JPH05182762A - Organic thin film luminous element - Google Patents
Organic thin film luminous elementInfo
- Publication number
- JPH05182762A JPH05182762A JP3345746A JP34574691A JPH05182762A JP H05182762 A JPH05182762 A JP H05182762A JP 3345746 A JP3345746 A JP 3345746A JP 34574691 A JP34574691 A JP 34574691A JP H05182762 A JPH05182762 A JP H05182762A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- light emitting
- thin film
- substance
- organic thin
- 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.)
- Pending
Links
- 239000010409 thin film Substances 0.000 title claims abstract description 26
- 239000000126 substance Substances 0.000 claims abstract description 38
- 239000000203 mixture Substances 0.000 claims abstract description 3
- 238000002347 injection Methods 0.000 claims description 52
- 239000007924 injection Substances 0.000 claims description 52
- 239000000758 substrate Substances 0.000 abstract description 13
- 239000011521 glass Substances 0.000 abstract description 12
- -1 diamine compound Chemical class 0.000 abstract description 8
- 238000010438 heat treatment Methods 0.000 abstract description 6
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- 150000001875 compounds Chemical class 0.000 abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 2
- 239000013522 chelant Substances 0.000 abstract description 2
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 abstract description 2
- ZPSJGADGUYYRKE-UHFFFAOYSA-N 2H-pyran-2-one Chemical compound O=C1C=CC=CO1 ZPSJGADGUYYRKE-UHFFFAOYSA-N 0.000 abstract 1
- PJANXHGTPQOBST-VAWYXSNFSA-N Stilbene Natural products C=1C=CC=CC=1/C=C/C1=CC=CC=C1 PJANXHGTPQOBST-VAWYXSNFSA-N 0.000 abstract 1
- 235000021286 stilbenes Nutrition 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 120
- 239000010408 film Substances 0.000 description 34
- 239000000463 material Substances 0.000 description 26
- 230000015572 biosynthetic process Effects 0.000 description 7
- 239000011368 organic material Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 239000002356 single layer Substances 0.000 description 5
- 238000007740 vapor deposition Methods 0.000 description 5
- 238000010549 co-Evaporation Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 2
- ZYGHJZDHTFUPRJ-UHFFFAOYSA-N coumarin Chemical compound C1=CC=C2OC(=O)C=CC2=C1 ZYGHJZDHTFUPRJ-UHFFFAOYSA-N 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 238000005036 potential barrier Methods 0.000 description 2
- TVIVIEFSHFOWTE-UHFFFAOYSA-K tri(quinolin-8-yloxy)alumane Chemical compound [Al+3].C1=CN=C2C([O-])=CC=CC2=C1.C1=CN=C2C([O-])=CC=CC2=C1.C1=CN=C2C([O-])=CC=CC2=C1 TVIVIEFSHFOWTE-UHFFFAOYSA-K 0.000 description 2
- DDTHMESPCBONDT-UHFFFAOYSA-N 4-(4-oxocyclohexa-2,5-dien-1-ylidene)cyclohexa-2,5-dien-1-one Chemical class C1=CC(=O)C=CC1=C1C=CC(=O)C=C1 DDTHMESPCBONDT-UHFFFAOYSA-N 0.000 description 1
- 239000005725 8-Hydroxyquinoline Substances 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 229960000956 coumarin Drugs 0.000 description 1
- 235000001671 coumarin Nutrition 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000005401 electroluminescence Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229960003540 oxyquinoline Drugs 0.000 description 1
- WSRHMJYUEZHUCM-UHFFFAOYSA-N perylene-1,2,3,4-tetracarboxylic acid Chemical class C=12C3=CC=CC2=CC=CC=1C1=C(C(O)=O)C(C(O)=O)=C(C(O)=O)C2=C1C3=CC=C2C(=O)O WSRHMJYUEZHUCM-UHFFFAOYSA-N 0.000 description 1
- MCJGNVYPOGVAJF-UHFFFAOYSA-N quinolin-8-ol Chemical compound C1=CN=C2C(O)=CC=CC2=C1 MCJGNVYPOGVAJF-UHFFFAOYSA-N 0.000 description 1
- PYWVYCXTNDRMGF-UHFFFAOYSA-N rhodamine B Chemical compound [Cl-].C=12C=CC(=[N+](CC)CC)C=C2OC2=CC(N(CC)CC)=CC=C2C=1C1=CC=CC=C1C(O)=O PYWVYCXTNDRMGF-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- PJANXHGTPQOBST-UHFFFAOYSA-N stilbene Chemical class C=1C=CC=CC=1C=CC1=CC=CC=C1 PJANXHGTPQOBST-UHFFFAOYSA-N 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
Landscapes
- Electroluminescent Light Sources (AREA)
- Luminescent Compositions (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は有機薄膜発光素子の構
造に係り、特に発光輝度に優れる有機薄膜発光素子に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an organic thin film light emitting device, and more particularly to an organic thin film light emitting device having excellent emission brightness.
