WO2014205512A1

WO2014205512A1 - Novel polymers and their use in organic photovoltaics

Info

Publication number: WO2014205512A1
Application number: PCT/AU2014/050084
Authority: WO
Inventors: Ming Chen; Mei Gao; Scott Watkins; Jegadesan Subbiah; Wallace WONG; Balaji Purushothaman; David Jones; Andrew Holmes
Original assignee: The University Of Melbourne; Commonwealth Scientific And Industrial Research Organisation
Priority date: 2013-06-25
Filing date: 2014-06-20
Publication date: 2014-12-31

Abstract

High molar mass electron donor (p-type) conjugated polymers are described. The polymers comprise donor groups based upon benzodithiophene units together with various heterocyclic aromatic acceptor components and find particular use in bulk heterojunction devices such as solar cells.

Description

NOVEL POLYMERS AND THEIR USE IN ORGANIC PHOTOVOLTAICS

FIELD

[0001] High molar mass electron donor (p-type) conjugated polymers are disclosed. The polymers find particular use in bulk heterojunction devices.

BACKGROUND

[0002] Organic bulk heterojunction cells employ a blended combination of a p- type donor material and an n-type acceptor material (most commonly a fullerene derivative such as PC₆i BM or PC₇₁ BM or the analogous bis-indene adducts of C₆o or C70 respectively). Charge separation is facilitated by migration of an exciton (formed by photoexcitation) to the heterojunction. Charge separation is promoted by the offset in levels of the HOMO of the p-type material and the LUMO of the electron acceptor. For donor materials blended with fullerene derivatives, the HOMO-LUMO gap should be in the range of 1 .5 to 1 .8 eV and the HOMO energy level should be low (-5.2 to -5.8 eV). The LUMO energy level of the donor should be 0.2 eV above the LUMO level of the acceptor to promote negative charge migration to the acceptor after photoexcitation. These concepts have been fully described in the publications by C. J. Brabec et al., Adv. Mater., 2010, 22, 3839; G. Dennler, M. C. Scharber and C. J. Brabec, Adv. Mater. 2009, 21 , 1323 (for donor polymers) and A. Mishra and P. Baeuerle, Angew. Chem. Int. Ed., 2012, 51 , 2020 (for small molecules).

[0003] Bulk heterojunction solar cell energy conversion efficiencies in a single junction device have now been reported to reach ca.10% efficiency under standard AM1 .5 conditions with 1 sun irradiation (100 mW cm^"2). Efficiencies are determined by open circuit voltage \ _oc (ideally reaching up to or > 1 V), short circuit current J_sc (ideally in excess of 13 mA cm^"2) and fill factor FF (ideally in excess of 65%). Features that are known to contribute to improving these factors include (i) offset of the energy of the HOMO of the donor and the LUMO of the acceptor (allowing for a 0.3 eV energy difference to promote charge separation at the heterojunction); (ii) low HOMO-LUMO energy gap of the donor material to maximise photon absorption in the 800 nm region corresponding to the wavelength of maximum photon solar emission; (iii) ideal exciton diffusion length of about 10 nm which is largely determined by feature sizes and the morphology of the blend of donor and acceptor materials; (iv) balanced charge mobilities in the donor and acceptor materials; (v) high number average molar mass (for polymers) of the donor materials. [0004] Recently it has become apparent that the combination of donor and acceptor type building blocks in well-defined polymers can lead to donor p-type materials having the preferred low HOMO-LUMO gap corresponding to a long wavelength absorption maximum ideal for solar energy. A privileged donor building block is based on the benzodithiophene unit carrying "orthogonal" (for molecular stacking) thiophene substituents with long chain alkyl substituents (L. Huo, S. Zhang, X. Guo, F. Xu, Y. Li, J. Hou, Angew. Chem. Int. Ed., 201 1 , 50, 9697).

[0005] A combination of a benzodithiophene unit with an accepting unit (PBDT- T₈-TPD) was recently disclosed by Ma et al. (SCHEME 1 ).(J. Yuan, Z. Zhai, H. Dong, J. Li, Z. Jiang, Y. Li and W. Ma, Adv. Fund. Mater., 2013, 23, 885) This disclosure demonstrated a donor polymer with a HOMO-LUMO gap of 1 .8 eV and a high HOMO energy level of -5.61 eV leading to a bulk heterojunction solar cell device with a fullerene that exhibited an open circuit voltage of 1 V. In the device configuration ITO/PEDOT:PSS/PBDT-T₈-TPD:PC₆i BM (1 :1 )/LiF/AI the following parameters were measured: J_sc 9.79 mA cm^"2; V_∞ 1 V; FF 63%; PCE 6.2% (J. Yuan, Z. Zhai, H. Dong, J. Li, Z. Jiang, Y. Li and W. Ma, Adv. Fund. Mater., 2013, 23, 885).

SCHEME 1 : (PBDT_e-TPD)

[0006] While advances in polymeric materials continue to be made there remains a need to provide new polymers that may afford improved efficiencies in bulk heterojunction devices. SUMMARY

[0007] In one aspect there is provided a polymer of formula (1 ) comprising donor and acceptor components, wherein the donor component is represented by the formula (2)

wherein to R₈ are independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted aryl, and optionally substituted heterocyclyl; and

wherein the acceptor component is selected from one or more of the following structures 3 to 23;

CF, C-CF₃, C-CN, C-CI, N,

, C-COOR, C-CONHR

R = alkyl, aryl

[0008] In formula (1 ), 'n' may be in the range 30<n<1000, or may be in the range

50<n<200.

[0009] Alternatively or additionally, Ri to R₈ may be independently selected from alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heterocyclyl, heteroaryl, acyl, aralkyi, alkaryl, alkheterocyclyl, alkheteroaryl, alkcarbocyclyl, halo, haloalkyi, haloalkenyl, haloalkynyl, haloaryl, halocarbocyclyl, haloheterocyclyl, haloheteroaryl, haloacyl, haloaryalkyl, hydroxy, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, hydroxycarbocyclyl, hydroxyaryl, hydroxyheterocyclyl, hydroxyheteroaryl, hydroxyacyl, hydroxyaralkyl, alkoxyalkyl, alkoxyalkenyl, alkoxyalkynyl, alkoxycarbocyclyl, alkoxyaryl, alkoxyheterocyclyl, alkoxyheteroaryl, alkoxyacyl, alkoxyaralkyl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, carbocyclyloxy, aralkyloxy, heteroaryloxy, heterocyclyloxy, acyloxy, haloalkoxy, haloalkenyloxy, haloalkynyloxy, haloaryloxy, halocarbocyclyloxy, haloaralkyloxy, haloheteroaryloxy, haloheterocyclyloxy, haloacyloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, nitroheteroayl, nitrocarbocyclyl, nitroacyl, nitroaralkyl, amino (NH₂), alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, aralkylamino, diaralkylamino, acylamino, diacylamino, heterocyclamino, heteroarylamino, carboxy, carboxyester, amido, alkylsulphonyloxy, arylsulphenyloxy, alkylsulphenyl, arylsulphenyl, thio, alkylthio, alkenylthio, alkynylthio, arylthio, aralkylthio, carbocyclylthio, heterocyclylthio, heteroarylthio, acylthio, sulfoxide, sulfonyl, sulfonamide, aminoalkyl, aminoalkenyl, aminoalkynyl, aminocarbocyclyl, aminoaryl, aminoheterocyclyl, aminoheteroaryl, aminoacyl, aminoaralkyl, thioalkyl, thioalkenyl, thioalkynyl, thiocarbocyclyl, thioaryl, thioheterocyclyl, thioheteroaryl, thioacyl, thioaralkyl, carboxyalkyl, carboxyalkenyl, carboxyalkynyl, carboxycarbocyclyl, carboxyaryl, carboxyheterocyclyl, carboxyheteroaryl, carboxyacyl, carboxyaralkyl, carboxyesteralkyl, carboxyesteralkenyl, carboxyesteralkynyl, carboxyestercarbocyclyl, carboxyesteraryl, carboxyesterheterocyclyl , carboxyesterheteroaryl , carboxyesteracyl , carboxyesteraralkyl, amidoalkyl, amidoalkenyl, amidoalkynyl, amidocarbocyclyl, amidoaryl, amidoheterocyclyl, amidoheteroaryl, amidoacyl, amidoaralkyl, formylalkyl, formylalkenyl, formylalkynyl, formylcarbocyclyl, formylaryl, formylheterocyclyl, formylheteroaryl, formylacyl, formylaralkyl, acylalkyl, acylalkenyl, acylalkynyl, acylcarbocyclyl, acylaryl, acylheterocyclyl, acylheteroaryl, acylacyl, acylaralkyl, sulfoxidealkyl, sulfoxidealkenyl, sulfoxidealkynyl, sulfoxidecarbocyclyl, sulfoxidearyl, sulfoxideheterocyclyl, sulfoxideheteroaryl, sulfoxideacyl, sulfoxidearalkyl, sulfonylalkyl, sulfonylalkenyl, sulfonylalkynyl, sulfonylcarbocyclyl, sulfonylaryl, sulfonylheterocyclyl, sulfonylheteroaryl, sulfonylacyl, sulfonylaralkyl, sulfonamidoalkyl, sulfonamidoalkenyl, sulfonamidoalkynyl, sulfonamidocarbocyclyl, sulfonamidoaryl, sulfonamidoheterocyclyl, sulfonamidoheteroaryl, sulfonamidoacyl, sulfonamidoaralkyi, nitroalkyl, nitroalkenyl, nitroalkynyl, nitrocarbocyclyl, nitroaryl, nitroheterocyclyl, nitroheteroaryl, nitroacyl, nitroaralkyl, cyano, sulfate and phosphate groups.

