JP2004087395A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element which has sufficient brightness, which is superior in stability and durability, and in which realization of a large area is possible and manufacturing is easy. <P>SOLUTION: This organic electroluminescent element is constituted of one or a plurality of organic compound layers pinched between a pair of electrodes consisting of a positive electrode and a negative electrode at least one being transparent or semi-transparent. At least one layer of the organic compound layers contains one or more kinds of electric charge transfer polyethers composed of repeated units containing as a partial substructure at least one kind selected from the structure shown in the following general formulae (I-1) and (I-2). <P>COPYRIGHT: (C)2004,JPO

Description

【００１８】
一般式（Ｉ−１）及び（Ｉ−２）中、Ｘは置換または未置換の２価の芳香族基を表す。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価の分枝状炭化水素基を表し、ｋは０または１を表す。Ｒ_１は炭素数１〜１０の飽和もしくは不飽和炭化水素基、または置換もしくは未置換の芳香族基を表し、Ｒ_２は水素原子、炭素数１〜１０の飽和もしくは不飽和炭化水素基、炭素数１〜４のアルコキシ基、シアノ基、ハロゲン原子、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す。
【００１９】
＜２＞　前記有機化合物層が少なくともキャリア輸送能を持つ発光層及び電子輸送層から構成され、前記発光層が、前記一般式（Ｉ−１）及び（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、少なくとも１種含有してなることを特徴とする＜１＞に記載の有機電界発光素子である。
【００２０】
＜３＞　前記有機化合物層が少なくともホール輸送層、発光層及び電子輸送層から構成され、前記発光層が、前記一般式（Ｉ−１）及び（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、少なくとも１種含有してなることを特徴とする＜１＞に記載の有機電界発光素子である。
【００２１】
＜４＞　前記有機化合物層が少なくともキャリア輸送能を持つ発光層から構成され、前記発光層が、前記一般式（Ｉ−１）及び（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、少なくとも１種含有してなることを特徴とする＜１＞に記載の有機電界発光素子である。
【００２２】
＜５＞　前記有機化合物層が少なくともホール輸送層及びキャリア輸送能を持つ発光層から構成され、前記発光層もしくはホール輸送層のうち少なくとも１つの層が、前記一般式（Ｉ−１）及び（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、少なくとも１種含有してなることを特徴とする＜１＞に記載の有機電界発光素子である。
【００２３】
＜６＞　前記発光層が、電荷輸送性材料を含むことを特徴とする＜２＞に記載の有機電界発光素子である。
【００２４】
＜７＞　前記発光層が、電荷輸送性材料を含むことを特徴とする＜３＞に記載の有機電界発光素子である。
【００２５】
＜８＞　前記発光層が、電荷輸送性材料を含むことを特徴とする＜４＞に記載の有機電界発光素子である。
【００２６】
＜９＞　前記発光層が、電荷輸送性材料を含むことを特徴とする＜５＞に記載の有機電界発光素子である。
【００２７】
＜１０＞　前記電荷輸送性ポリエーテルが、下記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜１＞に記載の有機電界発光素子である。
【００２８】
【化４】

【００２９】
上記式中、Ａは上記一般式（Ｉ−１）及び（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、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し、ｐは５〜５０００の整数を表す。
【００３０】
＜１１＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜２＞に記載の有機電界発光素子である。
【００３１】
＜１２＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜３＞に記載の有機電界発光素子である。
【００３２】
＜１３＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜４＞に記載の有機電界発光素子である。
【００３３】
＜１４＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜５＞に記載の有機電界発光素子である。
【００３４】
＜１５＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜６＞に記載の有機電界発光素子である。
【００３５】
＜１６＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜７＞に記載の有機電界発光素子である。
【００３６】
＜１７＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜８＞に記載の有機電界発光素子である。
【００３７】
＜１８＞　前記電荷輸送性ポリエーテルが、上記一般式（ＩＩ）で示されるポリエーテルであることを特徴とする＜９＞に記載の有機電界発光素子である。
【００３８】
なお、本発明の有機ＥＬ素子において、有機化合物層は、機能分離型のもの、例えば、少なくともホール輸送層及び発光層から構成され、該ホール輸送層が前記一般式（Ｉ−１）及び（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してなるものや、キャリア輸送能と発光能を兼ね備えたもの、すなわち、有機化合物層が発光層のみから構成されてなり、該発光層が前記一般式（Ｉ−１）及び（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してなるもののいずれでもよい。
【００３９】
また、本発明の有機ＥＬ素子において、有機化合物層が発光層のみから構成される場合、該発光層には、電荷輸送性材料（電荷輸送性ポリエーテル以外のホール輸送材料、電子輸送材料）を含んでもよい。
【００４０】
【発明の実施の形態】
本発明の有機ＥＬ素子は、少なくとも一方が透明または半透明である陽極及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）及び（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（以下、単に「電荷輸送性ポリエーテル」という場合がある）を１種以上含有することを特徴とする。
【００４１】
【化５】

【００４２】
一般式（Ｉ−１）及び（Ｉ−２）中、Ｘは置換または未置換の２価の芳香族基を表す。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価の分枝状炭化水素基を表し、ｋは０または１を表す。Ｒ_１は炭素数１〜１０の飽和もしくは不飽和炭化水素基、または置換もしくは未置換の芳香族基を表し、Ｒ_２は水素原子、炭素数１〜１０の飽和もしくは不飽和炭化水素基、炭素数１〜４のアルコキシ基、シアノ基、ハロゲン原子、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す。
【００４３】
本発明の有機ＥＬ素子は、前記電荷輸送性ポリエーテルを含有してなる層を有することで、十分な輝度を有し、安定性および耐久性に優れる。さらに、前記電荷輸送性ポリエーテルを用いることで、大面積化可能であり、容易に製造可能である。
【００４４】
具体的には、上記電荷輸送性ポリエーテルを有機化合物層の少なくとも一層に用いることにより、電荷の移動度を大きくすることができるため、低電流で高い発光輝度を有する有機ＥＬ素子を得ることができる。また、電荷輸送層形成にあたり、低分子の電荷輸送材料を高分子材料中に分散（相溶）させる必要がないため、高分子材料のガラス転移温度を低下させることがなく、有機ＥＬ素子の耐熱性、耐久性を向上させることができる。
【００４５】
一般式（Ｉ−１）及び（Ｉ−２）中、Ｘは、置換または未置換の２価の芳香族基を表し、具体的な例としては下記の式（１）〜（１３）が挙げられる。
【００４６】
【化６】

【００４７】
式（１）〜（１３）中、Ｒ_３は、水素原子、炭素数１〜４のアルキル基、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を表し、Ｒ_４〜Ｒ_１２は、それぞれ水素原子、炭素数１〜４のアルキル基、炭素数１〜４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し、ａ、ｂは０または１を表し、Ｖは下記の式（１４）〜（３１）から選択される基を表す。
【００４８】
【化７】

【００４９】
式（１４）〜（３１）中、ｃ、ｄ、ｅは１〜１０の整数、ｆ、ｇ、ｈは０〜１０の整数を表す。
【００５０】
これらの中でも、前記Ｘが下記構造式（３２）または（３３）で示されるビフェニレン構造を有する場合、「Ｔｈｅ　Ｓｉｘｔｈ　ＩｎｔｅｒｎａｔｉｏｎａｌＣｏｎｇｒｅｓｓ　ｏｎ　Ａｄｖａｎｃｅｓ　ｉｎ　Ｎｏｎ−ｉｍｐａｃｔ　Ｐｒｉｎｔｉｎｇ　Ｔｅｃｈｎｏｌｏｇｉｅｓ，３０６，（１９９０）　」にも報告されているように、モビリティーが高いポリマーが得られることから、特に好ましい。
【００５１】
【化８】

【００５２】
なお、一般式（Ｉ−１）及び（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価の分枝状炭化水素基を表し、具体的な例としては以下の構造を挙げることができる。
【００５３】
【化９】

【００５４】
以下、一般式（Ｉ−１）及び（Ｉ−２）で示される構造の具体例を表１〜表１７示すが、本発明はこれら具体例に限定されるわけではない。なお、表１〜表９における構造番号１〜７６は一般式（Ｉ−１）で示される構造の具体例を示し、表１０〜表１７における構造番号７７〜１４０は一般式（Ｉ−２）で示される構造の具体例を示す。
【００５５】
【表１】

【００５６】
【表２】

【００５７】
【表３】

【００５８】
【表４】

【００５９】
【表５】

【００６０】
【表６】

【００６１】
【表７】

【００６２】
【表８】

【００６３】
【表９】

【００６４】
【表１０】

【００６５】
【表１１】

【００６６】
【表１２】

【００６７】
【表１３】

【００６８】
【表１４】

【００６９】
【表１５】

【００７０】
【表１６】

【００７１】
【表１７】

【００７２】
前記電荷輸送性ポリエーテルとしては、下記一般式（ＩＩ）で示されるものが好適に使用される。
【００７３】
【化１０】

【００７４】
上記式中、Ａは上記一般式（Ｉ−１）及び（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、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し、ｐは５〜５０００の整数を表す。
【００７５】
上記アルキル基としては、炭素数１〜１０の範囲のものが好ましく、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の範囲のものが好ましく、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の範囲のものが好ましく、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。
【００７６】
以下、表１８〜表２０に、一般式（ＩＩ）で示される電荷輸送性ポリエーテルの具体的な例を示すが、本発明はこれら具体例に限定されるわけではない。なお、表１８〜表２０において、モノマー列のＡ欄の番号は、前記一般式（Ｉ−１）及び（Ｉ−２）で示される構造の具体例である表１〜表１７で示した構造番号に対応している。以下、各番号を付した具体例、例えば、１５の番号を付した具体例は例示化合物（１５）という。
【００７７】
【表１８】

