Molecular design confirmation for proposition of improved photophysical properties in a dye-intercalated layered double hydroxides

Abstract

In the present research, Zn₂Al layered-double hydroxide (LDH) intercalated with Acid Red 27 was prepared by coprecipitation method, while solutions of Zn(II) and Al(III) nitrate salts reacted with an alkaline solution of Acid Red 27. Successful intercalation of the Acid Red 27 molecules into the interlayer space of LDH was confirmed by powder X-ray diffraction, FTIR spectroscopy, and thermal gravimetric analysis (TGA). The photoluminescence (PL) analysis and diffuse reflectance spectroscopy (DRS) were investigated and correlated with fluorescent property and photocatalytic capability of the Red 27–Zn₂Al-LDHs system. The interlayer structure, nonbonding forces, and H-type (face-to-face arrangement) aggregates of the Acid Red 27 molecules in the interlayer space of the Zn₂Al-LDH layers were studied by molecular dynamic simulation. Geometry optimization, radial distribution function (RDF), mean square displacement (MSD), and angle distribution of the Acid Red 27 molecules were calculated using the trajectory files on the basis of molecular dynamic (MD) simulations. Good agreement between the calculated and measured X-ray diffraction patterns was obtained. The MD results indicated that the Acid Red 27 molecules were more immobilized when aggregated with coplanar conformation and intercalated into the LDH layers. The aggregation-induced emission improvement of the Red 27–Zn₂Al-LDHs system was studied for predicating the effective photofunctional properties of Red 27–Zn₂Al-LDHs.