JPH10340787A - Organic electroluminescent element and its manufacture - Google Patents
Organic electroluminescent element and its manufactureInfo
- Publication number
- JPH10340787A JPH10340787A JP9151001A JP15100197A JPH10340787A JP H10340787 A JPH10340787 A JP H10340787A JP 9151001 A JP9151001 A JP 9151001A JP 15100197 A JP15100197 A JP 15100197A JP H10340787 A JPH10340787 A JP H10340787A
- Authority
- JP
- Japan
- Prior art keywords
- cathode
- work function
- thin film
- insulating film
- substrate
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 239000010408 film Substances 0.000 claims abstract description 32
- 239000010409 thin film Substances 0.000 claims abstract description 28
- 239000000758 substrate Substances 0.000 claims abstract description 21
- 239000000463 material Substances 0.000 claims abstract description 19
- 238000002347 injection Methods 0.000 claims abstract description 15
- 239000007924 injection Substances 0.000 claims abstract description 15
- 230000001590 oxidative effect Effects 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 14
- 229910052751 metal Inorganic materials 0.000 abstract description 12
- 239000002184 metal Substances 0.000 abstract description 12
- 230000003647 oxidation Effects 0.000 abstract description 6
- 238000007254 oxidation reaction Methods 0.000 abstract description 6
- 150000002739 metals Chemical class 0.000 abstract description 5
- 229910052737 gold Inorganic materials 0.000 abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 abstract description 3
- 230000006866 deterioration Effects 0.000 abstract description 3
- 230000001629 suppression Effects 0.000 abstract description 2
- 238000009413 insulation Methods 0.000 abstract 2
- 229910018404 Al2 O3 Inorganic materials 0.000 abstract 1
- 239000000243 solution Substances 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 21
- 230000005525 hole transport Effects 0.000 description 7
- 230000004888 barrier function Effects 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 239000012535 impurity Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 108091008695 photoreceptors Proteins 0.000 description 2
- -1 quinolyl aluminum Chemical compound 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000002344 surface layer Substances 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
- 238000001771 vacuum deposition Methods 0.000 description 2
- KLCLIOISYBHYDZ-UHFFFAOYSA-N 1,4,4-triphenylbuta-1,3-dienylbenzene Chemical class C=1C=CC=CC=1C(C=1C=CC=CC=1)=CC=C(C=1C=CC=CC=1)C1=CC=CC=C1 KLCLIOISYBHYDZ-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- XZCJVWCMJYNSQO-UHFFFAOYSA-N butyl pbd Chemical compound C1=CC(C(C)(C)C)=CC=C1C1=NN=C(C=2C=CC(=CC=2)C=2C=CC=CC=2)O1 XZCJVWCMJYNSQO-UHFFFAOYSA-N 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 150000004985 diamines Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004770 highest occupied molecular orbital Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 238000004768 lowest unoccupied molecular orbital Methods 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- MACHGYNFLRLMEV-UHFFFAOYSA-N n-[4-(4-aminophenyl)phenyl]-3-methyl-n-(3-methylphenyl)aniline Chemical compound CC1=CC=CC(N(C=2C=CC(=CC=2)C=2C=CC(N)=CC=2)C=2C=C(C)C=CC=2)=C1 MACHGYNFLRLMEV-UHFFFAOYSA-N 0.000 description 1
- 125000001715 oxadiazolyl group Chemical group 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- 230000005641 tunneling Effects 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/80—Constructional details
- H10K50/805—Electrodes
- H10K50/82—Cathodes
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Electroluminescent Light Sources (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、有機発光素子及び
その製造方法に関する。更に詳しくは、本発明は、耐久
性に優れ、発光効率の高い、キャリア注入型の有機発光
素子及びその製造方法に関する。The present invention relates to an organic light emitting device and a method for manufacturing the same. More specifically, the present invention relates to a carrier-injection type organic light-emitting device having excellent durability and high luminous efficiency, and a method for manufacturing the same.
