Double beam pulsed laser deposition of composite films of poly(methyl methacrylate) and rare earth fluoride upconversion phosphors

Abstract

The objective of the work is to demonstrate feasibility of producing functional polymer nanocomposite films for light emitting applications using the new double beam pulsed laser deposition (DPLD) technique. The existing pulsed laser deposition vacuum chamber has been modified to accommodate two laser beams of different wavelengths for the in situ ablation of two targets: a polymer host and a rare earth based highly efficient upconversion emitting inorganic dopant. Special provisions were made for cooling the target to control the ablation of the polymer without interrupting the process. Nanocomposite films of acrylic polymer and nanoparticles of the compounds of the rare earth elements were fabricated by the proposed method with near-infra-red laser radiation (1064-nm wavelength) ablating the polymer targets and visible radiation (532nm) ablating the inorganic targets. The fabricated nanocomposite films were characterized using atomic force microscopy, X-ray diffraction, optical fluorescence spectroscopy, and visual observation of the fluorescence. It was discovered that the produced polymer nanocomposite films retained the crystalline structure and the upconversion fluorescence properties of the initial rare earth compounds mainly due to the better control of the deposition process of the materials with substantially different properties. The proposed method can be potentially used for making a wide variety of composite films.