JP2004006271A - Charge transport method and charge transport device using liquid crystal molecules having long linear conjugated structure - Google Patents

Abstract

An object of the present invention is to provide a charge transport method and a charge transport element which can exhibit excellent charge transport ability without photoexcitation using a liquid crystal compound.
The liquid crystal compound has a smectic phase as a liquid crystal phase containing at least one selected from a liquid crystal compound having a long linear conjugated structure or a liquid crystal compound having a long linear conjugated structure derived therefrom. A voltage is applied to the liquid crystal material in a liquid crystal state of a smectic phase, or a liquid crystal compound having a long linear conjugated structure or a liquid crystal compound derived from the compound having a long linear conjugated structure. A charge transport method comprising applying a voltage to a liquid crystalline material having a smectic phase as a liquid crystal phase containing at least one kind in a solid state generated by a phase transition from the smectic phase.
[Selection diagram] None

Description

下記一般式（２）
【化１２】

下記一般式（３）
【化１３】

下記一般式（４）
【化１４】

下記一般式（５）
【化１５】

下記一般式（６）
【化１６】

又は、下記一般式（７）
【化１７】

（一般式（１）〜（７）の式中のＲ^１又はＲ^２は、直鎖状又は分岐状のアルキル基、アルコキシ基、又は下記一般式（８）
【化１８】

｛式中、Ｒ^３は水素原子又はメチル基、Ｂは−（ＣＨ_２）_ｍ−、−（ＣＨ_２）_ｍ−Ｏ−、−ＣＯ−Ｏ−（ＣＨ_２）_ｍ−、−ＣＯ−Ｏ−（ＣＨ_２）_ｍ−Ｏ−、−Ｃ_６Ｈ_４−ＣＨ_２−Ｏ−、−ＣＯ−を示す。｝を表す。Ａは下記一般式（９）〜（１３）
【化１９】

を示す。Ｒ^１とＲ^２は同一の基であっても異なる基であってもよい。）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくも１種を含有する液晶相としてスメクチック相を有する液晶性材料をスメクチック相の液晶状態で電圧を印加することを特徴とする電荷輸送方法を提供する。
【００１０】
また、本発明の第２の発明は、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくも１種を含有する液晶相としてスメクチック相を有する液晶性材料にスメクチック相からの相転移で生じる固体状態で電圧を印加することを特徴とする電荷輸送方法を提供する。
【００１１】
また、本発明の第３の発明は、一対の電極を設けた基板間に前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくも１種を含有する液晶相としてスメクチック相を有する液晶性材料にスメクチック相の液晶状態で電圧を印加し液晶層をとおして電荷を輸送する手段を有することを特徴とする電荷輸送素子を提供する。
【００１２】
また、本発明の第４の発明は、一対の電極を設けた基板間に前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくも１種を含有する液晶相としてスメクチック相を有する液晶性材料にスメクチック相からの相転移で生じる固体状態で電圧を印加し電荷を輸送する手段を有することを特徴とする電荷輸送素子を提供する。
【００１３】
【発明の実施の形態】
以下、本発明を詳細に説明する。
本発明に係る第一の発明の電荷輸送方法は、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくも１種を含有する液晶相としてスメクチック相を有する液晶性材料にスメクチック相の液晶状態で電圧を印加することを特徴とし、光励起しなくとも電圧の印加のみで高い電荷輸送能を発現する。
【００１４】
前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物の式中のＲ^１又はＲ^２は、直鎖状又は分岐状のアルキル基、アルコキシ基、又は前記一般式（８）で表される不飽和結合を有する基を示す。アルキル基としては、炭素数１〜１８であり、具体的にはメチル基、エチル基、ブチル基、ペンチル基、ヘキシル基、オクチル基、ドデシル基、ペンタデシル基、オクタデシル基等が挙げられ、この中炭素数６〜１８のアルキル基が特に好ましい。また、前記アルキル基が一般式；ＣＨ_３−（ＣＨ_２）_ｎ−ＣＨ（ＣＨ_３）−（ＣＨ_２）_ｍ−ＣＨ_２−（式中、ｎは０〜７、ｍは０〜７）で表される分岐状のアルキル基であると各種溶媒への溶解性を向上させることができる。
また、前記アルコキシ基としては、一般式；Ｃ_ｎＨ_２ｎ＋１Ｏで表される式中のｎが１〜２０、好ましくは６〜１８である。
また、前記一般式（８）で表される不飽和結合を有する基の式中のＲ^３は水素原子又はメチル基を示し、Ｂは、−（ＣＨ_２）_ｍ−、−（ＣＨ_２）_ｍ−Ｏ−、−ＣＯ−Ｏ−（ＣＨ_２）_ｍ−、−ＣＯ−Ｏ−（ＣＨ_２）_ｍ−Ｏ−、−Ｃ_６Ｈ_４−Ｏ−、−ＣＯ−を示し、ｍは１〜１８、好ましくは６〜１４のものが特に好ましい。
また、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物の式中のＲ^１とＲ^２は同一の基であっても異なる基であってもよい。
【００１５】
前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物の式中のＡは、前記一般式（９）〜（１３）で表される基である。
【００１６】
また、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物の式中のｎは１〜５、好ましくは１〜３であり、これらの液晶性化合物は、液晶状態でスメクチック相を有する化合物である。
【００１７】
より具体的な好ましい化合物として下記一般式（１５）〜（４９）のものを例示することができる。
【化２０】

【化２１】

【化２２】

【化２３】

【化２４】

（式中、Ｒ^１及びＲ^２は前記と同義。ｎは１〜５の整数を示す。）
【００１８】
本発明において、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物は、シス体又はトランス体或いはシス体とトランス体の混合物であってもよい。また、本発明において前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物中、式中のＲ^１又は／及びＲ^２に不飽和結合を持つものは、高分子化可能である面で好ましい。特に好ましい化合物としては、下記一般式（１４）
【化２５】

で表されるベンゼン誘導体液晶性化合物が特に好ましい。このベンゼン誘導体の式中、Ｒ^４は水素原子、メチル基を示し、Ｚはアルキレン基、−ＣＯ−Ｏ−（ＣＨ_２）_ｎ−、−Ｃ_６Ｈ_４−ＣＨ_２−、−ＣＯ−を示す。アルキレン基は直鎖状又は分岐状のいずれであってもよい。このアルキレン基としては、具体的には炭素数１〜１８のものが好ましく、例えば、メチレン基、エチレン基、トリメチレン基、テトラメチレン基、ペンタメチレン基、エチルエチレン基、プロピレン基、ブチレン基、ヘキシレン基、オクタデシレン基、ノニレン基、デシレン基、ドデシレン基等が挙げられ、この中、炭素数６〜１４のアルキレン基が特に好ましい。また、−ＣＯ−Ｏ−（ＣＨ_２）_ｎ−のｎは１〜１８、好ましくは６〜１４のものが特に好ましい。
【００１９】
本発明において、前記一般式（１４）で表されるベンゼン誘導体液晶性化合物は、新規化合物であり、該化合物は立体配座としてシス体又はトランス体或いはシス体とトランス体の混合物であってもよい。
【００２０】
前記一般式（１４）で表されるベンゼン誘導体液晶性化合物は、下記の第一〜第二工程を実施することにより製造することができる。
＜第一工程＞
第一工程は、下記反応式（１）
【化２６】

（式中、Ｒ^４及びＺは前記と同義。Ｘ^１はハロゲン原子を表す。）で示される反応により、前記一般式（５２）で示されるベンズアルデヒド誘導体を製造する工程である。
【００２１】
第一工程で用いる第１の原料の一般式（５０）で表される４−ヒドロキシベンズアルデヒドは特に制限はなく市販のものを用いることができる。
【００２２】
第一工程で用いる第２の原料の一般式（５１）で表されるハロゲン化物の式中のＲ^４及びＺは、前記一般式（１４）で表されるベンゼン誘導体のＲ^４及びＺに相当する基であり、Ｒ^４は水素原子又はメチル基を示し、Ｚはアルキレン基、−ＣＯ−Ｏ−（ＣＨ_２）_ｎ−、−Ｃ_６Ｈ_４−ＣＨ_２−、−ＣＯ−を示す。アルキレン基は直鎖状又は分岐状のいずれであってもよい。このアルキレン基としては、具体的には炭素数１〜１８のものが好ましく、例えば、メチレン基、エチレン基、トリメチレン基、テトラメチレン基、ペンタメチレン基、エチルエチレン基、プロピレン基、ブチレン基、ヘキシレン基、オクタデシレン基、ノニレン基、デシレン基、ドデシレン基等が挙げられ、この中、炭素数６〜１４のアルキレン基が特に好ましい。
また、−ＣＯ−Ｏ−（ＣＨ_２）_ｎ−のｎは１〜１８、好ましくは６〜１４のものが特に好ましい。
式中のＸ^１は、塩素、臭素、ヨウ素等のハロゲン原子であり、反応性の面で特に臭素原子が好ましい。
【００２３】
第２の原料の一般式（５１）で表されるハロゲン化物は、公知の方法を用いて製造することができ、その一例を示せば、下記反応式（２）
【化２７】

