Organic semiconductor compositions

Abstract

The present invention relates to organic copolymers and organic semiconducting compositions comprising these materials, including 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 in the field of printed electronics and is particularly useful as the semiconducting material for use in formulations for organic thin film-transistor (OFET) backplanes for displays, integrated circuits, organic light emitting diodes (OLEDs), photodetectors, organic photovoltaic (OPV) cells, sensors, memory elements and logic circuits.

Claims

1. A polycyclic aromatic hydrocarbon copolymer (PAHC) comprising a mixture of at least one polyacene monomer unit having the Formula (A) and at least one monomer unit having the Formula (B): ##STR00041## wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.14, which may be the same or different, independently represents hydrogen; a branched or unbranched, substituted or unsubstituted C.sub.1-C.sub.40 alkyl group; a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.40 alkenyl group; a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.40 alkynyl group; an optionally substituted C.sub.3-C.sub.40 cycloalkyl group; an optionally substituted C.sub.6-C.sub.40 aryl group; an optionally substituted C.sub.1-C.sub.40 heterocyclic group; an optionally substituted C.sub.1-C.sub.40 heteroaryl group; an optionally substituted C.sub.1-C.sub.40 alkoxy group; an optionally substituted C.sub.6-C.sub.40 aryloxy group; an optionally substituted C.sub.7-C.sub.40 alkylaryloxy group; an optionally substituted C.sub.2-C.sub.40 alkoxycarbonyl group; an optionally substituted C.sub.7-C.sub.40 aryloxycarbonyl group; a cyano group (—CN); a carbamoyl group (—C(═O)NR.sup.15R.sup.16); a carbonyl group (—C(═O)—R.sup.17); a carboxyl group (—CO.sub.2R.sup.18) a cyanate group (—OCN); an isocyano group (—NC); an isocyanate group (—NCO); a thiocyanate group (—SCN) or a thioisocyanate group (—NCS); an optionally substituted amino group; a hydroxy group; a nitro group; a CF.sub.3 group; a halo group (Cl, Br, F, I); —SR.sup.19; —SO.sub.3H; —SO.sub.2R.sup.20; —SF.sub.5; an optionally substituted silyl group; a C.sub.2-C.sub.10 alkynyl group substituted with a —SiH.sub.2R.sup.2 group, a C.sub.2-C.sub.10 alkynyl substituted with a —SiHR.sup.22R.sup.23 group, or a C.sub.2-C.sub.10 alkynyl moiety substituted with a —Si(R.sup.22).sub.x(R.sup.23).sub.y(R.sup.24).sub.z group; wherein each R.sup.22 group is independently selected from the group consisting of a branched or unbranched, substituted or unsubstituted C.sub.1-C.sub.10 alkyl group, a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.10 alkynyl group, a substituted or unsubstituted C.sub.2-C.sub.20 cycloalkyl group, a substituted or unsubstituted C.sub.2-C.sub.10 alkenyl group, and a substituted or unsubstituted C.sub.6-C.sub.20 cycloalkylalkylene group; each R.sup.23 group is independently selected from the group consisting of a branched or unbranched, substituted or unsubstituted C.sub.1-C.sub.10 alkyl group, a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.10 alkynyl group, a substituted or unsubstituted C.sub.2-C.sub.10 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.20 cycloalkyl group, and a substituted or unsubstituted C.sub.6-C.sub.20 cycloalkylalkylene group; R.sup.24 is independently selected from the group consisting of hydrogen, a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.10 alkynyl group, a substituted or unsubstituted C.sub.2-C.sub.20 cycloalkyl group, a substituted or unsubstituted C.sub.6-C.sub.20 cycloalkylalkylene group, a substituted C.sub.5-C.sub.20 aryl group, a substituted or unsubstituted C.sub.6-C.sub.20 arylalkylene group, an acetyl group, a substituted or unsubstituted C.sub.3-C.sub.20 heterocyclic ring comprising at least one of O, N, S and Se in the ring; wherein x=1 or 2; y=1 or 2; z=0 or 1; and (x+y+z)=3; wherein each of R.sup.15, R.sup.16, R.sup.18, R.sup.19 and R.sup.20 independently represent H or optionally substituted C.sub.1-C.sub.40 carbyl or hydrocarbyl group optionally comprising one or more heteroatoms; wherein R.sup.17 represents a halogen atom, H or optionally substituted C.sub.1-C.sub.40 carbyl or C.sub.1-C.sub.40 hydrocarbyl group optionally comprising one or more heteroatoms; wherein k and I are independently 1 or 2; wherein at least two of 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 a bond, represented by ------*, to another monomer unit having the Formula (A) or (B), and 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 preferably at least one of Ar.sub.1, Ar.sub.2 and Ar.sub.3 is substituted with at least one polar or more polarising group.

2. A PAHC according to claim 1, comprising at least 20 to 40% of monomer (A) and at least 60 to 80% of monomer (B), based on the total of all monomer units (A) and (B) in the copolymer.

3. A PAHC according to claim 1, wherein k=I.

4. A PAHC according to claim 1, wherein the copolymers have a number average molecular weight (Mn) of between 400 and 100,000.

5. A PAHC according to claim 1, wherein the copolymers are semiconducting copolymers having a permittivity at 1000 Hz of greater than 1.5.

6. A PAHC according to claim 5, wherein the copolymers are semiconducting copolymers having a permittivity at 1000 Hz of between 3.4 and 8.0.

7. A PAHC according to claim 1, wherein at least one of groups R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.14 are (tri-C.sub.1-20 hydrocarbylsilyl)C.sub.1-4alkynyl-groups.

8. A PAHC according to claim 7, wherein at least 2 of groups R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.14are (tri-C.sub.1-20 hydrocarbylsilyl)C.sub.1-4 alkynl-groups.

