Interfacial assembly of ZnO quantum dots into giant supramolecular architectures

Para-aminobenzoic acid (PABA) stabilised zinc oxide (ZnO) quantum dots (QDs) have been synthesised by refluxing zinc acetate dihydrate in methanol under alkaline condition and re-dispersed into water by centrifugation. Aqueous dispersion of PABA-stabilised ZnO QDs was taken with seven different organic solvents in test tubes and subjected to diazo reaction under specified conditions. It was seen that the quantum dots assembled into diverse superstructures depending on the nature of the immiscible solvent at the aqueous-organic interface. The assemblies so obtained have been characterised by energy dispersive X-ray (EDX) analysis, Fourier transform infrared (FTIR), fluorescence and Raman spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA), optical, fluorescence and scanning electron microscopic (SEM) images. It has been observed that the ensuing supramolecular assemblies exhibit significant electrical conductivity and photoluminescence properties.