【０００２】[0002]
【従来の技術】従来の代表的な有機発光素子としては、
ガラス基板上に、ＩＴＯ透明電極（陽極）／ホール輸送
性有機薄膜（ホール輸送層）／発光性有機薄膜（発光
層）／電子輸送性有機薄膜（電子輸送層）／ＭｇＡｇ共
蒸着膜（陰極）を順次積層した構造が知られている。2. Description of the Related Art Conventional typical organic light emitting devices include:
ITO transparent electrode (anode) / Hole transporting organic thin film (Hole transporting layer) / Emitting organic thin film (Emitting layer) / Electron transporting organic thin film (Electron transporting layer) / MgAg co-deposited film (Cathode) on glass substrate Are known.
【０００３】また、特開平５−３０８０号公報では、有
機薄膜上にＭｇＯ等の金属酸化膜を形成してからＭｇ等
の陰極を積層することによって、キャリアの閉じ込め効
果を向上させた有機発光素子が記載されている。In Japanese Patent Application Laid-Open No. Hei 5-3080, an organic light-emitting device in which a metal oxide film such as MgO is formed on an organic thin film and a cathode such as Mg is laminated thereon to improve the effect of confining carriers. Is described.
【０００４】[0004]
【発明が解決しようとする課題】従来（上記公報におい
ても）、陰極から有機薄膜への電子注入効率を高めるた
め、ＭｇやＬｉ等の仕事関数の低い金属を陰極に使用し
ていた（上記公報では４ｅＶ以下）。しかしながら、こ
れらの金属は化学的に不安定であるため、酸化等により
経時変化が生じ、有機発光素子の特性が劣化するという
問題があった。Heretofore (also in the above publication), a metal having a low work function, such as Mg or Li, has been used for the cathode in order to increase the efficiency of electron injection from the cathode into the organic thin film (see the above publication). 4 eV or less). However, since these metals are chemically unstable, they change with time due to oxidation or the like, and there is a problem that the characteristics of the organic light emitting device are deteriorated.
【０００５】また、上記公報では、有機薄膜と陰極の間
への金属酸化膜の形成は、真空チャンバー内に酸素や水
分を導入して、蒸着中に陰極材料を酸化させることによ
り行われている。しかし、この方法では、有機薄膜も酸
素や水分に晒されることとなるので、有機薄膜が変質
し、注入特性が劣化すると共に素子特性も劣化する恐れ
があった。In the above publication, the formation of a metal oxide film between an organic thin film and a cathode is performed by introducing oxygen or moisture into a vacuum chamber and oxidizing the cathode material during vapor deposition. . However, in this method, since the organic thin film is also exposed to oxygen and moisture, the organic thin film may be deteriorated, and the injection characteristics and the device characteristics may be deteriorated.
【０００６】[0006]
【課題を解決するための手段】本発明の発明者は、化学
的に安定な陰極を使用することにより素子特性の劣化を
抑え、かつ陰極から有機薄膜への電子の注入を容易にし
て発光効率を高めることを目的として検討した結果、本
発明に至った。かくして本発明によれば、少なくとも基
板、仕事関数が４ｅＶより大きな材料からなる陰極、絶
縁膜、有機薄膜及び陽極により構成され、かつキャリア
注入型であることを特徴とする有機発光素子が提供され
る。Means for Solving the Problems The inventor of the present invention uses a chemically stable cathode to suppress the deterioration of the device characteristics and to facilitate the injection of electrons from the cathode into the organic thin film to improve the luminous efficiency. As a result of study for the purpose of increasing the value, the present invention was reached. Thus, according to the present invention, there is provided an organic light emitting device comprising at least a substrate, a cathode, an insulating film, an organic thin film, and an anode made of a material having a work function larger than 4 eV, and being of a carrier injection type. .
【０００７】また、本発明によれば、基板上に、仕事関
数が４ｅＶより大きな材料からなる陰極、絶縁膜、有機
薄膜及び陽極をこの順で形成することを特徴とするキャ
リア注入型の有機発光素子の製造方法が提供される。According to the present invention, a carrier injection type organic light emitting device is characterized in that a cathode, an insulating film, an organic thin film and an anode made of a material having a work function larger than 4 eV are formed in this order on a substrate. A method for manufacturing a device is provided.