【０００２】[0002]
【従来の技術】従来のブラウン管に代わるフラットディ
スプレイの需要の急増に伴い、各種表示素子の開発及び
実用化が精力的に進められている。エレクトロルミネッ
センス素子（以下ＥＬ素子とする）もこうしたニ−ズに
即するものであり、特に全固体の自発発光素子として、
他のディスプレイにはない高解像度及び高視認性により
注目を集めている。現在、実用化されているものは、発
光層にＺｎＳ／Ｍｎ系を用いた無機材料からなるＥＬ素
子である。しかるに、この種の無機ＥＬ素子は発光に必
要な駆動電圧が２００Ｖ程度と高いため駆動方法が複雑
となり製造コストが高いといった問題点がある。また、
青色発光の効率が低いため、フルカラ−化が困難であ
る。これに対して、有機材料を用いた薄膜発光素子は、
発光に必要な駆動電圧が大幅に低減でき、かつ各種発光
物質料の添加によりフルカラ−化の可能性を充分に持つ
ことから、近年研究が活発化している。2. Description of the Related Art With the rapid increase in demand for flat displays replacing conventional cathode ray tubes, various display elements have been vigorously developed and put into practical use. An electroluminescence element (hereinafter referred to as an EL element) is also adapted to such a need, and in particular, as an all solid state spontaneous light emitting element,
It attracts attention due to its high resolution and high visibility that other displays do not have. At present, what has been put into practical use is an EL element made of an inorganic material using a ZnS / Mn-based light emitting layer. However, this type of inorganic EL element has a problem that the driving method is complicated and the manufacturing cost is high because the driving voltage required for light emission is as high as about 200V. Also,
Since the efficiency of blue light emission is low, it is difficult to achieve full color. On the other hand, the thin film light emitting device using the organic material is
Since the driving voltage required for light emission can be significantly reduced and the addition of various light-emitting substance materials has a sufficient possibility of full-coloring, research has been activated in recent years.
【０００３】正孔注入層／発光層／電極からなる積層型
において、発光物質にトリス（８−ヒドロキシキノリ
ン）アルミニウムを、正孔注入物質に１，１’−ビス
（４−Ｎ，Ｎ−ジトリアミノフェニル）シクロヘキサン
を用いることにより、１０Ｖ以下の印加電圧で１０００
ｃｄ／ｍ2 以上の輝度が得られたという報告がなされて
以来開発に拍車がかけられた。（Appl.Phys.Lett．51,9
13,(1987)) 図４は従来の有機薄膜発光素子を示す断面図である。図
５は従来の異なる有機薄膜発光素子を示す断面図であ
る。ガラス等の絶縁性透明基板１上に、インジウムスズ
酸化物（以下ＩＴＯと称する）、酸化スズ（以下ＳｎＯ
2 と称する）等の透明導電膜からなる正極２を形成し、
正孔注入層３、発光層５と順次有機膜を成膜する。最後
に負極８として、Ｍｇ、Ａｌ、Ｉｎ等の膜を形成する。
図５は、発光層中への電子注入を向上させて、発光効率
を向上させることを意図して提案された、電子注入層を
含む３層構造素子の例である。ガラス等の絶縁性透明基
板１上に、ＩＴＯ等の透明導電膜からなる正極２を形成
し、正孔注入層３、発光層５、電子注入層７の３層を成
膜する。最後に負極８として、Ｍｇ、Ａｌ、Ｉｎ等の膜
を形成する。In a layered type composed of a hole injecting layer / a light emitting layer / an electrode, tris (8-hydroxyquinoline) aluminum is used as a light emitting substance and 1,1′-bis (4-N, N-ditril) is used as a hole injecting substance. By using aminophenyl) cyclohexane, 1000 is applied at an applied voltage of 10 V or less.
The development has been spurred since it was reported that a brightness of cd / m 2 or more was obtained. (Appl.Phys.Lett. 51 , 9
13, (1987)) FIG. 4 is a sectional view showing a conventional organic thin film light emitting device. FIG. 5 is a cross-sectional view showing another conventional organic thin film light emitting device. On an insulative transparent substrate 1 such as glass, indium tin oxide (hereinafter referred to as ITO), tin oxide (hereinafter SnO).
