WO2002090466A1 - Dispositifs electroluminescents - Google Patents

Dispositifs electroluminescents Download PDF

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Publication number
WO2002090466A1
WO2002090466A1 PCT/GB2002/002094 GB0202094W WO02090466A1 WO 2002090466 A1 WO2002090466 A1 WO 2002090466A1 GB 0202094 W GB0202094 W GB 0202094W WO 02090466 A1 WO02090466 A1 WO 02090466A1
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metal
electroluminescent device
electrode
layer
silicon
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PCT/GB2002/002094
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English (en)
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Poopathy Kathirgamanathan
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Elam-T Limited
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Priority claimed from GB0111000A external-priority patent/GB0111000D0/en
Priority claimed from GB0110995A external-priority patent/GB0110995D0/en
Application filed by Elam-T Limited filed Critical Elam-T Limited
Publication of WO2002090466A1 publication Critical patent/WO2002090466A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/06—Luminescent, e.g. electroluminescent, chemiluminescent materials containing organic luminescent materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/30—Coordination compounds
    • 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
    • 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
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/30—Coordination compounds
    • H10K85/321—Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3]
    • H10K85/324—Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3] comprising aluminium, e.g. Alq3
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/611—Charge transfer complexes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/615—Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
    • H10K85/621—Aromatic anhydride or imide compounds, e.g. perylene tetra-carboxylic dianhydride or perylene tetracarboxylic di-imide
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/60—Organic compounds having low molecular weight
    • H10K85/631—Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine

Definitions

  • the present invention relates to a method of forming electroluminescent devices.
  • Liquid crystal devices and devices which are based on inorganic semiconductor systems are widely used, however these suffer from the disadvantages of high energy consumption, high cost of manufacture, low quantum efficiency and the inability to make flat panel displays.
  • Organic polymers have been proposed as useful in electroluminescent devices, but it is not possible to obtain pure colours, they are expensive to make and have a relatively low efficiency.
  • aluminium quinolate Another compound which has been proposed is aluminium quinolate, but this requires dopants to be used to obtain a range of colours and has a relatively low efficiency.
  • Patent application WO98/58037 describes a range of lanthanide complexes which can be used in electroluminescent devices which have improved properties and give better results.
  • Patent Applications PCT/GB98/01773, PCT/GB99/03619, PCT/GB99/04030, PCT/GB99/04024, PCT/GB99/04028, PCT/GB00/00268 describe electroluminescent complexes, structures and devices using rare earth chelates.
  • US Patent 5128587 discloses an electroluminescent device which consists of an organometallic complex of rare earth elements of the lanthanide series sandwiched between a transparent electrode of high work function and a second electrode of low work function with a hole conducting layer interposed between the electroluminescent layer and the transparent high work function electrode and an electron conducting layer interposed between the electroluminescent layer and the electron injecting low work function anode.
  • the hole conducting layer and the electron conducting layer are required to improve the working and the efficiency of the device.
  • the hole transporting layer serves to transport holes and to block the electrons, thus preventing electrons from moving into the electrode without recombining with holes. The recombination of carriers therefore mainly takes place in the emitter layer.
  • the invention provides an electroluminescent device comprising (i) a first electrode, (ii) a layer of a rare earth chelate electroluminescent compound and (iii) a second electrode in which one of the electrodes comprises silicon.
  • the silicon electrode can function as an anode or as a cathode in use or both the anode and cathode can comprise silicon.
  • the layer of the electroluminescent compound can be formed directly on the silicon layer or optionally there can be intermediate layers as described below.
  • the silicon electrode functions as a cathode optionally there is a layer of an electron injecting material between the silicon cathode and the electroluminescent material layer, as described below.
  • a layer of a metal fluoride such as an alkali metal, rare earth metal or their alloys and preferably lithium fluoride on the silicon cathode for example by having a metal fluoride layer deposited on the silicon.