[00010] In structures 3 to 23 one or more unsubstituted ring atoms, when present, may be optionally substituted with optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted aryl, and optionally substituted heterocyclyl. Alternatively or additionally, the one or more unsubstituted ring atoms in structures 3 to 23, when present, may be independently selected from alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heterocyclyl, heteroaryl, acyl, aralkyl, alkaryl, alkheterocyclyl, alkheteroaryl, alkcarbocyclyl, halo, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, halocarbocyclyl, haloheterocyclyl, haloheteroaryl, haloacyl, haloaryalkyl, hydroxy, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, hydroxycarbocyclyl, hydroxyaryl, hydroxyheterocyclyl, hydroxyheteroaryl, hydroxyacyl, hydroxyaralkyl, alkoxyalkyl, alkoxyalkenyl, alkoxyalkynyl, alkoxycarbocyclyl, alkoxyaryl, alkoxyheterocyclyl, alkoxyheteroaryl, alkoxyacyl, alkoxyaralkyl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, carbocyclyloxy, aralkyloxy, heteroaryloxy, heterocyclyloxy, acyloxy, haloalkoxy, haloalkenyloxy, haloalkynyloxy, haloaryloxy, halocarbocyclyloxy, haloaralkyloxy, haloheteroaryloxy, haloheterocyclyloxy, haloacyloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, nitroheteroayl, nitrocarbocyclyl, nitroacyl, nitroaralkyl, amino (NH2), alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, aralkylamino, diaralkylamino, acylamino, diacylamino, heterocyclamino, heteroarylamino, carboxy, carboxyester, amido, alkylsulphonyloxy, arylsulphenyloxy, alkylsulphenyl, arylsulphenyl, thio, alkylthio, alkenylthio, alkynylthio, arylthio, aralkylthio, carbocyclylthio, heterocyclylthio, heteroarylthio, acylthio, sulfoxide, sulfonyl, sulfonamide, aminoalkyl, aminoalkenyl, aminoalkynyl, aminocarbocyclyl, aminoaryl, aminoheterocyclyl, aminoheteroaryl, aminoacyl, aminoaralkyl, thioalkyl, thioalkenyl, thioalkynyl, thiocarbocyclyl, thioaryl, thioheterocyclyl, thioheteroaryl, thioacyl, thioaralkyl, carboxyalkyl, carboxyalkenyl, carboxyalkynyl, carboxycarbocyclyl, carboxyaryl, carboxyheterocyclyl, carboxyheteroaryl, carboxyacyl, carboxyaralkyl, carboxyesteralkyl, carboxyesteralkenyl, carboxyesteralkynyl, carboxyestercarbocyclyl, carboxyesteraryl, carboxyesterheterocyclyl , carboxyesterheteroaryl , carboxyesteracyl , carboxyesteraralkyl, amidoalkyl, amidoalkenyl, amidoalkynyl, amidocarbocyclyl, amidoaryl, amidoheterocyclyl, amidoheteroaryl, amidoacyl, amidoaralkyl, formylalkyl, formylalkenyl, formylalkynyl, formylcarbocyclyl, formylaryl, formylheterocyclyl, formyl heteroaryl, formylacyl, formylaralkyl, acylalkyl, acylalkenyl, acylalkynyl, acylcarbocyclyl, acylaryl, acylheterocyclyl, acylheteroaryl, acylacyl, acylaralkyl, sulfoxidealkyl, sulfoxidealkenyl, sulfoxidealkynyl, sulfoxidecarbocyclyl, sulfoxidearyl, sulfoxideheterocyclyl, sulfoxideheteroaryl, sulfoxideacyl, sulfoxidearalkyl, sulfonylalkyl, sulfonylalkenyl, sulfonylalkynyl, sulfonylcarbocyclyl, sulfonylaryl, sulfonylheterocyclyl, sulfonylheteroaryl, sulfonylacyl, sulfonylaralkyi, sulfonamidoalkyi, sulfonamidoalkenyl, sulfonamidoalkynyl, sulfonamidocarbocyclyl, sulfonamidoaryl, sulfonamidoheterocyclyl, sulfonamidoheteroaryl, sulfonamidoacyl, sulfonamidoaralkyl, nitroalkyl, nitroalkenyl, nitroalkynyl, nitrocarbocyclyl, nitroaryl, nitroheterocyclyl, nitroheteroaryl, nitroacyl, nitroaralkyl, cyano, sulfate and phosphate groups.

[00011 ] The optional substituents present on

to R₈ of the donor component may be independently selected from amino, alkylamino, thio, alkylthio, halo, alkylhalo and alkoxy;

[00012] One or more of the substituents R₃, R₄, R₇ and R₈ may be hydrogen. The substituents Ri , R₂, R5 and R₆ may be independently selected from optionally substituted alkyl where the number of carbons in the chain is greater than 3, or greater than 4, or greater than 5, or greater than 6. R₂ and R₆ may be n-hexyl. R and R₅ may be dimethyloctyl. Ri and R₅ may be 2-ethylhexyl.

[00013] The acceptor units may be selected from one or more of structures 3, 4 or 5. The acceptor units may be structure 3. The acceptor units may be structure 3 and one or more of the substituents R₃, R₄, R₇ and R₈ of the donor component may be hydrogen and the substituents Ri , R₂, R5 and R₆ of the donor component may be independently selected from optionally substituted alkyl where the number of carbons in the chain is greater than 3, or greater than 4, or greater than 5, or greater than 6. The acceptor units may be structure 3 and R₂ and R₆ may be n-hexyl and Ri and R₅ may be dimethyloctyl or R and R₅ may be 2-ethylhexyl.

[00014] The nature of the benzodithiophene substituents Ri to R₈ may be varied to improve solution processibility, that is, increase solubility, while the acceptor group component may be modified to alter the HOMO-LUMO energy gap, solution processibility, for example to increase solubility, and to improve device efficiencies in bulk heterojunction solar cell efficiencies in blends formed with fullerenes and other acceptor molecules.

[00015] The polymers may have number average molar mass or number average molecular weight in the range of 1 0,000<Mn<200,000 Daltons, or in the range 20,000<Mn<175,000 Daltons, or in the range 30, 000<Mn<150,000 Daltons. The molar mass may be in the range 40, 000<Mn<1 00,000 Daltons. The molar mass may be greater than 1 0,000 Daltons, or greater than 20,000 Daltons, or greater than 30,000 Daltons, or greater than 40,000 Daltons, or greater than 50,000 Daltons, or greater than 60,000 Daltons, or greater than 70,000 Daltons, or greater than 80,000 Daltons, or greater than 90,000 Daltons, or greater than 100,000 Daltons, or greater than 1 10,000 Daltons.

[00016] The polymers may be prepared by a continuous synthesis process. The synthesis procedures may be amenable to scale up using continuous processes as disclosed in International Patent Application No. PCT/AU2012/000837.

[00017] The polymers may be synthesised by a transition metal catalysed cross coupling reaction.

[00018] The polymers may be synthesised by Stille cross coupling.

[00019] The polymer may be synthesised by Suzuki polycondensation.

[00020] The polymers may contain endcapping groups such as phenyl endcapping groups.

