Process of manufacturing and applications of a multi-component benzo[1,2-B:4,5-B] dithiphene-thienothiophene randomly substituted conjugated polymers for organic solar cells

Abstract

A process of polymerizing ##STR00001##
wherein the stoichiometric ratio of (f+g)(h+i) and f, g, h and i are not equal to 0. Additionally, R1, R2, R3 and R4 can be independently selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof and where the combination of R1, R2, R3 and R4 are not all identical. In addition, x and y can be different from each other and independently selected from the group consisting of: alkyl group, alkoxy group, aryl groups, ##STR00002##
where y=1-3, ##STR00003##
where y=0-12, ##STR00004##
where R5 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00005##
where R6 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00006##
where R7 and R8 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, NR.sub.9R.sub.10 where R9 and R10 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups.

Claims

1. A process comprising: polymerizing ##STR00044## wherein the stoichiometric ratio of (f+g)(h+i) and f, g, h and i are not equal to 0 wherein R1, R2, R3 and R4 are independently selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof and where the combination of R1, R2, R3 and R4 are not all identical; and X and Y are different from each other and independently selected from the group consisting of: alkyl group, alkoxy group, aryl groups, ##STR00045## where y=1-3, ##STR00046## where y=0-12, ##STR00047## where R5 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00048## where R6 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00049## where R7 and R8 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, NR.sub.9R.sub.10 where R9 and R10 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups wherein T and Z are any functional groups used in the polymerization reaction; and wherein ##STR00050## is a di-Me3Sn substituted benzo[1,2-b:4,5-b]dithiophene.

2. The process of claim 1, wherein the process produces a conjugated polymer.

3. The process of claim 1, wherein the polymerizing of f, g, h and i is regio-regular.

4. The process of claim 1, wherein the polymerizing of f, g, h and i is regio-random.

5. The process of claim 1, wherein the process produces a photovoltaic material.

6. The process of claim 5, wherein the photovoltaic devices is used as a polymer solar cell device or photodetector device.

7. The process of claim 1, wherein the process produces an active layer material for one or more electronic devices.

8. The process of claim 7, wherein the one or more electronic devices are field effect transistors, light emitting devices, and sensors, electrochromic devices and capacitors.

9. The process of claim 1, wherein the ratio of ##STR00051## in the polymer is around 25:25:25:25.

10. The process of claim 1, wherein ##STR00052## is a di-Me3Sn substituted benzo[1,2-b:4,5-b]dithiophene.

11. The process of claim 1, wherein the polymerizing reaction comprises: stille coupling, suzuki coupling, a nickel catalyzed reaction or direct arylation.

12. The process of claim 1, wherein functional group T of components f and g reacts exclusively with functional group Z of components h and i.

13. The process of claim 1, wherein T is selected from the group consisting of Me.sub.3Sn, C.sub.6H.sub.12, O.sub.2B, Br and combinations thereof.

14. A process comprising: polymerizing ##STR00053## wherein the stoichiometric ratio of (f+g)(h+i) and f, g, h and i are not equal to 0; wherein substituent T of component f and g reacts exclusively with substituents Z of components h and I; wherein R1, R2, R3and R4 are independently selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof and where the combination of R1, R2, R3 and R4 are not all identical; and x and y are different from each other and independently selected from the group consisting of: alkyl group, alkoxy group, aryl groups, ##STR00054## where y=1-3, ##STR00055## where y=0-12, ##STR00056## where R5 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00057## where R6 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00058## where R7 and R8 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, NR.sub.9R.sub.10 where R9 and R10 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups and the polymerization of f, g, h and i are selected from stille coupling, suzuki coupling, a nickel catalyzed reaction or direct arylation wherein T and Z are any functional groups used in the polymerization reaction; and wherein ##STR00059## is a di-Me3Sn substituted benzo[1,2-b:4,5-b]dithiophene.

