Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/12—Organic material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/228—Gas flow assisted PVD deposition
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/24—Vacuum evaporation
  • C23C14/246—Replenishment of source material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S427/00—Coating processes
  • Y10S427/101—Liquid Source Chemical Depostion, i.e. LSCVD or Aerosol Chemical Vapor Deposition, i.e. ACVD

Definitions

• OLED organic light emitting diode
• the high thermal conductivity insures good temperature uniformity through the structure and the large thermal mass helps to maintain the temperature within a critically small range by reducing temperature fluctuations.
• These measures have the desired effect on steady-state vaporization rate stability but have a detrimental effect at start-up. It is common that these devices must operate for many hours at start-up before steady state thermal equilibrium and hence a steady vaporization rate is achieved.
• a further limitation of prior art sources is that the geometry of the vapor manifold changes as the organic material charge is consumed. This change requires that the heater temperature change to maintain a constant vaporization rate and it is observed that the plume shape of the vapor exiting the orifices changes as a function of the organic material thickness and distribution in the source.
• a method for vaporizing organic materials onto a surface, to form a film comprising: (a) providing a quantity of organic material in a fluidized powdered form; (b) metering the powdered organic material and directing a stream of such fluidized powder onto a first member; (c) heating the first member so that as the stream of fluidized powder is vaporized; (d) collecting the vaporized organic material in a manifold; and (e) providing a second member formed with at least one aperture in communication with the manifold that permits the vaporized organic material to be directed onto the surface to form a film.
• the device overcomes the heating and volume limitations of prior art devices in that only a small portion of organic material as a fluidized powder or an aerosol suspended in an inert carrier gas is heated to the desired rate-dependant vaporization temperature at a rapid rate, so that the organic material changes very rapidly from the solid to the vapor state and is said to undergo flash vaporization. It is therefore a feature of the present invention to maintain a steady vaporization rate and a steady heater temperature.
• the device thus allows extended operation of the source with substantially reduced risk of degrading even very temperature- sensitive organic materials. Flash vaporization additionally permits materials having different vaporization rates and degradation temperature thresholds to be co-vaporized without the need for multiple, angled sources as in the prior art.
• FIG. 1 is a cross-sectional view of one embodiment of a device according to the present invention including a means for metering powdered organic material and directing a stream of fluidized powder into a heating region;
• FIG. 2 shows a graphical representation of vapor pressure vs. temperature for two organic materials;
• FIG. 3 is a cross-sectional view of a device according to the present invention including a deposition chamber enclosing a substrate; and
• FIG. 4 is a cross-sectional view of an OLED device structure that can be prepared with the present invention.
• DETAILED DESCRIPTION OF THE INVENTION Turning now to FIG. 1, there is shown a cross sectional view of one embodiment of a device of this disclosure.
• Vaporization apparatus 5 is a device for vaporizing organic materials onto a substrate surface to form a film and includes a permeable first member 40, a manifold 60, and a metering means, by which we mean a means for fluidizing powdered organic material or providing organic material in a fluidized powdered form, metering the powdered organic material and directing a stream of such fluidized powder onto permeable first member 40.
• Permeable first member 40 can be part of manifold 60.
• Manifold 60 also includes one or more apertures 90.
• Vaporization apparatus 5 also includes one or more shields 70.
• container 45 is a container for receiving a quantity of organic material in powdered form.
• Metering valve 55 in this embodiment includes a means for fluidizing the organic material and metering the fluidized powdered organic material at a controlled rate that varies linearly with vaporization rate.
• Organic material inlet 10 with nozzle 15 is a means for directing a stream of the fluidized powdered organic material onto permeable first member 40.
• Well-known means of fluidizing a powder include vibrational means, imparting a charge to the particles, and partially suspending the particles in a fluid medium.
• container 45 is a container for holding a charge of organic material suspended as an aerosol in an inert carrier gas.
• Metering valve 55 in this embodiment includes a means for metering an aerosol of fluidized powdered organic material at a controlled rate that varies linearly with vaporization rate.
