Polymeric blends and related optoelectronic devices

Abstract

The present invention relates to 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 represented by Formula 1: 
       
         
           
           
               
               
           
         
         wherein: 
         π-1 is 
       
       
         
           
           
               
               
           
         
         R 1  is 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  is a repeat unit comprising one or more conjugated moieties that does not include a rylene diimide; and 
         n is an integer in the range of 2 to 5,000; and 
       
       the electron-donor polymer has an alternating push-pull structure represented by:
   * D - A*,  
 
 wherein: 
 the donor subunit (D) comprises a benzodithiophene 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 or branched alkyl group; 
       
       and the acceptor subunit (A) is represented by the following moiety: 
       
         
           
           
               
               
           
         
       
       wherein 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. 
     
     
         2 . The device of  claim 1 , wherein the electron-acceptor polymer is represented by Formula 3: 
       
         
           
           
               
               
           
         
       
       wherein:
 R′ is 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 is 1, 2, 3, 4, 5 or 6. 
 
     
     
         3 . The device of  claim 1 , wherein the electron-acceptor polymer is represented by Formula 6: 
       
         
           
           
               
               
           
         
       
     
     
         4 . The device of  claim 1 , wherein R 1  is 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. 
     
     
         5 . The device of  claim 4 , wherein R 1  is selected from the group consisting of: 
       
         
           
           
               
               
           
         
       
     
     
         6 . The device of  claim 1 , wherein the electron donor polymer is an alternating copolymer selected from the group consisting of: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       wherein R b , at each occurrence, is a linear or branched C 3-40  alkyl group; R c , 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. 
     
     
         7 . The device of  claim 1 , wherein the electron donor polymer is a random copolymer selected from the group consisting of: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       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. 
     
     
         8 . 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.