[go: up one dir, main page]

WO2000016361A1 - Dispositif electroluminescent organique (oled) emettant par le haut comportant des composes metalliques refractaires comme cathode inferieure - Google Patents

Dispositif electroluminescent organique (oled) emettant par le haut comportant des composes metalliques refractaires comme cathode inferieure Download PDF

Info

Publication number
WO2000016361A1
WO2000016361A1 PCT/US1999/020650 US9920650W WO0016361A1 WO 2000016361 A1 WO2000016361 A1 WO 2000016361A1 US 9920650 W US9920650 W US 9920650W WO 0016361 A1 WO0016361 A1 WO 0016361A1
Authority
WO
WIPO (PCT)
Prior art keywords
oled
work function
refractory metal
substrate
low work
Prior art date
Application number
PCT/US1999/020650
Other languages
English (en)
Inventor
Karl Pichler
Original Assignee
Fed Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fed Corporation filed Critical Fed Corporation
Priority to EP99969175A priority Critical patent/EP1029336A1/fr
Publication of WO2000016361A1 publication Critical patent/WO2000016361A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/805—Electrodes
    • H10K59/8052—Cathodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/302—Details of OLEDs of OLED structures
    • H10K2102/3023—Direction of light emission
    • H10K2102/3026—Top emission

Definitions

  • the present invention relates to an Organic Light Emitting Device ("OLED”) video display structure for a color video display or high brightness monochrome display and methods of making such. More specifically, the present invention relates to a top emitting OLED with a bottom cathode.
  • OLED Organic Light Emitting Device
  • OLEDs work on certain general principles.
  • An OLED is typically a laminate formed on a substrate such as soda-lime glass or silicon.
  • a light-emitting layer of a luminescent organic solid, as well as adjacent semiconductor layers, are sandwiched between a cathode and an anode.
  • the semiconductor layers may be hole-injecting or electron-injecting layers.
  • the light-emitting layer may be selected from any of a multitude of fluorescent organic solids.
  • the light-emitting layer may consist of multiple sublayers or a single blended layer.
  • the positive and negative charges meet in the layer(s) of organic material, they produce photons.
  • the wave length — and consequently the color ⁇ of the photons depends on the material properties of the organic material in which the photons are generated.
  • the color of light emitted from the OLED can be controlled by the selection of the organic material, or by the selection of dopants, or by other techniques known in the art. Different colored light may be generated by mixing the emitted light from different OLEDs. For example, white light is produced by mixing blue, red, and green light simultaneously.
  • Either the OLED anode or the cathode (or both) should be transparent in order to allow the emitted light to pass through to the viewer.
  • the cathode may be constructed of a low work function material and the holes may be injected from the anode, a high work function material, into the organic material via a hole transport layer.
  • OLEDs operate with a DC bias in the range of 2 to 30 volts.
  • the OLED brightness may be controlled by adjusting the voltage or current supplied to the anode and cathode.
  • the relative amount of light generated is commonly referred to as the "gray level.”
  • OLEDs may work better when operated in a current mode.
  • the light output may be more stable for constant current drive than for a constant voltage drive. This is in contrast to many other display technologies, which are normally operated in a voltage mode.
  • an active matrix display using OLED technology requires a specific pixel architecture to provide for a current mode of operation.
  • a matrix-addressed OLED device numerous individual OLEDs may be formed on a single substrate and arranged in groups in a grid pattern. Several OLED groups forming a column of the grid may share a common cathode, or cathode line. Several OLED groups forming a row of the grid may share a common anode, or anode line. The individual OLEDs in a given group emit light when their cathode line and anode line are activated at the same time. A group of OLEDs within the matrix may form one pixel in a display, with each OLED usually serving as one subpixel or pixel cell.
  • OLEDs have a number of beneficial characteristics. These include: a low activation voltage (about 5 volts); fast response when formed with a thin light-emitting layer; high brightness in proportion to the injected electric current; high visibility due to self-emission; superior impact resistance; and ease of handling of the solid state devices in which they are used.
