JP2004030942A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element with a large luminous strength, high luminous efficiency, long element life and easy to manufacture with the use of load transport polyether excellent in thermal stability, preservation stability, and solubility and compatibility to a solvent or a resin. <P>SOLUTION: With the electroluminescent element composed of one or a plurality of organic compound layers pinched between a pair of electrodes consisting of a positive and a negative electrodes at least either being transparent or translucent, at least one of the organic compound layers contains one or more kinds of load transport polyether consisting of a repetition unit containing as a partial structure at least one kind selected from structures expressed in formulae (I-1) and (I-2). Provided, in formulae (I-1) and (I-2), Ar represents a substituent expressed in formula (II-1) or (II-2). <P>COPYRIGHT: (C)2004,JPO

Description

【００１２】
（一般式（Ｉ−１）および（Ｉ−２）式中、Ｘは置換もしくは未置換の２価のベンゼン基、置換もしくは未置換の芳香環数２〜１０の１価の多核芳香族炭化水素、置換もしくは未置換の芳香環数２〜１０の１価の縮合芳香族炭化水素、または置換もしくは未置換の１価の芳香族複素環を表す。Ｔは炭素数１〜６の２価の直鎖状炭化水素基または炭素数２〜１０の２価の分枝鎖状炭化水素基を表す。ｍは０〜３の整数を表す。ｋは０または１を表す。Ａｒは下記一般式（ＩＩ−１）または（ＩＩ−２）で表される置換基を表す。
【００１３】
【化５】

【００１４】
（一般式（ＩＩ−１）および（ＩＩ−２）中、Ａｒ_１は、置換もしくは未置換の１価のベンゼン環、置換もしくは未置換の芳香族数２〜１０の１価の多核芳香族炭化水素、置換もしくは未置換の芳香族環数２〜１０の１価の縮合多環芳香族炭化水素、置換もしくは未置換の１価の芳香族複素環、または少なくとも１種の芳香族複素環を含む１価の置換基を表す。Ａｒ２、Ａｒ_３およびＡｒ_４は、各々独立に、置換もしくは未置換の２価のベンゼン環、置換もしくは未置換の芳香族数２〜１０の２価の多核芳香族炭化水素、置換もしくは未置換の芳香族環数２〜１０の２価の縮合多環芳香族炭化水素、置換もしくは未置換の２価の芳香族複素環、または少なくとも１種の芳香族複素環を含む置換もしくは２価の置換基を表す。Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は、各々独立に、水素原子、アルキル基、シアノ基、ハロゲン基、置換アミノ基、置換もしくは未置換のアリール基、または置換もしくは未置換のアラルキル基を表し、Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は同一であっても異なっていてもよい。ｎは０〜１０の整数を表す。）
【００１５】
この電荷輸送性ポリエーテルとしては、下記一般式（ＩＩＩ）で示されるポリエーテルを好適に挙げることができる。
【００１６】
【化６】

【００１７】
（一般式（ＩＩＩ）中、Ａは上記一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも１種を表す。Ｒは水素原子、アルキル基、置換もしくは未置換のアリール基、または置換もしくは未置換のアラルキル基を表す。ｐは５〜５，０００の整数を表す。）
【００１８】
本発明の有機電界発光素子を構成する有機化合物層は、大きく分類して電荷輸送機能を持つ発光層のみから構成される単層構成、あるいは少なくとも発光層または電荷輸送を持つ発光層を含む相互に異なる機能を有する複数の層から構成される機能分離型の複数層構成からなる。この機能分離型の複数層構成としては、例えば▲１▼発光層及び電子輸送層（以下、「層構成（１）」と略す場合がある）、▲２▼正孔輸送層、発光層及び電子輸送層（以下、「層構成（２）」と略す場合がある）、▲３▼正孔輸送層及び電荷輸送能を持つ発光層（以下、「層構成（３）」と略す場合がある）が挙げられる。この構成において、正孔注入層は正孔輸送層に、電子注入層は電子輸送層に含める。また、層構成はこれに限定するものではない。
【００１９】
前記有機化合物層が電荷輸送機能を持つ発光層のみから構成される場合には、該電荷輸送機能を持つ発光層には、前記一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも１種を部分構造として含む繰り返し単位よりなる電荷輸送性ポリエーテルを含有する。
一方、前記有機化合物層が機能分離型の複数層から構成される場合には、層構成（１）においては、発光層及び電子輸送層の少なくとも一方に前記電荷輸送性ポリエーテルが含有され、層構成（２）においては、正孔輸送層及び電子輸送層の少なくとも一方に前記電荷輸送性ポリエーテルが含有され、層構成（３）においては、正孔輸送層及び電荷輸送機能を持つ発光層の少なくとも一方に前記電荷輸送性ポリエーテルが含有される。
前記有機化合物層は、前記電荷輸送性ポリエーテル以外の電荷輸送材料（正孔輸送材料、電子輸送材料）を更に含んでいてもよい。
【００２０】
【発明の実施の形態】
本発明の有機電界発光素子は、少なくとも一方が透明または半透明である陽極および陰極よりなる一対の電極間に挾持された一つまたは複数の有機化合物層より構成され、該有機化合物層の少なくとも一層が、下記一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも１種を部分構造として含む繰り返し単位よりなる電荷輸送性ポリエーテルを１種以上含有する。
【００２１】
この電荷輸送性ポリエーテルは、発光時の熱安定性、溶剤や樹脂に対する溶解性及び相溶解性に優れており、さらに、本発明の有機電界発光素子は、前記電荷輸送性ポリエーテルを含有してなる有機化合物層を含んでなるため、発光強度が大きく、発光効率が高く、素子寿命が長く、且つ製造が容易である。
【００２２】
【化７】

【００２３】
一般式（Ｉ−１）および（Ｉ−２）中、Ｘは、置換もしくは未置換の２価のベンゼン基、置換もしくは未置換の芳香環数２〜１０の１価の多核芳香族炭化水素、置換もしくは未置換の芳香環数２〜１０の１価の縮合芳香族炭化水素、または、置換もしくは未置換の１価の芳香族複素環を表す。
【００２４】
一般式（Ｉ−１）および（Ｉ−２）中、Ａｒは、一般式（ＩＩ−１）または（ＩＩ−２）で表される置換基を表す。
【００２５】
【化８】

【００２６】
一般式（ＩＩ−１）および（ＩＩ−２）中、Ａｒ_１は、置換もしくは未置換の１価のベンゼン環、置換もしくは未置換の芳香族数２〜１０の１価の多核芳香族炭化水素、置換もしくは未置換の芳香族環数２〜１０の１価の縮合多環芳香族炭化水素、置換もしくは未置換の１価の芳香族複素環、または少なくとも１種の芳香族複素環を含む１価の置換基を表す。Ａｒ２、Ａｒ_３およびＡｒ_４は、各々独立に、置換もしくは未置換の２価のベンゼン環、置換もしくは未置換の芳香族数２〜１０の２価の多核芳香族炭化水素、置換もしくは未置換の芳香族環数２〜１０の２価の縮合多環芳香族炭化水素、置換もしくは未置換の２価の芳香族複素環、または少なくとも１種の芳香族複素環を含む置換もしくは２価の置換基を表す。Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は、各々独立に、水素原子、アルキル基、シアノ基、ハロゲン基、置換アミノ基、置換もしくは未置換のアリール基、または置換もしくは未置換のアラルキル基を表し、Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は同一であっても異なっていてもよい。ｎは０〜１０の整数を表す。
【００２７】
上記Ｘ、Ａｒ_１、Ａｒ_２、Ａｒ_３およびＡｒ_４を表す構造として選択される１価あるいは２価の多核芳香族炭化水素および縮合多環芳香族炭化水素としては、特に限定されず、任意の構造を有することができる。
【００２８】
ここで、当該多核芳香族炭化水素及び縮合芳香族炭化水素とは、本発明においては、具体的には以下に定義されることを意味する。
すなわち、「多核芳香族炭化水素」とは、炭素と水素から構成される芳香環が２個以上存在し、環同士が炭素―炭素結合によって結合している炭化水素を表す。具体的には、ビフェニル、ターフェニル等が挙げられる。また、「縮合芳香族炭化水素」とは、炭素と水素から構成される芳香環が２個以上存在し、環同士が１対の炭素原子を共有している炭化水素を表す。具体的には、ナフタレン、アントラセン、フェナントレン、フルオレン等が挙げられる。また、複素環は、その環骨格を構成する原始（Ｎｒ）は、Ｎｒ＝５及び／又は６が好ましく用いられる。また、環骨格を構成する炭素原子以外の原子（異種原子）の種類及び数は特に限定されないが、例えば、硫黄原子、窒素原子、酸素原子等が好ましく用いられ、前記環骨格中には２種類以上及び／又は２個以上の異種原子が含まれてもよい。特に５員環構造をもつ複素環として、チオフェン、ピロール及びフラン、または前記化合物の３位並び４位の炭素を窒素で置き換えた複素環が好ましく用いられ、６員環構造を持つ複素環として、ピリジンが好ましく用いられる。
【００２９】
上記Ｘ、Ａｒ_１、Ａｒ_２、Ａｒ_３およびＡｒ_４を表す構造に置換され得る置換基としては、水素原子、アルキル基、アルコキシ基、アリール基、アラルキル基、置換アミノ基、ハロゲン原子等が挙げられる。アルキル基としては、炭素数１〜１０のものが好ましく、例えば、メチル基、エチル基、プロピル基、イソプロピル基等が挙げられる。アルコキシル基としては、炭素数１〜１０のものが好ましく、例えば、メトキシ基、エトキシ基、プロポキシ基、イソプロポキシ基等が挙げられる。アリール基としては、炭素数６〜２０のものが好ましく、例えば、フェニル基、トルイル基等が挙げられる、アラルキル基としては、炭素数７〜２０のものが好ましく、例えば、ベンジル基、フェネチル基等が挙げられる。置換アミノ基の置換基としては、アルキル基、アリール基、アラルキル基等が挙げられ、具体例は前述の通りである。
【００３０】
上記Ｘ、Ａｒ_１、Ａｒ_２、Ａｒ_３およびＡｒ_４を表す構造として、具体的には下記の式（１）〜（１３）から選択された基が好適に挙げられる。なお、１価の基の場合は、下記具体例のいずれか１つの水素基が離脱した構造であり、２価の基の場合、下記具体例のいずれか２つの水素基が離脱した構造である。
【００３１】
【化９】

【００３２】
式（１）〜（１３）中、Ｒ_５からＲ_２０は、水素原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシル基、置換もしくは未置換のフェニル基、置換もしくは未置換のアラルキル基、またはハロゲン原子を表す。Ｒ_７は水素原子、アルキル基、シアノ基を表す。ａは０または１を意味し、ｂは０〜１０の整数を意味する。Ｖは下記の式（１４）〜（３４）から選択された基を表す。
【００３３】
【化１０】

【００３４】
式（１４）〜（３３）中、Ｒ_２１〜Ｒ_２３は、水素原子、炭素数１〜１０のアルキル基、炭素数１〜１０のアルコキシル基、置換もしくは未置換のフェニル基、または置換もしくは未置換のアラルキル基、またはハロゲン原子を表す。Ｒ_７は水素原子、アルキル基、シアノ基を表す。ｃは０〜１０の整数を意味する。
【００３５】
一般式（Ｉ−１）および（Ｉ−２）中、Ｔは、炭素数１〜６の２価の直鎖状炭化水素基または炭素数２〜１０の２価の分枝鎖状炭化水素基を表し、好ましくは炭素数が２〜６の２価の直鎖状炭化水素基および炭素数３〜７の２価の分枝鎖状炭化水素基より選択される。具体的な構造を以下に示す。
【００３６】
【化１１】

【００３７】
以下、一般式（Ｉ−１）〜（Ｉ−２）で示される構造の具体例を示すが、本発明はこれに限定されるわけではない。なお、構造番号１〜１２４は、一般式（Ｉ−１）で示される構造の具体例であり、構造番号１２５〜２１３は、一般式（Ｉ−２）で示される構造の具体例である。
【００３８】
【表１】

