Stable Dispersions of Aromatic Hydrocarbon Colloidal Particles by Laser Ablation

Abstract

Dispersions of colloidal particles of polycyclic aromatic hydrocarbons were obtained by nanosecond laser ablation. Aqueous suspensions of micron-sized crystals were irradiated with the second harmonic output of a Nd:YAG laser and converted into colloidal particles. Ionic and nonionic surfactants were used in the ablation process to stabilise the particles. Dispersions with good long term stability were obtained. A strong dependence of particle formation rate on laser fluence was found and the particle formation process is discussed on the basis of UV-Vis spectra and microscopic examination of the crystals.

Direct Condensation Method for the Preparation of Organic‐Nanoparticle Dispersions

“…The laser-ablation method was investigated in detail for the preparation of different phthalocyanine nanoparticles, [15] and the preparation of tetracene and pentacene nanoparticles was recently reported. [16,17] Using laser ablation, more concentrated nanoparticle dispersions can be prepared compared to the repreciptation method. But as particle formation only occurs within the narrow laser beam, only small amounts of these nanoparticle dispersions can be prepared.…”

Synthesis of Zirconium Nanoparticles by Ultrafast Laser Ablation

“…Characteristics of nanoparticles produced by laser ablation have been shown to be affected by wavelength [23,24], and control over properties can be attained by utilizing the visible absorption of plasmon resonance bands [25][26][27]. The liquid environment also plays a factor in nanoparticle synthesis as shown by studies made with various liquids and surfactants, whereupon the resultant nanoparticles have been characterized [15,16,[28][29][30][31]. Laser ablation processes involve extremely high energies which are central to the synthetic method, where material is superheated and ejected into the liquid medium.…”