2 ) is formed of a transparent conductive film such as
An organic film is sequentially formed on the hole injection layer 3 and the light emitting layer 5. Finally, a film of Mg, Al, In or the like is formed as the negative electrode 8.
FIG. 5 shows an example of a three-layer structure device including an electron injection layer, which is proposed with the intention of improving electron injection into the light emitting layer to improve light emission efficiency. A positive electrode 2 made of a transparent conductive film such as ITO is formed on an insulating transparent substrate 1 such as glass, and three layers of a hole injection layer 3, a light emitting layer 5 and an electron injection layer 7 are formed. Finally, a film of Mg, Al, In or the like is formed as the negative electrode 8.
【０００４】[0004]
【発明が解決しようとする課題】この様に、有機材料を
用いた薄膜発光素子は低電圧駆動やフルカラ−化の可能
性等を強く示唆しており、今後素子構造の改良、有機材
料の開発等により、より一層の低電圧化と多色発光化を
図っていく必要がある。一方実用化に向けての重要課題
として安定性の大幅な向上がある。特に１万時間程度の
長時間駆動に伴う特性劣化の問題は乗り越えなければな
らないハ−ドルである。また該有機薄膜の膜厚は１μｍ
以下であるため、成膜性が良好でピンホ−ル等の電気的
欠陥のない材料の開発も必要である。さらには、量産性
の観点から、大量製造が容易で安価な有機材料の開発や
素子形成方法の改良等も重要な技術課題である。この発
明は上述の点に鑑みてなされ、その目的は、発光層と電
荷注入層の界面の構造に改良を加えることにより、低い
印加電圧で発光輝度に優れる有機薄膜発光素子を提供す
ることにある。As described above, the thin-film light-emitting device using an organic material strongly suggests the possibility of low voltage driving and full colorization, and the improvement of the device structure and the development of organic materials in the future. Therefore, it is necessary to further reduce the voltage and achieve multicolor emission. On the other hand, significant improvement in stability is an important issue for practical application. In particular, the problem of characteristic deterioration due to long-time driving of about 10,000 hours is a hardware that must be overcome. The thickness of the organic thin film is 1 μm
Because of the following, it is also necessary to develop a material having good film-forming properties and free from electrical defects such as pinholes. Further, from the viewpoint of mass productivity, development of an organic material which is easy to mass-produce and is inexpensive, improvement of a device forming method, and the like are important technical subjects. The present invention has been made in view of the above points, and an object thereof is to provide an organic thin film light emitting device having excellent emission luminance at a low applied voltage by improving the structure of the interface between the light emitting layer and the charge injection layer. ..
【０００５】[0005]
【課題を解決するための手段】上述の目的はこの発明に
よれば、発光層と，混合層と、電荷注入層を有し、発光
層は注入された正孔と電子の両電荷を再結合させて所定
の波長の発光を行うものであり、電荷注入層は電荷を発
光層に注入するものであり、混合層は発光層と電荷注入
層に挟まれた層で、発光物質と電荷注入物質とを所定の
割合で混合してなるとすることにより達成される。該混
合層は、両材料の混合比を一定にした単層または混合比
を変えた複数の層からなる多段構造とし、かつ該複数層
は発光層から電荷注入層に向かって、しだいに層中に含
まれる発光物質の混合比を小さくしたものとする。According to the present invention, the above-mentioned object has a light emitting layer, a mixed layer, and a charge injection layer, and the light emitting layer recombines the injected charges of both holes and electrons. The charge injection layer is for injecting charges into the light emitting layer, and the mixed layer is a layer sandwiched between the light emitting layer and the charge injection layer. It is achieved by mixing and at a predetermined ratio. The mixed layer has a single-layer structure having a constant mixing ratio of both materials or a multi-stage structure composed of a plurality of layers having different mixing ratios, and the plurality of layers are gradually formed in the layers from the light emitting layer toward the charge injection layer. It is assumed that the mixing ratio of the light emitting substance contained in is reduced.
【０００６】[0006]
【作用】混合層を用いると、電荷注入層から発光層への
電荷の注入性が向上するものと推定される。It is presumed that the use of the mixed layer improves the property of injecting charges from the charge injection layer to the light emitting layer.
