Conjugated polymers and their use in optoelectronic devices
The present invention relates to certain polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The present compounds can provide improved device performance, for example, as measured by power conversion efficiency, fill factor, open circuit voltage, field-effect mobility, on/off current ratios, and/or air stability when used in photovoltaic cells or transistors. The present compounds can have good solubility in common solvents enabling device fabrication via solution processes.
1. An organic photovoltaic device comprising an anode, a cathode, and in between the anode and the cathode a photoactive layer, the photoactive layer comprising an electron-donor compound and an electron-acceptor compound, wherein the electron-donor compound is a polymer of the formula:
wherein
R 1 is selected from the group consisting of a C 1-40 alkyl group, a C 2-40 alkenyl group, and a C 1-40 haloalkyl group; and R 4 , at each occurrence, independently is selected from the group consisting of a -L-C 1 -40 alkyl group, a -L-C 2-40 alkenyl group, and a -L-C 1-40 haloalkyl group, wherein L, at each occurrence, is selected from the group consisting of O, S, and a covalent bond, and each of the C 1-40 alkyl group and the C 2-40 alkenyl group optionally is substituted with 1-10 substituents independently selected from the group consisting of a halogen, —CN, —NH 2 , —NH(C 1-20 alkyl), —N(C 1-20 alkyl) 2 , —SiH 3 , —SiH(C 1-20 alkyl) 2 —SiH 2 (C 1-20 alkyl), —Si(C 1-20 alkyl) 3 , an —O—C 1-20 alkyl group, and an —S—C 1-20 alkyl group.
2. The device of claim 1 , wherein R l is selected from the group consisting of a branched C 3-40 alkyl group, a branched C 4-40 alkenyl group, and a branched C 3-40 haloalkyl group.
3. The device of claim 1 , wherein R 4 , at each occurrence, independently is selected from the group consisting of a -L-C 6-40 alkyl group, a -L-C 6 -40 alkenyl group, and a -L-C 6-40 haloalkyl group, wherein L, at each occurrence, is selected from the group consisting of O, S, and a covalent bond.
4. The device of claim 1 , wherein the polymer has a molecular weight in the range of about 3,000 to about 300,000.
5. The device of claim 1 , wherein the photoactive component comprises a blend material comprising the electron-donor compound and the electron-acceptor compound.
6. The device of claim 1 , wherein the electron-acceptor compound is [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM) or [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM).
7. The device of claim 1 , wherein the device comprises one or more cathode interlayers.
8. The device of claim 1 , wherein the device comprises one or more anode interlayers.
9. The device of claim 1 , wherein the device has a power conversion efficiency of at least about 5%.
10. The device of claim 1 , wherein the device has a power conversion efficiency of at least about 8%.
11. The device of claim 1 , wherein the device has a power conversion efficiency of at least about 9%.