【０００８】[0008]
【発明の実施の形態】本発明を、図１に示す有機発光素
子の概略断面図に基づき説明する。ただし、図１は、本
発明の説明を目的とするものであり、本発明はこの構成
に限定されることはない。まず、基板１上に陰極２を形
成する。本発明に使用できる基板としては、ガラス基
板、石英基板、シリコン基板等が挙げられる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to a schematic sectional view of an organic light emitting device shown in FIG. However, FIG. 1 is for the purpose of describing the present invention, and the present invention is not limited to this configuration. First, the cathode 2 is formed on the substrate 1. Examples of the substrate that can be used in the present invention include a glass substrate, a quartz substrate, and a silicon substrate.
【０００９】陰極に使用できる材料としては、仕事関数
が４ｅＶより大きな材料であれば特に限定されない。具
体的には、Ａｌ、Ａｕ、Ａｇ、Ｆｅ、Ｎｉ及びＣｕ等が
挙げられ、特にＡｌが好ましい。これら金属は、従来陰
極に使用されていたＬｉ、Ｍｇ等の金属と比較して化学
的に安定であるため、酸化等による経時変化を抑えるこ
とができる。なお、仕事関数は、電子の注入効率及び駆
動電圧の抑制の観点からは小さい方が好ましく、化学的
安定性の観点からは大きい方が好ましい。従って、好ま
しい仕事関数の範囲は、４．１〜５．２ｅＶである。ま
た、陰極の厚さは、約０．１μｍが好ましい。陰極の形
成方法は、特に限定されず、公知の方法をいずれも使用
することができ、例えば、真空蒸着法、スパッタ法及び
電子ビーム蒸着法等が挙げられる。ここで、シリコン基
板を使用した場合は、該シリコン基板の表面層に、リ
ン、砒素等のｎ型不純物、ホウ素等のｐ型不純物を拡散
させた不純物層を陰極として使用してもよい。The material that can be used for the cathode is not particularly limited as long as it has a work function greater than 4 eV. Specifically, Al, Au, Ag, Fe, Ni, Cu and the like can be mentioned, and Al is particularly preferable. These metals are chemically more stable than metals such as Li and Mg which have been conventionally used for the cathode, so that a change with time due to oxidation or the like can be suppressed. The work function is preferably small from the viewpoint of electron injection efficiency and the suppression of driving voltage, and is preferably large from the viewpoint of chemical stability. Therefore, a preferable range of the work function is 4.1 to 5.2 eV. The thickness of the cathode is preferably about 0.1 μm. The method for forming the cathode is not particularly limited, and any known method can be used, and examples thereof include a vacuum evaporation method, a sputtering method, and an electron beam evaporation method. Here, when a silicon substrate is used, an impurity layer in which an n-type impurity such as phosphorus or arsenic or a p-type impurity such as boron is diffused in a surface layer of the silicon substrate may be used as a cathode.
【００１０】次に、陰極２上には絶縁膜３が形成され
る。絶縁膜に使用できる材料としては、上記陰極の酸化
物を好適に使用できる。具体的には、Ａｌ2 Ｏ3 、Ａｕ
2 Ｏ、Ａｇ2 Ｏ、Ｆｅ2 Ｏ3 、ＮｉＯ、ＣｕＯ等が挙げ
られる。また、絶縁膜の厚さは、０．００５〜０．０５
μｍが好ましい。絶縁膜の形成方法は、特に限定されな
い。例えば、上記陰極を酸化することにより得ることが
できる。また、絶縁膜が陰極とは異なる金属の酸化物か
らなる場合は、陰極上に所望の金属を積層した後に酸化
する方法や金属の水酸化物等を加熱分解する方法により
形成することができる。酸化は、陽極酸化法により行え
ば、緻密で絶縁耐圧の高い絶縁膜を得ることができるの
で好ましい。ここで、シリコン基板の表面層の不純物層
を陰極として使用した場合は、シリコン基板を熱酸化す
ることによりＳｉＯ2 からなる絶縁膜を簡便に得ること
ができる。Next, an insulating film 3 is formed on the cathode 2. As a material that can be used for the insulating film, the above-described oxide of the cathode can be suitably used. Specifically, Al 2 O 3 , Au
Examples include 2 O, Ag 2 O, Fe 2 O 3 , NiO, and CuO. The thickness of the insulating film is 0.005 to 0.05.
