Narrow-Band Green-emitting Hybrid Organic-inorganic Eu (II)-iodides for Next-Generation Micro-LED Displays.

Low-dimensional metal halide perovskites are an emerging class of light-emitting materials for LED-based displays; however, their B-site cations are confined to ns 2 , d 5, and d 10 metals. Here, we present the design of rare earth ions at B-site and report a novel Eu(II)-based iodide hybrid with efficient (PLQY ∼ 98%) narrow-band (FWHM ∼ 43 nm) green emission and high thermal stability (97%@150 °C). Owing to reduced lattice vibrations and shrunken average distance of Eu(II)-iodide bonds in the face-sharing 1D-structure, photoluminescence from Eu(II) 4f-5d transition appears along with elevated crystal-field splitting of 5d energy level. We further demonstrate the Eu(II)-based iodide hybrid for color-pure green pc-LEDs with a maximum brightness of approximately 396,000 cd m -2 and photoelectric efficiency of 29.2%. We also present high-resolution micro-LED displays (2540 PPI) via the solution-processed screen. This work thus showcases a compelling narrow-band green emitter for commercial micro-LED displays. This article is protected by copyright. All rights reserved.