HK1130071A - Arylamine polymer - Google Patents

Description

Arylamine polymers

Technical Field

The present invention relates to arylamine polymers and to a process for their preparation. The present invention also relates to organic electronic devices, such as Light Emitting Devices (LEDs), containing the amine polymers and methods of making the same.

Background

Organic LEDs typically include one or more semiconducting polymer layers located between electrodes. Semiconducting polymers are characterized by partial or significant conjugation in the main and/or side chains.

Semiconducting polymers are now often used in polymer light emitting devices ("PLEDs"), as disclosed in WO 90/13148.

A typical LED includes an anode, a substrate on which the cathode is supported, and an organic light-emitting layer located between the anode and the cathode and including at least one light-emitting material. In operation, holes are injected into the device through the anode, and electrons are injected into the device through the cathode. The holes and electrons combine in the organic light-emitting layer to form excitons, which then undergo radiative decay to emit light. Other layers may be present within the LED. For example, a layer of a conducting organic hole injection material, such as poly (ethylene dioxythiophene)/polystyrene sulfonate (PEDT/PSS), may be provided between the anode and the organic light emitting layer to assist hole injection from the anode into the organic light emitting layer. In addition, a layer of a semiconducting organic hole transport material may be provided between the anode (or hole injection layer, if present) and the organic light emitting layer to assist hole transport into the organic light emitting layer.

In general, it is desirable that one or more of the polymers used in the aforementioned organic devices be soluble in a common organic solvent to facilitate their deposition during device fabrication. Many such polymers are known. One of the key advantages of this solubility is that the polymer layer can be made by solution processing, for example by spin-casting, ink-jet printing, screen printing, dip coating, roll printing, and the like. Examples of such polymers are disclosed in e.g. modern materials (adv. mater.)200012(23)1737-1750 and include polymers with at least partially conjugated backbones formed from aromatic or heteroaromatic units, such as fluorene, indenofluorene, phenylene, arylenevinylene, oxazole, quinoxaline, benzothiadiazole, oxadiazole, thiophene and arylamines with solubilizing groups, as well as polymers with non-conjugated backbones, such as poly (vinylcarbazole). Polyarylenes, such as polyfluorenes, have good film forming properties and can be readily formed by Suzuki (Suzuki) or Yamatomo (Yamatomo) polymerization, which enables a high degree of control over the regioregularity of the resulting polymer.

In some devices, it may be desirable to cast multiple layers, i.e., laminates, of different materials (typically polymers) on a single substrate surface. For example, this may enable independent functions such as electron or hole charge transport, luminescence control, photon confinement, exciton confinement, photo-induced charge generation, and optimization of charge blocking or storage.

In this regard, it is useful to be able to fabricate multiple layers of materials (e.g., polymers) in order to control, for example, electrical and optical properties across the device. This may be useful for optimal device performance. Optimal device performance can be achieved, for example, by careful design of the level offset (level offset) for electron and hole transport, mismatch in the photorefractive index, and mismatch in the energy gap at the interface. Such a heterogeneous structure (heterostructure) may, for example, facilitate one carrier injection but block the opposite carrier extraction and/or prevent exciton diffusion onto the quenching interface. Thus, such a heterogeneous structure may provide useful carrier and photon confinement effects.

WO99/54385 discloses copolymers containing fluorene and amine groups for use in electroluminescent devices. Disclosed are amine groups of formulae II, III, and IV:

amine-containing small molecules are also known in the field of LEDs and in fields other than LEDs, for example JP2004210785, JP2003248331, JP2002241352, WO2000/027946, JP11185967, JP10302960, JP10095787, JP09268284, JP07301926, JP06110228, JP06104467, EP506492, JP04225363, JP03094260, JP03094259, JP03094258, Journal of the Chemical Society, PerkinTransactions 2: physical Organic Chemistry (1997), (7), 1405-1414 and Chemical communicationsons (1996), (23), 2641-. According to "Approach to molecular design of charge transport materials by molecular organization calculation", IS&T｀s Int.Congr.Adv.Non-Impactprinting Technol.，Final Program Proc.，8^th(1992) 261-3, amine small molecules are also known.

Crosslinkable arylamine compounds are known from WO 2005/052027.

The light emitting layer of an LED may comprise one or more fluorescent and/or phosphorescent light emitting materials. In an LED, electrons and holes are injected from opposing electrodes and combine to form two types of excitons; the theoretical ratio is 3:1 for spin-symmetric triplet and spin-antisymmetric singlet. Radiation from the singlet state decays rapidly (fluorescence); but radiative decay from triplet states (phosphorescence) is formally suppressed by the requirement of spin conservation.

Driven by this understanding, the idea of transferring both singlet and triplet states to phosphorescent dopants was proposed, originally considering that the maximum internal quantum efficiency of Organic Light Emitting Devices (OLEDs) was limited to 25%. This phosphorescence enables ideal acceptance of singlet and triplet excitons from organic materials and generation of light, particularly electroluminescence from both.

Over the past several years, many have investigated the incorporation of phosphorescent materials into semiconductor layers. Good results have been achieved with LEDs based on blends incorporating phosphorescent dopants and a host (host), e.g., a host of small molecules or the like, or a non-conjugated polymer host, e.g., polyvinylcarbazole or the like.

In LEDs, carbazole compounds as hosts for triplet emitters are the subject of several papers, including JACS (american chemical society) 2004, 126, 7718 and JACS 2004, 126, 6035-. JACS 2004, 126, 7718 discloses homopolymers and copolymers based on 9,9 '-dialkyl- [3, 3' -dicarbazolyl. JACS 2004, 126, 6035-.

One of the reasons for the poor success of using polymer matrices in multi-color LEDs is the difficulty in finding materials with sufficiently high triplet energy levels so that the matrices do not quench the red, green and especially blue emission. Furthermore, as mentioned in JACS 2004, 126, 7718, a practical challenge is to prepare polymers with high triplet energy levels while at the same time having suitable HOMO and LUMO energy levels for efficient charge injection.

WO2004/055129 relates to electroluminescent devices comprising a combination of a charge transporting conjugated donor compound and a phosphorescent acceptor compound. Meta-linked phenylene groups are disclosed; 3, 6-linked fluorenylidene; and 3, 6-carbazolyl units as odd-integer sub-units to increase the lowest triplet level of the conjugated polymer chain.

In view of the above, it is understood that there is still a need to provide further host materials for phosphorescent light emitting materials within electronic devices.

As such, it is an object of the present invention to provide new host materials for phosphorescent light emitting materials within electronic devices. Furthermore, it is an object of the present invention to provide new electronic devices comprising new matrix materials. Still further, it is an object of the present invention to provide a process for the preparation thereof.

