Gallium incorporation in blue-emitting In1−xGaxP alloy quantum dots facilitated by monomeric gallium precursors†

Abstract

Demand for environmentally friendly quantum dots (QDs) in wide color-gamut displays has led to successful development of red- and green-emitting InP QDs with outstanding optical properties. While progress in developing blue-emitting variants remains challenging, In_1−xGa_xP alloy QDs have recently garnered attention as blue emitters. However, Ga incorporation in these In_1−xGa_xP QDs is hindered by the limited reactivity of conventional gallium halide-derived precursors having a dimeric molecular structure. Here, we adopt trimethylgallium which yields monomeric gallium carboxylates as a Ga precursor in the colloidal synthesis of In_1−xGa_xP QDs. This approach promotes efficient Ga incorporation into In_1−xGa_xP QDs with narrow size distributions. The use of zinc chloride and oleylamine for ZnS shell growth on the In_1−xGa_xP cores further adjusts the photoluminescence (PL) wavelength to the blue range and enhances PL quantum yield. The resulting In_1−xGa_xP/ZnS core/shell QDs exhibit a peak emission at 470 nm, 67% of photoluminescence quantum yield, and 40 nm of emission linewidth. Successful employment of these QDs into light-emitting diodes demonstrates their potential as a blue electroluminescent emitter for future QD displays.