  • the first electrode is a transparent substrate such as a conductive glass e.g. glass coated with indium tin oxide, antimony oxide, indium antimony oxide, cadmium oxide cadmium tin oxide.or plastic material which acts as the anode
  • a transparent substrate such as a conductive glass e.g. glass coated with indium tin oxide, antimony oxide, indium antimony oxide, cadmium oxide cadmium tin oxide.or plastic material which acts as the anode
  • preferred substrates are conductive glasses such as indium tin oxide coated glass, but any glass which is conductive or has a conductive layer such as a metal or conductive polymer can be used. Conductive polymers and conductive polymer coated glass or plastics materials can also be used as the substrate.
  • an indium tin oxide coated glass can act as the anode and light is emitted through the anode.
  • the silicon anode can be a thin layer of silicon which is transparent and can be in contact with the electroluminescent layer directly or through a layer such as a layer of a hole transporting material as described below.
  • the silicon anode can be formed on a transparent substrate such as a conductive glass or plastic material, preferred substrates are conductive glasses such as indium tin oxide coated glass, but any glass which is conductive or has a conductive layer such as a metal or conductive polymer can be used. Conductive polymers and conductive polymer coated glass or plastics materials can also be used as the substrate.
  • the cathode is silicon an n-type silicon can be used and when the anode is silicon a p-type silicon can be used.
  • the silicon layer is opaque i.e. it is too thick to be transparent, the light is emitted from the device around the edges of the silicon and interdigitated structures are preferred e.g. the electrode is formed of strips of the silicon.
  • the cathode can be formed of a transparent electrode which has a suitable work function, for example by a indium zinc oxide coated glass in which the indium zinc oxide has a low work function.
  • the anode can have a transparent coating of a metal formed on it to give a suitable work function. These devices are sometimes referred to as top emitting devices or back emitting devices.
  • the cathode can be a transparent thin layer of a metal such as gold, platinum etc. with a suitable work function or a work function adjusted to a suitable value.
  • the preferred electroluminescent materials are preferably rare earth chelates.
  • Rare earth chelates are known which fluoresce in ultra violet radiation and A. P. Sinha (Spectroscopy of Inorganic Chemistry Vol. 2 Academic Press 1971) describes several classes of rare earth chelates with various monodentate and bidentate ligands.
  • Group III A metals and lanthanides and actinides with aromatic complexing agents have been described by G. Kallistratos (Chimica Chronika, New Series, 11, 249-266 (1982)). This reference specifically discloses the Eu (III), Tb (III), U (III) and U (IV) complexes of diphenyl-phosponamidotriphenyl-phosphoran.
  • EP 0744451A1 also discloses fluorescent chelates of transition or lanthanide or actinide metals and the known chelates which can be used are those disclosed in the above references including those based on diketone and triketone moieties.
  • electroluminescent compounds which can be used as the electroluminescent materials in the present invention are of general formula (L ⁇ ) n M where M is a rare earth, lanthanide or an actinide, L ⁇ is an organic complex and n is the valence state of M.
  • Preferred electroluminescent compounds which can be used in the present invention are of formula
  • L ⁇ and Lp are organic ligands
  • M is a rare earth, transition metal, lanthanide or an actinide and n is the valence state of the metal M.
  • the ligands L ⁇ can be the same or different and there can be a plurality of ligands Lp which can be the same or different.
  • (L 1 )(L 2 )(L 3 )(L..)M (Lp) where M is a rare earth, transition metal, lanthanide or an actinide and (L (L 2 )(L 3 )(L...) are the same or different organic complexes and (Lp) is a neutral ligand.
  • the total charge of the ligands (L ⁇ )(L 2 )(L 3 )(L.. is equal to the valence state of the metal M.
  • the complex has the formula (L ! )(L 2 )(L 3 )M (Lp) and the different groups (L ! )(L 2 )(L 3 ) may be the same or different
  • Lp can be monodentate, bidentate or polydentate and there can be one or more ligands Lp.
  • M is metal ion having an unfilled inner shell and the preferred metals are selected from Sm(III), Eu(II), Eu(III), Tb(IH), Dy(III), Yb(III), Lu(III), Gd (III), U(III), U(VI)O 2 , Tm(III), Th(IV) 5 Ce (III), Ce(IV), Pr(II ⁇ ), Nd(III), Pm(i ⁇ ), Dy( ⁇ i), Ho(III), Er(III) and more preferably Eu(III), Tb(III), Dy(II ⁇ ), Gd (III).