[00021 ] The polymer may contain donor component 2, acceptor component 3, 4 or 5 and one or more of the substituents R₃, R₄, R₇ and R₈ may be hydrogen. The substituents R_{1 5} R₂, R5 and R₆ may be independently selected from optionally substituted alkyl where the number of carbons in the chain is greater than 3, or greater than 4, or greater than 5, or greater than 6, and the polymer may have a number average molar mass greater than 10,000 Daltons, or greater than 20,000 Daltons, or greater than 30,000 Daltons, or greater than 40,000 Daltons, or greater than 50,000 Daltons, or greater than 60,000 Daltons, or greater than 70,000 Daltons, or greater than 80,000 Daltons, or greater than 90,000 Daltons, or greater than 100,000 Daltons, or greater than 1 10,000 Daltons. The polymer may contain endcapping groups such as phenyl endcapping groups.

[00022] The polymer may contain donor component 2, acceptor component 3 and one or more of the substituents R₃, R₄, R₇ and R₈ may be hydrogen. The substituents Ri , R₂, R5 and R₆ may be independently selected from optionally substituted alkyl where the number of carbons in the chain is greater than 3, or greater than 4, or greater than 5, or greater than 6, and the polymer may have a number average molar mass greater than 10,000 Daltons, or greater than 20,000 Daltons, or greater than 30,000 Daltons, or greater than 40,000 Daltons, or greater than 50,000 Daltons, or greater than 60,000 Daltons, or greater than 70,000 Daltons, or greater than 80,000 Daltons, or greater than 90,000 Daltons, or greater than 100,000 Daltons, or greater than 1 10,000 Daltons. The polymer may contain endcapping groups such as phenyl endcapping groups. [00023] The polymer may contain donor component 2, acceptor component 3 wherein the substituents R₃, R₄, R₇ and R₈ are hydrogen. The substituents Ri , R₂, R5 and R₆ may be independently selected from optionally substituted alkyl where the number of carbons in the chain is greater than 3, or greater than 4, or greater than 5, or greater than 6, and the polymer has a number average molar mass greater than 80,000 Daltons, or greater than 90,000 Daltons, or greater than 100,000 Daltons, or greater than 1 10,000 Daltons. The polymer may contain endcapping groups such as phenyl endcapping groups.

[00024] The polymer may contain donor component 2, acceptor component 3 wherein the substituents R₃, R₄, R₇ and R₈ are hydrogen. The substituents Ri , R₂, R5 and R₆ may be independently selected from optionally substituted alkyl where the number of carbons in the chain is greater than 6, and the polymer has a number average molar mass greater than 80,000 Daltons, or greater than 90,000 Daltons, or greater than 100,000 Daltons, or greater than 1 10,000 Daltons. The polymer may contain endcapping groups such as phenyl endcapping groups.

[00025] In a second aspect there is provided a method of preparing a polymer of formula (1 ) as hereinbefore disclosed comprising a step of transition metal catalysed cross coupling such as Stille crosscoupling or Suzuki polycondensation.

[00026] The method may provide polymers having a number average molar mass in the range of 10,000<Mn<200,000 Daltons, or in the range 20, 000<Mn<175,000 Daltons, or in the range 30,000<Mn<150,000 Daltons. The molar mass may be in the range 40,000<Mn<100,000 Daltons. The molar mass may be greater than 10,000 Daltons, or greater than 20,000 Daltons, or greater than 30,000 Daltons, or greater than 40,000 Daltons, or greater than 50,000 Daltons, or greater than 60,000 Daltons, or greater than 70,000 Daltons, or greater than 80,000 Daltons, or greater than 90,000 Daltons, or greater than 100,000 Daltons, or greater than 1 10,000 Daltons.

[00027] In a third aspect there is provided a heterojunction device comprising one or more polymers as hereinbefore disclosed. The device may be a solar cell.

[00028] In a fourth aspect there is provided the use of one or more polymers as hereinbefore disclosed in the fabrication of a photovoltaic device. The device may be a solar cell.

[00029] The heterojunction devices may be fabricated with one or more fullerenes. The fullerenes may be ΡΟβιΒΜ, PC₇₁ BM or mixtures thereof. [00030] The devices may display a high open circuit voltage V_oc in the range 0.8 - 1 .1 V

[00031 ] Surprisingly high energy conversion efficiencies may be observed for devices containing polymers having number average molar mass (high temperature GPC-determined number average molar mass against polystyrene standards) in the range 40, 000<Mn<100,000 Daltons. These are significantly higher than the preferred number average molar masses previously reported. [G. Dennler, M. C. Scharber and C. J. Brabec, Adv. Mater. 2009, 21 , 1323]

[00032] Devices containing fullerene derivatives blended with polymers as hereinbefore disclosed may show good device stability when thermally treated at up to 80 °C. This is particularly advantageous for device fabrication in, for example, roll- to-roll printing where thermal treatment is often required for efficient layer by layer deposition of materials.

[00033] Without wishing to be bound by theory, the surprising combination of specific polymer structure with the mode of synthesis, either by batch or preferably under continuous flow processes leads to photovoltaic devices with high efficiencies. Selection of material with number average molar mass in the range 40,000-100,000 Daltons affords surprisingly high solar cell device efficiencies.

[00034] Without wishing to be bound by theory, there appears to be a correlation between improved device performance and use of polymers with M_n in the range 40,000 - 100,000 Daltons. It is expected that higher molecular weight polymer materials provide more desirable bulk heterojunction morphology when blended with fullerene derivatives and nanoscale domains with higher crystallinity are present for improved charge transport. In addition, the higher molecular weight material endcapped with phenyl units may give stable devices after thermal treatment. This makes the material particularly suited for roll-to-roll fabrication of large area solar cell devices.

[00035] Throughout this specification, use of the terms "comprises" or "comprising" or grammatical variations thereon shall be taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof not specifically mentioned. BRIEF DESCRIPTION OF THE DRAWINGS

[00036] FIGURE 1 presents current density vs. voltage curves of soiar cell devices (inverted device geometry) containing polymer 30 (Suzuki) blended with

[00037] FIGURE 2 presents a tapping mode atomic force microscopy (AFM) image of blend film of polymer 30 (prepared by Suzuki polycondensation) and PC71BM 1 :2 w/w, showing nanoscale phase separation of the domains.

[00038] FIGURE 3 presents current density vs. voltage curves of sofar cell devices (inverted device geometry) containing polymer 30 (Suzuki) blended with PC71BM showing thermal stability when the devices were heated up to 120 "C (3 min).

DETAILED DESCRIPTION

[00039] It will now be convenient to describe the invention with reference to particular embodiments and examples. These embodiments and examples are illustrative only and should not be construed as limiting upon the scope of the invention. It will be understood that variations upon the described invention as would be apparent to the skilled artisan are within the scope of the invention. Similarly, the present invention is capable of finding application in areas that are not explicitly recited In this document and the fact that some applications are not specifically described should not be considered as a limitation on the overall applicability of the invention.

[00040] In this specification "optionally substituted" is taken to mean that a group may or may not be substituted or fused (so as to form a condensed polycyclic group) with one, two, three or more of organic and inorganic groups (i.e. the optional substituent) including those selected from: alkyl, alkenyl, a!kynyl, carbocyc!yl, aryi, heterocyclyl, heteroaryl, acyi, aralkyl, alkaryl, alkheterocydyl, alkheteroaryi, aikcarbocyclyl, halo, haioalkyl, haloalkenyl, haloalkynyi, haloaryi, ha!ocarbocyclyi, haloheterocyclyl, haloheteroaryl, haloacyl, haloaryalkyl, hydroxy, hydroxya!kyl, hydroxyalkenyl, hydroxyaikynyl, hydroxycarbocyclyl, hydroxyaryl, hydroxyheterocyclyl, hydroxyheteroaryl, hydroxyacyl, hydroxyaralkyl, alkoxyalkyl, alkoxyalkenyl, aikoxyalkynyl, alkoxycarbocyc!yl, alkoxyaryl, alkoxyheterocyclyi, alkoxyheteroaryf, alkoxyacyl, alkoxyaralkyl, alkoxy, alkenyloxy, alkynyloxy, aryloxy, carbocyclyloxy,