（式中、Ｒ^４、Ｚ及びＸ^１は前記と同義。）で表される反応により、アルコール類（化合物（５３））と、ハロゲン化燐（化合物（５４））とを等モルで、ピリジン等の塩基の存在下にベンゼン等の溶媒中で２０℃で１８時間程度反応させることにより容易に目的とするハロゲン化物（化合物（５１））を製造することができる。なお、かかる反応は、フェノチアジン等の重合禁止剤の存在下に反応を行うことが好ましい。
【００２４】
第一工程の反応は、前記一般式（５０）で表される４−ヒドロキシベンズアルデヒドと前記一般式（５１）で表されるハロゲン化物とを塩基の存在下に溶媒中で反応させる。
【００２５】
前記一般式（５１）で表されるハロゲン化物の添加量は、前記一般式（５０）で表される４−ヒドロキシベンズアルデヒドに対して１倍モル以上、好ましくは１．５〜２．０倍モルである。
【００２６】
用いることができる塩基としては、水酸化ナトリウム、炭酸ナトリウム、炭酸水素ナトリウム、水酸化カリウム、炭酸カリウム、炭酸水素カリウム、水酸化カルシウム、炭酸カルシウム、水酸化バリウム、水酸化カルシウム等の無機塩基類、トリメチルアミン、Ｎ，Ｎ−ジメチルシクロヘキシルアミン、Ｎ，Ｎ−ジエチルシクロヘキシルアミン、Ｎ，Ｎ−ジメチルベンジルアミン、Ｎ，Ｎ’−ジメチルピペラジン、Ｎ，Ｎ−ジメチルアニリン、Ｎ，Ｎ−ジエチルアニリン，Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチル−１，３−プロパンジアミン、ピリジン、α−ピコリン、β−ピコリン、γ−ピコリン、４−エチルモルホリン、トリエチレンジアミン、１，３−ジアザビシクロ［５，４，０］ウンデセン、１，８−ジアザビシクロ［５，４，０］−７−ウンデセン、Ｎ−エチルピペリジン、キノリン、イソキノリン、Ｎ，Ｎ−ジメチルピペラジン、Ｎ，Ｎ−ジエチルピペラジン、キナルジン、２−エチルピリジン、４−エチルピリジン、３，５−ルチジン、２，６−ルチジン、４−メチルモルホリン、２，４，６−コリジン等の有機塩基類、ピリジル基やジメチルアミノベンジル基を有するイオン交換樹脂、ナトリウム・メトキシド、カリウム・メトキシド、ナトリウム・エトキシド、カリウム・エトキシド等のアルコキシド等が挙げられ、これらは１種又は２種以上で用いられるが、特にこれらに限定されるものではない。
これら塩基の添加量は、前記一般式（５０）で表される４−ヒドロキシベンズアルデヒドに対して通常等モルで十分である。
【００２７】
反応溶媒としては、例えば、ジオキサン、テトラヒドロフラン、ジブチルエーテル等のエーテル類、アセトニトリル、プロピオニトリル等のニトリル類、メタノール、エタノール等のアルコール類、ジメチルホルムアミド、アセトン、水等の１種又は２種以上で用いることができる。
【００２８】
反応条件としては、反応温度が０〜１００℃、好ましくは２０〜５０℃であり、反応時間が０．５〜５０時間、好ましくは１０〜３０時間で反応を行う。
【００２９】
反応終了後、酸で洗浄、抽出、洗浄、脱水、再結晶、カラムクロマトグラフィー等の諸操作を得て前記一般式（５２）で示されるベンズアルデヒド誘導体を得る。
【００３０】
＜第二工程＞
第二工程は、下記反応式（３）
【化２８】

