Amine-linker length dependent electron transfer between porphyrins and covalent amino-modified single-walled carbon nanotubes

Single-walled carbon nanotube (SWNT)-porphyrin hybrid materials have received much attention due to their promising applications in photovoltaic devices, photodynamic therapy and energy conversion. Herein, three covalent amine-modified single-walled carbon nanotubes with different alkyl chain lengths have been synthesized and characterized by FT-IR, H-1 NMR, XPS, and TGA-DTA methods. The electron transfer (ET) between SWNTs and porphyrins has been studied and the important influencing ET factors, such as linker length, solvent polarity, pH and ionic strength, and central metal of porphyrin, are discussed in detail in this report. Our results indicate that shorter alkyl chain length, higher polarity of the solvent, lower pH and ionic strength are all favorable for ET, the central metal coordinated to the porphyrin macrocycle is not essential for ET.