodimethane and its derivatives, fluoreno Derivatives, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, metal complexes of 8-hydroxyquinoline and derivatives thereof.
[0038]
Specifically, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-20988, JP-A-3-37992, The thing etc. which are described in the same 3-152184 gazette are illustrated.
Examples of the hole transport material include triphenyldiamine derivatives, poly (N-vinylcarbazole), and examples of the electron transport material include oxadiazole derivatives, benzoquinone and derivatives thereof, anthraquinone and derivatives thereof, and metal complexes of 8-hydroxyquinoline and derivatives thereof. In particular, 4,4′-bis (N (3-methylphenyl) -N-phenylamino) biphenyl and poly (N-vinylcarbazole) are preferable as the hole transport material, and 2- ( 4-Biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, and tris (8-quinolinol) aluminum are preferred.
Of these, one or both of an electron transporting compound and a hole transporting compound may be used simultaneously. These may be used singly or in combination of two or more.
[0039]
When a charge transport layer is provided between the light-emitting layer and the electrode, the charge transport layer may be formed using these charge transport materials.
In addition, when the charge transport material is mixed with the light emitting layer, the amount of the charge transport material varies depending on the type of the compound used, etc. It may be determined as appropriate in consideration. Usually, it is 1 to 40 weight% with respect to a luminescent material, More preferably, it is 2 to 30 weight%.
[0040]
Although it does not specifically limit as a known luminescent material which can be used with the polymeric fluorescent substance used for this invention, For example, a naphthalene derivative, anthracene and its derivative, perylene and its derivative, a polymethine type, a xanthene type, a coumarin type, a cyanine type etc. And the like, metal complexes of 8-hydroxyquinoline and derivatives thereof, aromatic amines, tetraphenylcyclopentadiene and derivatives thereof, tetraphenylbutadiene and derivatives thereof, and the like can be used. Specifically, known ones such as those described in JP-A-57-51781 and 59-194393 can be used.
[0041]
Next, a typical method for producing the organic EL element of the present invention will be described. As a pair of electrodes composed of an anode and a cathode, a transparent or semi-transparent electrode is formed by forming a transparent or semi-transparent electrode on a transparent substrate such as glass or transparent plastic.
As the material for the anode, a conductive metal oxide film, a translucent metal thin film, or the like is used. Specifically, a film (NESA etc.) made of 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 deposition method, a sputtering method, a plating method, or the like is used.
[0042]
Next, a light emitting layer containing the above polymeric fluorescent substance as a light emitting material is formed on the anode. Examples of the forming method include application methods such as spin coating method, casting method, dipping method, bar coating method, roll coating method using solutions, mixed solutions or melts of these materials. It is particularly preferable to form a film by a coating method such as a spin coating method, a casting method, a dipping method, a bar coating method, or a roll coating method.
[0043]
The thickness of the light emitting layer is preferably 0.5 nm to 10 μm, more preferably 1 nm to 1 μm. The range of 10 to 500 nm is preferable in order to increase the current density and increase the luminous efficiency.
In addition, when thinning by the apply | coating method, in order to remove a solvent, it is desirable to heat-dry at the temperature of 30-200 degreeC under reduced pressure or inert atmosphere, Preferably it is 60-100 degreeC.
[0044]
In addition, when laminating the light-emitting layer and the charge transport layer (which means the generic name of the hole transport layer and the electron transport layer), the hole is formed on the anode before the light-emitting layer is provided by the above film formation method. It is preferable to form a transport layer and / or to form an electron transport layer thereon after providing a light emitting layer.
[0045]
The method for forming the charge transport layer is not particularly limited, but it can be applied by vacuum deposition from a powdered state, or spin coating method after being dissolved in a solution, casting method, dipping method, bar coating method, roll coating method, etc. Or a coating method such as a spin coating method, a casting method, a dipping method, a bar coating method, a roll coating method after the polymer compound and the charge transport material are mixed and dispersed in a solution state or a molten state. it can. The polymer compound to be mixed is not particularly limited, but those that do not extremely inhibit charge transport are preferable, and those that do not strongly absorb visible light are preferably used.
