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 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 approximate to 98%) narrow-band (FWHM approximate to 43 nm) green emission and high thermal stability (97%@150 degrees 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 approximate to 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. Eu(II)-based iodide hybrids exhibit an unprecedented narrow-band (full width at half maxima FWHM approximate to 43 nm) green emission with high PLQY (98%) and high thermal stability (97%@150 degrees C). The pc-LEDs using Eu(II)-based iodide hybrids exhibit a maximum brightness of approximate to 396 000 cd m-2, photoelectric efficiency of 29.2%, and ultra-high pixel resolution of 2540 PPI. image