【００７８】
【表１９】

【００７９】
【表２０】

【００８０】
前記電荷輸送性ポリエーテルの質量平均分子量Ｍｗは、１０，０００〜３００，０００の範囲にあることが好ましく、５０，０００〜２００，０００の範囲にあることがより好ましい。
【００８１】
本発明の電荷輸送性ポリエーテル（電荷輸送性ポリマー）は、下記一般式（ＩＩＩ）及び（ＩＶ）で示されるヒドロキシル基を有する電荷輸送性化合物（電荷輸送性モノマー）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。なお、構造式（ＩＩＩ）及び（ＩＶ）中、Ｘ、Ｔは、前記一般式（Ｉ−１）または（Ｉ−２）におけるＸ、Ｔと同様である。
【００８２】
【化１１】

【００８３】
合成法の一例を示せば、（ＩＩＩ）あるいは（ＩＶ）で表される化合物を無溶媒で加熱溶融し、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で目的とするポリマーを得ることができる。また、溶媒を使用する場合は、脱離した水の除去のため、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を用いることが有効であり、電荷輸送性モノマー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。
【００８４】
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、前記溶媒の沸点付近の温度で反応させることが好ましい。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。
【００８５】
また、上記電荷輸送性ポリマーは、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。この場合触媒量は、電荷輸送性モノマー１当量に対して、酸触媒を１〜１／１０，０００〜１／１０当量の範囲とすることが好ましく、１／１，０００〜１／５０当量の範囲とすることがより好ましい。
【００８６】
この場合も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ことが好ましく、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を、電荷輸送性モノマー１当量に対して、好ましくは１〜１００当量の範囲で、より好ましくは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、前記同様重合中に生成する水を除去するため、上記溶剤の沸点付近の温度で反応させることが好ましい。
【００８７】
さらに、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も好ましい合成方法である。
【００８８】
この場合、用いられる縮合剤量は、電荷輸送性モノマー１当量に対して、１／２〜１０当量の範囲であることが好ましく、１〜３当量の範囲であることがより好ましい。
【００８９】
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付近の温度で反応させることが好ましい。
【００９０】
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反応物を溶解させる。溶剤を用いた場合には、反応液を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撹拌しながら効率よく行うことが好ましい。
【００９１】
上記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の量は、電荷輸送性ポリマー１質量部に対して、１〜１００質量部の範囲であることが好ましく、２〜５０質量部の範囲であることがより好ましい。また、前記貧溶剤の量は、電荷輸送性ポリマー１質量部に対して、１〜１０００質量部の範囲であることが好ましく、１０〜５００質量部の範囲であることがより好ましい。
【００９２】
さらに、前記反応において、電荷輸送性モノマーを２種以上、好ましくは２〜５種、より好ましくは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。このように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、溶解性を制御することができる。
【００９３】
電荷輸送性ポリマーの重合度は、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の範囲であることが好ましく、１０〜３０００の範囲であることがより好ましく、１５〜１０００の範囲であることがさらに好ましい。
【００９４】
電荷輸送性ポリマーの末端基は、電荷輸送性モノマーと同様にヒドロキシル基、すなわち、前記一般式（ＩＩ）における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、上記末端基Ｒを修飾し物性を制御することができる。
【００９５】
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。この場合の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、上記試薬は、末端のヒドロキシル基に対し１〜３当量の範囲で用いられることが好ましく、１〜２当量の範囲で用いることがより好ましい。
【００９６】
その際、塩基触媒を用いることができるが、該塩基触媒としては、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、触媒量としては、末端のヒドロキシル基に対し１〜３当量の範囲であることが好ましく、１〜２当量の範囲であることがより好ましい。上記反応は、０℃から使用する溶剤の沸点付近の温度で行うことができる。
【００９７】
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択される単独溶剤、あるいはこれらの２〜３種の混合溶剤が使用できる。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。
【００９８】
また、例えば前記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、前記Ｒ基をアシル基にすることもできる。用いる酸ハロゲン化物としては特に限定されるものではないが、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挙げられる。
上記酸ハロゲン化物の使用量は、末端のヒドロキシル基に対し１〜３当量の範囲であることが好ましく、１〜２当量の範囲であることがより好ましい。
【００９９】
その際、塩基触媒を用いることができるが、該塩基触媒としては、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、使用量は、前記酸ハロゲン化物に対し１〜３当量の範囲であることが好ましく、１〜２当量の範囲であることがより好ましい。
【０１００】
用いられる溶剤としては、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挙げられる。反応は、０℃から溶剤の沸点付近の温度で行うことができるが、０℃〜３０℃の範囲で行うことが好ましい。
【０１０１】
さらに、無水酢酸等の酸無水物を用いても前記末端のヒドロキシル基をアシル化することができる。この反応において溶剤を用いる場合は、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℃から溶剤の沸点付近の温度で行うことができるが、５０℃から溶剤の沸点の範囲で行うことが好ましい。
【０１０２】
そのほか、モノイソシアネートを用い、電荷輸送性ポリマーの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る。使用量は、末端のヒドロキシル基に対し１〜３当量の範囲であることが好ましく、１〜２当量の範囲であることがより好ましい。
【０１０３】
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挙げることができる。
【０１０４】
反応は、０℃から使用溶剤の沸点付近の温度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第３級アミンを触媒として添加することもできる。
【０１０５】
以上のように、電荷輸送性ポリマーの末端Ｒを各種修飾することができるが、成膜性、モビリティー等の観点からは、末端をメチル基、エチル基、（イソ）プロピル基等のアルキル基、フェニル基、トリル基、メトキシフェニル基等のアリル基とすることが好ましい。
【０１０６】
次に、本発明の有機ＥＬ素子の層構成について詳記する。
本発明の有機ＥＬ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。
【０１０７】
本発明の有機ＥＬ素子においては、有機化合物層が１つの場合は、該有機化合物層はキャリア輸送能を持つ発光層であり、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。また、有機化合物層が複数の場合（機能分離型の場合）は、それらの少なくとも一つは発光層（この発光層はキャリア輸送能を有していてもよいし、有していなくてもよい）であり、他の有機化合物層は、キャリア輸送層、すなわち、ホール輸送層、電子輸送層、または、ホール輸送層及び電子輸送層として構成され、これらの少なくとも一層が、前記電荷輸送性ポリエーテルを含有してなる。
【０１０８】
具体的には、例えば、少なくとも発光層及び電子輸送層から構成される有機ＥＬ素子、少なくともホール輸送層、発光層及び電子輸送層から構成される有機ＥＬ素子、あるいは、少なくともホール輸送層及び発光層から構成される有機ＥＬ素子において、これらの少なくとも一層（発光層、ホール輸送層、電子輸送層）が前記電荷輸送性ポリエーテルを含有してなるもの等が挙げられる。さらに、例えば、有機化合物層が発光層のみから構成されてなり、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ものも挙げることができる。
【０１０９】
また、本発明の有機ＥＬ素子においては、発光層が、電荷輸送性材料（前記電荷輸送性ポリエーテル以外のホール輸送性材料、電子輸送性材料）を含有していることが好ましい。詳しくは、後述する。
【０１１０】
以下、図面を参照しつつ、本発明の有機ＥＬ素子の構成をより詳細に説明するが、本発明はこれらに限定されるわけではない。
図１〜図４は、本発明の有機ＥＬ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は、有機化合物層が複数の場合の一例であり、図３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。
【０１１１】
図１に示す有機ＥＬ素子は、透明絶縁体基板１表面に、透明電極２、キャリア輸送能を持つ発光層６、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ＥＬ素子は、透明絶縁体基板１表面に、透明電極２、ホール輸送層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ＥＬ素子は、透明絶縁体基板１表面に、透明電極２、キャリア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ＥＬ素子は、透明絶縁体基板１表面に、透明電極２、ホール輸送層３、キャリア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。
【０１１２】
なお、図１、図２及び図４に示す有機ＥＬ素子は、発光材料（発光層）が、明確なキャリア輸送性を示さないものを用いる場合に、有機ＥＬ素子の耐久性向上あるいは発光効率の向上を図る目的で、発光層４あるいはキャリア輸送能を持つ発光層６と透明電極２との間にホール輸送層を設けたり、発光層４あるいはキャリア輸送能を持つ発光層６と背面電極７との間に電子輸送層を設けたりした層構成のものである。
【０１１３】
本発明における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は、図１に示される有機ＥＬ素子の層構成の場合には、例えば、キャリア輸送能を持つ発光層６として用いることが好ましい。また、図２に示される有機ＥＬ素子の層構成の場合には、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発光層４、ホール輸送層３としていずれにも用いることができるが、発光層４として用いることが好ましい。また、図３に示される有機ＥＬ素子の層構成の場合には、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キャリア輸送能を持つ発光層６として用いることが好ましい。さらに、図４に示される有機ＥＬ素子の層構成の場合には、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、例えば、ホール輸送層３、キャリア輸送能を持つ発光層６としていずれも用いることができるが、キャリア輸送能を持つ発光層６として用いることが好ましい。
【０１１４】
前記電荷輸送性ポリエーテルを有機化合物層として用いる本発明の有機ＥＬ素子としては、上記各層構成の中で図３、図４の構成が、素子として作製が容易であり、電荷輸送性ポリエーテルの特性を反映でき、十分な輝度、安定性、耐久性を達成できる点で好ましい構成である。
【０１１５】
なお、本発明における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は良好なホール輸送能を有し、例えば前記のように図４で表される発光素子のホール輸送層３にも用いることができる。この場合、キャリア輸送能を持つ発光層６には電子輸送性の発光層が設けられ、代表的な例としては下図（Ｖ−１〜９）に示される化合物を挙げることができる。
【０１１６】
【化１２】

