Polymeric Blends and Related Optoelectronic Devices
Disclosed are all-polymer blends including an electron-acceptor polymer and an electron-donor polymer, capable of providing improved device performance, for example, as measured by power conversion efficiency, when used in photovoltaic cells.
1 . 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 a copolymer comprising an aromatic fused-ring diimide unit in its backbone, and wherein the electron-donor polymer is a copolymer comprising one or more thienyl or thienyl units and at least one electron-poor unit in its backbone.
2 . The device of claim 1 , 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 an optionally substituted fused ring moiety;
R 1 and R 1′ are identical or different and independently are selected from the group consisting of a C 1-30 alkyl group, a C 2-30 alkenyl group, a C 1-30 haloalkyl group, a C 6-20 aryl group and a 5-14 membered heteroaryl group, wherein the C 6-20 aryl group and the 5-14 membered heteroaryl group optionally are substituted with a C 1-30 alkyl group, a C 2-30 alkenyl group, or a C 1-30 haloalkyl group;
M a and M a′ 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) R 1′ is different from R 1 , or (c) M a′ is different from M a .
3 . The device of claim 2 , wherein π-1 and π-1′ independently are selected from the group consisting of:
4 . The device of claim 2 , wherein the electron-acceptor polymer is represented by Formula 3 or 4:
wherein:
R′ and R″ are identical or different and independently are selected from the group consisting of H, F, Cl, —CN, and -L-R, wherein L, at each occurrence, independently is selected from the group consisting of —O—, —S—, —C(O), —C(O)O—, and a covalent bond; and R, at each occurrence, independently is selected from the group consisting of a C 6-20 alkyl group, a C 6-20 alkenyl group, and a C 6-20 haloalkyl group;
m and m′ independently are 1, 2, 3, 4, 5 or 6; and
π-1, π-1′, R 1 , R 1′ , p, and q are as defined in claim 5 .
5 . The device of claim 2 , wherein the electron-acceptor polymer is represented by Formula 5, 6, 7, or 8:
wherein R 1 , R 1′ , p, q, and n are as defined in claim 5 .
6 . The device of claim 2 , wherein R′ and R 1′ are selected from the group consisting of a branched C 3-20 alkyl group, a branched C 4-20 alkenyl group, and a branched C 3-20 haloalkyl group.
7 . The device of claim 6 , wherein R 1 and R 1′ are selected from the group consisting of:
8 . The device of claim 1 , wherein the electron-donor polymer has an alternating push-pull structure represented by formula 9:
*D-A* (9),
wherein the donor subunit (D) comprises a bridged dithiophene moiety selected from the group consisting of a benzodithiophene moiety, a naphthodithiophene moiety, a thienodithiophene moiety, and a pyridodithiophene moiety; the acceptor subunit (A) comprises an electron-poor conjugated moiety; and either the donor subunit (D) or the acceptor subunit (A) comprises one or more thienyl groups.
9 . The device of claim 8 , wherein the donor subunit (D) comprises a bridged dithiophene moiety of the formula:
wherein R a , at each occurrence, independently is selected from the group consisting of -L′-R b , -L′-Ar′, and -L′-Ar′-Ar′, wherein L′ is selected from the group consisting of —O—, —S—, and a covalent bond; R b is selected from the group consisting of a C 3-40 alkyl group, a C 3-40 alkenyl group, and a C 3-40 haloalkyl group; and Ar′, at each occurrence, independently is a 5-14 membered heteroaryl group optionally substituted with 1-2 R b groups.
10 . The device of claim 8 , wherein the donor subunit (D) comprises a bridged dithiophene moiety selected from the group consisting of:
where R b , at each occurrence, is a linear or branched C 5-40 alkyl group.
11 . The device of claim 8 , wherein the donor subunit (D) comprises a bridged dithiophene moiety selected from the group consisting of:
is selected from the group consisting of:
each of which optionally is substituted with 1-2 R b groups, and R b , at each occurrence, independently is a C 3-40 alkyl group.
12 . The device of claim 8 , wherein the acceptor subunit (A) is represented by the formula:
wherein δ represents the electron-poor conjugated moiety, and R c , at each occurrence, is H or R, wherein R, at each occurrence, independently is selected from the group consisting of a C 6-20 alkyl group, a C 6-20 alkenyl group, and a C 6-20 haloalkyl group.