9. A PAHC according to claim 1, wherein R.sup.5, R.sup.7, R.sup.12 and R.sup.14 are hydrogen.

10. A PAHC according to claim 1, wherein —Si(R.sup.22).sub.x(R.sup.23).sub.y(R.sup.24).sub.z is selected from the group consisting of trimethylsilyl, triethylsilyl, tripropylsilyl, dimethylethylsilyl, diethylmethylsilyl, dimethylpropylsilyl, dimethylisopropylsilyl, dipropylmethylsilyl, diisopropylmethylsilyl, dipropylethylsilyl, diisopropylethylsilyl, diethylisopropylsilyl, triisopropylsilyl, trimethoxysilyl, triethoxysilyl, triphenylsilyl, diphenylisopropylsilyl, diisopropylphenylsilyl, diphenylethylsilyl, diethylphenylsilyl, diphenylmethylsilyl, triphenoxysilyl, dimethylmethoxysilyl, dimethylphenoxysilyl, and methylmethoxyphenyl.

11. A PAHC according to claim 1, having the Formula (A1) or (A2) ##STR00042## wherein R.sup.25, R.sup.26 and R.sup.27 are independently selected from the group consisting of C.sub.1-C.sub.6 alkyl and C.sub.2-C.sub.6 alkenyl, preferably independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, 1-propenyl and 2-propenyl, more preferably ethyl, n-propyl and isopropyl.

12. A PAHC according to claim 1, wherein the polyacene monomer units have the Formulae (A3) and (A4): ##STR00043## wherein R.sup.25, R.sup.26 and R.sup.27 are independently selected from the group consisting of methyl, ethyl and isopropyl.

13. A PAHC according to claim 1, wherein the polyacene monomer unit is selected from the following units (A5) to (A8): ##STR00044## ##STR00045##

14. A PAHC according to claim 1, wherein monomer unit (B) having the, Ar.sub.1, Ar.sub.2 and Ar.sub.3, which may be the same or different, each representing, independently if in different repeat units, an optionally substituted C.sub.6-20 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 or more polar or polarising group, and n=1 to 20.

15. A PAHC according to claim 14, wherein the one or more polar or polarising group(s) 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.

16. A PAHC according to claim 14, 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, CN and mixtures thereof, and n=1 to 10.

17. A PAHC according to claim 1, further comprising one or more monomers (C), (D), (D′) and/or (E): ##STR00046## wherein each R.sup.1′, R.sup.2′, R.sup.3′, R.sup.4′, R.sup.5, R.sup.6 and R.sup.7, each of which may be the same or different, is selected from the same group as R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 and R.sup.7, as defined in claim 1; wherein n′=1 to 3; and wherein monomer (A) is present in an amount of at least 20 wt. %; monomer (B) is present in an amount of at least 60 wt. % and the remainder is comprised of monomers (C), (D), (D′) and/or (E), based on the total weight of all monomer units in the copolymer.

18. An organic semiconductor composition comprising a PAHC according to claim 1 and a polyacene small molecule, wherein the PAHC has a permittivity at 1000 Hz of between 3.4 and 8.0 or between 3.4 and 4.5.

19. An organic semiconductor composition according to claim 18, having a charge mobility value of at least 0.5 cm.sup.2V.sup.−1s.sup.−1, preferably between 2 and 5.0 cm.sup.2V.sup.−1s.sup.−1.

20. An organic semiconductor composition according to claim 18, wherein said composition is embedded in an semiconductor layer or electronic device comprising said organic semiconductor composition.

21. An an organic semiconductor composition according to claim 20, wherein the electronic device is selected from organic field effect transistors (OFETS), organic light emitting diodes (OLEDS), photodetectors, organic photovoltaic (OPV) cells, sensors, lasers, memory elements and logic circuits.

22. An organic semiconductor composition comprising a Polycyclic Aromatic Hydrocarbon Copolymer (PAHC) according to claim 1, wherein the composition has a permittivity at 1000 Hz of between 3 and 6.5, between 3.4 and 8 or between 4 and 6.5.

23. An ink comprising a PAHC according to claim 1.

24. A PAHC according to claim 1, wherein at least one of groups R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.14are (trihydrocarbylsilyl)ethynyl-groups.

25. A PAHC according to claim 1, wherein at least 2 of groups R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.14are (trihydrocarbylsilyl)ethynyl-groups.