[0046]
For example, poly (N-vinylcarbazole), polyaniline and derivatives thereof, polythiophene and derivatives thereof, poly (p-phenylene vinylene) and derivatives thereof, poly (2,5-thienylene vinylene) and derivatives thereof, polycarbonate, polyacrylate, Examples include polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane. In view of easy film formation, it is preferable to use a coating method.
[0047]
The thickness of the charge transport layer needs to be at least such that no pinholes are generated. However, if the thickness is too large, the resistance of the device increases and a high driving voltage is required, which is not preferable. Therefore, the thickness of the charge transport layer is preferably 0.5 nm to 10 μm, more preferably 1 nm to 1 μm, and particularly preferably 5 to 200 nm.
[0048]
Next, an electrode is provided on the light emitting layer or the electron transport layer. This electrode becomes an electron injection cathode. The material is not particularly limited, but 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, graphite thin film, and the like are used. As a method for producing the cathode, a vacuum deposition method, a sputtering method, or the like is used.
[0049]
【Example】
Examples of the present invention are shown below, but the present invention is not limited to these.
Example 1
<Element structure>
One Example of the organic EL element of this invention is shown. On the glass substrate, an ITO transparent electrode, a hole transport layer, a polymer light emitting layer, an electron transport layer, and a back electrode are laminated.
<Synthesis of polymeric fluorescent substance 1>
2,5-Dioctyloxy-p-xylylene dichloride was reacted with triphenylphosphine in N, N-dimethylformamide to synthesize a phosphonium salt. 9.55 g of the obtained phosphonium salt, 0.67 g of isophthalaldehyde, and 0.67 g of terephthalaldehyde were dissolved in ethyl alcohol. An ethyl alcohol solution containing 1.56 g of lithium ethoxide was dropped into an ethyl alcohol solution of a phosphonium salt and a dialdehyde and polymerized at room temperature for 3 hours. After standing overnight at room temperature, the precipitate was filtered off, washed with ethyl alcohol and dissolved in chloroform. Ethanol was added to this solution for purification by reprecipitation. This was dried under reduced pressure to obtain a polymer.
[0050]
3.0 g of this polymer was dissolved in 120 g of carbon tetrachloride. To this solution, a solution obtained by dissolving 3.1 g of bromine in 20 g of carbon tetrachloride was added dropwise, followed by stirring at room temperature for 2 hours to perform bromination of the polymer. After concentrating this solution at room temperature, ethanol was added thereto, and the produced precipitate was recovered, washed with ethanol, and then dried under reduced pressure to obtain 5 g of a brominated polymer.
Next, dehydrohalogenation reaction was performed. A solution prepared by dissolving 3.14 g of tert-butoxypotassium in 70 g of tert-butanol and heating up to 70 ° C. was dropped into a solution prepared by dissolving 2.73 g of a brominated polymer in 70 g of xylene. Subsequently, the reaction was carried out at 90 ° C. for 7 hours. After cooling this solution, it was poured into a large amount of methanol, and the produced precipitate was recovered. This precipitate was washed with ethanol. Next, this precipitate was dissolved in chloroform. Ethanol was added to this solution for purification by reprecipitation. This was dried under reduced pressure to obtain 0.5 g of a polymer having an ethynylene group. This is called polymeric fluorescent substance 1.
[0051]
The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 1 is 7.0 × 10 ^Four Met. Here, for the number average molecular weight, the number average molecular weight in terms of polystyrene was determined by gel permeation chromatography (GPC) using chloroform as a solvent. The structure of the polymeric fluorescent substance 1 was confirmed by infrared absorption spectrum and NMR.
