Phase-Transfer Ligand Exchange of Lead Chalcogenide Quantum Dots for Direct Deposition of Thick, Highly Conductive Films

Qianglu Lin, Hyeong Jin Yun, Wenyong Liu, Hyung Jun Song, Nikolay S. Makarov, Oleksandr Isaienko, Tom Nakotte, Gen Chen, Hongmei Luo, Victor I Klimov, Jeffrey M. Pietryga

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The use of semiconductor nanocrystal quantum dots (QDs) in optoelectronic devices typically requires postsynthetic chemical surface treatments to enhance electronic coupling between QDs and allow for efficient charge transport in QD films. Despite their importance in solar cells and infrared (IR) light-emitting diodes and photodetectors, advances in these chemical treatments for lead chalcogenide (PbE; E = S, Se, Te) QDs have lagged behind those of, for instance, II-VI semiconductor QDs. Here, we introduce a method for fast and effective ligand exchange for PbE QDs in solution, resulting in QDs completely passivated by a wide range of small anionic ligands. Due to electrostatic stabilization, these QDs are readily dispersible in polar solvents, in which they form highly concentrated solutions that remain stable for months. QDs of all three Pb chalcogenides retain their photoluminescence, allowing for a detailed study of the effect of the surface ionic double layer on electronic passivation of QD surfaces, which we find can be explained using the hard/soft acid-base theory. Importantly, we prepare highly conductive films of PbS, PbSe, and PbTe QDs by directly casting from solution without further chemical treatment, as determined by field-effect transistor measurements. This method allows for precise control over the surface chemistry, and therefore the transport properties of deposited films. It also permits single-step deposition of films of unprecedented thickness via continuous processing techniques, as we demonstrate by preparing a dense, smooth, 5.3-μm-thick PbSe QD film via doctor-blading. As such, it offers important advantages over laborious layer-by-layer methods for solar cells and photodetectors, while opening the door to new possibilities in ionizing-radiation detectors.

Original languageEnglish
Pages (from-to)6644-6653
Number of pages10
JournalJournal of the American Chemical Society
Volume139
Issue number19
DOIs
Publication statusPublished - May 17 2017

Fingerprint

Quantum Dots
Conductive films
Thick films
Semiconductor quantum dots
Lead
Ligands
Photodetectors
Solar cells
Chalcogenides
Radiation detectors
Semiconductors
Ionizing radiation
Field effect transistors
Surface chemistry
Passivation
Optoelectronic devices
Ionizing Radiation
Transport properties
Nanocrystals
Static Electricity

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Phase-Transfer Ligand Exchange of Lead Chalcogenide Quantum Dots for Direct Deposition of Thick, Highly Conductive Films. / Lin, Qianglu; Yun, Hyeong Jin; Liu, Wenyong; Song, Hyung Jun; Makarov, Nikolay S.; Isaienko, Oleksandr; Nakotte, Tom; Chen, Gen; Luo, Hongmei; Klimov, Victor I; Pietryga, Jeffrey M.

In: Journal of the American Chemical Society, Vol. 139, No. 19, 17.05.2017, p. 6644-6653.

Research output: Contribution to journalArticle

Lin, Q, Yun, HJ, Liu, W, Song, HJ, Makarov, NS, Isaienko, O, Nakotte, T, Chen, G, Luo, H, Klimov, VI & Pietryga, JM 2017, 'Phase-Transfer Ligand Exchange of Lead Chalcogenide Quantum Dots for Direct Deposition of Thick, Highly Conductive Films', Journal of the American Chemical Society, vol. 139, no. 19, pp. 6644-6653. https://doi.org/10.1021/jacs.7b01327
Lin, Qianglu ; Yun, Hyeong Jin ; Liu, Wenyong ; Song, Hyung Jun ; Makarov, Nikolay S. ; Isaienko, Oleksandr ; Nakotte, Tom ; Chen, Gen ; Luo, Hongmei ; Klimov, Victor I ; Pietryga, Jeffrey M. / Phase-Transfer Ligand Exchange of Lead Chalcogenide Quantum Dots for Direct Deposition of Thick, Highly Conductive Films. In: Journal of the American Chemical Society. 2017 ; Vol. 139, No. 19. pp. 6644-6653.
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