Laser wavelength-dependent size of CdSe nanoparticles synthesized by Laser Fragmentation in Liquid Medium

In this work we present a study of optical, structural and chemical properties of semiconducting CdSe nanoparticles with an organic shell prepared by laser fragmentation of acetone dispersed CdSe powder. A Nd-YAG pulsed laser of 50 Hz frequency repetition and tuned at the first and second harmonic, λ = 1064 and 532 nm, was used for the ablation. The experiment was performed during 30 min at different power intensities. The nanoparticles processing was performed at different power intensities. An important difference in the size of the nanoparticles synthesized at the infrared (IR-line, 1064 nm) and green line (G-line 532 nm) was observed, being 12 nm for the samples processed with the infrared line and 3 nm for those processed with the green line. The emission and absorption of the samples goes over from 1.8 to almost 2.4 eV for the smallest particles. A complete characterization through UV–Vis Absorption, Photoluminescence, Raman, XRD, TEM and XPS is presented and analyzed.