Coordinating Solvent Synthesis of InP Quantum Dots with Large Sizes and Suppressed Defects for Yellow Light‐Emitting Diodes

Abstract

AbstractNoncoordinating solvents are intensively investigated and used in quantum dot (QD) synthesis since they generally are not involved in the chemical reaction. Here, high‐quality heavy‐metal‐free indium phosphide (InP) QDs are prepared by adopting a coordinating solvent synthesis method in which the trioctylamine (TOA) used is a one of a kind L‐type ligand that can coordinate with the In precursor and compete with the P precursor simultaneously, which decreases the nucleation sites and increases their growth rates, resulting in relatively larger‐sized InP QDs compared to those obtained by the conventional noncoordinating solvent of 1‐octadecene (ODE). By further coating the shell of ZnSe/ZnS, the core/shell structured InP QDs demonstrate a yellow emission with the highest photoluminescence quantum yields (PLQY) of up to 82%. The zinc chloride treatment via in situ ligand exchange further passivates the sulfide vacancies, which not only avoids the luminescence quenching of QDs but also facilitates the hole injection from the hole transport layer (HTL) to QDs. As a result, the resulting yellow InP QDs‐based light emitting diode (QLED) achieves a maximum external quantum efficiency (EQE) of 7.76% and an operational lifetime of 290 h at an initial luminance of 100 cd m−2.