Carboxylic-Free Synthesis of InP Quantum Dots for Highly Efficient and Bright Electroluminescent Device

摘要

In the synthesis of InP-based quantum dots (QDs), the environmentallyfriendly carboxylic-free phosphor precursor tris(dimethylamino)phosphine((DMA)_3P) has been frequently used to replace tris (trimethylsilyl)phosphine(TMS)3P, in order to prevent the InP cores from oxidation and avoid the dangerousetching with hydrofluoric acid. However, the InP-based QDs synthesizedwith (DMA)_3P still perform poorly in quantum dot light-emitting diodes(QLEDs) due to oxidation by other carboxylic sources. In this work, basedon the synthesis with (DMA)_3P, ZnCl_2 precursor instead of zinc carboxylateis used for shell growing, and oleylamine is used as solvent instead of oleicacid, so that there is no oxidizing agent such as carboxylic groups during thewhole synthesis process. As a result, highly efficient InP/ZnSe/ZnSeS/ZnSQDs with gradient varying shells are obtained, whose full width at half-maximum(≈41 nm) and photoluminescence quantum yield (≈96) are narrowestand highest among the reported ones, respectively. The QLEDs based on InPQDs synthesized with (DMA)_3P achieve breakthrough efficiency of 12.39.Especially, high efficiency and high brightness are achieved at the same time.This work opens a new avenue in the synthesis of high-quality and environmentalfriendly InP-based QDs.