Growth and Brilliant Photo-Emission of Crystalline Hexagonal Column of Alq(3) Microwires

We report the growth and nanoscale luminescence characteristics of 8-hydroxyquinolinato aluminum (Alq(3)) with a crystalline hexagonal column morphology. Pristine Alq(3) nanoparticles (NPs) were prepared using a conventional reprecipitation method. Crystal hexagonal columns of Alq(3) were grown by using a surfactant-assisted self-assembly technique as an adjunct to the aforementioned reprecipitation method. The formation and structural properties of the crystalline and non-crystalline Alq(3) NPs were analyzed with scanning electron microscopy and X-ray diffraction. The nanoscale photoluminescence (PL) characteristics and the luminescence color of the Alq(3) single NPs and their crystal microwires (MWs) were evaluated from color charge-coupled device images acquired using a high-resolution laser confocal microscope. In comparison with the Alq(3) NPs, the crystalline MWs exhibited a very bright and sharp emission. This enhanced and sharp emission from the crystalline Alq(3) single MWs originated from effective π-π stacking of the Alq(3) molecules due to strong interactions in the crystalline structure.