Fine-Tuning Crystal Structures of Lead Bromide Perovskite Nanocrystals through Trace Cadmium(II) Doping for Efficient Color-Saturated Green LEDs

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Jianfeng Zhang
  • Junhui Wang
  • Lei Cai
  • Sheng Wang
  • Kaifeng Wu
  • Baoquan Sun
  • Weitao Zheng
  • Stephen V. Kershaw
  • Guohua Jia
  • Xiaoyu Zhang
  • Xuyong Yang

Detail(s)

Original languageEnglish
Article numbere202403996
Journal / PublicationAngewandte Chemie - International Edition
Volume63
Issue number26
Online published28 Apr 2024
Publication statusPublished - 21 Jun 2024

Abstract

Decreasing perovskite nanocrystal size increases radiative recombination due to the quantum confinement effect, but also increases the Auger recombination rate which leads to carrier imbalance in the emitting layers of electroluminescent devices. Here, we overcome this trade-off by increasing the exciton effective mass without affecting the size, which is realized through the trace Cd2+ doping of formamidinium lead bromide perovskite nanocrystals. We observe an ~2.7 times increase in the exciton binding energy benefiting from a slight distortion of the [BX6]4− octahedra caused by doping in the case of that the Auger recombination rate is almost unchanged. As a result, bright color-saturated green emitting perovskite nanocrystals with a photoluminescence quantum yield of 96 % are obtained. Cd2+ doping also shifts up the energy levels of the nanocrystals, relative to the Fermi level so that heavily n-doped emitters convert into only slightly n-doped ones; this boosts the charge injection efficiency of the corresponding light-emitting diodes. The light-emitting devices based on those nanocrystals reached a high external quantum efficiency of 29.4 % corresponding to a current efficiency of 123 cd A−1, and showed dramatically improved device lifetime, with a narrow bandwidth of 22 nm and Commission Internationale de I'Eclairage coordinates of (0.20, 0.76) for color-saturated green emission for the electroluminescence peak centered at 534 nm, thus being fully compliant with the latest standard for wide color gamut displays. © 2024 Wiley-VCH GmbH.

Research Area(s)

  • auger recombination, cadmium (II) doping, exciton binding energy, light-emitting diode, perovskite nanocrystals

Citation Format(s)

Fine-Tuning Crystal Structures of Lead Bromide Perovskite Nanocrystals through Trace Cadmium(II) Doping for Efficient Color-Saturated Green LEDs. / Zhang, Jianfeng; Wang, Junhui; Cai, Lei et al.
In: Angewandte Chemie - International Edition, Vol. 63, No. 26, e202403996, 21.06.2024.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review