（式中、Ｒ^４及びＺは前記と同義。Ｘ^２はハロゲン原子を示す。）で表される反応により、前記一般式（１４）で表されるベンゼン誘導体を得る工程である。
【００３１】
前記一般式（５５）で表されるｐ−キシレンビス−（トリフェニルホスホニウムハロゲン）の式中のＸ^２は、塩素、臭素、ヨウ素等のハロゲン原子を示し、この中、臭素が反応性の面で特に好ましい。これらのｐ−キシレンビス−（トリフェニルホスホニウムハロゲン）は市販品を用いることができる。
【００３２】
第二工程の反応は、前記一般式（５２）で表されるベンゾアルデヒド誘導体と前記一般式（５５）で表されるｐ−キシレンビス−（トリフェニルホスホニウムハロゲン）とを塩基の存在下に溶媒中で反応させる。
【００３３】
前記一般式（５２）で表されるベンズアルデヒド誘導体の添加量は　前記一般式（５５）で表されるｐ−キシレンビス−（トリフェニルホスホニウムハロゲン）に対して２〜４倍モル、好ましくは２〜２．５倍モルである。
【００３４】
第二工程で用いることができる塩基としては、特に制限はないが、例えば、水素化ナトリウム等の金属水素化物、トリメチルアミン、トリエチルアミン等のアミン類、水酸化カリウム、水酸化ナトリウム等の水酸化アルカリ、ナトリウム・メトキシド、カリウム・メトキシド、ナトリウム・エトキシド、カリウム・エトキシド等のアルコキシド、ピペリジン、ピリジン、カリウムクレゾラート、アルキルリチウム等が挙げられ、これらは１種又は２種以上で用いられる。
これらの塩基の添加量は、前記一般式（５５）で表されるｐ−キシレンビス−（トリフェニルホスホニウムハロゲン）に対して１〜５倍モル、好ましくは３．５〜４．５倍モルである。
【００３５】
反応溶媒としては、例えば、ジオキサン、テトラヒドロフラン、ジブチルエーテル等のエーテル類、アセトニトリル、プロピオニトリル等のニトリル類、メタノール、エタノール等のアルコール類、ジメチルホルムアミド、アセトン等の１種又は２種以上で用いることができる。
【００３６】
反応条件としては、反応温度が０〜１００℃、好ましくは２０〜５０℃であり、反応時間が０．５〜５０時間、好ましくは５〜３０時間で反応を行う。
【００３７】
反応終了後、濾過、所望により洗浄後、乾燥して前記一般式（１４）で示されるベンゼン誘導体を得る。
【００３８】
かくして得られる前記一般式（１４）で表されるベンゼン誘導体液晶性化合物は、新規化合物であり、また、本発明において、所望により得られる前記一般式（１４）で示されるベンゼン誘導体液晶性化合物を、更にヨウ素の存在下に溶媒中で加熱処理することができる。
この加熱処理により前記一般式（１４）で示されるベンゼン誘導体液晶性化合物は選択的にトランス体とすることができる。
この場合、ヨウ素の添加量は前記一般式（１４）で示されるベンゼン誘導体液晶性化合物に対して０．００１〜０．１倍モル、好ましくは０．００５〜０．０１倍モルであり、加熱処理温度は１００〜１８０℃、好ましくは１３０〜１５０℃である。また、用いることができる溶媒として、例えば、ベンゼン、トルエン、ｏ−キシレン、ｍ−キシレン、ｐ−キシレン、クロロベンゼン、ｏ−ジクロロベンゼン、ｍ−ジクロロベンゼン、ｐ−ジクロロベンゼン等が挙げられ、これらの溶媒は１種又は２種以上で用いることができる。
【００３９】
前記一般式（１４）で表されるベンゼン誘導体は、液晶性を示し、青色発光を有し、電荷輸送能を有する化合物であり、例えば、電荷輸送性を利用した光センサ、有機エレクトロルミネッンス素子（ＥＬ素子）、光導電体、空間変調素子、薄膜トランジスター、電子写真感光体の電荷輸送物質、ホトリソグラフティブ、太陽電池、非線形光学材料、有機半導体コンデンサー、その他のセンサー等の材料として用いることができる。
【００４０】
本発明の前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくとも１種を含有する液晶性材料は電荷輸送材料として好適に用いることができる。
【００４１】
ここで前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物から誘導される長い直線的共役系構造部分を持つ液晶性化合物とは末端に不飽和結合を有するものは、そのホモ重合体、共重合体、架橋剤により架橋されている高分子量の化合物、或いはヒドロシリル基を有する高分子化合物に付加反応させて得られる高分子量の化合物をいう（以下、「重合体」という）。
【００４２】
重合体は、共重合成分として、アクリル酸、メタクリル酸又はスチレン等から誘導される繰り返し単位を有していてもよい。また、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物の式中のＲ^２の異なるものの混合物の共重合体であってもよい。共重合体の場合、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物の反応残基が、共重合体中５０モル％以上、好ましくは７０モル％以上、さらに好ましくは８０モル％以上である。
重合体の分子量は、数平均分子量が１０００〜数千万の範囲、好ましくは数万〜数百万の範囲である。
重合体は以下の方法で製造することができる。例えば前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物のホモ重合体、共重合体、或いは架橋剤により架橋されている高分子量の化合物を製造するには、所望のモノマー又は所望のモノマーと架橋剤とを重合開始剤の存在下に、溶液重合法、懸濁重合法、乳化重合法、バルク重合法等のラジカル重合法により重合反応を行うことにより製造することができる。
【００４３】
また、ヒドロシリル基を有する高分子化合物に前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を付加反応させて高分子量の化合物を製造するには、ヒドロシリル基を有する高分子化合物と前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物とを塩化白金酸、塩化白金酸のアルコール溶液、白金とオレフィン錯体の錯体、ロジウムとカルボニルの錯体等のロジウム系触媒等の存在下に反応を行うことにより製造することができる。
【００４４】
本発明の電荷輸送方法において、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を単独又はそれらを２種以上用いた混合物で用いことができるのは勿論であるが、該液晶性化合物を含有する組成物、前記重合体、又は前記重合体を含有する組成物からなる液晶性材料は電荷輸送材料として好適に用いることができる。
【００４５】
前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を含有する組成物は、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を少なくとも３０重量％以上、好ましくは５０重量％以上、更に好ましくは９０重量％以上含有し、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物に起因するスメクチック相の液晶状態を示すものである。
かかる組成物中の他の成分としては、例えば、他の液晶性化合物、他の長い直線的共役系を有する両端がアルキル基またはアルコキシ基である化合物を１種又は２種以上含有させて用いることができ、他の成分の長い直線的共役系を有する両端がアルキル基またはアルコキシ基である化合物は液晶性化合物であってもそうでなくてもよい。また、他の長い直線的共役系を有する両端がアルキル基またはアルコキシ基である化合物は、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物であってもよい。
前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を含有する組成物は、以下のように調製することができる。即ち、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物と所望の上記成分を溶媒に溶解した後、溶媒を加熱、減圧等で除去するか、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物と所望の上記成分を混合し、加熱溶融するか、又はスパッタリング、真空蒸着等を行うことにより調製することができる。
【００４６】
また、前記重合体を含有する組成物は、前記重合体を、少なくとも３０重量％以上、好ましくは５０重量％以上、さらに好ましくは８０重量％以上含有し、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物に起因するスメクチック相の液晶状態を示すものである。
かかる組成物中の他の成分としては、例えば、他の液晶性化合物、他の長い直線的共役系を有する両端がアルキル基またはアルコキシ基である化合物を１種又は２種以上含有させて用いることができ、他の成分の長い直線的共役系を有する両端がアルキル基またはアルコキシ基である化合物は液晶性化合物であってもそうでなくてもよい。また、他の長い直線的共役系を有する両端がアルキル基またはアルコキシ基である化合物は、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物であってもよい。
この重合体組成物は、以下のように調製することができる。即ち、前記重合体と所望の上記成分を溶媒に溶解した後、溶媒を加熱、減圧等で除去するか、前記重合体と所望の上記成分を混合し、加熱溶融するか、又はスパッタリング、真空蒸着等を行うことにより調製することができる。
【００４７】
本発明に係る第一の発明の電荷輸送方法は、上記した長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくとも１種を含有する液晶相としてスメクチック相を有する液晶性材料を所定の温度でスメクチック相とし、このスメクチック相の液晶状態で電圧を印加し電荷の輸送を行うものである。
この場合、スメクチック相は、Ａ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈの何れの相の状態であってもよい。
【００４８】
本発明に係る第二の発明の電荷輸送方法は、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくとも１種を含有する液晶相としてスメクチック相を有する液晶性材料をスメクチック相からの相転移で生じる固体状態、具体的に結晶相、ガラス状態、不定形固体で電圧を印加することを特徴とし、光励起しなくとも電圧の印加のみで高い電荷輸送能を発現する。
【００４９】
この第二の発明の電荷輸送方法に用いることができる液晶性材料は、第一の発明の電荷輸送方法と同様に前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を単独又はそれらを２種以上用いた混合物、該液晶性化合物を含有する組成物、前記重合体、又は前記重合体を含有する組成物が挙げられる。
【００５０】
また、固体状態で用いる場合には、前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を単独又はそれらを２種以上用いた混合物、前記した該液晶性化合物を含有する組成物、前記重合体、又は前記重合体を含有する組成物を含有した液晶性材料を一旦加温してスメクチック相とし、この状態から降温を行うことによりスメクチック相の分子配向を維持した固体状態とすることができる。
【００５１】
また、この降温を除々に行うと、よりスメクチック相の分子配向を維持できることから急冷を行ったものより優れた電荷輸送能を発現させることができる。
【００５２】
次いで、本発明の第三と第四の発明の電荷輸送素子について説明する。
本発明の電荷輸送素子は、一対の電極を設けた基板間に前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物を単独又はそれらを２種以上用いた混合物、前記した該液晶性化合物を含有する組成物、前記重合体、又は前記重合体を含有する組成物を含有した液晶相としてスメクチック相を有する液晶性材料（以下、「液晶性材料」と略記する。）を用いた液晶層を有し、かつ該液晶性材料をスメクチック相の液晶状態で電圧を印加し、液晶層をとおして電荷を輸送する手段（以下、「１の電荷輸送素子」と呼ぶ。）、又は、一対の電極を設けた基板間に前記液晶性材料を用いた液晶層を有し、かつ該電荷輸送材料をスメクチック相からの相転移で生じる固体状態で電圧を印加し液晶層をとおして電荷を輸送する手段（以下、２の電荷輸送素子）と呼ぶ。）を備えた電荷輸送素子である。
【００５３】
図１は前記１の電荷輸送素子の一実施態様を示す概略図である。図１において、本発明の電荷輸送素子は、２枚のガラス基板１ａ、１ｂの表面に、各々ＩＴＯ等の透明電極からなる電極２ａ、２ｂを設け、該電極を設けた一対の基板をスペ−サー４を介してセル間隔を一定にたもって接着剤で貼り合わせてセルを作成し、該セル内に前記液晶性材料を注入して液晶層３に電極間に設け、該電極２ａ、２ｂには前記液晶性材料のスメクチック相の液晶状態で電圧を印加すると、液晶層を通して高い電流密度が得られ、電荷の輸送を行うことができる。
【００５４】
図２は前記２の電荷輸送素子の一実施態様を示す概略図である。図２において、本発明の電荷輸送素子は、２枚のガラス基板１ａ、１ｂの表面に、各々ＩＴＯ等の透明電極からなる電極２ａ、２ｂを設け、該電極を設けた一対の基板をスペーサー４を介してセル間隔を一定にたもって接着剤で貼り合わせてセルを作成し、該セル内に前記液晶性材料を注入して液晶層１３に電極間に設け、該電極２ａ、２ｂには前記液晶性材料のスメクチック相の相転移で生じる固体状態で電圧を印加する電圧印加手段５を接続してなるものである。電圧印加手段５及び液晶相の温度調節手段（不図示）等からなる電荷輸送手段により液晶層１３の電荷輸送材料にスメクチック相からの相転移で生じる固体状態で電圧を印加すると、液晶層をとおして高い電流密度が得られ、電荷の輸送を行うことができる。
【００５５】
本発明の電荷輸送材料として用いる前記一般式（１）〜（７）で表される長い直線的共役系構造部分を持つ液晶性化合物は、スメクチック相の液晶状態、或いはスメクチック相からの降温により相転移で生じる固体状態のスメクチック相の層状配列を持った分子配向を利用することにより、該液晶性化合物の長い共役π電子系の重なりが密になり５００μＡ／ｃｍ^２オーダ以上、好ましくは１ミリＡ／ｃｍ^２オーダ以上の電流密度で電荷の輸送を可能し、この電荷輸送性を利用して光センサ、有機エレクトロルミネッンス素子（ＥＬ素子）、光導電体、空間変調素子、薄膜トランジスター、電子写真感光体の電荷輸送物質、ホトリソグラフティブ、太陽電池、非線形光学材料、有機半導体コンデンサー、その他のセンサー等の材料の電荷輸送方法として好適に用いることができる。
【００５６】
例えば、本発明の液晶性材料を、有機エレクトロルミネッセンス素子（ＥＬ素子）に用いる場合には、必要により他の発光材料を添加したものを発光層として２枚の電極（少なくとも１枚はＩＴＯのような透明電極）に挟むことにより作成することができる。また、多層型有機発光素子の場合は、本発明の電荷輸送材料をホール輸送層、電子輸送層あるいは発光層として用いることもできる。また、光センサーの場合は、本発明の液晶性材料を２枚の電極（少なくとも１枚は透明）に挟持させることにより、光照射による電流変化を検出することができる。電子写真感光体又は画像記憶素子として用いる場合には、基板又は電極上に電荷発生層と本発明の電荷輸送層を積層することにより作成することができる。
【００５７】
【実施例】
以下、本発明を実施例により詳細に説明するが本発明はこれらに限定されるものではない。
実施例１
＜第一工程＞
下記反応式（４）
【化２９】

に従って、ｐ−（９−デセノキシ）−ベンズアルデヒド（化合物（５７））を合成した。
水酸化カリウム１．１２ｇ（０．０２モル）を溶解したエタノール溶液５０ｍｌを４−ヒドロキシベンズアルデヒド（化合物（５０））２．４４ｇ（０．０２モル）をエタノール３０ｍｌに溶解した溶液に加えた。これを攪拌しエバポレーターでエタノールを減圧除去する。残さをＤＭＦ５０ｍｌに溶解させ、１０−ブロモ−１−デセン（化合物（５６））６．５７ｇ（０．０３モル）を溶解したＤＭＦ溶液１０ｍｌを滴下する。窒素雰囲気下、７０℃で１５時間反応を行った。反応終了後、室温まで冷却し、氷希塩酸中に反応液を投入した。次いで、これにジエチルエーテルを加え、抽出を行った後、無水硫酸ナトリウムで一晩脱水した後、無水硫酸ナトリウムを濾過により除去し、エバポレーターでジエチルエーテルを除去した。除去したジエチルエーテルを溶媒にカラムクロマトグラフィーにより分離し、乾燥後、薄黄色液体の目的物であるｐ−（９−デセノキシ）−ベンズアルデヒド（化合物（５７））３．６２ｇ（収率６９．５％）を得た。
＜同定データ＞
・^１Ｈ−ＮＭＲ（δ、ＣＤＣｌ_３）：
０．８〜２．０（ｍ，１４Ｈ，−（ＣＨ_２）_７−）、４．０（ｔ，２Ｈ，−Ｏ−ＣＨ_２−）、４．９〜５．１（ｄ，２Ｈ，−Ｃ＝ＣＨ_２）、５．３〜６．２（ｍ，１Ｈ，−ＣＨ＝Ｃ）、７．０，７，９（ｄ，４Ｈ，ａｒｏｍａｔｉｃ）、１０（ｓ，１Ｈ，−ＣＨＯ）
【００５８】
＜第二工程＞
第二工程は、下記反応式（５）
【化３０】