【０００７】[0007]
【実施例】次にこの発明の実施例を図面に基づいて説明
する。本発明における有機膜は、一般的に抵抗加熱蒸着
法を用いて形成される。正孔注入物質には、前記の１，
１’−ビス（４−Ｎ，Ｎ−ジトリアミノフェニル）シク
ロヘキサン等のジアミン系化合物、スチルベン化合物等
が使用されている。化１に代表的な正孔注入物質の構造
式を示す。良好な発光特性を得るための該正孔注入層の
膜厚は２００〜２０００Å、好適には３００〜８００Å
である。発光物質としては，前記トリス（８−ヒドロキ
シキノリン）アルミニウム等の金属キレ−ト化合物や、
ロ−ダミン、クマリン等各種色素が使用されている。化
２に代表的な発光物質の構造式を示す。良好な発光特性
を得るための該発光層の膜厚は２００〜２０００Å、好
適には、３００〜８００Åである。電子注入物質として
は、ペリレンテトラカルボン酸誘導体、ジフェノキノン
系化合物が使用されている。化３に、代表的な電子注入
物質の構造式を示す。良好な発光特性を得るための該電
子注入層の膜厚は２００〜２０００Å、好適には、３０
０〜８００Åである。Embodiments of the present invention will now be described with reference to the drawings. The organic film in the present invention is generally formed by a resistance heating vapor deposition method. The hole-injecting substance includes the above-mentioned 1,
Diamine compounds such as 1′-bis (4-N, N-ditriaminophenyl) cyclohexane and stilbene compounds are used. Chemical formula 1 shows a structural formula of a typical hole injecting material. The film thickness of the hole injection layer for obtaining good emission characteristics is 200 to 2000Å, preferably 300 to 800Å
Is. As the luminescent substance, a metal chelate compound such as tris (8-hydroxyquinoline) aluminum,
Various dyes such as rhodamine and coumarin are used. Chemical formula 2 shows a structural formula of a typical luminescent material. The film thickness of the light emitting layer for obtaining good light emitting characteristics is 200 to 2000Å, preferably 300 to 800Å. Perylene tetracarboxylic acid derivatives and diphenoquinone compounds are used as electron injecting substances. Chemical formula 3 shows a structural formula of a typical electron-injecting substance. The film thickness of the electron injection layer for obtaining good light emission characteristics is 200 to 2000Å, preferably 30.
It is 0 to 800Å.
【０００８】[0008]
【化１】 [Chemical 1]
【０００９】[0009]
【化２】 [Chemical 2]
【００１０】[0010]
【化３】 [Chemical 3]
【００１１】一方、本発明における混合層に関しては、
前記の如く、正孔注入物質と発光物質からなる場合と発
光物質と電子注入物質からなる場合がある。いずれの場
合も、真空蒸着装置内の２つの蒸着ターゲットを使っ
て、該２種の有機材料を共蒸着することにより形成す
る。前述の様に、該混合層の作用については明確に解明
されていないが、正孔注入層から発光層への正孔の注入
性または電子注入層から発光層への電子の注入性の向上
と推定される。すなわち、従来の素子においては、正孔
注入層と発光層間または電子注入層と発光層間に生じる
電位障壁により、正孔注入層または電子注入層から発光
層への正孔または電子の注入が制限されるものと考えら
れ、これに対して、該混合層の設置により両層の電位障
壁を和らげ、正孔または電子の注入性向上につながるも
のと考えられる。また、該混合層の構造としては、前述
の様に混合比率を一定とした単層とするか、あるいはよ
り好ましいものとして、混合比率の異なる複数個の層か
らなり，かつ該複数個の層が発光層界面に位置する層か
ら順に、層中に含まれる発光物質の混合比を小さくして
いくものとする。On the other hand, regarding the mixed layer in the present invention,
As described above, it may be composed of the hole injecting material and the light emitting material, or may be composed of the light emitting material and the electron injecting material. In any case, it is formed by co-evaporating the two types of organic materials by using two vapor deposition targets in a vacuum vapor deposition apparatus. As described above, although the function of the mixed layer has not been clearly clarified, it is possible to improve the property of injecting holes from the hole injection layer to the light emitting layer or the property of injecting electrons from the electron injection layer to the light emitting layer. Presumed. That is, in the conventional device, the potential barrier generated between the hole injection layer and the light emitting layer or between the electron injection layer and the light emitting layer restricts the injection of holes or electrons from the hole injection layer or the electron injection layer to the light emitting layer. On the other hand, it is considered that the installation of the mixed layer softens the potential barriers of both layers and improves the injectability of holes or electrons. The structure of the mixed layer is a single layer having a constant mixing ratio as described above, or more preferably, it is composed of a plurality of layers having different mixing ratios, and the plurality of layers are It is assumed that the mixing ratio of the light emitting substances contained in the layer is decreased in order from the layer located at the interface of the light emitting layer.
