Color-pure red light-emitting diodes based on two-dimensional lead-free perovskites

Abstract
It remains a central challenge to the information display community to develop red light-emitting diodes (LEDs) that meet demanding color coordinate requirements for wide color gamut displays. Here, we report high-efficiency, lead-free (PEA)2SnI4 perovskite LEDs (PeLEDs) with color coordinates (0.708, 0.292) that fulfill the Rec. 2100 specification for red emitters. Using valeric acid (VA)—which we show to be strongly coordinated to Sn—we slow the crystallization rate of the perovskite, improving the film morphology. The incorporation of VA also protects tin from undesired oxidation during the film-forming process. The improved films and the reduced Sn content enable PeLEDs with an external quantum efficiency of 5% and an operating half-life exceeding 15 hours at an initial brightness of 20 cd/m. This work illustrates the potential of Cd- and Pb-free PeLEDs for display technology.

Citation
Yuan, F., Zheng, X., Johnston, A., Wang, Y.-K., Zhou, C., Dong, Y., … Sargent, E. H. (2020). Color-pure red light-emitting diodes based on two-dimensional lead-free perovskites. Science Advances, 6(42), eabb0253. doi:10.1126/sciadv.abb0253

Acknowledgements
E.H.S. and all coauthors from the Department of Electrical and Computer Engineering at the University of Toronto acknowledge the financial support from the Ontario Research Fund–Research Excellence Program, the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Global Research Outreach program of Samsung Advanced Institute of Technology. Z.-H.L. and all coauthors from the Department of Materials Science and Engineering at the University of Toronto acknowledge the financial support from the NSERC (grant number 216956-12) and the National Natural Science Foundation of China (grant number 11774304). Computations were performed on the Niagara supercomputer at the SciNet HPC Consortium. SciNet is funded by the Canada Foundation for Innovation, the Government of Ontario, Ontario Research Fund–Research Excellence, and the University of Toronto.

Publisher
American Association for the Advancement of Science (AAAS)

Journal
Science Advances

DOI
10.1126/sciadv.abb0253

PubMed ID
33055155

PubMed Central ID
PMC7556835

Additional Links
https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.abb0253

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