• container 45 holds a solution of organic material dissolved in a supercritical solvent, such as supercritical CO 2 .
• Evaporation or rapid expansion of the solution of organic material in the supercritical solvent is a means for providing organic material in a fluidized powdered form.
• Metering valve 55 includes a means for metering the thus-generated fluidized powdered organic material at a controlled rate that varies linearly with vaporization rate.
• the organic material can include a single component, or can include two or more organic components, each one having a different vaporization temperature. The vaporization temperature can be determined by various means. For example, FIG.
• FIG. 2 shows a graphical representation of vapor pressure versus temperature for two organic materials commonly used in OLED devices.
• the vaporization rate is proportional to the vapor pressure, so for a desired vaporization rate, the data in FIG. 2 can be used to define the required heating temperature corresponding to the desired vaporization rate.
• Fluidized powdered organic material is metered at a controlled rate by metering valve 55.
• Organic material inlet 10 including nozzle 15 includes a means for directing the stream of fluidized powdered organic material onto permeable first member 40.
• Nozzle 15 can be a heated nozzle.
• the outer surface of nozzle 15 is preferentially maintained at a temperature above the condensation temperature of the vapor so as to avoid accumulating condensed organic material on its surface, which can clog the nozzle orifice.
• the interior of the nozzle should be maintained at a temperature below the vaporization or melting point of the powdered organic material to similarly avoid clogging, especially with materials that liquefy before vaporizing. This requirement suggests the use of a nozzle construction having separate elements for the interior and exterior surfaces.
• Permeable first member 40 is heated at a constant temperature and can take the form of open cell refractory foam. Various refractory metal and ceramic foams having an open cell structure of this type are available from e.g. ULTRAMET.
• Means for heating permeable first member 40 include induction or RF coupling, a radiant heating element in close proximity, or resistance heating means.
• Permeable first member 40 is controllably heated at a constant temperature sufficient to vaporize the organic material at the desired rate, which is a temperature above the vaporization temperature of the organic material, or each of the organic components thereof. Because a given organic component vaporizes at different rates over a continuum of temperatures, there is a logarithmic dependence of vaporization rate on temperature. In choosing a desired deposition rate, one also determines a necessary vaporization temperature of the organic material, which will be referred to as the desired rate-dependent vaporization temperature.
• the temperature of permeable first member 40 is chosen to be above the vaporization temperature of each of the components so that each of the organic material components simultaneously vaporizes.
• the vaporized organic material vapors rapidly pass through permeable first member 40 and can enter into a volume of heated gas manifold 60 or pass directly on to the target substrate.
• Their residence time at the desired vaporization temperature is very short and as a result, there is little or no thermal degradation.
• the residence time of organic material at elevated temperature that is, at the rate-dependent vaporization temperature, is orders of magnitude less than prior art devices and methods (seconds vs. hours or days in the prior art), which permits heating organic material to higher temperatures than in the prior art.
• the current device and method can achieve substantially higher vaporization rates, without causing appreciable degradation of organic material.
• the constant vaporization rate establishes and maintains a constant plume shape.
• the plume is herein defined as the vapor cloud exiting vaporization device 5.
• the organic material aerosol is shown impinging the lower surface of permeable first member 40, vaporizing, and the vapor passing through permeable first member 40 to enter the heated gas manifold 60.
• the invention can also be practiced where the aerosol impinges the manifold side of the permeable first member 40. In this case, the vapor is created directly in the heated gas manifold and does not pass through permeable first member 40.
• permeable first member 40 is preferably not porous through its entire thickness, but retains the high specific surface area characteristics of a porous media at least on the surface where the aerosol impinges.
• Manifold 60 is in communication with vaporized organic material that exits permeable first member 40. Thus, vaporized organic material is collected in manifold 60. A pressure develops as vaporization continues and streams of vapor exit the manifold 60 through the series of apertures 90 in second member 50.
• Second member 50 can be an integral part of manifold 60, as shown here, or can be a separate but attached unit.