[0052]
<Measurement of fluorescence intensity>
Polymeric fluorescent substance 1 was dissolved in chloroform. The 0.4% chloroform solution was spin-coated on a quartz plate to obtain a polymer thin film. The fluorescence spectrum of this thin film was measured using a fluorescence spectrophotometer 850 manufactured by Hitachi, Ltd. For calculation of the quantum yield of fluorescence, the fluorescence spectrum when excited at 410 nm was used. The fluorescence intensity was obtained as a relative value by dividing the area of the fluorescence spectrum plotted with the wave number on the horizontal axis by the absorbance at 410 nm. The fluorescence intensity (relative value) of the obtained polymeric fluorescent substance 1 is shown in Table 1.
[0053]
<Creation and evaluation of element>
A glass substrate with an ITO film having a thickness of 40 nm was formed by sputtering using a 1.0 wt% chloroform solution of the polymeric fluorescent substance 1 synthesized in Example 1 to a thickness of 50 nm by spin coating. Subsequently, after drying this at 80 degreeC under pressure reduction for 1 hour, 150 nm of aluminum-lithium alloys (Al: Li = 100: 1 weight ratio) were vapor-deposited on it as a cathode, and the organic EL element was produced. The degree of vacuum during deposition is 8 × 10 ^-6 It was below Torr.
When a voltage is applied to this element, blue-green light emission is observed.
[0054]
Example 2
<Synthesis of polymeric fluorescent substance 2>
2,5-Dioctyloxy-p-xylylene dichloride was reacted with triphenylphosphine in N, N-dimethylformamide to synthesize a phosphonium salt. A dialdehyde compound obtained by reacting 12 g of the obtained phosphonium salt and p-hydroxybenzaldehyde with potassium hydroxide in an ethyl alcohol solvent to form potassium phenolate, and then reacting with 1,6-dibromomethane-hexane. 2.05 g and 0.85 g of isophthalaldehyde were dissolved in an ethyl alcohol / chloroform mixed solvent. An ethyl alcohol solution containing 1.56 g of lithium ethoxide was dropped into an ethyl alcohol / chloroform solution of a phosphonium salt and a dialdehyde and polymerized at room temperature for 3 hours. After standing overnight at room temperature, the precipitate was filtered off, washed with ethyl alcohol and dissolved in chloroform. Ethanol was added to this solution for purification by reprecipitation. This was dried under reduced pressure to obtain a polymer.
5.0 g of this polymer was dissolved in 120 g of carbon tetrachloride. To this solution, a solution obtained by dissolving 4.2 g of bromine in 20 g of carbon tetrachloride was added dropwise, followed by stirring at room temperature for 2 hours to perform bromination of the polymer. After concentrating this solution at room temperature, ethanol was added thereto, and the produced precipitate was recovered, washed with ethanol, and then dried under reduced pressure to obtain 8.9 g of a brominated polymer.
[0055]
Next, dehydrohalogenation reaction was performed. A solution prepared by dissolving 4.48 g of tert-butoxypotassium in 70 g of tert-butanol and heating up to 70 ° C. was added dropwise to a solution prepared by dissolving 4.46 g of the brominated polymer in 80 g of xylene. Subsequently, the reaction was carried out at 90 ° C. for 7 hours. After cooling this solution, it was poured into a large amount of methanol, and the produced precipitate was recovered. This precipitate was washed with ethanol. Next, this precipitate was dissolved in chloroform. Ethanol was added to this solution for purification by reprecipitation. This was dried under reduced pressure to obtain 0.9 g of a polymer having an ethynylene group. This is called polymeric fluorescent substance 2.
The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 2 is 2.0 × 10 ^Four Met. Here, for the number average molecular weight, the number average molecular weight in terms of polystyrene was determined by gel permeation chromatography (GPC) using chloroform as a solvent. The structure of the polymeric fluorescent substance 2 was confirmed by infrared absorption spectrum and NMR.
[0056]
<Measurement of fluorescence intensity>
Table 1 shows the fluorescence intensity (relative value) of the polymeric fluorescent substance 2 obtained by measurement in the same manner as in Example 1.