15. A process for polymerizing ##STR00060## wherein the improvement comprises simultaneously polymerizing ##STR00061## wherein the stoichiometric ratio of (f+g)(h+i) and f, g, h and i are not equal to 0 wherein R1, R2, R3 and R4 are independently selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof and where the combination of R1, R2, R3 and R4 are not all identical; and x and y are different from each other and independently selected from the group consisting of: alkyl group, alkoxy group, aryl groups, ##STR00062## where y=1-3, ##STR00063## where y=0-12, ##STR00064## where R5 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00065## where R6 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, ##STR00066## where R7 and R8 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, NR.sub.9R.sub.10 where R9 and R10 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups wherein T and Z are any functional group used in the polymerization reaction; and wherein ##STR00067## is a di-Me3Sn substituted benzo[1,2-b:4,5-b]dithiophene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A more complete understanding of the present invention and benefits thereof may be acquired by referring to the follow description taken in conjunction with the accompanying drawings in which:

(2) The figure depicts a current-voltage diagram of a solar cell

DETAILED DESCRIPTION

(3) Turning now to the detailed description of the preferred arrangement or arrangements of the present invention, it should be understood that the inventive features and concepts may be manifested in other arrangements and that the scope of the invention is not limited to the embodiments described or illustrated. The scope of the invention is intended only to be limited by the scope of the claims that follow.

(4) Alkyl, as used herein, refers to an aliphatic hydrocarbon chains. In one embodiment the aliphatic hydrocarbon chains are of 1 to about 100 carbon atoms, preferably 1 to 30 carbon atoms, more preferably, 1 to 20 carbon atoms, and even more preferably, 1 to 10 carbon atoms and includes straight and branched chains such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, and isohexyl. In this application alkyl groups can include the possibility of substituted and unsubstituted alkyl groups.

(5) Alkoxy, as used herein, refers to the group RO where R is an alkyl group of 1 to 100 carbon atoms. In this application alkoxy groups can include the possibility of substituted and unsubstituted alkoxy groups.

(6) Aryl as used herein, refers to an optionally substituted, mono-, di-, tri-, or other multicyclic aromatic ring system having from about 5 to about 50 carbon atoms (and all combinations and subcombinations of ranges and specific numbers of carbon atoms therein), with from about 6 to about 10 carbons being preferred. Non-limiting examples include, for example, phenyl, naphthyl, anthracenyl, and phenanthrenyl. Aryl groups can be optionally substituted with one or with one or more Rx. In this application aryl groups can include the possibility of substituted aryl groups, bridged aryl groups and fused aryl groups.

(7) The present embodiment describes a process of polymerizing

(8) ##STR00026##
In this embodiment, the stoichiometric ratio of (f+g)(h+i) and f, g, h and i are not equal to 0. Additionally, in this embodiment, R1, R2, R3 and R4 can be independently selected from the group consisting of alkyl group, alkoxy group, aryl groups and combinations thereof and where the combination of R1, R2, R3 and R4 are not all identical. Additionally, in this embodiment, x and y can be different from each other and independently selected from the group consisting of: alkyl group, alkoxy group, aryl groups,

(9) ##STR00027##
where y=1-3,

(10) ##STR00028##
where y=0-12,

(11) ##STR00029##
where R5 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups,

(12) ##STR00030##
where R6 is selected from the group consisting of H, alkyl group, alkoxy group, aryl groups,

(13) ##STR00031##
where R7 and R8 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups, NR.sub.9R.sub.10 where R9 and R10 are independently selected from the group consisting of H, alkyl group, alkoxy group, aryl groups.

(14) In one embodiment, the aromatic substituents comprise of heterocycles and fused heterocycles. In other embodiment the process produces a conjugated polymer. In another embodiment the polymerizing of f, g, h and i is regio-regular. In yet another embodiment the polymerizing of f, g, h and i is regio-random.

