Abstract
Amorphous tris(8-hydroxyquinolme)alaminum (AlQ <sub>3</sub> ) nanoparticles can be grown directly into α-phase crystalline nanowires in a one-step heat treatment. At the most appropriate Ar pressure, heating time, and heating temperatures (between 150 and 190 °C), fine and long nanowires are obtained. The growth of the nanowires is dictated by the anisotropic bonding in α-AlQ <sub>3</sub> crystals. The growth mechanism is illustrated by the concept of nucleation and molecular migration. Two exotherms are revealed, from differential scanning calorimetry analyses, in the transformation process of AlQ <sub>3</sub> amorphous nanoparticles to crystalline nanowires. The first exotherm is the transition from amorphous nanoparticles to the γ-phase, and the second exotherm is the transition from the γ- to the α-phase. By means of Kissinger plots, the activation energies for the crystallization of the γ-phase and the transition from the γ- to the α-phase are calculated, for the first time, to be 9.7 and 12.1 kJ mol <sup>-1</sup> , respectively. A blue-shift and higher intensity of photoluminescence after heat treatment are also demonstrated. © 2006 WILEY-VCH Verlag GmbH &. Co. KGaA.