に従って、ベンゼン誘導体（化合物（５９））を合成した。
第一工程で得られたｐ−（９−デセニキシ）−ベンズアルデヒド（化合物（５７））２．６０ｇ（０．０１モル）とｐ−キシレンビス−（トリフェニルホスホニウムブロミド）（化合物（５８）、東京化成社製）３．９３ｇ（０．００５モル）を溶解したエタノール溶液５０ｍｌに０．４モルのナトリウムエトキシド５０ｍｌを滴下し室温で３０分攪拌した後、５０℃で１０時間反応させる。反応液を濾過し、沈澱を６０％エタノール水溶液、ヘキサンで洗浄する。これを乾燥して淡黄色固体の目的物であるベンゼン誘導体（化合物（５９））１．１０ｇ（収率１８．６％）を得た。
＜同定データ＞
^１Ｈ−ＮＭＲ（δ、ＣＤＣｌ_３）：
１．２〜１．５（ｍ，１６Ｈ），１．６〜１．７（ｍ，４Ｈ），１．７〜１．８（ｍ，４Ｈ），２．０〜２．１（ｍ，４Ｈ），３．９〜４．０（ｔ，４Ｈ），４．９〜５．１（ｄ，４Ｈ），５．７〜５．９（ｍ，２Ｈ），６．８（ｄ，４Ｈ），６．９〜７．１（ｍ，４Ｈ），７．２〜７．５（ｍ，８Ｈ）
ＩＲ（ｃｍ^−１，ＫＢｒ）
７２１（ｐ−ｐｈ面外変角），９６８（ｔ−Ｃ＝Ｃ−面外変角），１１１０〜１２５３（Ｃ−Ｏ−Ｃ伸縮），１４６５〜１５７３（ｐｈ骨格振動），１６４１（ＣＨ_２＝ＣＨ−伸縮），２８５２〜２９２１（脂肪族ＣＨ伸縮）
３０２１〜３０７５（芳香族ＣＨ伸縮）
・ＭＡＳＳ（ＦＡＢ；Ｘｅ）：５９０（Ｍ‐１）
【００５９】
更に、Ｘ線回折分析、偏光顕微鏡による液晶相のｔｅｘｔｕｒｅの観察より下記数１に示す相転移が明らかになった。また、１７０℃で該化合物をＸ線回折分析したときのＸ線回折図を図３に示す。
【００６０】
【数１】

