Green InP Quantum Dots with High Brightness and Narrow Emission through Layer-by-Layer Modification with Aluminum

InP quantum dots (QDs) show a unique promise for display and lighting applications. However, the synthesis of InP QDs with high optical quality is much more difficult compared to that of Cd-based QDs and Pb-based perovskites. Here, we established a layer-by-layer modification approach to improve the optical properties of the InP QDs. InP QDs with green emission were prepared using tris(dimethylamino)phosphine ((DMA)₃P). By introducing aluminum isopropoxide (AIP) twice during the formation of the ZnSeS and ZnS shell layers, we increased the photoluminescence quantum yield (PLQY) of the resulting Al-modified InP/ZnSeS/ZnS QDs to 96%. The full-width-at-half-maximum (fwhm) could be narrowed to 37 nm. It was speculated that the introduction of Al could alleviate the charge mismatch between the cores and shells and passivate surface defects. In addition, AIP might form oxides on the outer layers of QDs, thus enhancing their stability. Moreover, the green light-emitting diode (LED) based on Al-modified InP/ZnSeS/ZnS QDs performed well with a maximum power efficiency of 28 lm/W. This work finds a way to obtain InP QDs of high brightness and narrow emission by modification in the midsynthetic process, which will inspire the synthesis of better InP QDs.