(15) The polymers produced from the present disclosure can be used as an active layer material or photovoltaic materials in electronic devices or photovoltaic devices such as photodetector devices, solar cell devices, and the like. Photovoltaic devices, including solar cell devices, are generally comprised of laminates of a suitable photovoltaic material between a hole-collecting electrode layer and an electron. In one embodiment the electronic devices are field effect transistors, light emitting devices, and sensors, electrochromic devices and capacitors.

(16) In yet another embodiment, the ratio of

(17) ##STR00032##
in the polymer is around 25:25:25:25.

(18) Different types of polymerization reactions can occur to polymerize f and g with h and i. The current embodiments of these processes are not limited to one specific type of polymerization reaction but can include any currently known polymerization reaction capable of reaction f and g with h and i. Some of these polymerization reactions include:

(19) Stille coupling:

(20) ##STR00033##

(21) Suzuki coupling:

(22) ##STR00034##

(23) Nickel catalyzed

(24) ##STR00035##

(25) Direct arylation

(26) ##STR00036##

(27) In one embodiment, the substituent T can be selected from Me.sub.3Sn, C.sub.6H.sub.12,O.sub.2B, Br or any other substituent that can be used in the polymerization reaction. In another embodiment the substituent T of compound f and g reacts exclusively with substituents Z of compounds h and i.

(28) In one embodiment,

(29) ##STR00037##
is a di-Me3Sn substituted benzo[1,2-b:4,5-b]dithiophene. In another embodiment,

(30) ##STR00038##
is a di-Me3Sn substituted benzo[1,2-b:4,5-b]dithiophene.

(31) Typically, the number average molecular weight of the polymers is in the range of approximately 1000 to 1,000,000, with ideal polymers having a number average molecular weight in the range of about 5000 to 500,000, and some ideal polymers having a number average molecular weight in the range of approximately 20,000 to 200,000. It will be appreciated that molecular weight can be varied to optimize polymer properties and the inventions of the present disclosure cover all molecular weights. For example, lower molecular weight can ensure solubility, while a higher molecular weight can ensure good film-forming properties.

(32) The polymers produced from the present disclosure can be used as photovoltaic materials in photovoltaic devices such as photodetector devices, solar cell devices, and the like. Photovoltaic devices, including solar cell devices, are generally comprised of laminates of a suitable photovoltaic material between a hole-collecting electrode layer and an electron-collecting layer. Additional layers, elements or a substrate may or may not be present.

EXAMPLES

(33) List of acronyms used:

(34) BDT: Benzo[1,2-b:4,5-b]dithiophene

(35) FTT: 3-Fluorothieno[3,4-b]thiophene

(36) FTT(E): 2-ethylhexyl 3-fluorothieno[3,4-b]thiophene-2-carboxylate

(37) FTT(P): propyl 3-fluorothieno[3,4-b]thiophene-2-carboxylate

(38) FTT(N): 3-fluoro-N,N-dihexylthieno[3,4-b]thiophene-2-carboxamide

(39) FTT (K1): 2-ethyl-1-(3-fluorothieno[3,4-b]thiophen-2-yl)hexan-1-one

(40) FTT (K2): 1-(3-fluorothieno[3,4-b]thiophen-2-yl)butan-1-one

(41) PCE: power conversion efficiency

(42) Jsc: short circuit current

(43) Voc: open circuit voltage

(44) PDI: polydispersity index

(45) M.sub.n: number average molecular weight defined by (NiMi)/Ni where Mi is the molecular weight of a chain and Ni is the number of chains of that molecular weight

(46) Soxhlet Extraction: The polymer is washed using a reflux apparatus with different solvents. The solvent and polymer is then heated till the solvent evaporates into a gas, then cools into a liquid. The solvent is then evaporated off and polymer products are produced.