【００１２】該混合層における正孔注入物質と発光物質
または電子注入物質と発光物質の混合比率は、使用する
材料物質により最適範囲が若干異なるが、上記単層の場
合は該混合層全体に占める発光物質の重量比率が２０〜
８０％が好適であった。また、該混合層の膜厚について
も使用する材料物質により最適範囲が若干異なるが、２
０〜７０Åが好適であった。これ以上厚くするとかえっ
て駆動電圧の上昇を招く。この原因についての詳細は不
明であるが、該混合層中に存在する捕獲準位等に正孔注
入層からの正孔または電子注入層からの電子が捕獲され
るものと推定される。なお、該混合層が混合比率の異な
る複数個の層からなる場合は、該混合層全体の膜厚の最
適範囲は単層の場合と同様に２０〜７０Åが好適であっ
た。該構造の具体的な構成例としては、３層からなり、
発光層界面側に位置する層より電荷注入層界面に位置す
る層に向かって順に発光物質の混合比率を、８０％，５
０％，２０％としたものである。The mixing ratio of the hole injecting substance and the light emitting substance or the electron injecting substance and the light emitting substance in the mixed layer is slightly different depending on the material used, but in the case of the above single layer, it occupies the whole mixed layer. Weight ratio of luminescent material is 20 ~
80% was suitable. Also, regarding the film thickness of the mixed layer, the optimum range is slightly different depending on the material used, but 2
0 to 70Å was suitable. If the thickness is made thicker than this, the drive voltage is rather increased. Although the details of this cause are unknown, it is presumed that holes from the hole injection layer or electrons from the electron injection layer are trapped by the trap levels and the like existing in the mixed layer. When the mixed layer was composed of a plurality of layers having different mixing ratios, the optimum range of the total thickness of the mixed layer was 20 to 70Å as in the case of a single layer. As a concrete configuration example of the structure, it is composed of three layers,
The mixing ratio of the luminescent materials is set to 80%, 5% from the layer located on the light emitting layer interface side toward the layer located on the charge injection layer interface.
It is set to 0% and 20%.
【００１３】実施例１ 図１は、この発明の実施例に係る有機薄膜発光素子を示
す断面図である。５０ｍｍ角のガラス基板１上、ＩＴＯ
を〜２０００Å形成した後、該ＩＴＯガラス基板を抵抗
加熱蒸着装置内にセットし、正孔注入層３、正孔注入物
質／発光物質混合層４、発光層５と順次成膜した。成膜
に際して真空槽内は６ｘ１０-6Ｔｏｒｒまで減圧した。
正孔注入層には、前記正孔注入物質のうち化学式（6-2
）で示される化合物を用い、ボ−ト温度１５０0 Ｃ〜
１８０0 Ｃの範囲で加熱し成膜速度を２Å／ｓとして６
００Å形成した。混合層には、該注入物質（6-2 ）と、
発光物質としての前記した（８−ヒドロキシキノリン）
アルミニウムを使って、共蒸着により形成した。該混合
層中の正孔注入物質（6-2 ）の混合層全体に占める重量
比率は５０％とし、該混合層の膜厚は５０Åとした。な
お、共蒸着時のト−タルの成膜速度は３Å／ｓとし、両
有機材料の成膜速度を調整することにより、上記混合比
率の膜を形成した。発光層には、上記の（８−ヒドロキ
シキノリン）アルミニウムを用いて、ボ−ト温度２５０
〜３５０0 Ｃの範囲で加熱し、成膜速度を２Å／ｓとし
て６００Å形成した。この後、試料を真空槽から取り出
し、直径５ｍｍのドットパタ−ンからなるステンレス製
マスクを取りつけ、新たに抵抗加熱蒸着装置内にセット
し負極８としてＭｇ／Ａｇ（１０：１の比率）を１５０
０Å形成した。上述の混合層は組成が一定の単一層であ
るが、発光物質の重量比が７０％で膜厚が３０Åの層と
発光物質の重量比が３０％で膜厚が３０Åの膜とを積層
した多段構造とすることもできる。Example 1 FIG. 1 is a sectional view showing an organic thin film light emitting device according to an example of the present invention. ITO on a glass substrate 1 of 50 mm square
To 2000 Å, the ITO glass substrate was set in a resistance heating vapor deposition apparatus, and a hole injection layer 3, a hole injection substance / light emitting substance mixed layer 4, and a light emitting layer 5 were sequentially formed. During film formation, the pressure inside the vacuum chamber was reduced to 6 × 10 −6 Torr.