μm is preferred. The method for forming the insulating film is not particularly limited. For example, it can be obtained by oxidizing the cathode. In the case where the insulating film is made of an oxide of a metal different from that of the cathode, the insulating film can be formed by laminating a desired metal on the cathode and then oxidizing the same, or a method of thermally decomposing a metal hydroxide or the like. Oxidation is preferably performed by an anodic oxidation method because a dense insulating film with high withstand voltage can be obtained. Here, when the impurity layer of the surface layer of the silicon substrate is used as a cathode, an insulating film made of SiO 2 can be easily obtained by thermally oxidizing the silicon substrate.
【００１１】次いで、絶縁膜３上には有機薄膜４が形成
される。有機薄膜４は、例えば、電子輸送層／発光層／
ホール輸送層、発光層４ａ／ホール輸送層４ｂ等の積層
体であることが好ましい。電子輸送層に使用できる材料
としては、ガラス転移点が高く、結晶化を起こしにくい
化合物が好ましく、一般に電子写真感光体材料の分野に
おいて電子輸送性化合物として使用されている化合物が
挙げられる。具体的には、オキサジアゾリル誘導体等が
挙げられ、より具体的には、２−（４−ビフェニリル）
−５−（４−ターシャリーブチルフェニル）−１，３，
４−オキサジアゾール等が挙げられる。Next, an organic thin film 4 is formed on the insulating film 3. The organic thin film 4 includes, for example, an electron transport layer / a light emitting layer /
It is preferable to be a laminate of a hole transport layer, a light emitting layer 4a / a hole transport layer 4b, and the like. As a material that can be used for the electron transporting layer, a compound having a high glass transition point and hardly causing crystallization is preferable, and examples thereof include compounds that are generally used as an electron transporting compound in the field of electrophotographic photoreceptor materials. Specifically, oxadiazolyl derivatives and the like can be mentioned, and more specifically, 2- (4-biphenylyl)
-5- (4-tert-butylphenyl) -1,3,
4-oxadiazole and the like.
【００１２】発光層に使用できる材料としては、具体的
には、キノリールアルミニウム錯体（Ａｌｑ３）、キノ
リールベリリウム錯体、テトラフェニルブタジエン誘導
体等が挙げられる。ホール輸送層に使用できる材料とし
ては、具体的には、ジアミン誘導体等が挙げられる。よ
り具体的には、Ｎ，Ｎ−ビス（３−メチルフェニル）−
（１，１’−ビフェニル）−４，４’−ジアミン（ＴＰ
Ｄ）が挙げられる。Specific examples of the material that can be used for the light emitting layer include a quinolyl aluminum complex (Alq3), a quinolyl beryllium complex, and a tetraphenylbutadiene derivative. Specific examples of a material that can be used for the hole transport layer include a diamine derivative. More specifically, N, N-bis (3-methylphenyl)-
(1,1′-biphenyl) -4,4′-diamine (TP
D).
【００１３】なお、緑色の発光を所望する場合は、発光
層にＡｌｑ３、ホール輸送層にＴＰＤを使用することが
好ましい。電子輸送層、発光層及びホール輸送層は、そ
れぞれ０．０１〜０．１μｍ、０．０１〜０．１μｍ及
び０．０５〜０．１μｍの厚さを有することが好まし
い。また、これら有機薄膜の形成方法としては、特に限
定されないが、例えば真空蒸着法が挙げられる。When green light emission is desired, it is preferable to use Alq3 for the light emitting layer and TPD for the hole transport layer. The electron transport layer, the light emitting layer, and the hole transport layer preferably have a thickness of 0.01 to 0.1 μm, 0.01 to 0.1 μm, and 0.05 to 0.1 μm, respectively. The method for forming these organic thin films is not particularly limited, but includes, for example, a vacuum deposition method.