• Apertures 90 are in communication with manifold 60 such that vaporized organic material collected by manifold 60 can be directed through apertures 90 onto a surface such as that of an OLED substrate.
• Manifold 60 and second member 50 can be heated at a constant temperature by heating means such as that described above for permeable first member 40.
• the conductance along the length of the manifold is designed to be roughly two orders of magnitude larger than the sum of the aperture conductances as described by Grace et al. in above-cited U.S. Patent Application Serial No. 10/352,558. This conductance ratio promotes good pressure uniformity within manifold 60 and thereby minimizes flow non-uniformities through apertures 90 distributed along the length of the source despite potential local non-uniformities in vaporization rate.
• One or more heat shields 70 are located adjacent the heated manifold 60 for the purpose of reducing the heat radiated to the facing target substrate. Heat shields 70 are thermally connected to base block 20 for the purpose of drawing heat away from the shields 70. Control passages 30 through this base block 20 allow the flow of a temperature control fluid, that is, a fluid adapted to either absorb heat from or deliver heat to base block 20 and thus provide a means of moderating the temperature of heat shields 70 by varying the temperature of the fluid in control passage 30.
• the fluid can be a gas or a liquid or a mixed phase.
• Vaporization apparatus 5 includes a means for pumping fluid through control passages 30. Such pumping means, not shown, are well known to those skilled in the art.
• heat shields 70 is designed to lie below the plane of the apertures for the purpose of minimizing vapor condensation on their relatively cool surfaces. Because only a small portion of organic material — that resident in permeable first member 40 — is heated to the rate-dependent vaporization temperature, while the bulk of the material is kept well below the vaporization temperature, it is possible to interrupt the vaporization by a means for interrupting heating in permeable first member 40, e.g. stopping the flow of fluidized powdered organic material through metering valve 55 and therefore through permeable first member 40. This can be done when a substrate surface is not being coated so as to conserve organic material and minimize contamination of any associated apparatus, such as the walls of a deposition chamber, which will be described below.
• vaporization apparatus 5 can be used in any orientation.
• vaporization apparatus 5 can be oriented 180° from what is shown in FIG. 1 so as to coat a substrate placed below it. This is an advantage not found in the heating boats of the prior art.
• vaporization apparatus 5 can be used as follows. A quantity of powdered organic material, which can include one or more components, is provided into container 45 of vaporization apparatus 5. Permeable first member 40 is heated to a temperature above the vaporization temperature of the organic material or each of the components thereof and is maintained at a constant temperature as organic material is consumed.
• Powdered organic material is fluidized and metered at a controlled rate by metering valve 55 to organic material inlet 10 and consequently to nozzle 15, which directs the stream of fluidized powder onto permeable first member 40.
• permeable first member 40 As the stream of fluidized powdered organic material passes through permeable first member 40, it is heated at a desired rate-dependent vaporization temperature and vaporizes.
• each component simultaneously vaporizes.
• the vaporized organic material is collected in manifold 60, whereupon it passes through apertures 90 in provided second member 50, which direct the vaporized organic material onto a substrate surface to form a film. If second member 50 is heated, it is heated at a constant temperature as the organic material is consumed.
• vaporization apparatus 5 can be used as follows.
• a supercritical CO 2 solution of organic material which can include one or more components, is provided into container 45 of vaporization apparatus 5.
• Permeable first member 40 is heated to a temperature above the vaporization temperature of the organic material or each of the components thereof. Evaporation of the supercritical CO solution provides organic material in a fluidized powdered form, which is metered at a controlled rate by metering valve 55 to organic material inlet 10 and consequently to nozzle 15, which directs the stream of fluidized powder onto permeable first member 40.
• the stream of fluidized powdered organic material passes through permeable first member 40, it is heated at a desired rate- dependent vaporization temperature and vaporizes.
• each component simultaneously vaporizes.
• Deposition chamber 80 is an enclosed apparatus that permits an OLED substrate 85 to be coated with a film of organic material transferred from vaporization apparatus 5.
