Room-temperature solid-state synthesis and fluorescence performance of 8-hydroxyquinoline-based nanomaterial complexes with different morphology

Three main-chain 8-hydroxyquinoline-based metallocomplexes (aluminium(Ⅲ) tri-(8-hydroxyquinoline) (AlQ3), cadmium (Ⅱ) bis-(8-hydroxyquinoline) monohydrate (CdQ2·H2O), and magnesium(Ⅱ) bis-(8-hydroxyquinoline) tetrahydrate (MgQ2·4H2O)) nanomaterials were prepared by room-temperature solid-state reaction technique. The results of X-ray diffraction (XRD), elemental analyses (EA), fourier transform infrared (FTIR) spectroscopy and thermogravimetric/differential scanning calorimetry (TG/DSC) analysis demonstrated that the chemical composition of the products were AlQ3, CdQ2·H2O, and MgQ2·4H2O, respectively. The field emission scanning electron microscopy (FESEM) images and the transmission electron microscopy (TEM) images showed the morphology of AlQ3 nanoshuttles, CdQ2·H2O nanorods, and MgQ2·4H2O nanosheets, respectively. The UV–vis absorption spectra indicated that they existed charge transfer from the metal to the ligand (MLCT bands). The photoluminescence (PL) spectra revealed that three products displayed efficient and intense photoluminescence in yellow-green, deep-green and blue-green emissions region in the state of solid powder. PL intensity was weaker at different degree in chloroform, dimethylformamide, acetone and acetonitrile solutions, which attribute to solvate effect. The fluorescence quantum yields indicated that this metal complex materials can possibly act as functional composites to be used in optoelectronic devices, such as organic light-emitting diodes and fluorescent sensor.