26. A process for producing a polycyclic aromatic hydrocarbon copolymer (PAHC) comprising copolymerising a composition containing at least one polyacene monomer unit selected from the structures (A′) and (B′), ##STR00047## wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13 and R.sup.14, which may be the same or different, independently represents hydrogen; a branched or unbranched, substituted or unsubstituted C.sub.1-C.sub.40 alkyl group; a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.40 alkenyl group; a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.40 alkynyl group; an optionally substituted C.sub.3-C.sub.40 cycloalkyl group; an optionally substituted C.sub.6-C.sub.40 aryl group; an optionally substituted C.sub.1-C.sub.40 heterocyclic group; an optionally substituted C.sub.1-C.sub.40 heteroaryl group; an optionally substituted C.sub.1-C.sub.40 alkoxy group; an optionally substituted C.sub.6-C.sub.40 aryloxy group; an optionally substituted C.sub.7-C.sub.40 alkylaryloxy group; an optionally substituted C.sub.2-C.sub.40 alkoxycarbonyl group; an optionally substituted C.sub.7-C.sub.40 aryloxycarbonyl group; a cyano group (—CN); a carbamoyl group (—C(═O)NR.sup.15R.sup.16); a carbonyl group (—C(═O)—R.sup.17); a carboxyl group (—CO.sub.2R.sup.18) a cyanate group (—OCN); an isocyano group (—NC); an isocyanate group (—NCO); a thiocyanate group (—SCN) or a thioisocyanate group (—NCS); an optionally substituted amino group; a hydroxy group; a nitro group; a CF.sub.3 group; a halo group (Cl, Br, F, I); —SR.sup.19; —SO.sub.3H; —SO.sub.2R.sup.20; —SF.sub.5; an optionally substituted silyl group; a C.sub.2-C.sub.10 alkynyl group substituted with a —SiH.sub.2R.sup.22 group, a C.sub.2-C.sub.10 alkynyl substituted with a —SiHR.sup.22R.sup.23 group, or a C.sub.2-C.sub.10 alkynyl moiety substituted with a —Si(R.sup.22).sub.x(R.sup.23).sub.y(R.sup.24).sub.z group; wherein each R.sup.22 group is independently selected from the group consisting of a branched or unbranched, substituted or unsubstituted C.sub.1-C.sub.10 alkyl group, a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.10 alkynyl group, a substituted or unsubstituted C.sub.2-C.sub.20 cycloalkyl group, a substituted or unsubstituted C.sub.2-C.sub.10 alkenyl group, and a substituted or unsubstituted C.sub.6-C.sub.20 cycloalkylalkylene group; each R.sup.23 group is independently selected from the group consisting of a branched or unbranched, substituted or unsubstituted C.sub.1-C.sub.10 alkyl group, a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.10 alkynyl group, a substituted or unsubstituted C.sub.2-C.sub.10 alkenyl group, a substituted or unsubstituted C.sub.2-C.sub.20 cycloalkyl group, and a substituted or unsubstituted C.sub.6-C.sub.20 cycloalkylalkylene group; R.sup.24 is independently selected from the group consisting of hydrogen, a branched or unbranched, substituted or unsubstituted C.sub.2-C.sub.10 alkynyl group, a substituted or unsubstituted C.sub.2-C.sub.20 cycloalkyl group, a substituted or unsubstituted C.sub.6-C.sub.20 cycloalkylalkylene group, a substituted C.sub.5-C.sub.20 aryl group, a substituted or unsubstituted C.sub.6-C.sub.20 arylalkylene group, an acetyl group, a substituted or unsubstituted C.sub.3-C.sub.20 heterocyclic ring comprising at least one of O, N, S and Se in the ring; wherein x=1 or 2; y=1 or 2; z=0 or 1; and (x+y+z)=3; wherein each of R.sup.15, R.sup.16, R.sup.18, R.sup.19 and R.sup.20 independently represent H or optionally substituted C.sub.1-C.sub.40 carbyl or hydrocarbyl group optionally comprising one or more heteroatoms; wherein R.sup.17 represents a halogen atom, H or optionally substituted C.sub.1-C.sub.40 carbyl or C.sub.1-C.sub.40 hydrocarbyl group optionally comprising one or more heteroatoms; wherein k and I are independently 1 or 2; 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 preferably at least one of Ar.sub.1, Ar.sub.2 and Ar.sub.3 is substituted with at least one polar or more polarising group; wherein X′ is a halogen atom or a cyclic borate group; and wherein Y′ is a halogen atom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a representation of top contact/bottom gate Organic Thin Film Transistor (OTFT)

(2) FIG. 2 is a representation of bottom contact/bottom gate OTFT

(3) FIG. 3 is a representation of top contact/top gate OTFT

(4) FIG. 4 is a representation of bottom contact/top gate OTFT

(5) Labels—A: Substrate; B: Gate electrode; C: Dielectric layer; D: Semiconductor layer; E: Source electrode; F: Gate electrode

(6) FIG. 5: Transfer characteristic for TG 10 micron channel length and 500 micron channel width OTFT using 1,4,8,11-tetramethyl bis-triethysilylethynyl pentacene and PAHC (1) described as Formulation (1). Drain voltage is −2V.

(7) FIG. 6: Transfer characteristic for TG 30 micron channel length, 500 micron channel width OTFT using 1,4,8,11-tetramethyl bis-triethysilylethynyl pentacene and PAHC (1) described as Formulation (1). Drain voltage is −2V.

(8) FIG. 7: Transfer characteristic for TG 30 micron channel length, 500 micron channel width OTFT using 1,4,8,11-tetramethyl bis-triethysilylethynyl pentacene and PAHC (3) described as Formulation (3). Drain voltage is −2V.

EXAMPLES OF THE PRESENT INVENTION

(9) The following examples of the present invention are merely exemplary and should not be viewed as limiting the scope of the invention.

(10) Measurement of the Capacitance of the Polymer Binder

(11) 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. 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 1×1 inch glass substrates.

(12) 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.

(13) After deposition of the polymer binder the substrate was annealed on a hotplate at 120° C. for 5 minutes.

(14) 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.

(15) 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.

(16) 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).
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 8.8854×10.sup.−12 F/m.

(17) As a reference sample, a polystyrene sample (Mw˜350,000) having a thickness of 1 μm 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.

(18) OTFT Fabrication Method

(19) 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 the 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.

(20) 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.

(21) 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 is set at −2V and the gate voltage scanned from +20V to −40V. Drain current is measured and mobility calculated from the transconductance.

(22) 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 (μ) 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):

(23) $\begin{array}{cc}S=\frac{\mu {\mathrm{WC}}_i{V}_{\mathrm{DS}}}{L}& \mathrm{Equation}1\end{array}$

(24) 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)

(25) $\begin{array}{cc}{I}_{\mathrm{DS}}\approx \frac{{\mathrm{WC}}_i{\mu \left(V_{\mathrm{GS}}-V_T\right)}^2}{2L}& \mathrm{Equation}2\end{array}$

(26) The following examples are intended to explain the invention without restricting it. The methods, structures and properties described herein can also be applied to materials that are claimed in this invention but not explicitly described in the examples.

Compound (1)

Preparation of 4-bromobenzene-1,2-dimethanol

(27) ##STR00021##

(28) A solution of lithium aluminium anhydride (Sigma-Aldrich 593702, 2M solution in THF, 100 mL, 200 mmol) in THF (Sigma-Aldrich 401757, 300 mL) was cooled in an ice-water bath. A solution of 4-bromophthalic anhydride (Fluorochem 009065, 45.40 g, 200 mmol) in THF (200 mL) was added dropwise over 4 hours. The reaction mixture was then allowed to stir for 6 hours. The ice-water bath was then removed and the mixture allowed to warm to room temperature overnight. The mixture was then cooled in an ice-water bath. Water (7.6 mL) was added dropwise. 15% NaOH solution (7.6 mL) was then added dropwise. A further quantity of water (22.8 mL) was added. The ice-water bath was removed and the reaction mixture allowed to stir for 1 hr. The mixture was then filtered and the filter cake washed with THF 3×200 mL). The filtrates were combined, dried over MgSO.sub.4, filtered and concentrated to give a pale yellow oil which solidified on standing (31.48 g). The crude product was purified by crystallisation from dichloromethane to give the product (1) as a colourless solid (23.50 g, 108 mmol, 54%). .sup.1H NMR (600 MHz, DMSO-d6) 10.52 (1H, s), 10.46 (1H, s), 8.11-8.10 (1H, m), 7.92-7.84 (2H, m).