Example 1

(47) P(BDT-FTT(P)), (100% FTT-propyl): Monomers BDT (0.228 g, 0.252 mmol) and FTT(P) (0.101 g, 0.251 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (14 mg), toluene (10 mL) and dimethylformamide (4 mL). The solution was heated to 130 C. and stirred for 36 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=40 kDa and PDI=2.08).

Example 2

(48) P(BDT-FTT(P70)), (70% FTT-propyl, 30% FTT-ethylhexyl): Monomers BDT (0.142 g, 0.157 mmol), FTT(E) (0.022 g, 0.047 mmol) and FTT(P) (0.044 g, 0.109 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (12 mg), toluene (7 mL) and DMF (2.5 mL). The solution was heated to 130 C. and stirred for 24 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=17 kDa and PDI=3.70).

Example 3

(49) P(BDT-FTT(P50)), (50% FTT-propyl, 50% FTT-ethylhexyl): Monomers BDT (0.108 g, 0.119 mmol), FTT(E) (0.028 g, 0.059 mmol) and FTT(P) (0.024 g, 0.059 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (7 mg), toluene (6 mL) and DMF (2 mL). The solution was heated to 130 C. and stirred for 24 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=34 kDa and PDI=3.17).

Example 4

(50) P(BDT-FTT(P30)), (30% FTT-propyl, 70% FTT-ethylhexyl): Monomers BDT (0.080 g, 0.088 mmol), FTT(E) (0.029 g, 0.061 mmol) and FTT(P) (0.011 g, 0.027 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (5 mg), toluene (6 mL) and DMF (3 mL). The solution was heated to 130 C. and stirred for 36 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=63 kDa and PDI=2.96).

Example 5

(51) P(BDT-FTT(P10)), (10% FTT-propyl, 90% FTT-ethylhexyl): Monomers BDT (0.093 g, 0.103 mmol), FTT(E) (0.044 g, 0.093 mmol) and FTT(P) (0.004 g, 0.010 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (6 mg), toluene (6 mL) and DMF (2 mL). The solution was heated to 130 C. and stirred for 24 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=24 kDa and PDI=2.08).

Example 6

(52) PBDT-FTT(E), (100% FTT-ethylhexyl): Monomers BDT (0.115 g) and FTT(E) (0.060 g) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (7 mg) in toluene (4 mL) and DMF (1 mL). The solution was heated to 115 C. and stirred for 96 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=24 kDa and PDI=2.1).

(53) In closing, it should be noted that the discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. At the same time, each and every claim below is hereby incorporated into this detailed description or specification as an additional embodiment of the present invention.

Example 7

(54) P4BDT-FTT(E)).sub.0.25-(BDT-FTT(K1)).sub.0.75) Monomers distannyl-BDT (0.10 g, 0.11 mmol)), dibromo-FTT(E) (13 mg, 0.0275 mmol) and dibromo-FTT(K1) (36.5 mg, 0.0825 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (12.8 mg) in toluene (4.4 mL) and DMF (1.1 mL). The solution was heated to 120 C. and stirred for 48 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=41 kDa and PDI=2.9).

(55) ##STR00039##

Example 8

(56) P((BDT-FTT(E)).sub.0.5-(BDT-FTT(K1)).sub.0.5) Monomers distannyl-BDT (100 mg, 0.11 mmol)), dibromo-FTT(E) (26 mg, 0.055 mmol) and dibromo-FTT(K1) (24 mg, 0.055 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (13 mg) in toluene (4.4 mL) and DMF (1.1 mL). The solution was heated to 120 C. and stirred for 48 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=29.6 kDa and PDI=2.9).

(57) ##STR00040##

Example 9

(58) P((BDT-FTT(E)).sub.0.75-(BDT-FTT(K1)).sub.0.25) Monomers distannyl-BDT (100 mg, 0.11 mmol)), dibromo-FTT(E) (39 mg, 0.0825 mmol) and dibromo-FTT(K1) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (13 mg) in toluene (4.4 mL) and DMF (1.1 mL). The solution was heated to 120 C. and stirred for 48 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=20 kDa and PDI=2.43).