【００１４】この後、有機薄膜４上には陽極５が形成さ
れる。陽極に使用できる材料としては、一般に電子写真
感光体材料の分野において、陽極として使用されている
材料であれば特に限定されない。例えば、ＩＴＯ、Ｓｉ
Ｏ2 等の金属酸化物、Ａｕ、Ｎｉ等の金属が挙げられ
る。ここで、Ａｕ、Ｎｉ等の仕事関数の大きな金属を使
用すれば、ホール輸送層のＨＯＭＯ準位との障壁高さを
低くでき、それによりホール注入効率を向上させること
ができるので好ましい。なお、このような金属を使用す
る場合は、例えば図２に示すように、陽極５又は陰極２
の一方の面積を小さくして、面積の小さい方の電極側か
ら光を取り出すことが好ましい。この場合において、大
きい方の電極の面積と小さい方の電極の面積の比は、
１：０．１〜０．５であることが好ましい。なお、ＩＴ
Ｏのような透明材料以外の材料を電極として使用した場
合は、電極の厚さを薄くすることにより半透明膜として
光を取り出すことも可能である。また、ＩＴＯの成膜時
の基板の加熱温度は２００℃以下が好ましく、１００℃
以下がより好ましい。Thereafter, an anode 5 is formed on the organic thin film 4. The material that can be used for the anode is not particularly limited as long as it is generally used as an anode in the field of electrophotographic photoreceptor materials. For example, ITO, Si
Examples include metal oxides such as O 2 and metals such as Au and Ni. Here, it is preferable to use a metal having a large work function, such as Au or Ni, because the height of the barrier between the hole transport layer and the HOMO level can be reduced, thereby improving the hole injection efficiency. When such a metal is used, for example, as shown in FIG.
It is preferable to reduce the area of one of the electrodes and extract light from the electrode having the smaller area. In this case, the ratio of the area of the larger electrode to the area of the smaller electrode is
1: preferably 0.1 to 0.5. In addition, IT
When a material other than a transparent material such as O is used for the electrode, light can be extracted as a translucent film by reducing the thickness of the electrode. The heating temperature of the substrate at the time of ITO film formation is preferably 200 ° C. or less,
The following is more preferred.
【００１５】なお、上記では、基板、陰極、絶縁膜、有
機薄膜及び陽極の順で形成した有機発光素子について説
明したが、これに限定されず、基板、陰極、有機薄膜、
絶縁膜及び陽極の順で形成してもよい。但し、上記図１
の構成で有機発光素子を形成した場合、絶縁膜の形成を
有機薄膜の形成前に行うことができるので、有機薄膜は
酸化雰囲気中に晒されず、有機薄膜へのダメージを防ぐ
ことができる。In the above description, the organic light-emitting element formed in the order of the substrate, the cathode, the insulating film, the organic thin film, and the anode has been described.
The insulating film and the anode may be formed in this order. However, FIG.
When the organic light-emitting element is formed by the configuration described above, the formation of the insulating film can be performed before the formation of the organic thin film, so that the organic thin film is not exposed to an oxidizing atmosphere, and damage to the organic thin film can be prevented.
【００１６】次に、本発明の有機発光素子の作用につい
て説明する。なお、説明のために上記図１の積層順の有
機発光素子を使用している。キャリア注入型有機発光素
子では、図４に示すように、陰極の仕事関数と陰極に接
する有機薄膜のＬＵＭＯ準位の差がエネルギー障壁の高
さとなる。図４から判るように、従来の仕事関数の低い
陰極を使用した場合、エネルギー障壁が高くなり、陰極
からの電子注入は妨げられている。Next, the operation of the organic light emitting device of the present invention will be described. Note that, for the sake of explanation, the organic light emitting elements in the stacking order shown in FIG. 1 are used. In the carrier injection type organic light-emitting device, as shown in FIG. 4, the difference between the work function of the cathode and the LUMO level of the organic thin film in contact with the cathode becomes the height of the energy barrier. As can be seen from FIG. 4, when a conventional cathode having a low work function is used, the energy barrier increases, and electron injection from the cathode is hindered.
