ORGANIC SEMICONDUCTOR COMPOSITIONS

Abstract

The present invention relates to organic semiconductor compositions and organic semiconductor layers and devices comprising such organic semiconductor compositions. The invention is also concerned with methods of preparing such organic semiconductor compositions and layers and uses thereof. The invention has application particularly in the field of displays such as organic field effect transistors (OFETS), integrated circuits, organic light emitting diodes (OLEDS), photodetectors, organic photovoltaic (OPV) cells, sensors, lasers, memory elements and logic circuits.

Claims

1. An organic semiconductor composition comprising a polyacene compound and an organic binder, wherein said polyacene compound is selected from those of Formulae (4) and (5): ##STR00029## wherein R.sup.25, R.sup.26 and R.sup.27 are independently selected from the group consisting of methyl, ethyl and isopropyl; and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.8, R.sup.9, R.sup.10 and R.sup.11 are independently selected from the group consisting of C.sub.1-C.sub.6 alkyl, C.sub.1-C.sub.6 alkoxy and C.sub.6-C.sub.20 aryloxy, and wherein said organic binder is a semiconducting binder comprising a unit of Formula (6): ##STR00030## wherein Ar.sub.1, Ar.sub.2 and Ar.sub.3, which may be the same or different, each represent, independently if in different repeat units, an optionally substituted C.sub.6-40 aromatic group (mononuclear or polynuclear), wherein at least one of Ar.sub.1, Ar.sub.2 and Ar.sub.3 is substituted with at least one polar or more polarizing group, and n=1 to 20, and said organic binder has a permittivity at 1000 Hz of between 3.4 and 8.0, with the proviso that the composition is not a composition containing components (a) and (b), wherein (a) is a 2,4-dimethoxy polytriarylamine polymer having a Mn of 3471 g/mol, in which n is 11.5, said polymer having a dielectric constant of 3.9 and a polydispersity of 2.6; and wherein (b) is 1,4,8,11-tetramethyl bis-triethylsilvylethynvylpentacene; wherein (a) and (b) are in a ratio of 2:1 in bromobenzene at 2% by weight total solids content.

2. The composition according claim 1, wherein said binder has a permittivity at 1000 Hz of between 4.0 and 6.0.

3. The composition according claim 1, wherein said binder has a permittivity at 1000 Hz of between 3.4 and 4.5.

4-16. (canceled)

17. The composition according to claim 1, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.8, R.sup.9, R.sup.10 and R.sup.11 are independently selected from methyl, ethyl, propyl, n-butyl, isobutyl, t-butyl, methoxy, ethoxy, propyloxy and butyloxy groups.

18. The composition according to claim 1, wherein R.sup.1, R.sup.4, R.sup.8 and R.sup.11 are the same and are methyl or methoxy groups and R.sup.25, R.sup.26 and R.sup.27 are the same and are ethyl or isopropyl groups.

19. The composition according to claim 18, wherein R.sup.1, R.sup.4, R.sup.8 and R.sup.11 are methyl groups and R.sup.25, R.sup.26 and R.sup.27 are ethyl groups.

20. The composition according to claim 18, wherein R.sup.1, R.sup.4, R.sup.8 and R.sup.11 are methyl groups and R.sup.25, R.sup.26 and R.sup.27 are isopropyl groups.

21. The composition according to claim 18, wherein R.sup.1, R.sup.4, R.sup.8 and R.sup.11 are methoxy groups and R.sup.25, R.sup.26 and R.sup.27 are ethyl groups.

22. The composition according to claim 18, wherein R.sup.1, R.sup.4, R.sup.8 and R.sup.11 are methoxy groups and R.sup.25, R.sup.26 and R.sup.27 are isopropyl groups.

23. The composition according to 1, wherein R.sup.2, R.sup.3, R.sup.9 and R.sup.10 are the same and are methyl or methoxy groups and R.sup.25, R.sup.26 and R.sup.27 are the same and are ethyl or isopropyl groups.

24. The composition according to claim 23, wherein R.sup.2, R.sup.3, R.sup.9 and R.sup.10 are methyl groups and R.sup.25, R.sup.26 and R.sup.27 are ethyl groups.

25. The composition according to claim 23, wherein R.sup.2, R.sup.3, R.sup.9 and R.sup.10 are methyl groups and R.sup.25, R.sup.26 and R.sup.27 are isopropyl groups.

26. The composition according to claim 23, wherein R.sup.2, R.sup.3, R.sup.9 and R.sup.10 are methoxy groups and R.sup.25, R.sup.26 and R.sup.27 are ethyl groups.

27. The composition according to claim 23, wherein R.sup.2, R.sup.3, R.sup.9 and R.sup.10 are methoxy groups and R.sup.25, R.sup.26 and R.sup.27 are isopropyl groups.

28-29. (canceled)

30. The composition according to claim 1, wherein said one or more polar or polarising group(s) on the organic binder is independently selected from the group consisting of nitro group, nitrile group, C.sub.1-40 alkyl group substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C.sub.1-40 alkoxy group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C.sub.1-40 carboxylic acid group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; C.sub.2-40 carboxylic acid ester optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; sulfonic acid optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; sulfonic acid ester optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; cyanate group, isocyanate group, thiocyanate group, thioisocyanate group; and an amino group optionally substituted with a nitro group, a nitrile group, a cyanate group, an isocyanate group, a thiocyanate group or a thioisocyanate group; and combinations thereof.

31. The composition according to claim 1, wherein said one or more polar or polarising group(s) is independently is selected from the group consisting of C.sub.1-4 cyanoalkyl group, C.sub.1-10 alkoxy group, nitrile group, amino group and combinations thereof.

32. The composition according to claim 1, wherein the polar or polarizing group is selected from the group consisting of methoxy, ethoxy, propoxy, butoxy, cyanomethyl, cyanoethyl, nitrile, NH.sub.2 and combinations thereof.

33. The composition according to any of claim 1, wherein Ar.sub.1, Ar.sub.2 and Ar.sub.3, are independently selected from the group consisting of C.sub.6-10 aryl, C.sub.7-12 aralkyl and C.sub.7-12 alkaryl, any of which may be substituted with 1, 2, or 3 groups independently selected from C.sub.1-2 alkoxy, C.sub.1-3 cyanoalkyl, CN and mixtures thereof, and n=1 to 10.

34. The composition according to any of claim 1, wherein Ar.sub.1, Ar.sub.2 and Ar.sub.3 are all phenyl which may be independently substituted with 1 or 2 groups selected from methoxy, cyanomethyl and CN and mixtures thereof, and n=1 to 10.

35. (canceled)

36. The composition according to claim 1, wherein said organic binder comprises at least one unit selected from the following structures (G) to (J): ##STR00031##

37-40. (canceled)

41. The composition according to claim 1, wherein said composition has a charge mobility value of at least 0.5 cm V.sup.1 s.sup.1.

42. The composition according to claim 41, wherein said composition has a charge mobility value of between 1.5 and 8.0 cm V.sup.1 s.sup.1.

43-45. (canceled)

46. A method of forming the organic semiconductor layer according to claim 1, comprising the steps of: a. Mixing the organic semiconductor composition according to the present invention with a solvent to form a semiconductor layer formulation; b. Depositing said formulation onto a substrate; and c. Optionally removing the solvent to form an organic semiconductor layer.

47-51. (canceled)

52. An electronic device comprising the organic semiconductor composition or layer according to any of claim 1.

53. The electronic device according to claim 52, wherein said device is selected from the group consisting of organic field effect transistors (OFETS), integrated circuits, organic light emitting diodes (OLEDS), photodetectors, organic photovoltaic (OPV) cells, sensors, lasers, memory elements and logic circuits.

54. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0113] FIG. 1 is a representation of top contact/bottom gate

[0114] FIG. 2 is a representation of bottom contact/bottom gate

[0115] FIG. 3 is a representation of top contact/top gate

[0116] FIG. 4 is a representation of bottom contact/top gate

[0117] LabelsA: Substrate; B: Gate electrode; C: Dielectric layer; D: Semiconductor layer; E: Source electrode; F: Gate electrode

DETAILED DESCRIPTION OF THE INVENTION

General

[0118] The term about in relation to a numerical value x means, for example, x+10%.