A first aspect of the invention provides a semiconductive polymer comprising in the polymer backbone a first repeat unit comprising formula 1:

wherein a is 1 or 2; b is 0 or 1; and c is 0, 1 or 2, with the proviso that if c is 0, then b is 0; ar (Ar)₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆Each independently represents an aromatic or heteroaromatic ring, or a fused derivative thereof; characterized in that Ar is₁、Ar₂、Ar₄And Ar₅At least one of which is not conjugated; and with the proviso that (a) when a is 1, then Ar₁Not by direct chemical bond to Ar₂And (b) when b is 1 and c is 1, then Ar₄Not by direct chemical bond to Ar₅And (c) when b is 0 and c is 1, then Ar₂Not by direct chemical bond to Ar₅And (d) when a is 2, then Ar₁The radicals are not linked by a single bond, and (e) if c is 2, then Ar₅The groups are not connected by single bonds.

Preferably, a-1 and c-0 or 1.

The first aspect further provides the use of a semiconducting polymer to transport holes in an organic electronic device. The first aspect still further provides the use of a semiconducting polymer as a matrix for a phosphorescent metal complex in an organic electronic device.

The inventors have found that introducing a first repeat unit of formula 1 into a semiconducting polymer and thus reducing the conjugation length along the polymer backbone will increase the triplet energy level of the semiconducting polymer. This would be beneficial to avoid quenching when semiconducting polymers are used as hosts for phosphorescent materials in light emitting devices, thereby increasing device efficiency. Preferably, the triplet energy level is sufficiently high so that the semiconducting polymer is suitable for use as a matrix for a phosphorescent green emitter. In this regard, the triplet energy level is preferably greater than 2.4 electron volts. In another embodiment, the semiconducting polymer is suitable for use as a matrix for phosphorescent sky-blue emitters and preferably has a triplet energy level greater than 2.6 electron volts. In another embodiment, the semiconducting polymer is suitable for use as a host for phosphorescent red emitters and preferably has a triplet energy level greater than 2.2 electron volts. The hole transport properties of semiconducting polymers also make the polymers desirable hole transport materials for use in organic electronic devices.

It has also been found that the semiconducting polymers of the present invention have unexpectedly good stability when compared to other matrix materials. Stability was measured in terms of electrochemical stability (reversible oxidation and reduction) and lifetime of the device according to standard techniques.

A second aspect of the invention provides a monomer for the preparation of a polymer as defined in relation to the first aspect, said monomer comprising formula 1:

wherein a, b, c, Ar₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆As defined above with respect to the first aspect; and at least one leaving group L directly with Ar₁Are linked and can participate in the polymerization.

A third aspect of the invention provides a method of preparing a semiconductive polymer as defined with respect to the first aspect, the method comprising the step of polymerising a plurality of monomers as defined with respect to the second aspect under conditions which facilitate formation of the semiconductive polymer.

A fourth aspect of the invention provides an organic electronic device comprising a semiconductive polymer as defined in relation to the first aspect. The fourth aspect further provides a method for preparing the same.

The invention is described in more detail with reference to the accompanying drawings, in which:

fig. 1 shows the basic device structure for an LED.

With reference to the first aspect, Ar will be understood₁、Ar₂、Ar₄And Ar₅By at least one of "non-conjugated" is meant non-conjugated along the backbone of the first repeat unit. Conjugation results from successive overlaps along the backbone orbitals, such as alternating single and double carbon bonds, which will leave a continuous path of overlapping p orbitals. An example of a conjugated backbone is poly (p-linked phenylene).

Ar₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆May be selected from any suitable aryl or heteroaryl ring or fused derivatives thereof. Suitable aryl and heteroaryl rings are known to those skilled in the art and include, in the following order of preference: phenyl, naphthyl, fluorene, biphenyl, carbazole, and any 6-membered heterocyclic ring having a suitable triplet energy level for green phosphorescent emitters. Planar rings, such as phenyl or fluorene rings, are preferred. Aromatic rings are preferred. Preferably a 6 membered ring.

Ar₁、Ar₂、Ar₃、Ar₄、Ar₅And/or Ar₆May be substituted or unsubstituted. Suitable substituents include solubilising groups, for example straight or branched C_1-20Alkyl or alkoxy; electron withdrawing groups such as fluorene, nitro or cyano; and substituents that increase the glass transition temperature (Tg) of the polymer.

Ar₃And/or Ar₄Another suitable substituent of (a) is an amino group, preferably a diarylamino group, to provide amine units within the polymer backbone and pendant amine units of the polymer backbone that can serve to improve the hole transport and/or emission characteristics of the polymer. Amino groups may be directly substituted with Ar₃And/or Ar₄Attached to, or Ar may be separated by a spacer₃And/or Ar₄. The aryl group in the diarylamino substituent may be substituted with the above for Ar₁-Ar₆The same is said.

Additional linkages not shown in formula 1 may be present between the backbone and the pendant Ar ring. In this regard, Ar₁Can be reacted with Ar₃Are connected. Similarly, Ar₂Can be reacted with Ar₃Are connected. If c is 1, then Ar₅Can be reacted with Ar₆Are connected. If b is 1 and c is 1, then Ar₄Can be reacted with Ar₆Are connected. If b is 0 and c is 1, then Ar₂Can be reacted with Ar₆Are connected. All of the foregoing linkages may be direct chemical bonds or via bridging groups or atoms.

One or more of the aforementioned linkages may be present. In particular, Ar₂Can be reacted with Ar₃And Ar₆Both phases areEven, as shown below:

this repeat unit can be derived from monomers prepared from small molecules as disclosed in the journal of heterocyclic chemistry (j. heterocyclic Chem.), 29, 1237 (1992).

Ar₁Not by direct chemical bond to Ar₂Are connected. However, Ar₁May be linked to Ar via a bridging group or atom₂Are connected.

Similarly, if b ═ 1 and c ═ 1, then Ar₄Not by direct chemical bond to Ar₅Are connected. And, when b is 0 and c is 1, Ar is₂Not by direct chemical bond to Ar₅Are connected. However, if b-1 and c-1, then Ar₄May be linked to Ar via a bridging group or atom₅Are connected. Similarly, Ar if b ═ 0 and c ═ 1₂May be linked to Ar via a bridging group or atom₅Are connected. Further, in the case where a is 2, two Ar are₁The radicals are not linked by a direct chemical bond, and in the case where c ═ 2, two Ar' s₅The radicals are not linked by direct chemical bonds.

These possibilities are shown in the following formulas 3-5:

wherein- - -represents a direct chemical bond, X represents a bridging group or a bridging atom; and d is 0 or 1. Suitable bridging groups include (CH)₂)_nWherein n is 1-2. Suitable bridging atoms include O and S. In the general formulae 3 to 5, there may be- -X- -and- - (X) as shown_d-one or a combination of linking groups.

