Luminescent metal clusters/barium sulfate composites for white light-emitting devices and anti-counterfeiting labels

The applications of luminescent metal nanoclusters (NCs) in device fabrication have been greatly limited by their tough solidifying process and poor stability. In this work, we report the facile preparation of metal NCs/barium sulfate (BaSO₄) composites by incorporating luminescent metal NCs into BaSO₄ matrix by subsequent addition of Ba²⁺ and SO₄ ^2- ions into the aqueous dispersions of the metal NCs. The resulting NCs/BaSO₄ composites maintained the luminescent colour of the metal NCs and possessed improved stability under external stimuli, such as heating, strong acid and organic solvents. The solid metal NCs/BaSO₄ composites with blue, green and red emissions were suitable for the fabrication of white light-emitting devices (WLEDs) and multicolour anti-counterfeiting labels.