  • OLEDs have practical application in television, graphic display systems, and digital printing. Although substantial progress has been made in the development of OLEDs to date, additional challenges remain. For example, OLEDs continue to face a general series of problems associated with their long-term stability. In particular, there is a need to provide a stable low work function cathode that is both a good electron injector for OLEDs and compatible with standard semiconductor processing. It would be particularly beneficial to provide an OLED cathode structure that is stable in an air ambient, so that semiconductor processing methods that are carried out in air may be utilized. Low work function cathodes currently in use with OLEDs have not demonstrated the required stability.
  • the present invention meets the needs set forth above and provides other benefits as well.
  • OLED comprising: a substrate; a low work function refractory metal layer overlying said substrate; a stack of one or more layers of light emitting organic material overlying said low work function refractory metal layer; and an anode conductor layer overlying said organic material.
  • Applicant has further developed an OLED comprising: a substrate; a c a t h o d e conductor layer overlying said substrate; a low work function refractory metal layer overlying said substrate; a stack of one or more layers of light emitting organic material overlying said low work function refractory layer; and an anode conductor layer overlying said organic material.
  • Applicant has still further developed an OLED comprising: a substrate; a cathode conductor layer overlying said substrate; a low work function refractory metal layer overlying said substrate; an insulator layer overlying said low work function refractory metal layer; a stack of one or more layers of light emitting organic material overlying said insulator layer; and an anode conductor layer overlying said organic material.
  • Applicant has also developed a method of making an OLED comprising the steps of: providing a substrate; forming a low work function refractory metal layer overlying said substrate; forming a stack of one or more organic materials overlying said low work function refractory metal layer; and forming an anode layer overlying said organic materials.
  • Applicant has also developed a method of making an OLED comprising the steps of: providing a substrate; forming a cathode conductor layer overlying said substrate; forming a low work function refractory metal layer overlying said cathode conductor layer; forming a stack of one or more organic materials overlying said low work function refractory metal layer; and forming an anode layer overlying said organic materials.
  • Applicant has also developed a method of making an OLED comprising the steps of: providing a substrate; forming a cathode conductor layer overlying said substrate; forming a low work function refractory metal layer overlying said cathode conductor layer; forming an insulator layer overlying said low work function refractory metal layer; forming a stack of one or more organic materials overlying said insulator layer; and forming an anode layer overlying said organic materials.
  • Applicant has also developed a method of making a substrate and cathode structure adapted to be handled in an air ambient and for use in a top emitting OLED having a top anode, the method comprising the steps of: providing a planar substrate material selected from the group consisting of silicon and glass; forming a cathode conductor layer overlying said substrate; and forming a low work function refractory metal layer overlying said cathode conductor layer.
  • Applicant has also developed a method of making a substrate and cathode structure adapted to be handled in an air ambient and for use in a top emitting OLED having a top anode, the method comprising the steps of: providing a planar substrate material selected from the group consisting of silicon and glass; and forming a low work function refractory metal layer overlying said substrate.
  • Fig. 1 is a cross-section in elevation of an OLED according to a first embodiment of the present invention.
  • Fig. 2 is a cross-section in elevation of an OLED according to a second embodiment of the present invention.
  • Fig. 3 is a cross-section in elevation of an OLED according to a third embodiment of the present invention.
