@article{Jia2023, 
author = {Zhen Jia and Haoyun Shao and Jingyi Xu and Yu Dai and Juan Qiao},
title = {Crown ether-assisted room-temperature halide passivation for high-efficiency PbS quantum dots enabling large-area and long-lifetime near-infrared QD-OLEDs},
year = {2023},
journal = {Nano Research},
volume = {16},
number = {5},
pages = {7537-7544},
keywords = {near-infrared emission, PbS quantum dot, chloride surface passivation, crown ether, light-emitting diode},
url = {https://www.sciopen.com/article/10.1007/s12274-022-5286-2},
doi = {10.1007/s12274-022-5286-2},
abstract = {High-efficiency and low-cost near-infrared (NIR) emitting quantum dots (QDs) are highly desirable for next-generation intrinsically flexible NIR light sources. Halide passivation is commonly employed to passivate surface traps to obtain high-quality NIR-emitting PbS QDs, but this procedure requires high temperature and inert atmospheres. Here we develop a facile room-temperature halide passivation method for highly efficient NIR-emitting PbS QDs by employing crown ethers as a unique auxiliary additive. Experimental and theoretical investigations reveal that the formation of K+-crown ethers complex effectively facilitates the dissociation of KCl in toluene and releases more Cl− ions for extraordinary halide passivation at room temperature and in the air, thus improving the photoluminescence quantum yield from 24% to 35% in solution and further to 44% in blend films. The well-passivated PbS QD films are integrated with red organic light-emitting diodes (OLEDs) and the resulting QD-OLEDs exhibit high-performance NIR emission centered at 887 nm, a high external quantum efficiency of 5.2% at a radiance of 10 W·sr−1·m−2, and superior operational stability with long lifetime T90 of 188 h at the current density of 25 mA·cm−2. We also construct a large-area NIR QD-OLED (5 cm × 5 cm) with desirable uniform emission. This work opens a new avenue to achieve robust large-area NIR planar light sources for broad applications.}
}