Effect of ethanolamine passivation of ZnO nanoparticles in quantum dot light emitting diode structure

Kyeongchan Noh, Minsu Kim, Sang Hyun Lee, Hwang Sik Yun, Tae Hyeon Lim, Yeongho Choi, Ki Ju Kim, Yiran Jiang, Keonwon Beom, Minju Kim, Young Gwang Kim, Pilwoo Lee, Nuri Oh, Bong Hoon Kim, Chansun Shin, Hyun Ho Lee, Tae Sik Yoon, Moonsub Shim, Jaehoon Lim, Ki Bum KimSeong Yong Cho

Research output: Contribution to journalArticlepeer-review


The aging of ZnO nanoparticles in quantum dot light-emitting diode (QD-LED) structures was studied. Coarsening of as-synthesized ZnO nanoparticles is observed in both solution and thin film structures, which potentially deteriorates the performance of QD-LED devices over time. First, the temperature effect on ZnO coarsening was investigated, and it was revealed that aging of ZnO nanoparticles is faster at higher temperature due to a diffusion-controlled mechanism of nanoparticle coarsening. To observe aggregation of ZnO in the film state, the electron transporting part (ZnO/Al) of the QD-LED structure was prepared. The current density of a ZnO film and an electron-only device (QD/ZnO between two electrodes) was also measured. Resistance of the film increased as a function of aging time, which corresponded with observations of the ZnO film by optical microscopy. Aggregation of ZnO nanoparticles was directly measured by the root-mean-square value using atomic force microscopy. Ethanolamine (EA) stabilizer was added to the ZnO solution to disperse the ZnO nanoparticles without aggregation. The effect of EA on the surface passivation of the ZnO found to suppress pinhole formation, as revealed by scanning electron microscopy observations. Finally, the device lifetime was measured for QD-LEDs with EA-stabilized ZnO to understand the effect of ZnO aging on long-term QD-LED device operation.

Original languageEnglish (US)
Pages (from-to)998-1005
Number of pages8
JournalCurrent Applied Physics
Issue number9
StatePublished - Sep 2019
Externally publishedYes


  • Aging
  • Coarsening
  • Ethanolamine
  • ZnO

ASJC Scopus subject areas

  • General Materials Science
  • General Physics and Astronomy


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