Cited 28 time in webofscience Cited 29 time in scopus

Acid-Assisted Ligand Exchange Enhances Coupling in Colloidal Quantum Dot Solids

Title
Acid-Assisted Ligand Exchange Enhances Coupling in Colloidal Quantum Dot Solids
Authors
Jo, Jea WoongChoi, Jong Minde Arquer, F. Pelayo GarciaSeifitokaldani, AliSun, BinKim, YounghoonAhn, Hyung JuFan, JamesQuintero-Bermudez, RafaelKim, Jung HwanChoi, Min JaeBaek, Se WoongProppe, Andrew H.Walters, GrantNam, Dae-HyunKelley, ShanaHoogland, SjoerdVoznyy, OleksandrSargent, Edward H.
DGIST Authors
Kim, YounghoonNam, Dae-Hyun
Issue Date
2018-07
Citation
Nano Letters, 18(7), 4417-4423
Type
Article
Article Type
Article
Author Keywords
Colloidal quantum dotsphotovoltaicssolution-phase ligand exchangenarrow bandgapinfraredsurface passivation
Keywords
LIGHT-EMITTING-DIODESSOLAR-CELLSPBS NANOCRYSTALSINFRARED PHOTOVOLTAICSINKSSURFACESIZE
ISSN
1530-6984
Abstract
Colloidal quantum dots (CQDs) are promising solution-processed infrared-absorbing materials for optoelectronics. In these applications, it is crucial to replace the electrically insulating ligands used in synthesis to form strongly coupled quantum dot solids. Recently, solution-phase ligand-exchange strategies have been reported that minimize the density of defects and the polydispersity of CQDs; however, we find herein that the new ligands exhibit insufficient chemical reactivity to remove original oleic acid ligands completely. This leads to low CQD packing and correspondingly low electronic performance. Here we report an acid-assisted solution-phase ligand-exchange strategy that, by enabling efficient removal of the original ligands, enables the synthesis of densified CQD arrays. Our use of hydroiodic acid simultaneously facilitates high CQD packing via proton donation and CQD passivation through iodine. We demonstrate highly packed CQD films with a 2.5 times increased carrier mobility compared with prior exchanges. The resulting devices achieve the highest infrared photon-to-electron conversion efficiencies (>50%) reported in the spectral range of 0.8 to 1.1 eV. © 2018 American Chemical Society.
URI
http://hdl.handle.net/20.500.11750/9102
DOI
10.1021/acs.nanolett.8b01470
Publisher
American Chemical Society
Related Researcher
Files:
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Collection:
Division of Energy Technology1. Journal Articles
Department of Energy Science and EngineeringRenewable Energy Conversion Materials Laboratory1. Journal Articles


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