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Nano Research

Article Title

Stability enhancement of PbS quantum dots by site-selective surface passivation for near-infrared LED application

Authors

Xinsu Zhang, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China
Yujuan Chen, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China
Linyuan Lian, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
Zizhen Zhang, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China
Yixuan Liu, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China
Li Song, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China
Chong Geng, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China
Jianbing Zhang, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
Shu Xu, Tianjin Key Laboratory of Electronic Materials and Devices, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin 300401, China

Keywords

PbS, quantum dot, surface modification, stability, light-emitting diode

Abstract

Infrared lead chalcogenide quantum dots (QDs) suffer fast degradation due to the easy oxidation of surface chalcogen atoms. Here, we report a trioctylphosphine-mediated surface passivation method to improve the air stability of PbS QDs. Surface mechanism study reveals an in situ surface reaction, which leads to site-selective passivation of surface S atoms with lead mono-carboxylate. The surface capping motif sufficiently protects PbS QDs from oxygen and improves their stability as well as quantum efficiency regardless of the QD size and original ligands on surface cations. The modified PbS QDs display no obvious fluorescence quenching and surface oxidization after 30 days of air exposure. The robust surface capping also provides high compatibility of PbS QDs with polymers for optoelectronic device fabrication. The near-infrared LEDs based on the modified PbS QDs display a slight degradation of only 1.47% from the maximum intensity after continuous operation in air for 250 hours (lifetime > 10,000 h) at 0.5 W/cm2 power density, indicating the surface passivation route is promising strategy for promoting practical optoelectronic application of PbS QDs

Publisher

Tsinghua University Press

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