Ｃｙｓｔ；結晶、ＳｍＧ；スメクチックＧ相、ＳｍＢ；スメクチックＢ相、ＳｍＡ；スメクチックＡ相、Ｉｓｏ；等方性液体
【００６１】
また、得られた化合物を励起波長３６８ｎｍで測定した時の蛍光スペクトルを図４に示す。
【００６２】
＜電荷輸送能の評価＞
真空成膜によりＩＴＯ電極を設けた２枚のガラス基板を、それぞれＩＴＯ電極が対向するように、スペーサー粒子によってギャップ（約１５μｍ）を設け、貼り合わせてセルを作成した。
そのセルに実施例１で得られたベンゼン誘導体（化合物（５９））２０ｍｇを２３０℃の条件下にセル中に注入した。
次いで、５Ｖの電圧を印加し、除々に加温し、各温度毎の電流量を測定した。その結果を図５に示す。
また、１３０℃の温度に保持し、各電圧毎の電流量の測定を２回行った。１回目の結果を図６に、２回目の結果を図７に示す。
また、１３０℃から自然冷却により１００℃まで温度を下げ、１００℃で各電圧毎の電流量を測定し、その結果を図８に示す。
また、１３０℃から冷蔵庫で１０分かけて１００℃まで温度を下げ冷却（急冷）後、１００℃で各電圧毎の電流量を測定し、その結果を図８に示す。
また、１３０℃から自然冷却により５０℃まで温度を下げ、５０℃で各電圧毎の電流量を測定し、その結果を図９に示す。
また、１３０℃から冷蔵庫で１０分かけて５０℃まで温度を下げ冷却（急冷）後、５０℃で各電圧毎の電流量を測定し、その結果を図９に示す。
【００６３】
【発明の効果】
上記したとおり、本発明の電荷輸送方法は、特定の構造式を有する長い直線的共役系構造部分を持つ液晶性化合物又はそれから誘導される長い直線的共役系構造部分を持つ液晶性化合物から選ばれる少なくとも１種を含有する液晶相としてスメクチック相を有する液晶性材料をスメクチック相の液晶状態又はスメクチック相の液晶状態からの相転移で生じる固体状態で電圧を印加することにより優れた電荷輸送能を発現し、従来の電荷輸送材料にない５００μＡ／ｃｍ^２オーダ以上、好ましくは１ミリＡ／ｃｍ^２以上の電流密度で電荷の輸送を可能とする。これは導電率で少なくとも１．６×１０^−７ｓ／ｃｍ以上に相当し、この値は半導体領域の値である。
従って、本発明の電荷輸送方法および電荷輸送素子は、電荷輸送性を利用した光センサ、有機エレクトロルミネッンス素子（ＥＬ素子）、光導電体、空間変調素子、薄膜トランジスター、電子写真感光体の電荷輸送物質、ホトリソグラフティブ、太陽電池、非線形光学材料、有機半導体コンデンサー、有機半導体コンデンサー、その他のセンサー等の電荷輸送方法として好適に用いることができる。
【００６４】
【図面の簡単な説明】
【図１】本発明の電荷輸送素子の一実施態様を示す概略図である。
【図２】本発明の電荷輸送素子の一実施態様を示す概略図である。
【図３】実施例１で得られたベンゼン誘導体を１７０℃で測定したときのＸ線回折図。
【図４】実施例１で得られたベンゼン誘導体を励起波長３６８ｎｍで測定した時の蛍光スペクトルを示す図。
【図５】実施例１で得られたベンゼン誘導体に５Ｖの電圧を印加し、除々に加温し、各温度毎の電流量を測定した時の温度と電流量の関係を示す図。
【図６】実施例１で得られたベンゼン誘導体を１３０℃の温度に保持し、電圧と電流量との関係を示す図（１回目）。
【図７】実施例１で得られたベンゼン誘導体を１３０℃の温度に保持し、電圧と電流量との関係を示す図（２回目）。
【図８】実施例１で得られたベンゼン誘導体を１３０℃まで加温し自然冷却により１００℃まで温度を下げ、１００℃での電圧と電流量の関係を示す図及び実施例１で得られたベンゼン誘導体を１３０℃まで加温し急冷により１００℃まで温度を下げ、１００℃での電圧と電流量の関係を示す図。
【図９】実施例１で得られたベンゼン誘導体を１３０℃まで加温し自然冷却により５０℃まで温度を下げ、５０℃での電圧と電流量の関係を示す図及び実施例１で得られたベンゼン誘導体を１３０℃まで加温し急冷により５０℃まで温度を下げ、５０℃での電圧と電流量の関係を示す図。
【００６５】
【符号の説明】
１ａ，１ｂ　ガラス基板
２ａ，２ｂ　電極
４　スペンサー
３，１３　液晶層
５　電圧印加手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical sensor utilizing charge transport properties, an organic electroluminescence element (EL element), a photoconductor, a spatial modulation element, a thin film transistor, a charge transport substance of an electrophotographic photosensitive member, a photolithographic element, and a solar cell. The present invention relates to a charge transport method and a charge transport element using a liquid crystal compound having a long linear conjugated structure, which is useful as a charge transport method for nonlinear optical materials, organic semiconductor capacitors, and other sensors.
[0002]
[Prior art]
In recent years, organic electroluminescent devices using organic materials as hole transporting materials and charge transporting materials constituting electroluminescent devices have been actively studied.
As such charge transport materials, compounds such as anthracene derivatives, anthraquinoline derivatives, imidazole derivatives, styryl derivatives, hydrazone derivatives, triphenylamine compounds, poly-N-vinylcarbazole and oxadiazole have been known. ing.
Liquid crystal compounds are applied to various devices as display materials, and are used, for example, in watches, calculators, televisions, personal computers, mobile phones, and the like. Liquid crystal substances are classified into a thermotropic liquid crystal (temperature transition type liquid crystal) and a lyotropic liquid crystal (concentration transition type liquid crystal) based on a means for giving a phase transition. In terms of molecular arrangement, these liquid crystals are classified into three types: smectic liquid crystals, nematic liquid crystals, and cholesteric liquid crystals. A liquid crystal exhibits optical anisotropy similar to that of an optically uniaxial crystal, which is also referred to as an anisotropic liquid. Orthoscope observation is a normal observation between orthogonal Nicols, and is useful for discriminating the type of liquid crystal and determining the transition temperature of the liquid crystal phase. , A, B, C, D, E, F, and G.
[0003]
Hanna et al. Have proposed a charge transporting material using a liquid crystalline compound having a smectic liquid crystal phase having a charge transporting ability. For example, a liquid crystalline charge transport material having a smectic liquid crystal property and having a reduction potential in a range of -0.3 to -0.6 (Vvs. SEC) with respect to a standard reference electrode (SCE) (see Patent Document 1). ), A liquid crystal compound exhibiting a smectic phase having a self-orienting property, and a liquid crystal charge transporting material in which a predetermined amount of fullerene C70 having a sensitizing action is blended (see Patent Document 2). A liquid crystalline charge transport material-dispersed polymer film contained in a polymer matrix (see Patent Document 3), a liquid crystalline charge transport material containing a mixture containing a smectic liquid crystalline compound (see Patent Document 4), It has a smectic liquid crystal property and an electron mobility or a hole mobility speed of 1 × 10 ^-5 cm ² / V · s or more (see Patent Literature 5). A functional group capable of forming a new bond between molecules or within a molecule and a hole and / or electron charge transporting property in one molecule. A liquid crystal charge transport material containing a smectic liquid crystal compound having a functional group (see Patent Document 6) and the like have been proposed.
[0004]
The smectic liquid crystal compound proposed above is a 6π electron aromatic ring such as a benzene ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a tropolone ring, a naphthalene ring, an azulene ring, a benzofuran ring, an indole ring and an indazole ring. , A benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a 10π-electron aromatic ring such as a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, or a 14π-electron aromatic ring such as a phenanthone ring or anthracene. Is used to transport charges in a smectic A phase liquid crystal state. However, the above-described charge transport method requires photoexcitation, and its conductivity is 10 times without photoexcitation. ^-13 s / cm, 10 ^-11 The value of the insulator region was s / cm.
[0005]
The present inventors have proposed a charge transport method in which a voltage is applied to a liquid crystalline compound having a smectic B phase as a liquid crystal phase in a liquid crystal state of the smectic B phase or a solid state generated by a phase transition of the smectic B phase (see Patent Document 7). .) Proposed.
[0006]
[Patent Document 1]
JP-A-09-316442
[Patent Document 2]
JP-A-11-162648
[Patent Document 3]
JP-A-11-172118
[Patent Document 4]
JP-A-11-199871
[Patent Document 5]
JP-A-10-312711
[Patent Document 6]
JP-A-11-209761
[Patent Document 7]
JP 2001-351786 A
[0007]
[Problems to be solved by the invention]
Further, the present inventors have studied a charge transport method using molecular orientation in a liquid crystal state, and have found that a liquid crystalline compound having a long linear conjugated structure represented by a specific general formula or a liquid crystalline compound derived therefrom. When a voltage is applied to a liquid crystal material containing at least one selected from liquid crystal compounds having a long linear conjugated structure in a liquid crystal state of a smectic phase or a solid state generated by a phase transition from a smectic phase, there is no photoexcitation. In both cases, they have found that they exhibit excellent charge transporting ability, and have completed the present invention.
[0008]
That is, an object of the present invention is to provide a charge transport method and a charge transport element which can exhibit excellent charge transport ability without photoexcitation using a liquid crystal compound.
[0009]
[Means for solving the problem]
Under such circumstances, the first invention of the present invention provides the following general formula (1)
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The following general formula (2)
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The following general formula (3)
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The following general formula (4)
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The following general formula (5)
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The following general formula (6)
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Or, the following general formula (7)
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(R in the formulas (1) to (7) ¹ Or R ² Is a linear or branched alkyl group, an alkoxy group, or the following general formula (8)
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中 where R ³ Is a hydrogen atom or a methyl group, and B is-(CH ₂ ) _m -,-(CH ₂ ) _m -O-, -CO-O- (CH ₂ ) _m -, -CO-O- (CH ₂ ) _m -O-, -C ₆ H ₄ -CH ₂ -O- and -CO- are shown. Represents｝. A represents the following general formulas (9) to (13)
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Is shown. R ¹ And R ² May be the same or different groups. The liquid crystal compound having a long linear conjugated structure represented by the formula (1) or a liquid crystal compound having a long linear conjugated structure derived therefrom has a smectic phase as a liquid crystal phase containing at least one selected from the group. The present invention provides a charge transport method characterized by applying a voltage to a liquid crystalline material having a smectic phase liquid crystal state.
[0010]
The second invention of the present invention relates to a liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) or a long linear conjugated structure derived therefrom. A charge transport method characterized in that a voltage is applied to a liquid crystal material having a smectic phase as a liquid crystal phase containing at least one selected from liquid crystal compounds having a smectic phase in a solid state generated by a phase transition from the smectic phase. I do.
[0011]
A third invention of the present invention is a liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) between substrates provided with a pair of electrodes, or a liquid crystal compound derived therefrom. A voltage is applied to a liquid crystal material having a smectic phase as a liquid crystal phase containing at least one selected from liquid crystal compounds having a long linear conjugated structure portion in a smectic phase liquid crystal state, and a charge is applied through the liquid crystal layer. And a means for transporting the same.
[0012]
A fourth invention of the present invention is a liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) between substrates provided with a pair of electrodes, or a liquid crystal compound derived therefrom. A voltage is applied to a liquid crystal material having a smectic phase as a liquid crystal phase containing at least one selected from a liquid crystal compound having a long linear conjugated structure part in a solid state caused by a phase transition from the smectic phase. And a means for transporting the same.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The charge transport method of the first invention according to the present invention provides a liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) or a long linear conjugated system derived therefrom. It is characterized in that a voltage is applied in a smectic phase liquid crystal state to a liquid crystal material having a smectic phase as a liquid crystal phase containing at least one selected from liquid crystal compounds having a structural part, and voltage is applied without photoexcitation. Alone exhibit high charge transport ability.
[0014]
R in the formula of the liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) ¹ Or R ² Represents a linear or branched alkyl group, an alkoxy group, or a group having an unsaturated bond represented by the general formula (8). The alkyl group has 1 to 18 carbon atoms, and specific examples include a methyl group, an ethyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a pentadecyl group, and an octadecyl group. An alkyl group having 6 to 18 carbon atoms is particularly preferred. Further, the alkyl group has a general formula: CH ₃ − (CH ₂ ) _n -CH (CH ₃ )-(CH ₂ ) _m -CH ₂ -(Where n is 0 to 7, and m is 0 to 7) is a branched alkyl group which can improve solubility in various solvents.
Further, as the alkoxy group, a general formula: C _n H _{2n + 1} N in the formula represented by O is 1-20, preferably 6-18.
In addition, in the group having an unsaturated bond represented by the general formula (8), R ³ Represents a hydrogen atom or a methyl group, and B represents-(CH ₂ ) _m -,-(CH ₂ ) _m -O-, -CO-O- (CH ₂ ) _m -, -CO-O- (CH ₂ ) _m -O-, -C ₆ H ₄ -O- and -CO-, wherein m is 1 to 18, preferably 6 to 14;
In addition, R in the formula of the liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7). ¹ And R ² May be the same or different groups.
[0015]
A in the formula of the liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) is a group represented by the general formulas (9) to (13). .
[0016]
Further, n in the formula of the liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) is 1 to 5, preferably 1 to 3, The compound is a compound having a smectic phase in a liquid crystal state.
[0017]
More specific preferred compounds include those represented by the following formulas (15) to (49).
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(Where R ¹ And R ² Is as defined above. n shows the integer of 1-5. )
[0018]
In the present invention, the liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) may be a cis-form or a trans-form or a mixture of a cis-form and a trans-form. . In the present invention, among the liquid crystalline compounds having a long linear conjugated structure represented by the general formulas (1) to (7), ¹ Or / and R ² Having an unsaturated bond is preferred from the viewpoint that it can be polymerized. Particularly preferred compounds are those represented by the following general formula (14)
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Is particularly preferable. In the formula of this benzene derivative, R ⁴ Represents a hydrogen atom or a methyl group, Z represents an alkylene group, -CO-O- (CH ₂ ) _n -, -C ₆ H ₄ -CH ₂ -, -CO-. The alkylene group may be linear or branched. Specifically, the alkylene group is preferably one having 1 to 18 carbon atoms, for example, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, ethylethylene group, propylene group, butylene group, hexylene. And an octadecylene group, a nonylene group, a decylene group and a dodecylene group. Among them, an alkylene group having 6 to 14 carbon atoms is particularly preferable. Further, -CO-O- (CH ₂ ) _n The n of-is particularly preferably 1 to 18, preferably 6 to 14.
[0019]
In the present invention, the benzene derivative liquid crystal compound represented by the general formula (14) is a novel compound, and the compound may be a cis- or trans-form or a mixture of cis- and trans-forms in conformation. Good.
[0020]
The benzene derivative liquid crystalline compound represented by the general formula (14) can be produced by performing the following first and second steps.
<First step>
The first step is represented by the following reaction formula (1)
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(Where R ⁴ And Z are as defined above. X ¹ Represents a halogen atom. )) To produce a benzaldehyde derivative represented by the general formula (52).
[0021]
The 4-hydroxybenzaldehyde represented by the general formula (50) as the first raw material used in the first step is not particularly limited, and a commercially available one can be used.
[0022]
R in the formula of the halide represented by the general formula (51) of the second raw material used in the first step ⁴ And Z are R of the benzene derivative represented by the general formula (14). ⁴ And a group corresponding to Z, ⁴ Represents a hydrogen atom or a methyl group, Z represents an alkylene group, -CO-O- (CH ₂ ) _n -, -C ₆ H ₄ -CH ₂ -, -CO-. The alkylene group may be linear or branched. Specifically, the alkylene group is preferably one having 1 to 18 carbon atoms, for example, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, ethylethylene group, propylene group, butylene group, hexylene. And an octadecylene group, a nonylene group, a decylene group and a dodecylene group. Among them, an alkylene group having 6 to 14 carbon atoms is particularly preferable.
Further, -CO-O- (CH ₂ ) _n The n of-is particularly preferably 1 to 18, preferably 6 to 14.
X in the formula ¹ Is a halogen atom such as chlorine, bromine and iodine, and a bromine atom is particularly preferred in terms of reactivity.
[0023]
The halide of the second raw material represented by the general formula (51) can be produced by a known method, and an example thereof is represented by the following reaction formula (2).
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(Where R ⁴ , Z and X ¹ Is as defined above. ), The alcohols (compound (53)) and the phosphorus halide (compound (54)) are equimolarly reacted at 20 ° C in a solvent such as benzene in the presence of a base such as pyridine. By reacting for about 18 hours, the desired halide (compound (51)) can be easily produced. In addition, such a reaction is preferably performed in the presence of a polymerization inhibitor such as phenothiazine.
[0024]
In the reaction of the first step, 4-hydroxybenzaldehyde represented by the general formula (50) is reacted with a halide represented by the general formula (51) in a solvent in the presence of a base.
[0025]
The amount of the halide represented by the general formula (51) is 1 mole or more, preferably 1.5 to 2.0 times the molar amount of the 4-hydroxybenzaldehyde represented by the general formula (50). It is.
[0026]
As the base that can be used, inorganic bases such as sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, calcium hydroxide, calcium carbonate, barium hydroxide, and calcium hydroxide; Trimethylamine, N, N-dimethylcyclohexylamine, N, N-diethylcyclohexylamine, N, N-dimethylbenzylamine, N, N′-dimethylpiperazine, N, N-dimethylaniline, N, N-diethylaniline, N, N ′, N′-tetramethyl-1,3-propanediamine, pyridine, α-picoline, β-picoline, γ-picoline, 4-ethylmorpholine, triethylenediamine, 1,3-diazabicyclo [5,4, 0] undecene, 1,8-diazabicyclo [5,4,0] -7-u Decene, N-ethylpiperidine, quinoline, isoquinoline, N, N-dimethylpiperazine, N, N-diethylpiperazine, quinaldine, 2-ethylpyridine, 4-ethylpyridine, 3,5-lutidine, 2,6-lutidine, -Methylmorpholine, organic bases such as 2,4,6-collidine, ion exchange resins having a pyridyl group or a dimethylaminobenzyl group, alkoxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide and the like. These are used alone or in combination of two or more, but are not particularly limited thereto.
The amount of the base to be added is usually sufficient to be equimolar to 4-hydroxybenzaldehyde represented by the general formula (50).
[0027]
Examples of the reaction solvent include one or more of ethers such as dioxane, tetrahydrofuran and dibutyl ether; nitriles such as acetonitrile and propionitrile; alcohols such as methanol and ethanol; dimethylformamide, acetone and water. Can be used.
[0028]
The reaction is performed at a reaction temperature of 0 to 100 ° C, preferably 20 to 50 ° C, and a reaction time of 0.5 to 50 hours, preferably 10 to 30 hours.
[0029]
After completion of the reaction, various operations such as washing, extraction, washing, dehydration, recrystallization, and column chromatography with an acid are performed to obtain a benzaldehyde derivative represented by the general formula (52).
[0030]
<Second step>
The second step is represented by the following reaction formula (3)
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(Where R ⁴ And Z are as defined above. X ² Represents a halogen atom. )) To obtain the benzene derivative represented by the general formula (14).
[0031]
X in the formula of p-xylenebis- (triphenylphosphonium halogen) represented by the general formula (55) ² Represents a halogen atom such as chlorine, bromine or iodine, and among them, bromine is particularly preferred in terms of reactivity. These p-xylene bis- (triphenylphosphonium halogen) can use a commercial item.
[0032]
In the reaction of the second step, the benzoaldehyde derivative represented by the general formula (52) and p-xylenebis- (triphenylphosphonium halogen) represented by the general formula (55) are dissolved in a solvent in the presence of a base. Reaction in
[0033]
The addition amount of the benzaldehyde derivative represented by the general formula (52) is 2 to 4 times, preferably 2 to 4 times the molar amount of p-xylenebis- (triphenylphosphonium halogen) represented by the general formula (55). 2.5 times mol.
[0034]
The base that can be used in the second step is not particularly limited, for example, metal hydrides such as sodium hydride, amines such as trimethylamine and triethylamine, potassium hydroxide, alkali hydroxides such as sodium hydroxide, Alkoxides such as sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide and the like, piperidine, pyridine, potassium cresolate, alkyllithium and the like are used, and these are used alone or in combination of two or more.
The amount of these bases to be added is 1 to 5 moles, preferably 3.5 to 4.5 moles relative to p-xylenebis- (triphenylphosphonium halogen) represented by the general formula (55). is there.
[0035]
As the reaction solvent, for example, one or more of ethers such as dioxane, tetrahydrofuran and dibutyl ether, nitriles such as acetonitrile and propionitrile, alcohols such as methanol and ethanol, dimethylformamide, and acetone are used. be able to.
[0036]
The reaction is performed at a reaction temperature of 0 to 100 ° C, preferably 20 to 50 ° C, and a reaction time of 0.5 to 50 hours, preferably 5 to 30 hours.
[0037]
After completion of the reaction, the resultant is filtered, optionally washed, and dried to obtain the benzene derivative represented by the general formula (14).
[0038]
The benzene derivative liquid crystalline compound represented by the general formula (14) thus obtained is a novel compound, and in the present invention, the benzene derivative liquid crystalline compound represented by the general formula (14) obtained as desired is obtained according to the present invention. And heat treatment in a solvent in the presence of iodine.
By this heat treatment, the benzene derivative liquid crystal compound represented by the general formula (14) can be selectively converted to a trans form.
In this case, the addition amount of iodine is 0.001 to 0.1 times mol, preferably 0.005 to 0.01 times mol, of the benzene derivative liquid crystal compound represented by the general formula (14). The processing temperature is 100 to 180 ° C, preferably 130 to 150 ° C. Examples of the solvent that can be used include, for example, benzene, toluene, o-xylene, m-xylene, p-xylene, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and the like. One or more solvents can be used.
[0039]
The benzene derivative represented by the general formula (14) is a compound having a liquid crystallinity, emitting blue light, and having a charge transporting ability. For example, an optical sensor utilizing charge transporting properties, organic electroluminescence To be used as materials for devices (EL devices), photoconductors, spatial modulation devices, thin film transistors, charge transport materials for electrophotographic photoreceptors, photolithography, solar cells, nonlinear optical materials, organic semiconductor capacitors, and other sensors Can be.
[0040]
At least one selected from liquid crystal compounds having a long linear conjugated structure represented by the general formulas (1) to (7) of the present invention or liquid crystal compounds having a long linear conjugated structure derived therefrom. A liquid crystalline material containing one kind can be suitably used as a charge transport material.
[0041]
Here, a liquid crystal compound having a long linear conjugated structure derived from the liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) is unsaturated at the terminal. A compound having a bond refers to a homopolymer, a copolymer, a high-molecular-weight compound cross-linked by a cross-linking agent, or a high-molecular-weight compound obtained by an addition reaction with a high-molecular compound having a hydrosilyl group (hereinafter, referred to as a high-molecular compound). , "Polymer").
[0042]
The polymer may have a repeating unit derived from acrylic acid, methacrylic acid, styrene, or the like as a copolymer component. In addition, R in the formula of the liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7). ² May be a copolymer of a mixture of different ones. In the case of a copolymer, the reaction residue of the liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) accounts for 50 mol% or more, preferably 70 mol% or more, of the copolymer. Mol% or more, more preferably 80 mol% or more.
The molecular weight of the polymer is such that the number average molecular weight is in the range of 1,000 to tens of millions, preferably in the range of tens of thousands to millions.
The polymer can be produced by the following method. For example, a homopolymer, a copolymer of a liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7), or a high molecular weight compound crosslinked by a crosslinking agent is produced. To perform a polymerization reaction of a desired monomer or a desired monomer and a crosslinking agent in the presence of a polymerization initiator by a radical polymerization method such as a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method. It can be manufactured by the following.
[0043]
Further, in order to produce a high molecular weight compound by subjecting a polymer compound having a hydrosilyl group to an addition reaction with a liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7). A polymer compound having a hydrosilyl group and a liquid crystal compound having a long linear conjugated structure represented by the above general formulas (1) to (7) are combined with chloroplatinic acid, an alcohol solution of chloroplatinic acid, and platinum. It can be produced by performing a reaction in the presence of a rhodium-based catalyst such as a complex of an olefin complex or a complex of rhodium and carbonyl.
[0044]
In the charge transport method of the present invention, the liquid crystalline compounds having a long linear conjugated structure represented by the general formulas (1) to (7) can be used alone or as a mixture of two or more of them. Needless to say, a composition containing the liquid crystal compound, the polymer, or a liquid crystal material composed of the composition containing the polymer can be suitably used as the charge transport material.
[0045]
The composition containing a liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) is a long linear conjugated structure represented by the general formulas (1) to (7). It contains at least 30% by weight or more, preferably 50% by weight or more, and more preferably 90% by weight or more of a liquid crystal compound having a conjugated structure portion, and is a long linear compound represented by the general formulas (1) to (7). It shows a liquid crystal state of a smectic phase caused by a liquid crystal compound having a conjugated structure portion.
As other components in such a composition, for example, one or more other liquid crystal compounds or other compounds having a long linear conjugate system, both ends of which are alkyl groups or alkoxy groups, may be used. The compound having a long linear conjugate system of other components and having an alkyl group or an alkoxy group at both ends may or may not be a liquid crystal compound. Further, other compounds having both long linear conjugated systems and having an alkyl group or an alkoxy group at both ends are liquid crystal compounds having a long linear conjugated structure represented by the general formulas (1) to (7). There may be.
The composition containing a liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) can be prepared as follows. That is, after dissolving a liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) and the above-described desired components in a solvent, the solvent is removed by heating, reducing pressure, or the like. Mixing a liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) with a desired component and melting by heating, or performing sputtering, vacuum deposition, or the like. Can be prepared.
[0046]
Further, the composition containing the polymer contains the polymer at least 30% by weight or more, preferably 50% by weight or more, more preferably 80% by weight or more, and the general formulas (1) to (7). This shows a liquid crystal state of a smectic phase caused by a liquid crystal compound having a long linear conjugated structure represented by the following formula.
As other components in such a composition, for example, one or more other liquid crystal compounds or other compounds having a long linear conjugate system, both ends of which are alkyl groups or alkoxy groups, may be used. The compound having a long linear conjugate system of other components and having an alkyl group or an alkoxy group at both ends may or may not be a liquid crystal compound. Further, other compounds having both long linear conjugated systems and having an alkyl group or an alkoxy group at both ends are liquid crystal compounds having a long linear conjugated structure represented by the general formulas (1) to (7). There may be.
This polymer composition can be prepared as follows. That is, after dissolving the polymer and the desired component in a solvent, the solvent is removed by heating, reducing pressure, or the like, or the polymer and the desired component are mixed and heated and melted, or sputtering or vacuum deposition. Can be prepared.
[0047]
The charge transport method of the first invention according to the present invention is characterized in that at least one of the liquid crystal compounds having a long linear conjugated structure or the liquid crystal compound having a long linear conjugated structure derived therefrom is used. A liquid crystal material having a smectic phase as a liquid crystal phase containing a seed is converted into a smectic phase at a predetermined temperature, and a voltage is applied in the liquid crystal state of the smectic phase to transport charges.
In this case, the smectic phase may be in any of A, B, C, D, E, F, G and H phases.
[0048]
According to a second aspect of the present invention, there is provided a charge transport method comprising a liquid crystal compound having a long linear conjugated structure represented by the general formulas (1) to (7) or a long linear conjugated system derived therefrom. A liquid crystal material having at least one selected from liquid crystal compounds having a structural portion is a liquid crystal material having a smectic phase, a solid state generated by a phase transition from the smectic phase, specifically, a crystal phase, a glass state, an amorphous solid , And a high charge transporting ability is exhibited only by applying a voltage without photoexcitation.
[0049]
The liquid crystalline material that can be used in the charge transport method of the second invention has a long linear conjugated structure represented by the general formulas (1) to (7) as in the charge transport method of the first invention. Examples thereof include a liquid crystal compound having a portion alone or a mixture of two or more of them, a composition containing the liquid crystal compound, the polymer, or a composition containing the polymer.
[0050]
When used in the solid state, the liquid crystal compounds having a long linear conjugated structure represented by the general formulas (1) to (7) may be used alone or as a mixture using two or more of them. The composition containing the liquid crystal compound, the polymer, or the liquid crystal material containing the composition containing the polymer is once heated to a smectic phase, and the temperature is decreased from this state to form a smectic phase. A solid state in which molecular orientation is maintained can be obtained.
[0051]
In addition, when the temperature is gradually decreased, the molecular orientation of the smectic phase can be maintained, so that a charge transporting ability superior to that obtained by rapid cooling can be exhibited.
[0052]
Next, the charge transport device according to the third and fourth aspects of the present invention will be described.
The charge transport device of the present invention comprises a single or two kinds of liquid crystal compounds having a long linear conjugated structure represented by the general formulas (1) to (7) between substrates provided with a pair of electrodes. A liquid crystal material having a smectic phase as a mixture used above, a composition containing the liquid crystal compound described above, the polymer, or a liquid crystal phase containing the composition containing the polymer (hereinafter, referred to as a “liquid crystal material”). A means for transporting charge through the liquid crystal layer by applying a voltage to the liquid crystalline material in a liquid crystal state of a smectic phase (hereinafter referred to as “1 charge transport”). Or a liquid crystal layer using the liquid crystalline material between a substrate provided with a pair of electrodes, and applying a voltage in a solid state generated by a phase transition from a smectic phase to the charge transporting material. Apply and transport charge through the liquid crystal layer Stage (hereinafter, the second charge transport element) and called. ).
[0053]
FIG. 1 is a schematic view showing one embodiment of the first charge transport device. In FIG. 1, the charge transport device of the present invention is provided with electrodes 2a and 2b made of transparent electrodes such as ITO on the surfaces of two glass substrates 1a and 1b, respectively. A cell is formed by bonding the adhesive with an adhesive while keeping the cell interval constant through the circuit 4. The liquid crystal material is injected into the cell, the liquid crystal layer 3 is provided between the electrodes, and the electrodes 2a and 2b are When a voltage is applied in the liquid crystal state of the liquid crystal material in the smectic phase, a high current density can be obtained through the liquid crystal layer, and charge can be transported.
[0054]
FIG. 2 is a schematic view showing one embodiment of the above-mentioned charge transport device. In FIG. 2, the charge transport device of the present invention is provided with electrodes 2a and 2b made of transparent electrodes such as ITO on the surfaces of two glass substrates 1a and 1b, respectively. A cell is prepared by bonding with an adhesive while keeping the cell interval constant through the above, and the liquid crystal material is injected into the cell to provide a liquid crystal layer 13 between the electrodes. It is formed by connecting voltage applying means 5 for applying a voltage in a solid state generated by a phase transition of a smectic phase of a liquid crystalline material. When a voltage is applied to the charge transporting material of the liquid crystal layer 13 in a solid state caused by a phase transition from the smectic phase to the charge transporting material including the voltage applying means 5 and a temperature adjusting means (not shown) for the liquid crystal phase, the liquid crystal layer is restored Thus, a high current density can be obtained, and charge can be transported.
[0055]
The liquid crystalline compound having a long linear conjugated structure represented by the general formulas (1) to (7) used as the charge transporting material of the present invention has a liquid crystal state of a smectic phase or a phase having a temperature lowering from the smectic phase. By utilizing the molecular orientation having a layered arrangement of the solid state smectic phase generated by the transition, the overlap of the long conjugated π-electron system of the liquid crystal compound becomes dense and becomes 500 μA / cm. ² Order or more, preferably 1 milliA / cm ² It can transport charges at a current density higher than that of the order, and by utilizing this charge transport property, an optical sensor, an organic electroluminescence element (EL element), a photoconductor, a spatial modulation element, a thin film transistor, and an electrophotographic photosensitive member It can be suitably used as a charge transport method for materials such as charge transport materials, photolithography, solar cells, nonlinear optical materials, organic semiconductor capacitors, and other sensors.
[0056]
For example, when the liquid crystalline material of the present invention is used for an organic electroluminescent element (EL element), two electrodes (at least one of which is made of ITO) are formed by adding a light-emitting material to another light-emitting layer as necessary. Transparent electrode). In the case of a multilayer organic light emitting device, the charge transport material of the present invention can be used as a hole transport layer, an electron transport layer, or a light emitting layer. In the case of an optical sensor, a current change due to light irradiation can be detected by sandwiching the liquid crystalline material of the present invention between two electrodes (at least one of which is transparent). When used as an electrophotographic photoreceptor or an image storage element, it can be prepared by laminating a charge generation layer and the charge transport layer of the present invention on a substrate or an electrode.
[0057]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.
Example 1
<First step>
The following reaction formula (4)
Embedded image