• Deposition chamber 80 is held under controlled conditions, e.g. a pressure of 1 torr or less provided by vacuum source 100.
• Deposition chamber 80 includes load lock 75 which can be used to load uncoated OLED substrates 85, and unload coated OLED substrates.
• OLED substrate 85 can be moved by translational apparatus 95 to provide even coating of vaporized organic material 10 over the entire surface of OLED substrate 85.
• vaporization apparatus 5 is shown as partially enclosed by deposition chamber 80, it will be understood that other arrangements are possible, including arrangements wherein vaporization apparatus 5 is entirely enclosed by deposition chamber 80. In practice, an OLED substrate 85 is placed in deposition chamber
• FIG. 4 there is shown a cross-sectional view of a pixel of a light-emitting OLED device 110 that can be prepared in part according to the present invention.
• the OLED device 110 includes at a minimum a substrate 120, a cathode 190, an anode 130 spaced from cathode 190, and a light-emitting layer 150.
• the OLED device 110 can also include a hole-injecting layer 135, a hole-transporting layer 140, an electron-transporting layer 155, and an electron- injecting layer 160.
• Hole-injecting layer 135, hole-transporting layer 140, light- emitting layer 150, electron-transporting layer 155, and electron-injecting layer 160 include a series of organic layers 170 disposed between anode 130 and cathode 190.
• Organic layers 170 are the layers most desirably deposited by the device and method of this invention, and the components including these layers are the organic materials of the present method. These components will be described in more detail.
• Substrate 120 can be an organic solid, an inorganic solid, or a combination of organic and inorganic solids.
• Substrate 120 can be rigid or flexible and can be processed as separate individual pieces, such as sheets or wafers, or as a continuous roll. Typical substrate materials include glass, plastic, metal, ceramic, semiconductor, metal oxide, semiconductor oxide, semiconductor nitride, or combinations thereof. Substrate 120 can be a homogeneous mixture of materials, a composite of materials, or multiple layers of materials. Substrate 120 can be an OLED substrate, that is a substrate commonly used for preparing OLED devices, e.g. active-matrix low-temperature polysilicon or amorphous-silicon TFT substrate. The substrate 120 can either be light transmissive or opaque, depending on the intended direction of light emission. The light transmissive property is desirable for viewing the EL emission through the substrate 120.
• Transparent glass or plastic are commonly employed in such cases.
• the transmissive characteristic of the bottom support is immaterial, and therefore can be light transmissive, light absorbing or light reflective.
• Substrates for use in this case include, but are not limited to, glass, plastic, semiconductor materials, ceramics, and circuit board materials, or any others commonly used in the formation of OLED devices, which can be either passive-matrix devices or active-matrix devices.
• An electro.de is formed over substrate 120 and is most commonly configured as an anode 130. When EL emission is viewed through the substrate 120, anode 130 should be transparent or substantially transparent to the emission of interest.
• Common transparent anode materials useful in this invention are indium-tin oxide and tin oxide, but other metal oxides can work including, but not limited to, aluminum- or indium-doped zinc oxide, magnesium-indium oxide, and nickel-tungsten oxide.
• metal nitrides such as gallium nitride, metal selenides such as zinc selenide, and metal sulfides such as zinc sulfide, can be used as an anode material.
• the transmissive characteristics of the anode material are immaterial and any conductive material can be used, transparent, opaque or reflective.
• Example conductors for this application include, but are not limited to, gold, iridium, molybdenum, palladium, and platinum.
• the preferred anode materials, transmissive or otherwise, have a work function of 4.1 eV or greater. Desired anode materials can be deposited by any suitable means such as evaporation, sputtering, chemical vapor deposition, or electrochemical means. Anode materials can be patterned using well known photolithographic processes. While not always necessary, it is often useful that a hole-injecting layer 135 be formed over anode 130 in an organic light-emitting display. The hole-injecting material can serve to improve the film formation property of subsequent organic layers and to facilitate injection of holes into the hole- transporting layer 140.
