The Solvent Effects on the Formation of Polyynes by Laser Ablation

Abstract

(≥ 99.0%), n-octane (≥ 99.0%). These solvents were purchased from Sigma-Aldrich and used without further purification. The surface of the graphite target was polished with 1200grade emery paper prior to laser irradiation using a Qswitched Nd:YAG laser (Continuum, Surelite I, λ = 1064 nm, pulse duration 5 ns) operated at 10 Hz. The energy of the laser was maintained at 20 mJ/pulse in order to avoid generation of splashes. The laser beam was loosely focused using a lens with a focal length of 300 mm and the typical irradiation time was 20 min. The solution was stirred during the ablation using a magnetic stirrer. The target was also continuously rotated to minimize the effect of target aging and to provide some stirring effect. The optical properties of the nascent polyynes solutions were studied at room temperature in various solvents by a UV-vis absorption spectrophotometer (Shimadzu UV1800) and normal Raman spectra were recorded by a spectrophotometer (HORIBA T64000).