【００３９】
【表２】

【００４０】
【表３】

【００４１】
【表４】

【００４２】
【表５】

【００４３】
【表６】

【００４４】
【表７】

【００４５】
【表８】

【００４６】
【表９】

【００４７】
【表１０】

【００４８】
【表１１】

【００４９】
【表１２】

【００５０】
【表１３】

【００５１】
【表１４】

【００５２】
【表１５】

【００５３】
【表１６】

【００５４】
【表１７】

【００５５】
【表１８】

【００５６】
一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも一種を部分構造として繰り返し単位よりなる電荷輸送性ポリエーテルとしては、下記一般式（ＩＩＩ）で示されるものが好適に使用される。
【００５７】
【化１２】

【００５８】
一般式（ＩＩＩ）中、Ａは上記一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも１種を表し、一つのポリマー中に２種類以上の構造Ａが含まれてもよい。
【００５９】
一般式（ＩＩＩ）中、Ｒは水素原子、アルキル基、置換もしくは未置換のアリール基、または置換もしくは未置換のアラルキル基を表す。アルキル基としては、炭素数１〜１０のものが好ましく、例えば、メチル基、エチル基、プロピル基、イソプロピル基等が挙げられる。アリール基としては、炭素数６〜２０のものが好ましく、例えば、フェニル基、トルイル基等が挙げられる、アラルキル基としては、炭素数７〜２０のものが好ましく、例えば、ベンジル基、フェネチル基等が挙げられる。また、置換アリール基、置換アラルキル基の置換基としては、水素原子、アルキル基、アルコキシ基、置換アミノ基、ハロゲン原子等が挙げられる。ｍは、１〜５の整数を表す。
【００６０】
一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも一種を部分構造として繰り返し単位よりなる電荷輸送性ポリエーテルの重量平均分子量Ｍｗは、５０００〜３０００００の範囲にあるものが好ましい。
【００６１】
以下、一般式（ＩＩＩ）で示される上記の電荷輸送性ポリエーテルの具体例を示すが、本発明はこれらの具体例に限定されるものではない。尚、表における、モノマーの欄の番号は、前記一般式（Ｉ−１）および（Ｉ−２）で示される構造の具体例である構造番号に対応している。また、ｍは一般式（Ｉ−１）および（Ｉ−２）におけるｍを意味する。以下、各番号を付した具体例（化合物）、例えば１５の番号を付した具体例は例示化合物（１５）という。
【００６２】
【表１９】

【００６３】
【表２０】

【００６４】
一般式（Ｉ−１）および（Ｉ−２）で示される構造から選択された少なくとも一種を部分構造として繰り返し単位よりなる電荷輸送性ポリエーテルは、例えば、下記一般式（ＩＶ−１）および（ＩＶ−２）で示されるヒドロキシル基を有する電荷輸送性化合物をを分子間で縮合させることによって、容易に製造することができる。ここで、下記一般式（ＩＶ−１）および（ＩＶ−２）におけるＡｒ、Ｘ、Ｔ、ｍ、ｋは、前記一般式（Ｉ−１）および（Ｉ−２）におけるＡｒ、Ｘ、Ｔ、ｍ、ｋと同義である。
【００６５】
【化１３】

【００６６】
具体的には前記電荷輸送性ポリエーテルは、例えば、以下のように合成することができる。
１）上記電荷輸送性ポリエーテルは、上記一般式（ＩＶ−１）および（ＩＶ−２）のうち２個のヒドロキシアルキル基を有する電荷輸送性化合物（以下、電荷輸送性モノマー（ＩＶ）と略す）を加熱脱水縮合する方法によってを合成することができる。この場合、無溶媒で電荷輸送性モノマー（ＩＶ）を加熱溶融し、水の脱離による重合反応を促進させるため減圧下で反応させることが望ましい。また、溶媒を使用する場合は、水の除去のため、水と共沸する溶媒、例えば、トリクロロエタン、トルエン、クロロベンゼン、ジクロロベンゼン、ニトロベンゼン、１−クロロナフタレン等が有効であり、電荷輸送性モノマー（ＩＶ）１当量に対して、１〜１００当量、好ましくは２〜５０当量の範囲で用いられる。反応温度は任意に設定できるが、重合中に生成する水を除去するために、溶媒の沸点で反応させるのが好ましい。重合が進まない場合には、反応系から溶媒を除去し、粘ちょう状態で加熱撹拌してもよい。
【００６７】
２）上記電荷輸送性ポリエーテルは、酸触媒として、ｐ−トルエンスルホン酸、塩酸、硫酸、トリフルオロ酢酸等のプロトン酸、あるいは塩化亜鉛等のルイス酸を用い脱水縮合する方法によって合成することもできる。この場合、電荷輸送性モノマー（ＩＶ）１当量に対して、酸触媒を１〜１／１００００〜１／１０当量、好ましくは１／１０００〜１／５０当量の範囲で用いる。重合中に生成する水を除去するために、水と共沸可能な溶剤を用いるのが好ましい。溶剤としては、トルエン、クロロベンゼン、ジクロロベンゼン、ニトロベンゼン、１−クロロナフタレン等が有効であり、電荷輸送性モノマー（ＩＶ）１当量に対して、１〜１００当量、好ましくは２〜５０当量の範囲で用いられる。反応温度は任意に設定できるが、重合中に生成する水を除去するために、溶剤の沸点で反応させることが好ましい。
【００６８】
３）上記電荷輸送性ポリエーテルは、イソシアン化シクロヘキシル等のイソシアン化アルキル、シアンン化シクロヘキシル等のイソシアン化アルキル、シアン酸ｐ−トリルや２，２−ビス（４−シアナートフェニル）プロパン等のシアン酸エステル、ジクロロヘキシルカルボジイミド（ＤＣＣ）、トリクロロアセトニトリル等の縮合剤を用いる方法によっても合成することができる。この場合、縮合剤は、電荷輸送性モノマー（ＩＶ）１当量に対して、１／２〜１０当量、好ましくは１〜３当量の範囲で用いられる。溶剤として、トルエン、クロロベンゼン、ジクロロベンゼン、１−クロロナフタレン等が有効であり、電荷輸送性モノマー（ＩＶ）１当量に対して、１〜１００当量、好ましくは２〜５０当量の範囲で用いられる。反応温度は任意に設定できるが、室温から溶剤の沸点で反応させることが好ましい。
【００６９】
上記１）、２）および３）の合成法のうち、異性化や副反応が起こりにくいことから、合成法１）または３）が好ましい。特に、合成法３）は反応条件がより穏和なことからより好ましい。
反応終了後、溶剤を用いなかった場合は溶解可能な溶剤に溶解させる。溶剤を用いた場合には、そのまま、メタノール、エタノール等のアルコール類や、アセトン等の電荷輸送性ポリマーが溶解しにくい貧溶剤中に滴下し、電荷輸送性ポリマーを析出させ、電荷輸送性ポリマーを分離した後、水や有機溶剤で十分に洗浄し、乾燥させる。さらに必要であれば、適当な有機溶剤に溶解させ、貧溶剤中に滴下し、電荷輸送性ポリマーを析出させる再沈澱処理を繰り返してもよい。再沈澱処理の際には、メカニカルスターラー等で、効率よく撹拌しながら行うことが好ましい。再沈澱処理の際に電荷輸送性ポリマーを溶解させる溶剤は、電荷輸送性ポリマー１当量に対して、１〜１００当量、好ましくは２〜５０当量の範囲で用いられる。また、貧溶剤は電荷輸送性ポリマー１当量に対して、１〜１０００当量、好ましくは１０〜５００当量の範囲で用いられる。さらに、上記反応において、電荷輸送性モノマーを２種以上、好ましくは２〜５種、さらに好ましくは２〜３種用いることにより、共重合ポリマーの合成も可能である。異種の電荷輸送性モノマーを共重合することによって、電気特性、成膜性、溶解性および蛍光特性を制御することができる。
【００７０】
電荷輸送性ポリエーテルの重合度は、低すぎると成膜性に劣り、強固な膜が得られにくく、また、高すぎると溶剤への溶解度が低くなり、加工性が悪くなるため、５〜５０００の範囲に設定され、好ましくは１０〜３０００、より好ましくは１５〜１０００の範囲である。
【００７１】
電荷輸送性ポリエーテルの末端基は、電荷輸送性モノマーと同様にヒドロキシル基、すなわち末端基Ｒが水素原子であってよいが、溶解性、成膜性、モビリティー等のポリマー物性に影響を及ぼす場合には、末端基Ｒを修飾し物性を制御することができる。例えば、末端のヒドロキシル基を、硫酸アルキル、ヨウ化アルキル等でアルキルエーテル化することができる。具体的な試薬としては、硫酸ジメチル、硫酸ジエチル、ヨウ化メチル、ヨウ化エチル等から任意に選ぶことができ、末端のヒドロキシル基に対し１〜３当量、好ましくは１〜２当量の範囲で用いる。その際、塩基触媒を用いることができるが、塩基触媒として、水酸化ナトリウム、水酸化カリウム、水素化ナトリウム、ナトリウム金属等から任意に選ぶことができ、末端のヒドロキシル基に対し〜３当量、好ましくは１〜２当量の範囲で用いる。反応温度は、０℃から使用する溶剤の沸点で行うことができる。また、その際用いる溶剤として、ベンゼン、トルエン、塩化メチレン、テトラヒドロフラン、Ｎ，Ｎ−ジメチルホルムアミド、ジメチルスルホキシド、Ｎ−メチルピロリドン、１，３−ジメチル−２−イミダゾリジノン等の不活性溶剤から選んだ単独溶剤、あるいは２〜３種の混合溶剤が使用できる。
【００７２】
また、反応によっては、相間移動触媒としてテトラ−ｎ−ブチルアンモニウムアイオダイド等の第４級アンモニウム塩を使用することもできる。また、末端のヒドロキシル基を酸ハロゲン化物を用いアシル化して、末端基Ｒをアシル基にすることもできる。酸ハロゲン化物は特に限定するものではないが、例えばアクリロイルクロリド、クロトノイルクロリド、メタクリロイルクロリド、ｎ−ブチルクロリド、２−フロイルクロリド、ベンゾイルクロリド、シクロヘキサンカルボニルクロリド、エナンチルクロリド、フェニルアセチルクロリド、ｏ−トルオイルクロリド、ｍ−トルオイルクロリド、ｐ−トルオイルクロリド等があげられ、末端のヒドロキシル基に対し１〜３当量、好ましくは１〜２当量の範囲で用いる。その際、塩基触媒を用いることができるが、塩基触媒としては、ピリジン、ジメチルアミノピリジン、トリメチルアミン、トリエチルアミン等から任意に選ぶことができ、酸クロリドに対し１〜３当量、好ましくは１〜２当量の範囲で用いる。その際用いる溶剤として、ベンゼン、トルエン、塩化メチルン、テトラヒドロフラン、メチルエチルケトン等があげられる。反応は、０℃から溶剤の沸点で行うことができる。好ましくは、０℃から３０℃の範囲で行う。さらに、無水酢酸等の酸無水物を用いてもアシル化することができる。溶剤を用いる場合は、具体的には、ベンゼン、トルエン、クロロベンゼン等の不活性溶剤を使用することができる。反応は、０℃から溶剤の沸点で行うことができる。好ましくは、４０℃から溶剤の沸点で行えばよい。
【００７３】
そのほか、モノイソシアネートを用い、末端にウレタン残基（−ＣＯＮＨ−Ｒ′）を導入することができる。具体的なモノイソシアネートとしては、イソシアン酸ベンジルエステル、イソシアン酸ｎ−ブチルエステル、イソシアン酸ｔ−ブチルエステル、イソシアン酸シクロヘキシルエステル、イソシアン酸２，６−ジメチルエステル、イソシアン酸エチルエステル、イソシアン酸イソプロピルエステル、イソシアン酸２−メトキシフェニルエステル、イソシアン酸４−メトキシフェニルエステル、イソシアン酸ｎ−オクタデシルエステル、イソシアン酸フェニルエステル、イソシアン酸ｉ−プロピルエステル、イソシアン酸ｍ−トリルエステル、イソシアン酸ｐ−トリルエステル、イソシアン酸１−ナフチルエステル等から任意に選ぶことができ、末端のヒドロキシル基に対し１〜３当量、好ましくは１〜２当量の範囲で用いる。その際用いる溶剤として、ベンゼン、トルエン、クロロベンゼン、ジクロロベンゼン、塩化メチレン、テトラヒドロフラン、Ｎ，Ｎ−ジメチルホルムアミド、ジメチルスルホキシド、Ｎ−メチルピロリドン、１，３−ジメチル−２−イミダゾリジノン等をあげることができる。反応温度は、０℃から使用溶剤の沸点で行うことができる。反応が進みにくい場合は、ジラウリン酸ジブチルスズ（ＩＩ）、オクチル酸スズ（ＩＩ）、ナフテン酸鉛等の金属化合物、あるいはトリエチルアミン、トリメチルアミン、ピリジン、ジメチルアミノピリジン等の３級アミンを触媒として添加することもできる。
【００７４】
次に、本発明の有機電界発光素子の層構成について詳記する。
本発明の有機電界発光素子は、少なくとも一方が透明または半透明である一対の電極と、それら電極間に挾持された発光層を含む一つまたは複数の有機化合物層により構成され、該有機化合物層の少なくとも１層に前記電荷輸送性ポリエーテルを含有してなる。
【００７５】
本発明の有機電界発光素子においては、有機化合物層が単層の場合は、有機化合物は電荷輸送能を持つ発光層を意味し、該発光層が前記電荷輸送性ポリエーテルを含有してなる。
一方、有機化合物層が複数層構成の場合（即ち、各層が異なる機能を有する機能分離型の場合）は、少なくとも一層が発光層あるいは電荷輸送能を持つ発光層からなる。この場合、該発光層あるいは該電荷輸送能を持つ発光層と、その他の層からなる層構成は、発光層及び電子輸送層から構成される層構成（１）、正孔輸送層、発光層及び電子輸送層から構成される層構成（２）、正孔輸送層及び電荷輸送能を持つ発光層から形成される層構成（３）が挙げれられ、これら層構成（１）〜（３）の発光層及び電荷輸送能を持つ発光層以外の層は、電荷輸送層として機能を有する。この構成において、正孔注入層は正孔輸送層に、電子注入層は電子輸送層に含める。
【００７６】
なお、層構成（１）において、発光層及び電子輸送層の少なくとも一方に前記電荷輸送性ポリエーテルが含有され、層構成（２）においては、正孔輸送層及び電子輸送層の少なくとも一方に前記電荷輸送性ポリエーテルが含有され、層構成（３）においては、正孔輸送層及び電荷輸送能を持つ発光層の少なくとも一方に前記電荷輸送性ポリエーテルが含有される。
【００７７】
また、前記電荷輸送能を持つ発光層、正孔輸送層及び電子輸送層には、前記電荷輸送性ポリエーテル以外の電荷輸送性化合物（正孔輸送材料、電子輸送材料）を更に含んでもよい。詳しくは、後述する。
【００７８】
以下、図面を参照しつつ、より詳細に説明するが、これに限定されるわけではない、
図１〜図４は、本発明の有機電界発光素子の層構成を説明するための模式的断面図であって、図１、図２、図４の場合は、有機化合物層が複数の場合の一例であり、図３の場合は，有機化合物層が１つの場合の例を示す。なお、図１〜図４において、同様の機能を有するものは同じ符号を付して説明する。
【００７９】
図１に示す有機電界発光素子は、透明絶縁体基板１上に、透明電極２、発光層４、電子輸送層５及び背面電極７を順次積層してなる。図２に示す有機電界発光素子は、透明絶縁体基板１上に、透明電極２、正孔輸送層３、発光層４、電子輸送層５及び背面電極７を順次積層してなる。図３に示す有機電界発光素子は、透明絶縁体基板１上に、透明電極２、電荷輸送能を持つ発光層６及び背面電極７を順次積層してなる。図４に示す有機電界発光素子は、透明絶縁体基板１上に、透明電極２、正孔輸送層３、電荷輸送能を持つ発光層６、及び背面電極７を順次積層してなる。以下、各々を詳しく説明する。
【００８０】
なお、図１、図２に示す有機電界発光素子は、発光材料（発光層）を、真空蒸着や溶液または分散液を塗布・乾燥することが可能である。しかし、良好な薄膜にならないものや、明確な電子輸送性を示さないものを用いる場合に、有機電界発光素子の熱耐久性向上、キャリアバランスの向上或いは発光効率の向上を図る目的で、発光層４と背面電極７との間に電子輸送層を設けた層構成である。
【００８１】
電荷輸送性ポリエーテルが含有してなる有機化合物層は、その構造によっては、図１及び図２に示される有機電界発光素子の層構成の場合、正孔輸送層３、電子輸送層５としていずれにも作用することができるし、また、図３及び図４に示される有機電界発光素子の層構成の場合、正孔輸送層３、電荷輸送能を持つ発光層６としていずれも作用することができる。
【００８２】
図１から図４に示される有機電界発光素子の層構成の場合、透明絶縁体基板１は、発光を取り出すため透明なものが好ましく、ガラス、プラスチックフィルム等が用いられる。透明であるということは、可視領域の光の透過率が１０％以上であることを示しており、更に透過率が７５％以上であることが好ましい。透明電極２は、透明絶縁体基板と同様に発光を取り出すため透明であって、かつ正孔の注入を行うため仕事関数の大きなものが良く、仕事関数が４ｅＶ以上のものが好ましい。具体例として、酸化スズインジウム（ＩＴＯ）、酸化スズ（ＮＥＳＡ）、酸化インジウム、酸化亜鉛、酸化インジウム亜鉛等の酸化膜、および蒸着或いはスパッタされた金、白金、パラジウム等が用いられる。電極のシート抵抗は、低いほどが望ましく、数百Ω／□以下が好ましく、さらには１００Ω／□以下がより好ましい。また、透明絶縁体基板同様に、可視領域の光の透過率が１０％以上で、更に透過率が７５％以上であることが好ましい。
【００８３】
図２及び図４に示される有機電界発光素子の層構成の場合、正孔輸送層３は、目的に応じて機能（正孔輸送能）が付与された前記電荷輸送性ポリエーテル単独で形成されていてもよいが、正孔移動度を調節するために電荷輸送性ポリエーテル以外の正孔輸送材料を０．１重量％ないし５０重量％の範囲で混合分散して形成されてもよい。このような正孔輸送材料としては、テトラフェニレンジアミン誘導体、トリフェニルアミン誘導体、カルバゾール誘導体、スチルベン誘導体、アリールヒドラゾン誘導体、ポルフィリン系化合物が挙げられるが、電荷輸送性ポリエーテルとの相溶性が良いことから、テトラフェニレンジアミン誘導体、トリフェニルアミン誘導体が好ましい。なお、前記電荷輸送性ポリエーテルを用いない場合、これら正孔輸送性材料単独で形成されることとなる。
【００８４】
さらに、成膜性の向上、ピンホール防止等のため、適切な樹脂（ポリマー）、添加剤を加えても良い。具体的な樹脂としては、ポリカーボネート樹脂、ポリエステル樹脂、メタクリル樹脂、アクリル樹脂、ポリ塩化ビニル樹脂、セルロース樹脂、ウレタン樹脂、エポキシ樹脂、ポリススチレン樹脂、ポリビニルアセテート樹脂、スチレンブタジエン共重合体、塩化ビニルデン−アクリロニトリル共重合体、塩化ビニル−酢酸ビニル−無水マレイン酸共重合体、シリコン樹脂、ポリ−Ｎ−ビニルカルバゾール樹脂、ポリシラン樹脂、ポリチオフェン、ポリピロール等の導電性樹脂等を用いることができる。また、添加剤としては、公知の酸化防止剤、紫外線吸収剤、可塑剤等を用いることができる。
【００８５】
図１及び図２に示される有機電界発光素子の層構成の場合、発光層４には、固体状態で高い蛍光量子収率を示す化合物が発光材料として用いられる。該発光材料が有機低分子の場合、真空蒸着法もしくは該有機低分子と樹脂を含む溶液または分散液を塗布・乾燥することにより良好な薄膜形成が可能であることが好ましい。用いる樹脂としては、上記正孔輸送層の場合に例示したものが適用できる。また、前記発光材料が高分子からなる場合、それ自身を含む溶液または分散液を塗布・乾燥することにより良好な薄膜形成が可能であることが好ましい。
【００８６】
発光材料が有機低分子の場合の好適な例としては、キレート型有機金属錯体、多核または縮合芳香環化合物、ペリレン誘導体、クマリン誘導体、スチリルアリーレン誘導体、シロール誘導体、オキサゾール誘導体、オキサチアゾール誘導体、オキサジアゾール誘導体等が、高分子の場合、ポリパラフェニレン誘導体、ポリパラフェニレンビニレン誘導体、ポリチオフェン誘導体、ポリアセチレン誘導体等が用いられる。好適な具体例として、下記の化合物（Ｖ−１）〜化合物（Ｖ−１５）が用いられるが、これらに限られるものではない。なお、例示化合物（Ｖ−１３）から（Ｖ−１５）中、ｎおよびｘは１以上の整数を示す。
【００８７】
【化１４】

