Single-phase colour-tunable yellow light copper doped zinc sulfide quantum dots for fabrication of white LEDs

Abstract

To achieve large-scale commercialized use of white quantum dots light-emitting diodes (WQLEDs). It is vital to find environmentally friendly and inexpensive luminescent materials without rare earth participation. In this paper, the zinc sulfide quantum dots with different Cu2+ contents (ZnS:Cu-QDs) were prepared by one-step hydrothermal method, the quantum yield can reach 27.65 % and the thermal decomposition temperature is 610 ℃. Furthermore, the luminescence mechanism of ZnS:Cu-QDs was explored. The wavelength-tunable WQLEDs were fabricated. The WQLEDs exhibit from standard white light to warm white light with a relative colour temperature in the range of 4764–3851 K. The as-prepared WQLEDs from ZnS:Cu0.8 %-QDs show a warm white light with International Commission on Illumination (CIE) coordinates of (0.4009, 0.4265), colour rendering index (CRI) of 72.1, and the correlated colour temperature (CCT) of 3851 K at an input voltage of 3.4 V. This research provides a promising way for achieving WQLEDs by single phase quantum dots without the addition of rare-earth elements.