Abstract
We present a one-pot synthetic method to prepare alloyed [Cd1-xZnxSe1-ySy] quantum dots with controllable bimodal size distribution and high quantum efficiency for the first time. In a typical synthesis of bimodal alloyed quantum dots, alloyed [Cd1-xZnxSe] seeds consisting of two size distribution are prepared in the initial stage, followed by incorporation of sulfur precursor which promotes further growth and shelling processes. Finally, the bimodal alloyed [Cd1-xZnxSe1-ySy] quantum dots (QDs) with high quantum yield are obtained. The bimodal wavelength and relative photoluminescence intensity of bimodal QDs are controlled by experimental factors based on the thermodynamics and kinetics. We present that existence of chemical potential well for nanoparticles is a critical parameter to control the characteristics of the bimodal alloyed QDs. Finally, we demonstrate the potential of the as-prepared bimodal alloyed QDs in the application of white light emitting diodes (WLEDs) through coupling them with the blue-light InGaN chips. The color axis, color rendering index, and color gamut of the WLEDs are simply modified via changing the synthetic parameters without any post-mixing procedure. Hence, the fabricating process has been dramatically simplified, and the possible contamination from the purification process and environment may be reduced. The one-pot bimodal alloyed QDs based WLEDs definitely is a promising candidate in the lighting and display applications.