Controlled encapsulation of colloidal semiconductor quantum dots in a microdroplet

Abstract

Precise deposition of materials on surfaces is one of the crucial steps in a broad range of applications and functional device fabrication at both the micro- and nanoscale. Semiconductor quantum dots (QDs), with their unique optical and physical properties, have frequently been a focus of attempts for micro- or nano-positioning. Here, we present a method for reproducible, repetitive, and precise deposition of QD-containing microdroplets using hydrophobic micropipettes without any need to apply an actuation voltage. We show that upon deposition, the droplets can be translated across the surface and placed in defined patterns. The incorporation of semiconductor QDs allows for the confirmation of the morphological integrity of the microdroplets after deposition and translation. Fluorescence blinking observed for droplets containing highly diluted QD solution proves that our approach is suitable for embedding individual emitters in such microdroplets.