Design of cadmium-free colloidal II-VI semiconductor quantum dots exhibiting RGB emission

The size and composition dependence of the optical gap of colloidal alloyed quantum dots (QDs) of Zn(Te1-xSex) and Zn(Te1-xSx) were calculated by the finite-depthwell effective mass approximation method. QDs that exhibited red, green and blue emission were explored to develop cadmium-free II-VI chalcogenide-based QD-phosphors. We considered that highly monodisperse colloidal QDs with diameters of 3-6 nm are easy to synthesize and II-VI semiconductor QDs usually exhibit a Stokes shift ranging between 50 and 150 meV. We showed that Zn(Te1-xSex) QDs with 0.02 <= x <= 0.68, and 0 <= x <= 0.06, and 0.66 <= x <= 0.9 may be expected to exhibit green, and blue emission, respectively. Zn(Te1-xSx) QDs with 0.26 <= x <= 0.37, 0.01 <= x <= 0.2 and 0.45 <= x <= 0.61, 0 <= x <= 0.02, and 0.63 <= x <= 0.72, should give red, green and blue emission respectively. On the basis of our calculations, we showed that Zn(Te,Se) and Zn(Te,S) QDs are very promising cadmium-free II-VI chalcogenide semiconductor QD phosphors. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).