Thick inorganic shells endow colloidal nanocrystals (NCs) with enhanced photochemical stability and suppression of photoluminescence intermittency (also known as blinking). However, the progress of using thick-shell heterostructure NCs in applications has been limited due to the low photoluminescence quantum yield (PL QY ≤ 60%) at room temperature. Here, we demonstrate thick-shell NCs with CdS/CdSe/CdS seed/spherical quantum well/shell (SQW) geometry that exhibit near-unity PL QY at room temperature and suppression of blinking. In SQW NCs, the lattice mismatch is diminished between the emissive CdSe layer and the surrounding CdS layers as a result of coherent strain, which suppresses the formation of misfit defects and consequently permits ∼100% PL QY for SQW NCs with a thick CdS shell (≥5 nm). High PL QY of thick-shell SQW NCs is preserved even in concentrated dispersion and in film under thermal stress, which makes them promising candidates for applications in solid-state lightings and luminescent solar concentrators.
Bibliographical noteFunding Information:
This research was financially supported by Korea Institute of Science and Technology (KIST, 2E26530), the Ministry of Trade, Industry & Energy (MOTIE, 10051541) and Korea Display Research Consortium (KDRC) support program for the development of future devices technology for display industry
© 2016 American Chemical Society.
- coherently strained heterostructure
- critical thickness
- misfit defect
- near-unity photoluminescence quantum yield
- spherical quantum well
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy(all)