The hole injection layer has a chemical formula (6-2
The compounds used represented by), Bo - DOO temperature 0.99 0 Celsius to
Heated in the range of 180 0 C and set the film formation rate to 2Å / s. 6
00Å formed. In the mixed layer, the injected substance (6-2) and
The above-mentioned (8-hydroxyquinoline) as a luminescent substance
It was formed by co-evaporation using aluminum. The weight ratio of the hole injection material (6-2) in the mixed layer to the whole mixed layer was 50%, and the film thickness of the mixed layer was 50Å. The total film formation rate during co-evaporation was 3Å / s, and the film having the above mixing ratio was formed by adjusting the film formation rates of both organic materials. For the light emitting layer, the above (8-hydroxyquinoline) aluminum is used and the boat temperature is 250.
It was heated in the range of to 350 0 C, was 600Å formed a deposition rate of 2 Å / s. After that, the sample was taken out from the vacuum chamber, a stainless mask made of a dot pattern with a diameter of 5 mm was attached, and the sample was newly set in the resistance heating vapor deposition device, and Mg / Ag (ratio of 10: 1) was set to 150 as the negative electrode 8.
0Å formed. The above-mentioned mixed layer is a single layer having a constant composition, but a layer having a weight ratio of luminescent material of 70% and a film thickness of 30Å and a film having a weight ratio of luminescent material of 30% and a film thickness of 30Å are laminated. It can also have a multi-stage structure.
【００１４】比較例１ 図４に示した様に、ガラス基板上にＩＴＯを形成した
後、正孔注入層、発光層と順次有機膜を蒸着し、最後に
負極としてＭｇ／Ａｇ（１０：１の比率）を形成した。
なお各層の材料、膜厚、成膜条件はすべて上記実施例１
と同一とした。本実施例１と比較例１の素子について直
流電圧を印加したところ、両者ともに緑色（発光中心波
長：５５０ｎｍ）の均一な発光が得られた。発光特性に
おいて、比較例１の素子では、１０００ｃｄ／ｍ2 の輝
度を得るのに、１２．３Ｖの駆動電圧を必要としたのに
対して、実施例１の素子では８．２Ｖとなり、駆動電圧
の低減が図れた。Comparative Example 1 As shown in FIG. 4, after forming ITO on a glass substrate, an organic film was sequentially deposited on a hole injecting layer and a light emitting layer, and finally as a negative electrode Mg / Ag (10: 1). Ratio).
The material, film thickness, and film forming conditions of each layer are all the same as those in the first embodiment.
Same as. When a DC voltage was applied to the elements of Example 1 and Comparative Example 1, uniform green (luminescence center wavelength: 550 nm) light emission was obtained for both. Regarding the light emission characteristics, the device of Comparative Example 1 required a drive voltage of 12.3 V to obtain a luminance of 1000 cd / m 2 , whereas the device of Example 1 required a drive voltage of 8.2 V, which was a drive voltage. Was reduced.
【００１５】実施例２ 図２は、この発明の異なる実施例に係る有機薄膜発光素
子を示す断面図である。５０ｍｍ角のガラス基板１上に
正極２として、ＩＴＯを〜２０００Å形成した後、該Ｉ
ＴＯつきガラス基板を実施例１と同様に真空装置内にセ
ットし、正孔注入層３、発光層５、発光物質／電子注入
物質混合層６、電子注入層７と順次成膜し、最後に負極
８としてＭｇ／Ａｇ（１０：１の比率）を形成した。混
合層には、発光物質として上記の（８−ヒドロキシキノ
リン）アルミニウムと、電子注入物質として、化学式
（８−２）で示される化合物を用いて、共蒸着により成
膜した。該混合層中の電子注入物質（８−２）の混合層
全体に占める重量比率は５０％とし、該混合層の膜厚は
５０Åとした。なお、共蒸着時のト−タルの成膜速度は
３Å／ｓとし、両有機材料の成膜速度を調整することに
より上記混合比率の膜を形成した。電子注入層には、同
様に該電子注入物質（８−２）を用いて、ボ−ト加熱温
度３００℃、成膜速度３Å／ｓにて、４００Å成膜し
た。他の各層についてはすべて実施例１と同一材料、同
一膜厚、同一成膜条件とした。Embodiment 2 FIG. 2 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention. After forming ITO to 2000 Å as the positive electrode 2 on the glass substrate 1 of 50 mm square, the I
A glass substrate with TO was set in a vacuum apparatus as in Example 1, and the hole injection layer 3, the light emitting layer 5, the light emitting material / electron injection material mixed layer 6, and the electron injection layer 7 were sequentially formed. Finally, Mg / Ag (ratio of 10: 1) was formed as the negative electrode 8. The mixed layer was formed by co-evaporation using the above-mentioned (8-hydroxyquinoline) aluminum as a light emitting substance and the compound represented by the chemical formula (8-2) as an electron injecting substance. The weight ratio of the electron injecting substance (8-2) in the mixed layer to the entire mixed layer was 50%, and the film thickness of the mixed layer was 50Å. The total film formation rate during co-evaporation was set to 3Å / s, and a film having the above mixing ratio was formed by adjusting the film formation rates of both organic materials. Similarly, the electron injection material (8-2) was used for the electron injection layer to form a 400 Å film at a boat heating temperature of 300 ° C and a film formation rate of 3 Å / s. All the other layers were made of the same material, the same film thickness, and the same film forming conditions as in Example 1.
