A general polymer-based process to prepare mixed metal oxides: the case of Zn1-xMgxO nanoparticles

Nanometer-sized mixed metal oxide (MMO) particles (Zn1-xMgxO) with very precise stoichiometry are prepared employing a polymer-based method. The precursor is formed by loading a polyacrylate with metal ions followed by purification of the polymer metal ion complex via repeated precipitation/redissolution cycles. Calcination of the polymer precursor at 550 degrees C gives particles of the metastable solid solution of the ZnO/MgO system in the composition range (x<0.2 and x>or=0.82). The MMO crystal particles are typically 20-50 nm in diameter. Doping of the ZnO by Mg2+ causes a shrinkage of lattice parameter c. Effects of band gap engineering on the optical band gap are reported. The photoluminescence in the visible is also affected, and its maximum shifts from 2.12 eV (pure ZnO) to 2.32 eV at x=0.21. The crystalline MMO particles start to undergo segregation into hexagonal and cubic phases upon annealing at 800 degrees C.