RECTIFIED SHEET aralkyloxy, heteroaryloxy, heterocyclyloxy, acyloxy, haloalkoxy, haloalkenyloxy, haloalkynyloxy, haloaryloxy, halocarbocyclyloxy, haloaralkyloxy, haloheteroaryloxy, haloheterocyclyloxy, haloacyloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, nitroheteroayl, nitrocarbocyclyl, nitroacyl, nitroaralkyl, amino (NH2), alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, aralkylamino, diaralkylamino, acylamino, diacylamino, heterocyclamino, heteroarylamino, carboxy, carboxyester, amido, alkylsulphonyloxy, arylsulphenyloxy, alkylsulphenyl, arylsulphenyl, thio, alkylthio, alkenylthio, alkynylthio, arylthio, aralkylthio, carbocyclylthio, heterocyclylthio, heteroarylthio, acylthio, sulfoxide, sulfonyl, sulfonamide, aminoalkyl, aminoalkenyl, aminoalkynyl, aminocarbocyclyl, aminoaryl, aminoheterocyclyl, aminoheteroaryl, aminoacyl, aminoaralkyl, thioalkyl, thioalkenyl, thioalkynyl, thiocarbocyclyl, thioaryl, thioheterocyclyl, thioheteroaryl, thioacyl, thioaralkyl, carboxyalkyl, carboxyalkenyl, carboxyalkynyl, carboxycarbocyclyl, carboxyaryl, carboxyheterocyclyl, carboxyheteroaryl, carboxyacyl, carboxyaralkyl, carboxyesteralkyl, carboxyesteralkenyl, carboxyesteralkynyl, carboxyestercarbocyclyl, carboxyesteraryl, carboxyesterheterocyclyl , carboxyesterheteroaryl , carboxyesteracyl , carboxyesteraralkyl, amidoalkyl, amidoalkenyl, amidoalkynyl, amidocarbocyclyl, amidoaryl, amidoheterocyclyl, amidoheteroaryl, amidoacyl, amidoaralkyl, formylalkyl, formylalkenyl, formylalkynyl, formylcarbocyclyl, formylaryl, formylheterocyclyl, formylheteroaryl, formylacyl, formylaralkyl, acylalkyl, acylalkenyl, acylalkynyl, acylcarbocyclyl, acylaryl, acylheterocyclyl, acylheteroaryl, acylacyl, acylaralkyl, sulfoxidealkyl, sulfoxidealkenyl, sulfoxidealkynyl, sulfoxidecarbocyclyl, sulfoxidearyl, sulfoxideheterocyclyl, sulfoxideheteroaryl, sulfoxideacyl, sulfoxidearalkyl, sulfonylalkyl, sulfonylalkenyl, sulfonylalkynyl, sulfonylcarbocyclyl, sulfonylaryl, sulfonylheterocyclyl, sulfonylheteroaryl, sulfonylacyl, sulfonylaralkyi, sulfonamidoalkyi, sulfonamidoalkenyl, sulfonamidoalkynyl, sulfonamidocarbocyclyl, sulfonamidoaryl, sulfonamidoheterocyclyl, sulfonamidoheteroaryl, sulfonamidoacyl, sulfonamidoaralkyi, nitroalkyl, nitroalkenyl, nitroalkynyl, nitrocarbocyclyl, nitroaryl, nitroheterocyclyl, nitroheteroaryl, nitroacyl, nitroaralkyl, cyano, sulfate and phosphate groups.

[00041 ] Preferred optional substituents include alkyl, (e.g. Ci-6 alkyl such as methyl, ethyl, propyl, butyl, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl), hydroxyalkyl (e.g. hydroxymethyl, hydroxyethyl, hydroxypropyl), alkoxyalkyl (e.g. methoxymethyl, methoxyethyl, methoxypropyl, ethoxymethyl, ethoxyethyl, ethoxypropyl etc) alkoxy (e.g. Ci_-6alkoxy such as methoxy, ethoxy, propoxy, butoxy, cyclopropoxy, cyclobutoxy), halo, trifluoromethyl, trichloromethyl, tribromomethyl, hydroxy, phenyl (which itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy, hydroxyC1-6alkyl, C1-6alkoxy, haloC1-6alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), benzyl (wherein benzyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy, hydroxyC1-6alkyl, C1-6 alkoxy, haloC1-6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), phenoxy (wherein phenyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy, hydroxyC1-6 alkyl, C1-6 alkoxy, haloC1-6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), benzyloxy (wherein benzyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy, hydroxyC1-6 alkyl, C1-6 alkoxy, haloC1-6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), amino, alkylamino (e.g. C1-6 alkyl, such as methylamino, ethylamino, propylamino etc), dialkylamino (e.g. C1-6 alkyl, such as dimethylamino, diethylamino, dipropylamino), acylamino (e.g. NHC(0)CH3), phenylamino (wherein phenyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy hydroxyC1-6 alkyl, C1-6 alkoxy, haloCI- 6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), nitro, formyl, -C(0)-alkyl (e.g. C1- 6 alkyl, such as acetyl), 0-C(0)-alkyl (e.g. C1-6alkyl, such as acetyloxy), benzoyl (wherein the phenyl group itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy hydroxyC1-6 alkyl, C1-6 alkoxy, haloC1-6 alkyl, cyano, nitro OC(0)C1-6alkyl, and amino), replacement of CH2 with C=0, C02H, C02alkyl (e.g. C1-6 alkyl such as methyl ester, ethyl ester, propyl ester, butyl ester), C02-phenyl (wherein phenyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy, hydroxyl C1-6 alkyl, C1- 6 alkoxy, halo C1-6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), CONH2, CONHphenyl (wherein phenyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy, hydroxyl C1-6 alkyl, C1-6 alkoxy, halo C1-6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), CONHbenzyl (wherein benzyl itself may be further substituted e.g., by C1-6 alkyl, halo, hydroxy hydroxyl C1-6 alkyl, C1-6 alkoxy, halo C1-6 alkyl, cyano, nitro OC(0)C1-6 alkyl, and amino), CONHalkyl (e.g. C1-6 alkyl such as methyl ester, ethyl ester, propyl ester, butyl amide) CONHdialkyl (e.g. C1-6 alkyl)aminoalkyl (e.g., HN C1-6 alkyl-, C1-6alkylHN-C1-6 alkyl- and (C1-6 alkyl)2N- C1-6 alkyl-), thioalkyl (e.g., HS C1-6 alkyl-), carboxyalkyl (e.g., H02CC1-6 alkyl-), carboxyesteralkyl (e.g., C1-6 alkyl02CC1-6 alkyl-), amidoalkyl (e.g., H2N(0)CC1-6 alkyl-, H(C1-6 alkyON(0)CC1-6 alkyl-), formylalkyl (e.g., OHCC1-6alkyl-), acylalkyl (e.g., C1 -6 alkyl(0)CC1 -6 alkyl-), nitroalkyl (e.g., 02NC1 -6 alkyl-), sulfoxidealkyl (e.g., R3(0)SC1 -6 alkyl, such as C1 -6 alkyl(0)SC1 -6 alkyl-), sulfonylalkyl (e.g., R3(0)2SC1 -6 alkyl- such as C1 -6 alkyl(0)2SC1 -6 alkyl-), sulfonamidoalkyl (e.g., 2HRN(0)SC1 -6 alkyl, H(C1 -6 alkyl)N(0)SC1 -6alkyl-).

[00042] As used herein, the term "alkyl", used either alone or in compound words denotes straight chain, branched or cyclic alkyl, for example Ci_-40 alkyl, or C1 - 20 or C1 -10. Examples of straight chain and branched alkyl include methyl, ethyl, n- propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, n-hexyl, 1 ,2-dimethylpropyl, 1 ,1 - dimethyl-propyl, hexyl, 4-methylpentyl, 1 -methylpentyl, 2-methylpentyl, 3- methylpentyl, 1 ,1 -dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1 ,2- dimethylbutyl, 1 ,3-dimethylbutyl, 1 ,2,2-trimethylpropyl, 1 ,1 ,2-trimethylpropyl, heptyl, 5-methylhexyl, 1 -methylhexyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 4,4- dimethylpentyl, 1 ,2-dimethylpentyl, 1 ,3-dimethylpentyl, 1 ,4-dimethyl-pentyl, 1 ,2,3- trimethylbutyl, 1 , 1 ,2-trimethylbutyl, 1 ,1 ,3-trimethylbutyl, octyl, 6-methylheptyl, 1 - methylheptyl, 1 ,1 ,3,3-tetramethylbutyl, nonyl, 1 -, 2-, 3-, 4-, 5-, 6- or 7-methyloctyl, 1 -, 2-, 3-, 4- or 5-ethylheptyl, 1 -, 2- or 3-propylhexyl, decyl, 1 -, 2-, 3-, 4-, 5-, 6-, 7- and 8- methylnonyl, 1 -, 2-, 3-, 4-, 5- or 6-ethyloctyl, 1 -, 2-, 3- or 4-propylheptyl, dimethyloctyl, undecyl, 1 -, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-methyldecyl, 1 -, 2-, 3-, 4-, 5-, 6- or 7- ethylnonyl, 1 -, 2-, 3-, 4- or 5-propyloctyl, 1 -, 2- or 3-butylheptyl, 1 -pentylhexyl, dodecyl, 1 -, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-methylundecyl, 1 -, 2-, 3-, 4-, 5-, 6-, 7- or 8-ethyldecyl, 1 -, 2-, 3-, 4-, 5- or 6-propylnonyl, 1 -, 2-, 3- or 4-butyloctyl, 1 -2- pentylheptyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonoadecyl, eicosyl and the like. Examples of cyclic alkyl include mono- or polycyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl and the like. Where an alkyl group is referred to generally as "propyl", butyl" etc, it will be understood that this can refer to any of straight, branched and cyclic isomers where appropriate. An alkyl group may be optionally substituted by one or more optional substituents as herein defined.