【０１１７】
図１〜図４に示される有機ＥＬ素子の層構成の場合、発光層４もしくはキャリア輸送能を持つ発光層６は、目的に応じて機能（ホール輸送能、あるいは電子輸送能）が付与された前記電荷輸送性ポリエーテルを含有する有機化合物層であることが好ましい。
【０１１８】
この場合の有機化合物層は、基本的には前記電荷輸送性ポリエーテル単独で形成されるが、有機ＥＬ素子に注入されるホールと電子とのバランスを調節するために、前記電荷輸送性ポリエーテル以外の電子輸送材料を、層全体の質量に対して１０〜５０質量％の範囲で分散させてもよい。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を用いることが好ましく、より好ましくは下記例示化合物（ＶＩ）が用いられるが、これに限定されるものではない。
【０１１９】
【化１３】

【０１２０】
同様にホール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ホール輸送材料、好ましくはテトラフェニレンジアミン誘導体を層全体の質量に対して１０〜５０質量％の範囲で同時に分散させて用いてもよい。
【０１２１】
また、発光層４もしくはキャリア輸送能を持つ発光層６には、有機ＥＬ素子の耐久性向上あるいは発光効率の向上を目的として、前記電荷輸送性ポリエーテルと異なる色素化合物をドーピングしてもよい。ドーピングは溶液または分散液中に所定の色素を混合することで行う。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、層全体の質量の０．００１〜４０質量％の範囲であることが好ましく、０．０１〜１０質量％の範囲であることがより好ましい。
【０１２２】
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、発光材料との相溶性がよく、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、ＤＣＭ誘導体、キナクリドン誘導体、ルブレン誘導体、ポルフィリン系化合物等が好適に用いられる。具体例として、下記の化合物（ＶＩＩ−１）〜（ＶＩＩ−４）を挙げることができるが、これらに限定されるものではない。
【０１２３】
【化１４】

【０１２４】
図１〜図４に示される層構成の有機ＥＬ素子の場合、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。また、透明電極２は、透明絶縁体基板１と同様に発光を取り出すため透明であって、かつホールの注入を効率よく行うために仕事関数の大きなものが好ましく、酸化スズインジウム（ＩＴＯ）、酸化スズ（ＮＥＳＡ）、酸化インジウム、酸化亜鉛等の酸化膜、及び蒸着あるいはスパッタされた金、白金、パラジウム等が好ましく用いられる。
【０１２５】
図１及び図２に示される層構成の有機ＥＬ素子の場合、電子輸送層５には、電子輸送能を示す化合物が電荷輸送性材料として用いられる。このような電子輸送層に用いられる電子輸送性材料としては、有機低分子の場合、真空蒸着法により良好な薄膜形成が可能な有機化合物が好ましく用いられ、具体的には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を挙げることができる。また、高分子の場合には、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条件である。電子輸送性材料としては、具体的に下記の化合物（ＶＩＩＩ−１）〜（ＶＩＩＩ−３）が好ましく用いられるが、これらに限定されるものではない。また、他の汎用の樹脂等と混合して用いてもよい。
【０１２６】
【化１５】

【０１２７】
図２及び図４に示される層構成の有機ＥＬ素子の場合、ホール輸送層３には、ホール輸送能を示す化合物が電荷輸送性材料として用いられる。該電荷輸送性材料が有機低分子の場合には、真空蒸着法、もしくは低分子と結着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材料選択の条件とされる。また、ホール輸送能を示す電荷輸送性材料が高分子の場合には、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材料選択の条件である。
【０１２８】
ホール輸送能を示す電荷輸送性材料としては、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、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等が好ましく用いられるが、特に好適な具体例として、下記例示化合物（ＩＸ−１）〜（ＩＸ−８）を挙げることができるが、これらの中では、電荷輸送性ポリエーテルとの相溶性がよいことから、テトラフェニレンジアミン誘導体が好ましく用いられる。また、上記化合物を他の汎用の樹脂等と混合して用いてもよい。
【０１２９】
【化１６】

【０１３０】
図１〜図４に示される層構成の有機ＥＬ素子の場合、背面電極７には、真空蒸着可能で、かつ電子注入を効率よく行うために仕事関数の小さな金属が使用されるが、特にマグネシウム、アルミニウム、銀、インジウム及びこれらの合金が好ましく用いられる。また、背面電極７の表面には、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等が挙げられる。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、コーティング法が適用できる。
【０１３１】
これら図１〜図４に示される有機ＥＬ素子の各層形成は以下のように行われる。まず、透明電極２の表面に各有機ＥＬ素子の層構成に応じて、ホール輸送層３あるいはキャリア輸送能を持つ発光層６を形成する。ホール輸送層３及びキャリア輸送能を持つ発光層６は、上記各材料を真空蒸着法、もしくは有機溶媒中に溶解あるいは分散し、得られた塗布液を用いて前記透明電極２表面に製膜するスピンコーティング法、ディップ法等により形成される。
【０１３２】
次に、各有機ＥＬ素子の層構成に応じて、ホール輸送層３、発光層４、電子輸送層５あるいはキャリア輸送能を持つ発光層６は、上記各材料を、真空蒸着法、もしくは有機溶媒中に溶解あるいは分散し、得られた塗布液を用いて前記透明電極２表面に製膜するスピンコーティング法、ディップ法等を用いることによって形成される。
【０１３３】
形成されるホール輸送層３、発光層４及び電子輸送層５の膜厚は、各々０．１μｍ以下であることが好ましく、特に０．０３〜０．０８μｍの範囲であることが好ましい。また、キャリア輸送能を持つ発光層６の膜厚は、０．０３〜０．２μｍの範囲であることが好ましく、０．０５〜０．１μｍの範囲であることがより好ましい。
【０１３４】
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粒子分散状態でも構わない。塗布液を用いた製膜法の場合、分子分散状態とするためには、分散溶媒は上記各材料の共通溶媒を用いる必要があり、微粒子分散状態とするためには、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、ペイントシェイカー、アトライター、ボールミル、ホモジェナイザー、超音波法等が利用できる。
【０１３５】
そして、最後に、電子輸送層５あるいはキャリア輸送能を持つ発光層６の表面に、背面電極７を真空蒸着法により形成することにより素子が完成される。
【０１３６】
本発明の有機ＥＬ素子は、一対の電極間に、例えば、４〜２０Ｖで、電流密度１〜２００ｍＡ／ｃｍ^２の直流電圧を印加することによって、１００ｃｄ／ｍ^２程度以上に十分発光させることができる。
【０１３７】
【実施例】
以下、実施例によって本発明を説明するが、本発明はこれらの実施例に制限されるものではない。
（実施例１）
２ｍｍ幅の短冊型にエッチングしたＩＴＯガラス基板をイソプロパノール（電子工業用、関東化学社製）で超音波洗浄した後、スピンコーターで乾燥させた。電荷輸送性ポリエーテル（例示化合物（５））の５質量％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、前記ＩＴＯガラス基板表面にディップ法により塗布し、厚さ０．０５０μｍのホール輸送層を形成した。十分乾燥させたこのホール輸送層の表面に、発光材料として昇華精製した前記例示化合物（Ｖ−１）をタングステンボートに入れ、真空蒸着法により蒸着して、膜厚０．０６５μｍのキャリア輸送能を持つ発光層を形成した。この時の真空度は１．３３×１０^−３Ｐａ、ボート温度は３００℃であった。続いてこの発光層の表面に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。作製された有機ＥＬ素子の有効面積は０．０４ｃｍ^２であった。
【０１３８】
以上のように作製した有機ＥＬ素子を、真空中（１．３３×１０^−１Ｐａ）でＩＴＯ電極側をプラス、Ｍｇ−Ａｇ背面電極をマイナスとして１０Ｖの直流電圧を印加し、発光について測定を行い、このときの最高輝度、及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ＥＬ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３５０ｃｄ／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。
【０１３９】
（実施例２）
電荷輸送性ポリエーテル（例示化合物（１３））１質量部と、前記化合物（ＩＸ−１）１質量部とを混合し、１０質量％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表面に、ディップ法により膜厚約０．１５μｍのホール輸送層を形成した。充分乾燥させた後、該ホール輸送層表面に、発光材料として昇華精製した前記例示化合物（Ｖ−１）を実施例１と同様にして蒸着し、厚さ０．０６５μｍのキャリア輸送能を持つ発光層を形成した。さらに、この発光層の表面に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。作製された有機ＥＬ素子の有効面積は０．０４ｃｍ^２であった。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４０】
（実施例３）
実施例１と同様にしてエッチング、洗浄したＩＴＯガラス基板表面に、実施例１同様にして、電荷輸送性ポリエーテル（例示化合物（１９））溶液をディップ法により塗布し、厚さ０．０５０μｍのホール輸送層を形成した。充分乾燥させた後、該ホール輸送層表面に、発光材料として昇華精製した前記例示化合物（Ｖ−１）を実施例１と同様にして蒸着し、厚さ０．０６５μｍの発光層を形成した。次いで該発光層の表面に、前記例示化合物（ＶＩＩＩ−１）を真空度１．３３×１０^−３Ｐａ以下、ボート温度２００℃の条件で真空蒸着し、厚さ０．０３０μｍの電子輸送層を形成した。その後この電子輸送層の表面に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。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４１】
（実施例４）
例示化合物（５）の代わりに例示化合物（２４）を用いた以外は、実施例１と同様にして有機ＥＬ素子を作製した。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４２】
（実施例５）
例示化合物（１３）の代わりに例示化合物（２８）を用いた以外は、実施例２と同様にして有機ＥＬ素子を作製した。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４３】
（実施例６）
例示化合物（１９）の代わりに例示化合物（４３）を用いた以外は、実施例３と同様にして有機ＥＬ素子を作製した。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４４】
（実施例７）
例示化合物（５）の代わりに例示化合物（５７）を用いた以外は、実施例１と同様にして有機ＥＬ素子を作製した。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４５】
（実施例８）
例示化合物（５）の代わりに例示化合物（７３）を用いた以外は、実施例１と同様にして有機ＥＬ素子を作製した。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４６】
（実施例９）
例示化合物（５）２質量部と、発光材料として前記化合物（ＶＩＩ−１）を０．１質量部と、電子輸送材料として前記化合物（ＶＩ）を１質量部とを混合し、１０質量％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表面に、ディップ法により塗布して、膜厚約０．１５μｍのキャリア輸送能を持つ発光層を形成した。十分乾燥させた後、該キャリア輸送能を持つ発光層表面に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。作製された有機ＥＬ素子の有効面積は０．０４ｃｍ^２であった。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４７】
（比較例１）
実施例２において、ホール輸送層を前記一般式（ＩＸ−１）で示される化合物を、真空度１．３３×１０^−３Ｐａ以下、ボート温度２００℃の条件で真空蒸着法で形成した以外は、実施例２と同様にして有機ＥＬ素子を作製した。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４８】
（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質量部、発光材料として前記例示化合物（Ｖ−１）を０．１質量部、電子輸送材料として前記化合物（ＶＩ）を１質量部混合し、１０質量％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表面に、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、該ホール輸送層表面に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。作製された有機ＥＬ素子の有効面積は０．０４ｃｍ^２であった。
上記有機ＥＬ素子について実施例１と同様の評価を行った。結果を表２１に示す。
【０１４９】
【表２１】

