Core-shell ZnO:Ga-SiO nanocrystals: limiting particle agglomeration and increasing luminescence surface defect passivation.

Heat treatment is needed to increase the luminescence intensity of ZnO:Ga particles, but it comes at the cost of higher particle agglomeration. Higher agglomeration results in low transparency of scintillating powder when embedded in a matrix and constitutes one of the biggest disadvantages, besides low light yield and low stopping power, of ZnO:Ga powder. Limiting ZnO:Ga particle size is therefore a key step in order to prepare highly luminescent and transparent composites with prospects for optical applications. In this work, SiO coating was successfully used to improve luminescence intensity or limitation of crystallite size growth during further annealing. Furthermore, ZnO:Ga and ZnO:Ga-SiO core-shells were embedded in a polystyrene matrix.