Effect of crystallographic phase on green and yellow emissions in Mn-doped zinc silicate nanoparticles incorporated in silica host matrix

Abstract

Silica host matrix reached by manganese-doped zinc silicate nanoparticles (SiO 2 /Zn 2 SiO 4 :Mn) were in-situ synthesized by a sol-gel process. In our approach, we synthesis ZnO:Mn nanoparticles in supercritical conditions of ethanol. After the incorporation of these nanoparticles in silica host matrix, a heat treatment at 1200°C and 1500°C for 2 h was performed for the elaboration of SiO 2 /Zn 2 SiO 4 :Mn nanocomposites. Then, these samples were characterized by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and photoluminescence (PL). These samples exhibit broad green and yellow PL bands depending on synthesis temperature. The SiO 2 /Zn 2 SiO 4 :Mn prepared at 1200°C exhibit a green emission centered at about 525 nm while the yellow emission centered at 575 nm resulted from SiO 2 /Zn 2 SiO 4 :Mn prepared at 1500°C. These two emissions are originated from internal transition in Mn 2+ ion doped zinc silicate nanoparticles and the emission wavelength is correlated to the local crystalline field which is fixed by the crystallographic phase.