Abstract
Surface ligands enable control over the dispersibility of colloidal quantum dots (CQDs) via steric and electrostatic stabilization. Today’s device-grade CQD inks have consistently relied on highly polar solvents: this enables facile single-step deposition of multi-hundred-nanometer-thick CQD films; but it prevents the realization of CQD film stacks made up of CQDs having different compositions, since polar solvents redisperse underlying films. Here we introduce aromatic ligands to achieve process-orthogonal CQD inks, and enable thereby multifunctional multilayer CQD solids. We explore the effect of the anchoring group of the aromatic ligand on the solubility of CQD inks in weakly-polar solvents, and find that a judicious selection of the anchoring group induces a dipole that provides additional CQD-solvent interactions. This enables colloidal stability without relying on bulky insulating ligands. We showcase the benefit of this ink as the hole transport layer in CQD optoelectronics, achieving an external quantum efficiency of 84% at 1210 nm.
Original language | English (US) |
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Article number | 4814 |
Journal | Nature communications |
Volume | 11 |
Issue number | 1 |
DOIs | |
State | Published - Dec 1 2020 |
Funding
This work was supported by Ontario Research Fund—Research Excellence program (ORF7 Ministry of Research and Innovation, Ontario Research Fund–Research Excellence Round 7), and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. Computations were performed on the Niagara supercomputer at the SciNet HPC Consortium. SciNet is funded by: the Canada Foundation for Innovation; the Government of Ontario; Ontario Research Fund—Research Excellence; and the University of Toronto. This research was also supported by the National Research Foundation (NRF) of Korea (NRF-2020R1A6A3A03038131). We thank D. Kopilovic, E. Palmiano, L. Levina, and R. Wolowiec for the technical support. The authors acknowledge the financial support from QD Solar Inc.
ASJC Scopus subject areas
- General Chemistry
- General Biochemistry, Genetics and Molecular Biology
- General Physics and Astronomy