  • electroluminescent compounds which can be used in the present invention are of general formula (L ⁇ ) n MjM 2 where M ⁇ is the same as M above, M 2 is a non rare earth metal, L ⁇ is a as above and n is the combined valence state of M] and M 2 .
  • the complex can also comprise one or more neutral ligands Lp so the complex has the general formula (L ⁇ ) n Mj M 2 (Lp), where Lp is as above.
  • the metal M 2 can be any metal which is not a rare earth, transition metal, lanthanide or an actinide examples of metals which can be used include lithium, sodium, potassium, rubidium, caesium, beryllium, magnesium, calcium, strontium, barium, copper (I), copper (II), silver, gold, zinc, cadmium, boron, aluminium, gallium, indium, germanium, tin (II), tin (IV), antimony (II), antimony (IV), lead (II), lead (IV) and metals of the first, second and third groups of transition metals in different valence states e.g.
  • organometallic complexes which can be used in the present invention are binuclear, trinuclear and polynuclear organometallic complexes e.g. of formula
  • L is a bridging ligand and where Mi is a rare earth metal and M 2 is Mj or a non rare earth metal, Lm and Ln are the same or different organic ligands L ⁇ as defined above, x is the valence state of M ⁇ and y is the valence state of M 2 .
  • trinuclear there are three rare earth metals joined by a metal to metal bond i.e. of formula (Lm) ⁇ M M. (Ln ) y — M 2 ( L p ) 2
  • M . , M 2 and M 3 are the same or different rare earth metals and Lm
  • Ln and Lp are organic ligands L ⁇ and x is the valence state of Mi
  • y is the valence state of M 2
  • z is the valence state of M 3
  • Lp can be the same as Lm and Ln or different.
  • the rare earth metals and the non rare earth metals can be joined together by a metal to metal bond and/or via an intermediate bridging atom, ligand or molecular group.
  • the metals can be linked by bridging ligands e.g.
  • L is a bridging ligand
  • polynuclear is meant there are more than three metals joined by metal to metal bonds and/or via intermediate ligands
  • M M 3 where Mi, M 2 , M 3 and M 4 are rare earth metals and L is a bridging ligand.
  • the metal M 2 can be any metal which is not a rare earth, transition metal, lanthanide or an actinide examples of metals which can be used include lithium, sodium, potassium, rubidium, caesium, beryllium, magnesium, calcium, strontium, barium, copper, silver, gold, zinc, cadmium, boron, aluminium, gallium, indium, germanium, tin, antimony, lead, and metals of the first, second and third groups of transition metals e.g.
  • L ⁇ is selected from ⁇ diketones such as those of formulae
  • R 1; R and R 3 can be the same or different and are selected from hydrogen, and substituted and unsubstituted hydrocarbyl groups such as substituted and unsubstituted aliphatic groups, substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups; R 1; R 2 and R 3 can also form substituted and unsubstituted fused aromatic, heterocyclic and polycyclic ring structures and can be copolymerisable with a monomer e.g. styrene.
  • X is Se, S or O
  • Y can be hydrogen, substituted or unsubstituted hydrocarbyl groups, such as substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorine, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups or nitrile.
  • R] and/or R 2 and/or R 3 include aliphatic, aromatic and heterocyclic alkoxy, aryloxy and carboxy groups, substituted and substituted phenyl, fluorophenyl, biphenyl, phenanthrene, anthracene, naphthyl and fluorene groups alkyl groups such as t-butyl, heterocyclic groups such as carbazole.
  • Some of the different groups L ⁇ may also be the same or different charged groups such as carboxylate groups so that the group L ⁇ can be as defined above and the groups L 2 , L 3 . .. can be charged groups such as
  • Ri R and R 3 can also be
  • X is O, S, Se orNH.
  • a preferred moiety Ri is trifluoromethyl CF 3 and examples of such diketones are, banzoyltrifluoroacetone, p-chlorobenzoyltrifluoroacetone, p-bromotrifluoroacetone, p-phenyltrifluoroacetone, 1 -naphthoyltrifluoroacetone, 2-naphthoyltrifluoroacetone, 2-phenathoyltrifluoroacetone, 3-phenanthoyltrifluoroacetone, 9- anthroyltrifluoroacetonetrifluoroacetone, cinnamoyltrifluoroacetone, and 2- thenoyltrifluoroacetone.
