A Double Zn and Ga Modification Strategy for Highly Efficient Deep Blue InP/ZnSeS/ZnS Quantum Dots

InP quantum dots (QDs) are regarded as the most promising star material to replace Cd-based QDs due to their excellent properties of low toxicity and tunable luminescence in the visible to infrared range. Red and green InP QDs have been shown to have excellent performance comparable to that of Cd-based QDs, but in contrast, blue InP QDs are still lagging behind. The smaller size of the core is a challenge for synthesizing high-performance blue InP QDs compared with red and green QDs. In this study, deep blue-emitting InP QDs were synthesized using a cheaper and safer phosphorus source: tris(dimethylamino)phosphine ((DMA)3P). A double Zn and Ga modification was applied to modulate the emission of InP QDs. A strategy for synthesizing deep blue luminescent In(ZnGa)P QDs was proposed, and Zn(Ac)2 was used as a precursor to react with (DMA)3P to synthesize blue InP QDs. Doping elemental Zn during nucleation inhibited the growth of the InP crystals and narrowed the lattice. Then, the Ga element further increases the material band gap by cation exchange. By introducing GaI3 into the synthesis process and utilizing the cation-exchange mechanism, deep blue emission InP QDs was realized. Tunable deep blue emission of InP QDs changed from 478 to 447 nm was achieved by this strategy. Specially, an 84% photoluminescent quantum yield is obtained for 457 nm emission QDs. This study provides clues for InP QDs to be emitted in the deep blue region, with the aim of constructing efficient deep blue QDs light-emitting diodes.