Light-emitting diodes based on quaternary CdZnSeS quantum dots

Highly reproducible quaternary CdZnSeS quantum dots (QDs) have been synthesized by the hot injection method using the reactivity difference between the molar ratio of Cd/Zn and Se/S precursors. The obtained QDs exhibit characteristics of quaternary CdZnSeS QDs. The morphology of the CdZnSeS QDs was observed in the TEM. The average size of the QDs was in the range between 5.5 and 7.5 nm for reaction times between 5 and 60 min, respectively. High photoluminescence emission, in the range from 460 to 680 nm, was obtained varying the Cd to Zn and the Se to S concentrations. Varying the concentration of Zn and S, emissions of blue, green, yellow, or red, were obtained. Additionally, the CdZnSeS QDs were used as the emissive layer in light-emitting diodes (LEDs) prepared with the configuration ITO/PEDOT:PSS/PVK/CdZnSeS/Al. These devices emitted a bright single color of blue, green, or red.