【００８８】
【化１５】

【００８９】
また、有機電界発光素子の耐久性向上或いは発光効率の向上を目的として、上記の発光材料中にゲスト材料として発光材料と異なる色素化合物をドーピングしてもよい。真空蒸着によって発光層を形成する場合、共蒸着によってドーピングを行い、溶液または分散液を塗布・乾燥することで発光層を形成する場合、溶液または分散液中に混合することでドーピングを行う。発光層中における色素化合物のドーピングの割合としては０．００１重量％〜４０重量％程度、好ましくは０．００１重量％〜１０重量％程度である。このようなドーピングに用いられる色素化合物としては、発光材料との相容性が良く、かつ発光層の良好な薄膜形成を妨げない有機化合物が用いられ、好適にはＤＣＭ誘導体、キナクリドン誘導体、ルブレン誘導体、ポルフィリン等が用いられる。好適な具体例として、下記の化合物（ＶＩ−１）〜（ＶＩ−４）があげられるが、これらに限られるものではない。
【００９０】
【化１６】

【００９１】
図１及び図２に示される有機電界発光素子の層構成の場合、電子輸送層５は、目的に応じて機能（電子輸送能）が付与された前記電荷輸送ポリエーテル単独で形成されてもよいが、発光効率の向上、電気特性をさらに改善する等の目的で、電子移動度を調整するために、電荷輸送ポリエーテル以外の電子輸送材料を０．１重量％から５０重量％の範囲で混合分散して形成されてもよい。このような電子輸送材料として、オキサジアゾール誘導体、ニトロ置換フルオレノン誘導体、ジフェノキノン誘導体、チオピランジオキシド誘導体、フルオレニリデンメタン誘導体等が挙げられる。好適な具体例として、下記の化合物（ＶＩＩ−１）〜（ＶＩＩ−３）があげられるが、これらに限られるものではない。なお、上記正孔輸送層３と同様に適切な樹脂、添加剤を加えて良い。用いる樹脂としては、上記正孔輸送層３の場合に例示したものが適用できる。
【００９２】
【化１７】

【００９３】
図３または図４における有機電界発光素子の層構成の場合、電荷輸送機能を持つ発光層６は目的に応じて機能（正孔輸送能、或いは電子輸送能）が付与された前記電荷輸送性ポリエーテルに対して発光材料を５０重量％以下混合させた有機化合物層であり、発光材料としては前記化合物（Ｖ−１）ないし化合物（Ｖ−１２）が好適に用いられるが、有機電界発光素子に注入される正孔と電子のバランスを調節するために電子輸送材料を０．１重量％〜５０重量％分散させてもよい。このような電子輸送材料としては、前記電荷輸送性ポリエーテルと強い電子相互作用を示さない有機化合物が用いられることが好ましく、好適には下記の化合物（ＶＩＩＩ）が用いられるがこれに限られるものではない。同様に正孔移動度を調節するために電荷輸送性ポリエーテル以外の正孔輸送材料、好ましくはテトラフェニレンジアミン誘導体を適量同時に分散させて用いてもよい。また、正孔輸送層３と同様に適切な樹脂、添加剤を加えても良い。用いる樹脂としては、正孔輸送層３の場合に例示したものが適用できる。また、発光材料と異なる色素化合物をドーピングしてもよい。
【００９４】
【化１８】

