Synthesis, Characterization and Photoelectric Properties of the Copper Phthalocyanine-modied Multi-walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs) were grafted with sulfonyl chloride groups using chlorosulfonic acid as a sulfonation reagent, and then the amino-modified multi-walled carbon nanotubes of MWCNT-NH2 was prepared via the aminolysis reaction. The MWCNT-NH2 was further reacted with copper phthalocyanine sulfonyl chloride to prepared the complex of MWCNT-Pc. The products were fully characterized by various standard analytical techniques, including scanning electron microscope, transmission electron microscope, infrared spectroscope, UV-Vis absorption spectroscope, Raman spectroscope, X-ray photoelectron spectroscope, thermogravimetric analysis, and cyclic voltammetry. The results indicated that the complex of MWCNT-Pc was fabricated through covalent assembly of MWCNT-NH2 with copper phthalocyanine, with a copper phthalocyanine molecule for every 38 MWCNT carbons. The thermal stability of the complex of MWCNT-Pc was lower than that of MWCNT-NH2. The photoelectrode of ITO/MWCNT-Pc fabricated by the method of the spray showed a better photoelectric performance with the photovoltage and the photocurrent were 0.434V and 0.158mA/cm(2) respectively, and the internal photoconversion efficiency at 320nm was up to 19.8%. Based on the band structure of the complex of MWCNT-Pc, the photoinduced electron transfer process was proposed as follow: firstly the electronic transitions occured in the Pc moiety of MWCNT-Pc, following electrons transferred to MWCNTs and then further passed to the ITO to achieve the charge separation.