Facet-Oriented Coupling Enables Fast and Sensitive Colloidal Quantum Dot Photodetectors

Margherita Biondi, Min Jae Choi, Zhibo Wang, Mingyang Wei, Seungjin Lee, Hitarth Choubisa, Laxmi Kishore Sagar, Bin Sun, Se Woong Baek, Bin Chen, Petar Todorović, Amin Morteza Najarian, Armin Sedighian Rasouli, Dae Hyun Nam, Maral Vafaie, Yuguang C. Li, Koen Bertens, Sjoerd Hoogland, Oleksandr Voznyy, F. Pelayo García de ArquerEdward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Charge carrier transport in colloidal quantum dot (CQD) solids is strongly influenced by coupling among CQDs. The shape of as-synthesized CQDs results in random orientational relationships among facets in CQD solids, and this limits the CQD coupling strength and the resultant performance of optoelectronic devices. Here, colloidal-phase reconstruction of CQD surfaces, which improves facet alignment in CQD solids, is reported. This strategy enables control over CQD faceting and allows demonstration of enhanced coupling in CQD solids. The approach utilizes post-synthetic resurfacing and unites surface passivation and colloidal stability with a propensity for dots to couple via (100):(100) facets, enabling increased hole mobility. Experimentally, the CQD solids exhibit a 10× increase in measured hole mobility compared to control CQD solids, and enable photodiodes (PDs) exhibiting 70% external quantum efficiency (vs 45% for control devices) and specific detectivity, D* > 1012 Jones, each at 1550 nm. The photodetectors feature a 7 ns response time for a 0.01 mm2 area—the fastest reported for solution-processed short-wavelength infrared PDs.

Original languageEnglish (US)
Article number2101056
JournalAdvanced Materials
Issue number33
StatePublished - Aug 19 2021


  • colloidal atomic layer deposition
  • colloidal quantum dots
  • coupling
  • facets
  • photodetectors

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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