【０１５０】
上記実施例に示すように、本発明の有機ＥＬ素子は、駆動電流密度が低いにもかかわらず高い最高輝度を示し、特に実施例２、５、６においては、９００ｃｄ／ｍ^２以上の最高輝度が得られた。これに対し、比較例の有機ＥＬ素子では、十分な最高輝度、素子寿命が得られなかった。
【０１５１】
【発明の効果】
前記一般式（Ｉ−１）及び（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構造単位からなる電荷輸送性ポリエーテルは、有機ＥＬ素子に好適なイオン化ポテンシャルや電荷移動度及び発光特性を持ち、また、スピンコーティング法、ディップ法等を用いて良好な薄膜を形成することが可能であるので、これを用いて形成された本発明の有機ＥＬ素子は、十分に高い輝度を示し、また、膜厚を比較的厚く設定できるため、ピンホール等の不良も少なく、大面積化も容易であり、しかも優れた耐久性を有する。
【図面の簡単な説明】
【図１】本発明の積層型有機ＥＬ素子の一例を示す模式的断面図である。
【図２】本発明の積層型有機ＥＬ素子の他の一例を示す模式的断面図である。
【図３】本発明の有機ＥＬ素子の他の一例を示す模式的断面図である。
【図４】本発明の積層型有機ＥＬ素子の他の一例を示す模式的断面図である。
【符号の説明】
１　透明絶縁体基板
２　透明電極
３　ホール輸送層
４　発光層
５　電子輸送層
６　キャリア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 organic electroluminescent element (hereinafter, referred to as an “organic EL element”) that converts electric energy into light to emit light, and relates to a display element, a backlight, an illumination light source, an electrophotographic exposure apparatus, a sign, a signboard, and the like. The present invention relates to an organic EL device that can be suitably used in the field.
[0002]
[Prior art]
2. Description of the Related Art An electroluminescent element (hereinafter, referred to as an “EL 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, the EL devices using inorganic phosphors are mainly used. However, since an AC voltage of 200 V or more is required for driving, there are problems such as high manufacturing cost and insufficient luminance. are doing.
[0003]
On the other hand, research on an organic EL device using an organic compound was first started using a single crystal such as anthracene, but in the case of a single crystal, the film thickness was as thick as about 1 mm, and a driving voltage of 100 V or more was required. For this reason, thinning by an evaporation method has been attempted (Thin Solid Films, Vol. 94, 171 (1982)). In the light emission of these devices, electrons are injected from one of the electrodes and holes are injected from the other electrode, so that the luminescent material in the device is excited to a high energy level, and the excited luminescent material is grounded. It is a phenomenon that emits extra energy as light when returning to the state.
[0004]
However, in the thin film obtained by the vapor deposition method, the driving voltage is still as high as 30 V, the density of electron / hole carriers in the film is low, and the probability of generating photons due to the recombination of carriers is low, so that sufficient luminance is obtained. It was not obtained and did not reach practical use.
[0005]
However, in 1987, Tang et al. Described a function-separated type in which a hole transporting organic low molecular weight compound and a fluorescent organic low molecular weight compound having an electron transporting ability were sequentially laminated as an extremely thin thin film on a transparent substrate surface by vacuum evaporation. 1000 cd / m 2 at a low driving voltage of about 10 V ² A device capable of obtaining the above high luminance has been reported (Appl. Phys. Lett., Vol. 51, 913 (1987), JP-A-59-194393).・ Development is underway.
[0006]
In the stacked organic EL device, an organic dye that emits fluorescence such as an 8-quinolinol aluminum complex or a coumarin compound is used as the fluorescent organic low-molecular compound. Examples of the hole transporting organic low molecular weight compound include N, N-di (m-tolyl) N, N′-diphenylbenzidine and 1,1-bis [N, N-di (p-tolyl) aminophenyl]. Diamino compounds such as cyclohexane, 4- (N, N-diphenyl) aminobenzaldehyde-N, N-diphenylhydrazone compounds and the like are used.
[0007]
In these stacked organic EL devices, holes and electrons are separated from the fluorescent organic compound while maintaining the carrier balance between the holes and the electrons from the electrode through the charge transporting layer made of the organic compound having a charge transporting property. The holes and the electrons injected into the light emitting layer and confined in the light emitting layer are recombined with each other, thereby realizing high-luminance light emission.
[0008]
However, in this type of organic EL element, a thin film having a thickness of 0.1 μm or less is formed in a plurality of vapor deposition steps, so that a pinhole is easily generated, and strictly controlled conditions are required to obtain sufficient performance. It is necessary to control the film thickness. Therefore, there is a problem that productivity is low and it is difficult to increase the area.
[0009]
Further, the organic EL element has high light emission characteristics, but has a problem in stability during light emission and storage stability (lifetime of the element). That is, since the thickness of the layer formed of the organic compound in the organic EL element is very thin, from several tens to several hundreds of nanometers, the voltage applied per unit thickness becomes very high, and is several mA / cm. ² , It generates a large amount of Joule heat. For this reason, the charge transporting low molecular weight compound and the fluorescent organic low molecular weight compound formed in an amorphous glass state by vapor deposition gradually crystallize and finally melt, and many phenomena such as a decrease in luminance and dielectric breakdown are observed. Can be Furthermore, there has been a problem that deterioration over time due to long-term use and deterioration due to an atmosphere containing oxygen, moisture, and the like occur.
[0010]
Therefore, in order to solve the above-mentioned problem concerning the thermal stability of the EL element, a star-burst amine, which can obtain a stable amorphous glass state as a hole transporting material, is used (for example, the 40th Applied Physics Related Conference, 30a-SZK-14 (1993), etc.), and EL devices using a polymer in which triphenylamine is introduced into the side chain of polyphosphazene (Preprints of the 42nd Polymer Symposium, 20J21 (1993)). ing.
[0011]
However, these materials alone have an energy barrier due to the ionization potential of the hole transporting material, so that the hole injecting property from the anode or the hole injecting property into the light emitting layer cannot be satisfied. 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 cannot be obtained and sufficient There are also problems such as lack of brightness.
[0012]
On the other hand, research and development of a single-layer organic EL element have been promoted with the aim of solving the problems relating to productivity and a large area in a stacked organic EL element, and high conductivity such as poly (p-phenylenevinylene) has been developed. A device using molecules (Nature, Vol. 357, 477 (1992), Nature, Vol. 397, 121 (1999)) or a device in which an electron transporting material and a fluorescent dye are mixed in a hole transporting polyvinyl carbazole (No. 38) Proceedings of the Joint Lecture Meeting on Applied Physics, 31p-G-12 (1991)), but the brightness, luminous efficiency, etc., are still inferior to those of stacked organic EL devices using organic low-molecular compounds. .
[0013]
Further, in the fabrication method, it is reported that a wet coating method is desirable from the viewpoint of simplification of manufacturing, workability, large area, cost, and the like, and that an element can be obtained by a casting method (50th report). Proceedings of the Japan Society of Applied Physics, 29p-ZP-5 (1989), 51st Proceedings of the Japan Society of Applied Physics, 28a-PB-7 (1990)). However, the charge transporting material has poor solubility and compatibility with solvents and resins, and thus is easily crystallized, and thus has a problem in production or characteristics.
[0014]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the conventional technology. That is, an object of the present invention is to provide an organic EL element which has sufficient luminance, is excellent in stability and durability, can have a large area, and is easy to manufacture.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have conducted intensive studies on the charge transporting material, and as a result, at least one selected from the structures represented by the following general formulas (I-1) and (I-2) as a partial structure. When used as a light-emitting material because the charge-transporting polyether contains not only has good charge injection properties, charge mobility, and thin film forming ability as an organic EL element, but also has extremely good light-emitting properties in a solid state. In addition, they have found that they function as elements having excellent luminance and luminous efficiency, and have completed the present invention.
[0016]
That is, the present invention
<1> An electroluminescent device comprising one or a plurality of 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 is 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. The organic electroluminescent device described above.
[0017]
Embedded image