【００９５】
図１から図４に示される有機電界発光素子の層構成の場合、背面電極７には、真空蒸着可能で、電子注入を行うため仕事関数の小さな金属、金属酸化物、金属フッ化物等が使用される。金属としてはマグネシウム、アルミニウム、銀、インジウム、リチウム、カルシウムおよびこれらの合金が挙げられる。金属酸化物としては、酸化リチウム、酸化マグネシウム、酸化アルミニウムが挙げられる。また、金属フッ化物としては、フッ化リチウム、フッ化マグネシウム、フッ化ストロンチウム、フッ化カルシウム、フッ化アルミニウムが挙げられる。また、背面電極７上には、さらに素子の水分や酸素による劣化を防ぐために保護層を設けてもよい。具体的な保護層の材料としては、Ｉｎ、Ｓｎ、Ｐｂ、Ａｕ、Ｃｕ、Ａｇ、Ａｌ等の金属、ＭｇＯ、ＳｉＯ_２、ＴｉＯ_２等の金属酸化物、ポリエチレン樹脂、ポリウレア樹脂、ポリイミド樹脂等の樹脂が挙げられる、保護層の形成には、真空蒸着法、スパッタリング法、プラズマ重合法、ＣＶＤ法、コーテング法が適用できる。
【００９６】
これら図１から図４に示される有機電界発光素子は、まず透明電極２の上に各有機電界発光素子の層構成に応じて、正孔輸送層３、発光層４、電子輸送層５及び／又は電荷輸送能を持つ発光層６を形成する。正孔輸送層３、発光層４、電子輸送層５、或いは電荷輸送能を持つ発光層６は、上記各材料を真空蒸着法、もしくは、適切な有機溶媒に溶解或いは分散し、得られた塗布液を用いて前記透明電極上にスピンコーティング法、キャスト法、ディップ法等により形成される。
また、正孔輸送層３、発光層４、電子輸送層５および電荷輸送能を持つ発光層６の膜厚は、各々１０μｍ以下、特に０．００１から５μｍの範囲であることが好ましい。上記各材料（前記電荷輸送性ポリエーテル、発光材料等）の分散状態は分子分散状態でも微結晶などの微粒子状態でも構わない。塗布液を用いた成膜法の場合、分子分散状態とするために分散溶媒は上記各材料の分散性及び溶解性を考慮して選択する必要がある。微粒子状に分散するためには、ボールミル、サンドミル、ペイントシャイカー、アトライター、ホモジナイザー、超音波法等が利用できる。
そして、最後に、電子輸送層或いは電荷輸送能を持つ発光層６の上に背面電極７を真空蒸着法、スパッタリング法等により形成することにより素子が完成される。
【００９７】
【実施例】
以下、本発明を、実施例を挙げてさらに具体的に説明する。だだし、これら各実施例は、本発明を制限するものではない。
【００９８】
（実施例１）
透明絶縁基板上に形成されたＩＴＯ（三容真空社製）を短冊状のフォトマスクを用いてフォトリソグラフィによりパターニングし、さらにエッチング処理することにより短冊状のＩＴＯ電極（幅２ｍｍ）を形成した。次に、このＩＴＯガラス基板を中性洗剤、純水、アセトン（電子工業用、関東化学製）およびイソプロパノール（電子工業用、関東化学製）で超音波を各５分間加えて洗浄した後、スピンコーターで乾燥させた。前記基板に、正孔輸送層として、電荷輸送性ポリエーテル〔例示化合物（６）〕を５重量％ジクロロエタン溶液に調製し、０．１μｍのＰＴＦＥフィルターで濾過した後、ディップ法により厚さ０．０５０μｍの薄膜を形成した。発光材料として前記例示化合物（Ｖ−１）を蒸着して、厚さ０．０６５μｍの発光層を形成した。続いて短冊状の穴が設けられている金属性マスクを用いて、最後にこのマスクを設置してＭｇ−Ａｇ合金を共蒸着により蒸着して、２ｍｍ幅、０．１５μｍ厚の背面電極をＩＴＯ電極と交差するように形成した。形成された有機電界発光素子の有効面積は０．０４ｃｍ^２であった。
【００９９】
（実施例２）
電荷輸送性ポリエーテル〔例示化合物（７）〕１重量部、ポリ（Ｎ−ビニルカルバゾール）４重量部、前記例示化合物（Ｖ−１）を、１０重量％ジクロロエタン溶液を調製し、０．１μｍのＰＴＦＥフィルターで濾過した。この溶液を用いて、実施例１同様にエッチング、洗浄したＩＴＯガラス基板に、電荷輸送能を持つ発光層として、２ｍｍ幅の短冊型ＩＴＯ電極をエッチングにより形成したガラス基板上に、スピンコーター法により膜厚約０．１５μｍの薄膜を形成した。充分乾燥させた後、Ｍｇ−Ａｇ合金を共蒸着により蒸着して、２ｍｍ幅、０．１５μｍ厚の背面電極をＩＴＯ電極と交差するように形成した。形成された有機電界発光素子の有効面積は０．０４ｃｍ^２であった。
【０１００】
（実施例３）
実施例１同様にエッチング、洗浄したＩＴＯガラス基板に、実施例１同様に正孔輸送層として、電荷輸送性ポリエーテル〔例示化合物（１５）〕を厚さ０．０５０μｍを形成した。発光層として前記例示化合物（Ｖ−１）と前記例示化合物（ＶＩ−１）を厚さ０．０６５μｍ、電子輸送層として前記例示化合物（ＶＩＩ−１）を厚さ０．０３０μｍを形成した。続いてＭｇ−Ａｇ合金を共蒸着により蒸着して、２ｍｍ幅、０．１５μｍ厚の背面電極をＩＴＯ電極と交差するように形成した。形成された有機電界発光素子の有効面積は０．０４ｃｍ^２であった。
【０１０１】
（実施例４）
実施例１で用いた例示化合物（６）の代わりに例示化合物（８）を用いた以外は、実施例１と同様にして有機電界発光素子を作製した。
【０１０２】
（実施例５）
実施例２で用いた例示化合物（７）の代わりに例示化合物（２０）を用いた以外は、実施例２と同にして有機電界発光素子を作製した。
【０１０３】
（実施例６）
実施例３で用いた例示化合物（１５）の代わりに例示化合物（３７）を用いた以外は、実施例３と同様にして有機電界発光素子を作製した。
【０１０４】
（実施例７）
実施例３で用いた例示化合物（１５）の代わりに例示化合物（３９）を用いた以外は、実施例３と同様にして有機電界発光素子を作製した。
【０１０５】
（実施例８）
実施例３で用いた例示化合物（１５）の代わりに例示化合物（４７）を用いた以外は、実施例３と同様にして有機電界発光素子を作製した。
【０１０６】
（実施例９）
実施例１に用いた電荷輸送性ポリエーテル〔例示化合物（６）〕１．５重量部％ジクロロエタン溶液を調製し、０．１μｍのＰＴＦＥフィルターで濾過した。この溶液を用いて、実施例１同様にエッチング、洗浄したＩＴＯガラス基板（２ｍｍ幅の短冊型ＩＴＯ電極をエッチングにより形成したガラス基板）上に、正孔輸送層として、スピンコーター法により膜厚約０．１０μｍの薄膜を形成した。発光材料として前記例示化合物（ＩＶ−１）を蒸着して、厚さ０．０５０μｍの発光層を形成した。次に、電子輸送層として、電荷輸送性ポリエーテル〔例示化合物（２８）〕をスピンコーター法により塗布し、厚さ０．０５μｍの薄膜を形成した。充分乾燥させた後、Ｍｇ−Ａｇ合金を共蒸着により蒸着して、２ｍｍ幅、０．１５μｍ厚の背面電極をＩＴＯ電極と交差するように形成した。形成された有機電界発光素子の有効面積は０．０４ｃｍ^２であった。
【０１０７】
（比較例１）
上記実施例１で用いた例示化合物（６）の代わりに下記構造式（ＩＸ）で示される化合物を用いた他は実施例１と同様に素子を作製した。
【０１０８】
【化１９】

【０１０９】
（比較例２）
電荷輸送性ポリマーとしてポリビニルカルバゾール（ＰＶＫ）を２重量部、発光材料として前記例示化合物（Ｖ−１）を０．１重量部、電子輸送材料として前記化合物（ＶＩＩ−１）を１重量部混合し、１０重量％ジクロロエタン溶液を調製し、０．１μｍのＰＴＦＥフィルターで濾過した。この溶液を用いて、２ｍｍ幅の短冊型ＩＴＯ電極をエッチングにより形成したガラス基板上に、ディップ法により塗布して膜厚０．１５μｍのホール輸送層を形成した。十分乾燥させた後、Ｍｇ−Ａｇ合金を共蒸着により蒸着して、２ｍｍ幅、０．１５μｍ厚の背面電極をＩＴＯ電極と交差するように形成した。形成された有機電界発光素子の有効面積は０．０４ｃｍ^２であった。
【０１１０】
（評価）
以上のように作製した有機電界発光素子を、真空中（１３３．３×１０^−３Ｐａ）でＩＴＯ電極側をプラス、Ｍｇ−Ａｇ背面電極をマイナスとして直流電圧を印加し、発光について測定を行い、このときの最高輝度、および発光色を評価した。それらの結果を表２１に示す。また、乾燥窒素中で有機電界発光素子の発光寿命の測定を行った。発光寿命の評価は、初期輝度が５０ｃｄ／ｍ^２となるように電流値を設定し、定電流駆動により輝度が初期値から半減するまでの時間を素子寿命（ｈｏｕｒ）とした。この時の駆動電流密度を素子寿命と共に表２１に示す。
【０１１１】
【表２１】

