Fabrication of nanorods colloids of copper hexadecafluorophthalocyanine by nanosecond-pulse laser fragmentation in organic solvents

Abstract

Laser fragmentation in liquids is one of the modern techniques to prepare organic nanoparticles. Here, we reported the fabrication of copper hexadecafluorophthalocyanine (F16CuPc) nanorods in several organic solvents: methanol, ethanol, 2-propanol, and ethyl acetate. A mixture of F16CuPc microcrystals (several-μm size) and a poor solvent was exposed to nanosecond Nd3+:YAG laser pulses at the 140 mJ/cm2 for 10 min, and the sphere-like nanoparticles colloid having a mean diameter of 20–40 nm was generated. After the nanoparticle colloids stood for 1 day or a few weeks at room temperature, the morphology of the nanoparticles changed to nanorods having dimensions of 20–40 nm in width and 200–1000 nm in length, and the absorption spectra of the nanorods colloids changed from those just after laser irradiation. The absorption spectrum of the nanorods was characteristic of β-like phase F16CuPc, and high-resolution transmission electron microscope (HRTEM) observations demonstrated the single crystalline nature of the nanorods having well-aligned, one-dimensional columns of co-facial stacking of F16CuPc molecules. The prepared nanorods dispersed stably in the poor solvents for longer than several months. We examined solvent dependence of the size and the morphology of the nanorods and found that the nanorods having a large mean aspect ratio generated rapidly in a low-viscosity solvent.