Preparation mechanism and luminescence of Sr<sub>2</sub>SiO<sub>4</sub>: Eu phosphor from (Sr, Eu)CO<sub>3</sub>@SiO<sub>2</sub> core-shell precursor

Abstract

Sr<sub>2</sub>SiO<sub>4</sub>: Eu phosphor for white light emitting diodes (LEDs) was synthesized by employing an as-prepared (Sr, Eu)CO<sub>3</sub>@SiO<sub>2</sub> core-shell precursor as starting materials, and the effect of the core-shell precursor was also discussed on the crystal structure, particle morphology and luminescent properties of the resultant phosphor. The results showed that the hybrid β- and α′-Sr<sub>2</sub>SiO<sub>4</sub>: Eu phosphor with fine particle size and narrow distribution could be obtained at a lower firing temperature than that in conventional solidstate reaction method, and its formation mechanism was deduced to be (Sr, Eu)CO<sub>3</sub> diffusion controlled reaction process. Responded to its hybrid crystal structure, this phosphor exhibited the combined luminescence of β- and α′-Sr<sub>2</sub>SiO<sub>4</sub>: Eu

Sustainable binary/ternary blended mortars with recycled water treatment sludge using fly ash or blast slag: Characterization and environmental-economical impacts

“…When compounds such as SiO 2 , which initially have double bonds, form Si-O sigma bonds in silicate form in the concrete lattice, the peaks in the infrared (IR) spectrum shift to a lower area, that is, the wave number. For example, while sharp peaks are observed in SiO 2 at 1093, 796, and 471 cm −1 in response to stretching vibrations, in the silicate form [SiO 4 ] 4− , overlapping peaks are observed as broader bands between 1000-800 cm −1 and 600-500 cm −1 (Hu et al 2012). The FTIR spectrums of the mortars blended by waste products were examined as can be seen in Fig.…”

Sustainable cement-based materials blended with recycled water treatment sludge and other various waste products as binder: Characterization and environmental-economical impacts

“…The addition of 20% and 30% MWTS as binary and ternary blend decreased the strength and density values by generating pores in the structures as proven in the SEM images at section 3.5. sigma bonds in silicate form in the concrete lattice, the peaks in the infrared (IR) spectrum shift to a lower area, that is, the wave number. For example, while sharp peaks are observed in SiO2 at 1093, 796 and 471 cm -1 in response to stretching vibrations, in the silicate form [SiO4] 4-, overlapping peaks are observed as broader bands between 1000-800 cm -1 and 600-500 cm -1 (Hu et al 2012).…”