• Suitable materials for use in hole-injecting layer 135 include, but are not limited to, porphyrinic compounds as described in U.S. Patent No. 4,720,432, plasma-deposited fluorocarbon polymers as described in U.S. Patent No. 6,208,075, and inorganic oxides including vanadium oxide (VOx), molybdenum oxide (MoOx), nickel oxide (NiOx), etc.
• Alternative hole-injecting materials reportedly useful in organic EL devices are described in EP 0 891 121 Al and EP 1 029 909 Al. While not always necessary, it is often useful that a hole- transporting layer 140 be formed and disposed over anode 130.
• Desired hole- transporting materials can be deposited by any suitable means such as evaporation, sputtering, chemical vapor deposition, electrochemical means, thermal transfer, or laser thermal transfer from a donor material, and can be deposited by the device and method described herein.
• Hole-transporting materials useful in hole- transporting layer 140 are well known to include compounds such as an aromatic tertiary amine, where the latter is understood to be a compound containing at least one trivalent nitrogen atom that is bonded only to carbon atoms, at least one of which is a member of an aromatic ring.
• the aromatic tertiary amine can be an arylamine, such as a monoarylamine, diarylamine, triarylamine, or a polymeric arylamine.
• Exemplary monomeric triarylamines are illustrated by Klupfel et al. in U.S. Patent No. 3,180,730.
• Other suitable triarylamines substituted with one or more vinyl radicals and/or including at least one active hydrogen-containing group are disclosed by Brantley et al. in U.S. Patent Nos. 3,567,450 and 3,658,520.
• a more preferred class of aromatic tertiary amines are those which include at least two aromatic tertiary amine moieties as described in U.S. Patent Nos. 4,720,432 and 5,061,569.
• Such compounds include those represented by structural Formula A.
• Qi and Q 2 are independently selected aromatic tertiary amine moieties; and G is a linking group such as an arylene, cycloalkylene, or alkylene group of a carbon to carbon bond.
• G is a linking group such as an arylene, cycloalkylene, or alkylene group of a carbon to carbon bond.
• at least one of Ql or Q2 contains a polycyclic fused ring structure, e.g., a naphthalene.
• G is an aryl group, it is conveniently a phenylene, biphenylene, or naphthalene moiety.
• a useful class of triarylamines satisfying structural Formula A and containing two triarylamine moieties is represented by structural Formula B.
• Ri and R 2 each independently represent a hydrogen atom, an aryl group, or an alkyl group or R ⁇ and R 2 together represent the atoms completing a cycloalkyl group; and R 3 and 4 each independently represent an aryl group, which is in turn substituted with a diaryl substituted amino group, as indicated by structural Formula C.
• R5 c wherein R 5 and R 6 are independently selected aryl groups.
• at least one of R 5 or R 6 contains a polycyclic fused ring structure, e.g., a naphthalene.
• Another class of aromatic tertiary amines is the tetraaryldiamines.
• Desirable tetraaryldiamines include two diarylamino groups, such as indicated by Formula C, linked through an arylene group.
• Useful tetraaryldiamines include those represented by Formula D. wherein: each Are is an independently selected arylene group, such as a phenylene or anthracene moiety; n is an integer of from 1 to 4; and Ar, R 7 , R 8 , and R 9 are independently selected aryl groups.
• at least one of Ar, R , R 8 , and R 9 is a polycyclic fused ring structure, e.g., a naphthalene.
• the various alkyl, alkylene, aryl, and arylene moieties of the foregoing structural Formulae A, B, C, D, can each in turn be substituted.
• Typical substituents include alkyl groups, alkoxy groups, aryl groups, aryloxy groups, and halogens such as fluoride, chloride, and bromide.
• the various alkyl and alkylene moieties typically contain from 1 to about 6 carbon atoms.
• the cycloalkyl moieties can contain from 3 to about 10 carbon atoms, but typically contain five, six, or seven carbon atoms ⁇ e.g., cyclopentyl, cyclohexyl, and cycloheptyl ring structures.
• the aryl and arylene moieties are usually phenyl and phenylene moieties.