In accordance with the above, p- (9-decenoxy) -benzaldehyde (compound (57)) was synthesized.
50 ml of an ethanol solution in which 1.12 g (0.02 mol) of potassium hydroxide was dissolved was added to a solution in which 2.44 g (0.02 mol) of 4-hydroxybenzaldehyde (compound (50)) was dissolved in 30 ml of ethanol. This is stirred and ethanol is removed under reduced pressure by an evaporator. The residue is dissolved in 50 ml of DMF, and 10 ml of a DMF solution in which 6.57 g (0.03 mol) of 10-bromo-1-decene (compound (56)) is dissolved is added dropwise. The reaction was performed at 70 ° C. for 15 hours under a nitrogen atmosphere. After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was poured into ice-dilute hydrochloric acid. Next, diethyl ether was added thereto, and the mixture was extracted. After dehydration with anhydrous sodium sulfate overnight, the anhydrous sodium sulfate was removed by filtration, and the diethyl ether was removed by an evaporator. The removed diethyl ether was separated into the solvent by column chromatography, dried, and dried, and 3.62 g (yield 69.5%) of p- (9-decenoxy) -benzaldehyde (compound (57)) as a pale yellow liquid was obtained. ) Got.
<Identification data>
・ ¹ H-NMR (δ, CDCl ₃ ):
0.8 to 2.0 (m, 14H,-(CH ₂ ) ₇ −), 4.0 (t, 2H, —O—CH ₂ -), 4.9 to 5.1 (d, 2H, -C = CH ₂ ), 5.3-6.2 (m, 1H, -CH = C), 7.0, 7, 9 (d, 4H, aromatic), 10 (s, 1H, -CHO)
[0058]
<Second step>
The second step is represented by the following reaction formula (5)
Embedded image