Preferably, Ar₃And/or Ar₆If present, has at least one substituent. Preferably Ar₃And/or Ar₆Independently (if present) represents an aromatic or heteroaromatic ring. When Ar is₃And/or Ar₆When representing a 6-membered ring such as phenyl, Ar₃And/or Ar₆May have up to 5 substituents. Preferably at least one substituent in the para position.

Preferably, Ar₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆Each comprising a phenyl group, which may be substituted or unsubstituted. For ease of synthesis, in Ar₂And Ar₄Substitution on in preference to Ar₁And Ar₅. If the structural unit [ -N-Ar2-Ar4-N-]Conjugated along its length, then when Ar is₂＝Ar₄In the case of a 6-membered ring, substitution in the 2, 2 'or 3, 3' position is preferred. This will increase the torque along the polymer backbone, thereby further reducing conjugation.

When Ar is₁、Ar₂、Ar₄And/or Ar₅When a phenyl group is included, the phenyl group may be attached at the meta position within the first repeat unit, or may be fused at the meta position to another aryl or heteroaryl ring, such as another phenyl group, in order to render it non-conjugated.

The meta-linked benzene ring includes formula 6:

the substituents may be in the para position of the phenyl ring attached in the meta position:

wherein R represents any suitable substituent described herein. Preferred substituents include alkyl, alkoxy and aryl, with alkyl and alkoxy being most preferred.

Fused derivatives of phenyl rings include formula 8, wherein Ar₇Represents any suitable second aromatic or heteroaryl ring:

second aromatic or heteroaryl ring Ar₇Preferably a 6 membered ring, more preferably phenyl. Fused derivatives may include formula 9:

non-fused, non-conjugated aromatic or heteroaryl rings or fused derivatives thereof are preferred.

In one embodiment, the terminal group Ar (i.e., Ar) of the first repeat unit₁And Ar₂And Ar₅One) is preferably non-conjugated. In this embodiment, two terminal groups Ar (i.e., Ar)₁And Ar₂And Ar₅One) preferably each independently represent a phenyl group linked in the meta position.

The first repeat unit may comprise formula 10 or 11 or 12:

wherein R represents hydrogen or any suitable substituent described herein. Preferred substituents include alkyl, alkoxy and aryl. Alkyl and alkoxy groups are most preferred.

In formula 10, the- -X- -linkage is optional. If present, X is preferably O or S.

In formula 12, it may be desirable to increase the degree of torque within the polymer chain by introducing substituents as shown in formula 13:

when c is 1, in one embodiment, the center Ar (i.e., Ar) in the first repeat unit₂And Ar₄One or both) are preferably non-conjugated. In this embodiment, Ar₂And Ar₄One or both preferably independently represent a meta-linked phenyl group.

In one embodiment, Ar is 0 when c ═ 1 and b ═ 0₂Preferably represents a meta-linked phenyl group.

The first repeat unit can include formula 14:

wherein- - -represents a direct chemical bond; each X independently represents a bridging group or a bridging atom; c is 0 or 1; each R independently represents a substituent and — (X)_d-the linking group is independently optional.

In another embodiment, Ar is 0 when c ═ 1 and b ═ 0₂Fused derivatives representing benzene rings are preferred. The fused derivative may have the general formula 8 or 9 as defined herein. If condensed Ar₁And Ar₅Then Ar is₂Must be meta-linked (and a ═ 0).

The first repeat unit may comprise formula 15:

wherein- - - -represents a direct chemical bond(ii) a Each X independently represents a bridging group or a bridging atom; d is 0 or 1; each R independently represents a substituent and — (X)_d-the linking group is independently optional.

The first repeat unit defined above may be functionalized so as to crosslink the semiconductive polymer. When the semiconducting polymer is crosslinked, preferably the semiconducting polymer contains 5 to 25 mole% crosslinked repeat units.

At Ar₃And/or Ar₆The substituent(s) on (e.g., one or both R in formulas 10-12, 14 or 15) may be functional substituents, thereby providing for crosslinking of another polymer chain.

The semiconducting polymer is preferably soluble so that it can be deposited in layers by solution processing, for example by inkjet printing, spin coating or roll printing. The semiconducting polymer is preferably soluble in common organic solvents, such as alkylated benzenes, especially xylene and toluene.

The semiconducting polymer preferably comprises conjugated segments separated by non-conjugated aromatic or heteroaryl rings or fused derivatives thereof. By "non-conjugated" is meant that the groups on either side of the non-conjugated aromatic or heteroaryl ring or fused derivatives thereof are not conjugated to each other:

if B is not conjugated, then A and C are not conjugated to each other. This is in contrast to conjugated aromatic or heteroaryl rings or fused derivatives thereof, in which the groups on either side are conjugated to one another.

In one embodiment, the semiconducting polymer is substantially non-conjugated.

The semiconducting polymer may comprise a homopolymer.

The semiconductive polymer may comprise a copolymer or a higher order (order) polymer. Copolymers or higher order polymers contain one or more different co-repeat units in addition to the first repeat unit as defined herein.

When a copolymer or higher order polymer is intended for use as a hole transport polymer, preferably the copolymer or higher order polymer contains at least 50 mole% of the first repeat unit. When a copolymer or higher order polymer is intended for use as a matrix, the copolymer or higher order polymer may contain up to 50 mole percent of the first repeat unit if one or more of the co-repeat units are not conjugated. More preferably, the copolymer or higher order polymer contains from 5 to 50 mole%, still more preferably from 5 to 25 mole%, of the first repeat unit.

The co-repeat unit may assist in dissolving the semiconducting polymer.

Preferred co-repeat units may include aryl or heteroaryl groups. Suitable aryl and heteroaryl groups include fluorenes, especially 9, 9-dialkylpolyfluorenes or 9, 9-diarylpolyfluorenes; spirofluorene; an indenofluorene; a phenylene group; thiophene; a triarylamine; azole; quinoxaline; oxadiazole; and benzothiadiazoles.

The co-repeat unit directly linked to the first repeat unit in the semiconducting polymer is preferably not conjugated to it. However, this is not important.

Preferably, the co-repeat unit is comprised within a conjugated segment of the semiconducting polymer. Preferably, the conjugated segment comprises no more than 4 conjugated aromatic or heteroaryl rings in that order, especially when the semiconducting polymer is intended to be used as a matrix for a phosphorescent green emitter.

For example, the semiconducting polymer may be an AB or ABB copolymer of a first repeat unit of general formula (10) and a 2, 7 linked fluorene co-repeat unit:

further, the semiconducting polymer may be an AB copolymer or an AAB copolymer having a first repeat unit of formula (14) and a 3, 6-linked carbazole co-repeat unit.

Preferred co-repeat units include 3, 6-linked fluorenes. The 3, 6-linked fluorene preferably comprises the general formula 16:

wherein R is₁And R₂Independently represent hydrogen or a substituent, such as, or optionally substituted alkyl (linear or branched), alkoxy (linear or branched), aryl, aralkyl, heteroaryl and heteroarylalkyl. More preferably, R₁And R₂At least one of which comprises optionally substituted C₄-C₂₀Alkyl or aryl.