  • Fig. 4 is a cross-section in elevation of an OLED according to a fourth embodiment of the present invention.
  • the first embodiment of the present invention is illustrated by the OLED 10 shown in Fig. 1.
  • the OLED 10 of the first embodiment of the present invention may include a substrate 300, a top anode layer
  • transparent or semi-transparent 100, a stack of one or more light emitting organic materials 200, a cathode conductor layer 400, and a low work function refractory metal layer 450.
  • Substrate 300 may be glass or part of a Si wafer which includes transistors and a plurality of pixels.
  • the cathode conductor layer 400 may be a reflective metal or alloy, such as Ag, Al, or Cr.
  • the reflective conductor layer 400 may enhance the brightness of the
  • OLED by reflecting light generated in the organic material 200 through the anode layer 100 towards a viewer.
  • the innovation provides a novel easy-to process (i.e., integration on Si-chip) and stable low work function bottom cathode.
  • a range of refactory metal compounds may be used (such as nitrides, borides and/or carbides of, for example, Ti, Zr, Hf, Nb, W, Mo, Cr, Ta or V) in the refractory metal layer 450.
  • the OLED 10 may include in particular a Si-chip substrate 300 with a built-in (pre-fabricated) pixelated TiN low work function refractory metal layer 450 as the OLED cathode.
  • the desired work function for the refractory metal layer 450 is below about 4 eV. It is preferable that the work function be below about 3.5 eV, and in some cases below about
  • the refractory metal compound selected be very stable in an air ambient.
  • a study of these refractory metal materials is provided in "Field Emission Cold Cathode Devices Based on Eutactic Systems," by V.G. Rivlin and D. Stewart, European Office of Aerospace Research and Development, London, England and Fulmar Research Institute, Stoke Poges, Slough SL2 4QD, England (prepared for U.S. Airforce Scientific Research, Boiling AFB, D.C. 20332 under contract/grant number: AFOSR-77-3292), incorporated by reference herein.
  • the preferred low work function material for the bottom cathode is TiN.
  • TiN has a work function typically in the range of 2.5 to 3 eV.
  • TiN may also provide a conductive plug in active matrix displays underlying an ITO (Indium Tin Oxide) layer to provide low resistance and highly stable (i.e. no oxidation) interconnects between the underlying electrodes and the ITO.
  • ITO Indium Tin Oxide
  • TiN is a good conductor with a resistivity of approximately 21.7 microohm-cm.
  • the construction of the TiN layer 450 may be integrated into the Si-chip manufacturing process.
  • the TiN layer 450 is environmentally stable allowing the Si substrate and the TiN layer to be handled in air, stored, shipped, cleaned, etc., without damage.
  • Other low work function cathodes cannot be integrated with the Si substrate and then handled because the materials are not typically stable.
  • the cathode conductor layer 400 may be eliminated if the low work function refractory metal layer 450 provides sufficient reflectivity to achieve the desired brightness for the OLED.
  • the cathode conductor layer 400 and the low work function refractory metal layer 450 are provided on the planar upper surface of the substrate 300 instead of as a plug as shown in Fig. 1.
  • an insulator layer of LiF, SiO, SiO 2 , or some other dielectric oxide, nitride, or oxi-nitride may be provided overlying the refractory metal layer 450 and below the organic material 200.
  • the OLED 10 may function better with a thin insulator layer 500 between the refractory metal layer 450 and the organics 200.
  • the thin insulator layer may be deposited in conjunction with the construction of the refractory metal layer 450 and the substrate 300.
  • top-emitting OLEDs generally have been forced to employ a bottom-anode and top-cathode structure primarily due to the lack of stability of the cathode when on the bottom (i.e., on the Si wafer).
  • This structure requires working with the top reactive cathode during the OLED deposition process.
  • the use of a top cathode structure complicates the manufacturing process and limits the choice of cathode materials.
  • Standard OLEDs may include bottom transparent anodes on glass and use top-opaque cathodes. TiN would be extremely difficult to use in this case because the deposition conditions for the TiN are likely to cause extensive damage to the underlying organic layer(s).
  • the present innovation allows for top emitting OLEDs with transparent top-anode structures.