[0018]
In the general formulas (I-1) and (I-2), X represents a substituted or unsubstituted divalent aromatic group. 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 k represents 0 or 1. R ₁ Represents a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic group; ₂ Is a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a halogen atom, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted group Represents an aralkyl group.
[0019]
<2> The organic compound layer includes at least a light emitting layer having a carrier transporting ability and an electron transporting layer, and the light emitting layer is selected from the structures represented by the general formulas (I-1) and (I-2). <1> The organic electroluminescent device according to <1>, further comprising at least one kind of charge transporting polyether comprising a repeating unit containing at least one kind as a partial structure.
[0020]
<3> The organic compound layer includes at least a hole transport layer, a light emitting layer, and an electron transport layer, and the light emitting layer is selected from the structures represented by the general formulas (I-1) and (I-2). <1> The organic electroluminescent device according to <1>, wherein the organic electroluminescent device includes at least one kind of charge transporting polyether including a repeating unit containing at least one kind as a partial structure.
[0021]
<4> The organic compound layer includes at least a light emitting layer having a carrier transporting ability, and the light emitting layer is at least one selected from the structures represented by the general formulas (I-1) and (I-2). <1> The organic electroluminescent device according to <1>, comprising at least one kind of charge transporting polyether comprising a repeating unit containing as a partial structure.
[0022]
<5> The organic compound layer includes at least a hole transporting layer and a light emitting layer having a carrier transporting ability, and at least one of the light emitting layer and the hole transporting layer has the general formula (I-1) or (I) <2> The organic electric field according to <1>, wherein the organic electric field comprises at least one kind of a charge transporting polyether comprising a repeating unit containing at least one kind selected from the structures represented by -2) as a partial structure. It is a light emitting element.
[0023]
<6> The organic electroluminescent device according to <2>, wherein the light emitting layer contains a charge transporting material.
[0024]
<7> The organic electroluminescent device according to <3>, wherein the light emitting layer contains a charge transporting material.
[0025]
<8> The organic electroluminescent device according to <4>, wherein the light emitting layer contains a charge transporting material.
[0026]
<9> The organic electroluminescent device according to <5>, wherein the light emitting layer contains a charge transporting material.
[0027]
<10> The organic electroluminescent device according to <1>, wherein the charge transporting polyether is a polyether represented by the following general formula (II).
[0028]
Embedded image

[0029]
In the above formula, A represents at least one selected from the structures represented by the above general formulas (I-1) and (I-2), and R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, Alternatively, it represents a substituted or unsubstituted aralkyl group, and p represents an integer of 5 to 5000.
[0030]
<11> The organic electroluminescent device according to <2>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0031]
<12> The organic electroluminescent device according to <3>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0032]
<13> The organic electroluminescent device according to <4>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0033]
<14> The organic electroluminescent device according to <5>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0034]
<15> The organic electroluminescent device according to <6>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0035]
<16> The organic electroluminescent device according to <7>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0036]
<17> The organic electroluminescent device according to <8>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0037]
<18> The organic electroluminescent device according to <9>, wherein the charge transporting polyether is a polyether represented by the general formula (II).
[0038]
In the organic EL device of the present invention, the organic compound layer is of a function-separated type, for example, at least comprises a hole transport layer and a light emitting layer, and the hole transport layer is composed of the general formulas (I-1) and (I). -2) those containing a charge-transporting polyether composed of a repeating unit containing at least one selected from the structures represented by -2 as a partial structure, and those having both carrier-transporting ability and light-emitting ability, ie, organic The compound layer is composed of only a light-emitting layer, and the light-emitting layer is composed of a repeating unit containing as a partial structure at least one selected from the structures represented by formulas (I-1) and (I-2). Any of those containing a charge transporting polyether may be used.
[0039]
Further, in the organic EL device of the present invention, when the organic compound layer is composed of only the light emitting layer, the light emitting layer contains a charge transporting material (a hole transporting material other than the charge transporting polyether, an electron transporting material). May be included.
[0040]
BEST MODE FOR CARRYING OUT THE INVENTION
The organic EL 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. Is a charge transporting polyether comprising a repeating unit containing at least one selected from the structures represented by the following general formulas (I-1) and (I-2) as a partial structure (hereinafter simply referred to as "charge transporting polyether"). (May be referred to as "ether").
[0041]
Embedded image

[0042]
In the general formulas (I-1) and (I-2), X represents a substituted or unsubstituted divalent aromatic group. 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 k represents 0 or 1. R ₁ Represents a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted aromatic group; ₂ Is a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a halogen atom, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted group Represents an aralkyl group.
[0043]
The organic EL device of the present invention has sufficient luminance and excellent stability and durability by having the layer containing the charge transporting polyether. Further, by using the charge transporting polyether, it is possible to increase the area, and it is easy to manufacture.
[0044]
Specifically, by using the charge-transporting polyether for at least one of the organic compound layers, charge mobility can be increased, so that an organic EL element having high emission luminance at low current can be obtained. it can. Further, in forming the charge transport layer, it is not necessary to disperse (compatible) a low-molecular charge transport material in the polymer material, so that the glass transition temperature of the polymer material is not lowered and the heat resistance of the organic EL element is reduced. Properties and durability can be improved.
[0045]
In the general formulas (I-1) and (I-2), X represents a substituted or unsubstituted divalent aromatic group, and specific examples include the following formulas (1) to (13). Can be
[0046]
Embedded image

[0047]
In the formulas (1) to (13), R ₃ Represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group; ₄ ~ R ₁₂ Each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, or a halogen atom; Represents 0 or 1, and V represents a group selected from the following formulas (14) to (31).
[0048]
Embedded image

[0049]
In the formulas (14) to (31), c, d, and e represent integers of 1 to 10, and f, g, and h represent integers of 0 to 10.
[0050]
Among them, when X has a biphenylene structure represented by the following structural formula (32) or (33), it is also reported in "The Sixth International Congress on Advances in Non-impact Printing Technologies, 306, (1990)". As described above, a polymer having high mobility can be obtained, which is particularly preferable.
[0051]
Embedded image

[0052]
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. Represents a group, and specific examples include the following structures.
[0053]
Embedded image

[0054]
Hereinafter, specific examples of the structures represented by the general formulas (I-1) and (I-2) are shown in Tables 1 to 17, but the present invention is not limited to these specific examples. Structure numbers 1 to 76 in Tables 1 to 9 show specific examples of the structure represented by the general formula (I-1), and structure numbers 77 to 140 in Tables 10 to 17 correspond to the general formula (I-2) A specific example of the structure represented by is shown.
[0055]
[Table 1]

[0056]
[Table 2]

[0057]
[Table 3]

[0058]
[Table 4]

[0059]
[Table 5]

[0060]
[Table 6]

[0061]
[Table 7]

[0062]
[Table 8]

[0063]
[Table 9]

[0064]
[Table 10]

[0065]
[Table 11]

[0066]
[Table 12]

[0067]
[Table 13]

[0068]
[Table 14]

[0069]
[Table 15]

[0070]
[Table 16]

[0071]
[Table 17]

[0072]
As the charge transporting polyether, those represented by the following general formula (II) are preferably used.
[0073]
Embedded image

[0074]
In the above formula, A represents at least one selected from the structures represented by the above general formulas (I-1) and (I-2), and R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, Alternatively, it represents a substituted or unsubstituted aralkyl group, and p represents an integer of 5 to 5000.
[0075]
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, and examples thereof include a benzyl group and a phenethyl group. 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.
[0076]
Hereinafter, specific examples of the charge transporting polyether represented by the general formula (II) are shown in Tables 18 to 20, but the present invention is not limited to these specific examples. In Tables 18 to 20, the numbers in column A of the monomer column are the structures shown in Tables 1 to 17 which are specific examples of the structures represented by the general formulas (I-1) and (I-2). It corresponds to the number. Hereinafter, specific examples assigned with respective numbers, for example, specific examples assigned with a number of 15 are referred to as Exemplified Compound (15).
[0077]
[Table 18]

[0078]
[Table 19]

[0079]
[Table 20]