Preferred copolymers of the invention are AB copolymers of the first repeat unit and a co-repeat unit comprising a 3, 6-linked fluorene.

Other suitable co-repeat units are carbazole, phenylene, biphenyl, and the like (see examples below):

r is alkyl or aryl

The co-repeat units in the semiconducting polymer may contain crosslinking groups to crosslink the polymer. Such co-repeat units may be derived from monomers bearing crosslinkable groups, for example monomers comprising formula 17:

wherein L and L' represent suitable reactive leaving groups; ar represents an aryl or heteroaryl group, and X represents a group containing a crosslinkable terminal group.

Suitable crosslinkable groups include styryl, cyclobutane, and oxetane. For example, X may comprise formula 47 or 48:

these are added as capping agents having reactive groups, such as halogens, boronic acids or boronic esters. For example, (47) and (48) may be derived from 4-vinylbromobenzene and 4-bromobenzocyclobutane, respectively.

Additionally or alternatively, no more than 20 wt.% of a low molecular weight crosslinking agent may be added in order to increase the crosslink density of the polymer. An example of a low molecular weight crosslinking agent is divinylbenzene.

Examples of the crosslinkable group-containing monomer include:

further examples are known to the person skilled in the art, for example from WO2005/052027 and WO 02/10129.

The HOMO level of the semiconducting polymer is preferably in the range of 4.9-5.5 electron volts, more preferably 5.0-5.2 electron volts.

The semiconductive polymer preferably contains less than 50 mole% carbazole repeat units, more preferably the semiconductive polymer is substantially free of carbazole repeat units.

Referring to the monomer of the second aspect of the invention, the monomer preferably contains two reactive leaving groups (L and L'). Reference formula (1), L and Ar₁Directly connected, and L' is preferably linked to Ar₂(if b ═ c ═ 0) or Ar₅(if c ═ 1) are directly connected.

It is to be understood that the monomer may include a first repeat unit as defined in the first aspect and a suitable reactive leaving group (L and L') attached to the end group of the first repeat unit, as shown in formula 21 below:

l-repeating unit-L' (21)

The monomer of the second aspect of the invention comprises a capping group having a reactive leaving group, as shown in formula 22:

l-repeat unit-Y (22)

Wherein L is as defined above, and Y represents an inert group, such as hydrogen.

In formulae 21 and 22, "repeating unit" represents the first repeating unit defined in the first aspect of the present invention.

The monomers may be functionalized, for example with crosslinking groups. Suitably, the crosslinkable group may be as Ar in the monomer₃And/or Ar₆The substituent on (A) exists. For example, one or two R in formulas 10-12, 14 and 15 may represent a crosslinking group in a monomer having formula 21 or 22.

Suitable crosslinking groups are known to those skilled in the art. WO2005/052027 discloses crosslinkable arylamine compounds. Preferred crosslinking groups include-CH ═ CH₂And benzocyclobutane.

In formulas 6-16 and 18-20, additional substituents other than those shown may be present.

With reference to the process of the third aspect, preferred methods of preparing the semiconductive polymers defined in the first aspect are Suzuki (Suzuki) polymerization as described, for example, in WO00/53656 And Yamamoto (Yamamoto) polymerization as described, for example, in t.yamamoto, "Electrically conductive connecting And Thermally stable pi Conjugated Poly (arylene) s Prepared by organometallic methods", advances in Polymer Science (growth in Polymer Science), 1993, 17, 1153-. These polymerization techniques all operate by means of "metal insertion" in which the metal atom of the metal complex catalyst is inserted between the aryl group and the leaving group of the monomer. In the case of Yamamoto (Yamamoto) polymerization, a nickel complex catalyst is used; in the case of Suzuki (Suzuki) polymerization, a palladium complex catalyst is used.

For example, in the preparation of linear polymers by Yamamoto (Yamamoto) polymerization synthesis, monomers having two reactive halogen groups are used. Similarly, according to the Suzuki (Suzuki) polymerisation method, at least one reactive group is a boron derivative group, such as a boronic acid or boronic ester, and the other reactive group is a halogen. Preferred halogens are chlorine, bromine and iodine, most preferably bromine.

Thus, it is to be understood that the aryl-containing repeat units and end groups shown throughout this specification can be derived from monomers bearing one or more suitable leaving groups.

Regioregular block and random copolymers can be prepared using Suzuki (Suzuki) polymerization. In particular, when one reactive group is a halogen and the other reactive group is a boron derivative group, a homopolymer or a random copolymer can be prepared. Alternatively, block or regioregular copolymers, especially AB copolymers, can be prepared when both reactive groups in the first monomer are boron and both reactive groups in the second monomer are halogen.

As an alternative to halides, other leaving groups capable of participating in metal insertion include tosylate, mesylate and triflate containing groups.

Referring to the fourth aspect of the invention, the electronic device may comprise a light emitting device.

Referring to fig. 1, the structure of the LED of the present invention comprises a transparent glass or plastic substrate 1, an anode 2, for example of indium tin oxide, and a cathode 4. A light-emitting layer 3 is provided between the anode 2 and the cathode 4.

Further layers, such as charge transport, charge injection or charge blocking layers, may be arranged between the anode 2 and the cathode 3.

In particular, it is desirable to provide a conductive hole injection layer formed of a doped organic material between the anode 2 and the light-emitting layer 3 to assist hole injection from the anode into the semiconducting polymer layer or layers. Examples of doped organic hole injection materials include poly (ethylene dioxythiophene) (PEDT), especially PEDT doped with polystyrene sulfonate (PSS) as disclosed in EP0901176 and EP0947123, and polyaniline as disclosed in US5723873 and US 5798170.

If present, the HOMO level of the hole transport layer located between the anode 2 and the light-emitting layer 3 is preferably less than or equal to 5.5 eV, and more preferably between about 4.8 and 5.5 eV.

The LUMO energy level of the electron transport layer between the light emitting layer 3 and the cathode 4, if present, is preferably about 3-3.5 electron volts.

It will be foreseen that the semiconducting polymer of the first aspect of the present invention is located within the light emitting layer or within the hole transport layer of the device. Depending on the function of the semiconducting polymer within the device. When a semiconducting polymer is used as the light emitting material, it may be located within the light emitting layer of the device, either alone or in combination with a charge transport layer. When a semiconducting polymer is used as the hole transport material, it may be located (in combination with the light emitting material) within the light emitting layer of the device, or within the hole transport layer. When a semiconducting polymer is used as a host for the light emitting dopant, particularly a phosphorescent material, it will be located in the light emitting layer of the device along with the dopant material.

