Spectrally Stable and Efficient Pure Red CsPbI<sub>3</sub> Quantum Dot Light-Emitting Diodes Enabled by Sequential Ligand Post-Treatment Strategy
Yi‐Feng Lan, Jisong Yao, Jun‐Nan Yang, Yong‐Hui Song, Xue‐Chen Ru, Qian Zhang, Li‐Zhe Feng, Tian Chen, Kuang‐Hui Song, Hong‐Bin Yao
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 CsPbI3 quantum dots (QDs). The synthesized CsPbI3 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 CsPbI3 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.