JPH06140156A - Electroluminescent element - Google Patents
Electroluminescent elementInfo
- Publication number
- JPH06140156A JPH06140156A JP4291358A JP29135892A JPH06140156A JP H06140156 A JPH06140156 A JP H06140156A JP 4291358 A JP4291358 A JP 4291358A JP 29135892 A JP29135892 A JP 29135892A JP H06140156 A JPH06140156 A JP H06140156A
- Authority
- JP
- Japan
- Prior art keywords
- organic
- oxadiazole
- polycyclic aromatic
- condensed polycyclic
- injection electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000002347 injection Methods 0.000 claims abstract description 30
- 239000007924 injection Substances 0.000 claims abstract description 30
- WCPAKWJPBJAGKN-UHFFFAOYSA-N oxadiazole Chemical group C1=CON=N1 WCPAKWJPBJAGKN-UHFFFAOYSA-N 0.000 claims abstract description 29
- -1 oxadiazole compound Chemical class 0.000 claims abstract description 24
- 150000001875 compounds Chemical class 0.000 claims description 20
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 10
- 230000005525 hole transport Effects 0.000 claims description 9
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 claims description 6
- BBEAQIROQSPTKN-UHFFFAOYSA-N pyrene Chemical compound C1=CC=C2C=CC3=CC=CC4=CC=C1C2=C43 BBEAQIROQSPTKN-UHFFFAOYSA-N 0.000 claims description 6
- YNPNZTXNASCQKK-UHFFFAOYSA-N Phenanthrene Natural products C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 125000003118 aryl group Chemical group 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 125000003367 polycyclic group Chemical group 0.000 claims description 4
- GVEPBJHOBDJJJI-UHFFFAOYSA-N fluoranthrene Natural products C1=CC(C2=CC=CC=C22)=C3C2=CC=CC3=C1 GVEPBJHOBDJJJI-UHFFFAOYSA-N 0.000 claims description 3
- 125000001792 phenanthrenyl group Chemical group C1(=CC=CC=2C3=CC=CC=C3C=CC12)* 0.000 claims 1
- 239000010410 layer Substances 0.000 description 53
- 239000000126 substance Substances 0.000 description 26
- 239000000463 material Substances 0.000 description 10
- 238000000034 method Methods 0.000 description 8
- 239000000758 substrate Substances 0.000 description 5
- 239000013078 crystal Substances 0.000 description 4
- 150000004985 diamines Chemical class 0.000 description 4
- 238000005401 electroluminescence Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 239000011368 organic material Substances 0.000 description 3
- 150000004866 oxadiazoles Chemical class 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 125000004494 ethyl ester group Chemical group 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical group [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 2
- 125000002080 perylenyl group Chemical group C1(=CC=C2C=CC=C3C4=CC=CC5=CC=CC(C1=C23)=C45)* 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910017911 MgIn Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000012044 organic layer Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229920003227 poly(N-vinyl carbazole) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電界発光素子に関し、
特に、有機電子輸送層に新規な有機材料を用いた有機電
界発光素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device,
In particular, it relates to an organic electroluminescent device using a novel organic material for the organic electron transport layer.
【０００２】[0002]
【従来の技術】近年、情報機器の多様化に伴って、ＣＲ
Ｔより低消費電力で空間占有容積が少ない平面表示素子
のニーズが高まっている。このような平面表示素子とし
ては、液晶、プラズマディスプレイ等があるが、特に最
近は、自己発光型で表示が鮮明な電界発光素子が注目さ
れている。2. Description of the Related Art In recent years, with the diversification of information equipment, CR
There is an increasing need for a flat panel display device that consumes less power and occupies less space than T. Liquid crystal displays, plasma displays, and the like are available as such flat display elements, and in recent years, self-emission type electroluminescent elements with clear display have been receiving attention.
【０００３】ここで、電界発光素子は構成する材料によ
り、無機電界発光素子と有機電界発光素子とに大別する
ことができ、無機電界発光素子は既に実用化されてい
る。しかしながら、無機電界発光素子の駆動方式は、高
電界の印加によって加速された電子が、発光中心を衝突
励起して発光させるという所謂衝突励起型発光であるた
め、高電圧で駆動する必要がある。このため、周辺機器
の高コスト化を招来するという課題を有していた。Here, the electroluminescent element can be roughly classified into an inorganic electroluminescent element and an organic electroluminescent element depending on the constituent materials, and the inorganic electroluminescent element has already been put into practical use. However, the driving method of the inorganic electroluminescence device is so-called collision excitation type light emission in which electrons accelerated by application of a high electric field collide with each other to excite the emission center to emit light, so that it is necessary to drive at a high voltage. Therefore, there is a problem that the cost of the peripheral device is increased.