Landscapes

  • Electroluminescent Light Sources (AREA)

Abstract

L'invention a trait à un dispositif (10) électroluminescent organique (OLED) émettant par le haut, qui comporte un substrat (300), une couche conductrice (400) de cathode possédant une couche de métal réfractaire (450) à faible potentiel de sortie, une couche de matière électroluminescente (200) organique, et une couche d'anode (100). La couche de métal réfractaire (450) à faible potentiel de sortie est sélectionnée de préférence dans le groupe constitué par un nitrure, un borure ou un carbure de Ti, Zr, Hf, Nb, W, Mo, Cr, Ta ou V.
PCT/US1999/020650 1998-09-11 1999-09-10 Dispositif electroluminescent organique (oled) emettant par le haut comportant des composes metalliques refractaires comme cathode inferieure WO2000016361A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP99969175A EP1029336A1 (fr) 1998-09-11 1999-09-10 Dispositif electroluminescent organique (oled) emettant par le haut comportant des composes metalliques refractaires comme cathode inferieure

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US9993998P 1998-09-11 1998-09-11
US60/099,939 1998-09-11

Publications (1)

Publication Number Publication Date
WO2000016361A1 true WO2000016361A1 (fr) 2000-03-23

Family

ID=22277323

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/020650 WO2000016361A1 (fr) 1998-09-11 1999-09-10 Dispositif electroluminescent organique (oled) emettant par le haut comportant des composes metalliques refractaires comme cathode inferieure

Country Status (2)

Country Link
EP (1) EP1029336A1 (fr)
WO (1) WO2000016361A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002021557A1 (fr) * 2000-09-06 2002-03-14 Osram Opto Semiconductors Gmbh Encapsulation pour dispositifs a diode electroluminescente organique
US6911666B2 (en) 2002-07-11 2005-06-28 Sharp Laboratories Of America, Inc. Flexible metal foil substrate display and method for forming same
SG111968A1 (en) * 2001-09-28 2005-06-29 Semiconductor Energy Lab Light emitting device and method of manufacturing the same
US7166007B2 (en) 1999-12-17 2007-01-23 Osram Opto Semiconductors Gmbh Encapsulation of electronic devices
US8021204B2 (en) 2002-04-23 2011-09-20 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US8044580B2 (en) 2002-04-26 2011-10-25 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method of the same
US8344360B2 (en) 1999-12-17 2013-01-01 Osram Opto Semiconductor Gmbh Organic electronic devices with an encapsulation
US8704243B2 (en) 2002-06-07 2014-04-22 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method thereof
US12398260B2 (en) 2020-06-30 2025-08-26 Basell Poliolefine Italia S.R.L. Polypropylene composition

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099091A (en) * 1976-07-28 1978-07-04 Matsushita Electric Industrial Co., Ltd. Electroluminescent panel including an electrically conductive layer between two electroluminescent layers
US5164799A (en) * 1990-04-26 1992-11-17 Fuji Xerox Co., Ltd. Thin-film electroluminescent device having a dual dielectric structure
JPH10125469A (ja) * 1996-10-24 1998-05-15 Tdk Corp 有機ｅｌ発光素子

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4099091A (en) * 1976-07-28 1978-07-04 Matsushita Electric Industrial Co., Ltd. Electroluminescent panel including an electrically conductive layer between two electroluminescent layers
US5164799A (en) * 1990-04-26 1992-11-17 Fuji Xerox Co., Ltd. Thin-film electroluminescent device having a dual dielectric structure
JPH10125469A (ja) * 1996-10-24 1998-05-15 Tdk Corp 有機ｅｌ発光素子
US5969474A (en) * 1996-10-24 1999-10-19 Tdk Corporation Organic light-emitting device with light transmissive anode and light transmissive cathode including zinc-doped indium oxide

