title: Ordered blue luminescent ultrathin films by the effective coassembly of tris(8-hydroxyquinolate-5-sulfonate)aluminum and polyanions with layered double hydroxides.
abstract: This article reports a novel method to assemble a small anion with exfoliated Mg-Al-layered double hydroxide (LDH) nanosheets into ordered ultrathin films (UTFs) by employing the layer-by-layer assembly technique. The premixing solution of tris(8-hydroxyquinolate-5-sulfonate)aluminum(III) (AQS(3-)) with three kinds of polyanions-poly(acrylic acid), ((C(3)H(4)O(2))(n), PAA), poly(styrene 4-sulfonate) ([CH(2)CH(C(6)H(4))SO(3)](m), PSS), and poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylene vinylene] (C(12)H(13)O(5)S)(n), PPV)-has been used as building blocks to assemble alternatively with LDH nanosheets. The UV-vis absorption and fluorescence spectroscopy of (AQS-polyanion/LDH)(n) UTFs presents stepwise growth upon increasing deposited cycles in comparison with the (AQS/LDH)(n) film under the same experimental process. (AQS-PPV/LDH)(n) UTF displays complex fluorescence originating from AQS and PPV. The (AQS/LDH)(n) and (AQS-polyanion/LDH)(n) UTFs exhibit higher blue-polarized photoemission character with a luminescence anisotropy (r) of ca. 0.12-0.20 and a longer fluorescence lifetime than that of the Na(3)AQS film with r = 0.04. X-ray diffraction, scanning electron microscopy, and atomic force microscopy demonstrated that the UTFs were orderly periodically layered structures with a thickness of ca. 3.0 nm per bilayer. Therefore, this work gives a feasible method for immobilizing small anions into the gallery of LDHs.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Shuangde
authors.initials: S
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Hongkai
authors.initials: H
authors.lastname: Ma
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.forename: Dongpeng
authors.initials: D
authors.lastname: Yan
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: David G
authors.initials: DG
authors.lastname: Evans
authors.forename: Xue
authors.initials: X
authors.lastname: Duan