Ligand-functionalised copper(II) hydroxide for quantum dot photoluminescence quenching

Abstract

The preparation of ligand-functionalised copper(II) hydroxide (Cu(OH)(2)) particles and their conjugation with hydrophobic CdSeS quantum dots (QDs) is reported. The photoluminescence of the QDs is efficiently quenched upon their conjugation with the functionalised Cu(OH)(2) particles. Cu(OH)(2) was functionalised with 2,2'-dipyridyl (2,2-bipy) and n-octanoic acid (OcA), by adsorption of the desired ligand to Cu(OH)(2) suspended in solvent. The resulting functionalised Cu(OH)(2) substrates were characterised using infrared, UV-visible diffuse reflectance, and X-ray photoelectron spectroscopic techniques, TEM imaging, and micro- and thermogravimetric analysis. The spectral data indicated that both 2,2-bipy and OcA coordinated to Cu(OH)(2) in a bidentate manner. The functionalised Cu(OH)(2) substrates were introduced to suspensions of hydrophobic CdSeS QDs, and the resulting QD-functionalised Cu(OH)(2) conjugates were also characterised using spectroscopic and electron microscopy techniques. UV-visible diffuse reflectance spectroscopy indicated the extension of the optical absorption of the Cu(OH)(2) to longer wavelengths upon conjugate formation.