【０００４】これに対し、有機電界発光素子は、電極か
ら注入された電荷が発光体中で再結合して発光するとい
う、所謂、注入型発光であるため、低電圧で駆動するこ
とができる。しかも、有機化合物の分子構造を変更する
ことによって任意の発光色を容易に得ることができると
いった利点もある。したがって、有機電界発光素子は、
これからの表示素子として、非常に有望である。On the other hand, the organic electroluminescence device is a so-called injection type light emission in which the charges injected from the electrodes are recombined in the light emitting body to emit light, and thus can be driven at a low voltage. Moreover, there is an advantage that an arbitrary luminescent color can be easily obtained by changing the molecular structure of the organic compound. Therefore, the organic electroluminescent device is
It is very promising as a display device in the future.
【０００５】ここで、有機電界発光素子は、一般に、２
層構造〔ホール注入電極と電子注入電極との間に、ホー
ル輸送層と、発光層とが形成された構造（ＳＨ−Ａ構
造）、またはホール注入電極と電子注入電極との間に、
発光層と、電子輸送層とが形成された構造（ＳＨ−Ｂ構
造）〕或いは３層構造〔ホール注入電極と電子注入電極
との間に、ホール輸送層と、発光層と、電子輸送層とが
形成された構造（ＤＨ構造）〕のような素子構造を有し
ている。上記ホール注入電極としては、金やＩＴＯのよ
うな仕事関数の大きな電極材料を用い、上記電子注入電
極としては、Ｍｇのような仕事関数の小さな電極材料を
用いる。また、上記ホール輸送層、発光層、電子輸送層
には有機材料が用いられ、ホール輸送層はｐ型半導体の
性質、電子輸送層はｎ型半導体の性質を有する材料が用
いられる。上記発光層は、上記ＳＨ−Ａ構造ではｎ型半
導体の性質、ＳＨ−Ｂ構造ではｐ型半導体の性質、ＤＨ
構造では中性に近い性質を有する材料が用いられる。い
ずれにしてもホール注入電極から注入されたホールと電
子注入電極から注入された電子が発光層とホール（又
は、電子）輸送層の界面、及び発光層内で再結合して発
光するという原理である。Here, the organic electroluminescent device is generally composed of 2
Layer structure [A structure in which a hole transport layer and a light emitting layer are formed between a hole injection electrode and an electron injection electrode (SH-A structure), or between a hole injection electrode and an electron injection electrode,
Structure in which light emitting layer and electron transport layer are formed (SH-B structure)] or three-layer structure [hole transport layer, light emitting layer, and electron transport layer between hole injection electrode and electron injection electrode] Element structure (DH structure)]. An electrode material having a large work function such as gold or ITO is used as the hole injecting electrode, and an electrode material having a small work function such as Mg is used as the electron injecting electrode. An organic material is used for the hole transport layer, the light emitting layer, and the electron transport layer, and a material having a p-type semiconductor property for the hole transport layer and an n-type semiconductor property for the electron transport layer is used. The light emitting layer has an n-type semiconductor property in the SH-A structure, a p-type semiconductor property in the SH-B structure, and DH.
A material having a property close to neutrality is used for the structure. In any case, the principle is that the holes injected from the hole injection electrode and the electrons injected from the electron injection electrode recombine at the interface between the light emitting layer and the hole (or electron) transport layer and in the light emitting layer to emit light. is there.
【０００６】[0006]
【発明が解決しようとする課題】ところで、上記有機電
界発光素子の有機材料の選択は、素子の諸特性に大きく
影響を与える。この諸特性の中でも、素子の耐久性の向
上は重要な課題である。この耐久性を向上させる一つの
方法として、有機電子輸送層に製膜性がよく、結晶化し
にくい材料を用いる方法がある。By the way, the selection of the organic material of the organic electroluminescence device has a great influence on various characteristics of the device. Among these characteristics, improving the durability of the device is an important issue. As one method of improving the durability, there is a method of using a material having good film-forming property and hardly crystallizing for the organic electron transport layer.
