Stilbene and fused stilbene derivatives as solar cell dyes

A solar cell dye for use in a DSSC, wherein the solar cell dye is a compound of formula I:

• wherein
• R6 is selected from the group consisting of —NR3R4, —R3, —OR3 and halo;
• R5 is —(CR═CR—)n(CR═CR2—)R1;
• n is an integer from 0 to 10;
• R1 and R2 are independently selected from the group consisting of —H, —CN, —COOR, CONHR, CON(H)OR, —SO3R, —SO2R —OSO3R, —PO3HR, and —OPO3HR, further wherein at least one of R1 and R2 is not —H;
• each R is independently selected from —H and C1-6 linear or branched alkyl;
• and
• R3 and R4 are independently selected from the group consisting of H, substituted or unsubstituted linear or branched C1-C10 alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted C6-C10 aryl, substituted or unsubstituted C5-C10 heteroaryl, substituted or unsubstituted C5-C10 cycloalkyl, and substituted or unsubstituted C5-C10 heterocycloalkyl;
• or R3 and R4 attached to their N together form a ring that is substituted or unsubstituted C5-C10 heterocycloalkyl, provided that
• if n=0, and R3 and R4 are both:
• (a) H;
• (b) substituted or unsubstituted linear or branched C1-C10 alkyl;
• or (c) substituted or unsubstituted phenyl or C6-C10 aryl, then R1 and R2 are not both selected from the group consisting of —H, —CN, —COOR, and —CONHR.