Color-Tunable Highly Bright Photoluminescence of Cadmium-Free Cu-Doped Zn-ln-S Nanocrystals and Electroluminescence

摘要

A series of Cu doped Zn-In-S quantum dots (Cu:Zn—In—S d-dots) were synthesized via a one-pot noninjection synthetic approach by heating up a mixture of corresponding metal acetate salts and sulfur powder together with dodecanethiol in oleylamine media. After overcoating the ZnS shell around the Cu:Zn—In—S d-dot cores directly in the crude reaction solution, the resulting Cu:Zn-In~S/ZnS d- dots show composition-tunable photoluminescence (PL) emission over the entire visible spectral window and extending to the near-infrared spectral window (from 450 to 810 nm), with the highest PL quantum yield (QY) up to 85%. Importantly, the initial high PL QY of the obtained Cu:Zn— In~S/ZnS d-dots in organic media can be preserved when transferred into aqueous media via Hgand exchange. Furthermore, electroluminescent devices with good performance (with a maximum luminance of 220 cd m~(-2), low turn-on voltages of 3-6 V) have been fabricated with the use of these Cd-free low toxicity yellow-emission Cu:Zn~In—S/ZnS d-dots as an active layer in these QD-based light-emitting diodes.