Photosensitizing transition metal complex and its use for photovoltaic cell

Abstract

A photosensitizing transition metal complex of the formula (Ia) MLY 1 , (Ib) MLX 3 (Ic) MLY 2 X, (Id) MLY 3 X or (Ie) MLY 4 X in which M is a transition metal selected from ruthenium, osmium, iron, rhenium and technetium, preferably ruthenium or osmium. X is a co-ligand independently selected from NCS—, Cl—, Br—, I—, CN—, H 2 O; pyridine unsubstituted or substituted by at least one group selected from vinyl, primary, secondary or tertiary amine, OH and C 1-30 alkyl, preferably NSC and CN—; L is a tridentate polypyridine ligand, carrying at least one carboxylic, phosphoric acid or a chelating group and one substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, substituted or unsubstituted alkylamide group having 2 to 30 carbon atoms or substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms. A dye-sensitized electrode includes a substrate having an electrically conductive surface, an oxide semiconductor film formed on the conductive surface, and the above sensitizer of formula (Ia), (Ib), (Ic), (Id) or (Ie) as specified above; supported on the film. A solar cell includes the above electrode, a counter electrode, and an electrolyte deposited there between.

1 . A photosensitizing transition metal complex having the general formula (Ie):
   MLY 4 X   (Ie)
   in which M is a transition metal selected from Ru(II), Os(II), Fe(II), Re(I) and Tc(I);   L is a polypyridine ligand having the general formula (II),   
       
         
           
           
               
               
           
         
         wherein A 1 , A 2  and A 3  contain at least one anchoring group selected from —COOH, —COON(C 4 H 9 ) 4 , —PO(OH) 2 , —PO(OR 1 ) 2  (where R 1  is an alkyl group having 1 to 30 carbon atoms), —CO(NHOH), and at least one group selected from an alkyl group having 1 to 50 carbon atoms, an alkylamide group having 2 to 50 carbon atoms or an aralkyl group having 7 to 50 carbon atoms; and 
         X is a ligand selected from NCS—, Cl—, Br—, I—, CN—, NCO—, H 2 0 or pyridine group which may be substituted by vinyl, primary, secondary or tertiary amino, alkylthio, arylthio, hydroxyl or C 1-30  alkyl; and 
         Y 4  is a group selected from the formulae (IVb-1 to 3), (IVc-1 to 4), (IVd-1 to 8) and (IVe-1 to 2): 
       
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         where R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16  and R 17  are the same or different an alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an perfluoroalkyl group having 2 to 12 carbon atoms, an alkylamide group having 2 to 12 carbon atoms, an aminoalkyl group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, cyano group, hydroxyl group, nitro group, amino group, trifluoro group, halogen atom or hydrogen atom. 
       
     
     
         2 . A photosensitizing transition metal complex of  claim 1 , which is a complex of the formula (Ie) where M is Ru(II) or Os(II), X is NCS— or CN—, and Y 4  is a group of the formula (IVb-1), (IVb-2) or (IVb-3). 
     
     
         3 . A photosensitizing transition metal complex of  claim 1 , which is a complex of the formula (Ie) where M is Ru(II) or Os(II), L is a polypyrigine ligand of the formula (IIb) 
       
         
           
           
               
               
           
         
         where B 1  and B 2  are, the same or different, a hydrogen atom, 
         —COOH, —COON(C 4 H 9 ) 4 , —PO(OH) 2 , provided that any one of B 1  and B 2  is different from a hydrogen atom, and C is an alkyl group having 6 to 30 carbon atoms, Y 4  is a group of the formula (IVe-1) or (IVe-2), and X is NCS— or CN—. 
       
     
     
         4 . A photovoltaic cell comprising a support, a conductive layer formed on the support, and a porous semiconductor layer formed on the conductive layer, a counter electrode, and an electrolyte deposited there between wherein the porous semiconductor layer carries a photosensitizing transition metal complex as claimed in  claim 1 .