[0080]
The mass average molecular weight Mw of the charge transporting polyether is preferably in the range of 10,000 to 300,000, and more preferably in the range of 50,000 to 200,000.
[0081]
The charge transporting polyether (charge transporting polymer) of the present invention is obtained by condensing a hydroxyl group-containing charge transporting compound (charge transporting monomer) represented by the following general formulas (III) and (IV) between molecules. Thus, it can be easily manufactured. In the structural formulas (III) and (IV), X and T are the same as X and T in the general formula (I-1) or (I-2).
[0082]
Embedded image

[0083]
As an example of the synthesis method, the compound represented by (III) or (IV) is heated and melted without a solvent, and the reaction is carried out under reduced pressure in order to promote the polymerization reaction by elimination of water. A polymer can be obtained. When a solvent is used, it is effective to use a solvent azeotropic with water, for example, trichloroethane, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene, etc., in order to remove desorbed water. It is used in the range of 1 to 100 equivalents, preferably 2 to 50 equivalents, relative to 1 equivalent of the charge transporting monomer.
[0084]
The reaction temperature can be arbitrarily set, but the reaction is preferably performed at a temperature near 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.
[0085]
Further, the charge transporting polymer may 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 amount of the catalyst is preferably in the range of 1 to 1 / 10,000 to 1/10 equivalent, and more preferably 1/1000 to 1/50 equivalent to 1 equivalent of the charge transporting monomer. More preferably, it is within the range.
[0086]
In this case, it is preferable to use a solvent capable of azeotropic distillation with water in order to remove water generated during the polymerization.For example, trichloroethane, toluene, chlorobenzene, dichlorobenzene, nitrobenzene, 1-chloronaphthalene, etc. It is preferably used in the range of 1 to 100 equivalents, more preferably in the range of 2 to 50 equivalents, relative to 1 equivalent of the reactive monomer.
The reaction temperature can be arbitrarily set, but it is preferable to carry out the reaction at a temperature near the boiling point of the solvent in order to remove water generated during the polymerization as in the above case.
[0087]
Furthermore, alkyl isocyanates such as cyclohexyl isocyanate, alkyl isocyanates such as cyclohexyl cyanide, cyanate esters such as p-tolyl cyanate and 2,2-bis (4-cyanatophenyl) propane, and dichlorohexylcarbodiimide (DCC ) And a method using a condensing agent such as trichloroacetonitrile are also preferable synthesis methods.
[0088]
In this case, the amount of the condensing agent used is preferably in the range of 1/2 to 10 equivalents, more preferably in the range of 1 to 3 equivalents, relative to 1 equivalent of the charge transporting monomer.
[0089]
As a solvent to be used, toluene, chlorobenzene, dichlorobenzene, 1-chloronaphthalene and the like are effective, and are used in a range of 1 to 100 equivalents, preferably 2 to 50 equivalents to 1 equivalent of the charge transporting monomer. The reaction temperature can be arbitrarily set, but the reaction is preferably carried out at a temperature from room temperature to around the boiling point of the solvent.
[0090]
After the reaction, if no solvent is used, the reactants are dissolved in a soluble solvent. When a solvent is used, the reaction solution is directly dropped into a poor solvent in which an alcohol such as methanol or ethanol or a charge-transporting polymer such as acetone is difficult to dissolve, thereby precipitating the charge-transporting polymer. After separating the polymer, 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 efficiently perform the reprecipitation while stirring with a mechanical stirrer or the like.
[0091]
The amount of the solvent for dissolving the charge transporting polymer in the reprecipitation treatment is preferably in the range of 1 to 100 parts by weight, and more preferably 2 to 50 parts by weight, per 1 part by weight of the charge transporting polymer. Is more preferable. The amount of the poor solvent is preferably in the range of 1 to 1000 parts by mass, more preferably 10 to 500 parts by mass, per 1 part by mass of the charge transporting polymer.
[0092]
Further, in the above reaction, by using two or more, preferably two to five, and more preferably two to three kinds of charge transporting monomers, a copolymer can be synthesized. Thus, by copolymerizing different kinds of charge transporting monomers, it is possible to control electric properties, film formability, and solubility.
[0093]
If the degree of polymerization of the charge transporting polymer is too low, the film formability is inferior, and a strong film is hardly obtained. Also, if it is too high, the solubility in a solvent becomes low, and the processability deteriorates. It is preferably in the range, more preferably in the range of 10-3000, and even more preferably in the range of 15-1000.
[0094]
The terminal group of the charge transporting polymer may be a hydroxyl group as in the case of the charge transporting monomer, that is, R in the general formula (II) may be a hydrogen atom, but polymer properties such as solubility, film formability, and mobility. In the case where is affected, the terminal group R can be modified to control the physical properties.
[0095]
For example, the terminal hydroxyl group can be alkyl etherified with an alkyl sulfate, an alkyl iodide, or the like. Specific reagents in this case can be arbitrarily selected from dimethyl sulfate, diethyl sulfate, methyl iodide, ethyl iodide and the like, and the above reagent is used in a range of 1 to 3 equivalents to the terminal hydroxyl group. It is preferable to use it in the range of 1 to 2 equivalents.
[0096]
At this time, a base catalyst can be used, and the base catalyst can be arbitrarily selected from sodium hydroxide, potassium hydroxide, sodium hydride, sodium metal, and the like. Is preferably in the range of 1 to 3 equivalents, more preferably in the range of 1 to 2 equivalents. The above reaction can be carried out at a temperature from 0 ° C. to around the boiling point of the solvent used.
[0097]
In addition, as the solvent used at that time, selected from inert solvents such as benzene, toluene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone. Or a mixture of two or three of these solvents. Further, depending on the reaction, a quaternary ammonium salt such as tetra-n-butylammonium iodide can be used as a phase transfer catalyst.
[0098]
In addition, for example, the terminal hydroxyl group may be acylated using an acid halide to convert the R group into an acyl group. The acid halide to be used is not particularly limited. Chloride, o-toluoyl chloride, m-toluoyl chloride, p-toluoyl chloride and the like.
The amount of the acid halide to be used is preferably in the range of 1 to 3 equivalents, more preferably in the range of 1 to 2 equivalents, relative to the terminal hydroxyl group.
[0099]
At that time, a base catalyst can be used, and the base catalyst can be arbitrarily selected from pyridine, dimethylaminopyridine, trimethylamine, triethylamine, and the like, and the used amount is 1 to 3 equivalents based on the acid halide. , And more preferably in the range of 1 to 2 equivalents.
[0100]
Examples of the solvent to be used include benzene, toluene, methyl chloride, tetrahydrofuran, methyl ethyl ketone and the like. The reaction can be carried out at a temperature from 0 ° C. to near the boiling point of the solvent, but is preferably carried out in a range of 0 ° C. to 30 ° C.
[0101]
Further, the terminal hydroxyl group can be acylated by using an acid anhydride such as acetic anhydride. When a solvent is used in this reaction, an inert solvent such as benzene, toluene, and chlorobenzene can be used. The reaction can be carried out at a temperature from 0 ° C. to around the boiling point of the solvent, but is preferably carried out within a range from 50 ° C. to the boiling point of the solvent.
[0102]
In addition, a urethane residue (—CONH—R ′) can be introduced into the terminal of the charge transporting polymer 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. The amount used is preferably in the range of 1 to 3 equivalents, more preferably in the range of 1 to 2 equivalents, relative to the terminal hydroxyl group.
[0103]
Examples of the solvent used at that time include benzene, toluene, chlorobenzene, dichlorobenzene, methylene chloride, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like. Can be.
[0104]
The reaction can be carried out at a temperature from 0 ° C. to around the boiling point of the solvent used. If the reaction does not proceed easily, 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 is added as a catalyst. You can also.
[0105]
As described above, the terminal R of the charge-transporting polymer can be variously modified. However, from the viewpoints of film-forming properties, mobility and the like, the terminal is an alkyl group such as a methyl group, an ethyl group, or an (iso) propyl group; Allyl groups such as phenyl, tolyl, and methoxyphenyl are preferred.
[0106]
Next, the layer structure of the organic EL device of the present invention will be described in detail.
The organic EL 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.
[0107]
In the organic EL device of the present invention, when there is one organic compound layer, the organic compound layer is a light emitting layer having a carrier transporting ability, and the light emitting layer contains the charge transporting polyether. When there are a plurality of organic compound layers (function-separated type), at least one of them has a light-emitting layer (this light-emitting layer may or may not have a carrier transporting ability). ), And the other organic compound layer is configured as a carrier transporting layer, that is, a hole transporting layer, an electron transporting layer, or a hole transporting layer and an electron transporting layer, at least one of which is the charge transporting polyether. It contains.
[0108]
Specifically, for example, an organic EL device composed of at least a light emitting layer and an electron transport layer, an organic EL device composed of at least a hole transport layer, a light emitting layer and an electron transport layer, or at least a hole transport layer and a light emitting layer And an organic EL device comprising at least one of these (a light-emitting layer, a hole transport layer, and an electron transport layer) containing the charge transporting polyether. Further, for example, there can be mentioned a layer in which the organic compound layer is constituted only of the light emitting layer, and the light emitting layer contains the charge transporting polyether.
[0109]
In the organic EL device of the present invention, it is preferable that the light emitting layer contains a charge transporting material (a hole transporting material other than the charge transporting polyether, an electron transporting material). Details will be described later.
[0110]
Hereinafter, the configuration of the organic EL device of the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.
FIGS. 1 to 4 are schematic cross-sectional views for explaining the layer structure of the organic EL device of the present invention. FIGS. 1, 2 and 4 show examples in which a plurality of organic compound layers are provided. 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.
[0111]
The organic EL device shown in FIG. 1 is formed by sequentially laminating a transparent electrode 2, a light emitting layer 6 having a carrier transporting ability, an electron transporting layer 5, and a back electrode 7 on the surface of a transparent insulator substrate 1. The organic EL 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 the surface of a transparent insulator substrate 1. The organic EL device shown in FIG. 3 is formed by sequentially laminating a transparent electrode 2, a light emitting layer 6 having a carrier transporting ability, and a back electrode 7 on the surface of a transparent insulator substrate 1. The organic EL 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 a carrier transport ability, and a back electrode 7 on the surface of a transparent insulator substrate 1. Hereinafter, each will be described in detail.
[0112]
In the case where the organic EL element shown in FIGS. 1, 2 and 4 uses a light-emitting material (light-emitting layer) that does not show a clear carrier transporting property, the organic EL element has improved durability or improved luminous efficiency. For the purpose of improvement, a hole transporting layer may be provided between the light emitting layer 4 or the light emitting layer 6 having a carrier transporting ability and the transparent electrode 2, or the light emitting layer 4 or the light emitting layer 6 having a carrier transporting ability may be provided with the back electrode 7. It has a layer configuration in which an electron transporting layer is provided between them.
[0113]
The organic compound layer containing the charge transporting polyether in the present invention is preferably used, for example, as the light emitting layer 6 having a carrier transporting ability in the case of the layer configuration of the organic EL device shown in FIG. . In the case of the layer structure of the organic EL device shown in FIG. 2, the organic compound layer containing the charge transporting polyether can be used as both the light emitting layer 4 and the hole transport layer 3. It is preferable to use as the light emitting layer 4. In the case of the layer configuration of the organic EL device shown in FIG. 3, it is preferable to use an organic compound layer containing the charge transporting polyether as the light emitting layer 6 having a carrier transporting ability. Further, in the case of the layer structure of the organic EL device shown in FIG. 4, the organic compound layer containing the charge transporting polyether is used as, for example, the hole transporting layer 3 and the light emitting layer 6 having a carrier transporting ability. Any of them can be used, but it is preferable to use it as the light emitting layer 6 having a carrier transporting ability.
[0114]
As the organic EL device of the present invention using the charge-transporting polyether as the organic compound layer, the structure shown in FIGS. This is a preferable configuration in that characteristics can be reflected and sufficient luminance, stability, and durability can be achieved.
[0115]
The organic compound layer containing the charge-transporting polyether in the present invention has a good hole-transporting ability, and is used, for example, for the hole-transporting layer 3 of the light-emitting device shown in FIG. 4 as described above. be able to. In this case, the light-emitting layer 6 having a carrier-transporting ability is provided with a light-emitting layer having an electron-transporting property, and typical examples include the compounds shown in the following figures (V-1 to 9).
[0116]
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[0117]
In the case of the layer structure of the organic EL device shown in FIGS. 1 to 4, the light-emitting layer 4 or the light-emitting layer 6 having a carrier transport ability has a function (a hole transport ability or an electron transport ability) according to the purpose. An organic compound layer containing the charge transporting polyether is preferable.
