Highly Luminescent Dual-Color-Emitting Alloyed [ZnxCd1–xSeyS1–y] Quantum Dots: Investigation of Bimodal Growth and Application to Lighting

Bimodal growth and application of highly luminescent alloyed [Zn x Cd 1– x Se y S 1– y ] quantum dots (QDs) with controllable dual emission peaks in one-pot synthesis is investigated in this study. The bimodal-size-distributed alloyed [Zn x Cd 1– x Se y S 1– y ] QDs are grown from alloyed [Zn x Cd 1– x Se y ] seeds by introducing a monomer within the bimodal growth window during the seed growth. The synthesized bimodal alloyed [Zn x Cd 1– x Se y S 1– y ] QDs have a quantum yield as high as 95% under single wavelength excitation, where larger and smaller size groups individually contribute to 30% and 65%, respectively. The relative PL intensity and wavelength of the bimodal alloyed QDs can be adjusted by varying the growth time and the monomer concentrations. The dual-emitting QDs with color tunability can be directly applied to QD-converted light emitting diodes (LEDs), which need neither postmixing nor color-adjusting process to vary the color axis and the color rendering index. This one-pot synthetic approach not only solves the mixing problem of QDs from different reaction processes, but also significantly reduces the synthetic time and ignores the color-adjusting process, offering much more efficient and reliable way for lighting and display in industry.