[0119] The word substantially does not exclude completely e.g. a composition which is substantially free from Y may be completely free from Y. Where necessary, the word substantially may be omitted from the definition of the invention.

[0120] Molecular weight of a polymeric material (including monomeric or macromeric materials), as used herein, refers to the number-average molecular weight unless otherwise specifically noted or unless testing conditions indicate otherwise.

[0121] A polymer means a material formed by polymerising and/or crosslinking one or more monomers, macromers and/or oligomers and having two or more repeat units.

[0122] A semiconducting binder as used herein refers to an organic binder that is between a conductor and an insulator in its ability to conduct electrical current.

[0123] Preferably, according to the present invention, a semiconducting material, composition or layer is one which has an electrical conductivity in the range of 10.sup.3 to 10.sup.8 siemens per centimetre, more preferably between 500 to 10.sup.7, more preferably between 300 to 10.sup.6, more preferably between 250 to 10.sup.5, more preferably between 10 to 10.sup.5 siemens per centimetre, more preferably greater than 10.sup.4 or 10.sup.3 siemens per centimetre. The conductivity of the material or composition is measured according to ASTM D4308-10. The same test may be used to measure the conductivity of the compositions, layers and polyacene compounds of the present invention.

[0124] As used herein, the term alkyl group refers to a straight or branched saturated monovalent hydrocarbon radical, having the number of carbon atoms as indicated. By way of non limiting example, suitable alkyl groups include, methyl, ethyl, propyl, n-butyl, t-butyl, iso-butyl and dodecanyl.

[0125] As used herein, the term alkoxy group include without limitation, methoxy, ethoxy, 2-methoxyethoxy, t-butoxy, etc.

[0126] As used herein, the term amino group includes, without limitation, dimethylamino, methylamino, methylphenylamino, phenylamino, etc.

[0127] The term carbyl refers to any monovalent or multivalent organic radical moiety which comprises at least one carbon atom other without any non-carbon atoms (CC), or optionally combined with at least one non-carbon atoms such as N, O, S, P, SI, Se, As, Te or Ge (for example carbonyl etc.).

[0128] The term hydrocarbon group denotes a carbyl group that additionally contains one or more H atoms and optionally contains one or more hetero atoms.

[0129] A carbyl or hydrocarbyl group comprising 3 or more carbon atoms may be linear, branched and/or cyclic, including spiro and/or fused rings.

[0130] Preferred carbyl or hydrocarbyl groups include alkyl, alkoxy, alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyloxy, each of which is optionally substituted and has 1 to 40, preferably 1 to 18 carbon atoms, furthermore optionally substituted aryl, aryl derivative or aryloxy having 6 to 40, preferably 6 to 18 carbon atoms, furthermore alkylaryloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy, each or which is optionally substituted and has 7 to 40, more preferable 7 to 25 carbon atoms.

[0131] The carbyl or hydrocarbyl group may be saturated or unsaturated acyclic group, or a saturated or unsaturated cyclic group. Unsaturated acyclic or cyclic groups are preferred, especially alkenyl and alkynyl groups (especially ethynyl).

[0132] In the polyacenes of the present invention, the optional substituents on the said C.sub.1-C.sub.40 carbyl or hydrocarbyl groups for R.sub.1-R.sub.14 etc. preferably are selected from: silyl, sulpho, sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro, halo, C.sub.1-4 alkyl, C.sub.6-12 aryl, C.sub.1-4 alkoxy, hydroxy and/or all chemically possible combinations thereof. More preferable among these optional substituents are silyl and C.sub.6-12 aryl and most preferable is silyl.

[0133] Substituted alkyl group refers to an alkyl group having one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms other than carbon and hydrogen either alone (e.g., a halogen such as F) or in combination with carbon (e.g., a cyano group) and/or hydrogen atoms (e.g., a hydroxyl group or a carboxylic acid group).

[0134] Alkenyl group refers to a monovalent group that is a radical of an alkene, which is a hydrocarbon with at least one carbon-carbon double bond. The alkenyl can be linear, branched, cyclic, or combinations thereof and typically contains 2 to 30 carbon atoms. In some embodiments, the alkenyl contains 2 to 20, 2 to 14, 2 to 10, 4 to 10, 4 to 8, 2 to 8, 2 to 6, or 2 to 4 carbon atoms. Exemplary alkenyl groups include, but are not limited to, ethenyl, propenyl, and butenyl.

[0135] Substituted alkenyl group refers to an alkenyl group having (i) one or more CC double bonds, and (ii) one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms other than carbon and hydrogen either alone (e.g., a halogen such as F) or in combination with carbon (e.g., a cyano group) and/or hydrogen atoms (e.g., a hydroxyl group or a carboxylic acid group).

[0136] Alkynyl group refers to a monovalent group that is a radical of an alkyne, a hydrocarbon with at least one carbon-carbon triple bond. The alkynyl can be linear, branched, cyclic, or combinations thereof and typically contains 2 to 30 carbon atoms. In some embodiments, the alkynyl contains 2 to 20, 2 to 14, 2 to 10, 4 to 10, 4 to 8, 2 to 8, 2 to 6, or 2 to 4 carbon atoms. Exemplary alkynyl groups include, but are not limited to, ethynyl, propynyl, and butynyl.

[0137] Substituted alkynyl group refers to an alkynyl group having (i) one or more CC triple bonds, and (ii) one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms other than carbon and hydrogen either alone (e.g., a halogen such as F) or in combination with carbon (e.g., a cyano group) and/or hydrogen atoms (e.g., a hydroxyl group or a carboxylic acid group or a silyl group).

[0138] Cycloalkyl group refers to a monovalent group that is a radical of a ring structure consisting of 3 or more carbon atoms in the ring structure (i.e., only carbon atoms in the ring structure and one of the carbon atoms of the ring structure is the radical).

[0139] Substituted cycloalkyl group refers to a cycloalkyl group having one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms (e.g., a halogen such as F, an alkyl group, a cyano group, a hydroxyl group, or a carboxylic acid group).

[0140] Cycloalkylalkylene group refers to a monovalent group that is a ring structure consisting of 3 or more carbon atoms in the ring structure (i.e., only carbon atoms in the ring), wherein the ring structure is attached to an acyclic alkyl group (typically, from 1 to 3 carbon atoms, more typically, 1 carbon atom) and one of the carbon atoms of the acyclic alkyl group is the radical. Substituted cycloalkylalkylene group refers to a cycloalkylalkylene group having one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms (e.g., a halogen such as F, an alkyl group, a cyano group, a hydroxyl group, or a carboxylic acid group).

[0141] Aryl group refers to a monovalent group that is a radical of an aromatic carbocyclic compound. The aryl can have one aromatic ring or can include up to 5 carbocyclic ring structures that are connected to or fused to the aromatic ring. The other ring structures can be aromatic, non-aromatic, or combinations thereof. Examples of preferred aryl groups include, but are not limited to, phenyl, 2-tolyl, 3-tolyl, 4-tolyl, biphenyl, 4-phenoxyphenyl, 4-fluorophenyl, 3-carbomethoxyphenyl, 4-carbomethoxyphenyl, terphenyl, anthryl, naphthyl, acenaphthyl, anthraquinonyl, phenanthryl, anthracenyl, pyrenyl, perylenyl, and fluorenyl.

[0142] Substituted aryl group refers to an aryl group having one or more substituents on the ring structure, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms (e.g., a halogen such as F, an alkyl group, a cyano group, a hydroxyl group, or a carboxylic acid group).

[0143] Arylalkylene group refers to a monovalent group that is an aromatic ring structure consisting of 6 to 10 carbon atoms in the ring structure (i.e., only carbon atoms in the ring structure), wherein the aromatic ring structure is attached to an acyclic alkyl group having one or more carbon atoms (typically, from 1 to 3 carbon atoms, more typically, 1 carbon atom) and one of the carbons of the acyclic alkyl group is the radical.