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8344360B2 (en) 1999-12-17 2013-01-01 Osram Opto Semiconductor Gmbh Organic electronic devices with an encapsulation
US7166007B2 (en) 1999-12-17 2007-01-23 Osram Opto Semiconductors Gmbh Encapsulation of electronic devices
US7394153B2 (en) 1999-12-17 2008-07-01 Osram Opto Semiconductors Gmbh Encapsulation of electronic devices
US7419842B2 (en) 1999-12-17 2008-09-02 Osram Gmbh Encapsulation of electroluminescent devices with shaped spacers
US7432533B2 (en) 1999-12-17 2008-10-07 Osram Gmbh Encapsulation of electronic devices with shaped spacers
WO2002021557A1 (fr) * 2000-09-06 2002-03-14 Osram Opto Semiconductors Gmbh Encapsulation pour dispositifs a diode electroluminescente organique
US7255823B1 (en) 2000-09-06 2007-08-14 Institute Of Materials Research And Engineering Encapsulation for oled devices
SG111968A1 (en) * 2001-09-28 2005-06-29 Semiconductor Energy Lab Light emitting device and method of manufacturing the same
US7108574B2 (en) 2001-09-28 2006-09-19 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US7193359B2 (en) 2001-09-28 2007-03-20 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US8021204B2 (en) 2002-04-23 2011-09-20 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US8519619B2 (en) 2002-04-23 2013-08-27 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US9287330B2 (en) 2002-04-23 2016-03-15 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US9978811B2 (en) 2002-04-23 2018-05-22 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and method of manufacturing the same
US8044580B2 (en) 2002-04-26 2011-10-25 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method of the same
US8497628B2 (en) 2002-04-26 2013-07-30 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method of the same
US8803418B2 (en) 2002-04-26 2014-08-12 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method of the same
US9412804B2 (en) 2002-04-26 2016-08-09 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method of the same
US9853098B2 (en) 2002-04-26 2017-12-26 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method of the same
US8704243B2 (en) 2002-06-07 2014-04-22 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method thereof
US9166202B2 (en) 2002-06-07 2015-10-20 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method thereof
US6911666B2 (en) 2002-07-11 2005-06-28 Sharp Laboratories Of America, Inc. Flexible metal foil substrate display and method for forming same
US12398260B2 (en) 2020-06-30 2025-08-26 Basell Poliolefine Italia S.R.L. Polypropylene composition

Also Published As

Publication number Publication date
EP1029336A1 (fr) 2000-08-23

Similar Documents

Publication Publication Date Title
US6016033A (en) Electrode structure for high resolution organic light-emitting diode displays and method for making the same
CN100472795C (zh) 有机发光显示器装置及其制造方法
JP3884564B2 (ja) 有機ｅｌ発光素子およびそれを用いた発光装置
US6580214B2 (en) Color display apparatus having electroluminescence elements
JP3861400B2 (ja) 電界発光素子およびその製造方法
TWI500144B (zh) 有機發光顯示裝置及其製造方法
US6320322B1 (en) Light emitting appliance
Gu et al. High-efficiency, low-drive-voltage, semitransparent stacked organic light-emitting device
US20060181204A1 (en) Flexible organic light emitting devices
EP0987774A2 (fr) Electrode avec injection des trous améliorée
JP2002508108A (ja) 有機発光ダイオードを用いた発光ディスプレイ
US20060152150A1 (en) Electroluminescent display with improved light outcoupling
EP1018168A4 (fr) Dispositif electroluminescent organique a haute luminosite et a haut rendement
US20080164812A1 (en) Method for fabricating a system for displaying images
EP1029336A1 (fr) Dispositif electroluminescent organique (oled) emettant par le haut comportant des composes metalliques refractaires comme cathode inferieure
JP2001076882A (ja) 有機ｅｌ素子およびその製法ならびに表示装置
JP4213169B2 (ja) 有機ｅｌ発光素子およびそれを用いた発光装置
US6278417B1 (en) Method of driving a display device, and a display device
US20060103321A1 (en) Electroluminescent device with a transparent cathode
US7538489B2 (en) Full-color active matrix organic electroluminescent device, fabrication method thereof and electronic devices employing the same
KR101604495B1 (ko) 유기발광다이오드 표시장치 및 이를 제조하는 방법
JP2010277949A (ja) 有機ｅｌ表示装置及びその製造方法
JP2006344606A (ja) 有機ｅｌ発光素子およびそれを用いた発光装置
WO2000057446A1 (fr) Electrodes haute efficacite pour dispositifs organiques a diodes electroluminescentes
Burrows et al. Stacked organic light-emitting devices for full-color flat panel displays

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

WWE Wipo information: entry into national phase

Ref document number: 1999969175

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 09554066

Country of ref document: US

121 Ep: the epo has been informed by wipo that ep was designated in this application
WWP Wipo information: published in national office

Ref document number: 1999969175

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1999969175

Country of ref document: EP