• the hole-transporting layer in an OLED device can be formed of a single or a mixture of aromatic tertiary amine compounds. Specifically, one can employ a triarylamine, such as a triarylamine satisfying the Formula B, in combination with a tetraaryldiamine, such as indicated by Formula D. When a triarylamine is employed in combination with a tetraaryldiamine, the latter is positioned as a layer interposed between the triarylamine and the electron- injecting and transporting layer.
• the device and method described herein can be used to deposit single- or multi-component layers, and can be used to sequentially deposit multiple layers.
• Another class of useful hole-transporting materials includes polycyclic aromatic compounds as described in EP 1 009 041.
• polymeric hole-transporting materials can be used such as poly(N-vinylcarbazole) (PNK), polythiophenes, polypyrrole, polyaniline, and copolymers such as poly(3 ,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) also called PEDOT/PSS.
• Light-emitting layer 150 produces light in response to hole-electron recombination. Light-emitting layer 150 is commonly disposed over hole- transporting layer 140.
• Desired organic light-emitting materials can be deposited by any suitable means such as evaporation, sputtering, chemical vapor deposition, electrochemical means, or radiation thermal transfer from a donor material, and can be deposited by the device and method described herein.
• Useful organic light- emitting materials are well known.
• the light-emitting layers of the organic EL element include a luminescent or fluorescent material where electroluminescence is produced as a result of electron-hole pair recombination in this region.
• the light- emitting layers can include a single material, but more commonly include a host material doped with a guest compound or dopant where light emission comes primarily from the dopant.
• the dopant is selected to produce color light having a particular spectrum.
• the host materials in the light-emitting layers can be an electron-transporting material, as defined below, a hole-transporting material, as defined above, or another material that supports hole-electron recombination.
• the dopant is usually chosen from highly fluorescent dyes, but phosphorescent compounds, e.g., transition metal complexes as described in WO 98/55561, WO 00/18851 , WO 00/57676, and WO 00/70655 are also useful. Dopants are typically coated as 0.01 to 10 % by weight into the host material.
• the device and method described herein can be used to coat multi-component guest/host layers without the need for multiple vaporization sources. Host and emitting molecules known to be of use include, but are not limited to, those disclosed in U.S. Patent Nos. 4,768,292; 5,141,671 ;
• Metal complexes of 8-hydroxyquinoline and similar derivatives constitute one class of useful host materials capable of supporting electroluminescence, and are particularly suitable for light emission of wavelengths longer than 500 nm, e.g., green, yellow, orange, and red.
• M represents a metal
• n is an integer of from 1 to 3
• Z independently in each occurrence represents the atoms completing a nucleus having at least two fused aromatic rings.
• the metal can be a monovalent, divalent, or trivalent metal.
• the metal can, for example, be an alkali metal, such as lithium, sodium, or potassium; an alkaline earth metal, such as magnesium or calcium; or an earth metal, such as boron or aluminum.
• any monovalent, divalent, or trivalent metal known to be a useful chelating metal can be employed.
• Z completes a heterocyclic nucleus containing at least two fused aromatic rings, at least one of which is an azole or azine ring.
• the host material in light-emitting layer 150 can be an anthracene derivative having hydrocarbon or substituted hydrocarbon substituents at the 9 and 10 positions.
• derivatives of 9,10-di-(2-naphthyl)anthracene constitute one class of useful host materials capable of supporting electroluminescence, and are particularly suitable for light emission of wavelengths longer than 400 nm, e.g., blue, green, yellow, orange or red.
• Benzazole derivatives constitute another class of useful host materials capable of supporting electroluminescence, and are particularly suitable for light emission of wavelengths longer than 400 nm, e.g., blue, green, yellow, orange or red.
• An example of a useful benzazole is 2, 2', 2"-(l,3,5- phenylene)tris[ 1 -phenyl- 1 H-benzimidazole] .