  • the different groups L ⁇ may be the same or different ligands of formulae
  • the different groups L ⁇ may be the same or different quinolate derivatives such as where R is hydrocarbyl, aliphatic, aromatic or heterocyclic carboxy, aryloxy, hydroxy or alkoxy e.g. the 8 hydroxy quinolate derivatives or
  • R 5 is a substituted or unsubstituted aromatic, polycyclic or heterocyclic ring a polypyridyl group
  • R 5 can also be a 2-ethyl hexyl group so L n is 2-ethylhexanoate or R 5 can be a chair structure so that L n is 2-acetyl cyclohexanoate or L ⁇ can be
  • R is as above e.g. alkyl, allenyl, amino or a fused ring such as a cyclic or polycyclic ring.
  • the different groups L ⁇ may also be
  • the groups Lp can be selected from
  • each Ph which can be the same or different and can be a phenyl (OPNP) or a substituted phenyl group, other substituted or unsubstitated aromatic group, a substituted or unsubstitated heterocyclic or polycyclic group, a substitated or unsubstitated fused aromatic group such as a naphthyl, anthracene, phenanthrene or pyrene group.
  • the substituents can be for example an alkyl, aralkyl, alkoxy, aromatic, heterocyclic, polycyclic group, halogen such as fluorine, cyano, amino. Substitated amino etc. Examples are given in figs.
  • R, R 1; R 2; R 3 and R 4 can be the same or different and are selected from hydrogen, hydrocarbyl groups, substitated and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups; R, R 1; R ; R 3 and R 4 can also form substitated and unsubstituted fused aromatic, heterocyclic and polycyclic ring structures and can be copolymerisable with a monomer e.g. styrene.
  • R, Ri, R 2j R 3 and R 4 can also be unsaturated alkylene groups such as vinyl groups or groups
  • L p can also be compounds of formulae
  • R ls R 2 and R 3 are as referred to above.
  • L p can also be
  • L p chelates are as shown in figs. 4 and fluorene and fluorene derivatives e.g. a shown in figs. 5 and compounds of formulae as shown as shown in figs. 6 to 8.
  • L ⁇ and Lp are tripyridyl and TMHD, and TMHD complexes, ⁇ , ⁇ ', ⁇ " tripyridyl, crown ethers, cyclans, cryptans phthalocyanans, porphoryins ethylene diamine tetramine (EDTA), DCTA, DTPA and TTHA.
  • TMHD 2,2,6,6-tetramethyl-3,5-heptanedionato
  • OPNP is diphenylphosphonimide triphenyl phosphorane.
  • the formulae of the polyamines are shown in fig. 9.
  • electroluminescent materials which can be used include metal quinolates such as lithium quinolate, and non rare earth metal complexes such as aluminium, magnesium, zinc and scandium complexes such as complexes of ⁇ -diketones e.g. Tris -(l,3-diphenyl-l-3-propanedione) (DBM) and suitable metal complexes are A1(DBM) 3, Zn(DBM) 2 and Mg(DBM) 2 ., Sc(DBM) 3 etc.
  • metal quinolates such as lithium quinolate
  • non rare earth metal complexes such as aluminium, magnesium, zinc
  • scandium complexes such as complexes of ⁇ -diketones e.g. Tris -(l,3-diphenyl-l-3-propanedione) (DBM)
  • suitable metal complexes are A1(DBM) 3, Zn(DBM) 2 and Mg(DBM) 2 ., Sc(DBM) 3 etc.
  • the hole transporting layer serves to transport holes and to block the electrons, thus preventing electrons from moving into the electrode without recombining with holes.
  • the recombination of carriers therefore mainly takes place in the emitter layer.
  • the hole transporting material can be an amine complex such as poly (vinylcarbazole), N, N'-diphenyl-N, N'-bis (3-methylphenyl) -1,1' -biphenyl -4,4'- diamine (TPD), an unsubstituted or substituted polymer of an amino substitated aromatic compound, a polyaniline, substitated polyanilines, polythiophenes, substitated polythiophenes, polysilanes etc.