[00043] As used herein, term "alkenyl" denotes groups formed from straight chain, branched or cyclic hydrocarbon residues containing at least one carbon to carbon double bond including ethylenically mono-, di- or polyunsaturated alkyl or cycloalkyl groups as previously defined, for example C2-40 alkenyl, or C2-20 or C2- 10. Thus, alkenyl is intended to include propenyl, butylenyl, pentenyl, hexaenyl, heptaenyl, octaenyl, nonaenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nondecenyl, eicosenyl hydrocarbon groups with one or more carbon to carbon double bonds. Examples of alkenyl include vinyl, allyl, 1 -methylvinyl, butenyl, iso-butenyl, 3-methyl-

2- butenyl, 1 -pentenyl, cyclopentenyl, 1 -methyl-cyclopentenyl, 1 -hexenyl, 3-hexenyl, cyclohexenyl, 1 -heptenyl, 3-heptenyl, 1 -octenyl, cyclooctenyl, 1 -nonenyl, 2-nonenyl,

3- nonenyl, 1 -decenyl, 3-decenyl, 1 ,3-butadienyl, 1 ,4-pentadienyl, 1 ,3- cyclopentadienyl, 1 ,3-hexadienyl, 1 ,4-hexadienyl, 1 ,3-cyclohexadienyl, 1 ,4- cyclohexadienyl, 1 ,3-cycloheptadienyl, 1 ,3,5-cycloheptatrienyl and 1 ,3,5,7- cyclooctatetraenyl. An alkenyl group may be optionally substituted by one or more optional substituents as herein defined.

[00044] As used herein the term "alkynyl" denotes groups formed from straight chain, branched or cyclic hydrocarbon residues containing at least one carbon- carbon triple bond including ethylenically mono-, di- or polyunsaturated alkyl or cycloalkyl groups as previously defined, for example, C2-40 alkenyl, or C2-20 or C2- 10. Thus, alkynyl is intended to include propynyl, butylynyl, pentynyl, hexaynyl, heptaynyl, octaynyl, nonaynyl, decynyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, pentadecynyl, hexadecynyl, heptadecynyl, octadecynyl, nondecynyl, eicosynyl hydrocarbon groups with one or more carbon to carbon triple bonds. Examples of alkynyl include ethynyl, 1 -propynyl, 2-propynyl, and butynyl isomers, and pentynyl isomers. An alkynyl group may be optionally substituted by one or more optional substituents as herein defined.

[00045] An alkenyl group may comprise a carbon to carbon triple bond and an alkynyl group may comprise a carbon to carbon double bond (i.e. so called ene-yne or yne-ene groups).

[00046] As used herein, the term "aryl" (or "carboaryl)" denotes any of single, polynuclear, conjugated and fused residues of aromatic hydrocarbon ring systems. Examples of aryl include phenyl, biphenyl, terphenyl, quaterphenyl, naphthyl, tetrahydronaphthyl, anthracenyl, dihydroanthracenyl, benzanthracenyl, dibenzanthracenyl, phenanthrenyl, fluorenyl, pyrenyl, idenyl, azulenyl, chrysenyl. Preferred aryl include phenyl and naphthyl. An aryl group may be optionally substituted by one or more optional substituents as herein defined. [00047] As used herein, the terms "alkylene", "alkenylene", and "arylene" are intended to denote the divalent forms of "alkyl", "alkenyl", and "aryl", respectively, as herein defined.

[00048] The term "halogen" ("halo") denotes fluorine, chlorine, bromine or iodine (fluoro, chloro, bromo or iodo).

[00049] The term "carbocyclyl" includes any of non-aromatic monocyclic, polycyclic, fused or conjugated hydrocarbon residues, preferably C3-20 (e.g. C3-10 or C3-8). The rings may be saturated, e.g. cycloalkyl, or may possess one or more double bonds (cycloalkenyl) and/or one or more triple bonds (cycloalkynyl). Particularly preferred carbocyclyl moieties are 5-6-membered or 9-10 membered ring systems. Suitable examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cyclopentenyl, cyclohexenyl, cyclooctenyl, cyclopentadienyl, cyclohexadienyl, cyclooctatetraenyl, indanyl, decalinyl and indenyl.

[00050] The term "heterocyclyl" when used alone or in compound words includes any of monocyclic, polycyclic, fused or conjugated hydrocarbon residues, preferably C3-20 (e.g. C₃-i₀ or C₃-₈) wherein one or more carbon atoms are replaced by a heteroatom so as to provide a non-aromatic residue. Suitable heteroatoms include O, N, S, P and Se, particularly O, N and S. Where two or more carbon atoms are replaced, this may be by two or more of the same heteroatom or by different heteroatoms. The heterocyclyl group may be saturated or partially unsaturated, i.e. possess one or more double bonds. Particularly preferred heterocyclyl are 5-6 and 9- 10 membered heterocyclyl. Suitable examples of heterocyclyl groups may include azridinyl, oxiranyl, thiiranyl, azetidinyl, oxetanyl, thietanyl, 2H-pyrrolyl, pyrrolidinyl, pyrrolinyl, piperidyl, piperazinyl, morpholinyl, indolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, thiomorpholinyl, dioxanyl, tetrahydrofuranyl, tetrahydropyranyl, tetrahydropyrrolyl, tetrahydrothiophenyl, pyrazolinyl, dioxalanyl, thiazolidinyl, isoxazolidinyl, dihydropyranyl, oxazinyl, thiazinyl, thiomorpholinyl, oxathianyl, dithianyl, trioxanyl, thiadiazinyl, dithiazinyl, trithianyl, azepinyl, oxepinyl, thiepinyl, indenyl, indanyl, 3H-indolyl, isoindolinyl, 4H-quinolazinyl, chromenyl, chromanyl, isochromanyl, pyranyl and dihydropyranyl.

[00051 ] The term "heteroaryl" includes any of monocyclic, polycyclic, fused or conjugated hydrocarbon residues, wherein one or more carbon atoms are replaced by a heteroatom so as to provide an aromatic residue. Preferred heteroaryl have 3- 20 ring atoms, e.g. 3-10. Particularly preferred heteroaryl are 5-6 and 9-10 membered bicyclic ring systems. Suitable heteroatoms include, O, N, S, P and Se, particularly O, N and S. Where two or more carbon atoms are replaced, this may be by two or more of the same heteroatom or by different heteroatoms. Suitable examples of heteroaryl groups may include pyridyl, pyrrolyl, thienyl, imidazolyl, furanyl, benzothienyl, isobenzothienyl, benzofuranyl, isobenzofuranyl, indolyl, isoindolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, quinolyl, isoquinolyl, phthalazinyl, 1 ,5-naphthyridinyl, quinozalinyl, quinazolinyl, quinolinyl, oxazolyl, thiazolyl, isothiazolyl, isoxazolyl, triazolyl, oxadialzolyl, oxatriazolyl, triazinyl, and furazanyl.

[00052] The term "acyl" either alone or in compound words denotes a group containing the agent C=0 (and not being a carboxylic acid, ester or amide). Preferred acyl includes C(0)-Rx, wherein Rx is hydrogen or an alkyl, alkenyl, alkynyl, aryl, heteroaryl, carbocyclyl, or heterocyclyl residue. Examples of acyl include formyl, straight chain or branched alkanoyl (e.g. C1-20) such as, acetyl, propanoyl, butanoyl, 2-methylpropanoyl, pentanoyl, 2,2-dimethylpropanoyl, hexanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl, undecanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, pentadecanoyl, hexadecanoyl, heptadecanoyl, octadecanoyl, nonadecanoyl and icosanoyl; cycloalkylcarbonyl such as cyclopropylcarbonyl cyclobutylcarbonyl, cyclopentylcarbonyl and cyclohexylcarbonyl; aroyl such as benzoyl, toluoyl and naphthoyl; aralkanoyl such as phenylalkanoyl (e.g. phenylacetyl, phenylpropanoyl, phenylbutanoyl, phenylisobutylyl, phenylpentanoyl and phenylhexanoyl) and naphthylalkanoyl (e.g. naphthylacetyl, naphthylpropanoyl and naphthylbutanoyl]; aralkenoyl such as phenylalkenoyl (e.g. phenylpropenoyl, phenylbutenoyl, phenylmethacryloyl, phenylpentenoyl and phenylhexenoyl and naphthylalkenoyl (e.g. naphthylpropenoyl, naphthylbutenoyl and naphthylpentenoyl); aryloxyalkanoyl such as phenoxyacetyl and phenoxypropionyl; arylthiocarbamoyl such as phenylthiocarbamoyl; arylglyoxyloyl such as phenylglyoxyloyl and naphthylglyoxyloyl; arylsulfonyl such as phenylsulfonyl and napthylsulfonyl; heterocycliccarbonyl; heterocyclicalkanoyl such as thienylacetyl, thienylpropanoyl, thienylbutanoyl, thienylpentanoyl, thienylhexanoyl, thiazolylacetyl, thiadiazolylacetyl and tetrazolylacetyl; heterocyclicalkenoyl such as heterocyclicpropenoyl, heterocyclicbutenoyl, heterocyclicpentenoyl and heterocyclichexenoyl; and heterocyclicglyoxyloyl such as th iazolyg lyoxy loyl and thienylglyoxyloyl. The Rx residue may be optionally substituted as described herein.

