Graphene–porphyrin nanorod composites for solar light harvesting

Abstract

Well-defined organic nanostructures of porphyrin are promising candidates toward photocatalysis, photovoltaics, and electronics applications where a photoinduced electron transfer process occurs. On the other hand, reduced graphene oxides (RGO) have attracted much attention in light energy conversion owing to their efficient charge separation property. In this respect, we have demonstrated a composite of a one-dimensional (1D) nanostructure of 5, 10, 15, and 20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) and RGO for enhancing photoinduced charge separation. The composite was characterized by scanning electron microscopy (SEM), UV–visible spectroscopy, fluorescence spectroscopy, time-correlated single photon counting (TCSPC), and femtosecond fluorescence upconversion spectroscopy. It is noted that a very fast decay of TCPP NR was observed in the TCPP NR–RGO composite due to the electron transfer process, and the electron transfer rate is found to be 10.0 × 10–4 ps–1 for the TCPP NR–RGO system. An increment (1.9 fold) of photocurrent of this composite system under visible light illumination is obtained due to electron transfer from TCPP NR to RGO. This new class of porphyrin-based composite structures opens up new possibilities in solar energy conversion and photocatalytic, photovoltaic, and other new emerging applications.