[0118]
In this case, the organic compound layer is basically formed of the charge transporting polyether alone. However, in order to adjust the balance between holes and electrons injected into the organic EL device, the charge transporting polyether is used. Other electron transporting materials may be dispersed in the range of 10 to 50% by mass with respect to the mass of the entire layer. As such an electron transporting material, it is preferable to use an organic compound that does not show strong electron interaction with the charge transporting polyether, and more preferably, the following exemplified compound (VI), but is not limited thereto. Not something.
[0119]
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[0120]
Similarly, in order to adjust the hole mobility, a hole transporting material other than the charge transporting polyether, preferably a tetraphenylenediamine derivative, is used by being simultaneously dispersed in the range of 10 to 50% by mass based on the mass of the entire layer. Is also good.
[0121]
The light emitting layer 4 or the light emitting layer 6 having a carrier transporting ability may be doped with a dye compound different from the charge transporting polyether for the purpose of improving the durability or the luminous efficiency of the organic EL device. The doping is performed by mixing a predetermined dye in a solution or a dispersion. The doping ratio of the dye compound in the light emitting layer is preferably in the range of 0.001 to 40% by mass, more preferably in the range of 0.01 to 10% by mass of the total mass of the layer.
[0122]
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. DCM derivatives, quinacridone derivatives, rubrene derivatives, porphyrin-based compounds Etc. are preferably used. Specific examples include the following compounds (VII-1) to (VII-4), but are not limited thereto.
[0123]
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[0124]
In the case of the organic EL device having the layer configuration shown in FIGS. 1 to 4, the transparent insulator substrate 1 is preferably transparent to extract light emission, and glass, a plastic film, or the like is used. The transparent electrode 2 is preferably transparent, like the transparent insulator substrate 1, for extracting light emission, and has a large work function for efficiently injecting holes. Indium tin oxide (ITO), oxide Oxide films such as tin (NESA), indium oxide, and zinc oxide, and gold, platinum, and palladium deposited or sputtered are preferably used.
[0125]
In the case of the organic EL device having the layer configuration shown in FIGS. 1 and 2, a compound having an electron transporting ability is used for the electron transporting layer 5 as a charge transporting material. As the electron transporting material used for such an electron transporting layer, in the case of a low organic molecule, an organic compound capable of forming a good thin film by a vacuum deposition method is preferably used. Specifically, an oxadiazole derivative, a nitro compound Substituted fluorenone derivatives, diphenoquinone derivatives, thiopyran dioxide derivatives, fluorenylidenemethane derivatives and the like can be mentioned. In the case of a polymer, it is a condition that a good thin film can be formed by applying and drying a solution or dispersion containing the polymer itself. As the electron transporting material, specifically, the following compounds (VIII-1) to (VIII-3) are preferably used, but are not limited thereto. Further, it may be used by mixing with other general-purpose resins.
[0126]
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[0127]
In the case of the organic EL device having the layer configuration shown in FIGS. 2 and 4, a compound having a hole transporting ability is used for the hole transporting layer 3 as a charge transporting material. When the charge-transporting material is a low-molecular organic material, it is preferable that a good thin film can be formed by vacuum evaporation, or by applying and drying a solution or dispersion containing a low-molecular compound and a binder resin. Condition. When the charge transporting material having hole transporting ability is a polymer, the condition for selecting a material is that a good thin film can be formed by applying and drying a solution or dispersion containing itself. .
[0128]
As the charge-transporting material having a hole-transporting property, a tetraphenylenediamine derivative, a triphenylamine derivative, a carbazole derivative, a stilbene derivative, an arylhydrazone derivative, a porphyrin-based compound, and the like are preferably used. Illustrative compounds (IX-1) to (IX-8) can be mentioned, and among these, a tetraphenylenediamine derivative is preferably used because of its good compatibility with the charge transporting polyether. Further, the above compound may be used as a mixture with another general-purpose resin or the like.
[0129]
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[0130]
In the case of the organic EL device having the layer configuration shown in FIGS. 1 to 4, a metal having a small work function is used for the back electrode 7 so that vacuum deposition is possible and electron injection is performed efficiently. , Aluminum, silver, indium and alloys thereof are preferably used. Further, a protective layer may be further provided on the surface of 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 And resin such as polyethylene resin, polyurea resin and polyimide resin. For forming the protective layer, a vacuum evaporation method, a sputtering method, a plasma polymerization method, a CVD method, and a coating method can be applied.
[0131]
Each layer of the organic EL device shown in FIGS. 1 to 4 is formed as follows. First, a hole transport layer 3 or a light emitting layer 6 having a carrier transport ability is formed on the surface of the transparent electrode 2 according to the layer configuration of each organic EL element. The hole transport layer 3 and the light emitting layer 6 having a carrier transport ability are formed on the surface of the transparent electrode 2 using the obtained coating solution by dissolving or dispersing each of the above materials in a vacuum evaporation method or an organic solvent. It is formed by a spin coating method, a dipping method, or the like.
[0132]
Next, depending on the layer configuration of each organic EL element, the hole transporting layer 3, the light emitting layer 4, the electron transporting layer 5, or the light emitting layer 6 having a carrier transporting ability is formed by applying the above materials to each other by a vacuum evaporation method or an organic solvent. It is formed by dissolving or dispersing in the inside, and using a spin coating method, a dipping method, or the like in which a film is formed on the surface of the transparent electrode 2 using the obtained coating solution.
[0133]
The thicknesses of the formed hole transport layer 3, light emitting layer 4, and electron transport layer 5 are each preferably 0.1 μm or less, and particularly preferably in the range of 0.03 to 0.08 μm. Further, the thickness of the light emitting layer 6 having a carrier transporting ability is preferably in the range of 0.03 to 0.2 μm, and more preferably in the range of 0.05 to 0.1 μm.
[0134]
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 dispersion state. In the case of a film-forming method using a coating solution, in order to obtain a molecular dispersion state, it is necessary to use a common solvent of each of the above materials as the dispersion solvent. Must be selected in consideration of the dispersibility and solubility of the polymer. In order to disperse the particles in the form of fine particles, a ball mill, a sand mill, a paint shaker, an attritor, a ball mill, a homogenizer, an ultrasonic method, or the like can be used.
[0135]
Finally, a back electrode 7 is formed on the surface of the electron transport layer 5 or the light emitting layer 6 having a carrier transport ability by a vacuum evaporation method, thereby completing the device.
[0136]
The organic EL device according to the present invention may have a current density of 1 to 200 mA / cm between a pair of electrodes at, for example, 4 to 20 V. ² By applying a DC voltage of 100 cd / m ² It is possible to emit light more than enough.
[0137]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.
(Example 1)
The strip-shaped ITO glass substrate having a width of 2 mm was ultrasonically cleaned with isopropanol (for use in the electronics industry, manufactured by Kanto Chemical Co., Ltd.), and then dried with a spin coater. A 5% by mass solution of a charge transporting polyether (exemplified compound (5)) in dichloroethane was prepared, filtered through a 0.1 μm PTFE filter, and then applied to the surface of the ITO glass substrate by a dipping method to obtain a thickness of 0.050 μm. Was formed. The sublimated and purified example compound (V-1) as a luminescent material was put into a tungsten boat and vapor-deposited by a vacuum vapor deposition method on the sufficiently dried surface of the hole transport layer to have a carrier transport ability of 0.065 μm in thickness. A light emitting layer was formed. The degree of vacuum at this time is 1.33 × 10 ^-3 Pa, the boat temperature was 300 ° C. Subsequently, a Mg-Ag alloy was deposited on the surface of the light emitting layer by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to intersect the ITO electrode. The effective area of the manufactured organic EL device is 0.04 cm. ² Met.
[0138]
The organic EL device manufactured as described above was placed in a vacuum (1.33 × 10 ^-1 At Pa), a DC voltage of 10 V 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. The emission lifetime of the organic EL device was measured in dry nitrogen. The evaluation of the light emission life was such that the initial luminance was 350 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.
[0139]
(Example 2)
One part by mass of the charge transporting polyether (exemplified compound (13)) and 1 part by mass of the compound (IX-1) were mixed to prepare a 10% by mass dichloroethane solution, and the solution was filtered through a 0.1 μm PTFE filter. . Using this solution, a hole transport layer having a thickness of about 0.15 μm was formed by dipping on the surface of a glass substrate on which a rectangular ITO electrode having a width of 2 mm was formed by etching. After being sufficiently dried, the above-described exemplified compound (V-1) purified by sublimation as a luminescent material was vapor-deposited on the surface of the hole transport layer in the same manner as in Example 1, and a 0.065 μm-thick luminescence having carrier transport ability was obtained. A layer was formed. Further, a Mg-Ag alloy was vapor-deposited on the surface of the light emitting layer 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 manufactured organic EL device is 0.04 cm. ² Met.
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0140]
(Example 3)
A charge transporting polyether (exemplified compound (19)) solution was applied by a dipping method to the surface of the ITO glass substrate etched and washed in the same manner as in Example 1 to obtain a thickness of 0.050 μm. A hole transport layer was formed. After sufficiently drying, the sublimated and purified example compound (V-1) as a light emitting material was deposited on the surface of the hole transport layer in the same manner as in Example 1 to form a light emitting layer having a thickness of 0.065 μm. Next, on the surface of the light emitting layer, the exemplified compound (VIII-1) was vacuumed to 1.33 × 10 ^-3 Vacuum deposition was performed under the condition of Pa or less and a boat temperature of 200 ° C. to form an electron transport layer having a thickness of 0.030 μm. Thereafter, a Mg-Ag alloy was deposited on the surface of the electron transport layer by co-evaporation to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to intersect the ITO electrode. The effective area of the formed organic electroluminescent device is 0.04 cm. ² Met.
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0141]
(Example 4)
An organic EL device was produced in the same manner as in Example 1, except that Exemplified Compound (24) was used instead of Exemplified Compound (5).
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0142]
(Example 5)
An organic EL device was produced in the same manner as in Example 2, except that Exemplified Compound (28) was used instead of Exemplified Compound (13).
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0143]
(Example 6)
An organic EL device was produced in the same manner as in Example 3, except that Exemplified Compound (43) was used instead of Exemplified Compound (19).
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0144]
(Example 7)
An organic EL device was produced in the same manner as in Example 1, except that Exemplified Compound (57) was used instead of Exemplified Compound (5).
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0145]
(Example 8)
An organic EL device was produced in the same manner as in Example 1, except that Exemplified Compound (73) was used instead of Exemplified Compound (5).
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0146]
(Example 9)
2 parts by mass of Exemplified Compound (5), 0.1 part by mass of the compound (VII-1) as a light emitting material, and 1 part by mass of the compound (VI) as an electron transporting material were mixed with 10% by mass of dichloroethane. A solution was prepared and filtered through a 0.1 μm PTFE filter. Using this solution, a strip-shaped ITO electrode having a width of 2 mm was etched and applied to the surface of the glass substrate formed by etching to form a light-emitting layer having a carrier transporting ability with a thickness of about 0.15 μm. After drying sufficiently, a Mg-Ag alloy was co-evaporated on the surface of the light emitting layer having the carrier transporting ability 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 manufactured organic EL device is 0.04 cm. ² Met.
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0147]
(Comparative Example 1)
In Example 2, the compound represented by the general formula (IX-1) was used as the hole transporting layer, with a degree of vacuum of 1.33 × 10 ^-3 An organic EL device was produced in the same manner as in Example 2, except that the film was formed by vacuum evaporation under the conditions of Pa or lower and a boat temperature of 200 ° C.
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0148]
(Comparative Example 2)
2 parts by mass of polyvinyl carbazole (PVK) as a charge transporting polymer, 0.1 part by mass of the exemplified compound (V-1) as a light emitting material, and 1 part by mass of the compound (VI) as an electron transporting material, A 10% by mass 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 the surface of 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 co-evaporated on the surface of the hole transport layer to form a back electrode having a width of 2 mm and a thickness of 0.15 μm so as to intersect with the ITO electrode. The effective area of the manufactured organic EL device is 0.04 cm. ² Met.
The same evaluation as in Example 1 was performed for the above organic EL element. The results are shown in Table 21.
[0149]
[Table 21]