[0144] Substituted arylalkylene group refers to an arylalkylene group having one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms (e.g., a halogen such as F, an alkyl group, a cyano group, a hydroxyl group, or a carboxylic acid group).

[0145] Acetyl group refers to a monovalent radical having the formula C(O)CH.sub.3.

[0146] Heterocyclic ring refers to a saturated, partially saturated, or unsaturated ring structure comprising at least one of O, N, S and Se in the ring structure.

[0147] Substituted heterocyclic ring refers to a heterocyclic ring having one or more substituents bonded to one or more members of the ring structure, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms (e.g., a halogen such as F, an alkyl group, a cyano group, a hydroxyl group, or a carboxylic acid group).

[0148] Carbocyclic ring refers to a saturated, partially saturated, or unsaturated ring structure comprising only carbon in the ring structure.

[0149] Substituted carbocyclic ring refers to a carbocyclic ring having one or more substituents bonded to one or more members of the ring structure, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms (e.g., a halogen such as F, an alkyl group, a cyano group, a hydroxyl group, or a carboxylic acid group).

[0150] Ether group refers to a R.sub.aOR.sub.b radical wherein R.sub.a is a branched or unbranched alkylene, arylene, alkylarylene or arylalkylene hydrocarbon and R.sub.b is a branched or unbranched alkyl, aryl, alkylaryl or arylalkyl hydrocarbon.

[0151] Substituted ether group refers to an ether group having one or more substituents thereon, wherein each of the one or more substituents comprises a monovalent moiety containing one or more atoms other than carbon and hydrogen either alone (e.g., a halogen such as F) or in combination with carbon (e.g., a cyano group) and/or hydrogen atoms (e.g., a hydroxyl group or a carboxylic acid group).

[0152] Unless otherwise defined, a substituent or optional substituent is preferably selected from the group consisting of halo (I, Br, Cl, F), CN, NO.sub.2, NH.sub.2, COOH and OH.

EXAMPLES OF THE PRESENT INVENTION

[0153] The following examples of the present invention are merely exemplary and should not be viewed as limiting the scope of the invention.

[0154] Measurement of the Capacitance of the Polymer Binder

[0155] The polymer binder was diluted with tetralin in order to lower its viscosity and make it possible to obtain a film thickness of 1 micron when spin coated for the spin speed range 1000-2000 rpm/s. The polymer binder solution was spin coated at 500 rpm for 10 seconds, followed by 1500 rpm for 30 seconds, onto ITO coated and cleaned 11 inch glass substrates.

[0156] To clean the ITO coated substrates they were submerged in a 3% solution of DECon 90 and put in an ultrasonic bath (water temperature >65 C.), washed with deionised water, submerged in deionised water and put in an ultrasonic bath (water temperature >65 C.), washed a further time with deionised water, submerged in isopropyl alcohol and then put in an ultrasonic bath (water temperature >65 C.), and then spin dried.

[0157] After deposition of the polymer binder the substrate was annealed on a hotplate at 120 C. for 5 minutes.

[0158] The substrate was then covered with a capacitance shadow mask, and top electrodes were deposited by evaporation of gold using a thermal deposition method. In order to determine the exact thickness of the polymer binder layer, the thickness was measured using a Dektak 3030 profilometer (available from Veeco, Plainview N.Y.) at three different positions and averaged; these values were subsequently used to calculate the dielectric constants of the polymer binders.

[0159] Capacitance measurements were then carried out using impedance analyser Agilent 43961A and a probe station. In order to improve the electrical contact between the ITO back electrode and the external probe electrode, a conductive silver paste was applied. The sample being measured was placed in a metal box on the metal plate to ensure minimum influence from the external environment.

[0160] Before each set of measurements was obtained, the analyser was calibrated using the 43961A Impedance Test Kit as a compensation routine was carried out to account for internal capacitance of the analyser and test fixture. The measurement calibration was carried out with open and shorted circuit; the dielectric constant was calculated using the following equation:

C=.sub.o(A/d).

[0161] Wherein C is the capacitance (Farads), A is the area (m.sup.2), d is the coating thickness (m), is the dielectric constant (permittivity), and .sub.o is the permittivity of free space and is taken as 8.885410.sup.12 F/m.

[0162] As a reference sample, a polystyrene sample (Mw350,000) having a thickness of 1 m was tested. The measured and calculated dielectric constant of the polystyrene reference was =2.55 at 10,000 Hz, which is in good agreement with the reported value (2.5), refer to J. R. Wunsch, Polystyrene-Synthesis, Production and Applications, Rapra Review Reports, 2000, Volume 10, No. 4, page 32.

[0163] OTFT Fabrication Method

[0164] A substrate (either glass or a polymer substrate such as PEN) is patterned with Au source drain electrodes either by a process of thermal evaporation through a shadow mask or by photolithography (an adhesion layer of either Cr or Ti is deposited on the substrate prior to deposition of Au). The Au electrodes can then optionally be cleaned using an O.sub.2 plasma cleaning process. A solution of organic semiconductor in binder is then applied by spin coating (the sample is flooded with the solution and the substrate is then spun at 500 rpm for 5 seconds then 1500 rpm for 1 minute). The coated substrate is then dried in air on a hot stage. The dielectric material, for example 3 wt % PTFE-AF 1600 (Sigma-Aldrich cat #469610) dissolved in FC-43 was then applied to the substrate by spin coating (sample flooded then spun at 500 rpm for 5 seconds then 1500 rpm for 30 seconds). The substrate was then dried in air on a hot stage (100 C. for 1 minute). A gate electrode (Au) is then defined over the channel area by evaporation through a shadow mask.

[0165] The mobility of the OTFT for the binders is characterised by placing on a manual probe station connected to a Keithley SCS 4200 semiconductor analyzer. The source drain voltage (V.sub.DS) is set at 2V (linear) or 40V (saturation) and the gate voltage (V.sub.G) scanned from +20V to 60V. Drain current is measured and mobility calculated from the transconductance.

[0166] The mobility of the OTFT for the formulations is characterised by placing on a semi-auto probe station connected to a Keithley SCS 4200 semiconductor analyzer. The source drain voltage (V.sub.DS) is set at 2V and the gate voltage (V.sub.G) scanned from +20V to 40V. Drain current is measured and mobility calculated from the transconductance.

[0167] In linear regime, when |V.sub.G|>|V.sub.DS|, the source-drain current varies linearly with V.sub.G. Thus the field effect mobility () can be calculated from the gradient (S) of I.sub.DS vs. V.sub.G given by equation 1 (where C.sub.i is the capacitance per unit area, W is the channel width and L is the channel length):

[00002]$\begin{array}{cc}S=\frac{.Math..Math.{\mathrm{WC}}_i.Math.V_{\mathrm{DS}}}{L}& \mathrm{Equation}.Math..Math.1\end{array}$

[0168] In the saturation regime, the mobility is determined by finding the slope of I.sub.DS.sup.1/2 vs. V.sub.G and solving for the mobility (Equation 2)

[00003]$\begin{array}{cc}{I}_{\mathrm{DS}}\frac{{\mathrm{WC}}_i.Math.{\left(V_{\mathrm{GS}}-V_T\right)}^2}{2.Math.L}& \mathrm{Equation}.Math..Math.2\end{array}$

[0169] Method to Determine Molecular Weight and Molecular Weight Distribution

[0170] Gel Permeation Chromatography (GPC) analysis was carried out on a Waters Alliance 2695 instrument along with a Waters 2414 refractive index (RI) detector, using an Agilent PL gel 5 m Mixed-D 3007.5 mm column eluting with tetrahydrofuran. Calibration was performed using Agilent EasiVial polystyrene standards (PL2010-0400)