[00053] The term "sulfoxide", either alone or in a compound word, refers to a group -S(0)Ry wherein Ry is selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, carbocyclyl, and aralkyl. Examples of preferred Ry include C1 -20alkyl, phenyl and benzyl.

[00054] The term "sulfonyl", either alone or in a compound word, refers to a group S(0)₂-Ry, wherein Ry is selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, carbocyclyl and aralkyl. Examples of preferred Ry include C1 -20alkyl, phenyl and benzyl.

[00055] The term "sulfonamide", either alone or in a compound word, refers to a group S(0)NRyRy wherein each Ry is independently selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, carbocyclyl, and aralkyl. Examples of preferred Ry include C1 -20alkyl, phenyl and benzyl. In a preferred embodiment at least one R_Y is hydrogen. In another form, both Ry are hydrogen.

[00056] The term, "amino" is used herein its broadest sense as understood in the art and includes groups of the formula NR^AR^B wherein R^A and R^B may be any independently selected from hydrogen, alkyl, alkenyl, alkynyl, aryl, carbocyclyl, heteroaryl, heterocyclyl, aralkyl, and acyl. R^A and R^B, together with the nitrogen to which they are attached, may also form a monocyclic, or polycyclic ring system e.g. a 3-10 membered ring, particularly, 5-6 and 9-10 membered systems. Examples of "amino" include NH2, NHalkyl (e.g. C1 -20alkyl), NHaryl (e.g. NHphenyl), NHaralkyl (e.g. NHbenzyl), NHacyl (e.g. NHC(O)C1 -20alkyl, NHC(O)phenyl), Nalkylalkyl (wherein each alkyl, for example C1 -20, may be the same or different) and 5 or 6 membered rings, optionally containing one or more same or different heteroatoms (e.g. O, N and S).

[00057] The term "amido" is used here in its broadest sense as understood in the art and includes groups having the formula C(0)NR^AR^B, wherein R^A and R^B are as defined as above. Examples of amido include C(0)NH2, C(0)NHalkyl (e.g. C1 - 20alkyl), C(0)NHaryl (e.g. C(O)NHphenyl), C(0)NHaralkyl (e.g. C(O)NHbenzyl), C(0)NHacyl (e.g. C(O)NHC(O)C1 -20alkyl, C(0)NHC(0)phenyl), C(0)Nalkylalkyl (wherein each alkyl, for example C1 -20, may be the same or different) and 5 or 6 membered rings, optionally containing one or more same or different heteroatoms (e.g. O, N and S).

[00058] The term "carboxy ester" is used here in its broadest sense as understood in the art and includes groups having the formula C02R^Z, wherein R^z may be selected from groups including alkyl, alkenyl, alkynyl, aryl, carbocyclyl, heteroaryl, heterocyclyl, aralkyl, and acyl. Examples of carboxy ester include C02C1 - 20alkyl, C02aryl (e.g. C02phenyl), C02aralkyl (e.g. C02 benzyl).

[00059] The term "heteroatom" or "hetero" as used herein in its broadest sense refers to any atom other than a carbon atom which may be a member of a cyclic organic group. Particular examples of heteroatoms include nitrogen, oxygen, sulfur, phosphorous, boron, silicon, selenium and tellurium, more particularly nitrogen, oxygen and sulfur.

[00060] Polymer 30 was prepared by both Stille cross coupling and Suzuki polycondensation procedures (SCHEME 2). The synthesis procedures are described in the worked examples.

SCHEME 2: a) Synthesis of benzodithiophene monomer building blocks; b) synthesis of polymer 30 via Stille cross coupling and c) synthesis of polymer 30 via Suzuki polycondensation.

[00061] Devices were fabricated with polymer 30 blended with ΡΟβιΒΜ or PC71 BM. Details on device fabrication and characterisation can be found in the worked examples.

[00062] Devices fabricated from polymer 30 show the following features:

(a) A high open circuit voltage V_oc in the range 0.8 - 1 .1 V

(b) Surprisingly high energy conversion efficiencies for polymers having number average molar mass (high temperature GPC-determined number average molar mass against polystyrene standards) in the range 40, 000<Mn<100,000 Daltons. These are significantly higher than the preferred number average molar masses disclosed in the prior art.[G. Dennler, M. C. Scharber and C. J. Brabec, Adv. Mater. 2009, 21 , 1323]

(c) A strong dependence of number average molar mass attainable leading to solar cell device efficiencies dependent on the method of polymer synthesis. The Suzuki polycondensation method is surprisingly fast and delivers much higher molar mass material (up to Mn 175,000 Daltons) than Stille cross-coupling.

(d) Devices containing fullerene derivatives blended with polymer 30 synthesised using Suzuki polycondensation and endcapped with phenyl units show good device stability when thermally treated at up to 80 °C. This is particularly advantageous for device fabrication in roll-to-roll printing where thermal treatment is often required for efficient layer by layer deposition of materials.

[00063] It is surprising that polymer 30 when synthesised by conventional Stille cross coupling procedures exhibits number average molar mass properties (high temperature GPC-determined number average molar mass against polystyrene standards) of about 40,000 Daltons, whereas the same polymer prepared by Suzuki polycondensation routinely affords material of number average molar mass of greater than 80,000 Daltons (by high temperature GPC against polystyrene standards).

[00064] Selection of material with number average molar mass in the range 40,000-100,000 Daltons affords surprisingly high solar cell device efficiencies. For example a solar cell device fabricated with inverted geometry configuration using a 1 :2 w/w blend of polymer 30 with PC71 BM exhibits energy conversion efficiency of 5% when 30 is prepared by Stille cross-coupling compared with an efficiency of 8.5% when the polymer 30 is prepared by Suzuki polycondensation. Devices fabricated using Suzuki-synthesised polymer 30 show good thermal stability up to 80 °C. Solar cell device data is reported in the worked examples.

[00065] Without wishing to be bound by theory there appears to be a correlation between improved device performance and use of polymer 30 with M_n in the range 40,000 - 100,000 Daltons. It is expected that higher molecular weight polymer materials provide more desirable bulk heterojunction morphology when blended with fullerene derivatives and nanoscale domains with higher crystallinity are present for improved charge transport. In addition, the higher molecular weight material endcapped with phenyl units gives stable devices after thermal treatment. This makes the material particularly suited for roll-to-roll fabrication of large area solar cell devices.

