At present, electric lighting accounts for ~15% of global power consumption and thus the adoption of efficient, low-cost lighting technologies is important. Halide perovskites have been shown to be good emitters of pure red, green and blue light, but an efficient source of broadband white electroluminescence suitable for lighting applications is desirable. Here, we report a white light-emitting diode (LED) strategy based on solution-processed heterophase halide perovskites that, unlike GaN white LEDs, feature only one broadband emissive layer and no phosphor. Our LEDs operate with a peak luminance of 12,200 cd m−2 at a bias of 6.6 V and a maximum external quantum efficiency of 6.5% at a current density of 8.3 mA cm−2. Systematic in situ and ex situ characterizations reveal that the mechanism of efficient electroluminescence is charge injection into the α phase of CsPbI3, α to δ charge transfer and α–δ balanced radiative recombination. Future advances in fabrication technology and mechanistic understanding should lead to further improvements in device efficiency and luminance.
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The data that support the findings of this study are available from the corresponding author upon reasonable request. Source data are provided with this paper.
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This work at NJUST was supported financially by NSFC (61725402 and 51922049), the National ‘Ten Thousand Talents Plan’ leading talents (W03020394), the Six Top Talent Innovation teams of Jiangsu Province (TD-XCL-004), the Distinguished Scientist Fellowship Program (DSFP) at King Saud University, the Natural Science Foundation of Jiangsu Province (BK20190443 and BK20180020), the National Key Research and Development Program of China (2016YFB0401701), the Young Elite Scientists Sponsorship Program by Jiangsu CAST (JS19TJGC132574), Fundamental Research Funds for the Central Universities (30919011299, 30920032102 and 30919012107) and PAPD of Jiangsu Higher Education Institutions. The imaging work at the University of Washington (UW) is supported by the Department of Energy (DOE-SC0013957) and the bulk photoluminescence measurements at UW (PLQY, spectra and T-dependent spectra) were supported by the National Science Foundation (NSF MRSEC 1719797). J.W. acknowledges support from a Washington Research Foundation innovation fellowship and a Mistletoe Foundation research fellowship. We thank C. Zhang (NJU) for the transient absorption measurements, C.Y. Zhou from Enlitech for PL mapping measurements and Y. (Demi) Liu and C. Bischak from UW for help with low-temperature PL and fluorescence microscopy measurements. The synchrotron X-ray work used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated by Argonne National Laboratory under contract no. DEAC02-06CH11357.
The authors declare no competing interests.
Peer review information Nature Photonics thanks the anonymous reviewers for their contribution to the peer review of this work.
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Chen, J., Wang, J., Xu, X. et al. Efficient and bright white light-emitting diodes based on single-layer heterophase halide perovskites. Nat. Photonics 15, 238–244 (2021). https://doi.org/10.1038/s41566-020-00743-1
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