  • polyanilines are polymers of
  • R is in the ortho - or meta-position and is hydrogen, Cl-18 alkyl, Cl-6 alkoxy, amino, chloro, bromo, hydroxy or the group
  • R is alky or aryl and R' is hydrogen, Cl-6 alkyl or aryl with at least one other monomer of formula I above.
  • the hole transporting material can be a polyaniline
  • polyanilines which can be used in the present invention have the general formula
  • XXVII where p is from 1 to 10 and n is from 1 to 20, R is as defined above and X is an anion, preferably selected from CI, Br, SO , BF , PF 6 , H PO 3 , H 2 PO 4 , arylsulphonate, arenedicarboxylate, polystyrenesulphonate, polyacrylate alkysulphonate, vinylsulphonate, vinylbenzene sulphonate, cellulose sulphonate, camphor sulphonates, cellulose sulphate or a perfluorinated polyanion.
  • arylsulphonates are p-toluenesulphonate, benzenesulphonate, 9,10- anthraquinone-sulphonate and anthracenesulphonate, an example of an arenedicarboxylate is phthalate and an example of arenecarboxylate is benzoate.
  • evaporable deprotonated polymers of unsubstitated or substitated polymer of an amino substitated aromatic compound are used.
  • the de-protonated unsubstituted or substituted polymer of an amino substituted aromatic compound can be formed by deprotonating the polymer by treatment with an alkali such as ammonium hydroxide or an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide.
  • the degree of protonation can be controlled by forming a protonated polyaniline and de-protonating.
  • Methods of preparing polyanilines are described in the article by A. G. MacDiarmid and A. F. Epstein, Faraday Discussions, Chem Soc.88 P319 1989.
  • the conductivity of the polyaniline is dependant on the degree of protonation with the maximum conductivity being when the degree of protonation is between 40 and 60% e.g. about 50% for example.
  • the polymer is substantially fully deprotonated
  • a polyaniline can be formed of octamer units i.e. p is four e.g.
  • the polyanilines can have conductivities of the order of 1 x 10 "1 Siemen cm "1 or higher.
  • the aromatic rings can be unsubstituted or substitated e.g. by a CI to 20 alkyl group such as ethyl.
  • the polyaniline can be a copolymer of aniline and preferred copolymers are the copolymers of aniline with o-anisidine, m-sulphanilic acid or o-aminophenol, or o- toluidine with o-aminophenol, o-ethylaniline, o-phenylene diamine or with amino anthracenes.
  • Other polymers of an amino substitated aromatic compound which can be used include substituted or unsubstitated polyaminonapthalenes, polyaminoanthracenes, polyaminophenanthrenes, etc. and polymers of any other condensed polyaromatic compound. Polyaminoanthracenes and methods of making them are disclosed in US Patent 6,153,726.
  • the aromatic rings can be unsubstituted or substituted e.g. by a group R as defined above.
  • conjugated polymer and the conjugated polymers which can be used can be any of the conjugated polymers disclosed or referred to in US 5807627, PCT/WO90/13148 and PCT/WO92/03490.
  • the preferred conjugated polymers are poly (p-phenylenevinylene)-PPV and copolymers including PPV.
  • Other preferred polymers are poly(2,5 dialkoxyphenylene vinylene) such as poly (2-methoxy-5-(2-methoxypentyloxy-l,4-phenylene vinylene), poly(2-methoxypentyloxy)- 1 ,4-phenylenevinylene) , poly(2-methoxy-5 -(2- dodecyloxy-l,4-phenylenevinylene) and other poly(2,5 dialkoxyphenylenevinylenes) with at least one of the alkoxy groups being a long chain solubilising alkoxy group, poly fluorenes and oligofluorenes, polyphenylenes and oligophenylenes, polyanthracenes and oligo anthracenes, ploythiophenes and oligothiophenes.
  • the phenylene ring may optionally carry one or more substituents e.g. each independently selected from alkyl, preferably methyl, alkoxy, preferably methoxy or ethoxy.
  • Any poly(arylenevinylene) including substitated derivatives thereof can be used and the phenylene ring in poly(p-phenylenevinylene) may be replaced by a fused ring system such as anthracene or naphthlyene ring and the number of vinylene groups in each polyphenylenevinylene moiety can be increased e.g. up to 7 or higher.
