KrF excimer laser for Pt–NPs synthesis by PLAL in isopropanol solution and their use in a SERS application

Pulsed laser ablation in aqueous isopropanol (IPA) solution (PLAL) using KrF excimer laser was employed for the first time to produce platinum nanoparticles (Pt–NPs). The dependence of their optical and morphological properties on the IPA concentration and ablation time at certain values of the laser fluence (LF) and repetition rates (RR), was investigated. The UV/Vis transmission (T) spectra of the Pt–NPs were measured to assess indirectly their type, relative mean size (MS) and standard deviation (SD). Peculiarities of this spectra, related to the presence of a volatile component in the solution are discussed. Morphological properties as shape, MS, SD, and microstructure were studied via High-Resolution Scanning Transmission Electron Microscopy (HR-STEM). The created Pt–NPs show spherical shape with smallest MS value of 1.7 nm using 2.3 Jcm−2 LF, 10 Hz RR and 10 min ablation time in 80% aqueous IPA solution and the narrowest SD of ±0.7 nm with the same technological parameters but using 30% IPA concentration. The Pt nature of the NPs was confirmed by Energy Dispersive X-Ray technique. The crystallographic structure was determined by HR-STEM and X-ray diffraction measurements. An application of the synthesized Pt–NPs is presented using their role as substrate in methylene blue through surface-enhanced Raman spectroscopy method.