Fabrication, patterning and luminescence properties of X 2–Y 2SiO 5:A (A=Eu 3+, Tb 3+, Ce 3+) phosphor films via sol–gel soft lithography

Abstract

X 2–Y 2SiO 5:A (A=Eu 3+, Tb 3+, Ce 3+) phosphor films and their patterning were fabricated by a sol–gel process combined with a soft lithography. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), scanning electron microscopy (SEM) optical microscopy and photoluminescence (PL) were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 900 °C with X 1–Y 2SiO 5, which transformed completely to X 2–Y 2SiO 5 at 1250 °C. Patterned thin films with different band widths (5 μm spaced by 5 μm and 16 μm spaced by 24 μm) were obtained by a soft lithography technique (micromoulding in capillaries, MIMIC). The SEM and AFM study revealed that the nonpatterned phosphor films were uniform and crack free, and the films mainly consisted of closely packed grains with an average size of 350 nm. The doped rare earth ions (A) showed their characteristic emissions in X 2–Y 2SiO 5 phosphor films, i.e., 5D 0– 7F J ( J=0,1,2,3,4) for Eu 3+, 5D 3, 4– 7F J ( J=6,5,4,3) for Tb 3+ and 5d ( 2D)–4f ( 2F 2/5, 2/7) for Ce 3+, respectively. The optimum doping concentrations for Eu 3+, Tb 3+ were determined to be 13 and 8 mol% of Y 3+ in X 2–Y 2SiO 5 films, respectively.