EXAMPLES

Monomer synthesis

2-(2-ethylhexyl)-3-hexylthiophene (25)

[00066] To a 500 ml flask under N₂ atmosphere was added magnesium turnings (5 g, 0.205 mol), anhydrous THF (50 mL) and a small amount of iodine. A solution of 2-ethylhexylbromide 24 (35 g, 0.181 mol) in anhydrous THF (150ml_) was added slowly to this mixture using a dropping funnel at room temperature. The addition was controlled in order to maintain a constant reflux. After the addition was complete the reaction mixture was heated to reflux for 2 h and cooled back to room temperature. The resulting (2-ethylhexyl)magnesium bromide solution was added dropwise via a cannula to a 500ml two necked round bottom flask equipped with a reflux condenser containing a mixture of 2-bromo-3-hexylthiophene (30.0 g, 0.120 mole), dichloro[1 ,3-bis(diphenylphosphino)propane]nickel(ll) (165mg, 0.3 mmol) and 150 ml of anhydrous ether at 0°C. After addition is complete the mixture was warmed to room temperature and the ether started to reflux gently. The reaction mixture was stirred at room temperature overnight and heated to reflux next day for 6 hours. The mixture was cooled in an ice bath, and cautiously hydrolyzed with 2 N hydrochloric acid. The organic layer was separated and the aqueous layer extracted with two 100 ml. portions of ether. The combined organic layer and extracts were washed successively with water, aqueous saturated sodium bicarbonate, and again with water, dried over anhydrous MgS04, and filtered. After evaporation of the solvent the residue was distilled under reduced pressure to give product as a colorless liquid (29g, 85%). ¹ H NMR (400 MHz, CDCI₃) δ 7.03(d, J = 5.2Hz, 1 H), 6.81 (d, J = 5.2 Hz, 1 H), 2.65 (d, J = 7.1 Hz, 2H), 2.53 - 2.46 (m, 2H), 1 .61 - 1 .48 (m, 1 H), 1.41 - 1 .16 (m, 16H), 0.94 - 0.79 (m, 9H). ¹³C NMR (100 MHz, CDCI₃) δ 138.38, 137.71 , 128.51 , 121 .1 1 , 41 .73, 32.53, 31.98, 31 .76, 30.85, 29.27, 28.88, 28.35, 25.67, 23.05, 22.64, 14.12, 14.09, 10.87.

4,8-bis(5-(2-ethylhexyl)-4-hexylthiophen-2-yl)benzo[1 ,2-b:4,5-b']dithiophene (27)

[00067] To a oven dried 250 mL round bottom flask cooled under N₂ was added 2-(2-ethylhexyl)-3-hexylthiophene 25 (25.47 g, 90.8 mmol), 100 ml anhydrous THF and cooled to 0 °C. n-Butyllithium (88.98 mmol, 35.6 mL) was added dropwise to the solution and was heated to 50 °C for 2 hour. The reaction mixture was cooled to room temperature and benzo[1 ,2-b:4,5-b']dithiophene-4,8-dione 26 (5 g, 22.7 mmol) was added to the reaction mixture, which was then stirred for 3 h at 50 °C. After cooling the reaction mixture to room temperature, a mixture of SnCI₂-2H₂0 (15.4 g, 68.25 mmol) in 10% HCI (25 mL) was added and the mixture was stirred for additional 2 h, after which it was poured into ice water. The mixture was extracted with diethyl ether twice and the combined organic phases were washed with 10% HCI followed by water and concentrated to obtain the crude compound. Further purification was carried out by column chromatography on silica gel using petroleum spirit as the eluent to obtain pure compound as pale yellow solid (13.6 g, yield 80%). Mp 50 °C. v_max (neat solid)/cm^"1 2956, 2923, 2855, 1457, 1378, 1341 , 1205, 1093, 844, 813, 740. ¹ H NMR (400 MHz, CDCI₃) δ 7.69 (d, J = 5.6 Hz, 2H), 7.45 (d, J = 5.6 Hz, 2H), 7.22 (s, 2H), 2.75 (d, J = 7.1 Hz, 4H), 2.63 - 2.57 (m, 4H), 1 .71 - 1 .60 (m, 2H), 1 .50 - 1 .27 (m, 32H), 0.99 - 0.85 (m, 18H). ¹³C NMR (101 MHz, CDCI₃) δ 139.14, 138.82, 138.79, 137.53, 136.31 , 135.31 , 129.69, 127.26, 124.1 1 , 123.54, 41 .72, 32.67, 32.24, 31 .79, 30.82, 29.25, 28.94, 28.44, 25.92, 23.06, 22.68, 14.15, 14.12, 10.97. HRMS, ESI+: m/z 746.40647 (746.40419 calc. for C₄₆H₆₆S₄).

2,6-Bis(trimethyltin)-4,8-di(2-(2-ethylhexyl)-3-hexylthiophen-5-yl)-benzo[1 ,2- b:4.5-b ] dithiophene (28)

[00068] Compound 27 (5.0 g, 6.7 mmol) was dissolved anhydrous THF (60 mL) in a two-neck flask under the protection of argon. The solution was cooled to 0 °C, and a solution of n-BuLi (1 .6 M in hexane, 10 mL, 16 mmol) was added dropwise with stirring. After this addition, the reaction mixture was warmed to ambient temperature and stirred for 2 hours. Then the reaction mixture was cooled to 0 °C and a SnMe₃CI solution (1 M in THF, 20 ml_, 20 mmol) was added in one portion. The reaction mixture was stirred at 0 °C for 30 minutes and then warmed to room temperature for 8 hours. Subsequently, the reaction mixture was pour into petroleum ether, washed by KF saturated aqueous solution twice and water twice. Then, the organic layer was dried over MgS0₄ and concentrated to afford the yellow crude product. The crude product was further purified by recycle GPC system and finally afforded straw yellow sheet-shaped crystals (6.4 g, 89% yield).

¹H NMR (400 MHz, CDCI₃) δ 7.76 (s, 2H), 7.26 (s, 2H), 2.77 (d, J = 7.1 Hz, 4H), 1 .90 - 1 .86 (m, 4H), 1.71 - 1 .67 (m, 2H), 1 .50 - 1.35 (m, 32H), 1 .00 - 0.92 (m, 18H), 0.42 (s, 18H). ¹³C NMR (101 MHz, CDCI₃) δ 145.37, 143.08, 141 .89, 138.78, 138.64, 138.62, 137.14, 135.99, 131 .38, 129.61 , 127.51 , 125.25, 122.46, 41 .66, 32.68,

32.28, 31 .84, 30.77, 29.19, 28.95, 28.40, 25.98, 23.06, 23.02, 22.67, 14.15, 14.13, 1 1 .00, 10.95.

4,8-bis(5-(2-ethylhexyl)-4-hexylthiophen-2-yl)-2,6-diiodobenzo[1 ,2-b:4,5- b'jdithiophene (31 )

[00069] To an oven dried 250 ml flask was added compound 27 (5 g, 6.69 mmol) followed by 50 ml of THF. The reaction mixture was cooled to 0 °C and n- butyllithium (5.9 ml, 14.72 mmol) was added dropwise. The reaction mixture was then warmed to room temperature and allowed to stir for 3h. Iodine (4.25 g, 16.73 mmol) was added and the mixture was stirred for an additional 2 h at room temperature. Then the mixture was extracted into diethyl ether and the combined organic phase was washed with sodium thiosulfate followed by water, dried over anhydrous MgS0₄, and filtered. After evaporation of the solvent the crude product was purified by silica gel column chromatography using petroleum spirit to give the product as light-yellow solid (4g, yield 60%). Mp 46 °C. v_max (neat solid)/cm^"1 2955, 2923, 2854, 1508, 1457, 1378, 1347, 131 1 , 1 176, 913, 828. ¹H NMR (400 MHz, CDCI₃) δ 7.81 (s, 2H), 7.13 (s, 2H), 2.74 (dd, J = 7.1 , 2.4 Hz, 4H), 2.63 - 2.55 (m, 4H), 1 .72 - 1 .58 (m, 2H), 1 .50 - 1 .27 (m, 32H), 1 .01 - 0.88 (m, 18H). ¹³C NMR (101 MHz, CDCI₃) δ 143.15, 139.82, 139.09, 136.83, 134.31 , 133.22, 129.77, 121 .61 ,

80.29, 41 .70, 32.63, 32.25, 31 .79, 30.76, 29.23, 28.91 , 28.39, 25.93, 23.05, 22.72, 14.19, 14.16, 10.95. HRMS, ESI+: m/z 998.20125 (998.19747 calc. for C₄₆H₆₄I₂S₄). Synthesis of polymer 30 via Stille cross coupling

[00070] In a glove box, the monomer 28 (1 mmol) and 4,7-dibromo- [2,1 ,3]benzothiadiazole 29 (1 mmol) were mixed in a microwave reaction tube. After being dissolved in 5 mL of chlorobenzene, Pd(PPh₃)₄ (50 μηιοΙ) was added as the catalyst, and the tube was sealed with a Teflon® cap. The reaction mixture was heated to 100 °C for 1 minute, 135 °C for 1 minute, 170 °C for 1 hour, and 200 °C for 20 minutes using a Biotage microwave reactor. Then the achieved polymer was end- capped by reacting with 0.2 mL 2-(tributylstannyl)thiophene and 0.2 mL 2- bromothiophene at 170 °C for 20 minutes, respectively. The end-capped polymer was precipitated by addition of 50 mL methanol, filtered through a Soxhlet thimble. The precipitate was then subjected to Soxhlet extraction with acetone, ethyl acetate, n-heptane, dichloromethane and chloroform. The polymer was recovered as solid from the chloroform fraction by precipitation from methanol. The solid was dried under vacuum. HT-GPC results of the polymers are as follows: M_n 40,000, M_w 81 ,000, PDI 2.0.