EXAMPLES

1. Preparation of bis(N-4-chlorophenyl)-2-methoxyphenylamine (Compound 1)

[0171] ##STR00010##

[0172] A mixture of 2-methoxyaniline (Sigma-Aldrich A88182, 20.0 g, 162 mmol, 1 equiv), 1-chloro-4-iodobenzene (96.8 g, 406 mmol, 2.5 equiv), copper powder (31.0 g, 488 mmol, 3.0 equiv), potassium carbonate (80.8 g, 585 mmol, 3.6 equiv), 18-crown-6 (10.7 g, 0.25 equiv, 40.6 mmol) and o-dichlorobenzene (40 mL) were charged to a nitrogen purged 500 mL round bottom flask fitted with a Dean-Stark apparatus (including a condenser) and a thermometer. The reaction mixture was heated to 190 C. with stirring. The reaction was monitored by thin-layer chromatography (consumption of the aniline/appearance of product). When the reaction as complete (48 hrs), the mixture was allowed to cool to room temperature. The mixture was then filtered through a Whatman GF/F filter to remove inorganic solids. The filter cake was washed with dichloromethane (200 mL). The filtrate was then added to a separating funnel containing water (100 mL). The mixture was then agitated and the organic and aqueous layers separated. The organic layer was died over MgSO.sub.4, filtered and concentrated to give a dark brown viscous oil. The mixture was then purified by flash column chromatography (gradient elution: 20%-50% dichloromethane in heptane) to give an off-white solid. Recrystallisation from methanol gave the product as a colourless solid (25.1 g, 73.0 mmol, 45%). .sup.1H NMR (500 MHz, CDCl.sub.3) 7.37-7.00 (12H, m, aromatic), 3.79 (3H, s, OCH.sub.3).

2. Preparation of High Molecular Weight Binder (Oligomer 1)

[0173] ##STR00011##

[0174] A flame dried 500 mL round-bottom flask fitted with a condenser, thermometer and nitrogen inlet was charged with nickel (11) chloride (0.20 g, 1.54 mmol), zinc powder (10.80 g, 165 mmol), 2,2-bipyridyl (0.35 g, 2.24 mmol), triphenylphosphine (7.80 g, 29.7 mmol) and anhydrous N,N-dimethylacetamide (200 mL). The mixture was heated to 70 C., at which point the reaction mixture becomes dark brown/red in colour (characteristic of the formation of a nickel (0) species). The mixture was stirred at 70 C. for a further 30 minutes. Bis(N-4-chlorophenyl)-2-methoxyphenylamine (Compound 1, 20.0 g, 58.1 mmol) was then added in a single charge. After approx. 90 minutes solid material began to precipitate from the reaction mixture. Toluene (70 mL) and another charge of nickel (II) chloride (0.2 g, 1.54 mmol) were added and the reaction mixture was stirred at 70 C. overnight. 0.10 The reaction mixture was allowed to cool and was then filtered through a Whatman Grade 1 filter paper. The filtered solid was then dissolved in toluene (100 mL). Concentrated hydrochloric acid was then added dropwise to destroy excess zinc. The phases were then separated and the organic phase concentrated to give a pale yellow semisolid. This was dissolved in THF (100 mL) and poured into MeOH (100 mL). The precipitated solid was collected by filtration and dried (16.1 g, n.sub.av=35, M.sub.n=9555).

[0175] 2.1 Purification

[0176] The solid obtained above was purified by column chromatography (Silica gel 60; eluent 50% dichloromethane in heptane). The columned fractions were then concentrated, dissolved in THF (60 mL) and poured into MeOH (150 mL). The precipitated solid was collected by filtration and dried (14.0 g, n.sub.av=42, M.sub.n=11466). The chromatography/precipitation was repeated two more times (13.5 g, n.sub.av=48, M.sub.n=13104).

[0177] 2.2 Reduction (Oligomer 2)

##STR00012##

[0178] Ammonium formate (45.0 g), Pd/C (10% Pd, 14.0 g) and water (60 mL) were charged to a 500 mL round bottom flask. Oligomer 1 in toluene (120 mL) was then added and the mixture was heated gradually to 85 C. for 8 hours. The mixture was allowed to cool to room temperature overnight. More ammonium formate (20.0 g) and Pd/C (7.0 g) were added and the mixture heated to 85 C. for 8 hours. The mixture was then allowed to cool to room temperature overnight. The catalyst was then removed by filtration through a plug of Celite. The organic layer was separated, dried over MgSO.sub.4, filtered and concentrated. The mixture was then purified by sequential column chromatography (Silica gel 60, eluent 50% dichloromethane in heptane) and precipitation (dissolved in 60 mL THF, poured into 150 mL MeOH and filtered) three times. The final solid was dried (12.8 g, n.sub.av=48, M.sub.n=13104).

3. Preparation of Low Molecular Weight Binder (Oligomer 3)

[0179] ##STR00013##

[0180] A flame dried 500 mL round-bottom flask fitted with a condenser, thermometer and nitrogen inlet was charged with nickel (II) chloride (0.20 g, 1.54 mmol), zinc powder (10.80 g, 165 mmol), 2,2-bipyridyl (0.35 g, 2.24 mmol), triphenylphosphine (7.80 g, 29.7 mmol) and anhydrous N,N-dimethylacetamide (150 mL). The mixture was heated to 70 C., at which point the reaction mixture becomes dark brown/red in colour (characteristic of the formation of a nickel (0) species). The mixture was stirred at 70 C. for a further 30 minutes. Bis(N-4-chlorophenyl)-2-methoxyphenylamine (Compound 1, 20.0 g, 58.1 mmol) was then added in a single charge. After 2 hours toluene (200 mL) was added and the reaction was cooled to room temperature. Concentrated hydrochloric acid as added dropwise to destroy excess zinc. The organic layer was separated and the solvent removed in vacuo. The crude oil obtained was then dissolved in THF (60 mL) and was poured into MeOH (150 mL). The precipitated solid was collected by filtration and dried (15.5 g, n.sub.av=1, M.sub.n=3003). The material was then purified as described below.

[0181] 3.1 Purification

[0182] The solid obtained above was purified by column chromatography (Silica gel 60; eluent 50% dichloromethane in heptane). The columned fractions were then concentrated, dissolved in THF (60 mL) and poured into MeOH (150 mL). The precipitated solid was collected by filtration and dried (12.4 g, n.sub.av=14). The chromatography/precipitation was repeated two more times (11.5 g, n.sub.av=14, M.sub.n=3822).

[0183] Oligomer 3 had a permittivity of 3.5 Fm.sup.1 at 1000 Hz.

[0184] Formulation 1 Oligomer 3 and polyacene 1, (1,4,8,11-tetramethyl-6,13-bis(trimethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s then 1500 rpm for 20 s). Finally an Au gate electrode was deposited by shadow mask evaporation.

[0185] Mobility was 2.5 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length L=30 m).

[0186] 3.2 Reduction (Oligomer 4)

##STR00014##

[0187] Ammonium formate (45.0 g), Pd/C (10% Pd, 14.0 g) and water (60 mL) were charged to a 500 mL round bottom flask. Oligomer 4 in toluene (120 mL) was then added and the mixture was heated gradually to 85 C. for 8 hours. The mixture was allowed to cool to room temperature overnight. More ammonium formate (20.0 g) and Pd/C (7.0 g) were added and the mixture heated to 85 C. for 8 hours. The mixture was then allowed to cool to room temperature overnight. The catalyst was then removed by filtration through a plug of Celite. The organic layer was separated, dried over MgSO.sub.4, filtered and concentrated. The mixture was then purified by sequential column chromatography (Silica gel 60, eluent 50% dichloromethane in heptane) and precipitation (dissolved in 60 mL THF, poured into 150 mL MeOH and filtered) three times. The final solid was dried (10.2 g, n.sub.av=14, M.sub.n=3822).

