Influence of europium nanostructure size on the emission of KBr:Eu^{2 + }

The shape and size of nanostructures formed by the precipitation of europium ions in KBr single crystal has been analyzed using optical absorption (OA), luminescence (LM) and atomic force microscopy (AFM). This work reports a relationship between the emission band peak (EBP) and the nanostructure size. The shift of the t2g absorption band towards longer wavelengths and a larger 10 Dq value reveals the growth of the nanostructures (NS). The AFM images show that the precipitates have circular shape and ∼ 20 to 400 nm diameter according to the position of EBP at around 428–433 nm. The AFM technique allowed us to relate the shape and size of the nanostructures with our previous research by OA and LM. To our knowledge, the topography of europium ions forming NS of different diameter is observed for first time.