【００１７】これに対して、本発明では、図３に示すよ
うに、バイアス電圧を印加する時に、絶縁膜にかかる電
界強度が大きくなれば、エネルギー障壁が低くなる。つ
まりエネルギー障壁の高さを、絶縁膜の厚さとバイアス
電圧とで制御することが可能となる。従って、仕事関数
の大きな化学的に安定な金属を陰極の材料として使用し
ても、両者を制御することでエネルギー障壁を低く制御
することができるので、絶縁膜をトンネリングした電子
の有機薄膜への注入を容易にすることが可能となる。On the other hand, in the present invention, as shown in FIG. 3, when the electric field intensity applied to the insulating film increases when the bias voltage is applied, the energy barrier decreases. That is, the height of the energy barrier can be controlled by the thickness of the insulating film and the bias voltage. Therefore, even if a chemically stable metal having a large work function is used as the material of the cathode, the energy barrier can be controlled to be low by controlling both of them. Injection can be facilitated.
【００１８】これに対して、陽極から有機薄膜へ注入さ
れたホールは、電子よりホールのトンネリングの確率が
低いことから、絶縁膜によりブロックされることとな
る。よって、ホールの閉じ込め効率が向上し、発光効率
を上げることができる。On the other hand, holes injected from the anode into the organic thin film are blocked by the insulating film because holes have a lower probability of tunneling than electrons. Therefore, the hole confinement efficiency is improved, and the light emission efficiency can be improved.
【００１９】[0019]
【発明の効果】本発明の有機発光素子によれば、絶縁膜
を介して陰極からの電子注入効率を向上させることがで
きるので、発光効率を上げることができる。更に、仕事
関数が大きな化学的に安定な金属を陰極の材料として使
用できるので、陰極が酸化されることを防ぐことができ
る。従って、酸化による素子特性の劣化が抑制されるの
で、寿命が延び、信頼性も向上させることができる。According to the organic light emitting device of the present invention, the efficiency of injecting electrons from the cathode through the insulating film can be improved, so that the light emitting efficiency can be improved. Further, since a chemically stable metal having a large work function can be used as a material for the cathode, it is possible to prevent the cathode from being oxidized. Therefore, deterioration of device characteristics due to oxidation is suppressed, so that the life can be prolonged and the reliability can be improved.
【００２０】更に、本発明の有機発光素子の製造方法に
よれば、基板上に陰極から積層するので、絶縁膜形成時
の雰囲気下に有機薄膜が晒されることがなく、よって有
機薄膜の劣化を防ぐことができる。Further, according to the method for manufacturing an organic light emitting device of the present invention, since the organic thin film is laminated from the cathode on the substrate, the organic thin film is not exposed to the atmosphere during the formation of the insulating film. Can be prevented.
【図１】本発明の有機発光素子の概略断面図である。FIG. 1 is a schematic sectional view of an organic light emitting device of the present invention.
【図２】本発明の有機発光素子の陰極と陽極の構成を示
す概略平面図である。FIG. 2 is a schematic plan view showing a configuration of a cathode and an anode of the organic light emitting device of the present invention.
【図３】本発明の有機発光素子へのバイアス電圧の印加
時の概略エネルギー図である。FIG. 3 is a schematic energy diagram when a bias voltage is applied to the organic light emitting device of the present invention.
【図４】従来の有機発光素子へのバイアス電圧の無印加
時の概略エネルギー図である。FIG. 4 is a schematic energy diagram when a bias voltage is not applied to a conventional organic light emitting device.
１ 基板 ２ 陰極 ３ 絶縁膜 ４ 有機薄膜 ４ａ 発光層 ４ｂ ホール輸送層 ５ 陽極 Reference Signs List 1 substrate 2 cathode 3 insulating film 4 organic thin film 4a light emitting layer 4b hole transport layer 5 anode
Claims (4)
大きな材料からなる陰極、絶縁膜、有機薄膜及び陽極に
より構成され、かつキャリア注入型であることを特徴と
する有機発光素子。1. An organic light-emitting device comprising at least a substrate, a cathode, an insulating film, an organic thin film and an anode made of a material having a work function larger than 4 eV, and being of a carrier injection type.
より形成される酸化物である請求項１の有機発光素子。2. The organic light emitting device according to claim 1, wherein the insulating film is an oxide formed by oxidizing a surface of the cathode.
の順で積層された請求項１又は２の有機発光素子。3. The organic light-emitting device according to claim 1, wherein a substrate, a cathode, an insulating film, an organic thin film, and an anode are laminated in this order.