Compound (2)

Preparation of 4-bromo-1,2-benzenedicarboxaldehyde

(29) ##STR00022##

(30) Oxalyl chloride (Sigma-Aldrich O8801, 24.0 g, 176 mmol) in dichloromethane (200 mL) was stirred at −78 deg C. A mixture of dimethylsulfoxide (29.92 g, 384 mmol) and dichloromethane (50 mL) was added dropwise over 60 minutes. A solution of 4-bromobenzene-1,2-dimethanol (1) (17.36 g, 80.0 mmol) in dichloromethane (10 mL) and dimethylsulfoxide (10 mL) was added dropwise over 30 minutes. The reaction mixture was stirred for 30 minutes. Triethylamine (Sigma-Aldrich T0886, 200 mL, 1438 mmol) was added over 80 minutes. The reaction mixture was then allowed to warm to room temperature with stirring overnight. Water (400 mL) was then added. The organic layer was separated and the aqueous layer extracted with dichloromethane (2×200 mL). The organic layers were combined, dried over MgSO.sub.4, filtered and concentrated in vacuo to give a pale orange solid (19.12 g). The material was purified by dry column chromatography (gradient elution:heptane: 10% ethyl actate:heptane) to give the product (2) as a pale brown solid (14.98 g, 70.3 mmol, 88%). .sup.1H NMR (600 MHz, CDCl.sub.3) 10.52 (1H, s), 10.46 (1H, s), 8.11-8.10 (1H, m), 7.92-7.84 (2H, m).

Compound (3)

2,9-dibromo-6,13-pentacenedione/2,10-dibromo-6,13-pentacenedione

(31) ##STR00023##

(32) 4-bromo-1,2-benzendicarboxaldehyde(2) (14.87 g, 698 mmol, 2 eq) and 1,4-cyclohexanedione (Aldrich 125423, 3.91 g, 349 mmol, 1 eq) were charged to a 2 L round bottom flask. Methylated spirits (74O.P., Fisher 11482874, 1000 mL) was added and the mixture stirred at room temperature. 5% sodium hydroxide solution (22.0 mL, 275 mmol) was then added. A dark brown precipitate formed rapidly. The reaction mixture was then heated to 60 deg C. and the mixture stirred at 60 deg C. for 1 h. The mixture was then cooled to ˜18 deg C. The solid was collected by filtration under suction. The filter cake was washed sequentially with water (200 mL), methylated spirits (74O.P., 400 mL) and diethyl ether (400 mL). The solid was then dried in a vacuum oven to give the product (3) as an orange/brown solid (13.56 g, 82%). MS (ASAP) m/z 466 (M.sup.+, 100%).

Compound (4)

2,9-dibromo-6,13-bis(triisopropylsilylacetylene)pentacenedione-2,10-dibromo-6,13-bis(triisoropvlsilylacetylene)pentacene

(33) ##STR00024##

(34) Triisopropylsilyl acetylene (Fluorochem S18000, 22.5 g, 100 mmol, 6.2 eq) was added dropwise to a solution of isopropylmagnesium chloride (2M in THF, Aldrich 230111, 50.25 mL, 100 mmol, 6.2 eq) in THF (Sigma-Aldrich 401757, 150 mL) at room temperature. The solution was then heated to 60 deg C. and stirred at this temperature for 45 minutes. The mixture was then cooled to 20 de C. 2,9-Dibromo-6,13-pentacenedione/2,10-dibromo-6,13-pentacenedione(3) (7.50 g, 16.1 mmol, 1 eq) was then added and the reaction mixture heated to 60 deg C. and stirred overnight. The reaction mixture was then cooled to 20 deg C. A solution of tin (II) chloride dihydrate (Sigma-Aldrich 208256, 36.30 g) in 10% HCl (165 mL) was added dropwise. The reaction mixture was then heated to 50 deg C. and stirred for 1 hr. The reaction mixture was then cooled to <10 deg C. and the solid collected by filtration. The filter cake was washed with acetone (2×100 mL) to give a grey solid (6.58 g). The solid was then purified by flash column chromatography (gradient elution:heptane; 10%-50% DCM:heptane) to give two crops; the first crop was then dissolved in DCM (50 mL), acetone (200 mL) was added and the product (4) collected by filtration (2.15 g). The second crop was purified by flash column chromatography and precipitation as described above to give the product (4) as a blue solid (1.70 g; total mass=3.85 g, 4.27 mmol, 27%). .sup.1H NMR (500MHz, CDCl.sub.3) 9.26 (2H, s), 9.25 (2H, s), 9.19 (2H, s), 9.17 (2H, s), 8.13 (4H, s), 7.83 (4H, d, J=9.1 Hz), 7.45 (4H, d, J=9.1 Hz), 1.46-1.35 (84H, m).

Compound (5)

Preparation of N,N-diphenyl-2,4-dimethylphenylamine

(35) ##STR00025##

(36) Diphenylamine (Sigma-Aldrich 242586, 36.50 g, 216 mmol, 1 eq), 4-iodo-m-xylene (Fluorochem 001771, 100.11 g, 431 mmol, 2 eq), 1,10-phenanthroline (Sigma-Aldrich 131377, 7.77 g, 43.1 mmol, 0.2 eq) and o-xylene (Sigma-Aldrich 95662, 150 mL) were charged to a round bottom flask. The reaction mixture was heated to 120 deg C. After 1 hour copper (I) chloride (Sigma-Aldrich 212946, 4.27 g, 43.1 mmol, 0.2 eq) and KOH (Sigma-Aldrich 484016, 96.82 g, 1726 mmol, 4 eq) were added and the reaction mixture heated to 160 deg C. and stirred overnight. The mixture was allowed to cool and DCM (200 mL) was added. The mixture was then filtered through a pad of celite. Water (200 mL) was added to the filtrate, the layers were separated and the organic phase washed with water (200 mL). The aqueous phases were back-extracted with DCM (200 mL) and the combine organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a viscous dark brown-black oil (72.43 g). The crude product was purified by dry column chromatography (eluent heptane) (55.10 g) followed by recrystallization from methanol to give the product (5) as a colourless crystalline solid (45.56 g, 84%). .sup.1H NMR (500MHz, CDCl.sub.3) 7.25-6.88 (13H, m), 2.35 (3H, s), 2.02 (3H, s).

