Blue-Emitting ZnSeTe/ZnSe/ZnS Quantum Dots for Efficient Electroluminescent Application

Abstract

ZnSeTe quantum dots (QDs), as a promising environmentally friendly emitter, have been extensively studied for blue quantum dot light-emitting diodes (QLEDs). Although numerous reports have focused on QD shell structures and surface treatments, very few reports have investigated ligand reaction byproducts, which also play an important role in QD surface decoration. Herein, we propose a strategy of chloroform post-treatment to improve QD optoelectronic properties. In detail, the Cl– byproduct produced through the reaction between chloroform and the tri-n-octylphosphine (TOP) ligand effectively passivates QD surface defects for enhanced radiative recombination and further removes the native oleic acid ligand for efficient charge transportation. Consequently, the photoluminescence quantum yield (PLQY) substantially improved from 39.6 to 92.0%, and the average QD lifetime increased from 37.1 to 65.2 ns, which promoted an over 3-fold improvement in the device efficiency from 0.62 to 2.25%. This work provides an effective method to tailor QD surface states for improved electroluminescence.