Ordered blue luminescent ultrathin films by the effective coassembly of tris(8-hydroxyquinolate-5-sulfonate)aluminum and polyanions with layered double hydroxides.

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) (AQS3–) with three kinds of polyanions—poly(acrylic acid), ((C3H4O2)n, PAA), poly(styrene 4-sulfonate) ([CH2CH(C6H4)SO3]m, PSS), and poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylene vinylene] (C12H13O5S)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–...