Photovoltaic cell with benzodithiophene-containing polymer

1. An article, comprising:

a first electrode,

a second electrode, and

a photoactive material disposed between the first and second electrodes, the photoactive material comprising a polymer including a first monomer repeat unit, the first monomer repeat unit comprising a benzodithiophene moiety substituted with at least one electron withdrawing group selected from COR, COOR, CO—N(RR′), C 1 -C 20 perfluoroalkyl, or SO 3 R, in which each of R or R′, independently, is H, C 1 -C 24 alkyl, aryl, heteroaryl, C 3 -C 24 cycloalkyl, or C 3 -C 24 heterocycloalkyl;

wherein the article is configured as a photovoltaic cell.

2. The article of claim 1 , wherein the electron withdrawing group is COOC 8 H 17 , COOC 10 H 21 , COOC 12 H 25 , COOC 14 H 29 , COOC 16 H 33 , CO—N(C 4 H 9 ) 2 , or CO—N(C 8 H 17 ) 2 .

3. The article of claim 1 , wherein the benzodithiophene moiety is substituted with two electron withdrawing groups.

4. The article of claim 1 , wherein the first monomer repeat unit comprises a benzodithiophene moiety of formula (1):

in which each of R 1 and R 2 , independently, is H or an electron withdrawing group, and each of R 3 and R 4 , independently, is H, halo, C 1 -C 24 alkyl, C 1 -C 24 alkoxy, aryl, heteroaryl, C 3 -C 24 cycloalkyl, C 3 -C 24 heterocycloalkyl, COR″, or COOR″, in which R″ is H, C 1 -C 24 alkyl, aryl, heteroaryl, C 3 -C 24 cycloalkyl, or C 3 -C 24 heterocycloalkyl.

5. The article of claim 4 , wherein each of R 1 and R 2 , independently, is COR, COOR, CO—N(RR′), C 1 -C 20 perfluoroalkyl, CN, or SO 3 R, in which each of R or R′, independently, is H, C 1 -C 24 alkyl, aryl, heteroaryl, C 3 -C 24 cycloalkyl, or C 3 -C 24 heterocycloalkyl.

6. The article of claim 5 , wherein the first monomer repeat unit comprises a benzodithiophene moiety of formula (1), in which each of R 1 and R 2 , independently, is COR, COOR, or CO—N(RR′).

7. The article of claim 6 , wherein each of R 1 and R 2 is COOC 8 H 17 , COOC 10 H 21 , COOC 12 H 25 , COOC 14 H 29 , COOC 16 H 33 , CO—N(C 4 H 9 ) 2 , or CO—N(C 8 H 17 ) 2 , and each of R 3 and R 4 is H.

8. The article of claim 1 , wherein the polymer further comprises a second monomer repeat unit different from the first monomer repeat unit.

9. The article of claim 8 , wherein the second monomer repeat unit comprises a benzothiadiazole moiety.

10. The article of claim 9 , wherein the second monomer repeat unit comprises a benzothiadiazole moiety of formula (4):

wherein

each of X and Y, independently, is CH 2 , O, or S;

each of R 1 and R 2 , independently, is H, COR, COOR, CO—N(RR′), C 1 -C 20 perfluoroalkyl, CN, or SO 3 R, in which each of R or R′, independently, is H, C 1 -C 24 alkyl, aryl, heteroaryl, C 3 -C 24 cycloalkyl, or C 3 -C 24 heterocycloalkyl; and

each of R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 , independently, is H, halo, C 1 -C 24 alkyl, C 1 -C 24 alkoxy, aryl, heteroaryl, C 3 -C 24 cycloalkyl, C 3 -C 24 heterocycloalkyl, COR″, or COOR″, in which R″ is H, C 1 -C 24 alkyl, aryl, heteroaryl, C 3 -C 24 cycloalkyl, or C 3 -C 24 heterocycloalkyl.

11. The article of claim 10 , wherein the second monomer repeat unit comprises a benzothiadiazole moiety of formula (4).

12. The article of claim 10 , wherein the polymer further comprises a third monomer repeat unit different from the first and second monomer repeat units.

13. The article of claim 12 , wherein the third monomer repeat unit comprises a thiazole moiety or a thiophene moiety.

14. The article of claim 13 , wherein the third monomer repeat unit comprise a thiazole moiety of formula (18) or a thiophene moiety of formula (24):

in which each of R 5 and R 6 , independently, is H, halo, C 1 -C 24 alkyl, C 1 -C 24 alkoxy, aryl, heteroaryl, C 3 -C 24 cycloalkyl, C 3 -C 24 heterocycloalkyl, COR″, or COOR″, in which R″ is H, C 1 -C 24 alkyl, aryl, heteroaryl, C 3 -C 24 cycloalkyl, or C 3 -C 24 heterocycloalkyl.

15. The article of claim 14 , wherein R 5 is H, C 1 -C 24 alkyl, COR″, or COOR″, and R 6 is H or halo.

16. The article of claim 15 , wherein R 5 is H, Cl, C 6 H 13 , C 8 H 17 , C 14 H 29 , COOC 6 H 13 , COC 13 H 27 , or COOC 14 H 29 , and R 6 is H or Cl.