Endowing quantum dots (QDs) with robustness and durability has been one of the most important issues in this field, since the major limitations of QDs in practical applications are their thermal and oxidative instabilities.In this work, we propose a facile and effective passivation method to enhance the photochemical stability of QDs using polymeric double shell structures from thiol-terminated poly(methyl methacrylate-b-glycidyl methacrylate) (P(MMA-b-GMA)-SH) block copolymer ligands. To generate densely cross-linked network, the cross-linking reaction of GMA epoxides in PGMA block was conducted using Lewis acid catalyst under an ambient environment in order not to affect the photophysical properties of pristine QDs. This provides QDs encapsulated with robust double layers consisting of highly transparent PMMA outer-brush and oxidation-protective crosslinked inner-shell. Consequently, the resulting QDs exhibited exceptional tolerance to heat and oxidants when dispersed in organic solvents or QD-nanocomposite films, as evidently corroborated under various harsh conditions with respect to temperature and oxidant species. The present approach not only provides simple yet effective chemical means to enhance the thermochemical stability of QDs, but also offers a promising platform for the hybridization of QDs with polymeric materials for developing robust light-emitting or light-harvesting devices.
Originally published at chemistry.nd.edu.