  • the conjugated polymers can be made by the methods disclosed in US 5807627, PCT/WO90/13148 and PCT/WO92/03490.
  • the thickness of the hole transporting layer is preferably 20nm to 200nm.
  • polymers of an amino substitated aromatic compound such as polyanilines referred to above can also be used as buffer layers with or in conjunction with other hole transporting materials.
  • R 1; R 2 and R 3 can be the same or different and are selected from hydrogen, and substituted and unsubstituted hydrocarbyl groups such as substitated and unsubstituted aliphatic groups, substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups; Ri , R 2 and R 3 can also form substituted and unsubstituted fused aromatic, heterocyclic and polycyclic ring structures and can be copolymerisable with a monomer e.g.
  • styrene X is Se, S or O
  • Y can be hydrogen, substituted or unsubstitated hydrocarbyl groups, such as substitated and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorine, fluorocarbons such as trifluoryl methyl groups, halogens such as fluorine or thiophenyl groups or nitrile.
  • Ri and/or R 2 and or R 3 examples include aliphatic, aromatic and heterocyclic alkoxy, aryloxy and carboxy groups, substitated and substitated phenyl, fluorophenyl, biphenyl, phenanthrene, anthracene, naphthyl and fluorene groups alkyl groups such as t-butyl, heterocyclic groups such as carbazole.
  • the electron injecting material is a material which will transport electrons when an electric current is passed through electron injecting materials include a metal complex such as a metal quinolate e.g. an aluminium quinolate, lithium quinolate, a cyano anthracene such as 9,10 dicyano anthracene, cyano substitated aromatic compounds, tetracyanoquinidodimethane a polystyrene sulphonate or a compound with the structural formulae shown in figure 10 of the drawings in which the phenyl rings can be substitated with substituents R as defined above.
  • the electron injecting material can be mixed with the electroluminescent material and co-deposited with it.
  • the cathode can be any low work function metal e.g. aluminium, calcium, lithium, silver/magnesium alloys, rare earth metal alloys etc., aluminium is a preferred metal.
  • a metal fluoride such as an alkali metal, rare earth metal or their alloys can be used as the second electrode for example by having a metal fluoride layer formed on a metal.
  • the metal electrode may consist of a plurality of metal layers, for example a higher work function metal such as aluminium deposited on the substrate and a lower work function metal such as calcium deposited on the higher work function metal.
  • a further layer of conducting polymer lies on top of a stable metal such as aluminium.
  • the hole transporting material can be mixed with the electroluminescent material and co-deposited with it.
  • the hole transporting materials, the electroluminescent material and the electron injecting materials can be mixed together to form one layer, which simplifies the construction.
  • the display of the invention may be monochromatic or polychromatic.
  • Electroluminescent rare earth chelate compounds are known which will emit a range of colours e.g. red, green, and blue light and white light and examples are disclosed in Patent Applications WO98/58037 PCT/GB98/01773, PCT/GB99/03619, PCT/GB99/04030, PCT/GB99/04024, PCT/GB99/04028, PCT/GB00/00268 and can be used to form OLEDs emitting those colours.
  • Either or both electrodes can be formed of silicon and the electroluminescent material and intervening layers of a hole transporting and electron transporting materials can be formed on the silicon substrate.
  • Alternative arrangements can comprise sequentially a silicon cathode : layer electron transmitting material : layer of electroluminescent material : layer of hole transporting material : anode, silicon : layer electron transmitting material : layer of electroluminescent material : layer of hole transporting material : silicon anode.
  • silicon cathode layer electron transmitting material : layer of electroluminescent material : layer of hole transporting material : silicon anode.
  • the silicon can be a porous silicon or a crystalline silicon and the surface of the silicon substrate may be polished or smoothed to produce a flat surface prior to the deposition of the adjacent layers.
  • a non-planarised silicon substrate can be coated with a layer of conducting polymer to provide a smooth, flat surface prior to deposition of further materials.
  • Figure 18 shows a device with a silicon anode in which (1) is a transparent cathode, (2) is a layer of an electron transmitting material (3) is a layer of the electroluminescent material (4) is a layer of the hole transporting material and (5) is the silicon anode.