In accordance with the above, a benzene derivative (compound (59)) was synthesized.
2.60 g (0.01 mol) of p- (9-decenoxy) -benzaldehyde (compound (57)) obtained in the first step and p-xylenebis- (triphenylphosphonium bromide) (compound (58), Tokyo, Japan) 50 ml of 0.4 mol sodium ethoxide was added dropwise to 50 ml of an ethanol solution in which 3.93 g (0.005 mol) of a chemical compound was dissolved, and the mixture was stirred at room temperature for 30 minutes and reacted at 50 ° C. for 10 hours. The reaction solution is filtered, and the precipitate is washed with a 60% aqueous ethanol solution and hexane. This was dried to obtain 1.10 g (yield 18.6%) of a benzene derivative (compound (59)) as a light yellow solid.
<Identification data>
¹ H-NMR (δ, CDCl ₃ ):
1.2 to 1.5 (m, 16H), 1.6 to 1.7 (m, 4H), 1.7 to 1.8 (m, 4H), 2.0 to 2.1 (m, 4H) ), 3.9-4.0 (t, 4H), 4.9-5.1 (d, 4H), 5.7-5.9 (m, 2H), 6.8 (d, 4H), 6.9 to 7.1 (m, 4H), 7.2 to 7.5 (m, 8H)
IR (cm ^-1 , KBr)
721 (p-ph out-of-plane bending angle), 968 (tC = C-out-of-plane bending angle), 1110 to 1253 (CO-C expansion and contraction), 1465 to 1573 (ph skeleton vibration), 1641 (CH ₂ = CH-stretch), 2852-2921 (aliphatic CH stretch)
3021-3075 (Aromatic CH stretching)
・ MASS (FAB; Xe): 590 (M-1)
[0059]
Further, from the observation of the texture of the liquid crystal phase by an X-ray diffraction analysis and a polarizing microscope, the following phase transition was revealed. In addition, FIG. 3 shows an X-ray diffraction diagram when the compound was subjected to X-ray diffraction analysis at 170 ° C.
[0060]
(Equation 1)

