One-Pot Synthesis of InP Multishell Quantum Dots for Narrow-Bandwidth Light-Emitting Devices

With tunable emission in the full visible region, the ecofriendly InP quantum dots (QDs) show unique application prospects in light-emitting devices. At present, InP QDs suffer from wide-bandwidth emission, especially for electroluminescence (EL), which hinders their applications in high-performance display devices. Here, we report a facile one-pot synthesis of narrow-bandwidth InP/ZnSeS/ZnS QDs using a safe phosphorus source of tris(dimethylamino)phosphine, in which the ZnSeS inner-shell layer is formed via temperature-gradient solution growth from 240 to 280 °C. The synthesized green QDs have a high photoluminescence quantum yield (PLQY) of 91% and full width at half-maximum (fwhm) of 36 nm. Moreover, the resultant quantum dot light-emitting devices (QLEDs) also show a narrow fwhm of 42 nm, which is the narrowest emission of green InP QLEDs based on a safe phosphorus source reported so far. Further modulation of the electron injection into the device by inserting a thin layer of lithium fluoride results in a peak external quantum efficiency of 5.56%.