【０１１２】
これら実施例から明らかなように、熱耐久性、溶剤や樹脂に対する溶解性及び相溶性に優れた電荷輸送性ポリエーテルを用いた本発明の有機電界発光素子は、高輝度、高効率で素子寿命の長く且つピンホール等の不良も少なく、大面積化も容易であることがわかる。
【０１１３】
【発明の効果】
以上、本発明によれば、発光時の熱安定性、保存安定性、溶剤や樹脂に対する溶解性及び相溶性に優れた電荷輸送ポリエーテルを用い、発光強度が大きく、発光効率が高く、素子寿命が長く、且製造が容易な有機電界発光素子を提供することができる。
【図面の簡単な説明】
【図１】本発明の有機電界発光素子の層構成の一例を示した概略構成図である。
【図２】本発明の有機電界発光素子の層構成の一例を示した概略構成図である。
【図３】本発明の有機電界発光素子の層構成の一例を示した概略構成図である。
【図４】本発明の有機電界発光素子の層構成の一例を示した概略構成図である。
【符号の説明】
１　透明絶縁体基板
２　透明電極
３　正孔輸送層
４　発光層
５　電子輸送層
６　電荷輸送能を持つ発光層
７　背面電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an element that converts electric energy into light and emits light, and relates to an organic electroluminescent element (organic EL) that can be suitably used in the fields of display elements, backlights, illumination light sources, exposure apparatuses for electrophotography, signs, signs, and the like. Element).
[0002]
[Prior art]
The electroluminescent element is a self-luminous all-solid-state element, has high visibility and is resistant to impact, and is widely expected to be applied. At present, those using inorganic phosphors are mainly used and widely used. However, since driving voltage of 200 V or more is required, running costs are high and luminance is insufficient. Have. On the other hand, research on an electroluminescent device using an organic compound was first started using a single crystal such as anthracene, but the film thickness was as thick as about 1 mm, and a driving voltage of 100 V or more was required. For this reason, attempts have been made to reduce the thickness by a vapor deposition method (Thin Solid Films, 94, 171 (1982)). In the light emission of these elements, electrons are injected from one of the electrodes and holes are injected from the other electrode, so that the luminescent material in the element is excited to a high energy level, and the excited luminescent material is emitted from the base. It is a phenomenon that emits extra energy as light when returning to the state. However, the driving voltage is still as high as 30 V, the density of electron and hole carriers in the film is low, and the probability of photon generation due to the recombination of carriers is low, so that sufficient luminance cannot be obtained. Did not.
[0003]
However, in 1997, Tang et al. Disclosed a function-separated organic thin-film in which an extremely thin thin film of a hole-transporting organic low-molecular compound and a fluorescent organic low-molecular compound having an electron-transporting ability were sequentially laminated on a transparent substrate by vacuum evaporation. 1000 cd / m at low voltage of about 10 V ² A device capable of obtaining the above high luminance has been reported (Appl. Phys. Lett., 51, 913 (1987), JP-A-59-194393), and since then, research and development of organic electroluminescent devices have been actively conducted. Has been done. These stacked electroluminescent devices have a structure in which an organic luminous body and a charge-transporting organic substance (charge-transporting material) are laminated on an electrode. Holes and electrons move through the charge-transporting material, and are regenerated. It emits light when combined. Organic dyes that emit fluorescence, such as 8-quinolinol aluminum complex and coumarin compounds, are used as the organic luminous body. Examples of the charge transport material include diamino compounds such as N, N-di (m-tolyl) N, N′-diphenylbenzidine and 1,1-bis [N, N-di (p-tolyl) aminophenyl] cyclohexane. And 4- (N, N-diphenyl) aminobenzaldehyde-N, N-diphenylhydrazone compound.
[0004]
However, although the organic electroluminescent device has high light emitting characteristics, it has a problem in thermal stability and storage stability during light emission. A layer formed of an organic material of an electroluminescent element is extremely thin, from several tens to several hundreds of nanometers, and a voltage applied per unit thickness is extremely high, and is several mA / cm. ² It generates a large amount of Joule heat because it is driven at a high current density. For this reason, the hole-transporting low-molecular compound or fluorescent organic low-molecular compound formed in an amorphous glass state by vapor deposition gradually crystallizes and finally melts, resulting in a phenomenon in which luminance decreases and dielectric breakdown occurs. This is often seen, and as a result, there is a problem that the life of the element is shortened. In addition, there has been a problem that the element is deteriorated due to a change over time due to long-term use or an atmospheric gas containing oxygen or moisture.
[0005]
Then, in order to solve the problem regarding the thermal stability of the electroluminescent device, a starburst amine which can obtain a stable amorphous glass state as a hole transport material (Preliminary proceedings of the 40th Symposium on Applied Physics) 30a-SZK- 14 (1993)) or a polymer in which triphenylamine is introduced into the side chain of polyphosphazene (the 42nd Polymer Symposium Preprints, 20J21 (1993)). I have. However, these alone do not satisfy the hole injecting property from the anode or the hole injecting property into the light emitting layer because there is an energy barrier due to the ionization potential of the hole transporting material. In addition, in the case of the former starburst amine, purification is difficult due to low solubility, and it is difficult to increase the purity.In the case of the latter polymer, a high current density is not obtained and sufficient luminance is obtained. There are also problems such as not having.
[0006]
On the other hand, in order to solve these problems, research and development of an electroluminescent element having a single-layer structure have been advanced, and a conductive polymer such as poly (p-phenylenevinylene) has been used (Nature, 357, 477 (1992)). )), A device in which an electron transporting material and a fluorescent dye are mixed in a hole transporting polyvinyl carbazole (Preliminary Collection of the 38th Joint Lecture Meeting on Applied Physics, 31p-G-12 (1991)). However, the luminance, the luminous efficiency, and the like are still lower than those of the stacked electric field generating device using an organic low-molecular compound.
[0007]
Further, it is reported that a coating method is preferable in terms of manufacturing simplicity, workability, large area, cost, etc., and that an element can be obtained by a casting method (50th Japan Society of Applied Physics). Proceedings of Academic Lectures, 29p-ZP-5 (1989)), Proceedings of the 51st JSAP, 28a-PB-7 (1990)). However, since the charge transport material has poor solubility and compatibility with solvents and resins, it tends to crystallize and has defects in production or characteristics.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems in the conventional technology and to achieve the following objects. That is, an object of the present invention is to use a charge transporting polyether having excellent thermal stability during storage, storage stability, solubility and compatibility with a solvent or a resin, high emission intensity, high emission efficiency, and device life. It is an object of the present invention to provide an organic electroluminescent device which is long and easy to manufacture.
[0009]
[Means for Solving the Problems]
As a result of intensive studies on the charge transport polymer to achieve the above object, a charge transport polymer containing as a partial structure at least one selected from the structures represented by the following general formulas (I-1) and (I-2) has been obtained. The present inventors have found that they have charge injection characteristics, charge mobility, thin film forming ability, and light emission characteristics suitable for an organic electroluminescent device, and have completed the present invention.
[0010]
That is, the organic electroluminescent device of the present invention is constituted by one or a plurality of organic compound layers sandwiched between a pair of electrodes consisting of an anode and a cathode, at least one of which is transparent or translucent, At least one of the organic compound layers is a charge-transporting polyether (hereinafter, referred to as a “charge-transporting polyether”) comprising a repeating unit containing at least one selected from structures represented by the following general formulas (I-1) and (I-2) as a partial structure. (Hereinafter sometimes simply referred to as "charge transporting polyether").
[0011]
Embedded image

[0012]
(In the formulas (I-1) and (I-2), X is a substituted or unsubstituted divalent benzene group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings.) Represents a substituted or unsubstituted monovalent condensed aromatic hydrocarbon having 2 to 10 aromatic rings or a substituted or unsubstituted monovalent aromatic heterocyclic ring, wherein T is a divalent straight-chain having 1 to 6 carbon atoms. Represents a chain hydrocarbon group or a divalent branched hydrocarbon group having 2 to 10 carbon atoms, m represents an integer of 0 to 3, k represents 0 or 1, and Ar represents the following general formula (II) -1) or a substituent represented by (II-2).
[0013]
Embedded image

[0014]
(In the general formulas (II-1) and (II-2), Ar ₁ Is a substituted or unsubstituted monovalent benzene ring, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatics, a substituted or unsubstituted monovalent aromatic hydrocarbon having 2 to 10 aromatic rings. Represents a condensed polycyclic aromatic hydrocarbon, a substituted or unsubstituted monovalent aromatic heterocycle, or a monovalent substituent containing at least one kind of aromatic heterocycle. Ar2, Ar ₃ And Ar ₄ Are each independently a substituted or unsubstituted divalent benzene ring, a substituted or unsubstituted divalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic groups, a substituted or unsubstituted aromatic ring number of 2 to 10 Represents a divalent fused polycyclic aromatic hydrocarbon, a substituted or unsubstituted divalent aromatic heterocycle, or a substituted or divalent substituent containing at least one kind of aromatic heterocycle. R ₁ , R ₂ , R ₃ And R ₄ Each independently represents a hydrogen atom, an alkyl group, a cyano group, a halogen group, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group; ₁ , R ₂ , R ₃ And R ₄ May be the same or different. n represents an integer of 0 to 10. )
[0015]
As the charge transporting polyether, a polyether represented by the following general formula (III) can be preferably mentioned.
[0016]
Embedded image

[0017]
(In the general formula (III), A represents at least one selected from the structures represented by the general formulas (I-1) and (I-2). R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted group. Represents an aryl group or a substituted or unsubstituted aralkyl group. P represents an integer of 5 to 5,000.)
[0018]
The organic compound layer constituting the organic electroluminescent device of the present invention is broadly classified into a single-layer structure composed of only a light-emitting layer having a charge transport function, or a mutual structure including at least a light-emitting layer or a light-emitting layer having charge transport. It has a function-separated multi-layer structure composed of a plurality of layers having different functions. Examples of the function-separated type multi-layer structure include (1) a light-emitting layer and an electron transport layer (hereinafter, may be abbreviated as “layer structure (1)”), (2) a hole transport layer, a light-emitting layer, and an electron. Transport layer (hereinafter sometimes abbreviated as “layer configuration (2)”), (3) hole transport layer and light-emitting layer having charge transport ability (hereinafter sometimes abbreviated as “layer configuration (3)”) Is mentioned. In this configuration, the hole injection layer is included in the hole transport layer, and the electron injection layer is included in the electron transport layer. Further, the layer configuration is not limited to this.
[0019]
When the organic compound layer is composed of only the light emitting layer having the charge transport function, the light emitting layer having the charge transport function has the structure represented by the general formulas (I-1) and (I-2). A charge-transporting polyether comprising a repeating unit containing at least one selected from the group consisting of:
On the other hand, when the organic compound layer is composed of a plurality of function-separated layers, in the layer configuration (1), at least one of the light emitting layer and the electron transport layer contains the charge transporting polyether, In the constitution (2), the charge transporting polyether is contained in at least one of the hole transport layer and the electron transport layer, and in the layer constitution (3), the hole transport layer and the light emitting layer having the charge transport function are provided. At least one of them contains the charge transporting polyether.
The organic compound layer may further include a charge transporting material (a hole transporting material, an electron transporting material) other than the charge transporting polyether.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
The organic electroluminescent device of the present invention comprises one or a plurality of organic compound layers sandwiched between a pair of electrodes consisting of an anode and a cathode, at least one of which is transparent or translucent, and at least one of the organic compound layers Contains at least one kind of charge transporting polyether comprising a repeating unit containing at least one kind selected from the structures represented by the following general formulas (I-1) and (I-2) as a partial structure.
[0021]
This charge transporting polyether is excellent in thermal stability at the time of light emission, solubility and compatibility with a solvent or resin, and the organic electroluminescent device of the present invention contains the charge transporting polyether. Since the organic compound layer includes the organic compound layer, the emission intensity is high, the emission efficiency is high, the device life is long, and the production is easy.
[0022]
Embedded image

[0023]
In the general formulas (I-1) and (I-2), X represents a substituted or unsubstituted divalent benzene group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings, Represents a substituted or unsubstituted monovalent fused aromatic hydrocarbon having 2 to 10 aromatic rings, or a substituted or unsubstituted monovalent aromatic heterocyclic ring.
[0024]
In the general formulas (I-1) and (I-2), Ar represents a substituent represented by the general formula (II-1) or (II-2).
[0025]
Embedded image

[0026]
In the general formulas (II-1) and (II-2), Ar ₁ Is a substituted or unsubstituted monovalent benzene ring, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatics, a substituted or unsubstituted monovalent monovalent aromatic hydrocarbon having 2 to 10 aromatic rings. Represents a condensed polycyclic aromatic hydrocarbon, a substituted or unsubstituted monovalent aromatic heterocycle, or a monovalent substituent containing at least one kind of aromatic heterocycle. Ar2, Ar ₃ And Ar ₄ Are each independently a substituted or unsubstituted divalent benzene ring, a substituted or unsubstituted divalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic atoms, a substituted or unsubstituted aromatic ring number of 2 to 10 Represents a divalent fused polycyclic aromatic hydrocarbon, a substituted or unsubstituted divalent aromatic heterocycle, or a substituted or divalent substituent containing at least one kind of aromatic heterocycle. R ₁ , R ₂ , R ₃ And R ₄ Each independently represents a hydrogen atom, an alkyl group, a cyano group, a halogen group, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group; ₁ , R ₂ , R ₃ And R ₄ May be the same or different. n represents an integer of 0 to 10.
[0027]
X, Ar ₁ , Ar ₂ , Ar ₃ And Ar ₄ The monovalent or divalent polynuclear aromatic hydrocarbon and the condensed polycyclic aromatic hydrocarbon selected as the structure representing are not particularly limited, and may have any structure.
[0028]
Here, in the present invention, the polynuclear aromatic hydrocarbon and the condensed aromatic hydrocarbon specifically mean those defined below.
That is, the “polynuclear aromatic hydrocarbon” refers to a hydrocarbon in which two or more aromatic rings composed of carbon and hydrogen exist, and the rings are bonded to each other by a carbon-carbon bond. Specific examples include biphenyl and terphenyl. The term "condensed aromatic hydrocarbon" refers to a hydrocarbon in which two or more aromatic rings composed of carbon and hydrogen exist, and the rings share a pair of carbon atoms. Specific examples include naphthalene, anthracene, phenanthrene, and fluorene. In the heterocyclic ring, Nr = 5 and / or 6 is preferably used as a primitive (Nr) constituting the ring skeleton. The type and number of atoms (heteroatoms) other than carbon atoms constituting the ring skeleton are not particularly limited, but, for example, a sulfur atom, a nitrogen atom, an oxygen atom and the like are preferably used. More than one and / or two or more different atoms may be included. In particular, as the heterocycle having a 5-membered ring structure, thiophene, pyrrole, and furan, or a heterocycle in which the 3- and 4-position carbons of the compound are replaced with nitrogen are preferably used. As the heterocycle having a 6-membered ring structure, Pyridine is preferably used.
[0029]
X, Ar ₁ , Ar ₂ , Ar ₃ And Ar ₄ Examples of the substituent that can be substituted with the structure represented by include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a substituted amino group, and a halogen atom. The alkyl group preferably has 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. The alkoxyl group preferably has 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group. The aryl group preferably has 6 to 20 carbon atoms, and examples thereof include a phenyl group and a toluyl group. The aralkyl group preferably has 7 to 20 carbon atoms, such as a benzyl group and a phenethyl group. Is mentioned. Examples of the substituent of the substituted amino group include an alkyl group, an aryl group, and an aralkyl group, and specific examples are as described above.
[0030]
X, Ar ₁ , Ar ₂ , Ar ₃ And Ar ₄ Specific examples of the structure represented by preferably include groups selected from the following formulas (1) to (13). In the case of a monovalent group, a structure in which any one of the hydrogen groups in the following specific examples is eliminated, and in a case of a divalent group, a structure in which any two of the hydrogen groups of the following specific examples are eliminated. .
[0031]
Embedded image

