Spectrally Stable and Efficient Pure Red CsPbI<sub>3</sub> Quantum Dot Light-Emitting Diodes Enabled by Sequential Ligand Post-Treatment Strategy.

Lan, Yi-Feng; Yao, Ji-Song; Yang, Jun-Nan; Song, Yong-Hui; Ru, Xue-Chen; Zhang, Qian; Feng, Li-Zhe; Chen, Tian et al. · Nano Lett · 2021

basic_science · Level V

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Abstract

Metal halide perovskites are promising semiconductors for next-generation light-emitting diodes (LEDs) due to their high luminance, excellent color purity, and handily tunable band gap. However, it remains a great challenge to develop perovskite LEDs (PeLEDs) with pure red emission at the wavelength of 630 nm. Herein, we report a spectrally stable and efficient pure red PeLED by employing sequential ligand post-treated CsPbI<sub>3</sub> quantum dots (QDs). The synthesized CsPbI<sub>3</sub> QDs with a size of ∼5 nm are treated in sequential steps using the ligands of 1-hydroxy-3-phenylpropan-2-aminium iodide (HPAI) and tributylsulfonium iodide (TBSI), respectively. The CsPbI<sub>3</sub> QD films exhibit improved optoelectronic properties, which enables the fabrication of a pure red PeLED with a peak external quantum efficiency (EQE) of 6.4% and a stable EL emission centered at the wavelength of 630 nm. Our reported sequential ligand post-treatment strategy opens a new route to improve the stability and efficiency of PeLEDs based on QDs.