Linear and nonlinear spectroscopic studies of phthalocyanine-carbon nanotube blends

Stable phthalocyanine-single-walled carbon nanotube (SWNT) composite solutions were prepared by blending metallophthalocyanine solutions and SWNT dispersions. The addition of SWNTs does not affect the linear absorption bands, but results in a significant fluorescence quenching of phthalocyanine molecules. The nonlinear optical properties of these nanocomposite systems were characterized by means of the Z-scan technique with nanosecond pulses at 532 nm. The nanotube dispersions in N,N-dimethylformamide can improve the nonlinear extinction of the whole system more effectively than the N-methyl-2-pyrrolidone dispersions. In comparison to pure phthalocyanine solutions, the phthalocyanine-SWNT composites can enhance the nonlinear extinction effect at higher incident intensities.