¹H NMR (400 MHz, CDCI₃) δ 9.07 (br, 2H), 7.43 (br, 2H), 7.24 (br, 2H), 2.92-2.75 (br m, 8H, -CH₂-), 1 .84 (br m, -CH₂-), 1 .6-1 .4 (br m, -CH₂-), 1 .12 - 1 .01 (br m, -CH₃). Synthesis procedure for polymer 30 via Suzuki coupling

General procedure for Suzuki polymerization under batch conditions

[00071 ] Monomer 31 (99.68 mg, 0.1 mmol), Monomer 32 (38.8 mg, 0.1 mmol), tris(dibenzylideneacetone) dipalladium (8 mg, 4 mol%), tri(2-methylphenyl)phosphine (20 mg, 32 mol%) and Aliquat 336 (two drop) were added to a microwave vial, sealed and purged with N₂. Degassed toluene (2 mL) was added under N₂ to the vial followed by 2ml of 2M Na₂C0₃ solution. The reaction mixture was placed in a oil bath maintained at 90°C and stirred at this temperature for 25 min. The polymer were end capped with phenyl groups by adding 4,4,5,5-tetramethyl-2-phenyl-1 ,3,2- dioxaborolane (1 .5 eqv.) and heating for 3h followed by reacting with bromobenzene (2.5 eqv.) for 3h. The polymer was precipitated by pouring the reaction mixture into methanol. The precipitate was collected by filtration, washed with water, methanol, acetone, ethyl acetate and finally with heptane. The polymer was purified by Soxhlet extraction with ethyl acetate, heptane, dichloromethane, chloroform, xylenes, chlorobenzene and 1 ,2-dichlorobenzene sequentially. The dichloromethane, chloroform, xylenes, chlorobenzene and 1 ,2-dichlorobenzene fractions were concentrated under vacuum and precipitated in hexanes. The five fractions of precipitated polymers were filtered separately and washed with methanol and dried under high vacuum. The molecular weight distribution of the polymer fractions were determined by GPC against polystyrene standards as follows. Dichloromethane fraction: Mn 34,000, Mw 84,000, PDI 2.5

Chloroform fraction: Mn 80,000, Mw 200,000, PDI 2.5

Xylenes fraction: Mn 89,000, Mw 283,000, PDI 3.2

Chlorobenzene fraction: Mn 136,000, Mw 484,000, PDI 3.6

1 ,2-Dichlorobenzene fraction: Mn 120,000, Mw 543,000, PDI 4.5

For the chloroform fraction: ¹ H NMR (400 MHz, CDCI₃) δ 9.06 (br, 2H), 7.43 (br, 2H),

7.25 (br, 2H), 2.82-2.69 (br m, 8H, -CH₂-), 1 .84 (br m, -CH₂-), 1 .6-1 .4 (br m, -CH₂-),

1 .0 (br m, -CH₃).

General procedure for Suzuki polymerizations under flow conditions

[00072] A stock solution containing the tris(dibenzylideneacetone) dipalladium (4 mol%), tri(2-methylphenyl)phosphine (32 mol%), monomer 31 and monomer 32 (0.2 M solution in toluene, 1 ml) and the aqueous base solution (1 mL) were degassed and filtered prior injection into the sample loops. Using the PFA coil reactor units (4 x 10ml_), retention/residence time was controlled by adjusting the flow rates of degassed toluene and water. The temperature of the coil reactor was also varied for different experiments. Following the work-up described for the batch reaction, a dark blue polymer was obtained.

Bulk heterojunction device fabrication and characterisation

[00073] Polymer solar cells were processed on pre-patterned indium tin oxide (ITO) coated glass substrates with a sheet resistance of 15 Ω per square. First, a thin layer of ZnO nanopaticle (NP) was deposited on cleaned ITO substrate by spin- coating (3000 rpm) to form 30 nm of ZnO layer, followed by backing on a hot plate at 140 °C for 5 min. An active layer of the device was deposited by spin coating an orthodichlorobenzene solution (1 ml) containing 8 mg of 30 and 16 mg of PC71 BM. The thickness of the active layer was measured as 80 - 90 nm. M0O₃ (10 nm) and silver (100 nm) were thermally evaporated at ~a vacuum of 10^"7 mbar on top of active layer as a anode. The area of the devices was 0.10 mm². Film thickness was determined by Veeco Dektak 150+Surface Profiler. The current density-voltage measurements of the devices were carried out using a 1 kW Oriel solar simulator with an AM 1 .5G filter as the light source in conjunction with a Keithley 2400 source measurement unit. Solar measurements were carried out under 1000 W/m² AM 1 .5G illumination conditions. For accurate measurement, the light intensity was calibrated using a reference silicon solar cell (PV measurements Inc.) certified by the National Renewable Energy Laboratory. Device fabrication and characterizations were performed in a glove box without any encapsulation. The device geometry and current density (J) vs. voltage (V) curves are shown in FIGURE 1. Device performance parameters are summarized in TABLE 1. The surface morphology of the blend film of polymer 30 and PC71 BM (1 :2 w/w) was examined using tapping mode atomic force microscopy (FIGURE 2). Solar cell devices containing polymer 30 and PC71 BM and processed with 1 ,8-diiodooctane additive showed thermal stability when heated up to 120 °C for 3 min (FIGURE 3).

TABLE 1 Bulk heterojunction device performance parameters for devices containing polymer 30 synthesised using Suzuki polycondensation.

2

Active layer JJmA/cm ) V (V) FF (%) PCE (%

oc ^v '

30(Suzuki):PC₆₁ BM (1 :2) 11 .4 0.92 65 6.8

30(Suzuki):PC₇₁ BM (1 :2) 13.5 0.92 69 8.5

Claims

1 . A polymer of formula (1 ) comprising donor and acceptor components, wherein the donor component is represented by the formula (2)

DONOR ACCEPTOR

(1 )

wherein Ri to Rs are independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted aryl, and optionally substituted heterocyclyl; and

wherein the acceptor component is selected from one or more of the following 3 to 23;

2. A polymer according to claim 1 wherein one or more of the substituents R3, R₄, R₇ and R₈ are hydrogen.

3. A polymer according to claim 1 or claim 2 wherein the substituents Ri , R₂, R5 and R₆ are independently selected from optionally substituted alkyl wherein the number of carbons in the alkyl chain is greater than 4.

4. A polymer according to claim 1 or claim 2 wherein the substituents Ri , R2, R5 and R₆ are independently selected from optionally substituted alkyl wherein the number of carbons in the alkyl chain is greater than 5.

5. A polymer according to claim 4 wherein R₂ and R6 are n-hexyl.

6. A polymer according to claim 4 or claim 5 wherein Ri and R5 are dimethyloctyl.

7. A polymer according to claim 4 or claim 5 wherein Ri and R5 are 2-ethylhexyl.

8. A polymer according to any one of claims 1 to 7 wherein the acceptor

component is selected from one or more of structures 3, 4 or 5.

9. A polymer according to claim 8 wherein the acceptor component is structure 3.

10. A polymer according to any one of claims 1 to 9 wherein the polymer has a number average molar mass in the range of 10,000 to 200,000 Daltons.

1 1 . A polymer according to any one of claims 1 to 9 wherein the polymer has a number average molar mass greater than 70,000 Daltons.

12. A polymer according to any one of claims 1 to1 1 wherein the polymer is

synthesised by a transition metal catalysed cross coupling reaction.

13. A polymer according to any one of claims 1 to 12 wherein the polymer is

synthesised by Stille cross coupling.

14. A polymer according to any one of claims 1 to 13 wherein the polymer is

synthesised by Suzuki polycondensation.

15. A polymer according to any one of claims 1 to 14 wherein the polymer is

synthesised by a continuous process.

16. A polymer according to any one of claims 1 to 15 wherein the polymer

comprises phenyl endcaps.

17. A method of preparing a polymer according to any one of claims 1 to 16

comprising a step of transition metal catalysed cross coupling.

18. The method of claim 17 wherein the polymer has a number average molar mass of greater than 70,000 Daltons.

19. A heterojunction device comprising one or more polymers according to any one of claims 1 to 16.

20. The device according to claim 19 wherein the device is a solar cell.

21 . A solar cell fabricated using one or more polymers according to any one of claims 1 to 16 and an electron acceptor polymer or molecule.

22. A solar cell according to claim 21 wherein the electron acceptor polymer or molecule is one or more fullerene derivatives. Use of one or more polymers according to any one of claims 1 to 16 in the manufacture of a photovoltaic device.