【０００７】現在、知られている比較的製膜性が良く、
結晶化の起こりにくい化合物としては、特願平３−２２
２７９３号に記載のオキサジアゾール系化合物がある。
しかしながら、この化合物を有機電子輸送層の材料とし
て用いた電界発光素子も耐久性の良さは充分ではなく、
更なる耐久性の向上が必要となっている。本発明は、上
記現状に鑑みなされたものであり、耐久性の高い電界発
光素子を提供することを目的とする。At present, the known film-forming property is relatively good,
As a compound which hardly crystallizes, Japanese Patent Application No. 3-22
There are oxadiazole compounds described in 2793.
However, the electroluminescence device using this compound as the material of the organic electron transport layer also has insufficient durability,
Further improvement in durability is required. The present invention has been made in view of the above circumstances, and an object thereof is to provide an electroluminescent element having high durability.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成するため
に、請求項１の発明は、ホール注入電極と、電子注入電
極との間に、有機ホール輸送層と、有機発光層と、有機
電子輸送層とがホール注入電極側から順に形成された有
機３層構造、或いはホール注入電極と、電子注入電極と
の間に、有機発光層と有機電子輸送層とがホール注入電
極側から順に形成された有機２層構造を有する電界発光
素子において、前記有機電子輸送層には、複数のオキサ
ジアゾール環を有しており、しかも各々のオキサジアゾ
ール環が縮合多環芳香族によって置換されているオキサ
ジアゾール系化合物が用いられていることを特徴とす
る。In order to achieve the above object, the invention of claim 1 provides an organic hole transport layer, an organic light emitting layer, and an organic electron between a hole injection electrode and an electron injection electrode. An organic three-layer structure in which a transport layer is sequentially formed from the hole injecting electrode side, or an organic light emitting layer and an organic electron transport layer are sequentially formed between the hole injecting electrode and the electron injecting electrode. In the electroluminescent device having an organic two-layer structure, the organic electron transport layer has a plurality of oxadiazole rings, and each oxadiazole ring is substituted with a condensed polycyclic aromatic group. An oxadiazole-based compound is used.
【０００９】請求項２の発明は、請求項１記載の縮合多
環芳香族が、ベンゼン環２個からなる縮合多環芳香族で
あることを特徴とする。請求項３の発明は、請求項１記
載の縮合多環芳香族が、ベンゼン環３個からなる縮合多
環芳香族であることを特徴とする。請求項４の発明は、
請求項３記載の縮合多環芳香族が、アントラセン、フェ
ナントレンであることを特徴とする。The invention of claim 2 is characterized in that the condensed polycyclic aromatic compound according to claim 1 is a condensed polycyclic aromatic compound having two benzene rings. The invention of claim 3 is characterized in that the condensed polycyclic aromatic compound of claim 1 is a condensed polycyclic aromatic compound composed of three benzene rings. The invention of claim 4 is
The condensed polycyclic aromatic compound according to claim 3 is anthracene or phenanthrene.
【００１０】請求項５の発明は、請求項１記載の縮合多
環芳香族が、ベンゼン環が４個からなる縮合多環芳香族
であることを特徴とする。請求項６の発明は、請求項５
記載の縮合多環芳香族が、ピレンであることを特徴とす
る。請求項７の発明は、請求項１記載のオキサジアゾー
ル系化合物は、オキサジアゾール環の間にベンゼン環を
有し、且つ、そのベンゼン環が、オキサジアゾール環の
縮合多環芳香族と結合していない炭素と結合しているこ
とを特徴とする。The invention of claim 5 is characterized in that the condensed polycyclic aromatic compound according to claim 1 is a condensed polycyclic aromatic compound having four benzene rings. The invention of claim 6 relates to claim 5
The condensed polycyclic aromatic compound described is pyrene. According to the invention of claim 7, the oxadiazole-based compound according to claim 1 has a benzene ring between the oxadiazole rings, and the benzene ring is a condensed polycyclic aromatic ring of the oxadiazole ring. It is characterized in that it is bonded to carbon which is not bonded.
【００１１】請求項８の発明は、請求項１記載のオキサ
ジアゾール系化合物は、オキサジアゾール環の間にアル
キル鎖を有し、且つ、そのアルキル鎖が、オキサジアゾ
ール環の縮合多環芳香族と結合していない炭素と結合し
ていることを特徴とする。According to an eighth aspect of the present invention, the oxadiazole compound according to the first aspect has an alkyl chain between the oxadiazole rings, and the alkyl chain is a condensed polycyclic ring of the oxadiazole ring. It is characterized in that it is bonded to a carbon that is not bonded to an aromatic.
