Polymer/silicon QDs: non-toxic, transparent and tuneable

September 07, 2016 // By Julien Happich
Looking for non-toxic alternatives to colloidal Quantum Dots (QDs) which typically consist of II−VI semiconductors that contain heavy metals such as cadmium, an international team of researchers from Sweden, Canada and China has developed a novel method to manufacture stable, biocompatible QDs in a bulk transparent polymer matrix.

Following two distinct preparation methods, the researchers obtained a hybrid composite of silicon nanocrystals (SiNCs) dispersed and encapsulated into poly-methylmethacrylate (PMMA), combining the good SiNC optical response and solid bulk of the PMMA. The transparent and stable bulk nanocomposites exhibited absolute quantum yields ranging from 30 to 40%.

What's more, the researchers demonstrated that the bulk emission of these solid blocks (under illumination of a 365nm UV lamp) could be easily tuned through one of the preparation steps, by carefully controlling the final size of the SiNCs encapsulated within the solid PMMA matrix. Blue, yellow, orange and red samples are featured in a paper "Photostable Polymer/Si Nanocrystal Bulk Hybrids with Tunable Photoluminescence" they recently published in the ACS Photonics journal.