(59) ##STR00041##

Example 10

(60) P((BDT-FTT(E)).sub.0.5-(BDT-FTT(K2)).sub.0.5) Monomers distannyl-BDT (100 mg, 0.11 mmol)), dibromo-FTT(E) (26 mg, 0.055 mmol) and dibromo-FTT(K2) (21 mg, 0.055 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (7 mg) in toluene (4.4 mL) and DMF (1.1 mL). The solution was heated to 120 C. and stirred for 48 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=23 kDa and PDI=1.4).

(61) ##STR00042##

Example 11

(62) P((BDT-FTT(P)).sub.0.5-(BDT-FTT(K1)).sub.0.5) Monomers distannyl-BDT (0.185 g, 0.21 mmol)), dibromo-FTT(P) (42 mg, 0.10 mmol) and dibromo-FTT(K1) (44 mg, 0.10 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (32 mg) in toluene (9 mL) and DMF (3 mL). The solution was heated to 120 C. and stirred for 48 h. The solution was poured into 100 mL methanol and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction by washing subsequently with acetone, hexanes and chloroform. The polymer was recovered in the chloroform fraction (M.sub.n=16 kDa and PDI=1.9).

(63) ##STR00043##

Example 12

(64) P[(BDT1-FTTN)-(BDT2-FTTE)] Monomers distannyl-BDT1 (0.055 mmol), distannyl-BDT2 (0.111 mmol), dibromo-FTTE (39.15 mg, 0.083 mmol) and dibromo-FTTN (43.72 mg, 0.083 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (19.1 mg, 0.017 mmol), toluene (6.6 mL) and DMF (1.65 mL). The reaction mixture was degassed via two freeze-pump-thaw cycles, using liquid nitrogen to freeze the solution. The solution was then heated to 120 C. and stirred for one day under Argon atmosphere. The reaction mixture was cooled to room temperature, poured into methanol (70 mL), and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction, washing sequentially with acetone, hexanes, and chloroform. The polymer was recovered in the chloroform fraction (110 mg, 71% yield).

Example 13

(65) P[(BDT1-FTTN)-(BDT2-FTTP)] Monomers distannyl-BDT1 (0.055 mmol), distannyl-BDT2 (0.111 mmol), dibromo-FTTP (33.34 mg, 0.083 mmol) and dibromo-FTTN (43.72 mg, 0.083 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (19.1 mg, 0.017 mmol), toluene (6.6 mL) and DMF (1.65 mL). The reaction mixture was degassed via two freeze-pump-thaw cycles, using liquid nitrogen to freeze the solution. The solution was then heated to 120 C. and stirred for one day under Argon atmosphere. The reaction mixture was cooled to room temperature, poured into methanol (70 mL), and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction, washing sequentially with acetone, hexanes, and chloroform. The polymer was recovered in the chloroform fraction (100 mg, 67% yield).

Example 14

(66) P[(BDT1-FTTN)-(BDT2-FTTK.sub.(EH))] Monomers distannyl-BDT1 (0.055 mmol), distannyl-BDT2 (0.111 mmol), dibromo-FTTK.sub.(EH) (36.66 mg, 0.083 mmol) and dibromo-FTTN (43.72 mg, 0.083 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (19.1 mg, 0.017 mmol), toluene (6.6 mL) and DMF (1.65 mL). The reaction mixture was degassed via two freeze-pump-thaw cycles, using liquid nitrogen to freeze the solution. The solution was then heated to 120 C. and stirred for one day under Argon atmosphere. The reaction mixture was cooled to room temperature, poured into methanol (70 mL), and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction, washing sequentially with acetone, hexanes, and chloroform. The polymer was recovered in the chloroform fraction (124 mg, 81% yield).