13 . The device of claim 12 , wherein the electron-poor conjugated moiety (δ) is an 8-14 membered polycyclic heteroaryl moiety comprising either at least one ring that has two or more heteroatoms selected from N and S, and/or at least one ring that is substituted with one or more electron-withdrawing groups selected from the group consisting of F, Cl, an oxo group, a carbonyl group, a carboxylic ester group, and a sulfonyl group.
14 . The device of claim 12 , wherein the electron-poor conjugated moiety (δ) is selected from the group consisting of:
wherein R d , at each occurrence, independently is selected from a C 3-40 alkyl group, a C 3-40 alkenyl group, and a C 3-40 haloalkyl group; and R f , at each occurrence, independently is selected from the group consisting of H, F, Cl, —CN, —S(O) 2 —C 1-20 alkyl, —C(O)—OC 1-20 alkyl, —C(O)—C 1-20 alkyl, a C 1-20 alkyl group, a C 2-20 alkenyl group, a C 1-20 alkoxy group, a C 1-20 alkylthio group, and a C 1-20 haloalkyl group.
15 . The device of claim 1 , wherein the electron donor polymer is a random copolymer having the formula 13 or 14:
wherein:
R a , at each occurrence, is selected from the group consisting of -L′-R b , -L′-Ar′, and -L′-Ar′-Ar′, wherein L′ is selected from the group consisting of —O—, —S—, and a covalent bond; R b is selected from the group consisting of a C 3-40 alkyl group, a C 3-40 alkenyl group, and a C 3-40 haloalkyl group; and Ar′, at each occurrence, independently is a 5-14 membered heteroaryl group optionally substituted with 1-2 R b groups;
R c , at each occurrence, is H or R, where R, at each occurrence, independently is selected from the group consisting of a C 6-20 alkyl group, a C 6-20 alkenyl group, and a C 6-20 haloalkyl group;
δ is selected from the group consisting of:
wherein R d , at each occurrence, independently is selected from a C 3-40 alkyl group, a C 3-40 alkenyl group, and a C 3-40 haloalkyl group; and R f , at each occurrence, independently is selected from the group consisting of H, F, Cl, —CN, —S(O) 2 —C 1-20 alkyl, —C(O)—OC 1-20 alkyl, —C(O)—C 1-20 alkyl, a C 1-20 alkyl group, a C 2-20 alkenyl group, a C 1-20 alkoxy group, a C 1-20 alkylthio group, and a C 1-20 haloalkyl group;
x and y independently are a real number, wherein 0.1≦x≦0.9, 0.1≦y≦0.9, and the sum of x and y is about 1; and
n is an integer in the range of 2 to 5,000.
16 . The device of claim 14 , wherein R d , at each occurrence, independently is a linear or branched C 6-20 alkyl group; and R f , at each occurrence, independently is selected from H, F, Cl, C(O)R e , C(O)OR e , and S(O) 2 R e ; where R e , at each occurrence, independently is a linear or branched C 6-20 alkyl group.
17 . The device of claim 5 , wherein the electron donor polymer is an alternating copolymer selected from the group consisting of formula 15-24, wherein R b , at each occurrence, is a linear or branched C 3-40 alkyl group; R e , at each occurrence, is H or a C 6-20 alkyl group; and n is an integer in the range of 5 to 5,000.
18 . The device of claim 5 , wherein the electron donor polymer is a random copolymer selected from the group consisting of formula 25-42, wherein R b , at each occurrence, is a linear or branched C 3-40 alkyl group; R, at each occurrence, is a C 6-20 alkyl group; x and y independently are a real number, wherein 0.1≦x≦0.9, 0.1≦y≦0.9 (0.2≦x≦0.8, 0.2≦y≦0.8), and the sum of x and y is about 1; and n is an integer in the range of 5 to 5,000.
19 . The device of claim 5 , wherein the electron donor polymer is an alternating copolymer selected from the group consisting of formula 43-56, wherein R b , R d , R e , at each occurrence, independently is a linear or branched C 3-40 alkyl group; R c , at each occurrence, is H or a C 6-20 alkyl group; R f , at each occurrence, independently is selected from H, F, Cl, C(O)R e , C(O)OR e , and S(O) 2 R e ; where R e , at each occurrence, independently is a linear or branched C 6-20 alkyl group; r is 0 or 1; and n is an integer in the range of 5 to 5,000.
20 . The device of claim 1 configured as an organic photovoltaic device comprising an anode, a cathode, optionally one or more anode interlayers, optionally one or more cathode interlayers, and in between the anode and the cathode the photoactive layer.