We investigate structure and photo-excitation in C-60-zinc tetraphenylporphyrin (ZnTPP) and C60F48-ZnTPP complexes, which are promising candidates for organic photovoltaic devices. The C-60-ZnTPP complex results from pi-pi stacking between the fullerene and porphyrin structures, and has a binding energy of 76.0 kJ/mol. Fluorination of the C-60 cage leads to decrease in ZnTPP binding, due to reduced pi-pi stacking interaction. C-60-ZnTPP photo-excitation results largely from internal ZnTPP pi-pi* transitions, although delocalised ZnTPP pi -> C-60 pi* transitions are also observed below 300 nm. The more intense photo-excitations of C-60 F-48-ZnTPP arise solely from localised ZnTPP pi > pi* transitions. (C) 2014 Elsevier B.V. All rights reserved.