Enhanced photoluminescence emission and surface fluorescence response of morphology controllable nano porous anodize alumina Zn-Al LDH film

We produced a large area nano film of Zn-Al layered double hydroxide (LDH), with controllable structure and top morphology, based on the top surface of nano porous anodize alumina (nano-PAA) substrate, has been prepared by the low temperature water bath method. The main factors, i.e., the reactant concentration, reactant concentration ratio, experimental temperature and time, which strongly influence the structure and morphology of nano-PAA-Zn-Al LDH film, are systematically studied and analyzed, and their effects on the unit of nano composite films, such as nano-flake (length 1–5 μm, thickness 40 nm) or nano-hydrangea-flower (diameter 1–4 μm), are investigated and summarized. Furthermore, the corresponding relationship between the photoluminescence (PL) spectra of nano-PAA-Zn-Al LDH films and the top surface morphology is experimentally studied, and the mechanism of PL enhancement is theoretically expounded. In addition, this kind of nano film has a potential application prospects in the field of Surface Enhanced Fluorescence (SEF) effect, since its SEF factor is about 6 times larger than that of the nano-PAA film and more than 60 times larger than that of a dense alumina. The great SEF factor suggests promising practical applications in single molecule detection, bio-molecular sensors and so on.