When a semiconducting polymer is used as the hole transport material, the light-emitting layer 3 may consist of the light-emitting material alone or may comprise the light-emitting material in combination with one or more further materials. In particular, the luminescent material may be blended with hole and/or electron transporting materials, as disclosed in, for example, WO 99/48160. Alternatively, the light emitting material may be covalently bonded to the charge transport material.

When a semiconducting polymer is used as the hole transport material, the light emitting material may be a fluorescent or phosphorescent light emitting material. The luminescent material may comprise a polymer or a small molecule, such as a metal complex.

When semiconducting polymers are used as hole transport materials, suitable light emitting polymers for use in layer 3 are typically conjugated polymers and include poly (arylenevinylenes), such as poly (p-phenylenevinylenes), and polyarylenes, such as polyfluorenes, in particular 2, 7-linked 9, 9-dialkylpolyfluorenes or 2, 7-linked 9, 9-diarylpolyfluorenes; polyspirofluorenes, especially 2, 7-linked poly-9, 9-spirofluorene; polyindenofluorenes, especially 2, 7-linked polyindenofluorenes; polyphenylenes, especially alkyl-or alkoxy-substituted poly-1, 4-phenylenes. Such polymers are disclosed, for example, in modern materials (adv. mater.)200012(23)1737-1750 and references therein. Suitable light emitting polymers are described in further detail below for conjugated polymers.

Suitable metal complexes for use in the light-emitting layer 3 will be discussed below. It is to be understood that in embodiment (a) when the semiconductive polymer of the present invention is used as a hole transport material and embodiment (b) when the semiconductive polymer of the present invention is used as a host for a phosphorescent metal complex, the phosphorescent metal complex described below can be used in the device of the present invention. When the semiconducting polymer of the present invention is used as a hole transport material, there may be additional host materials for the phosphorescent metal complex.

A number of matrices suitable for use as additional matrix materials are disclosed in the prior art, including Ikai et al (applying the "small molecule" matrices disclosed by physical communication (appl. phys. lett., 79, No.2, 2001, 156), such as 4, 4 '-bis (carbazol-9-yl) biphenyl, known as CBP, and (4, 4' -tris (carbazol-9-yl) triphenylamine), known as TCTA); and triarylamines such as tris-4- (N-3-methylphenyl-N-phenyl) phenylamine known as MTDATA. Polymers are also referred to as matrices, in particular homopolymers such as poly (vinylcarbazole) as disclosed, for example, in applied physical communication (appl. phys. lett.)2000, 77(15), 2280; polyfluorenes described in synth.met.2001, 116,379, physical review (phys.rev.) B2001, 63, 235206 and applied physical communication (appl.phys.lett.)2003, 82(7), 1006; poly [4- (N-4-vinylbenzyloxyethyl, N-methylamino) -N- (2, 5-di-tert-butylphenyl-naphthalimide) ] in modern materials (adv.mater.)1999, 11(4), 285; and poly (p-phenylene) in journal of materials chemistry (j. mater. chem.)2003, 13, 50-55. The copolymer is also referred to as a matrix.

Suitable metal complexes include optionally substituted complexes of formula 23:

ML¹ _qL² _rL³ _s (23)

wherein M is a metal, L¹、L²And L³Each of which is a coordinating group, q is an integer; r and s are each independently 0 or an integer; and the sum of (a.q) + (b.r) + (c.s) is equal to the number of coordination sites available on M, where a is at L¹Number of coordination sites on, b is at L²The number of coordination sites on, and c is at L³Number of coordination sites on.

Heavy metal M induces strong spin-orbit coupling to allow rapid intra-system transition and release from the triplet state (phosphorescence). Suitable heavy metals M include:

lanthanoid metals, such as cerium, samarium, europium, terbium, dysprosium, thulium, erbium and niobium; and

d-block metals, especially those within rows 2 and 3, i.e. elements 39-48 and 72-80, especially ruthenium, rhodium, palladium, rhenium, osmium, iridium, platinum and gold.

Suitable ligands for the f-block metal include oxygen or nitrogen donor systems such as carboxylic acids, 1, 3-diketonates (diketonates), hydroxycarboxylic acids, schiff bases including acylphenols and iminoacyl groups. As is known, luminescent lanthanide metal complexes require a sensitizing group with a triplet excitation energy higher than the first excitation state of the metal ion. The emission comes from the f-f transition of the metal and thus the emission color is determined by the selected metal. The sharp emission is typically narrow, resulting in a pure color emission that is useful for display applications.

The d-block metal forms an organometallic complex with a carbon or nitrogen donor, such as a porphyrin or a bidentate ligand of formula 24:

wherein Ar is⁴And Ar⁵May be the same or different and is independently selected from optionally substituted aryl or heteroaryl; x¹And Y¹May be the same or different and is independently selected from carbon or nitrogen; and Ar⁴And Ar⁵May be fused together. Particularly preferred is the compound wherein X¹Is carbon and Y¹Is a ligand for nitrogen.

Examples of bidentate ligands are shown below:

Ar⁴and Ar⁵Each of which may carry one or more substituents. Particularly preferred substituents include fluoro or trifluoromethyl as disclosed in WO02/45466, WO02/44189, US2002-117662 and US2002-182441, which are useful for emission of blue-shifted complexes; alkyl or alkoxy groups disclosed in JP 2002-324679; carbazoles disclosed in WO02/81448 that can be used when used as emissive materials to assist hole transport into complexes; bromine, chlorine or iodine as disclosed in WO02/68435 and EP1245659 which may function as functional ligands for attachment of further groups; and dendrimers (dendrons) disclosed in WO02/66552 that can be used to obtain or improve the solution processability of metal complexes.

Other ligands suitable for use with the d-block elements include diketonates, especially acetylacetonate (acac), triarylphosphines, and pyridine, each of which may be substituted.

The main group metal complexes exhibit ligand-based or charge transfer emission. For these complexes, the emission color is determined by the chosen ligand as well as the metal.

The matrix material and the metal complex may be combined in a physical blend. Alternatively, the metal complex may be chemically bonded to the matrix material. In the case of a polymer matrix, the metal complex may be chemically bonded as a substituent attached to the polymer backbone, introduced as a repeat unit within the polymer backbone, or provided as a polymer end group, as disclosed in, for example, EP1245659, WO02/31896, WO03/18653, and WO 03/22908.

A wide range of fluorescent low molecular weight metal complexes are known and demonstrated in organic light emitting devices (see, e.g., macromolecule symmetry (macromol. sym.)125(1997), 1-48, US-A-5150006, US-A-6083634 and US-A-5432014), especially tris- (8-hydroxyquinoline) aluminum. Suitable ligands for divalent or trivalent metals include 8-hydroxyquinoline types (oxinoids), such as atoms that donate an oxy-nitrogen or an oxy-oxygen, ring nitrogen atoms that typically have a substituted oxygen atom, or a substituent nitrogen or oxygen atom that has a substituted oxygen atom, such as 8-hydroxyquinolate (quinolate) and hydroxyquinoxalinol-10-hydroxybenzo (h) quinolinate (quinolinato) (II), indoline (III), schiff bases, azoindoles, chromone derivatives, 3-hydroxyflavonoids, and carboxylic acids, such as salicylic acid amino carboxylic acid esters, and ester carboxylic acid esters. Optional substituents include halogen, alkyl, alkoxy, haloalkyl, cyano, amino, amido, sulfonyl, carbonyl, aryl or heteroaryl groups on the (hetero) aromatic ring which may modify the emission color.