• Desirable fluorescent dopants include perylene or derivatives of perylene, derivatives of anthracene, tetracene, xanthene, rubrene, coumarin, rhodamine, quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrilium and thiapyrilium compounds, derivatives of distyrylbenzene or distyrylbiphenyl, bis(azinyl)methane boron complex compounds, and carbostyryl compounds.
• Other organic emissive materials can be polymeric substances, e.g.
• OLED device 110 includes an electron-transporting layer 155 disposed over light-emitting layer 150.
• Desired electron-transporting materials can be deposited by any suitable means such as evaporation, sputtering, chemical vapor deposition, electrochemical means, thermal transfer, or laser thermal transfer from a donor material, and can be deposited by the device and method described herein.
• Preferred electron- transporting materials for use in electron-transporting layer 155 are metal chelated oxinoid compounds, including chelates of oxine itself (also commonly referred to as 8-quinolinol or 8-hydroxyquinoline). Such compounds help to inject and transport electrons and exhibit both high levels of performance and are readily fabricated in the form of thin films.
• Exemplary of contemplated oxinoid compounds are those satisfying structural Formula E, previously described.
• Other electron-transporting materials include various butadiene derivatives as disclosed in U.S. Patent No. 4,356,429 and various heterocyclic optical brighteners as described in U.S. Patent No. 4,539,507. Benzazoles satisfying structural Formula G are also useful electron-transporting materials.
• electron-transporting materials can be polymeric substances, e.g. polyphenylenevinylene derivatives, poly-para-phenylene derivatives, polyfluorene derivatives, polythiophenes, polyacetylenes, and other conductive polymeric organic materials such as those listed in Han ⁇ book ofCon ⁇ uctive Molecules an ⁇ Polymers, Vols. 1-4, H.S. Nalwa, ed., John Wiley and Sons, Chichester (1997).
• An electron-injecting layer 160 can also be present between the cathode 190 and the electron-transporting layer 155.
• Examples of electron- injecting materials include alkaline or alkaline earth metals, alkali halide salts, such as LiF mentioned above, or alkaline or alkaline earth metal doped organic layers.
• Cathode 190 is formed over the electron-transporting layer 155 or over light-emitting layer 150 if an electron-transporting layer 155 is not used.
• the cathode material can include nearly any conductive material. Desirable materials have good film-forming properties to ensure good contact with the underlying organic layer, promote electron injection at low voltage, and have good stability.
• Useful cathode materials often contain a low work function metal ( ⁇ 3.0 eV) or metal alloy.
• One preferred cathode material includes a Mg:Ag alloy wherein the percentage of silver is in the range of 1 to 20 %, as described in U.S. Patent No. 4,885,221.
• Another suitable class of cathode materials includes bilayers having a thin layer of a low work function metal or metal salt capped with a thicker layer of conductive metal.
• One such cathode includes a thin layer of LiF followed by a thicker layer of Al as described in U.S. Patent No. 5,677,572.
• Other useful cathode materials include, but are not limited to, those disclosed in U.S. Patent Nos. 5,059,861; 5,059,862; and 6,140,763.
• cathode 190 When light emission is viewed through cathode 190, it must be transparent or nearly transparent. For such applications, metals must be thin or one must use transparent conductive oxides, or a combination of these materials.
• Optically transparent cathodes have been described in more detail in U.S. Patent No. 5,776,623. Cathode materials can be deposited by evaporation, sputtering, or chemical vapor deposition. When needed, patterning can be achieved through many well known methods including, but not limited to, through-mask deposition, integral shadow masking as described in U.S. Patent No. 5,276,380 and EP 0 732 868, laser ablation, and selective chemical vapor deposition.
• Cathode materials can be deposited by evaporation, sputtering, or chemical vapor deposition. When needed, patterning can be achieved through many well known methods including, but not limited to, through-mask deposition, integral shadow masking as described in U.S. Patent No. 5,276,380 and EP 0 732 868, laser ablation, and selective chemical vapor deposition. PARTS LIST
• OLED device substrate anode hole-injecting layer hole-transporting layer light-emitting layer electron-transporting layer electron-injecting layer organic layers cathode

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