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Optimized ablation condition to prepare polyperinaphthalene thin films using the third harmonic wavelength of Nd:YAG laser

Ablation of mixture targets of perylenetetracarboxylic dianhydride (PTCDA) with cobalt powder is carried out using the third harmonic of a Nd:YAG laser to obtain thin films consisting of variety size of nanoparticles. FT-IR and Raman spectroscopic studies allow us to conclude that fragments without the anhydride groups of PTCDA and with better defined perylene skeleton are deposited on the substrates. Gradual increase of the electric conductivity with increasing substrate temperature during deposition suggests effective polymerization of the deposit to form polyperinaphthalene (PPN), one of low dimensional graphite family. Furthermore a Raman spectrum for each nanoparticle prepared by laser ablation at a fluence of 0.5 Jcm-2pulse-1 is successfully measured by the surface enhanced Raman spectroscopy (SERS) with a silicon tip for atomic force microscopy (AFM) coated with gold.