Controllable Nucleation and Growth of Blue InP Quantum Dots Enable Efficient and Bright Light-Emitting Diodes

Indium phosphide (InP) quantum dots (QDs) have emerged as eco-friendly substitutes for cadmium (Cd)-based QDs. However, their electroluminescence (EL) performance, especially for blue ones, lags significantly behind that of the state-of-the-art Cd-based counterparts. This disparity can be attributed to the abundant defect states arising from their high surface area/volume ratio and irregular size distribution caused by high-reactivity phosphorus (P) precursor. Herein, trimethylgermanium chloride is developed into the P precursor, effectively modulating the nucleation reaction rate and drastically reducing phosphorus oxide defects. Furthermore, the epitaxial growth of the ZnS layer is successfully achieved employing zinc diethyldithiocarbamate as the precursors. This approach not only facilitates superior crystallinity in QDs at lower temperatures but also effectively suppresses electron diffusion to the shell, thereby alleviating the persistent redshift and ensuring the peak position remains within the blue emissive range. Consequently, the synthesized blue InP/ZnS QDs demonstrate a PLQY of 73% at 474 nm, empowering them to exhibit exceptional EL performance with a peak external quantum efficiency of 2.38% and a record luminance of 2693 cd cm −2 .