Compound (6)

Preparation of N,N-bis(4-bromophenyl)-2,4-dimethylphenylamine

(37) ##STR00026##

(38) A solution N,N-diphenyl-2,4-dimethylphenylamine (40.00, 146 mmol, 1 eq) in DMF (200 mL) was cooled to −60 deg C. A solution of N-bromosuccinimide (Sigma-Aldrich B81255, 52.08 g, 293 mmol, 2 eq) in DMF (260 mL) was added over 30 minutes, then the mixture was allowed to warm to room temperature. After 2 hours the reaction mixture was poured into water (2.4 L). The mixture was extracted with heptane (4×800 mL), the organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a colourless solid (61.92 g). The product was recrystallized from methanol/acetone (1:1 mixture) to give the product (6) as a colourless crystalline solid (57.13 g, 91%). .sup.1H NMR (500 MHz, CDCl.sub.3) 7.28 (4H, d, J=8.8 Hz), 7.07-6.95 (3H, m), 6.82 (4H, d, J=8.8 Hz), 2.34 (3H, s), 1.98 (3H, s).

Compound (7)

Preparation of N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-2,4-dimethylphenylamine

(39) ##STR00027##

(40) A stirred solution of N,N-bis(4-bromophenyl)-2,4-dimethylphenylamine (6) (10.00 g, 23.2 mmol, 1 eq) in THF (Sigma-Aldrich 401757, 40 mL) under nitrogen was cooled to −65 deg C. n-Butyllithium (Acros 10181852, 2.5M solution in hexanes, 22.3 mL, 55.7 mmol, 2.4 eq) was added dropwise and the reaction mixture was then stirred for 1 h. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (Sigma-Aldrich 417149, 11.22 g, 60.3 mmol, 2.6 eq) was added dropwise. The reaction mixture was then allowed to warm to room temperature overnight Water (60 mL) was added and the mixture stirred for 20 minutes. The mixture was then extracted with dichloromethane (3×60 mL). The combined organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a yellow foam (11.27 g). The product was then purified by dry column chromatography (gradient elution 5%-10% EtOAc:heptane) to give a colourless solid (6.65 g). This was recrystallized from MeCN/THF to give the product (7) as a colourless crystalline solid (6.14 g, 11.7 mmol, 50%). .sup.1H NMR (500MHz, CDCl.sub.3) 7.63 (4H, d, J=8.3 Hz), 7.06-6.99 (3H, m), 6.96 (4H, d, J=8.3 Hz), 2.34 (3H, s), 1.96 (3H, s), 1.32 (24H, s). MS (ASAP) m/z 525 (M.sup.+, 100%).

Compound (8)

Preparation of N,N-diphenyl-4-methoxyphenylamine

(41) ##STR00028##

(42) Diphenylamine (Sigma-Aldrich 242586, 36.50 g, 216 mmol, 1 eq), 4-iodoanisole (Sigma-Aldrich 17608, 100.96 g, 431 mmol, 2 eq), 1,10-phenanthroline (Sigma-Aldrich 131377, 7.77 g, 43.1 mmol, 0.2 eq) and xylene (150 mL) were charged to a round bottom flask. The reaction mixture was heated to 120 deg C. After 1 hour copper (I) chloride (Sigma-Aldrich 212946, 4.27 g, 43.1 mmol, 0.2 eq) and KOH (Sigma-Aldrich 484016, 96.82 g, 1726 mmol, 4 eq) were added and the reaction mixture heated to 160 deg C. and stirred overnight. The mixture was allowed to cool, then water (250 mL) and DCM (200 mL) were then added. The mixture was then filtered through a pad of celite. The mixture was separated and the organic phase washed with water (200 mL). The aqueous phases were back-extracted with DCM (200 mL) and the combine organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a viscous dark brown-black oil (80.20 g). The crude product was purified by dry column chromatography (gradient elution:heptane, 5-10% DCM:heptane) followed by recrystallization from methanol to give the product (8) as a colourless crystalline solid (52.60 g, 89%). .sup.1H NMR (500MHz, CDCl.sub.3) 7.25-6.82 (14H, m), 3.81 (3H, s, OCH.sub.3).

Compound (9)

Preparation of N,N-bis(4-bromophenyl)-4-methoxyphenylamine

(43) ##STR00029##

(44) A solution of N,N-diphenyl-4-methoxyphenylamine (8) (40.00, 146 mmol, 1 eq) in DMF (240 mL) was cooled to −60 deg C. A solution of N-bromosuccinimide (51.71 g, 291 mmol, 2 eq) in DMF (260 mL) was added over 30 minutes, then the mixture was allowed to warm to room temperature. After 2 hours the reaction mixture was poured into water (2.4 L). The mixture was extracted with heptane (4×800 mL), the organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a brown oil (65.12). The product was purified by dry column chromatography (eluent heptane) to give the product as a colourless solid (52.36 g, 52%). .sup.1H NMR (500MHz, CDCl.sub.3) 7.30 (4H, d, J=8.7 Hz), 7.02 (2H, d, J=8.7 Hz), 6.8 (4H, d, J=8.7 Hz), 6.84 (2H, d, J=8.7 Hz), 3.80 (3H, s, OCH.sub.3).

