Full-visible spectrum emitting Zn-In-S:Cu/ZnS nanocrystals based on varying Cu concentrations and its application in white LEDs

A series of high-quality Cu-doped Zn-In-S nanocrystals (d-NCs) were prepared by a conventional hot injection process. The full-visible spectrum emission from 480 to 648 nm can be easily achieved by adjusting the Cu doping concentration in the Zn-In-S system, but not by varying the ratio of In/Zn in the alloyed host material. After wrapping the ZnS shell around the Zn-In-S:Cu d-NCs core, the resultant Zn-In-S:Cu/ZnS core/shell d-NCs not only exhibited an enhanced prominent photoluminescent quantum yield (PLQY) up to 65% but also possessed the excellent thermal, photochemical stability, and longer PL lifetime. Furthermore, high color rendition white light was generated from a single color converter Zn-In-S:Cu/ZnS core/shell NCs-assisted white light-emitting diodes (LEDs). Under operation of 38 mA forward bias current, the fabricated white LEDs emitted bright natural white light with a luminous efficiency of 62 lm/W, and the correlated color temperature of 5658 K. Simultaneously, the good color stability was accompanied by the CIE color coordinates of (0.3287, 0.3527) under different forward bias currents.