Surface modification and characterization of 8-hydroxyquinoline aluminum/nano-TiO2

8-hydroxyquinoline aluminum/nano-TiO2 composites were prepared via in situ. In order to make a better combination of the two component, Octavinyl-T8-silsesquioxane (8-vinyl POSS) was introduced into the composite system. The structure and properties of the samples were characterized by XRD, SEM, XPS, UV-visible absorption, Fluorescence spectra and Time-resolved emission-decay. These results show both β-phase and γ-phase of Alq3 exist in the composite products. Meanwhile, the addition of nano-TiO2 and 8-vinyl POSS does not change the crystalline and structure of as-prepared Alq3. Interestingly, however, XPS spectra shows that two new kinds of interaction forces emerge after the addition of 8-vinyl POSS, owing to the formation of Al-O-Si and Si-O-Ti bond, presumably. Besides, the emission intensity of Alq3/nano-TiO2 and Alq3/8-vinyl POSS/nano-TiO2 increases by 22% and 33%, respectively. The addition of TiO2 and 8-vinly POSS will not affect the position of emission peak, but will increase the transmission efficiency in electron-hole pairs. In the meantime, surprisingly, the modified Alq3 has a longer lifetime than as-prepared Alq3.