[0032]
In the formulas (1) to (13), R ₅ To R ₂₀ Represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, or a halogen atom. R ₇ Represents a hydrogen atom, an alkyl group, or a cyano group. a represents 0 or 1, and b represents an integer of 0 to 10. V represents a group selected from the following formulas (14) to (34).
[0033]
Embedded image

[0034]
In the formulas (14) to (33), R ₂₁ ~ R ₂₃ Represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, or a halogen atom. R ₇ Represents a hydrogen atom, an alkyl group, or a cyano group. c means an integer of 0 to 10.
[0035]
In the general formulas (I-1) and (I-2), T represents a divalent linear hydrocarbon group having 1 to 6 carbon atoms or a divalent branched hydrocarbon group having 2 to 10 carbon atoms. And is preferably selected from a divalent linear hydrocarbon group having 2 to 6 carbon atoms and a divalent branched hydrocarbon group having 3 to 7 carbon atoms. The specific structure is shown below.
[0036]
Embedded image

[0037]
Hereinafter, specific examples of the structures represented by formulas (I-1) to (I-2) are shown, but the present invention is not limited thereto. Structure numbers 1 to 124 are specific examples of the structure represented by the general formula (I-1), and structure numbers 125 to 213 are specific examples of the structure represented by the general formula (I-2).
[0038]
[Table 1]

[0039]
[Table 2]

[0040]
[Table 3]

[0041]
[Table 4]

[0042]
[Table 5]

[0043]
[Table 6]

[0044]
[Table 7]

[0045]
[Table 8]

[0046]
[Table 9]

[0047]
[Table 10]

[0048]
[Table 11]

[0049]
[Table 12]

[0050]
[Table 13]

[0051]
[Table 14]

[0052]
[Table 15]

[0053]
[Table 16]

[0054]
[Table 17]

[0055]
[Table 18]

[0056]
Examples of the charge transporting polyether comprising a repeating unit having at least one selected from the structures represented by formulas (I-1) and (I-2) as a partial structure include those represented by the following formula (III). It is preferably used.
[0057]
Embedded image

[0058]
In the general formula (III), A represents at least one selected from the structures represented by the general formulas (I-1) and (I-2), and two or more types of the structures A are contained in one polymer. It may be.
[0059]
In the general formula (III), R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. The alkyl group preferably has 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and an isopropyl group. The aryl group preferably has 6 to 20 carbon atoms, and examples thereof include a phenyl group and a toluyl group. The aralkyl group preferably has 7 to 20 carbon atoms, such as a benzyl group and a phenethyl group. Is mentioned. Examples of the substituent of the substituted aryl group and the substituted aralkyl group include a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, and a halogen atom. m represents an integer of 1 to 5.
[0060]
The weight-average molecular weight Mw of the charge transporting polyether composed of a repeating unit with at least one selected from the structures represented by formulas (I-1) and (I-2) as a partial structure is in the range of 5,000 to 300,000. Are preferred.
[0061]
Hereinafter, specific examples of the above-described charge transporting polyether represented by the general formula (III) are shown, but the present invention is not limited to these specific examples. In addition, the number in the column of the monomer in the table corresponds to the structure number which is a specific example of the structure represented by the general formulas (I-1) and (I-2). Further, m means m in the general formulas (I-1) and (I-2). Hereinafter, specific examples (compounds) assigned with respective numbers, for example, specific examples assigned with a number of 15 are referred to as exemplary compounds (15).
[0062]
[Table 19]

[0063]
[Table 20]

[0064]
The charge-transporting polyether comprising a repeating unit having at least one selected from the structures represented by the general formulas (I-1) and (I-2) as a partial structure includes, for example, the following general formulas (IV-1) and (IV-1) The compound can be easily produced by condensing the charge transporting compound having a hydroxyl group represented by IV-2) between molecules. Here, Ar, X, T, m, and k in the following general formulas (IV-1) and (IV-2) represent Ar, X, T, and Synonymous with m and k.
[0065]
Embedded image