Compound (10)

Preparation of N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4-phenylamine

(45) ##STR00030##

(46) A stirred solution of N,N-bis(4-bromophenyl)-4-methoxyphenylamine (9) (15.00 g, 34.6 mmol, 1 eq) in THF (Sigma-Aldrich 401757, 60 mL) under nitrogen was cooled to −65 deg C. n-Butyllithium (Acros 213358000, 2.5M solution in hexanes, 33.2 mL, 2.4 eq) was added dropwise and the reaction mixture was then stirred for 1 h. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (Sigma-Aldrich 417149, 16.75 g, 90.0 mmol, 2.6 eq) was added dropwise. The reaction mixture was then allowed to warm to room temperature overnight. Water (90 mL) was added and the mixture stirred for 20 minutes. The mixture was then extracted with dichloromethane (5×90 mL). The combined organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a yellow foam (16.01 g). The product was then purified by dry column chromatography (gradient elution 5%-15% EtOAc:heptane) to give the product as colourless solid (7.31 g, 13.9 mmol, 40%). .sup.1H NMR (500MHz, CDCl.sub.3) 7.66 (4H, d, J=6.8 Hz), 7.06 (2H, d, J=8.9 Hz), 7.02 (4H, d, J=6.8 Hz), 3.81 (3H, s, OCH.sub.3), 1.33 (24H, s).

Compound (11)

Preparation of bis(N-4-chlorophenyl)-2,4-dimethoxyphenylamine

(47) ##STR00031##

(48) 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), 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 minutes. 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 mL×2) and the combined aqueous layers back-extracted with DCM (200 mL×2). The organic layers were combined, dried over MgSO.sub.4 (30 minutes) and filtered. The filter cake was washed with further DCM (150 mL×2) and the combined filtrates concentrated invacuo 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 recystallised from heptane to give a colourless crystalline solid (11) (62.89 g, 43%). .sup.1H NMR (500MHz) 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)

Compound (12)

Preparation of N,N-diphenyl-2,4-dimethoxyphenylamine

(49) ##STR00032##

(50) A solution of N,N-bis(4-chlorophenyl)-2,4-dimethoxyphenylamine (10.0 g, 26.7 mmol, 1 eq) in toluene (100 mL) was stirred at room temperature under N.sub.2. Ammonium formate (Sigma-Aldrich 156264, 20 g, 317 mmol) and 10% Pd on activated charcoal (Sigma-Aldrich 75993, 50% water content, 5.0 g) was added and the mixture heated to 65 deg C. overnight. A further portion of ammonium formate (30 g, 476 mmol) and 10% Pd on C (5 g) were added and the mixture stirred at 65 deg C. for 2 h. The reaction mixture was allowed to cool and then filtered (Whatman GF/F filter) under suction using a Buchner funnel. The filtrate was then washed with water. The organic layer was then dried over MgSO.sub.4, filtered and concentrated to give the product (12) as colourless solid (8.16 g, 100%). .sup.1H NMR (500MHz, CDCl.sub.3) 7.20-6.90 (10H, m), 6.55-6.48 (3H, m), 3.83 (3H, s), 3.65 (3H, s).

Compound (13)

Preparation of N,N-bis(4-bromophenyl)-2,4-dimethoxyphenylamine

(51) ##STR00033##

(52) A solution of N,N-diphenyl-2,4-dimethoxyphenylamine(12) (8.00 g, 26.2 mmol, 1 eq) in DMF (Sigma-Aldrich 227056, 140 mL) was stirred at −60 deg C. under N.sub.2. A solution of N-bromosuccinimide (Sigma-Aldrich B81255, 9.50 g, 53.4 mmol, 2 eq) was added dropwise. The mixture was then allowed to warm to room temperature. After 2 h the reaction mixture was then poured into a stirred mixture of water (1 L) and heptane (500 mL). The organic layer was separated and the aqueous extracted with heptane (3×500 mL) The heptane extracts were washed with water (500 mL), dried over MgSO.sub.4, filtered and concentrated in vacuo to give a red-orange solid (9.40 g). The product was purified by dry column chromatography (gradient elution:heptane; 5%-20% DCM:heptane) to give the product as a colourless solid (9.28 g, 76%). .sup.1H NMR (300MHz, CDCl.sub.3) 7.28 (4H, d, J=6.0 Hz), 7.06-7.04 (1H, m), 6.86 (4H, d, J=6.0 Hz), 6.55-6.48 (2H, m), 3.85 (3H, s), 3.66 (3H, s).

Compound (14)

Preparation of N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-2,4-methoxyphenylamine

(53) ##STR00034##

(54) A solution of N,N-bis(4-bromophenyl)-2,4-dimethoxyphenylamine(13) (6.00 g, 13.0 mmol, 1 eq) in THF (Sigma-Aldrich 401757, 30 mL) under N.sub.2 was cooled to −70 deg C. n-Butyllithium (Acros 213358000, 2.5M in hexanes, 14.1 mL, 35.3 mmol, 2.7 eq) was added dropwise and the mixture stirred for 1 h. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (Sigma-Aldrich 417149, 6.80 g, 36.5 mmol, 2.8 eq) was added dropwise. The reaction mixture was then allowed to warm to room temperature with stirring overnight. Water (40 mL) was then added, the organic layer was separated and the aqueous layer extracted with DCM (5×40 mL). The combined organic extracts were dried over MgSO.sub.4, filtered and concentrated in vacuo to give a yellow oil (7.30 g). The product was purified by dry column chromatography (gradient elution:heptane; 5%-15% EtOAc:heptane) to give the product (14) as a colourless solid (2.81 g, 5.0 mmol, 39%). .sup.1H NMR (300 MHz, CDCl.sub.3) 7.63 (4H, d, J=8.6 Hz), 7.07-7.04 (1H, m), 6.97 (4H, d, J=8.6 Hz), 6.54-6.46 (2H, m), 3.82 (3H, s), 3.60 (3H, s).

