Non-cadmium" dual emissive QDs have been directly synthesized using a one-pot hot-injection technique. A white LED was successfully fabricated using a commercial blue-LED chip combined with the optimal QDs.
ABSTRACTThe global demand for resource sustainability is growing. Thus, the development of single-source environment-friendly colloidal semiconductor nanocrystal (NC) phosphors with broadband emission is highly desirable for use as color converters in white light-emitting diodes (WLEDs). We report herein the gram-scale synthesis of single-source, cadmium-free, dual-emissive Mn-doped Zn-Cu-In-S NCs (d-dots) by a simple, non-injection, and low-cost approach in one-pot fashion. This synthesis approach led to the formation of NCs with continuously varying compositions in a radial direction because the reactivity of precursors totally differed among these precursors. Consequently, d-dots exhibited two emission bands, one of which was due to Mn-related emissions and the other was due to the band edge of Zn-Cu-In-S NCs. Emission peaks assigned to band edge were tunable by simple control of particle size and composition. The prepared d-dots also exhibited the characteristic zero self-absorption, a quantum yield of 46%, and good thermal stability. A combination of a commercial blue LED chip with optimal d-dots as color converters gave a high color rending index of up to 90, Commission International de l'Eclairage color coordinates of (0.332, 0.321), and correlated color temperature of 5680 K. These results suggested that this cadmium-free, excellent thermally stable single-phase d-dot phosphor had potential applications in WLEDs.
Nano Research
DOI () Research Article| www.editorialmanager.com/nare/default.asp 2 Nano Res.