Cyst; crystal, SmG; smectic G phase, SmB; smectic B phase, SmA; smectic A phase, Iso; isotropic liquid
[0061]
FIG. 4 shows a fluorescence spectrum when the obtained compound was measured at an excitation wavelength of 368 nm.
[0062]
<Evaluation of charge transport ability>
A gap (about 15 μm) was provided by spacer particles on two glass substrates provided with ITO electrodes by vacuum film formation so that the ITO electrodes face each other, and the two substrates were bonded to each other to form a cell.
20 mg of the benzene derivative (compound (59)) obtained in Example 1 was injected into the cell at 230 ° C.
Next, a voltage of 5 V was applied, the temperature was gradually increased, and the amount of current at each temperature was measured. The result is shown in FIG.
The temperature was kept at 130 ° C., and the amount of current for each voltage was measured twice. The first result is shown in FIG. 6, and the second result is shown in FIG.
Further, the temperature was lowered from 130 ° C. to 100 ° C. by natural cooling, and the amount of current for each voltage was measured at 100 ° C. The result is shown in FIG.
After the temperature was lowered from 130 ° C. to 100 ° C. in a refrigerator for 10 minutes and cooled (quenched), the amount of current at each voltage was measured at 100 ° C., and the results are shown in FIG.
Further, the temperature was lowered from 130 ° C. to 50 ° C. by natural cooling, and the amount of current at each voltage was measured at 50 ° C. The result is shown in FIG.
Further, the temperature was lowered from 130 ° C. to 50 ° C. in a refrigerator in 10 minutes and cooled (rapidly cooled), and then the amount of current for each voltage was measured at 50 ° C., and the results are shown in FIG.
[0063]
【The invention's effect】
As described above, the charge transport method of the present invention is selected from a liquid crystal compound having a long linear conjugated structure having a specific structural formula or a liquid crystal compound having a long linear conjugated structure derived therefrom. A liquid crystal material having a smectic phase as a liquid crystal phase containing at least one type exhibits excellent charge transport ability by applying a voltage in a liquid crystal state of the smectic phase or a solid state generated by a phase transition from the liquid crystal state of the smectic phase. And 500 μA / cm, which is not available in conventional charge transport materials. ² Order or more, preferably 1 milliA / cm ² With the above current density, charge transport is enabled. It has a conductivity of at least 1.6 × 10 ^-7 s / cm or more, which is the value of the semiconductor region.
Therefore, the charge transport method and the charge transport element of the present invention can be used for an optical sensor utilizing charge transport properties, an organic electroluminescence element (EL element), a photoconductor, a spatial modulation element, a thin film transistor, and an electrophotographic photosensitive member. It can be suitably used as a charge transport method for charge transport materials, photolithography, solar cells, nonlinear optical materials, organic semiconductor capacitors, organic semiconductor capacitors, and other sensors.
[0064]
[Brief description of the drawings]
FIG. 1 is a schematic view showing one embodiment of a charge transport device of the present invention.
FIG. 2 is a schematic view showing one embodiment of the charge transport device of the present invention.
FIG. 3 is an X-ray diffraction diagram when the benzene derivative obtained in Example 1 is measured at 170 ° C.
FIG. 4 is a diagram showing a fluorescence spectrum when the benzene derivative obtained in Example 1 is measured at an excitation wavelength of 368 nm.
FIG. 5 is a diagram showing the relationship between temperature and current when a voltage of 5 V is applied to the benzene derivative obtained in Example 1, the temperature is gradually increased, and the current at each temperature is measured.
FIG. 6 is a diagram showing the relationship between voltage and current amount when the benzene derivative obtained in Example 1 is maintained at a temperature of 130 ° C. (first time).
FIG. 7 is a diagram showing the relationship between voltage and current amount while the benzene derivative obtained in Example 1 is kept at a temperature of 130 ° C. (second time).
FIG. 8 is a graph showing the relationship between the voltage and current at 100 ° C. and the temperature obtained by heating the benzene derivative obtained in Example 1 to 130 ° C. and lowering the temperature to 100 ° C. by natural cooling. FIG. 4 is a diagram showing the relationship between voltage and current at 100 ° C. by heating the benzene derivative to 130 ° C. and rapidly cooling to 100 ° C .;
FIG. 9 is a graph showing the relationship between voltage and current at 50 ° C. and the temperature obtained by heating the benzene derivative obtained in Example 1 to 130 ° C. and lowering the temperature to 50 ° C. by natural cooling. FIG. 4 is a diagram showing the relationship between voltage and current at 50 ° C. by heating the benzene derivative to 130 ° C. and rapidly cooling it to 50 ° C .;
[0065]
[Explanation of symbols]
1a, 1b Glass substrate
2a, 2b electrode
4 Spencer
3,13 liquid crystal layer
5 Voltage application means

Claims (5)

The following general formula (1)

The following general formula (2)

The following general formula (3)

The following general formula (4)

The following general formula (5)

The following general formula (6)

The following general formula (7)

(R ¹ or R ² in the general formulas (1) to (7) represents a linear or branched alkyl group, an alkoxy group, or the following general formula (8)

In the formula, R ³ is a hydrogen atom or a methyl group, B is — (CH ₂ ) _m —, — (CH ₂ ) _m —O—, —CO—O— (CH ₂ ) _m —, —CO—O— _{(CH 2) m -O -,} - C 6 H 4 -CH 2 -O -, - shows a CO-. Represents｝.
A represents the following general formulas (9) to (13)

Is shown. R ¹ and R ² may be the same or different groups. )) Or a liquid crystal compound having at least one selected from liquid crystal compounds having a long linear conjugated structure derived therefrom. A charge transport method, wherein a voltage is applied to the liquid crystal material in a smectic phase liquid crystal state. The liquid crystalline compound having the long linear conjugated structure has the following general formula (14)

(Wherein, R ⁴ represents a hydrogen atom or a methyl group, Z represents an alkylene group, —CO—O— (CH ₂ ) _n , —C ₆ H ₄ —CH ₂ —, or —CO—). The charge transport method according to claim 1, wherein the charge transport method is a benzene derivative liquid crystalline compound. At least one selected from liquid crystal compounds having a long linear conjugated structure represented by the general formulas (1) to (7) or liquid crystal compounds having a long linear conjugated structure derived therefrom A charge transport method comprising applying a voltage in a solid state generated by a phase transition from a smectic phase to a liquid crystalline material having a smectic phase as a liquid crystal phase containing. A liquid crystal compound having a long linear conjugated structure represented by the above general formulas (1) to (7) or a liquid crystal having a long linear conjugated structure derived therefrom between substrates provided with a pair of electrodes A liquid crystal material having a smectic phase as a liquid crystal phase containing at least one selected from the non-volatile compounds, and having means for applying a voltage in a liquid crystal state of the smectic phase and transporting charges through the liquid crystal layer. Charge transport device. A liquid crystal compound having a long linear conjugated structure represented by the above general formulas (1) to (7) or a liquid crystal having a long linear conjugated structure derived therefrom between substrates provided with a pair of electrodes A liquid crystal material having a smectic phase as a liquid crystal phase containing at least one selected from the non-volatile compounds, and a means for applying a voltage in a solid state generated by a phase transition from the smectic phase to transport charges. Charge transport device.

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