4. Preparation of 2-Methoxy Polytriarylamine Oligomer by Polymerising 2-Methoxy Aniline with 4,4-Dibromobiphenyl (Oligomer 5)

[0188] ##STR00015##

[0189] A mixture of 2-methoxyaniline (Sigma-Aldrich A88182, 1.54 g, 12.5 mmol), 4,4-biphenyl (Sigma-Aldrich 229237, 7.80 g, 25 mmol, 2 eq.) sodium tert-butoxide (NaO.sup.tBu) (5.05 g, 105 mmol) in toluene (50 mL) was degassed by passing a stream of nitrogen through the solution for 15 minutes. Pd.sub.2dba.sub.3 (Sigma-Aldrich 328774, 0.06 g, 0.15 mol %) and P(tBu).sub.2-o-biphenyl (Sigma-Aldrich 638439, 0.07 g, 0.65 mol %) were then added and the mixture heated to 85 deg C. After approx. 1 hour HPLC confirmed the presence of oligomers. A further charge of 2-methoxyaniline (3.08 g, 25.0 mmol) and NaO.sup.tBu (5.05 g, 105 mmol) were added. After another 2 hours 4,4-biphenyl (7.80 g), Pd.sub.2dba.sub.3 (0.06 g) and P(tBu).sub.2-o-biphenyl (0.07 g) were added and the mixture stirred at 85 deg C. overnight. After a total reaction time of 21 hours the mixture was allowed to cool to room temperature. The mixture was poured into water (150 mL) and filtered through a GF/A filter and the cake washed with THF (50 mL). The organic layer of the filtrate was separated and the aqueous layer was extracted with THF (330 mL). The organic layers were combined, dried (MgSO.sub.4), filtered and concentrated to give a brown semi-solid (15.37 g). The crude product was dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration under suction using a Buchner funnel, washed with methanol (20 mL) and pulled dry (12.3 g). The solid was purified by dry column chromatography eluting with dichloromethane. The fractions containing product were concentrated (11.7 g), the product dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration using a Buchner funnel and was then dried in a vacuum oven (40 deg C.) overnight to give the product as a pale yellow amorphous solid (9.35 g) which was characterised as follows: GPC: Mn=2036 Daltons, N.sub.av=7.

[0190] Oligomer 5 had a permittivity of 3.4 Fm.sup.1 at 1000 Hz; a mobility of 6.310.sup.6 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 2.410.sup.0.5 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m.

[0191] 4.1: Preparation of 4-Methoxy Polytriarylamine Oligomer (2) by Polymerising 4-Methoxy Aniline with 4,4-Dibromobiphenyl (Oligomer 6)

##STR00016##

[0192] A mixture of 4-methoxyaniline (Sigma-Aldrich A88255, 3.08 g, 25.0 mmol), 4,4-biphenyl (15.60 g, 50 mmol, 2 eq.) sodium tert-butoxide (10.10 g, 105 mmol) in toluene (50 mL) was degassed by passing a stream of nitrogen through the solution for 15 minutes. Pd.sub.2dba.sub.3 (0.12 g, 0.3 mol %) and P(tBu).sub.2-o-biphenyl (0.14 g, 1.3 mol %) were then added and the mixture heated to 85 deg C. After approx. 1 hour, HPLC confirmed the presence of oligomers. A further charge of 4-methoxyaniline (6.16 g, 50.0 mmol) and NaO.sup.tBu (10.10 g, 105 mmol) were then added. After a further 2 hours, 4,4-biphenyl (15.6 g), Pd.sub.2dba.sub.3 (0.12 g) and P(tBu).sub.2-o-biphenyl (0.14 g) were added and the mixture stirred at 85 deg C. overnight. After a total reaction time of 18 hours the mixture was allowed to cool to room temperature. The mixture was then poured into water (300 mL), filtered through a GF/A filter and the cake washed with THF (50 mL). The organic layer of the filtrate was separated and the aqueous layer was extracted with THF (330 mL). The organic layers were combined, dried (MgSO.sub.4), filtered and concentrated to give a brown semi-solid (19.79 g). The crude product was dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration under suction using a Buchner funnel and washed with methanol (30 mL) (16.41 g). The solid was purified by dry column chromatography (eluent: dichloromethane/THF). The fractions containing product were concentrated (14.4 g), the product dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration using a Buchner funnel. The material was purified using dry column chromatography, eluting with dichloromethane (DCM; 7.30 g). The product was then dissolved in THF (50 mL) and precipitated into methanol (100 mL). The solid was collected by filtration and was then dried in a vacuum oven (40 deg C.) overnight to give the product as a pale yellow amorphous solid (6.40 g) which was characterised as follows: GPC Mn=1307 Daltons, N.sub.av=5.

[0193] Oligomer 6 had a permittivity of 3.5 Fm.sup.1 at 1000 Hz; a mobility of 4.210.sup.5 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 1.010.sup.4 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m.

[0194] Formulation 2

[0195] Oligomer 6 and polyacene 1, (1,4,8,11-tetramethyl-6,13-bis(trimethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s then 1500 rpm for 20 s). Finally an Au gate electrode was deposited by shadow mask evaporation. Mobility was 4.00 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length L=30 m).

6. Reduction of the 4-Methoxy Polytriarylamine Oligomer to Afford Oligomer 7

[0196] ##STR00017##

[0197] 4-methoxy polymer (Oligomer 6, 2.50 g) was dissolved in toluene (20 mL) in a three-necked flask fitted with a condenser. Ammonium formate (10.0 g, 159 mmol) and Pd on activated carbon (10% Pd, 2.5 g) were added and the mixture heated to 65 deg C. After 14 hours a further charge of ammonium formate (10.0 g, 159 mmol) and Pd on activated carbon were added and the mixture stirred at 65 deg C. for a further 6 hours. The mixture was allowed to cool, water (20 mL) was added and the organic layer separated. The organic layer was dried over MgSO.sub.4, filtered and concentrated to give a cream coloured semi-solid (2.31 g). The solid was dissolved in THF (30 mL) and the oligomer precipitated by pouring slowly into methanol (60 mL) with stirring. The precipitated solid was collected by filtration. The solid was then purified by dry column chromatography (eluent 1:1 DCM:THF) three times. The mixture as then dissolved in THF (30 mL) and precipitated into methanol (60 mL) and collected by filtration. (2.20 g), which was characterised as follows: GPC Mn=1313 Daltons, N.sub.av=5.

[0198] Oligomer 7 had a permittivity of 3.5 Fm.sup.1 at 1000 Hz.

[0199] Formulation 3

[0200] Oligomer 7 and polyacene 1 (1,4,8,11-tetramethyl-6,13-bis(trimethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s, then 1500 rpm for 20 s). Finally an Au gate electrode was deposited by shadow mask evaporation.

[0201] Mobility was 4.5 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length L=30 m) and 4.1 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length L=4 m).

7. Preparation of Bis(N-4-Chlorophenyl)-4-Methoxyphenylamine (Compound 2)

[0202] ##STR00018##

[0203] A mixture of 4-methoxyaniline (60.50 g, 491 mmol), 1-chloro-4-iodobenzene (292.87 g, 1228 mmol), anhydrous potassium carbonate (244.40 g, 1770 mmol), copper powder (93.66 g, 1474 mmol), 18-crown-6 ether (32.46 g, 123 mmol) and anhydrous ortho-dichlorobenzene (o-DCB, 100 mL), were charged to a 700 mL flange flask, fitted with a Dean-Stark trap, thermometer, overhead stirrer and water condenser, and flushed with nitrogen for 10 mins. The mixture was heated to 170 deg C. and stirred for. After 72 hours the mixture was allowed to cool to room temperature and was then filtered through a GF/A filter paper. The cake was washed with DCM (800 mL and the combined filtrates were washed with water (HPLC grade, 250 mL2). The combined aqueous layers were back-extracted with DCM (200 mL2), combine and dried over MgSO.sub.4. The filter cake was washed with DCM (150 mL2) and the combined filtrates concentrated in vacuo to give a brown semi-solid (227.12 g). The crude product was dissolved in heptane (200 mL) and purified by dry column chromatography (gradient elution: heptane-10% DCM: 1.5 heptane) gave a pale yellow viscous oil, 101.87 g. .sup.1H NMR (500 MHz, CDCl.sub.3) 7.16 (4H, d, J=8.8 Hz), 7.02 (2H, d, J=8.8 Hz), 6.93 (4H, d, J=8.8 Hz), 6.84 (2H, d, J=8.8 Hz), 3.80 (3H, s, OCH.sub.3).

