Narrow‐Band Green‐Emitting Hybrid Organic–Inorganic Eu (II)‐Iodides for Next‐Generation Micro‐LED Displays

Abstract

AbstractLow‐dimensional metal halide perovskites are an emerging class of light‐emitting materials for LED‐based displays; however, their B‐site cations are confined to ns2, d5, and d10 metals. Here, the design of divalent rare earth ions at B‐site is presented and a novel Eu(II)‐based iodide hybrid is reported 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. The Eu(II)‐based iodide hybrid is further demonstrated for color‐pure green phosphor‐converted LEDs with a maximum brightness of ≈396 000 cd m−2 and photoelectric efficiency of 29.2%. High‐resolution micrometer‐scale light‐emitting diode (micro‐LED) displays (2540 PPI) via the solution‐processed screen is also presented. This work thus showcases a compelling narrow‐band green emitter for commercial micro‐LED displays.