@article{e8d159aba31c429f84af17255c3fb0e5,
title = "Mixed-Halide Perovskites with Stabilized Bandgaps",
abstract = "One merit of organic-inorganic hybrid perovskites is their tunable bandgap by adjusting the halide stoichiometry, an aspect critical to their application in tandem solar cells, wavelength-tunable light emitting diodes (LEDs), and lasers. However, the phase separation of mixed-halide perovskites caused by light or applied bias results in undesirable recombination at iodide-rich domains, meaning open-circuit voltage (VOC) pinning in solar cells and infrared emission in LEDs. Here, we report an approach to suppress halide redistribution by self-assembled long-chain organic ammonium capping layers at nanometer-sized grain surfaces. Using the stable mixed-halide perovskite films, we are able to fabricate efficient and wavelength-tunable perovskite LEDs from infrared to green with high external quantum efficiencies of up to 5%, as well as linearly tuned VOC from 1.05 to 1.45 V in solar cells.",
keywords = "LEDs, Mixed-halide perovskite, halide migration, phase separation, solar cells",
author = "Zhengguo Xiao and Lianfeng Zhao and Tran, {Nhu L.} and Lin, {Yunhui Lisa} and Silver, {Scott H.} and Kerner, {Ross A.} and Nan Yao and Antoine Kahn and Scholes, {Gregory D.} and Rand, {Barry P.}",
note = "Funding Information: *Address: Department of Electrical Engineering, and Andlinger Center for Energy and the Environment Princeton University, Princeton, New Jersey 08544, United States. E-mail: brand@ princeton.edu. ORCID Yunhui Lisa Lin: 0000-0002-0817-8757 Gregory D. Scholes: 0000-0003-3336-7960 Barry P. Rand: 0000-0003-4409-8751 Author Contributions Z.X. and B.P.R. designed the experiments. Z.X. fabricated and characterized the solar cells and LEDs, and performed the PL and absorption measurements. L.Z. conducted the XRD, SEM, and TEM measurements. N.Y. helped on the SEM and TEM measurement. N.T. and G.S. conducted the TRPL measurements. Z.X. and Y.L. did the EQE measurements. S.S. and A.K. conducted the UPS measurements. R.A.K. synthesized the precursors. B.P.R. supervised the work. Z.X. and B.P.R. wrote the manuscript. All authors read and commented on the manuscript. Funding We acknowledge a DARPA Young Faculty Award (Award #D15AP00093) and the ONR Young Investigator Program (Award #N00014-17-1-2005) for research funding. B.P.R. also acknowledges the support of a DuPont Young Professor Award. Notes The authors declare no competing financial interest. Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",
year = "2017",
month = nov,
day = "8",
doi = "10.1021/acs.nanolett.7b03179",
language = "English (US)",
volume = "17",
pages = "6863--6869",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "11",
}