Example 15

(67) P[(BDT1-FTTN)-(BDT2-FTTK.sub.(B))] Monomers distannyl-BDT1 (0.060 mmol), distannyl-BDT2 (0.119 mmol), dibromo-FTTK.sub.(B) (34.56 mg, 0.090 mmol) and dibromo-FTTN (47.2 mg, 0.090 mmol) were combined in a Schlenk flask with Pd(PPh.sub.3).sub.4 (19.1 mg, 0.017 mmol), toluene (7.16 mL) and DMF (1.8 mL). The reaction mixture was degassed via two freeze-pump-thaw cycles, using liquid nitrogen to freeze the solution. The solution was then heated to 120 C. and stirred for one day under Argon atmosphere. The reaction mixture was cooled to room temperature, poured into methanol (70 mL), and the polymer was collected by filtration. The polymer was purified by Soxhlet extraction, washing sequentially with acetone, hexanes, and chloroform. The polymer was recovered in the chloroform fraction (107 mg, 67% yield).

(68) Device Fabrication and Measurement

(69) ZnO sol-gel was prepared by dissolving zinc acetate dihydrate (220 mg, 1 mmol) and ethanolamine (62 mg, 1 mmol) into 2-methoxyethanol (2 mL) and stirred for 1 h in air. ITO-coated glass substrates were washed with detergent (15 min), DI water (215 min), acetone (15 min), and isopropanol (15 min) in an ultrasonication bath. The substrates were placed in a vacuum oven at 80 C. for 2 h and placed in a UV-ozone cleaner for 15 minutes. After filtration with a 0.2 m PVDF syringe filter, ZnO sol-gel was spin-coated onto the top of the ITO substrate at 5000 rpm for 30 s (acceleration 5000 rpm). The substrate was annealed at 170 C. in air for 15 min and taken into glove box for deposition of the active layer. At the same time, 10 mg of P(BDT-FTT) and 16 mg of PC.sub.70BM were mixed in ortho-xylene (1 mL) and stirred at 100 C. for 12 h. Diiodooctane (25 L) was added to the solution and stirred for an additional 1 h, followed by filtration through a 0.45 m PTFE syringe filter. Afterwards, the solution was coated on the substrate at 1,800, 2,000, and 2,200 rpm for 20 s. The substrate was solvent annealed inside of glass dishes for 1 h. After solvent annealing, the substrate was scratched at the edge to expose the ITO layer for the metal deposition. The substances were placed in the metal evaporator, and 14 nm of MoO.sub.3 and 100 nm of Ag were deposited. The deposition speed for the MoO.sub.3 was 0.5 /s. The deposition speed for Ag started at 0.5 /s until 5 nm was deposited. Afterward, the speed increased to 1-1.5 /s until 100 nm was deposited. The devices were encapsulated using UV-curable epoxy and a cover glass, and exposed to UV cure for 10 min.

(70) The current density-voltage (J-V) curves were measured using a Keithley 2400 source meter. The photocurrent was measured under AM 1.5 G illumination at 100 mW/cm.sup.2 under Newport Thermal Oriel 91192 1000W solar simulator (44 beam size). The light intensity was calibrated by a mono-silicon detector (with KG-5 visible color filter) calibrated by National Renewable Energy Laboratory to minimize spectral mismatch.

(71) Table 1 depicts some of the solar cell performance of the polymers in this study.

(72) TABLE-US-00001 Fill % FTT V.sub.oc J.sub.sc Factor PCE R.sub.s R.sub.sh Examples propyl (V) (mA/cm.sup.2) (%) (%) ( .Math. cm.sup.2) () 1 100% 0.740 17.3 62.4 7.99 4.6 5723 2 70% 0.75 16.5 65.0 8.07 4.6 9412 3 50% 0.77 16.5 70.1 8.90 3.4 9286 4 30% 0.76 16.1 61.1 7.48 5.0 5547 5 10% 0.80 14.5 65.5 7.60 5.2 7567 6 0% 0.80 16.0 68.6 8.74 4.1 10504

(73) Table 2 depicts the solar cell performance of polymers from Examples 7-9.