[0150]
As shown in the above examples, the organic EL device of the present invention exhibits high maximum luminance despite the low drive current density, and particularly in Examples 2, 5, and 6, 900 cd / m 2. ² The above maximum brightness was obtained. On the other hand, in the organic EL device of the comparative example, sufficient maximum luminance and device life could not be obtained.
[0151]
【The invention's effect】
The charge-transporting polyether comprising a repeating structural unit containing at least one selected from the structures represented by formulas (I-1) and (I-2) as a partial structure is suitable for an organic EL device. Since the organic EL device of the present invention formed using such a thin film can have a good thin film by spin coating, dipping, etc. Since a sufficiently high luminance is exhibited and the film thickness can be set relatively thick, there are few defects such as pinholes, the area can be easily increased, and excellent durability is provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing one example of a stacked organic EL device of the present invention.
FIG. 2 is a schematic cross-sectional view showing another example of the stacked organic EL device of the present invention.
FIG. 3 is a schematic sectional view showing another example of the organic EL device of the present invention.
FIG. 4 is a schematic cross-sectional view showing another example of the stacked organic EL 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 carrier transport ability
7 Back electrode

Claims (18)

An electroluminescent device comprising one or more 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, wherein at least one of the organic compound layers has the following structure. An organic material comprising at least one kind of charge transporting polyether comprising a repeating unit containing at least one kind selected from the structures represented by formulas (I-1) and (I-2) as a partial structure. Electroluminescent device.

[In general formulas (I-1) and (I-2), X represents a substituted or unsubstituted divalent aromatic group. 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 k represents 0 or 1. R ₁ represents a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms or a substituted or unsubstituted aromatic group; R ₂ represents a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, Represents an alkoxy group, a cyano group, a halogen atom, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group represented by Formulas 1 to 4. ] The organic compound layer includes at least a light emitting layer having a carrier transporting ability and an electron transporting layer, and the light emitting layer has at least one selected from the structures 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 charge transporting polyether comprising a repeating unit containing a seed 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 the light emitting layer is at least one selected from the structures 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 charge transporting polyether comprising a repeating unit containing as a partial structure. The organic compound layer includes at least a light emitting layer having a carrier transporting ability, and the light emitting layer has a partial structure of at least one selected from the structures 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 charge transporting polyether comprising a repeating unit containing: The organic compound layer includes at least a hole transporting layer and a light emitting layer having a carrier transporting ability, and at least one of the light emitting layer and the hole transporting layer has the general formula (I-1) or (I-2). 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 selected from the following structures as a partial structure. The organic electroluminescent device according to claim 2, wherein the light emitting layer includes a charge transporting material. The organic electroluminescent device according to claim 3, wherein the light emitting layer includes a charge transporting material. The organic electroluminescent device according to claim 4, wherein the light emitting layer includes a charge transporting material. The organic electroluminescent device according to claim 5, wherein the light emitting layer includes a charge transporting material. The organic electroluminescent device according to claim 1, wherein the charge transporting polyether is a polyether represented by the following general formula (II).

[Wherein, A represents at least one selected from the structures represented by formulas (I-1) and (I-2) above, and R represents a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, Alternatively, it represents a substituted or unsubstituted aralkyl group, and p represents an integer of 5 to 5000. ] The organic electroluminescent device according to claim 2, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 3, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 4, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 5, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 6, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 7, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 8, wherein the charge transporting polyether is a polyether represented by the general formula (II). The organic electroluminescent device according to claim 9, wherein the charge transporting polyether is a polyether represented by the general formula (II).

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