Mixed-Halide Perovskites with Stabilized Bandgaps

Zhengguo Xiao, Lianfeng Zhao, Nhu L. Tran, Yunhui Lisa Lin, Scott H. Silver, Ross A. Kerner, Nan Yao, Antoine Kahn, Gregory D. Scholes, Barry P. Rand

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)6863-6869
Number of pages7
JournalNano Letters
Volume17
Issue number11
DOIs
StatePublished - Nov 8 2017

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Keywords

  • LEDs
  • Mixed-halide perovskite
  • halide migration
  • phase separation
  • solar cells

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