【００１２】[0012]
【作用】上記のように構成することにより、以下のよう
な作用が得られる。先ず、本発明のオキサジアゾール系
化合物は、分子内に嵩高い縮合多環芳香族基を有する。
製膜された化合物の結晶化は、分子が規則正しく並ぶこ
とによって起こるが、本発明のオキサジアゾール系化合
物の場合、この嵩高い縮合多環芳香族基が分子が規則正
しく並ぶことを邪魔することにより、製膜後も結晶化を
起こしにくく製膜性がよい。With the above-mentioned structure, the following actions can be obtained. First, the oxadiazole-based compound of the present invention has a bulky condensed polycyclic aromatic group in the molecule.
Crystallization of the film-formed compound occurs due to regular arrangement of molecules, but in the case of the oxadiazole-based compound of the present invention, this bulky fused polycyclic aromatic group prevents the regular arrangement of molecules. Also, crystallization is less likely to occur even after film formation, and film formability is good.
【００１３】加えて、本発明のオキサジアゾール系化合
物は、膜形成を行なった際に、上記特願平３−２２２７
９３号に記載のオキサジアゾール系化合物より、有機発
光層に用いた化合物となじみが良く、製膜した後の膜の
状態が良いという利点を有している。ここで、本発明の
オキサジアゾール系化合物は、一般に、下記化１或いは
化２に示すような方法で合成する。尚、反応時間につい
ては、各々の化合物により異なっている。In addition, the oxadiazole-based compound of the present invention has the above-mentioned Japanese Patent Application No. 3-2227 when a film is formed.
The oxadiazole-based compound described in No. 93 has an advantage that it is more compatible with the compound used for the organic light-emitting layer and the state of the film after film formation is good. Here, the oxadiazole-based compound of the present invention is generally synthesized by the method shown in Chemical formula 1 or Chemical formula 2 below. The reaction time differs depending on each compound.
【００１４】[0014]
【化１】 [Chemical 1]
【００１５】[0015]
【化２】 [Chemical 2]
【００１６】[0016]
【実施例】本発明の実施例を図面に基づいて以下に、説
明を行なう。 （実施例１）図１は、本発明の一実施例に係る電界発光
素子の断面図であり、ガラス基板１上には、ホール注入
電極２と、有機ホール輸送層３と、有機発光層４と、有
機電子輸送層５と、電子注入電極６とが、ガラス基板１
側から順に形成されている。Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of an electroluminescent device according to an embodiment of the present invention, in which a hole injection electrode 2, an organic hole transport layer 3, and an organic light emitting layer 4 are formed on a glass substrate 1. The organic electron transport layer 5 and the electron injection electrode 6
It is formed in order from the side.
【００１７】それぞれの部材の材料としては、ホール注
入電極２にはインジウム−スズ酸化物（ＩＴＯ）、有機
ホール輸送層３には下記化３に示すジアミン誘導体（Ｔ
ＰＤ）、有機発光層４には下記化４に示すペリレン誘導
体、有機電子輸送層５には下記化５に示すオキサジアゾ
ール系化合物、電子注入電極６にはＭｇＩｎ合金が、そ
れぞれ用いられている。The material of each member is indium-tin oxide (ITO) for the hole injecting electrode 2, and the diamine derivative (T) shown in the following chemical formula 3 for the organic hole transporting layer 3.
PD), the organic light emitting layer 4 is made of a perylene derivative shown in Chemical formula 4, the organic electron transport layer 5 is made of an oxadiazole compound shown in Chemical formula 5 below, and the electron injection electrode 6 is made of a MgIn alloy. .
【００１８】[0018]
【化３】 [Chemical 3]
【００１９】[0019]
【化４】 [Chemical 4]
【００２０】[0020]
【化５】 [Chemical 5]
【００２１】ここで、上記構成の電界発光素子を、以下
のようにして作製した。先ず、ガラス基板１上にインジ
ウム−スズ酸化物（ＩＴＯ）からなるホール注入電極２
が形成された基板を、中性洗剤、及び、水により洗浄し
た後、アセトン中で２０分間、イソプロピルアルコール
中で約２０分間超音波洗浄をした。この後、上記ホール
注入電極２上に、ジアミン誘導体（ＴＰＤ 上記化３に
示す）を真空蒸着して有機ホール輸送層３を形成した
後、この有機ホール輸送層３上に、ペリレン誘導体（上
記化４に示す）を真空蒸着して、有機発光層４を形成し
た。さらに、有機発光層４上にオキサジアゾール系化合
物（上記化５に示す）を真空蒸着して有機電子輸送層５
を作製した。しかる後、有機電子輸送層５上に、Ｍｇと
Ｉｎとを１０：１の比率で共蒸着して、電子注入電極６
を形成して、電界発光素子を作製した。尚、上記蒸着は
いずれも、真空度１×１０-6Ｔｏｒｒ、基板温度２０
℃、有機層の蒸着速度２Å／ｓｅｃという条件下で行っ
た。Here, the electroluminescent device having the above structure was manufactured as follows. First, a hole injection electrode 2 made of indium-tin oxide (ITO) is formed on a glass substrate 1.
