Functional interlayers of fullerene derivatives and applications in organic solar cells
The invention provides novel materials, methods and designs to enable improved power conversion efficiencies of organic photovoltaics (OPVs). In particular, the invention provides novel materials and interlayers for polymer-based solar cells. Novel functional fullerene-based interlayers are disclosed that enable high efficiency devices in conjunction with numerous active layer and electrode materials.
1. A fullerene derivative having the structural formula:
wherein
R each is independently
a neutral group selected from primary, secondary, tertiary amino groups, phosphonate ester group, phosphoric acid group, or
a zwitterionic group selected from sulfobetaine, carboxybetaine, phosphobetaine and phosphorylcholine groups; and
x is an integer from 1 to 12.
2. The fullerene derivative of claim 1 , wherein the fullerene is C 60 .
3. The fullerene derivative of claim 1 , wherein the fullerene is C 70 .
4. The fullerene derivative of claim 1 , wherein all R's are identical.
5. The fullerene derivative of claim 1 , wherein all R's are not identical.
6. The fullerene derivative of claim 1 , wherein each R is a neutral group.
7. The fullerene derivative of claim 1 , wherein each R is a tertiary amino group.
8. The fullerene derivative of claim 1 , wherein each R is a zwitterionic group, wherein the zwitterionic group is selected from the group consisting of sulfobetaine, carboxybetaine, phosphobetaine and phosphorylcholine.
9. The fullerene derivative of claim 1 , wherein x is an integer from 1 to 6.