ja9b12323_si_001.pdf (5.63 MB)
Chloride Insertion–Immobilization Enables Bright, Narrowband, and Stable Blue-Emitting Perovskite Diodes
journal contribution
posted on 2020-03-09, 18:41 authored by Dongxin Ma, Petar Todorović, Shadi Meshkat, Makhsud I. Saidaminov, Ya-Kun Wang, Bin Chen, Peicheng Li, Benjamin Scheffel, Rafael Quintero-Bermudez, James Z. Fan, Yitong Dong, Bin Sun, Chao Xu, Chun Zhou, Yi Hou, Xiyan Li, Yuetong Kang, Oleksandr Voznyy, Zheng-Hong Lu, Dayan Ban, Edward H. SargentMetal halide perovskites
show promise for light-emitting diodes
(LEDs) owing to their facile manufacture and excellent optoelectronic
performance, including high color purity and spectral stability, especially
in the green region. However, for blue perovskite LEDs, the emission
spectrum line width is broadened to over 25 nm by the coexistence
of multiple reduced-dimensional perovskite domains, and the spectral
stability is poor, with an undesirable shift (over 7 nm) toward longer
wavelengths under operating conditions, degradation that occurs due
to phase separation when mixed halides are employed. Here we demonstrate
chloride insertion-immobilization, a strategy that enables blue perovskite
LEDs, the first to exhibit narrowband (line width of 18 nm) and spectrally
stable (no wavelength shift) performance. We prepare bromide-based
perovskites and then employ organic chlorides for dynamic treatment,
inserting and in situ immobilizing chlorides to blue-shift
and stabilize the emission. We achieve sky-blue LEDs with a record
luminance over 5100 cd/m2 at 489 nm, and an operating half-life
of 51 min at 1500 cd/m2. By device structure optimization,
we further realize an improved EQE of 5.2% at 479 nm and an operating
half-life of 90 min at 100 cd/m2.