The substrate on which was formed was washed with a neutral detergent and water, and then ultrasonically washed in acetone for 20 minutes and in isopropyl alcohol for about 20 minutes. Then, a diamine derivative (TPD shown in the above Chemical Formula 3) is vacuum-deposited on the hole injecting electrode 2 to form an organic hole transporting layer 3, and then the perylene derivative (the above chemical formula) is formed on the organic hole transporting layer 3. 4) was vacuum-deposited to form the organic light emitting layer 4. Further, an oxadiazole compound (shown in Chemical Formula 5 above) is vacuum-deposited on the organic light emitting layer 4 to form an organic electron transport layer 5.
Was produced. After that, Mg and In are co-deposited on the organic electron transport layer 5 in a ratio of 10: 1 to form an electron injection electrode 6
To form an electroluminescent device. In all of the above vapor depositions, the degree of vacuum was 1 × 10 −6 Torr and the substrate temperature was 20.
C., and the vapor deposition rate of the organic layer was 2Å / sec.
【００２２】ところで、上記オキサジアゾール系化合物
の合成は、以下のようにして行った。先ず、下記化６に
示すように、市販のカルボキシル基を有する縮合多環芳
香族化合物より、C. Gundu Rao等の方法（ORGANIC PREP
ARETIONS AND PROCEDURES INT. 12(3-4),P.225-228(19
80))に基づいてエチルエステルを合成した。By the way, the above-mentioned oxadiazole compound was synthesized as follows. First, as shown in the following chemical formula 6, from the commercially available condensed polycyclic aromatic compound having a carboxyl group, the method of C. Gundu Rao et al. (ORGANIC PREP
ARETIONS AND PROCEDURES INT. 12 (3-4), P.225-228 (19
80)) was used to synthesize the ethyl ester.
【００２３】[0023]
【化６】 [Chemical 6]
【００２４】続いて、下記化７に示すように、上記反応
によって得られたエチルエステルを用いて浜田等の方法
（日本化学会誌，1991,(11),p.1540-1548)に基づいて合
成した。Then, as shown in the following chemical formula 7, the ethyl ester obtained by the above reaction was used for the synthesis according to the method of Hamada et al. (Journal of the Chemical Society of Japan, 1991, (11), p.1540-1548). did.
【００２５】[0025]
【化７】 [Chemical 7]
【００２６】このように作製した電界発光素子を、以下
（ａ1 ）素子と称する。 （実施例２〜４）有機電子輸送層の材料として、下記化
８〜化１０に示すオキサジアゾール系化合物を用いた以
外は、上記実施例１と同様に素子を作製した。The electroluminescent device thus manufactured is hereinafter referred to as (a 1 ) device. (Examples 2 to 4) Devices were produced in the same manner as in Example 1 except that the oxadiazole compounds shown in Chemical formulas 8 to 10 below were used as the material of the organic electron transport layer.
【００２７】[0027]
【化８】 [Chemical 8]
【００２８】[0028]
【化９】 [Chemical 9]
【００２９】[0029]
【化１０】 [Chemical 10]
【００３０】また、オキサジアゾール系化合物の合成も
上記実施例１の合成方法と同様の手順で行なった。この
ように作製した電界発光素子を、それぞれ以下（ａ2 ）
素子〜（ａ4 ）素子と称する。 （比較例１、２）有機電子輸送層の材料として、下記化
１１、化１２に示す縮合多環芳香族を有していないオキ
サジアゾール系化合物を用いた以外は、上記実施例１と
同様に素子を作製した。The oxadiazole compound was also synthesized by the same procedure as in the synthesis method of Example 1. The electroluminescent elements produced in this manner are respectively described below (a 2 )
Elements to (a 4 ) elements. (Comparative Examples 1 and 2) Same as Example 1 except that the oxadiazole-based compound having no condensed polycyclic aromatic group shown in Chemical formulas 11 and 12 below was used as the material of the organic electron transport layer. An element was prepared in.
