Near-Infrared LEDs Based on Quantum Cutting-Activated Electroluminescence of Ytterbium Ions.

Shen, Xinyu; Wang, Zhenyu; Tang, Chengyuan; Zhang, Xiangtong; Lee, Bo Ram; Li, Xin; Li, Daguang; Zhang, Yu et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

Cesium lead halide perovskite nanocrystals (PNCs) exhibit promising prospects for application in optoelectronic devices. However, electroactivated near-infrared (NIR) PNC light-emitting diodes (LEDs) with emission peaks over 800 nm have not been achieved. Herein, we demonstrate the electroactivated NIR PNC LEDs based on Yb<sup>3+</sup>-doped CsPb(Cl<sub>1-<i>x</i></sub>Br<sub><i>x</i></sub>)<sub>3</sub> PNCs with extraordinary high NIR photoluminescence quantum yields over 170%. The fabricated NIR LEDs possess an irradiance of 584.7 μW cm<sup>-2</sup>, an EQE of 1.2%, and a turn-on voltage of 3.1 V. The ultrafast quantum cutting process from the PNC host to Yb<sup>3+</sup> has been revealed as the main mechanism of electroluminescence (EL)-activated Yb<sup>3+</sup> for the first time via exploring how the trend between the EL intensity of PNC and Yb<sup>3+</sup> varies with different voltages along with the tendency of temperature- and doping-concentration-dependent PL and EL spectra. This work will extend the application of PNCs to optical communication, night-vision devices, and biomedical imaging.