Highly Emissive Green ZnSeTe Quantum Dots: Effects of Core Size on Their Optical Properties and Comparison with InP Counterparts

InP quantum dots (QDs) are the representative environmentally benign green and red emitters in color-by-blue display devices. However, particularly green InP QDs possess inferior blue absorption capability due to their intrinsically small core size. In this work, different-sized green-emissive ZnSeTe cores are synthesized while maintaining the same Se/Te ratio. Size-dependent molar absorption coefficients (ε450 nm) at 450 nm of a series of ZnSeTe cores are assessed, nearly scaling with the core volume, and further compared with that of a green InP counterpart. Subsequently, ZnSe/ZnSeS/ZnS triple shelling is implemented on different-sized ZnSeTe cores, yielding 509–530 nm in photoluminescence (PL) wavelength, 80–92% in PL quantum yield, and a similar volume scaling of ε450 nm. For a practical verification of color-by-blue performances, InP and ZnSeTe core/shell QDs in the form of a QD plate are combined with a blue LED, revealing that the latter QDs afford more efficient blue light absorption and color conversion than the former ones.