In embodiments when the semiconducting polymer of the present invention is used as a matrix for a phosphorescent metal complex, the phosphorescent metal complex is preferably a red, green or sky blue phosphorescent material. Examples of red, green and sky-blue phosphorescent materials are:

red: irpiq (piq ═ 2-amino-1-methyl-6-phenylimidazo (4, 5-b) pyridine),

green: irppy (ppy ═ 3-phenylpyruvic acid),

sky blue: FIRpic (pic ═ 6- (difluorophosphono (phosphono) methyl) naphthalene-2-carboxylic acid) (as disclosed, for example, in US 2004/0121184).

The triplet energy level of the semiconducting polymer of the invention should be higher than the phosphorescent metal complex.

"Red phosphorescent material" refers to an organic material that emits radiation by phosphorescence in the wavelength range of 600-750 nm, preferably 600-700 nm, more preferably 610-650 nm, and most preferably with an emission peak of about 650-660 nm.

"Green phosphorescent material" refers to an organic material that emits radiation in the wavelength range of 510-580 nm, preferably 510-570 nm, by phosphorescence.

"sky-blue phosphorescent material" refers to an organic material that emits radiation in the wavelength range of 450-.

In the case of embodiments in which a semiconducting polymer is used as the matrix for the phosphorescent material, the semiconducting polymer may be blended with the phosphorescent material or may be chemically bonded thereto, for example in one of the manners described above.

The cathode 4 is selected from materials having a work function that allows electrons to be injected into the light-emitting layer. Other factors influence the choice of cathode, such as the possibility of negative interactions between the cathode and the luminescent material. The cathode may be composed of a single material, such as an aluminum layer. Alternatively, it may comprise a plurality of metals, for example a bilayer of calcium and aluminium as disclosed in WO98/10621, WO98/57381, the use of a thin layer of elemental barium as disclosed in physical communication (appl. phys. Lett.)2002, 81(4), 634 and WO02/84759, or a dielectric material to assist electron injection, for example lithium fluoride as disclosed in WO00/48258, or the use of barium fluoride as disclosed in physical communication (appl. phys. Lett.)2001, 79(5), 2001. To provide efficient injection of electrons into the device, the work function of the cathode is preferably less than 3.5 electron volts, more preferably less than 3.2 electron volts, and most preferably less than 3 electron volts.

Other light emitting devices tend to be sensitive to moisture and oxygen. Therefore, the substrate preferably has good barrier properties for preventing moisture and oxygen from entering into the device. The substrate is typically glass, however, alternative substrates may be used, particularly where flexibility of the device is desired. For example, the substrate may comprise the same plastic as in US6268695, which discloses a substrate of alternating plastics and barrier layers, or a laminate of thin glass and plastic as disclosed in EP 0949850.

The device is preferably encapsulated with an encapsulant (not shown) to prevent the ingress of moisture and oxygen. Suitable encapsulants include glass flakes, films with suitable barrier properties, alternating stacks of polymer and dielectric as disclosed in, for example, WO01/81649, or hermetic containers as disclosed in, for example, WO 01/19142. A getter material that absorbs any atmospheric moisture and/or oxygen that may permeate through the substrate or encapsulant may be disposed between the substrate and the encapsulant.

In a practical device, at least one of the electrodes is translucent so that light can be absorbed (in the case of a photo-responsive device) or emitted (in the case of an OLED). Where the anode is transparent, it typically comprises indium tin oxide. Examples of transparent cathodes are disclosed in, for example, GB 2348316.

The embodiment of figure 1 shows a device in which the device is formed by first forming an anode on a substrate, followed by deposition of a light emitting layer and a cathode, however it will be appreciated that the device of the invention may also be formed by first forming a cathode on a substrate, followed by deposition of a light emitting layer and an anode.

Conjugated polymers are commonly used in organic electronic devices. The conjugated polymer preferably comprises a repeating unit selected from the group consisting of: arylene repeat units, in particular: the 1, 4-phenylene repeat units disclosed in journal of physics (j.appl.phys.)1996, 79, 934; fluorene repeat units as disclosed in EP 0842208; indenofluorene repeat units such as disclosed in Macromolecules 2000, 33(6), 2016-; and spirofluorene repeat units as disclosed, for example, in EP 0707020. Each of these repeat units is optionally substituted. Examples of substituents include solubilizing groups, e.g. C_1-20Alkyl or alkoxy; electron withdrawing groups such as fluorine, nitro or cyano; and substituents that increase the glass transition temperature (Tg) of the polymer.

Particularly preferred conjugated polymers include optionally substituted 2, 7-linked fluorenes, most preferably repeat units of formula 25:

wherein R is¹And R²Independently selected from hydrogen, or optionally substituted alkyl, alkoxy, aryl, aralkyl, heteroaryl and heteroarylalkyl. More preferably R¹And R²At least one of which comprises optionally substituted C₄-C₂₀Alkyl or aryl.

Polymers comprising repeat units comprising optionally substituted 2, 7-linked fluorenes may provide one or more of the following functions: hole transport, electron transport and emission, depending on which layer of the device it is used on and the nature of the co-repeat unit.

In particular:

homopolymers containing repeating units of optionally substituted 2, 7-linked fluorenes, for example homopolymers of 9, 9-dialkylfluoren-2, 7-diyl, can be used to provide electron transport.

Copolymers containing optionally substituted 2, 7-linked fluorene repeat units and triarylamine repeat units, in particular selected from repeat units of the general formulae 26 to 31, are useful for providing hole transport and/or emission:

wherein X, Y, A, B, C and D are independently selected from hydrogen, or a substituent. More preferably X, Y, A, B, C and D are independently selected from optionallySubstituted branched or straight chain alkyl, aryl, perfluoroalkyl, thioalkyl, cyano, alkoxy, heteroaryl, alkaryl, and aralkyl groups. Most preferably X, Y, A and B is C_1-10An alkyl group.

Particularly preferred hole transport polymers of this type are AB copolymers containing optionally substituted 2, 7-linked fluorene repeat units and triarylamine repeat units.

