Unprecedented Alkylzinc-Magnesium Alkoxide Clusters as Suitable Organometallic Precursors for Magnesium-Containing ZnO Nanoparticles

The synthesis and characterization of the first heterobimetallic methylzinc-magnesium alkoxide clusters [Me6MgZn6(OR)(8)] [R = Et (1a), nPr (1b), nBu (1c)] with a bis-cubane-shaped MgZn6O8 core is described. The thermal degradation of 1a-c and mixtures of 1a and the homometallic MeZn-alkoxide cubane [{MeZnOtBu}(4)] (2) in dry synthetic air led to wide-band-gap semiconducting MgxZn1-xO nanoparticles at temperatures below 500 degrees C. The final materials were characterized by different analytical techniques such as PXRD, REM, TEM, EDX, and IR spectroscopy. The morphology of the as-prepared magnesium-containing ZnO samples is influenced by the different organo groups (alkoxo) in the precursors. EDX mapping showed that magnesium is uniformly distributed in the ZnO matrix. The incorporation of magnesium led to a distortion of the ZnO lattice with increased a axis and decreased c axis parameters. Room-temperature photoluminescence (PL) spectra reveal that the near-band-edge (NBE) emission of Mg2+-doped ZnO is shifted to higher energies relative to that of pure ZnO.