8. Preparation of 4-Methoxy Polytriarylamine Oligomer 8 by Polymerising the Amine Monomer (as Prepared in Example 2(c))

[0204] ##STR00019##

[0205] A 500 mL flange flask, fitted with a thermometer, overhead stirrer and water condenser, was flame-dried under nitrogen purge to 100 deg C., then allowed to cool to ambient temperature. Nickel(II) chloride (0.098 g, 0.76 mmol), zinc powder (5.92 g, 90.61 mmol), 2-bipyridyl (0.18 g, 1.13 mmol), triphenylphosphine (3.94 g, 15.03 mmol) and anhydrous DMAc (90 mL) were charged in and the grey suspension stirred at 20 deg C. for 15 mins. The mixture was then heated to 70 deg C. The burgundy colour of the catalyst forms as the temperature increases. Stirring was continued at 70 deg C. for a further 20 mins to allow the catalyst to stabilise, then a solution of the 4-methoxy monomer (Example 2(c), 10 g) in anhydrous DMAc (10 mL) was added to the flange flask and stirring continued for 4.5 h. After 4 h, solids start to precipitate. The mixture was allowed to cool to 25 deg C. Toluene (210 mL) was added and the stirred mixture was then cooled in an ice/water bath to 15 deg C., then concentrated hydrochloric acid (37%, 35 mL) was added dropwise (exotherm to 30 deg C.). The mixture was stirred for 10 mins, filtered and the filtrate transferred to a separating funnel. The filter cake were stirred in THF (300 mL) and filtered. This filtrate was combined with the organic layer from the separating funnel and concentrated in vacuo to give a yellow semi-solid (20.33 g). The material was dissolved in THF (60 mL) then poured slowly into methanol (180 mL). The precipitated solid was isolated by filtration (6.33 g) and purified by dry column chromatography (eluent: THF). After the final column the solid obtained was dissolved in THF (20 mL) and poured slowly into methanol (60 mL), the precipitated solid was collected by filtration under suction using a Buchner funnel, washed with methanol and pulled dry. The solid was then dried in a vacuum oven to give the product as a yellow powder (5.42 g), which was characterised as follows: GPC Mn=2405 Daltons, N.sub.av=9.

[0206] Oligomer 8 had a permittivity of 3.5 Fm.sup.1 at 1000 Hz; a mobility of 6.010.sup.5 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 4.510.sup.4 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m

[0207] Formulation 4

[0208] Oligomer 8 and polyacene 1 (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s, then 1500 rpm for 20 s). Finally an Au gate electrode was described by shadow mask evaporation.

[0209] Mobility was 2.6 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length L=30 m).

9. 4-Ethoxy Polytriarylamine Oligomer (Oligomer 9)

[0210] Preparation of 4-Ethoxy Polytriarylamine Oligomer by Polymerising 4-Ethoxy Aniline with 4,4-Dibromobiphenyl

##STR00020##

[0211] A mixture of 4-ethoxyaniline (Sigma-Aldrich P14815, 1.71 g, 12.5 mmol), 4,4-biphenyl (7.80 g, 25.0 mmol) sodium tert-butoxide (5.05 g, 52.6 mmol) in toluene (50 mL) was degassed by passing a stream of nitrogen through the solution for 15 minutes. Pd.sub.2dba.sub.3 (0.06 g, 0.15 mol %) and P(tBu).sub.2-o-biphenyl (0.07 g, 0.65 mol %) were then added and the mixture heated to 85 deg C. After approx. 1 hour HPLC confirmed the presence of oligomers. Further amounts of 4-ethoxyaniline (3.42 g, 24.9 mmol) and NaO.sup.tBu (5.05 g, 52.6 mmol) were then added. After another 2 hours 4,4-biphenyl (7.80 g, 25.0 mmol), Pd.sub.2dba.sub.3 (0.06 g, 0.15 mol %) and P(tBu).sub.2-o-biphenyl (0.07 g, 0.65 mol %) were added and the mixture stirred at 85 deg C. overnight. After a total reaction time of 20 hours the mixture was allowed to cool to room temperature. The mixture was then poured into water (300 mL). The mixture was filtered through a GF/A filter and the cake washed with toluene (50 mL). The organic layer of the filtrate was separated and the aqueous extracted with toluene (330 mL). The organic layers were combined, dried over MgSO.sub.4, filtered and concentrated to give a brown semisolid (18.20 g). The crude product was dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration under suction using a Buchner funnel and pulled dry (13.56 g). The solid was purified by dry column chromatography (eluent: dichloromethane). The fractions containing product were concentrated, the product (10.92 g) dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration (Whatman No. 1 paper). The solid was then dried in a vacuum oven (40 deg C.) overnight to give the product as a cream coloured amorphous solid (8.10 g), which was characterised as follows: GPC Mn=1539 Daltons, N.sub.av=5.

[0212] Oligomer 9 had a permittivity of 3.7 Fm.sup.1 at 1000 Hz; a mobility of 6.210.sup.6 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 1.010.sup.6 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at channel length, L=40=m

[0213] Formulation 5

[0214] Oligomer 9 and polyacene 1 (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in bromomesitylene at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s then 1500 rpm for 20 s). Finally an Au gate electrode was described by shadow mask evaporation.

[0215] Mobility was 3.1 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length 100 m).

10. Preparation of Bis(N-4-Chlorophenyl)-2,4-Dimethoxyphenylamine (Compound 3)

[0216] ##STR00021##

[0217] A mixture of 2,4-dimethoxyaniline (TCI Europe D1982, 60.00 g, 391 mmol), 1-chloro-4-iodobenzene (233.51 g, 979 mmol), anhydrous potassium carbonate (194.89 g, 1410 mmol), copper powder (71.48 g, 1.12 mmol).22 g, 1089, 18-crown-6 ether (25.88 g, 97.9 mmol) and anhydrous o-DCB (100 mL) were charged to a 700 mL flange flask, fitted with a Dean-Stark trap, thermometer, overhead stirrer and water condenser, and flushed with nitrogen for 10 mins. The mixture was heated to between 170 deg C. After 3 hr the mixture was allowed to cool to room temperature, DCM (500 mL) was added and the mixture filtered through a GF/A filter paper. The cake washed with DCM (200 mL). The combined filtrates were washed with water (250 mL2) and the combined aqueous layers back-extracted with DCM (200 mL2). The organic layers were combined, dried over MgSO.sub.4 (30 mins) and filtered. The filter cake was washed with further DCM (150 mL2) and the combined filtrates concentrated in vacuo to give a brown semi-solid (181.11 g). The crude product was dry loaded onto silica gel and purified by dry flash column chromatography (gradient elution: heptanes-15% DCM:heptane) to give a colourless solid (72.95 g). The product was recrystallised from heptane to give a colourless crystalline solid (62.89 g, 43%). .sup.1H NMR (500 MHz) 7.13 (2H, d, J=8.8 Hz), 7.06 (2H, d, J=9.0 Hz), 6.89 (2H, d, J=8.8 Hz), 6.54 (1H, d, J=2.5 Hz), 6.49 (2H, m), 3.83 (3H, s), 3.65 (3H, s).