[0057]
<Creation and evaluation of element>
A glass substrate with an ITO film having a thickness of 40 nm was formed by sputtering using a 1.0 wt% chloroform solution of polymeric fluorescent substance 2 synthesized in Example 2 to a thickness of 50 nm by spin coating. Subsequently, after drying this at 80 degreeC under pressure reduction for 1 hour, 150 nm of aluminum-lithium alloys (Al: Li = 100: 1 weight ratio) were vapor-deposited on it as a cathode, and the organic EL element was produced. The degree of vacuum during deposition is 8 × 10 ^-6 It was below Torr.
When voltage is applied to this element, blue light emission is observed.
[0058]
Comparative Example 1
<Synthesis of polymeric fluorescent substance 3>
A solution of 6.7 g of tert-butoxy potassium in 70 g of tert-butyl alcohol was heated to about 70 ° C., and 8.6 g of 2,5-dioctyloxy-p-xylylene dichloride was dissolved in 80 g of xylene. After dropping the liquid, the reaction was carried out at about 90 ° C. for 7 hours. After cooling the solution, it was poured into a large amount of methanol and a red precipitate was formed. After collecting this precipitate, it was washed with methanol, subsequently washed with an ethanol / water mixed solvent, and further washed with ethanol. Next, this precipitate was dissolved in chloroform. Ethanol was added to this solution for purification by reprecipitation. This was dried under reduced pressure to obtain poly (2,5-dioctyloxy-p-phenylenevinylene).
1.07 g of this polymer was dissolved in 50 g of carbon tetrachloride. A solution prepared by dissolving 1 g of bromine in 10 g of carbon tetrachloride was added dropwise to this solution, followed by stirring at room temperature for 2 hours to perform bromination of the polymer. Ethanol was added to this solution, and the produced precipitate was collected, washed with ethanol, and then dried under reduced pressure to obtain a brominated polymer.
Next, dehydrohalogenation reaction was performed. A solution of 1.02 g of brominated polymer in 30 g of xylene was added dropwise to a solution in which tertiary butoxy potassium was dissolved in tertiary butanol and the temperature was raised to 70 ° C. Subsequently, the reaction was carried out at 90 ° C. for 7 hours. After cooling this solution, it was poured into a large amount of methanol, and the produced precipitate was recovered. This precipitate was washed with ethanol and then dried under reduced pressure to obtain 0.2 g of a polymer having an ethynylene group. This is called polymeric fluorescent substance 3.
[0059]
The number average molecular weight in terms of polystyrene of the polymeric fluorescent substance 3 is 1.8 × 10 ^Four Met. Here, for the number average molecular weight, the number average molecular weight in terms of polystyrene was determined by gel permeation chromatography (GPC) using chloroform as a solvent. The structure of the polymeric fluorescent substance 3 was confirmed by infrared absorption spectrum and NMR.
[0060]
<Measurement of fluorescence intensity>
Table 1 shows the fluorescence intensity (relative value) of the polymeric fluorescent substance 3 obtained by measurement in the same manner as in Example 1.
The fluorescent intensity of the polymeric fluorescent substances 1 and 2 was strong as shown in Table 1.
[Table 1]

[0061]
【The invention's effect】
The polymeric fluorescent substance of the present invention has a high fluorescence quantum yield and is soluble in a solvent, and can be suitably used as a light emitting material for an organic EL device, a dye for a dye laser, and the like. Moreover, since a light emitting layer can be easily formed by the apply | coating method, an organic EL element can be produced easily.
Furthermore, since the organic EL element using the polymer light emitter of the present invention uses a thermally stable polymer fluorescent material, it is preferably used as an apparatus such as a planar light source as a backlight or a flat panel display. it can.

Claims (9)

The polymer is soluble in an organic solvent, and the polymer has a number average molecular weight of 10 ³ to 10 ^{7. The} polymer is represented by the following formulas (1), (2), and (3). A polymeric fluorescent substance comprising at least two repeating units selected from repeating units, wherein the sum of these repeating units is 50 mol% or more of the repeating units of the polymer.