【００３１】[0031]
【化１１】 [Chemical 11]
【００３２】[0032]
【化１２】 [Chemical 12]
【００３３】このように、作製した電界発光素子を、そ
れぞれ以下（ｘ1 ）素子、（ｘ2 ）素子と称する。 〔実験１〕上記本発明の（ａ1 ）素子〜（ａ4 ）素子、
及び、比較例の（ｘ1 ）素子、（ｘ2 ）素子を用いて、
ホール注入電極２側にプラス、電子注入電極５側にマイ
ナスを直流電圧として印加し、発光時間、最高輝度等の
発光特性を調べたので、下記表１に示す。The electroluminescent elements thus manufactured are hereinafter referred to as (x 1 ) element and (x 2 ) element, respectively. [Experiment 1] (a 1 ) element to (a 4 ) element of the present invention,
And using the (x 1 ) element and the (x 2 ) element of the comparative example,
A positive voltage was applied as a DC voltage to the hole injection electrode 2 side and a negative voltage was applied to the electron injection electrode 5 side, and emission characteristics such as emission time and maximum brightness were examined.
【００３４】[0034]
【表１】 [Table 1]
【００３５】発光色は、赤色で発光ピーク波長は６３０
ｎｍであった。表１から明らかなように、本発明の（ａ
1 ）素子〜（ａ4 ）素子は、比較例の（ｘ1 ）素子、
（ｘ2 ）素子と比較して、発光時間が長かった。これ
は、有機電子輸送層に用いたオキサジアゾール系化合物
の製膜性が良く、結晶化しにくいため、化合物の結晶化
による素子の破壊を抑えることができたためと考えられ
る。The emission color is red and the emission peak wavelength is 630.
was nm. As is clear from Table 1, (a of the present invention
1 ) element to (a 4 ) element are the (x 1 ) element of the comparative example,
The emission time was longer than that of the (x 2 ) device. It is considered that this is because the oxadiazole-based compound used for the organic electron transporting layer had good film-forming properties and was difficult to crystallize, so that the device could be prevented from being broken by the crystallization of the compound.
【００３６】更に、製膜性の向上について調べるため
に、以下のような実験を行った。 〔実験２〕上記（ａ1 ）素子、（ａ4 ）素子、及び、
（ｘ1 ）素子（ｘ2 ）素子を用いて、製膜状態を調べた
ので、その結果を図２に示す。具体的な実験条件として
は、作成した素子を発光させずそのまま放置した場合
の、素子１ｍｍ2 当たりの結晶領域の経時変化を調べ
た。Further, the following experiment was conducted in order to investigate the improvement of the film-forming property. [Experiment 2] The (a 1 ) element, the (a 4 ) element, and
The (x 1 ) element (x 2 ) element was used to examine the film forming state. The results are shown in FIG. 2. As a concrete experimental condition, the time-dependent change of the crystal region per 1 mm 2 of the element was examined when the produced element was left as it was without emitting light.
【００３７】図２から明らかなように、（ｘ1 ）素子
（ｘ2 ）素子と比較して、本発明の（ａ1 ）素子、（ａ
4 ）素子は、約１／２〜１／３結晶が発生しにくく、ま
た結晶の成長も遅く製膜性が良いことがわかる。 〔その他の事項〕上記実施例では素子構造が、３層構造
についての説明を行なったが、２層構造の内でも、電子
注入電極とホール注入電極との間に有機電子輸送層と、
有機発光層とを有するＳＨ−Ｂ構造のもので同様の効果
を得ることができる。As is clear from FIG. 2, the (a 1 ) element and the (a 1 ) element of the present invention are compared with the (x 1 ) element (x 2 ) element.
4 ) It can be seen that in the device, about 1/2 to 1/3 crystal is hardly generated, the crystal growth is slow, and the film forming property is good. [Other Matters] In the above embodiments, the device structure has been described as having a three-layer structure. However, in the two-layer structure, an organic electron transport layer is provided between the electron injection electrode and the hole injection electrode,
A similar effect can be obtained with an SH-B structure having an organic light emitting layer.
