Simultaneous Double Emission of Blue-Cyan Light from Europium Nanostructures in a Solid Host

Abstract

 A sample of potassium bromide, doped with divalent europium ions, was stored at 200 °C for approximately six months and exhibited two emission bands at room temperature: blue and cyan. These emissions are associated with two types of nanostructures (NS) that form during annealing. The localized emission spectra were obtained in a scanning zone (SZ) 46 x 162 μm2 from a selected sample of 900 x 320 μm(2) and 90 μm in thickness using an experimental light-scanning design implemented in our laboratory. While scanning the crystal, several changes in the peak position and intensity of the emission spectra were observed. These changes corresponded to the stable dihalide phase (SDP) and the metastable dihalide phase (MDP). In certain regions, the intensity of the cyan emission band was slightly more significant than that of the blue emission band. The concurrent observation of these two emission bands confirms the coexistence of both phases within the single crystal.