Copolymers containing optionally substituted 2, 7-linked fluorene repeat units and heteroarylene repeat units are useful for charge transport or emission. Preferred heteroarylene repeat units are selected from the group consisting of formula 32-46:

wherein R is₆And R₇The same or different and are each independently hydrogen or a substituent, preferably alkyl, aryl, perfluoroalkyl, thioalkyl, cyano, alkoxy, heteroaryl, alkylaryl or arylalkyl. For ease of preparation, R is preferred₆And R₇The same is true. More preferably they are the same and each is phenyl.

The light emitting copolymer may comprise electroluminescent regions as disclosed in, for example, WO00/55927 and US6353083, and at least one of: a hole transport region and an electron transport region. If only one of the hole transporting region and the electron transporting region is provided, the electron light emitting region may also provide other hole transporting and electron transporting functions.

The different regions within this polymer may be provided along the polymer backbone according to US6353083, or as pendant groups of the polymer backbone according to WO 01/62869.

Methods of making devices of the fourth aspect of the invention are known to those skilled in the art. Typically, the polymer layer is deposited by solution processing. A single polymer or multiple polymers may be deposited from solution to form layer 5. Suitable solvents for polyarylenes, especially polyfluorenes, include monoalkylbenzenes or polyalkylbenzenes, such as toluene and xylene. Particularly preferred solution deposition techniques are spin coating, roll printing and ink jet printing.

Spin coating is particularly suitable on devices where patterning of the light emitting material is not required, such as lighting applications or simple monochrome segmented (segmented) displays.

Inkjet printing is particularly suitable for high information content displays, in particular full colour displays. Inkjet printing of OLEDs is disclosed for example in EP 0880303.

If the layers of the device are formed by solution processing, those skilled in the art will appreciate techniques to prevent intermixing of adjacent layers, for example by crosslinking one layer prior to deposition of a subsequent layer, or selecting materials for adjacent layers such that the material from which the first of the layers is formed is not soluble in the solvent used to deposit the second layer.

When the semiconducting polymer of the present invention is used as a hole transport material in a hole transport layer of a device, the layer may be crosslinked prior to deposition of the next layer of the device thereon. Alternatively, the hole transport layer may be treated by heating, for example as described in WO 2004/023573.

The synthesis of the monomers is described below. Starting material was obtained from Sigma-Aldrich.

Example 1: synthesis of monomer 1 of the invention

According to Wolfe, JP; buchwald reaction, SL; monomer 1 was prepared by a "selective" Buchwald reaction as described in journal of organic chemistry (j.org.chem.)1997, 62, 6066-one 6068.

Example 2: synthesis of monomer 2 of the invention

Step (i): "Standard" Buchwald reaction conditions: toluene, 1 mol% Pd (OAc)₂5 mol% of tris (tert-butylphenyl) phosphine, K₂CO₃And refluxing.

Step (ii): selective Buchwald reaction according to monomer example 1.

Monomer 2 is an example of a monomer containing a meta linkage at one end of the monomer, i.e., at the chemical bond with the adjacent repeat unit in the polymer chain.

Example 3: synthesis of monomer 3 of the invention

Brominating N- (4-alkylphenyl) aniline using N-bromosuccinimide (NBS) in dichloromethane to produce N- (4-bromophenyl) -N- (4-alkylphenyl) amine, which is then reacted with 1, 3-diiodobenzene according to the following scheme:

in Goodbrand, HB; hu, N-X; the conditions for the Ullmann reaction are disclosed in journal of organic chemistry (J.org.chem.)1999, 64, 670-.

This is an example of a monomer containing an internal meta linkage, i.e., a monomer present as a repeat unit within the polymer, if present, will provide a meta linkage along the polymer backbone, such meta linkage being disposed away from the terminus of the repeat unit.

Example 4: synthesis of monomer 4 of the invention

The central biphenyl unit in monomer 4 may be substituted in 2, 2 'or 3, 3' bits, increasing the torque and thus further reducing the conjugation.

Example 5: synthesis of monomer 5 of the present invention

Steps (i) and (iii): standard Buchwald reaction conditions.

Step (ii): NBS bromination in dichloromethane was used.

Example 6: synthesis of monomer 6 of the invention

3, 3' -dibromobiphenyl was prepared according to the procedure described in Demir, AS, Reis, O, Erulllahoglu, M, J.Org.Chem.) -2003, 62, 10130-:

step (i): standard Buchwald reaction conditions.

Step (ii): selective Buchwald reaction conditions.

Example 7: synthesis of monomer 7 of the invention

The conditions for the Ullmann reaction are the same as above.

Example 8: synthesis of monomer 8 of the invention

According to Blatter, K; schlueter, A-D; 3, 6-dibromo naphthalene was prepared by the method described in Synthesis (Synthesis)1989, 5, 356 and reacted according to the following scheme:

step (i): standard Buchwald reaction conditions.

Step (ii): selective Buchwald reaction conditions.

Example 9: synthesis of monomer 9 of the invention

Synthesis of starting materials: see example 6.

Step (i): standard Buchwald reaction conditions.

Step (ii): selective Buchwald reaction conditions.

Examples 10 to 18: synthesis of polymers 1 to 9 of the invention

Copolymers 1-9 were formed by Suzuki (Suzuki) polymerisation of fluorene units and repeat units derived from monomers 1-9 according to the method outlined in WO 00/53656.

Example 19: use as hole transport material in LEDs

Indium tin oxide anodes (available from Applied Films) supported on glass substratesSi, USA, Colorado (Colorado, USA)), by spin coating, deposition toPoly (ethylene dioxythiophene)/poly (styrene sulfonate) (PEDT/PSS) available from hc Starck, lewakusen, germany. A hole transport layer of polymer 1 was deposited by spin coating a xylene solution onto the PEDT/PSS layer to a thickness of about 10 nm and heated at 180 ℃ for 1 hour. The emissive material was deposited by spin coating a xylene solution onto the polymer 1 coating to a thickness of about 65 nm. A Ba/Al cathode is formed on the emissive layer by evaporating a first layer of barium to a thickness of up to about 10 nanometers, and a second layer of aluminum barium to a thickness of about 100 nanometers on a semiconducting polymer. Finally, the device is sealed using a metal enclosure containing a getter placed on the device and glued to the substrate, so as to form a hermetic seal.

In the case of a fluorescent emission layer, red, green and/or blue electroluminescent materials containing fluorene repeat units as described in WO00/46321 may be used.

In the case of a phosphorescent emissive layer, a blend of host materials disclosed in WO02/066552, such as a complex of CBP (4, 4' -bis (carbazol-9-yl) biphenyl) and iridium, such as the dendritic complex 47 shown below, may suitably be used as the phosphorescent emissive layer.

