Fullerene surfactants and their use in polymer solar cells

Abstract

Fullerene surfactant compounds useful as interfacial layer in polymer solar cells to enhance solar cell efficiency. Polymer solar cell including a fullerene surfactant-containing interfacial layer intermediate cathode and active layer.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A photovoltaic device comprising:
 (a) a first electrode;   (b) an active layer disposed on a surface of the first electrode;   (c) a layer comprising a compound disposed on a surface of the active layer opposite the first electrode, wherein the compound comprises
 (i) a fullerene group; 
 (ii) one or more cationic nitrogen centers covalently coupled to the fullerene group; 
 (iii) one or more hydrophilic groups covalently coupled to the fullerene group; 
 (iv) one or more counter ions associated with the cationic nitrogen center; and 
   (d) a second electrode disposed on a surface of the layer comprising the compound opposite the active layer.   
     
     
         2 . The photovoltaic device of  claim 1 , wherein the fullerene group is selected from the group consisting of C 60 , C 70 , C 76 , C 78 , C 82 , C 84 , and C 92  fullerene groups. 
     
     
         3 . The photovoltaic device of  claim 1 , wherein the cationic nitrogen center is a quaternary amine group. 
     
     
         4 . The photovoltaic device of  claim 1 , wherein the hydrophilic group is a polyether group. 
     
     
         5 . The photovoltaic device of  claim 4 , wherein the polyether group is a polyalkene oxide group. 
     
     
         6 . The photovoltaic device of  claim 5 , wherein the polyalkene oxide group is a polyethylene oxide group having the formula —(CH 2 CH 2 O) n —, where n is from 1 to about 20. 
     
     
         7 . The photovoltaic device of  claim 1 , wherein the compound further comprises an anionic center. 
     
     
         8 . The photovoltaic device of  claim 7 , wherein the anionic center is selected from the group consisting of sulfonate (SO 3   2− ) and carboxylate (—CO 2   − ) groups. 
     
     
         9 . The photovoltaic device of  claim 1 , wherein the fullerene group is selected from the group consisting of a mono-fulleropyrrolidium group and a bis-fulleropyrrolidium group. 
     
     
         10 . The photovoltaic device of  claim 1 , wherein the compound has the structure: 
       
         
           
           
               
               
           
         
         wherein F is a fullerene group; 
         B is a N-containing ring having from 5-7 ring atoms; 
         R 1  and R 2  are independently selected from the group consisting of a polyalkylene oxide and a C1-C20 alkyl optionally substituted with an anionic center; 
         Ar is —C 6 H 5 -PEO, wherein —C 6 H 5 -PEO is selected from the group consisting of mono-, di-, tri-, and tetra-PEO substituted phenyl; and 
         A −  is a counter ion associated with the cationic nitrogen center. 
       
     
     
         11 . The photovoltaic device of  claim 1 , wherein the compound has the structure: 
       
         
           
           
               
               
           
         
         wherein F is a fullerene group; 
         B is a N-containing ring having from 5-7 ring atoms; 
         R 1  and R 2  are independently selected from the group consisting of a polyalkylene oxide and a C1-C20 alkyl optionally substituted with an anionic center; 
         Ar is —C 6 H 5 -PEO, wherein —C 6 H 5 -PEO is selected from the group consisting of mono-, di-, tri-, and tetra-PEO substituted phenyl; and 
         A −  is a counter ion associated with the cationic nitrogen center. 
       
     
     
         12 . The photovoltaic device of  claim 1 , wherein the compound has the structure: 
       
         
           
           
               
               
           
         
       
     
     
         13 . The photovoltaic device of  claim 1 , wherein the compound has the structure: 
       
         
           
           
               
               
           
         
         wherein 
         R is independently selected from the group consisting of C1-C20 straight chain and branched alkyl; 
         PEO is an alkylene oxide group independently selected from the group consisting of polyethylene oxide having the formula —(CH 2 CH 2 O) n —, where n is from 1 to about 20 or polypropylene oxide having the formula —(CH(CH 3 )CH 2 O) n —, where n is from 1 to about 20; 
         C 6 H 5 -PEO is selected from the group consisting of mono-, di-, tri-, and tetra-PEO substituted phenyl; and 
         A −  is a counter ion selected from the group consisting of fluoride, chloride, bromide, iodide, trifluoromethyl sulfonyl (CF 3 SO 3   − ), tetrakis(imidazolyl)borate (BIm 4   − ), and tetrakis(3,5-bis(trifluoromethyl)phenyl]borate (TFPB − ). 
       
     
     
         14 . The photovoltaic device of  claim 1 , wherein the compound has the structure: 
       
         
           
           
               
               
           
         
         wherein 
         R is independently selected from the group consisting of C1-C20 straight chain and branched alkyl; 
         PEO is an alkylene oxide group independently selected from the group consisting of polyethylene oxide having the formula —(CH 2 CH 2 O) n —, where n is from 1 to about 20 or polypropylene oxide having the formula —(CH(CH 3 )CH 2 O) n —, where n is from 1 to about 20; 
         C 6 H 5 -PEO is selected from the group consisting of mono-, di-, tri-, and tetra-PEO substituted phenyl; and 
         A −  is a counter ion selected from the group consisting of fluoride, chloride, bromide, iodide, trifluoromethyl sulfonyl (CF 3 SO 3   − ), tetrakis(imidazolyl)borate (BIm 4   − ), and tetrakis(3,5-bis(trifluoromethyl)phenyl]borate (TFPB − ). 
       
     
     
         15 . The photovoltaic device of  claim 1  further comprising a charge transport layer intermediate the first electrode and the active layer. 
     
     
         16 . The photovoltaic device of  claim 1 , wherein the active layer comprises an active fullerene material.