980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

All-inorganic perovskite (CsPbX3) nanocrystals (NCs) have recently been widely investigated as versatile solution-processable light-emitting materials. Due to its wide-bandgap nature, the all-inorganic perovskite NC Light-Emitting Diode (LED) is limited to the visible region (400-700 nm). A particularly difficult challenge lies in the practical application of perovskite NCs in the infrared-spectrum region. In this work, a 980 nm NIR all-inorganic perovskite NC LED is demonstrated, which is based on an efficient energy transfer from wide-bandgap materials (CsPbCl3 NCs) to ytterbium ions (Yb3+) as an NIR emitter doped in perovskite NCs. The optimized CsPbCl3 NC with 15 mol%Yb3+ doping concentration has the strongest 980 nm photoluminescence (PL) peak, with a PL quantum yield of 63%. An inverted perovskite NC LED is fabricated with the structure of ITO/PEDOT: PSS/poly-TPD/CsPbCl3: 15 mol%Yb3+ NCs/TPBi/LiF/AI. The LED has an External Quantum Efficiency (EQE) of 0.2%, a Full Width at Half Maximum (FWHM) of 47 nm, and a maximum luminescence of 182 cd/m(2). The introduction of Yb3+ doping in perovskite NCs makes it possible to expand its working wavelength to near-infrared band for next-generation light sources and shows potential applications for optoelectronic integration.