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Giant Light-Emission Enhancement in Lead Halide Perovskites by Surface Oxygen Passivation.

  • Author(s): Lu, Dylan
  • Zhang, Ye
  • Lai, Minliang
  • Lee, Alex
  • Xie, Chenlu
  • Lin, Jia
  • Lei, Teng
  • Lin, Zhenni
  • Kley, Christopher S
  • Huang, Jianmei
  • Rabani, Eran
  • Yang, Peidong
  • et al.
Abstract

Surface condition plays an important role in the optical performance of semiconductor materials. As new types of semiconductors, the emerging metal-halide perovskites are promising for next-generation optoelectronic devices. We discover significantly improved light-emission efficiencies in lead halide perovskites due to surface oxygen passivation. The enhancement manifests close to 3 orders of magnitude as the perovskite dimensions decrease to the nanoscale, improving external quantum efficiencies from <0.02% to over 12%. Along with about a 4-fold increase in spontaneous carrier recombination lifetimes, we show that oxygen exposure enhances light emission by reducing the nonradiative recombination channel. Supported by X-ray surface characterization and theoretical modeling, we propose that excess lead atoms on the perovskite surface create deep-level trap states that can be passivated by oxygen adsorption.

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