【００３８】また、上記実施例では、縮合多環芳香族が
アントラセン、または、ナフタレンであるオキサジアゾ
ール系化合物についてしか述べていないが、本発明はこ
れに限らず、縮合多環芳香族としてフェナントレン、ピ
レンを用いることもできる。これに加えて、複数のオキ
サジアゾール環の間に、アルキル鎖が存在するオキサジ
アゾール系化合物も用いることができる。Further, in the above-mentioned examples, only the oxadiazole compound in which the condensed polycyclic aromatic is anthracene or naphthalene is described, but the present invention is not limited to this, and the condensed polycyclic aromatic is phenanthrene. , Pyrene can also be used. In addition to this, an oxadiazole-based compound having an alkyl chain between a plurality of oxadiazole rings can also be used.
【００３９】更に、ホール注入電極として、上記実施例
ではＩＴＯ膜を用いたが、この他に金の半透明膜等、仕
事関数が高く、透明性が高いものであれば用いることが
できる。また、有機ホール輸送材料として、上記化１に
示すジアミン誘導体（ＴＰＤ）を用いたが、他の各種ジ
アミン誘導体(Y.Takeshita et.al.,Report on Progress
in Polymer Physics in Japan,vol.30,503(1987))やポ
リビニルカルバゾール(T.Fujii et al.,J.PhotoPolymer
Sci.and Tech.,vol.4,135(1991)) 等も用いることがで
きる。Further, as the hole injecting electrode, the ITO film is used in the above embodiment, but other than this, a semitransparent film of gold or the like having a high work function and a high transparency can be used. As the organic hole transport material, the diamine derivative (TPD) shown in Chemical formula 1 above was used, but other various diamine derivatives (Y. Takeshita et.al., Report on Progress
in Polymer Physics in Japan, vol.30, 503 (1987)) and polyvinylcarbazole (T. Fujii et al., J. PhotoPolymer
Sci. And Tech., Vol. 4, 135 (1991)) and the like can also be used.
【００４０】[0040]
【発明の効果】以上説明したように、本発明によれば、
製膜性に優れ、結晶化しにくい縮合多環芳香族基を有す
るオキサジアゾールを複数有したオキサジアゾール系化
合物を、有機電子輸送層の材料として用いることによ
り、電界発光素子の耐久性が向上するという効果を奏し
た。As described above, according to the present invention,
Use of an oxadiazole-based compound that has multiple oxadiazoles with condensed polycyclic aromatic groups that have excellent film-forming properties and that is difficult to crystallize improves the durability of electroluminescent devices by using it as a material for the organic electron transport layer. It has the effect of
【図１】本発明の一例にかかる電界発光素子の断面図で
ある。FIG. 1 is a cross-sectional view of an electroluminescent device according to an example of the present invention.
【図２】電界発光素子１ｍｍ2 当たりの結晶領域の経時
変化を示すグラフである。FIG. 2 is a graph showing a change over time in a crystal region per 1 mm 2 of an electroluminescent device.
１ ガラス基板 ２ ホール注入電極 ３ 有機ホール輸送層 ４ 有機発光層 ５ 有機電子輸送層 ６ 電子注入電極 1 Glass Substrate 2 Hole Injection Electrode 3 Organic Hole Transport Layer 4 Organic Light Emitting Layer 5 Organic Electron Transport Layer 6 Electron Injection Electrode
───────────────────────────────────────────────────── フロントページの続き (72)発明者 藤井 孝則 守口市京阪本通２丁目18番地 三洋電機株 式会社内 (72)発明者 浜田 祐次 守口市京阪本通２丁目18番地 三洋電機株 式会社内 (72)発明者 柴田 賢一 守口市京阪本通２丁目18番地 三洋電機株 式会社内 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takanori Fujii 2-18 Keihan Hondori, Moriguchi Sanyo Electric Co., Ltd. (72) Inventor Yuji Hamada 2-18 Keihan Hondori, Moriguchi Sanyo Electric Co., Ltd. (72) Inventor Kenichi Shibata 2-18 Keihan Hondori, Moriguchi City Sanyo Electric Co., Ltd.
