Drop-on-demand inkjet printing of highly luminescent CdS and CdSe@ZnS nanocrystal based nanocomposites

Inkjet printing technology is an emerging deposition method for the flexible and cost-effective dispensing of functional materials. In this work, luminescent single- and multi-colour pixel arrays of chloroform nanocomposite inks based on polystyrene (PS) functionalized with highly luminescent colloidal CdS and differently sized CdSe@ZnS nanocrystals (NCs) were printed in drop-on-demand mode. The solubility of the organic-capped NCs in organic solvents allowed the employment of chloroform for preparing highly processable luminescent nanocomposite inks. We demonstrated that nanocomposite inks in a single apolar carrier medium, can be reliably dispensed once optimized the ejection parameters, with no need of multi-solvent mixtures or post preparative processing. The bright and non-bleachable sizedependent luminescence of the NCs is conveyed to the printed pixels which present a luminescence ranging from blue to red and a regular and reproducible shape.