Matrix assisted growth of nanoparticles and nanoporous films

Abstract

Since the inception of matrix assisted pulsed laser evaporation (MAPLE), a large body of research has focused on the structure and property preservation of soft materials. Departing from this precedent, a variation of MAPLE to grow complex inorganic nanoparticles and nanoporous thin films from acetate precursors is presented. While some aspects of MAPLE are retained, a weakly absorbing matrix solvent is used to promote absorption by the precursors, leading to photothermal decomposition. The diffusion of ions within the laser interaction volume results in the formation of nanoparticles, which are then ejected by subsequent pulses. The acetate precursors were processed into colloidal suspensions in deionized water and frozen to form solid targets, followed by irradiation with a pulsed excimer laser at fluences ranging from 0.25 to 0.75 J/cm2. Nanoparticles and nanoporous films of unary, binary, and ternary metallic and oxide systems were deposited at room temperature onto substrates of Si and electron-transparent grids. Size distributions varied between different material systems with negligible pressure and energy effects, with distribution extrema ranging from 2 to 100 nm in diameter. Characterization of the nanoparticles was performed by high resolution scanning and transmission electron microscopy, and energy dispersive x-ray spectroscopy.