Claims (8)
に、有機ホール輸送層と、有機発光層と、有機電子輸送
層とがホール注入電極側から順に形成された有機３層構
造、或いはホール注入電極と、電子注入電極との間に、
有機発光層と有機電子輸送層とがホール注入電極側から
順に形成された有機２層構造を有する電界発光素子にお
いて、 前記有機電子輸送層には、複数のオキサジアゾール環を
有しており、しかも各々のオキサジアゾール環が縮合多
環芳香族によって置換されているオキサジアゾール系化
合物が用いられていることを特徴とする電界発光素子。1. An organic three-layer structure in which an organic hole transport layer, an organic light emitting layer, and an organic electron transport layer are sequentially formed from a hole injection electrode side between a hole injection electrode and an electron injection electrode, or Between the hole injection electrode and the electron injection electrode,
In an electroluminescent device having an organic two-layer structure in which an organic light emitting layer and an organic electron transporting layer are sequentially formed from the hole injecting electrode side, the organic electron transporting layer has a plurality of oxadiazole rings, Moreover, an electroluminescent device characterized in that an oxadiazole-based compound in which each oxadiazole ring is substituted with a condensed polycyclic aromatic is used.
からなる縮合多環芳香族であることを特徴とする請求項
１記載の電界発光素子。2. The electroluminescent device according to claim 1, wherein the condensed polycyclic aromatic compound is a condensed polycyclic aromatic compound composed of two benzene rings.
からなる縮合多環芳香族であることを特徴とする請求項
１記載の電界発光素子。3. The electroluminescent device according to claim 1, wherein the condensed polycyclic aromatic compound is a condensed polycyclic aromatic compound having three benzene rings.
フェナントレンであることを特徴とする請求項３記載の
電界発光素子。4. The condensed polycyclic aromatic compound is anthracene,
The electroluminescent device according to claim 3, wherein the electroluminescent device is phenanthrene.
からなる縮合多環芳香族であることを特徴とする請求項
１記載の電界発光素子。5. The electroluminescent device according to claim 1, wherein the condensed polycyclic aromatic compound is a condensed polycyclic aromatic compound having four benzene rings.
とを特徴とする請求項５記載の電界発光素子。6. The electroluminescent device according to claim 5, wherein the condensed polycyclic aromatic compound is pyrene.
サジアゾール環の間にベンゼン環を有し、且つ、そのベ
ンゼン環が、オキサジアゾール環の縮合多環芳香族と結
合していない炭素と結合していることを特徴とする請求
項１〜６記載の電界発光素子。7. The oxadiazole-based compound has a benzene ring between oxadiazole rings, and the benzene ring is a carbon not bonded to the condensed polycyclic aromatic ring of the oxadiazole ring. The electroluminescent element according to claim 1, wherein the electroluminescent element is bonded.
サジアゾール環の間にアルキル鎖を有し、且つ、そのア
ルキル鎖が、オキサジアゾール環の縮合多環芳香族と結
合していない炭素と結合していることを特徴とする請求
項１〜６記載の電界発光素子。8. The oxadiazole-based compound has an alkyl chain between oxadiazole rings, and the alkyl chain is a carbon not bonded to the condensed polycyclic aromatic ring of the oxadiazole ring. The electroluminescent element according to claim 1, wherein the electroluminescent element is bonded.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29135892A JP3547769B2 (en) | 1992-10-29 | 1992-10-29 | Electroluminescent device |
| US08/142,970 US5449564A (en) | 1992-10-29 | 1993-10-29 | Organic electroluminescent element having improved durability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29135892A JP3547769B2 (en) | 1992-10-29 | 1992-10-29 | Electroluminescent device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06140156A true JPH06140156A (en) | 1994-05-20 |
| JP3547769B2 JP3547769B2 (en) | 2004-07-28 |
Family
ID=17767895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29135892A Expired - Fee Related JP3547769B2 (en) | 1992-10-29 | 1992-10-29 | Electroluminescent device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3547769B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6803126B2 (en) | 2002-03-15 | 2004-10-12 | Fujitsu Limited | Organic EL element and organic EL display |
| KR100490539B1 (en) * | 2002-09-19 | 2005-05-17 | 삼성에스디아이 주식회사 | Organic electroluminescence device and manufacturing method thereof |
| WO2016035413A1 (en) * | 2014-09-04 | 2016-03-10 | 株式会社Ｊｏｌｅｄ | Display element, display device and electronic apparatus |
-
1992
- 1992-10-29 JP JP29135892A patent/JP3547769B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6803126B2 (en) | 2002-03-15 | 2004-10-12 | Fujitsu Limited | Organic EL element and organic EL display |
| KR100490539B1 (en) * | 2002-09-19 | 2005-05-17 | 삼성에스디아이 주식회사 | Organic electroluminescence device and manufacturing method thereof |
| WO2016035413A1 (en) * | 2014-09-04 | 2016-03-10 | 株式会社Ｊｏｌｅｄ | Display element, display device and electronic apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3547769B2 (en) | 2004-07-28 |
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