[0066]
Specifically, the charge transporting polyether can be synthesized, for example, as follows.
1) The charge transporting polyether is a charge transporting compound having two hydroxyalkyl groups of the above formulas (IV-1) and (IV-2) (hereinafter abbreviated as charge transporting monomer (IV)). ) Can be synthesized by a method of performing thermal dehydration condensation. In this case, it is desirable that the charge transporting monomer (IV) is heated and melted without a solvent, and the reaction is performed under reduced pressure in order to promote a polymerization reaction by elimination of water. When a solvent is used, a solvent azeotropic with water, for example, trichloroethane, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene or the like is effective for removing water, and a charge transporting monomer ( IV) It is used in the range of 1 to 100 equivalents, preferably 2 to 50 equivalents to 1 equivalent. The reaction temperature can be arbitrarily set, but the reaction is preferably performed at the boiling point of the solvent in order to remove water generated during the polymerization. When the polymerization does not proceed, the solvent may be removed from the reaction system, and the mixture may be heated and stirred in a viscous state.
[0067]
2) The charge transporting polyether can also be synthesized by a dehydration condensation method using a protonic acid such as p-toluenesulfonic acid, hydrochloric acid, sulfuric acid, and trifluoroacetic acid, or a Lewis acid such as zinc chloride as an acid catalyst. it can. In this case, the acid catalyst is used in an amount of 1 to 1/10000 to 1/10 equivalent, preferably 1/1000 to 1/50 equivalent, relative to 1 equivalent of the charge transporting monomer (IV). In order to remove water generated during the polymerization, it is preferable to use a solvent which can be azeotropic with water. As the solvent, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene and the like are effective, and 1 to 100 equivalents, preferably 2 to 50 equivalents, per equivalent of the charge transporting monomer (IV). Used. The reaction temperature can be arbitrarily set, but the reaction is preferably performed at the boiling point of the solvent in order to remove water generated during the polymerization.
[0068]
3) The charge transporting polyether includes alkyl isocyanate such as cyclohexyl isocyanate, alkyl isocyanate such as cyclohexyl cyanide, and cyanide such as p-tolyl cyanate and 2,2-bis (4-cyanatophenyl) propane. It can also be synthesized by a method using a condensing agent such as an acid ester, dichlorohexylcarbodiimide (DCC), and trichloroacetonitrile. In this case, the condensing agent is used in a range of 1/2 to 10 equivalents, preferably 1 to 3 equivalents, relative to 1 equivalent of the charge transporting monomer (IV). As the solvent, toluene, chlorobenzene, dichlorobenzene, 1-chloronaphthalene and the like are effective, and are used in the range of 1 to 100 equivalents, preferably 2 to 50 equivalents, per 1 equivalent of the charge transporting monomer (IV). The reaction temperature can be arbitrarily set, but the reaction is preferably carried out from room temperature to the boiling point of the solvent.
[0069]
Of the above synthesis methods 1), 2) and 3), synthesis method 1) or 3) is preferable because isomerization and side reactions hardly occur. In particular, the synthesis method 3) is more preferable because the reaction conditions are milder.
After the completion of the reaction, if no solvent is used, the solvent is dissolved in a soluble solvent. When a solvent is used, alcohols such as methanol and ethanol, and a charge-transporting polymer such as acetone are dripped into a poor solvent in which the charge-transporting polymer is difficult to dissolve, and the charge-transporting polymer is precipitated. After being separated, it is sufficiently washed with water or an organic solvent and dried. Further, if necessary, the reprecipitation treatment of dissolving in a suitable organic solvent, dropping it into a poor solvent, and precipitating the charge transporting polymer may be repeated. In the case of the reprecipitation treatment, it is preferable to carry out the stirring with a mechanical stirrer or the like while stirring efficiently. The solvent for dissolving the charge transporting polymer in the reprecipitation treatment is used in the range of 1 to 100 equivalents, preferably 2 to 50 equivalents, per 1 equivalent of the charge transporting polymer. The poor solvent is used in an amount of 1 to 1000 equivalents, preferably 10 to 500 equivalents, per equivalent of the charge transporting polymer. Further, in the above reaction, a copolymer can be synthesized by using two or more, preferably 2 to 5, and more preferably 2 to 3 charge transporting monomers. By copolymerizing different kinds of charge transporting monomers, electrical properties, film formability, solubility and fluorescence properties can be controlled.
[0070]
If the degree of polymerization of the charge transporting polyether is too low, the film formability is poor, and a strong film is hardly obtained. On the other hand, if the degree of polymerization is too high, the solubility in a solvent becomes low and the processability deteriorates. , Preferably in the range of 10 to 3000, more preferably 15 to 1000.
[0071]
The terminal group of the charge transporting polyether may be a hydroxyl group, that is, the terminal group R may be a hydrogen atom as in the case of the charge transporting monomer, but may affect the polymer properties such as solubility, film formability, and mobility. Can modify the terminal group R to control the physical properties. For example, the terminal hydroxyl group can be alkyl etherified with an alkyl sulfate, an alkyl iodide, or the like. Specific reagents can be arbitrarily selected from dimethyl sulfate, diethyl sulfate, methyl iodide, ethyl iodide and the like, and are used in an amount of 1 to 3 equivalents, preferably 1 to 2 equivalents to the terminal hydroxyl group. . At this time, a base catalyst can be used, but the base catalyst can be arbitrarily selected from sodium hydroxide, potassium hydroxide, sodium hydride, sodium metal, and the like, and is preferably up to 3 equivalents to the terminal hydroxyl group, preferably. Is used in the range of 1 to 2 equivalents. The reaction can be carried out at a temperature from 0 ° C. to the boiling point of the solvent used. The solvent used in this case is selected from inert solvents such as benzene, toluene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone. However, a single solvent or a mixture of two or three solvents can be used.
[0072]
Further, depending on the reaction, a quaternary ammonium salt such as tetra-n-butylammonium iodide can be used as a phase transfer catalyst. Further, the terminal hydroxyl group can be converted to an acyl group by acylating the terminal hydroxyl group with an acid halide. The acid halide is not particularly limited. -Toluoyl chloride, m-toluoyl chloride, p-toluoyl chloride and the like, and they are used in an amount of 1 to 3 equivalents, preferably 1 to 2 equivalents to the terminal hydroxyl group. At that time, a base catalyst can be used, but the base catalyst can be arbitrarily selected from pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and the like, and is 1 to 3 equivalents, preferably 1 to 2 equivalents to the acid chloride. Use within the range. Solvents used at that time include benzene, toluene, methyl chloride, tetrahydrofuran, methyl ethyl ketone and the like. The reaction can be carried out from 0 ° C. to the boiling point of the solvent. Preferably, it is carried out in the range of 0 ° C to 30 ° C. Furthermore, acylation can also be performed using an acid anhydride such as acetic anhydride. When a solvent is used, specifically, an inert solvent such as benzene, toluene, and chlorobenzene can be used. The reaction can be carried out from 0 ° C. to the boiling point of the solvent. Preferably, the temperature may be from 40 ° C. to the boiling point of the solvent.
[0073]
In addition, a urethane residue (-CONH-R ') can be introduced into the terminal using monoisocyanate. Specific examples of monoisocyanates include benzyl isocyanate, n-butyl isocyanate, t-butyl isocyanate, cyclohexyl isocyanate, 2,6-dimethyl isocyanate, ethyl isocyanate, and isopropyl isocyanate. 2-methoxyphenyl isocyanate, 4-methoxyphenyl isocyanate, n-octadecyl isocyanate, phenyl isocyanate, i-propyl isocyanate, m-tolyl isocyanate, p-tolyl isocyanate, It can be arbitrarily selected from 1-naphthyl isocyanate and the like, and is used in an amount of 1 to 3 equivalents, preferably 1 to 2 equivalents to the terminal hydroxyl group. Examples of the solvent used at that time include benzene, toluene, chlorobenzene, dichlorobenzene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like. Can be. The reaction temperature can be from 0 ° C. to the boiling point of the solvent used. If the reaction does not proceed easily, use a metal compound such as dibutyltin (II) dilaurate, tin (II) octylate, or lead naphthenate, or a tertiary amine such as triethylamine, trimethylamine, pyridine or dimethylaminopyridine as a catalyst. You can also.
[0074]
Next, the layer structure of the organic electroluminescent device of the present invention will be described in detail.
The organic electroluminescent device of the present invention comprises a pair of electrodes, at least one of which is transparent or translucent, and one or more organic compound layers including a light emitting layer sandwiched between the electrodes. At least one layer contains the charge transporting polyether.
[0075]
In the organic electroluminescent device of the present invention, when the organic compound layer is a single layer, the organic compound means a light emitting layer having a charge transporting ability, and the light emitting layer contains the charge transporting polyether.
On the other hand, when the organic compound layer has a plurality of layers (that is, when each layer has a function-separated type having different functions), at least one layer includes a light-emitting layer or a light-emitting layer having a charge transporting ability. In this case, the layer structure composed of the light emitting layer or the light emitting layer having the charge transporting ability and other layers includes a layer structure (1) composed of a light emitting layer and an electron transport layer, a hole transport layer, a light emitting layer, A layer configuration (2) composed of an electron transport layer; and a layer configuration (3) composed of a hole transport layer and a light-emitting layer having a charge transport ability. The light emission of these layer configurations (1) to (3) is exemplified. The layers other than the layer and the light-emitting layer having a charge transporting function have a function as a charge transporting layer. In this configuration, the hole injection layer is included in the hole transport layer, and the electron injection layer is included in the electron transport layer.
[0076]
In the layer configuration (1), at least one of the light emitting layer and the electron transport layer contains the charge transporting polyether. In the layer configuration (2), the charge transporting polyether is included in at least one of the hole transport layer and the electron transport layer. A charge transporting polyether is contained, and in the layer configuration (3), at least one of the hole transporting layer and the light emitting layer having a charge transporting ability contains the charge transporting polyether.
[0077]
Further, the light-emitting layer, the hole transport layer, and the electron transport layer having the charge transport ability may further include a charge transport compound (a hole transport material, an electron transport material) other than the charge transport polyether. Details will be described later.
[0078]
Hereinafter, the present invention will be described in more detail with reference to the drawings, but is not limited thereto.
FIGS. 1 to 4 are schematic cross-sectional views for explaining the layer structure of the organic electroluminescent element of the present invention. In FIGS. 1, 2 and 4, the case where a plurality of organic compound layers are used is shown. FIG. 3 shows an example in which there is one organic compound layer. Note that, in FIGS. 1 to 4, components having similar functions are denoted by the same reference numerals and described.
[0079]
The organic electroluminescent device shown in FIG. 1 is obtained by sequentially laminating a transparent electrode 2, a light emitting layer 4, an electron transport layer 5, and a back electrode 7 on a transparent insulator substrate 1. The organic electroluminescent device shown in FIG. 2 is formed by sequentially laminating a transparent electrode 2, a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and a back electrode 7 on a transparent insulator substrate 1. The organic electroluminescent device shown in FIG. 3 is formed by sequentially laminating a transparent electrode 2, a light emitting layer 6 having a charge transporting ability, and a back electrode 7 on a transparent insulator substrate 1. The organic electroluminescent device shown in FIG. 4 is formed by sequentially laminating a transparent electrode 2, a hole transport layer 3, a light emitting layer 6 having charge transport ability, and a back electrode 7 on a transparent insulator substrate 1. Hereinafter, each will be described in detail.
[0080]
The organic electroluminescent device shown in FIGS. 1 and 2 can be formed by applying a vacuum deposition, a solution or a dispersion to a light emitting material (light emitting layer) and drying the light emitting material (light emitting layer). However, when a thin film that does not become a good thin film or one that does not show a clear electron transporting property is used, the light emitting layer is used for the purpose of improving the thermal durability of the organic electroluminescent element, improving the carrier balance or improving the luminous efficiency. This is a layer configuration in which an electron transport layer is provided between the rear electrode 4 and the back electrode 7.
[0081]
Depending on the structure of the organic compound layer containing the charge transporting polyether, the hole transport layer 3 or the electron transport layer 5 may be used as the hole transport layer 3 or the electron transport layer 5 in the case of the layer structure of the organic electroluminescent device shown in FIGS. In the case of the layer structure of the organic electroluminescent device shown in FIGS. 3 and 4, both can function as the hole transport layer 3 and the light emitting layer 6 having the charge transport ability. it can.
[0082]
In the case of the layer structure of the organic electroluminescent device shown in FIGS. 1 to 4, the transparent insulator substrate 1 is preferably transparent to take out light emission, and glass, a plastic film or the like is used. Being transparent indicates that the transmittance of light in the visible region is 10% or more, and more preferably 75% or more. Like the transparent insulator substrate, the transparent electrode 2 is preferably transparent for extracting light emission and has a large work function for injecting holes, and preferably has a work function of 4 eV or more. As a specific example, an oxide film of indium tin oxide (ITO), tin oxide (NESA), indium oxide, zinc oxide, indium zinc oxide, or the like, and gold, platinum, palladium, or the like that is deposited or sputtered are used. The sheet resistance of the electrode is preferably as low as possible, preferably several hundred Ω / □ or less, and more preferably 100 Ω / □ or less. Further, as in the case of the transparent insulator substrate, the transmittance of light in the visible region is preferably 10% or more, and more preferably 75% or more.
[0083]
In the case of the layer structure of the organic electroluminescent device shown in FIGS. 2 and 4, the hole transport layer 3 is formed of the charge transporting polyether alone having a function (hole transporting ability) according to the purpose. However, in order to adjust the hole mobility, a hole transport material other than the charge transporting polyether may be mixed and dispersed in the range of 0.1% by weight to 50% by weight. Examples of such a hole transporting material include a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an arylhydrazone derivative, and a porphyrin compound, which have good compatibility with the charge transporting polyether. Thus, a tetraphenylenediamine derivative and a triphenylamine derivative are preferred. When the charge transporting polyether is not used, the charge transporting polyether is used alone.
[0084]
Further, appropriate resins (polymers) and additives may be added to improve film forming properties and prevent pinholes. Specific resins include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, cellulose resin, urethane resin, epoxy resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, and vinyl chloride. Conductive resins such as acrylonitrile copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, poly-N-vinylcarbazole resin, polysilane resin, polythiophene, and polypyrrole can be used. As the additives, known antioxidants, ultraviolet absorbers, plasticizers and the like can be used.
[0085]
In the case of the layer configuration of the organic electroluminescent device shown in FIGS. 1 and 2, a compound exhibiting a high fluorescence quantum yield in a solid state is used for the light emitting layer 4 as a light emitting material. When the light-emitting material is a low-molecular organic compound, it is preferable that a good thin film can be formed by vacuum evaporation or by applying and drying a solution or dispersion containing the low-molecular organic compound and a resin. As the resin to be used, those exemplified for the above-described hole transport layer can be applied. When the light emitting material is composed of a polymer, it is preferable that a good thin film can be formed by applying and drying a solution or a dispersion containing the light emitting material itself.
[0086]
Preferable examples of the case where the light-emitting material is a low-molecular organic compound include chelating organometallic complexes, polynuclear or condensed aromatic ring compounds, perylene derivatives, coumarin derivatives, styrylarylene derivatives, silole derivatives, oxazole derivatives, oxathiazole derivatives, and oxadiazole derivatives. When the azole derivative or the like is a polymer, a polyparaphenylene derivative, a polyparaphenylenevinylene derivative, a polythiophene derivative, a polyacetylene derivative, or the like is used. As preferred specific examples, the following compounds (V-1) to (V-15) are used, but the invention is not limited thereto. Note that, in the exemplified compounds (V-13) to (V-15), n and x each represent an integer of 1 or more.
[0087]
Embedded image

[0088]
Embedded image

[0089]
Further, for the purpose of improving the durability or luminous efficiency of the organic electroluminescent element, the above luminescent material may be doped with a dye compound different from the luminescent material as a guest material. When the light emitting layer is formed by vacuum deposition, doping is performed by co-evaporation, and when the light emitting layer is formed by applying and drying a solution or a dispersion, doping is performed by mixing the solution or the dispersion with the solution or the dispersion. The doping ratio of the dye compound in the light emitting layer is about 0.001 to 40% by weight, preferably about 0.001 to 10% by weight. As the dye compound used for such doping, an organic compound having good compatibility with the light emitting material and not hindering formation of a good thin film of the light emitting layer is used. Preferably, a DCM derivative, a quinacridone derivative, a rubrene derivative is used. , Porphyrin and the like are used. Preferred specific examples include, but are not limited to, the following compounds (VI-1) to (VI-4).
[0090]
Embedded image

[0091]
In the case of the layer configuration of the organic electroluminescent device shown in FIGS. 1 and 2, the electron transporting layer 5 may be formed of the charge transporting polyether alone having a function (electron transporting ability) according to the purpose. However, in order to improve the luminous efficiency and to further improve the electrical characteristics, an electron transport material other than the charge transport polyether is mixed in a range of 0.1% by weight to 50% by weight in order to adjust the electron mobility. It may be formed in a dispersed manner. Examples of such an electron transporting material include an oxadiazole derivative, a nitro-substituted fluorenone derivative, a diphenoquinone derivative, a thiopyrandioxide derivative, and a fluorenylidenemethane derivative. Preferred specific examples include, but are not limited to, the following compounds (VII-1) to (VII-3). Note that, similarly to the hole transport layer 3, an appropriate resin and an additive may be added. As the resin to be used, those exemplified in the case of the hole transport layer 3 can be applied.
[0092]
Embedded image

[0093]
In the case of the layer structure of the organic electroluminescent device shown in FIG. 3 or FIG. 4, the light-emitting layer 6 having the charge transport function has the function (hole transport ability or electron transport ability) according to the purpose. This is an organic compound layer in which a light emitting material is mixed in an amount of 50% by weight or less with respect to ether. As the light emitting material, the compounds (V-1) to (V-12) are preferably used. The electron transporting material may be dispersed in an amount of 0.1% by weight to 50% by weight to adjust the balance between the injected holes and the electrons. As such an electron transporting material, an organic compound that does not show strong electron interaction with the charge transporting polyether is preferably used, and the following compound (VIII) is preferably used, but is not limited thereto. is not. Similarly, in order to adjust the hole mobility, a hole transporting material other than the charge transporting polyether, preferably a tetraphenylenediamine derivative, may be used by being simultaneously dispersed in an appropriate amount. Further, as in the case of the hole transport layer 3, a suitable resin and an additive may be added. As the resin to be used, those exemplified for the hole transport layer 3 can be applied. Further, a dye compound different from the light emitting material may be doped.
[0094]
Embedded image