PAHC Copolymer (1)

Preparation of TIPS pentacene-2,4-dimethyltriarylamine copolymer

(55) A mixture of 2,9-dibromo-6,13-bis(triisopropylsilylacetylene)pentacenedione/2,10-dibromo-6,13-bis(triisopropylsilylacetylene)pentacene(4) (0.39 g, 0.49 mmol, 0.5 eq), N,N-bis(4-bromophenyl)-2,4-dimethylphenylamine(6) (0.21 g, 0.49 mmol, 0.5 eq) N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-2,4-dimethylphenylamine(7) (0.52 g, 0.98 mmol, 1 eq) tetrakis(triphenylphosphine)palladium (0) (Acros 12065360, 0.034 g, 0.03 mmol, 0.03 eq), 2M K.sub.2CO.sub.3 (2.9 mL, 5.88 mmol, 6 eq) and Aliquat® 336 (Sigma-Aldrich 205613, 6 drops) in toluene (42 mL) was degassed by passing a stream of nitrogen through the solution for 30 minutes. The mixture was then heated to reflux. After 1 hour HPLC confirmed the presence of oligomers. The reaction mixture was allowed to cool to 50 deg C. The reaction mixture was poured into MeOH (135 mL) with stirring. After 30 minutes the precipitated solid was collected by filtration under suction using a Buchner funnel to give a brown powder (1.20 g). The solid was purified by flash column chromatography (eluent: toluene). The fractions containing the product were concentrated in vacuo to give a dark purple solid (0.45 g). The solid was slurried in methanol (5 mL) and the solid collected by filtration under suction using a Buchner funnel. The solid was then dried in a vacuum oven to give the product as a dark purple solid (0.32 g)(75% 2,4-dimethyltriarylamine:25% TIPS pentacene) which was characterised as follows: GPC Mn=5033 Daltons, N.sub.av=14.

(56) Permittivity of the TIPS pentacene-2,4-dimethyltriarylamine copolymer (1) was 2.96.

(57) (As a comparison, the permittivity of commercially available 2,4-dimethylpolytriarylamine (High Force Research Ltd Code for the 2,4-dimethyl polytriarylamine polymer, PE3) purchased from High Force Research Ltd was measured, in our permittivity tests the binder PE3 had a permittivity of 2.98).

(58) Formulation 1

(59) TIPS pentacene-2,4-dimethyltriarylamine copolymer, PAHC (1) and polyacene 1, (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (70:30 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 1.7 wt. % total solids. This was coated as an organic semiconductor layer in an OTFT according to the method described above. The formulation was 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.

(60) Mobility in the OTFT was 1.1 cm.sup.2V.sup.−1s.sup.−1 at channel length L=4 μm, (linear mobility).

(61) Mobility in the TFT was 2.2 cm.sup.2V.sup.−1s.sup.−1 at channel length L=30 μm, (linear mobility).

PAHC Copolymer (2)

Preparation of TIPS pentacene-4-methoxytriarylamine Copolymer

(62) A mixture of 2,9-dibromo-6,13-bis(triisopropylsilylacetylene)pentacenedione/2,10-dibromo-6,13-bis(triisopropylsilylacetylene)pentacene(4) (0.39 g, 0.49 mmol, 0.5 eq), N,N-bis(4-bromophenyl)-4-methoxyphenylamine(9) (0.21 g, 0.49 mmol, 0.5 eq) N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4-methoxyphenylamine(10) (0.52 g, 0.98 mmol, 1 eq) tetrakis(triphenylphosphine)palladium (0) (Acros 12065360, 0.034 g, 0.03 mmol, 0.03 eq), 2M K.sub.2CO.sub.3 (2.9 mL, 5.88 mmol, 6 eq) and Aliquat® 336 (6 drops) in toluene (42 mL) was degassed by passing a stream of nitrogen through the solution for 30 minutes. The mixture was then heated to reflux. After 30 minutesHPLC confirmed the presence of oligomers. The reaction mixture was allowed to cool to 50 deg C. The reaction mixture was poured into MeOH (135 mL) with stirring. After 30 minutes the precipitated solid was collected by filtration under suction using a Buchner funnel to give a brown powder (0.67 g). The solid was purified by flash column chromatography (eluent THF). The fractions containing the product were concentrated in vacuo to give a dark purple solid (0.67 g). The solid was dissolved in THF (10 mL) and poured into methanol (30 mL). The precipitated solid was collected by filtration under suction using a Buchner funnel. The solid obtained was then dried in a vacuum oven to give the product as a dark green powder (0.59 g)(75% 4-methoxytriarylamine: 25% TIPS pentacene) which was characterised as follows: GPC Mn=4680 Daltons, N.sub.av=13.

(63) Permittivity of the TIPS pentacene-4-methoxytriarylamine copolymer (2) was 3.26.

(64) Formulation 2

(65) TIPS pentacene-2,4-dimethoxytriarylamine copolymer, PAHC (2) and polyacene 1, (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (70:30 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 1.7 wt. % total solids. This was coated as an organic semiconductor layer in an OTFT according to the method described above. The formulation was 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.

(66) Mobility in the OTFT was 0.98 cm.sup.2V.sup.−1s.sup.−1 at channel length L=30 μm, (linear mobility).

PAHC Copolymer (3)

Preparation of TIPS pentacene-2,4-dimethoxytriarylamine copolymer

(67) A mixture of 2,9-dibromo-6,13-bis(triisopropylsilylacetylene)pentacenedione/2,10-dibromo-6,13-bis(triisopropylsilylacetylene)pentacene(4) (0.43 g, 0.54 mmol, 0.5 eq), N,N-bis(4-bromophenyl)-2,4-dimethoxyphenylamine(13) (0.25 g, 0.54 mmol, 0.5 eq) N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-2,4-dimethoxyphenylamine(14) (0.60 g, 1.08 mmol, 1 eq) tetrakis(triphenylphosphine)palladium (0) (Acros 12065360, 0.037 g, 0.03 mmol, 0.03 eq), 2M K.sub.2CO.sub.3 (3.2 mL, 6.48 mmol, 6 eq) and Aliquat® 336 (7 drops) in toluene (50 mL) was degassed by passing a stream of nitrogen through the solution for 30 minutes. The mixture was then heated to reflux. After 30 minutes HPLC confirmed the presence of oligomers. The reaction mixture was allowed to cool to 50 deg C. The reaction mixture was poured into MeOH (150 mL) with stirring. After 30 minutes the precipitated solid was collected by filtration under suction using a Buchner funnel to give a brown powder (0.87 g). The solid was purified by flash column chromatography (eluent: THF). The fractions containing the product were concentrated in vacuo to give a dark purple solid (0.73 g). The solid was purified again by flash column chromatography (eluent THF). The fractions containing the product were concentrated in vacuo to give a dark purple solid (0.47 g). The solid was dissolved in THF (10 mL) and poured into methanol (30 mL). The precipitated solid was collected by filtration under suction using a Buchner funnel. The solid obtained was then dried in a vacuum oven to give the product as a dark green powder (0.45 g) (75% 2,4-dimethoxytriarylamine:25% TIPS pentacene) which was characterised as follows: GPC Mn=5079 Daltons, N.sub.AV=13.

