Fig. 4: Characterization and optimization of NIR-II LnLEDs.
From: Triplets electrically turn on insulating lanthanide-doped nanoparticles
a, Energy band diagram of LnLEDs. b, Cross-sectional HAADF STEM image of the YbLED and corresponding element mapping of different layers. Scale bars, 50 nm. c, Simulated light-extraction efficiency of the LnLED as a function of emitting wavelength in the NIR range. d–f, Current density and NIR radiance (measured with corresponding long-pass filters) versus voltage for different LnLEDs. g, NIR EQEs of the NdLED/YbLED/ErLED versus current densities. h, Normalized EL spectrum of the Yb@NdLED. i, NIR EQE enhancement by using core–shell Yb@Nd LnNPs and optimizing the device structure.
