Assembly of individual TiO2-C-60/porphyrin hybrid nanoparticles for enhancement of photoconversion efficiency

Abstract

Rational organization of porphyrin and C-60 on the electrode surface in photovoltaic structures is essential to yield high quantum efficiency. In the present work, individual TiO2 nanoparticles were modified by introducing C-60 and porphyrin units on the surface, and then electrophoretically deposited on an ITO/SnO2 electrode. The morphology of the photoactive layer on the electrode was significantly different from that of the layer produced as a result of separate deposition of C-60 and porphyrin. The maximum incident photon to current efficiency of the resulting electrode approached 88% at 410 nm, which is the highest value among molecule-based photovoltaic cells reported to date. This indicates that molecular assembly of the C-60 and porphyrin units on the individual nanoparticles through strong chemical attachment is a key factor in improving effective electron transfer between the photoactive units and the electrodes.