Electroluminescence efficiencies and stabilities of quasi-two-dimensional halide perovskites are restricted by the formation of multiple-quantum-well structures with broad and uncontrollable phase distributions. Here, we report a ligand design strategy to substantially suppress diffusion-limited phase disproportionation, thereby enabling better phase control. We demonstrate that extending the π-conjugation length and increasing the cross-sectional area of the ligand enables perovskite thin films with dramatically suppressed ion transport, narrowed phase distributions, reduced defect densities, and enhanced radiative recombination efficiencies. Consequently, we achieved efficient and stable deep-red light-emitting diodes with a peak external quantum efficiency of 26.3% (average 22.9% among 70 devices and cross-checked) and a half-life of ~220 and 2.8 h under a constant current density of 0.1 and 12 mA/cm2, respectively. Our devices also exhibit wide wavelength tunability and improved spectral and phase stability compared with existing perovskite light-emitting diodes. These discoveries provide critical insights into the molecular design and crystallization kinetics of low-dimensional perovskite semiconductors for light-emitting devices.
|State||Published - Dec 2023|
Bibliographical noteFunding Information:
This work is supported by the National Science Foundation (Grant No. 2131608-ECCS). Z.Z. and H.G. acknowledge the support from the National Science Foundation (2110814-EPM). L.J. and L.H. acknowledge the support for spectroscopy measurements from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0022082. H.R.A. and K.R.G. acknowledge the support for UPS measurements from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0018208. X.M. acknowledges the financial support by the National Natural Science Foundation of China (No. 11774188). A.B. and S.C. acknowledge the support from the ONR MURI (N00014-21-1-2026). ToF-SIMS analysis was carried out with support provided by the National Science Foundation CBET-1626418 and this work was conducted in part using resources of the Shared Equipment Authority at Rice University. We thank Dr. Shuchen Zhang and Qian Lu for the discussions and help with device fabrications, respectively.
© 2023, The Author(s).
ASJC Scopus subject areas
- Chemistry (all)
- Biochemistry, Genetics and Molecular Biology (all)
- Physics and Astronomy (all)