(74) TABLE-US-00002 FTT(E): J.sub.sc Fill FTT(K1) V.sub.oc (mA/ Factor PCE R.sub.s R.sub.sh Polymer ratio (V) cm.sup.2) (%) (%) ( .Math. cm.sup.2) ( .Math. cm.sup.2) Example 0.25:0.75 0.81 15.89 59.95 7.72 7.25 620 7 8 0.5:0.5 0.77 17.29 64.79 8.26 5.19 779 9 0.75:0.25 0.79 16.83 67.84 9.04 4.34 815

(75) Table 3 depicts the solar cell performance of polymers from Example 10.

(76) TABLE-US-00003 FTT(E): J.sub.sc Fill FTT(K2) V.sub.oc (mA/ Factor PCE R.sub.s R.sub.sh Polymer ratio (V) cm.sup.2) (%) (%) ( .Math. cm.sup.2) ( .Math. cm.sup.2) Example 0.5:0.5 0.79 17.3 68 9.30 2.8 956 10

(77) Table 4 depicts the solar cell performance of polymers from Example 11.

(78) TABLE-US-00004 FTT(P): J.sub.sc Fill FTT(K1) V.sub.oc (mA/ Factor PCE R.sub.s R.sub.sh Polymer ratio (V) cm.sup.2) (%) (%) ( .Math. cm.sup.2) ( .Math. cm.sup.2) Example 0.5:0.5 0.81 15.77 63.49 8.11 4.97 713 11

Example 12

(79) The polymer derivative of example 3 was further optimized in devices. A device structure was used which included a [6,6]-phenyl C61 butyric acid 2-hydroxyethyl ester (PCBE-OH) doped ZnO film as a interfacial layer. The resulting solar cell performance is depicted in the figure and Table 2 below. The V.sub.oc for this device slightly higher compared to the above fabrication method, and the J.sub.sc increases to 17.4 mA/cm.sup.2.

(80) TABLE-US-00005 TABLE 5 J.sub.sc Fill Device V.sub.oc (mA/ Factor PCE R.sub.s R.sub.sh Polymer Structure (V) cm.sup.2) (%) (%) ( .Math. cm.sup.2) () Example ITO/ZnO/ 0.79 17.4 69.0 9.46 3.7 8311 3 ZnOPCBOH/ active layer/ MoO.sub.3/Ag

(81) TABLE-US-00006 TABLE 6 J.sub.sc R.sub.s R.sub.sh V.sub.oc (mA/ FF PCE ( ( Polymer (V) cm.sup.2) (%) (%) cm.sup.2) cm.sup.2) Example P[(BDT1-FTTN)- 0.769 15.7 71.1 8.59 3.96 1160 12 (BDT2-FTTE)] Example P[(BDT1-FTTN)- 0.743 13.9 67.6 6.96 6.30 1323 13 (BDT2-FTTP)] Example P[(BDT1-FTTN)- 0.809 11.5 59.9 5.55 8.50 759 14 (BDT2-FTTK.sub.(EH))] Example P[(BDT1-FTTN)- 0.769 14.1 68.4 7.42 5.75 1690 15 (BDT2-FTTK.sub.(B))] V.sub.ocopen circuit voltage; J.sub.scshort circuit current; FFfill factor; PCEpower conversion efficiency; R.sub.sseries resistance; R.sub.shshunt resistance

(82) In closing, it should be noted that the discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. At the same time, each and every claim below is hereby incorporated into this detailed description or specification as an additional embodiment of the present invention.

(83) Although the systems and processes described herein have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the invention as defined by the following claims. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the invention that are not exactly as described herein. It is the intent of the inventors that variations and equivalents of the invention are within the scope of the claims while the description, abstract and drawings are not to be used to limit the scope of the invention. The invention is specifically intended to be as broad as the claims below and their equivalents.