【００１６】実施例３ 図３は、この発明のさらに異なる実施例に係る有機薄膜
発光素子を示す断面図である。５０ｍｍ角のガラス基板
１上に正極２として、ＩＴＯを〜２０００Å形成した
後、該ＩＴＯつきガラス基板を 実施例１と同様に真空
装置内にセットし、正孔注入層３、正孔注入物質／発光
物質混合層４、発光層５，発光物質／電子注入物質混合
層６、電子注入層７と順次成膜し、最後に負極８として
Ｍｇ／Ａｇ（１０：１の比率）を形成した。各層の材
料、膜厚、成膜条件はすべて上記実施例１、実施例２と
同一とした。Embodiment 3 FIG. 3 is a cross-sectional view showing an organic thin film light emitting device according to still another embodiment of the present invention. After forming ITO up to 2000 Å as the positive electrode 2 on the glass substrate 1 of 50 mm square, the glass substrate with ITO was set in a vacuum apparatus as in Example 1, and the hole injection layer 3, hole injection material / The light emitting material mixed layer 4, the light emitting layer 5, the light emitting material / electron injection material mixed layer 6, and the electron injection layer 7 were sequentially formed, and finally Mg / Ag (ratio of 10: 1) was formed as the negative electrode 8. The material of each layer, the film thickness, and the film forming conditions were all the same as those in the above-described first and second embodiments.
【００１７】比較例２ 図５に示した様に、ガラス基板上にＩＴＯを形成した
後、正孔注入層、発光層、電子注入層と順次有機膜を蒸
着し、最後に負極としてＭｇ／Ａｇ（１０：１の比率）
を形成した。なお各層の膜厚、成膜条件はすべて上記実
施例２と同一とした。本実施例２、実施例３と比較例２
の素子について直流電圧を印加したところ、３者ともに
緑色（発光中心波長：５５０ｎｍ）の均一な発光が得ら
れた。発光特性において、比較例２の素子では、１００
０ｃｄ／ｍ2 の輝度を得るのに、１１．７Ｖの駆動電圧
を必要としたのに対して、実施例２の素子では７．６
Ｖ、実施例３の素子では７．１Ｖとなり、駆動電圧の低
減が図れた。Comparative Example 2 As shown in FIG. 5, after forming ITO on a glass substrate, an organic film was sequentially deposited on a hole injection layer, a light emitting layer and an electron injection layer, and finally as a negative electrode Mg / Ag. (10: 1 ratio)
Formed. The thickness of each layer and the film forming conditions were all the same as in Example 2 above. Examples 2 and 3 and Comparative Example 2
When a DC voltage was applied to the device of No. 3, uniform emission of green light (emission center wavelength: 550 nm) was obtained for all three devices. With respect to the light emission characteristics, the device of Comparative Example 2 has a light emitting property of 100.
A driving voltage of 11.7 V was required to obtain a luminance of 0 cd / m 2 , whereas the device of Example 2 had a driving voltage of 7.6.
V, 7.1 V in the element of Example 3, and the drive voltage could be reduced.
