Highly efficient narrowed emitting AgInxGa1−xS2/AgGaS2 quantum dots via an HF-assisted one-pot synthesis strategy and their light-emitting diodes

Abstract

I–III–VI semiconductor quantum dot light-emitting diodes (QLEDs) have emerged as promising lighting and display devices, celebrated for their eco-friendly nature and high-performance characteristics. Nevertheless, the conventional preparation of narrowband-emitting I–III–VI colloidal quantum dots (QDs) often involves intricate and multi-step purification processes. Herein, we present a straightforward strategy for synthesizing highly luminescent AgInxGa_1−xS₂/AgGaS₂ (AIGS/AGS) core/shell QDs through a hydrofluoric acid (HF)-assisted one-pot synthesis. The resulting AIGS/AGS QDs exhibit pure green emission at 532 nm with a narrow full width at half maximum (FWHM) of 33 nm. Notably, HF treatment plays a pivotal role in removing the adsorption layer, composed of indium sulfide and low-crystallinity gallium sulfide, from the surface of AIGS cores. This process facilitates uniform shell growth of AGS, resulting in notable improvements in color purity and photostability compared to QDs synthesized without HF treatment. As a proof of concept, we fabricated QLED devices by spin-coating AIGS/AGS QDs prepared using HF-assisted one-pot synthesis as the luminescent layer. These QLEDs showcase a narrow electroluminescence (EL) FWHM of 36 nm, a low turn-on voltage of 2.2 V, and an external quantum efficiency of 0.75%, setting a new benchmark for brightness at 2747 cd m⁻². The simplicity of this one-pot synthesis route, eliminating the need for intermediate purification steps, establishes a practical and scalable method for large-scale production of environmentally friendly I–III–VI QDs. The present work is anticipated to drive the widespread application of environmentally friendly I–III–VI QDs in QLED technology.