Polymeric blends and related optoelectronic devices

An optoelectronic device comprising a first electrode, a second electrode, and a photoactive layer disposed between the first and second electrodes, the photoactive layer comprising a polymer-polymer blend semiconductor material, the polymer-polymer blend semiconductor material comprising an electron-donor polymer and an electron-acceptor polymer, wherein:

• the electron-acceptor polymer is represented by Formula 1 or 2:
• wherein:
• π−1 and π−1′ are identical or different and independently are selected from the group consisting of:
• R1 and R1′ are identical or different and independently are selected from the group consisting of a C1-30 alkyl group, a C2-30 alkenyl group, a C1-30 haloalkyl group, a C6-20 aryl group and a 5-14 membered heteroaryl group, wherein the C6-20 aryl group and the 5-14 membered heteroaryl group optionally are substituted with a C1-30 alkyl group, a C2-30 alkenyl group, or a C1-30 haloalkyl group;
• Ma and Ma′ are identical or different and independently are a repeat unit comprising one or more conjugated moieties that does not include a rylene diimide;
• p and q independently are a real number, wherein 0.1≦p≦0.9, 0.1≦q≦0.9, and the sum of p and q is about 1;
• and
• n is an integer in the range of 2 to 5,000;
• provided that at least one of the following is true:
• (a) π−1′ is different from π−1, (b) R1′ is different from R1, or (c) Ma′ is different from Ma;
• and
• the electron-donor polymer is an alternating copolymer selected from the group consisting of:
• wherein Rb, at each occurrence, is a linear or branched C3-40 alkyl group;
• Rc, at each occurrence, is H or a C6-20 alkyl group;
• and n is an integer in the range of 5 to 5,000.