材料からなる陰極、絶縁膜、有機薄膜及び陽極をこの順
で形成することを特徴とするキャリア注入型の有機発光
素子の製造方法。4. A method for manufacturing a carrier-injection type organic light-emitting device, comprising: forming a cathode, an insulating film, an organic thin film, and an anode made of a material having a work function larger than 4 eV on a substrate in this order.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9151001A JPH10340787A (en) | 1997-06-09 | 1997-06-09 | Organic electroluminescent element and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9151001A JPH10340787A (en) | 1997-06-09 | 1997-06-09 | Organic electroluminescent element and its manufacture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10340787A true JPH10340787A (en) | 1998-12-22 |
Family
ID=15509126
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9151001A Pending JPH10340787A (en) | 1997-06-09 | 1997-06-09 | Organic electroluminescent element and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10340787A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000005928A1 (en) * | 1998-07-22 | 2000-02-03 | Tdk Corporation | Organic el device |
| JP2000040592A (en) * | 1998-07-21 | 2000-02-08 | Casio Comput Co Ltd | Electroluminescence element |
| WO2000010366A1 (en) * | 1998-08-13 | 2000-02-24 | Tdk Corporation | Organic el device |
| WO2000032014A1 (en) * | 1998-11-25 | 2000-06-02 | Tdk Corporation | Organic el device |
| WO2000056122A1 (en) * | 1999-03-16 | 2000-09-21 | Tdk Corporation | Organic el device |
| WO2000060906A1 (en) * | 1999-04-05 | 2000-10-12 | Tdk Corporation | Organic el device |
| JP2001093671A (en) * | 1999-09-22 | 2001-04-06 | Korea Electronics Telecommun | Organic electric field light-emitting element with double- insulating layer |
| US6369507B1 (en) | 1999-06-07 | 2002-04-09 | Tdk Corporation | Organic EL display apparatus with a switching device |
| WO2010134237A1 (en) * | 2009-05-22 | 2010-11-25 | シャープ株式会社 | Organic el display device and method for manufacturing same |
| JP2013165068A (en) * | 2013-04-15 | 2013-08-22 | Sony Corp | Top emission light-emitting element and manufacturing method of the same |
-
1997
- 1997-06-09 JP JP9151001A patent/JPH10340787A/en active Pending
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000040592A (en) * | 1998-07-21 | 2000-02-08 | Casio Comput Co Ltd | Electroluminescence element |
| WO2000005928A1 (en) * | 1998-07-22 | 2000-02-03 | Tdk Corporation | Organic el device |
| WO2000010366A1 (en) * | 1998-08-13 | 2000-02-24 | Tdk Corporation | Organic el device |
| WO2000032014A1 (en) * | 1998-11-25 | 2000-06-02 | Tdk Corporation | Organic el device |
| US6404126B1 (en) | 1998-11-25 | 2002-06-11 | Tdk Corporation | Organic electroluminescent device having a conjugated polymer and an inorganic insulative electron injecting and transporting layer |
| WO2000056122A1 (en) * | 1999-03-16 | 2000-09-21 | Tdk Corporation | Organic el device |
| US6262433B1 (en) | 1999-03-16 | 2001-07-17 | Tdk Corporation | Organic electroluminescent device |
| WO2000060906A1 (en) * | 1999-04-05 | 2000-10-12 | Tdk Corporation | Organic el device |
| US6252246B1 (en) | 1999-04-05 | 2001-06-26 | Tdk Corporation | Organic electroluminescent device |
| US6369507B1 (en) | 1999-06-07 | 2002-04-09 | Tdk Corporation | Organic EL display apparatus with a switching device |
| JP2001093671A (en) * | 1999-09-22 | 2001-04-06 | Korea Electronics Telecommun | Organic electric field light-emitting element with double- insulating layer |
| WO2010134237A1 (en) * | 2009-05-22 | 2010-11-25 | シャープ株式会社 | Organic el display device and method for manufacturing same |
| US8822983B2 (en) | 2009-05-22 | 2014-09-02 | Sharp Kabushiki Kaisha | Organic electroluminescent display device and manufacturing method thereof |
| JP2013165068A (en) * | 2013-04-15 | 2013-08-22 | Sony Corp | Top emission light-emitting element and manufacturing method of the same |
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