Organic electronic devices and polymers, including photovoltaic cells and diketone-based polymers
View Patent ↗Polymers which can be used in p-type materials for organic electronic devices and photovoltaic cells. Compounds, monomers, dimers, trimers, and polymers comprising: Good photovoltaic efficiency and lifetime can be achieved. The R group can provide solubility, environmental stability, and fine tuning of spectroscopic and/or electronic properties. Different polymer microstructures can be prepared which encourage multiple band gaps and broad and strong absorptions. The carbonyl can interact with adjacent thiophene rings to provide backbone with rigidity, induce planarity, and reduce and/or eliminate intramolecular chain twisting defects. Polymers comprising benzodithiophene and/or benzothiadiazole structures can show particularly high performance.
1. A device comprising:
at least one cathode;
at least one anode;
at least one photovoltaic active layer disposed between the cathode and anode and comprising at least one p-type material and at least one n-type material, wherein the p-type material comprises at least one polymer comprising a donor-acceptor structure, comprising a first acceptor backbone moiety:
wherein R comprises optionally substituted alkyl, optionally substituted linear alkyl, optionally substituted branched alkyl, optionally substituted aryl, optionally substituted alkylaryl, optionally substituted arylalkyl, optionally substituted alkoxy, or optionally substituted aryloxy, and
wherein the donor comprises at least one benzodithiophene structure, and the polymer comprises at least one second acceptor other than (I), wherein the second acceptor other than (I) comprises a benzothiadiazole structure, wherein the polymer is represented by:
wherein the R groups of the benzodithiophene structures are alkyl groups, and wherein the R group of the formula (I) structure is as previously defined, and wherein n is adapted to provide the polymer with a number average molecular weight of at least 10,000, and wherein x and y are adapted to provide the polymer with a molar amount of 55-75% of the first acceptor having the formula (I) structure and a molar amount of 25-45% of the second acceptor having the benzothiadiazole structure relative to the total molar amount of the combined first and second structure.
2. The device of claim 1 , wherein the molar amount of the first acceptor is about 65%, and the molar amount of the second acceptor is about 35%, relative to the total molar amount of the combined first and second acceptor structure.
3. The device of claim 1 , wherein the benzodithiophene structure comprises at least one C6-C12 branched alkyl structure.
4. The device of claim 1 , wherein the R group of Formula (I) is a C6-C12 branched alkyl structure.
5. The device of claim 1 , wherein the polymer is a random polymer.
6. The device of claim 1 , wherein the polymer is soluble in chloroform.
7. The device of claim 1 , wherein the device has a power conversion efficiency of at least 6%.
8. The device of claim 1 , wherein the device has an open circuit voltage of at least 0.9 V.
9. The device of claim 1 , wherein the device has a power conversion efficiency of at least 6%, and an open circuit voltage of at least 0.9 V.
10. The device of claim 1 , wherein the device has at least one hole transport layer disposed next to the active layer.
11. The device of claim 1 , wherein the device has at least one hole transport layer disposed next to the active layer which comprises at least two polymers.
12. The device of claim 1 , wherein the device has at least one hole transport layer disposed next to the active layer which comprises at least two polymers, wherein at least one polymer is a polythiophene and at least one polymer different from the other is a fluorinated polymer.
13. The device of claim 1 , wherein the device has at least one hole transport layer disposed next to the active layer, wherein the hole transport layer comprises at least one sulfonated regioregular polythiophene.
14. The device of claim 1 , wherein the active layer is annealed.
15. The device of claim 1 , wherein the active layer is thermally annealed.
16. The device of claim 1 , wherein the active layer is solvent annealed.
17. The device of claim 1 , wherein the active layer is annealed with use of an electric field.
18. The device of claim 1 , wherein the weight ratio of p-type and n-type material is about 1:1 to 1:3.
19. The device of claim 1 , wherein the active layer is formed by deposition of an ink comprising at least one fluorinated solvent.
20. The device of claim 1 , wherein the polymer is represented by:
wherein R is defined as in claim 1 .
21. A composition comprising at least one polymer comprising a donor-acceptor structure, comprising a first acceptor backbone moiety:
wherein R comprises optionally substituted alkyl, optionally substituted linear alkyl, optionally substituted branched alkyl, optionally substituted aryl, optionally substituted alkylaryl, optionally substituted arylalkyl, optionally substituted alkoxy, or optionally substituted aryloxy, and
wherein the donor comprises at least one benzodithiophene structure, and the polymer comprises at least one second acceptor other than (I), wherein the second acceptor other than (I) is a benzothiadiazole, wherein the polymer is represented by:
wherein the R groups of the benzodithiophene structures are alkyl groups, and wherein the R group of the formula (I) structure is as previously defined and wherein n is adapted to provide the polymer with a number average molecular weight of at least 10,000, and wherein x and y are adapted to provide the polymer with a molar amount of 55-75% of the first acceptor having the formula (I) structure and a molar amount of 25-45% of the second acceptor having the benzothiadiazole structure relative to the total molar amount of the combined first and second structure.
22. The composition of claim 21 , wherein the composition further comprises at least one solvent.
23. The composition of claim 21 , wherein the composition further comprises at least one n-type material.
24. The composition of claim 21 , wherein the polymer is represented by:
wherein R is defined as in claim 21 .
25. The composition of claim 21 , wherein the molar amount of the first acceptor is about 65%, and the molar amount of the second acceptor is about 35%, relative to the total molar amount of the combined first and second acceptor structure.
26. The composition of claim 21 , wherein the benzodithiophene structure comprises at least one C6-C12 branched alkyl structure.
27. The composition of claim 21 , wherein the R group of Formula (I) is a C6-C12 branched alkyl structure.
28. The composition of claim 21 , wherein the polymer is a random polymer.
29. The composition of claim 21 , wherein the polymer is soluble in chloroform.
30. The composition of claim 23 , wherein the polymer is a p-type material, and the weight ratio of p-type and n-type material is about 1:1 to 1:3.