Reduced Graphene Oxide and Porphyrin. An Interactive Affair in 2-D

Photoexcited cationic 5,10,15,20-tetrakis(1 methyl-4-pyridinio)porphyn tetra(p-toluenesulfonate)(TMPyP) undergoes charge-transfer interation with chemically reduced graphene oxide (RGD) Formation of the ground-state TMPyP-RGD complex in solution is marked by the red shift of the porphyrin absorption band. This complexation was analyzed by Benesi-Hildebrand plot Porphyring flurescence lifetime reduced from 5 to 1 ns upon complexation with RGO, indicating excited state interaction between singlet excited porphyrin and RGO Femtosecond translent absorption measirements carried out with RMPyP adsorbeed on RGO film revealed fast decay of the singlet excited state, followed by the formation of a longer-living product with an absorption maximum around 525 nm indicating the formation of a porphyring radical cation. The ability of TMPyP-RGO to underfo photoinduced charge seperation was further confirmed from the photoelectrochemical measurements TMPYP-RGO coated conducting glass electrodes are capable of generating photocurrent under visible excitation These results are indicative of the electron transfer between photoexcited porphyrin and RGO. The role of graphene in accepting and shuttling electrons in light harvesting assemblies is discussed.