  • (1) is a transparent cathode
  • (2) is a layer of an electron transmitting material
  • (3) is a layer of the electroluminescent material
  • (4) is a layer of the hole transporting material
  • (5) is the silicon anode.
  • An electroluminescent device was fabricated to this structure by depositing sequentially on an anode comprising crystalline p-type silicon, layers of a known terbium (III) green electroluminescent organo metal complex (70nm), and a layer of an aluminium quinolate as an electron transmitting layer (45nm).
  • an anode comprising crystalline p-type silicon
  • layers of a known terbium (III) green electroluminescent organo metal complex 70nm
  • a layer of an aluminium quinolate an electron transmitting layer
  • An indium gallium contact oxide coated glass as the cathode.
  • An indium gallium contact was formed on the silicon cathode.
  • the silicon anode was formed of a p-type silicon of orientation (100) of conductivity 0.1 S/cm and thickness 0.5mm. At a voltage above 9 volts green light was emitted through the ITO coated glass catho
  • Figure 18 shows a device with a silicon cathode in which (11) is a silicon cathode, (12) is a layer of an electron transmitting material (13) is a layer of the electroluminescent material (14) is a layer of the hole transporting material and (15) is the anode.
  • (11) is a silicon cathode
  • (12) is a layer of an electron transmitting material
  • (13) is a layer of the electroluminescent material
  • (14) is a layer of the hole transporting material
  • (15) is the anode.
  • An electroluminescent device was fabricated to this structure by depositing sequentially, on a cathode comprising crystalline n-type silicon, layers of an aluminium quinolate as an electron transmitting layer (20nm), a known terbium (III) green electroluminescent organo metal complex (80nm) based on Tb(III)(TMHD) 3 OPNP, TPD as a hole transporting layer (40nm) (the formula of TPD is shown in fig, 16) and an electrode comprising a layer of transparent gold on a transparent substrate.
  • An indium gallium contact was formed on the silicon cathode.
  • the silicon electrode was formed of an n-type silicon of orientation (100) of conductivity 200 S/cm and thickness 0.381mm. At a voltage above 6 volts green light was emitted through the gold electrode.
  • a plot of current density against bias voltage is shown in fig. 20.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

L'invention concerne une structure électroluminescente comprenant une anode, une couche d'un composé électroluminescent à base de métal chelaté et une cathode, la cathode et/ou l'anode étant en silicium. Cette structure comprend de préférence une couche constituée d'un matériau de transport de trous située entre l'anode et le composé électroluminescent et une couche constituée d'un matériau de transport d'électrons située entre le composé électroluminescent et la cathode en silicium.
PCT/GB2002/002094 2001-05-04 2002-05-07 Dispositifs electroluminescents WO2002090466A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB0110995.8 2001-05-04
GB0111000.6 2001-05-04
GB0111000A GB0111000D0 (en) 2001-05-04 2001-05-04 Electroluminescent devices
GB0110995A GB0110995D0 (en) 2001-05-04 2001-05-04 Electroluminiscent devices

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Publication number Priority date Publication date Assignee Title
US7211334B2 (en) 2001-07-09 2007-05-01 Oled-T Limited Electroluminescent materials and devices
US7235311B2 (en) 2001-04-20 2007-06-26 Oled-T Limited Electroluminescent devices incorporating mixed metal organic complexes
US7303824B2 (en) 2001-08-04 2007-12-04 Oled-T Limited Electroluminescent device
US7354661B2 (en) 2001-06-15 2008-04-08 Oled-T Limited Electroluminescent devices

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WO1992019084A1 (fr) * 1991-04-17 1992-10-29 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Dispositif en silicium electroluminescent
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7235311B2 (en) 2001-04-20 2007-06-26 Oled-T Limited Electroluminescent devices incorporating mixed metal organic complexes
US7354661B2 (en) 2001-06-15 2008-04-08 Oled-T Limited Electroluminescent devices
US7211334B2 (en) 2001-07-09 2007-05-01 Oled-T Limited Electroluminescent materials and devices
US7303824B2 (en) 2001-08-04 2007-12-04 Oled-T Limited Electroluminescent device

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