Charge separation dynamics at molecular heterojunction of C60 and zinc phthalocyanine

A molecular heterojunction of C-60 and zinc phthalocyanine (ZnPc) is one of the prospective candidates for creating organic thin film solar cells. Carrying out Ehrenfest dynamics simulations on the basis of the time-dependent density functional theory, we investigate how the charge separation proceeds between C-60 and ZnPc at different intermolecular distances when C-60 is put on top of ZnPc. We find that the charge separation becomes most efficient around d=3.0 A degrees. In addition, if oligo (p-phenylenevynilene) periphery is attached to the ZnPc core, the concurrence of the light-harvesting property of this nearly planer pi conjugated complex makes the photoabsorption range wider.