Example 20: use as a matrix in green LEDs

On an indium tin oxide anode (available from Applied Films, Colorado, USA) supported on a glass substrate, deposited by spin coating from a xylene solution as a BaytronPoly (ethylene dioxythiophene)/poly (styrene sulfonate) (PEDT/P) from H C Starck, Lewakusen, GermanySS) to a thickness of about 10 nm and heated at 180 c for 1 hour. A solution of hole transport polymer 1 was deposited by spin coating a xylene solution onto the PEDT/PSS layer to a thickness of about 10 nm and heated at 180 ℃ for 1 hour. The polymer 2 of the invention is brought together with the solution of the dendritic metal complex 47 to a thickness of about 65 nm by spin coating a xylene solution on the PEDT/PSS layer. A Ba/Al cathode was formed thereon by first evaporating a first layer of barium to a thickness of up to about 10 nm, and a second layer of aluminum barium to a thickness of about 100 nm. Finally, the device is sealed using a metal enclosure containing a getter placed on the device and glued to the substrate, so as to form a hermetic seal.

Claims (33)

1. A semiconductive polymer comprising a first repeat unit comprising formula 1 in the polymer backbone:

wherein a is 1 or 2; b is 0 or 1; and c is 0, 1 or 2, with the proviso that if c is 0, then b is 0; ar (Ar)₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆Each independently represents an aromatic or heteroaromatic ring, orFused derivatives thereof; characterized in that Ar is₁、Ar₂、Ar₄And Ar₅Is non-conjugated; and with the proviso that (a) when a is 1, then Ar₁Not by direct chemical bond to Ar₂And (b) when b is 1 and c is 1, then Ar₄Not by direct chemical bond to Ar₅And (c) when b is 0 and c is 1, then Ar₂Not by direct chemical bond to Ar₅And (d) when a is 2, then Ar₁The radicals are not linked by a single bond, and (e) if c is 2, then Ar₅The groups are not connected by single bonds.

2. The polymer of claim 1, wherein the first repeat unit comprises one of the following formulas 3-5:

wherein Ar is₁-Ar₆Each as defined in claim 1; represents a direct chemical bond, X represents a bridging group or a bridging atom; and d is 0 or 1, where there are-X-and- (X) as shown_d-one or a combination of linking groups.

3. The polymer of claim 1 or 2, wherein Ar₃And/or Ar₆Having at least one substituent.

4. The polymer of any one of claims 1 to 3, wherein Ar₃And/or Ar₆Represents a phenyl group.

5. The polymer of claim 4, wherein Ar₃And/or Ar₆Represents a phenyl group and has at least one substituent at the para position.

6. A polymer according to any preceding claim, wherein Ar is₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆Each comprising a phenyl group.

7. A polymer according to any preceding claim, wherein the two Ar end groups in the first repeat unit are non-conjugated.

8. The polymer of claim 7, wherein the two Ar end groups in the first repeat unit independently represent meta-attached phenyl groups.

9. The polymer of claim 8, wherein the first repeat unit comprises formula 10, 11, or 12:

wherein R represents hydrogen or a substituent; - - -represents a direct chemical bond; x represents a bridging group or a bridging atom; and in general formula 10- - (X)_dThe linking group is optional.

10. The polymer of any one of claims 1-6, wherein if c is 1 or 2, then Ar is₂And Ar₄One or both of which are non-conjugated.

11. The polymer of claim 10, wherein Ar₂And Ar₄One or two of which independently represent a meta-attached phenyl group.

12. The polymer of claim 11, wherein if c-1 and b-0, then Ar is₂Represents a meta-attached phenyl group.

13. The polymer of claim 12, wherein the first repeat unit comprises formula 14:

wherein- - -represents a direct chemical bond; each X independently represents a bridging group or a bridging atom; c is 0 or 1; each R independently represents a substituent and- - (X)_cThe linking group is independently optional.

14. The polymer of claim 10, wherein if c-1 and b-0, then Ar is₂Represents a fused derivative of a benzene ring which is fused in the meta position.

15. The polymer of claim 14, wherein the fused derivative comprises a group having formula 8 or 9:

16. the polymer of claim 15, wherein the first repeat unit comprises formula 15:

wherein- - -represents a direct chemical bond; each X independently represents a bridging group or a bridging atom; c is 0 or 1; each R independently represents a substituent and- - (X)_cThe linking group is independently optional.

17. A polymer according to any preceding claim, wherein the first repeat unit is functionalised such that the semiconductive polymer is crosslinked.

18. A polymer according to any preceding claim, wherein the semi-conducting polymer is substantially non-conjugated.

19. A polymer as claimed in any preceding claim wherein the HOMO level of the semiconducting polymer is in the range 5.0 to 5.2 electron volts.

20. A polymer as claimed in any preceding claim wherein the semiconductive polymer comprises a homopolymer.

21. A polymer according to any of claims 1 to 19, wherein the semi-conducting polymer comprises a copolymer or higher order polymer.

22. The polymer of claim 21, wherein the polymer comprises co-repeat units comprising a 3, 6-linked fluorene.

23. Use of a semiconducting polymer as defined in any of claims 1 to 22 for transporting holes in an organic electronic device or as a matrix for a phosphorescent metal complex.

24. A monomer for preparing a semiconducting polymer according to any of claims 1 to 22, said monomer comprising formula 1:

wherein a, b, c, Ar₁、Ar₂、Ar₃、Ar₄、Ar₅And Ar₆As defined in any one of claims 1 to 17; and the leaving groups L and L' are capable of participating in the polymerization.

25. The monomer of claim 24, comprising formula 21 or 22:

l-repeating unit-L' (21)

L-repeat unit-Y (22)

Wherein L and L¹As defined in claim 24; y represents an inert group; and "repeat unit" denotes a first repeat unit as defined in any one of claims 1 to 17.

26. A method of preparing a semiconducting polymer according to any of claims 1 to 22, comprising the step of polymerising a plurality of monomers according to claim 24 or 25 under conditions to form the semiconducting polymer.

27. An organic electronic device comprising a semiconducting polymer as defined in any of claims 1 to 22.

28. An electronic device according to claim 27 wherein the device comprises a light-emitting device comprising a substrate, an anode, a cathode, a light-emitting layer between the anode and the cathode and optionally a hole-transporting layer between the anode and the light-emitting layer, wherein the semiconducting polymer as defined in any of claims 1 to 22 is located in the light-emitting layer or the hole-transporting layer.

29. The device of claim 28 wherein the light emitting layer comprises a semiconducting polymer as defined in any of claims 1 to 22 and a phosphorescent metal complex.

30. The device of claim 29, wherein the phosphorescent metal complex is a red or green phosphorescent material.

31. A method of manufacturing an electronic device as defined in any of claims 27 to 30, said method comprising the step of depositing a solution comprising a semiconducting polymer as defined in any of claims 1 to 22 to form a layer by solution processing.

32. The method of claim 31, wherein the layer formed is a hole transport layer, and the method further comprises the step of crosslinking the hole transport layer prior to depositing the next layer of the device thereon.

33. The method of claim 31, wherein the layer formed is a hole transport layer, and the method further comprises the step of heat treating the hole transport layer prior to depositing a next layer of the device thereon.