(68) Permittivity of the TIPS pentacene-4-methoxytriarylamine copolymer (3) was 3.10.

(69) Formulation 3

(70) TIPS pentacene-2,4-dimethoxytriarylamine copolymer, PAHC (3) and polyacene 1, (1,4,8,11-tetramethyl-6,13-bis(triethylsilylethynyl)pentacene) (70:30 ratio by weight) were dissolved in 1,2,3,4-tetrahydronaphthalene at 1.7 wt. % total solids. This was coated as an organic semiconductor layer in an OTFT according to the method described above. The formulation was 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.

(71) Mobility was 0.7 cm.sup.2V.sup.−1s.sup.−1 (linear mobility, at channel length 10=μm).

(72) Mobility in the OTFT was 1.4 cm.sup.2V.sup.−1s.sup.−1 at channel length 30=μm, (linear mobility).

(73) Particularly preferred PAHCs according to the present invention are shown in the following table:

(74) TABLE-US-00002 Preferred PAHCs Case 1 R′.sup.a, R′.sup.b, R′.sup.c, R′.sup.d, R′.sup.e = H R.sup.6 = R.sup.13 = trimethylsilyl ethynyl; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, and R.sup.14 = H; and R.sup.3 and, R.sup.9 are bonds to another unit of Monomer (A) or (B) Case 2 R.sup.6 = R.sup.13 = triisopropyllsilylethynyl Case 3 Case 4 R.sup.6 = R.sup.13 = triisopropyllsilylethynyl; and R.sup.1, R.sup.4, R.sup.8, R.sup.11 = C.sub.1 to C.sub.4 alkyl (e.g. methyl) Case 5 R.sup.6 = R.sup.13 = triisopropylsilylethynyl; and R.sup.1, R.sup.4, R.sup.8, R.sup.11 = C.sub.1 to C.sub.4 alkoxy (e.g. methoxy) Case 6 R.sup.6 = R.sup.13 = triethylsilylethynyl Case 7 Case 1 R′.sup.b, R′.sup.d, R′.sup.e = H Case 2 Case 3 R′.sup.a and R′.sup.c = C.sub.1 to C.sub.4 alkyl Case 4 Case 5 Case 6 Case 7 Case 1 R′.sup.b, R′.sup.c, R′.sup.d, R.sup.′e = H Case 2 R′.sup.a = C.sub.1 to C.sub.6 alkoxy Case 3 (i) R′.sup.a = methoxy Case 4 (ii) R′.sup.a = ethoxy Case 5 Case 6 Case 7 Case 1 R′.sup.a, R′.sup.b, R′.sup.d, R′.sup.e = H Case 2 R′.sup.c = C.sub.1 to C.sub.6 alkoxy Case 3 (i) R′.sup.c = methoxy Case 4 (ii) R′.sup.c = ethoxy Case 5 Case 6 Case 7 Case 1 R′.sup.a, R′.sup.b, R′.sup.c, R′.sup.d = H Case 2 R′.sup.e = C.sub.1 to C.sub.6 alkoxy Case 3 (i) R′.sup.e = methoxy Case 4 (ii) R′.sup.e = ethoxy Case 5 Case 6 Case 7 Case 1 R′.sup.b, R′.sup.d, R′.sup.e = H Case 2 R′.sup.a = R′.sup.c = C.sub.1 to C.sub.6 alkoxy Case 3 (i) R′.sup.a = R′.sup.c = methoxy Case 4 (ii) R′.sup.a = R′.sup.c = ethoxy Case 5 Case 6 Case 7 Case 1 R′.sup.b, R′.sup.d = H Case 2 R′.sup.a, R′.sup.c, R′.sup.e = C.sub.1 to C.sub.6 alkoxy Case 3 (i) R′.sup.a, R′.sup.c, R′.sup.e = Case 4 methoxy Case 5 (ii) R′.sup.a, R′.sup.c, R′.sup.e = ethoxy Case 6 Case 7 Case 1 R′.sup.b, R′.sup.d = H Case 2 R′.sup.b, R′.sup.c, R′.sup.d = C.sub.1 to C.sub.6 alkoxy Case 3 (i) R′.sup.b, R′.sup.c, R′.sup.d = methoxy Case 4 (ii) R′.sup.b, R′.sup.c, R′.sup.d = ethoxy Case 5 Case 6 Case 7 Case 1 R′.sup.b, R′.sup.c, R′.sup.d, R′.sup.e = H Case 2 R′.sup.a = Cyano (CN) Case 3 Case 4 Case 5 Case 6 Case 7 Case 1 R′.sup.b, R′.sup.c, R′.sup.d, R′.sup.e = H Case 2 R′.sup.a = Isopropylcyano group Case 3 Case 4 Case 5 Case 6 Case 7 Case 1 R′.sup.a, R′.sup.b, R′.sup.d, R′.sup.e = H Case 2 R′.sup.c = Isopropylcyano group Case 3 Case 4 Case 5 Case 6 Case 7 0

(75) The organic semiconductors compounds specified in the table are particularly preferred as they combine the beneficial properties of high charge transport mobility (of the binders) with a polarity that is more compatible with benign, non-chlorinated solvents that will be desirable for use in large area printing. In addition, as these compounds are more polar once deposited as the OSC layer, or alternatively as a component in the OSC layer, they are expected to be resistant to being re-dissolved by the hydrophobic solvents used for the organic gate insulators (OGI) such as Cytop. Furthermore, it is expected that the polar binders are useful for both top gate and bottom gate OTFTs, particularly for bottom gate OTFTs.