Phenethylamine ligand engineering of red InP quantum dots for improving the efficiency of quantum dot light-emitting diodes

In this Letter, red-emitting multi-shelled indium phosphide (InP) quantum dots (QDs) were synthesized using the safe phosphorus precursor tris(dimethylamino)phosphine ((DMA)₃P). The long-chain ligands of oleylamine (OAm) in the (DMA)₃P phosphide source-based InP QDs were partially exchanged with short-chain ligands of phenethylamine (PEA) in the core formation process, and the resulting InP QDs were applied to quantum dot light-emitting diodes (QLEDs). The short-chain ligands of PEA with the π-conjugated benzene ring improved the charge transport and electrical conduction of the QLEDs with (DMA)₃P phosphide source-based InP QDs. The PEA-engineering of InP QDs improved their maximum quantum yield from 71% to 85.5% with the full-width at half-maximum of 62 nm. Furthermore, the maximum external quantum efficiency of QLEDs with the PEA-engineered InP QDs improved from 1.9% to 3.5%, and their maximum power efficiency increased from 2.8 to 6.0 lm/W. This Letter demonstrates that engineering the core formation process with the short-chain ligands of PEA provides an efficient and facile way to improve the charge transport and electrical conduction in (DMA)₃P phosphide source-based InP QLEDs for electroluminescent devices.