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

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 3+ -doped CsPb(Cl 1- x Br x ) 3 PNCs with extraordinary high NIR photoluminescence quantum yields over 170%. The fabricated NIR LEDs possess an irradiance of 584.7 μW cm -2 , 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 3+ has been revealed as the main mechanism of electroluminescence (EL)-activated Yb 3+ for the first time via exploring how the trend between the EL intensity of PNC and Yb 3+ 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.