[Chemical 1]
-Ar ₁ -C≡C- (1)
[Chemical 2]
—Ar ₂ —C≡C— (2)
[Chemical 3]
_{-Ar 3 - (X 1) m} -R 1 - (X 2) n -Ar 4 -C≡C- (3)
(In the formula, Ar1 consists of an aromatic compound group in which the number of carbon atoms involved in the conjugated bond is 6 or more and 22 or less, or a carbon number of 4 or more and 20 or less that contains a hetero atom involved in the conjugated bond. Selected from heterocyclic compound groups of 5 or more members, and presents continuously in the shortest path between two carbon atoms in Ar ₁ bonded to two groups adjacent to Ar ₁ in the chemical structural formula of these groups The total number of carbon atoms and nitrogen atoms is an even number.
Ar ₂ is an aromatic compound group having 6 to 22 carbon atoms involved in the conjugated bond or a 6-membered ring or more containing 4 to 20 carbon atoms containing a hetero atom involved in the conjugated bond. Carbon atoms present in succession in the shortest path between the two carbon atoms in Ar ₂ bonded to two groups adjacent to Ar ₂ in the chemical structural formulas of these groups The number of nitrogen atoms is 1, 3 or 5.
Ar ₃ and Ar ₄ are each independently a group selected from the group consisting of an aromatic group having 4 to 20 carbon atoms involved in the conjugated bond or a heterocyclic compound group.
R ₁ is a hydrocarbon group having 1 to 22 carbon atoms or a heterocyclic compound group having 4 to 22 carbon atoms, and X ₁ and X ₂ are each independently —O— , —COO— or —OCO—. M and n are 1 . ) R ₁ The polymeric fluorescent substance according to claim 1, wherein is a hydrocarbon group having 1 to 22 carbon atoms. X ₁ And X ₂ Is -O- 1 Or the polymeric fluorescent substance according to 2. Polymer, alternating copolymer, the polymeric fluorescent substance according to claim 1, characterized in that it is a random copolymer or a block copolymer. It is a polymer soluble in an organic solvent, and the polymer has a number average molecular weight of 10 3 to 10 7, and the polymer is represented by the following formulas (4), (5) and (6) A halogen is added to the carbon-carbon double bond of the vinylene group of the polymer compound containing at least two repeating units selected from the units, and the sum of these repeating units is 50 mol% or more of the repeating unit of the polymer. The method for producing a polymeric fluorescent substance according to any one of claims 1 to 4, wherein the double bond is converted into an ethynylene bond by dehydrohalogenation treatment.
[Formula 4]
—Ar ₁ —CH═CH— (4)
[Chemical formula 5]
—Ar ₂ —CH═CH— (5)
[Chemical 6]
_{-Ar 3 - (X 1) m} -R 1 - (X 2) n -Ar 4 -C = C- (6)
(In the formula, Ar ₁ , Ar ₂ , Ar ₃ , Ar ₄ , R ₁ , X ₁ , X ₂ , m, and n are the same as defined in claim 1). The polymer fluorescent light according to any one of claims 1 to 4 , wherein in the organic electroluminescence device having at least a light-emitting layer between a pair of anode and cathode electrodes, at least one of which is transparent or translucent, the light-emitting layer. An organic electroluminescence device comprising a body. 7. The organic electroluminescence device according to claim 6 , further comprising a layer containing an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer. 7. The organic electroluminescence device according to claim 6 , further comprising a layer containing a hole transporting compound adjacent to the light emitting layer between the anode and the light emitting layer. 7. The organic electroluminescent device according to claim 6 , further comprising: a layer containing an electron transporting compound adjacent to the light emitting layer between the cathode and the light emitting layer; and the light emitting layer between the anode and the light emitting layer. An organic electroluminescence device comprising a layer containing a hole transporting compound adjacent to the organic electroluminescence device.