Heterostructuring nanocrystal quantum dots toward intentional suppression of blinking and auger recombination

At the level of a single particle, nanocrystal quantum dots (NQDs) are observed to fluoresce intermittently or "blink." They are also characterized by an efficient nonradiative recombination process known as Auger recombination (AR). Recently, new approaches to NQD heterostructuring have been developed that directly impact both blinking and AR, resulting in dramatic suppression of these unwanted processes. The three successful hetero-NQD motifs are reviewed here: (1) interfacial alloying, (2) thick or "giant" shells, and (3) specific type-II electronic structures. These approaches, which rely on modifying or tuning internal NQD core/shell structures, are compared with alternative strategies for blinking suppression that rely, instead, on surface modifications or surface-mediated interactions. Finally, in each case, the unique synthetic approaches or challenges addressed that have driven the realization of novel and important functionality are discussed, along with the implications for development of a comprehensive "materials design" strategy for blinking and AR-suppressed heterostructured NQDs.