11. Preparation of 2,4-Dimethoxy Polytriarylamine Oligomer (10) by Polymerising the Amine Monomer Compound 3

[0218] ##STR00022##

[0219] A 500 mL flange flask, fitted with a thermometer, overhead stirrer and water condenser, was flame-dried under nitrogen purge to 100 deg C., then allowed to cool to ambient temperature. Nickel(II) chloride (0.10 g, 0.76 mmol), zinc powder (5.91 g, 90.6 mmol), 2-bipyridyl (0.18 g, 1.13 mmol), triphenylphosphine (3.93 g, 15.03 mmol) and anhydrous DMAc (90 mL) were charged and the grey suspension stirred at 20 deg C. for 15 mins. The mixture was then heated to 70 deg C., during which time the reaction mixture became burgundy in colour (indicative of the formation of a Ni(0) species). Stirring was continued at 70 deg C. for a further 20 mins to allow the catalyst to stabilise, then a solution of the 2,4-dimethoxy monomer (Example 4(a)) (10.94 g, 29.2 mmol) was added to the flange flask and stirring continued for 5.5 h. The mixture was allowed to cool to 25 deg C. Toluene (100 mL) was added and the stirred mixture cooled in an ice/water bath to 15 deg C., then concentrated hydrochloric acid, 37% (35 mL) was added dropwise (exotherm to 30 deg C.). The mixture was stirred for 10 mins, filtered and the filtrate transferred to a separating funnel. The organic layer was separated and was then concentrated in vacuo to give a green semisolid (13.91 g). This was dissolved in THF (40 mL) and precipitated into MeOH (120 mL). The solid was isolated by filtration under suction using a Buchner funnel and the filter cake washed with MeOH (60 mL). The solid was then dried in a vacuum oven (9.37 g). The solid was purified by dry column chromatography (eluent THF) three times to give the product as a yellow powder (8.05 g), which was characterised as follows: GPC Mn=4643 Daltons, N.sub.av=15.

[0220] Oligomer 10 had a permittivity of 3.5 Fm.sup.1 at 1000 Hz; a mobility of 3.910.sup.5 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 2.310.sup.4 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m

12. Preparation of 3,4,5-Trimethoxy Poytriarylamine Oligomer (Oligomer 11) by Polymerizing 3,4,5-Trimethoxy Aniline with 4,4-Dibromobiphenyl

[0221] ##STR00023##

[0222] A mixture of 3,4,5-trimethoxyaniline (Fluorochem 008860, 2.28 g, 12.6 mmol), 4,4-biphenyl (7.80 g) sodium tert-butoxide (5.05 g) in toluene (50 mL) was degassed by passing a stream of nitrogen through the solution for 15 minutes. Pd.sub.2dba.sub.3 (0.06 g) and P(tBu).sub.2-o-biphenyl (0.07 g) were then added and the mixture heated to 85 deg C. After approx. 1 hour, HPLC confirmed the presence of oligomers. Further amounts of 4-ethoxyaniline (3.42 g) and NaO.sup.tBu (5.05 g) were then added. After another 2 hours 4,4-biphenyl (7.8 g), Pd.sub.2dba.sub.3 (0.06 g) and P(tBu).sub.2-o-biphenyl (0.07 g) were added and the mixture stirred at 85 deg C. overnight. After a total reaction time of 20 hours the mixture was allowed to cool to room temperature. and poured into water (300 mL). The mixture was filtered through a GF/A filter and the cake washed with toluene and THF. The organic layer of the filtrate was separated and the aqueous extracted with THF (330 mL). The organic layers were combined, dried (MgSO.sub.4), filtered and concentrated to give a brown semisolid (21.23 g). The crude product was dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration (Whatman No. 1 paper) and pulled dry (15.17 g). The solid was purified by dry column chromatography (eluent: dichloromethane followed by THF). The THF fractions were concentrated (10.0 g). The product was dissolved in THF (50 mL) and added dropwise into methanol (100 mL). The precipitated solid was collected by filtration (9.6 g). This material was purified again by dry column chromatography (eluent THF), the fractions collected were concentrated, dissolved in THF (50 mL) and poured into methanol (100 mL). The solid was collected by filtration and then dried in a vacuum oven (40 deg C.) overnight to give the product as a cream coloured amorphous solid (7.3 g), which was characterised as follows: GPC Mn=2502 Daltons, N.sub.av=8.

[0223] Oligomer 11 had a permittivity of 3.9Fm.sup.1 at 1000 Hz; a mobility of 6.010.sup.6 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 1.410.sup.6 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m

[0224] Formulation 6

[0225] Oligomer 11 and polyacene 1 (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in tetralin at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s then 1500 rpm for 20 s). Finally an Al gate electrode was described by shadow mask evaporation.

[0226] Mobility was 2.0 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length 35 m).

13. Bis(4-chlorophenyl)amine (Compound 4)

[0227] ##STR00024##

[0228] 4-Chlorobenzeneboronic acid (45.00 g, 287 mmol), hydroxylamine hydrochloride (23.99 g, 345 mmol), anhydrous potassium carbonate (59.66 g, 432 mmol), copper(I) bromide (8.23 g, 57 mmol) and MeCN (500 mL) were charged to a 1 L 3-necked round-bottomed flask, fitted with a two-way adapter, thermometer, overhead stirrer and air condenser. The blue coloured reaction mixture was heated to 70 deg C. (became brown after about 40 mins). After 66 h, the brown mixture was allowed to cool to room temperature, and then filtered using a Buchner funnel. The filter cake was washed with acetonitrile (MeCN, 100 mL) and DCM (200 mL). The cake was then slurried in DCM (200 mL) for 10 mins and filtered via suction using a Buchner funnel. The combined filtrates were evaporated in vacuo to afford a brown semisolid (22.28 g). The crude product was dissolved in DCM and dry loaded onto silica gel then purified by dry column chromatography, (gradient elution: 10% DCM: heptane then 20% DCM: heptane) to give the product as a brown solid (10.37 g). Recrystallisation from methanol gave the product as a yellow sold (9.29 g, 14%). .sup.1H NMR (500 MHz) 7.22 (4H, d, J=8.7 Hz), 6.96 (4H, d, J=8.7 Hz), 5.63 (1H, b, NH).

14. Preparation of bis(N-4-chlorophenyl)-2-cyanophenylamine

[0229] ##STR00025##

[0230] Bis(4-chlorophenyl)amine (Compound 4, 3.07 g, 12.89 mmol) and anhydrous NMP (32 mL) were charged to a 100 mL, 3-necked round-bottomed flask, fitted with a stirrer flea, nitrogen inlet/bubbler, water condenser, thermometer, and a 2M NaOH aqueous solution scrubber, followed by 2-fluorobenzonitrile and caesium fluoride. The red mixture was degassed for 30 mins, and then heated to 175 deg C. (The reaction mixture slowly becomes dark brown). After 16 h, analysis by liquid chromatography (LC) indicated the reaction was complete. The reaction mixture was allowed to cool to room temperature, diluted with toluene (190 mL) in a conical flask, dried over magnesium sulphate (30 mins) and filtered via suction. The filter cake washed with further toluene (50 mL) and pulled dry. The combined filtrates were evaporated in vacuo (48 deg C.), then under high vacuum at 94 deg C. for 6.5 h, to give to leave a brown oil (4.77 g). The crude product was recrystallized slowly from methanol (45 mL, 10 vols), cooled to 6 deg C., filtered and washed with cold (18 deg C.) methanol (30 mL). This was dried in vacuo (vacuum oven, 40 deg C., 69 h) to give the desired product as brown needles (3.75 g, 85%). .sup.1H NMR (600 MHz, CDCl.sub.3) 7.60 (1H, dd, J=7.8 Hz, 1.6 Hz), 7.52-7.50 (1H, m), 7.24 (4H, d, J=8.9 Hz), 7.22-7.17 (2H, m), 6.94 (4H, d, J=8.9 Hz).

