Wavelength dependency and threshold measurements for nanoparticle-enhanced laser-induced breakdown spectroscopy

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy 2016-02, Vol.116, p.8-15
• Main Authors: EL Sherbini, Ashraf M., Parigger, Christian G.
• Format: Article
• Language: English
• Subjects: Atomic spectroscopy; Breakdown; Laser ablation; Laser induced breakdown; Laser-induced breakdown spectroscopy; Mathematical models; Nanoparticles; Nanostructure; Spectroscopy; Thresholds; Zinc; Zinc monoxide
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2015.11.006

Nanoparticles of zinc monoxide are selected for laser-induced breakdown spectroscopy with 5ns pulsed 1064nm, 532nm, and 355nm radiation from a Nd:YAG laser device. Fluences of 2 to 20J/cm2 are used, and plasma conditions are determined by recording emission spectra in the temporal window of 1 to 2μs after optical breakdown initiation. The bulk- versus nano-particle plasmas in laboratory air show that the averaged electron density and temperature values are practically identical. Enhanced signals are recorded for nanoparticles in the amount of ×10 to ×120 for 355nm radiation. The nanoparticles cause lower optical breakdown thresholds and show signal enhancements as evidenced from the analysis of the Zn I line at 481.0nm. The measured Hα line at 656.3nm usually occurs in laser-induced plasma experiments in standard ambient temperature and pressure laboratory air, and it is used in the interpretation of the bulk- and nanomaterial results. The theoretical model largely predicts and confirms the excitation wavelength-dependent experimental results. •Measurements of ZnO nano- and bulkmaterial characteristics with laser-induced plasma spectroscopy.•Comparisons of fluence thresholds for plasma initiation for nanoparticle and bulk-material.•Wavelength dependency of enhanced emissions from nanoparticles.•Presentation of a model to predict the fluence thresholds.•Nanoparticle signal enhancements of the order of ×100 at 355nm.