【００１８】[0018]
【発明の効果】この発明によれば発光層と，混合層と、
電荷注入層を有し、発光層は注入された正孔と電子の両
電荷を再結合させて所定の波長の発光を行うものであ
り、電荷注入層は電荷を発光層に注入するものであり、
混合層は発光層と電荷注入層に挟まれた層で、発光物質
と電荷注入物質とを所定の割合で混合してなるので低い
印加電圧で発光輝度に優れる有機薄膜発光素子が得られ
る。According to the present invention, the light emitting layer, the mixed layer,
It has a charge injection layer, the light emitting layer recombines both the injected charges of holes and electrons to emit light of a predetermined wavelength, and the charge injection layer injects charges into the light emitting layer. ,
The mixed layer is a layer sandwiched between the light emitting layer and the charge injection layer, and is formed by mixing the light emitting substance and the charge injection substance at a predetermined ratio, and thus an organic thin film light emitting device having excellent emission brightness can be obtained at a low applied voltage.
【図１】この発明の実施例に係る有機薄膜発光素子を示
す断面図FIG. 1 is a cross-sectional view showing an organic thin film light emitting device according to an embodiment of the invention.
【図２】この発明の異なる実施例に係る有機薄膜発光素
子を示す断面図FIG. 2 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention.
【図３】この発明のさらに異なる実施例に係る有機薄膜
発光素子を示す断面図FIG. 3 is a sectional view showing an organic thin film light emitting device according to another embodiment of the present invention.
【図４】従来の有機薄膜発光素子を示す断面図FIG. 4 is a cross-sectional view showing a conventional organic thin film light emitting device.
【図５】従来の異なる有機薄膜発光素子を示す断面図FIG. 5 is a cross-sectional view showing a different conventional organic thin film light emitting device.
１ ガラス基板 ２ 正極 ３ 正孔注入層 ４ 混合層 ５ 発光層 ６ 混合層 ７ 電子注入層 ８ 負極 ９ 直流電源 1 Glass Substrate 2 Positive Electrode 3 Hole Injection Layer 4 Mixed Layer 5 Light Emitting Layer 6 Mixed Layer 7 Electron Injection Layer 8 Negative Electrode 9 DC Power Supply
Claims (6)
所定の波長の発光を行うものであり、 電荷注入層は電荷を発光層に注入するものであり、 混合層は発光層と電荷注入層に挟まれた層で、発光物質
と電荷注入物質とを所定の割合で混合してなることを特
徴とする有機薄膜発光素子。1. A light emitting layer, a mixed layer, and a charge injection layer, wherein the light emitting layer recombines both the injected charges of holes and electrons to emit light of a predetermined wavelength. The injection layer is for injecting charges into the light emitting layer, and the mixed layer is a layer sandwiched between the light emitting layer and the charge injection layer, and is characterized by mixing the light emitting substance and the charge injection substance in a predetermined ratio. Organic thin film light emitting device.
て、電荷注入層は正孔注入層であることを特徴とする有
機薄膜発光素子。2. The organic thin film light emitting device according to claim 1, wherein the charge injection layer is a hole injection layer.
て、電荷注入層は電子注入層であることを特徴とする有
機薄膜発光素子。3. The organic thin film light emitting device according to claim 1, wherein the charge injection layer is an electron injection layer.
て、混合層における発光物質の含有割合は２０ないし８
０重量％の範囲にあることを特徴とする有機薄膜発光素
子。4. The organic thin film light emitting device according to claim 1, wherein the content ratio of the light emitting substance in the mixed layer is 20 to 8.
An organic thin film light emitting device characterized by being in a range of 0% by weight.
て、混合層の膜厚は２０ないし７０Åの範囲にあること
を特徴とする有機薄膜発光素子。5. The organic thin film light emitting device according to claim 1, wherein the thickness of the mixed layer is in the range of 20 to 70Å.
て、混合層はその組成を異にする複数の層の多段構造で
あることを特徴とする有機薄膜発光素子。6. The organic thin film light emitting device according to claim 1, wherein the mixed layer has a multi-stage structure of a plurality of layers having different compositions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3345746A JPH05182762A (en) | 1991-12-27 | 1991-12-27 | Organic thin film luminous element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3345746A JPH05182762A (en) | 1991-12-27 | 1991-12-27 | Organic thin film luminous element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05182762A true JPH05182762A (en) | 1993-07-23 |
Family
ID=18378694
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3345746A Pending JPH05182762A (en) | 1991-12-27 | 1991-12-27 | Organic thin film luminous element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05182762A (en) |
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- 1991-12-27 JP JP3345746A patent/JPH05182762A/en active Pending
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| JP2017103224A (en) * | 2015-11-30 | 2017-06-08 | エルジー ディスプレイ カンパニー リミテッド | Organic light emitting diode, organic electroluminescent display comprising the same, and method of manufacturing organic light emitting diode |
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