15. Preparation of 2-Cyano Polytriarylamine Oligomer (Oligomer 12) by Polymerising the Amine Monomer (Compound 5)

[0231] ##STR00026##

[0232] A 250 mL flange flask, fitted with a thermometer, overhead stirrer and water condenser, was flame-dried under nitrogen purge to 100 deg C., then allowed to cool to ambient temperature. Nickel(II) chloride (0.05 g, 0.39 mmol), zinc powder (3.02 g, 46.13 mmol), 2,2-bipyridyl (0.090 g, 0.58 mmol), triphenylphosphine (2.00 g, 7.65 mmol) and anhydrous DMAc (80 mL) were charged in and the grey suspension stirred at 20 deg C. for 25 mins. The mixture was then heated to 70 deg C. (the burgundy colour of the catalyst formed as the mixture was heated) and held at 70 deg C. for a further 30 mins to allow the catalyst to stabilise. The monomer (5.02 g, 14.80 mmol) was added to the flange flask, rinsed in with anhydrous DMAc (10 mL) and stirring continued for 22 hr. The mixture was allowed to cool to 45 deg C., then toluene (90 mL) was added and the stirred mixture cooled in an ice/water bath to 10 deg C, then concentrated hydrochloric acid, 37% (35 mL) was added dropwise (exotherm to 25 deg C.; red colour disappears, turns grey/green). THF (80 mL) was added, the suspension was stirred for 15 mins and was then transferred to a separating funnel. The organic layer was separated, the aqueous layer extracted with THF and concentrated give a brown semisolid (11.21 g). The residue was taken up in THF (56 mL) then the solution added dropwise to rapidly-stirred methanol (260 mL) and the precipitated solid was filtered under suction using a Buchner funnel, the filter cake washed with methanol (240 mL) and pulled dry. The filter cake (22.78 g) was dried in a vacuum oven to leave a yellow powder (3.66 g). The material was purified by dry column chromatography (eluent: THF) three times. The product obtained (3.52 g) was dissolved in THF (11 mL) and poured slowly into methanol (33 mL). The precipitated solid was filtered under suction using a Buchner funnel, the filter cake washed with methanol and pulled dry. The solid was then dried in a vacuum oven to give the product as a yellow solid (2.94 g), which was characterised as follows: GPC Mn=2688 Daltons, N.sub.av=8.

[0233] Oligomer 12 had a permittivity of 3.5 Fm.sup.1 at 1000 Hz. a mobility of 1.910.sup.6 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 3.210.sup.6 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m

16. Preparation of Bis(N-4-Chlorophenyl)-4-Cyanophenylamine (Compound 6)

[0234] ##STR00027##

[0235] A 500 mL 3-necked round-bottomed flask, fitted with a thermometer, overhead stirrer, a two-way adapter nitrogen inlet/bubbler and water condenser, was flushed with nitrogen for 30 mins, then bis(4-chlorophenyl)amine (Example 6(a), 6.22 g, 26.13 mmol), 4-bromobenzonitrile (5.23 g, 28.75 mmol), NaO.sup.tBu (3.19 g, 33.18 mmol), 1,1-bis(diphenylphosphino)ferrocene (0.78 g, 1.41 mmol) and anhydrous toluene (280 mL) were charged. The red/brown mixture was degassed for 38 mins, and then Pd.sub.2(dba).sub.3 (0.43 g, 0.47 mmol) was added and the mixture heated to 80 deg C. under nitrogen. After 18 hrs, an extra 0.5 equiv. of 4-bromobenzonitrile (2.38 g) was added. After a further two hours another charge of catalyst (Pd.sub.2(dba).sub.3, 0.43 g), 1,1-bis(diphenylphosphino)ferrocene) (0.78 g 1.41 mmol) and NaO.sup.tBu (1.27 g) were added and heating continued overnight. After a total of 41 h, LC indicated the reaction was complete and it was allowed to cool to room temperature, diluted with water (250 mL), stirred for 10 mins, then transferred to a separating funnel and the phases allowed to separate. The bottom aqueous phase was removed and back-extracted with toluene (200 mL), and the combined organic extracts washed with brine (250 mL), dried over MgSO.sub.4 (15 mins) and filtered under suction using a Buchner funnel and the filter cake washed with toluene (200 mL). The combined filtrates were evaporated in vacuo (50 deg C.) to afford a red/brown powder (14.87 g). The crude product was purified by dry flash column chromatography (gradient elution: 10% DCM/heptane to 50% DCM/heptane) to give the product as a yellow solid (7.99 g, 90%). .sup.1H NMR (600 MHz, CDCl.sub.3) 7.44 (2H, d, J=8.6 Hz), 7.28 (4H, d, J=8.6 Hz), 7.04 (4H, d, J=8.6 Hz), 6.95 (2H, d, J=8.6 Hz).

17. Preparation of 4-Cyano Polytriarylamine Oligomer (Oligomer 13) by Polymerising the Amine Monomer (Compound 6)

[0236] ##STR00028##

[0237] A 250 mL flange flask, fitted with a thermometer, overhead stirrer and water condenser, was flame-dried under nitrogen purge to 100 deg C., then allowed to cool to ambient temperature. Nickel(II) chloride (0.09 g, 0.69 mmol) zinc powder (5.38 g, 82.38 mmol), 2,2-bipyridyl (0.16 g, 1.03 mmol), triphenylphosphine (3.58 g, 13.66 mmol) and anhydrous DMAc (80 mL) were charged and the grey suspension stirred at 20 deg C. for 25 mins. The burgundy colour of the catalyst formed after 15 mins at ambient temperature. The mixture was then heated to 70 deg C. and held at 70 deg C. for a further 30 mins to allow the catalyst to stabilise. The monomer (Example 7(a), 8.96 g) was added to the flange flask, rinsed in with anhydrous DMAc (10 mL) and stirring continued for 5 h. The mixture was allowed to cool to 45 deg C, then toluene (90 mL) was added and the stirred mixture cooled in an ice/water bath to 10 deg C., then concentrated hydrochloric acid, 37% (35 mL) was added dropwise (exotherm to 25 deg C.; mixture became grey/green in colour). THF (80 mL) was added; the suspension was stirred for 15 mins and was then transferred to a separating funnel. The organic layer was separated, the aqueous layer extracted with THF (240 mL). The combined organic extracts were concentrated give a green semi-solid (21.25 g). The residue was taken up in THF (90 mL) then the solution added dropwise to rapidly-stirred methanol (260 mL) and the precipitated solid collected by filtration using a Buchner funnel and washed with methanol (240 mL). The filter cake (40.04 g) was dried in a vacuum oven to afford a deep yellow powder (7.11 g). The material was purified by dry column chromatography (eluent: THF) three times. The product obtained (3.52 g) was dissolved in THF (1 mL) and poured slowly into methanol (33 mL). The precipitated solid was collected by filtration under suction using a Buchner funnel and the filter cake washed with methanol (30 mL). The solid (10.09 g) was then dried in a vacuum oven to give the product as a yellow solid (5.38 g), which was characterised as follows: GPC Mn=3341 Daltons, N.sub.av=10.

[0238] Oligomer 13 had a permittivity of 3.4 Fm.sup.1 at 1000 Hz. a mobility of 9.110.sup.7 cm.sup.2V.sup.1 s.sup.1 (linear mobility) and 8.410.sup.7 cm.sup.2V.sup.1 s.sup.1 (saturation mobility) at a channel length, L=40 m

[0239] Formulation 7

[0240] Oligomer 13 and polyacene 1 (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (1:1 ratio by weight) were dissolved in 1,2-dichlorobenzene at 2% total solids and spin coated (500 rpm for 5 s, then 1500 rpm for 60 s) onto patterned Au source/drain electrodes (50 nm thick Au treated with a 10 mM solution of pentafluorobenzene thiol in isopropyl alcohol). The fluoropolymer dielectric Cytop (Asahi Chemical Co.) was spin coated on top (500 rpm for 5 s then 1500 rpm for 20 s). Finally an Al gate electrode was described by shadow mask evaporation.

[0241] Mobility was 0.6 cm.sup.2V.sup.1 s.sup.1 (linear mobility, channel length 35 m).

Comparative Example 1

2,4 Dimethyl Polytriarylamine Oligomer

[0242] 2,4-dimethyl polytriarylamine (N.sub.av=18) was obtained from High Force Research Ltd (Durham, UK). Comparative Example 1 had a permittivity of 3.0 Fm.sup.1 at 1000 Hz.