Controlled growth of zinc oxide crystals with tunable shape

Micro-sized ZnO crystals with different shapes have been successfully synthesized by a simple solvothermal reaction of zinc nitrate hexahydrate and julolidine in N, N-dimethylformamide (DMF). The growth of ZnO crystals with tunable shape was controlled through a suppressed crystal growth of the (0 0 0 1) facets along c-axis direction due to the julolidine compound selective adsorbing on the positive (0 0 0 1) facets by coordinating Zn cations with its N atoms. Systematic reactions in the presence of different amounts of DMF were conducted to control the formation of various well-shaped ZnO crystals. The selective adsorption of julolidine on the growing facets resulted in the formation of grooved hexagonal disks, hexagonal disks, hexagonal pyramids, and hexagonal rods.