Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots

Yitong Dong, Ya Kun Wang, Fanglong Yuan, Andrew Johnston, Yuan Liu, Dongxin Ma, Min Jae Choi, Bin Chen, Mahshid Chekini, Se Woong Baek, Laxmi Kishore Sagar, James Fan, Yi Hou, Mingjian Wu, Seungjin Lee, Bin Sun, Sjoerd Hoogland, Rafael Quintero-Bermudez, Hinako Ebe, Petar TodorovicFilip Dinic, Peicheng Li, Hao Ting Kung, Makhsud I. Saidaminov, Eugenia Kumacheva, Erdmann Spiecker, Liang Sheng Liao, Oleksandr Voznyy, Zheng Hong Lu, Edward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

552 Scopus citations

Abstract

Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport1 and for applications in optoelectronics2. Forming high-quality QD solids—necessary for device fabrication—requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport3. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites4. Here we report perovskite QD resurfacing to achieve a bipolar shell consisting of an inner anion shell, and an outer shell comprised of cations and polar solvent molecules. The outer shell is electrostatically adsorbed to the negatively charged inner shell. This approach produces strongly confined perovskite QD solids that feature improved carrier mobility (≥0.01 cm2 V−1 s−1) and reduced trap density relative to previously reported low-dimensional perovskites. Blue-emitting QD films exhibit photoluminescence quantum yields exceeding 90%. By exploiting the improved mobility, we have been able to fabricate CsPbBr3 QD-based efficient blue and green light-emitting diodes. Blue devices with reduced trap density have an external quantum efficiency of 12.3%; the green devices achieve an external quantum efficiency of 22%.

Original languageEnglish (US)
Pages (from-to)668-674
Number of pages7
JournalNature nanotechnology
Volume15
Issue number8
DOIs
StatePublished - Aug 1 2020

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biomedical Engineering
  • General Materials Science

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