[0095]
In the case of the layer structure of the organic electroluminescent device shown in FIGS. 1 to 4, a metal, metal oxide, metal fluoride, or the like, which can be vacuum-deposited and has a small work function for performing electron injection, is used for the back electrode 7. Is done. Metals include magnesium, aluminum, silver, indium, lithium, calcium and alloys thereof. Examples of the metal oxide include lithium oxide, magnesium oxide, and aluminum oxide. Examples of the metal fluoride include lithium fluoride, magnesium fluoride, strontium fluoride, calcium fluoride, and aluminum fluoride. Further, a protective layer may be further provided on the back electrode 7 in order to prevent the element from being deteriorated by moisture or oxygen. Specific materials for the protective layer include metals such as In, Sn, Pb, Au, Cu, Ag, and Al, MgO, and SiO. ₂ , TiO ₂ The protective layer may be formed by a vacuum evaporation method, a sputtering method, a plasma polymerization method, a CVD method, or a coating method.
[0096]
The organic electroluminescent devices shown in FIGS. 1 to 4 first have a hole transport layer 3, a light emitting layer 4, an electron transport layer 5, and / or a transparent electrode 2, depending on the layer configuration of each organic electroluminescent device. Alternatively, the light emitting layer 6 having a charge transporting ability is formed. The hole transporting layer 3, the light emitting layer 4, the electron transporting layer 5, or the light emitting layer 6 having a charge transporting ability is obtained by dissolving or dispersing each of the above materials in a vacuum evaporation method or an appropriate organic solvent. It is formed on the transparent electrode by using a liquid by a spin coating method, a casting method, a dipping method, or the like.
The thickness of each of the hole transporting layer 3, the light emitting layer 4, the electron transporting layer 5, and the light emitting layer 6 having the charge transporting ability is preferably 10 μm or less, particularly preferably in the range of 0.001 to 5 μm. The dispersion state of each of the above materials (the charge transporting polyether, the light emitting material, and the like) may be a molecular dispersion state or a fine particle state such as microcrystal. In the case of a film forming method using a coating liquid, it is necessary to select a dispersion solvent in consideration of the dispersibility and solubility of each of the above materials in order to obtain a molecular dispersion state. In order to disperse the particles in the form of fine particles, a ball mill, a sand mill, a paint shaker, an attritor, a homogenizer, an ultrasonic method, or the like can be used.
Finally, a back electrode 7 is formed on the electron transporting layer or the light emitting layer 6 having charge transporting ability by a vacuum deposition method, a sputtering method, or the like, thereby completing the device.
[0097]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, these embodiments do not limit the present invention.
[0098]
(Example 1)
ITO (manufactured by Sanyo Vacuum Co.) formed on the transparent insulating substrate was patterned by photolithography using a strip-shaped photomask, and further etched to form a strip-shaped ITO electrode (2 mm in width). Next, the ITO glass substrate is washed with a neutral detergent, pure water, acetone (for electronic industry, manufactured by Kanto Chemical) and isopropanol (for electronic industry, manufactured by Kanto Chemical) for 5 minutes each, and then washed. Dried with a coater. A charge-transporting polyether [exemplified compound (6)] was prepared in a 5% by weight dichloroethane solution on the substrate as a hole transporting layer, and the solution was filtered through a 0.1 μm PTFE filter. A 050 μm thin film was formed. The exemplary compound (V-1) was deposited as a light emitting material to form a light emitting layer having a thickness of 0.065 μm. Subsequently, using a metallic mask provided with strip-shaped holes, and finally setting this mask and vapor-depositing an Mg-Ag alloy by co-evaporation, a back electrode having a width of 2 mm and a thickness of 0.15 μm was formed by ITO. The electrode was formed so as to intersect with the electrode. The effective area of the formed organic electroluminescent device is 0.04 cm. ² Met.
[0099]
(Example 2)
1 part by weight of the charge transporting polyether [exemplary compound (7)], 4 parts by weight of poly (N-vinylcarbazole), and 10% by weight of a solution of the exemplary compound (V-1) in dichloroethane were prepared. Filtered through a PTFE filter. Using this solution, a 2 mm-wide strip-shaped ITO electrode was formed by etching as a light-emitting layer having a charge transport ability on an ITO glass substrate etched and washed in the same manner as in Example 1 by a spin coater method. A thin film having a thickness of about 0.15 μm was formed. After being sufficiently dried, a Mg-Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent device is 0.04 cm. ² Met.
[0100]
(Example 3)
As in Example 1, a charge transporting polyether [exemplified compound (15)] having a thickness of 0.050 μm was formed on the ITO glass substrate etched and washed in the same manner as in Example 1. The exemplary compound (V-1) and the exemplary compound (VI-1) were formed to have a thickness of 0.065 μm as the light emitting layer, and the exemplary compound (VII-1) was formed to have a thickness of 0.030 μm as the electron transport layer. Subsequently, an Mg-Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent device is 0.04 cm. ² Met.
[0101]
(Example 4)
An organic electroluminescent device was produced in the same manner as in Example 1, except that Exemplified Compound (8) was used instead of Exemplified Compound (6) used in Example 1.
[0102]
(Example 5)
An organic electroluminescent device was produced in the same manner as in Example 2, except that Exemplified Compound (20) was used instead of Exemplified Compound (7) used in Example 2.
[0103]
(Example 6)
An organic electroluminescent device was produced in the same manner as in Example 3, except that Exemplified Compound (37) was used instead of Exemplified Compound (15) used in Example 3.
[0104]
(Example 7)
An organic electroluminescent device was produced in the same manner as in Example 3, except that Exemplified Compound (39) was used instead of Exemplified Compound (15) used in Example 3.
[0105]
(Example 8)
An organic electroluminescent device was produced in the same manner as in Example 3, except that Exemplified Compound (47) was used instead of Exemplified Compound (15) used in Example 3.
[0106]
(Example 9)
A 1.5% by weight dichloroethane solution of the charge transporting polyether [exemplified compound (6)] used in Example 1 was prepared and filtered with a 0.1 μm PTFE filter. This solution was used to form a hole transport layer on an ITO glass substrate (a glass substrate formed by etching a strip-shaped ITO electrode having a width of 2 mm by etching) which was etched and washed in the same manner as in Example 1 by a spin coater method. A 0.10 μm thin film was formed. The exemplary compound (IV-1) was deposited as a light-emitting material to form a light-emitting layer having a thickness of 0.050 μm. Next, as the electron transporting layer, a charge transporting polyether [exemplified compound (28)] was applied by a spin coater method to form a thin film having a thickness of 0.05 μm. After sufficient drying, a Mg-Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent device is 0.04 cm. ² Met.
[0107]
(Comparative Example 1)
A device was produced in the same manner as in Example 1 except that the compound represented by the following structural formula (IX) was used instead of the exemplary compound (6) used in Example 1 above.
[0108]
Embedded image

[0109]
(Comparative Example 2)
2 parts by weight of polyvinyl carbazole (PVK) as a charge transporting polymer, 0.1 part by weight of the exemplified compound (V-1) as a light emitting material, and 1 part by weight of the compound (VII-1) as an electron transporting material are mixed. A 10% by weight dichloroethane solution was prepared and filtered with a 0.1 μm PTFE filter. Using this solution, a 0.15 μm-thick hole transport layer was formed by applying a dip method on a glass substrate on which a strip-shaped ITO electrode having a width of 2 mm was formed by etching. After sufficient drying, a Mg-Ag alloy was deposited by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to cross the ITO electrode. The effective area of the formed organic electroluminescent device is 0.04 cm. ² Met.
[0110]
(Evaluation)
The organic electroluminescent device manufactured as described above was placed in a vacuum (133.3 × 10 ^-3 At Pa), a DC voltage was applied with the ITO electrode side plus and the Mg-Ag back electrode minus, and the emission was measured to evaluate the maximum brightness and emission color at this time. Table 21 shows the results. In addition, the emission lifetime of the organic electroluminescent device was measured in dry nitrogen. The evaluation of the light emission life was such that the initial luminance was 50 cd / m. ² The current value was set so as to be as follows, and the time required for the luminance to be reduced by half from the initial value by constant current driving was defined as the element lifetime (hour). Table 21 shows the drive current density at this time together with the element life.
[0111]
[Table 21]

[0112]
As is clear from these examples, the organic electroluminescent device of the present invention using the charge transporting polyether having excellent heat durability, solubility in a solvent or a resin, and compatibility, has a high luminance, a high efficiency, and a long lifetime. It can be seen that there is little defect such as a pinhole and the like, and it is easy to increase the area.
[0113]
【The invention's effect】
As described above, according to the present invention, a charge transporting polyether having excellent thermal stability during light emission, storage stability, solubility and compatibility with a solvent or a resin, high light emission intensity, high light emission efficiency, and device life And an organic electroluminescent device which is long and easy to manufacture.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a layer configuration of an organic electroluminescent device of the present invention.
FIG. 2 is a schematic configuration diagram showing an example of a layer configuration of the organic electroluminescent device of the present invention.
FIG. 3 is a schematic configuration diagram illustrating an example of a layer configuration of the organic electroluminescent element of the present invention.
FIG. 4 is a schematic configuration diagram showing an example of a layer configuration of the organic electroluminescent device of the present invention.
[Explanation of symbols]
1 Transparent insulator substrate
2 Transparent electrode
3 hole transport layer
4 Light-emitting layer
5 electron transport layer
6 Emitting layer with charge transport ability
7 Back electrode

Claims (7)

An electroluminescent device comprising one or more organic compound layers sandwiched between a pair of electrodes comprising an anode and a cathode, at least one of which is transparent or translucent, wherein at least one of the organic compound layers has the following general formula: An organic electric field comprising at least one charge transporting polyether comprising a repeating unit containing at least one selected from the structures represented by formulas (I-1) and (I-2) as a partial structure. Light emitting element.

(In the formulas (I-1) and (I-2), X is a substituted or unsubstituted divalent benzene group, a substituted or unsubstituted monovalent polynuclear aromatic hydrocarbon having 2 to 10 aromatic rings.) Represents a substituted or unsubstituted monovalent condensed aromatic hydrocarbon having 2 to 10 aromatic rings or a substituted or unsubstituted monovalent aromatic heterocyclic ring, wherein T is a divalent straight-chain having 1 to 6 carbon atoms. Represents a chain hydrocarbon group or a divalent branched hydrocarbon group having 2 to 10 carbon atoms, m represents an integer of 0 to 3, k represents 0 or 1, and Ar represents the following general formula (II) -1) or a substituent represented by (II-2).

(In the general formulas (II-1) and (II-2), Ar ₁ represents a substituted or unsubstituted monovalent benzene ring, a substituted or unsubstituted monovalent polynuclear aromatic carbon having 2 to 10 aromatics. Containing hydrogen, a substituted or unsubstituted monovalent fused polycyclic aromatic hydrocarbon having 2 to 10 aromatic rings, a substituted or unsubstituted monovalent aromatic heterocycle, or at least one kind of aromatic heterocycle Ar ₂ , Ar _3, and Ar ₄ each independently represent a substituted or unsubstituted divalent benzene ring or a substituted or unsubstituted divalent polynuclear aromatic group having 2 to 10 aromatic atoms; Aromatic hydrocarbons, substituted or unsubstituted divalent fused polycyclic aromatic hydrocarbons having 2 to 10 aromatic rings, substituted or unsubstituted divalent aromatic heterocycles, or at least one aromatic heterocycle a substituted or divalent substituent containing _.R 1, _{R 2} R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group, a cyano group, a halogen group, a substituted amino group, a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group,, R _1, R ₂ , R ₃ and R ₄ may be the same or different, and n represents an integer of 0 to 10.) The organic compound includes at least a light-emitting layer and an electron transport layer, and at least one of the light-emitting layer and the electron transport layer is selected from the structures represented by the general formulas (I-1) and (I-2). The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device comprises at least one kind of charge transporting polyether comprising a repeating unit containing at least one kind as a partial structure. The organic compound layer includes at least a hole transport layer, a light emitting layer, and an electron transport layer, and at least one of the hole transport layer and the electron transport layer is represented by the general formulas (I-1) and (I-2). 2. The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device comprises at least one kind of a charge transporting polyether comprising a repeating unit containing at least one kind selected from the structures shown as a partial structure. The organic compound layer is composed of only a light emitting layer having a charge transport function, and the light emitting layer having the charge transport function is at least one selected from the structures represented by the general formulas (I-1) and (I-2). The organic electroluminescent device according to claim 1, wherein a light emitting layer containing at least one kind of charge transporting polyether composed of a repeating unit containing one kind as a partial structure is formed. The organic compound layer includes at least a hole transport layer and a light-emitting layer having a charge transport function, and at least one of the hole transport layer and the light-emitting layer having the charge transport function has the general formula (I-1) and 2. A light-emitting layer comprising at least one kind of charge transporting polyether comprising a repeating unit containing at least one kind selected from the structures represented by (I-2) as a partial structure. The organic electroluminescent device according to claim 1. The organic electroluminescent device according to claim 2, wherein the light emitting layer having a charge transport function contains a charge transport compound. A charge transporting polyether comprising a repeating unit containing at least one selected from the structures represented by the general formulas (I-1) and (I-2) as a partial structure is represented by the following general formula (III) The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is a polyether.

(In the general formula (III), A represents at least one selected from the structures represented by the general formulas (I-1) and (I-2). R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted group. Represents an aryl group or a substituted or unsubstituted aralkyl group. P represents an integer of 5 to 5,000.)

Images