Efficient green indium phosphide quantum dots with tris(dimethylamino)-phosphine phosphorus precursor for electroluminescent devices

In this study, green indium phosphide (InP) quantum dots (QDs) were synthesized using a tris(dimethylamino)phosphine ((DMA)3P) phosphorus source and applied to electroluminescent quantum light-emitting diodes (QLEDs). The (DMA)3P precursor is safer and more cost-effective than the conventional tris(trimethylsilyl)phosphine. The emission peak of the InP QDs was shifted to the green region from the red by replacing the conventional zinc precursor ZnCl2 with ZnI2. The surface reaction rate was limited using ZnI2 in the core formation step, yielding small-sized QDs to achieve green emission. In addition, with the optimal ZnSeS intermediate shell and outer shell, the maximum quantum yield of 67.5% with a narrow full width at half maximum of 46 nm was achieved for the (DMA)3P-based green-emitting InP@ZnSeS/ZnS QDs. QLEDs were demonstrated with the (DMA)3P-based green InP QDs, and their efficiency was maximized by optimizing the Mg doping ratios in the electron transport layer (ETL) of ZnMgO. The maximum external quantum efficiency of 1.68% and current efficiency of 4.79 cd/A were achieved with an optimal doping ratio of 12.5% ZnMgO for the (DMA)3P-based green InP QLEDs. This study demonstrates that safer (DMA)3P phosphide source-based green InP QDs are effective in achieving low-cost InP QLEDs.