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Title: Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification

Authors:
; ; ; ; ; ; ORCiD logo; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Advanced Solar Photophysics (CASP)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1388205
DOE Contract Number:
AC52-06NA25396
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nature Communications; Journal Volume: 8; Related Information: CASP partners with Los Alamos National Laboratory (lead); University of California, Irvine; University of Colorado; Colorado School of Mines; George Mason University; Los Alamos National Laboratory; University of Minnesota; National Renewable Energy Laboratory
Country of Publication:
United States
Language:
English
Subject:
solar (photovoltaic), solar (fuels), solid state lighting, bio-inspired, electrodes - solar, defects, charge transport, materials and chemistry by design, optics, synthesis (novel materials), synthesis (scalable processing)

Citation Formats

Kroupa, Daniel M., Vörös, Márton, Brawand, Nicholas P., McNichols, Brett W., Miller, Elisa M., Gu, Jing, Nozik, Arthur J., Sellinger, Alan, Galli, Giulia, and Beard, Matthew C.. Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification. United States: N. p., 2017. Web. doi:10.1038/ncomms15257.
Kroupa, Daniel M., Vörös, Márton, Brawand, Nicholas P., McNichols, Brett W., Miller, Elisa M., Gu, Jing, Nozik, Arthur J., Sellinger, Alan, Galli, Giulia, & Beard, Matthew C.. Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification. United States. doi:10.1038/ncomms15257.
Kroupa, Daniel M., Vörös, Márton, Brawand, Nicholas P., McNichols, Brett W., Miller, Elisa M., Gu, Jing, Nozik, Arthur J., Sellinger, Alan, Galli, Giulia, and Beard, Matthew C.. Tue . "Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification". United States. doi:10.1038/ncomms15257.
@article{osti_1388205,
title = {Tuning colloidal quantum dot band edge positions through solution-phase surface chemistry modification},
author = {Kroupa, Daniel M. and Vörös, Márton and Brawand, Nicholas P. and McNichols, Brett W. and Miller, Elisa M. and Gu, Jing and Nozik, Arthur J. and Sellinger, Alan and Galli, Giulia and Beard, Matthew C.},
abstractNote = {},
doi = {10.1038/ncomms15257},
journal = {Nature Communications},
number = ,
volume = 8,
place = {United States},
year = {Tue May 16 00:00:00 EDT 2017},
month = {Tue May 16 00:00:00 EDT 2017}
}
  • Band edge positions of semiconductors determine their functionality in many optoelectronic applications such as photovoltaics, photoelectrochemical cells and light emitting diodes. Here we show that band edge positions of lead sulfide (PbS) colloidal semiconductor nanocrystals, specifically quantum dots (QDs), can be tuned over 2.0 eV through surface chemistry modification. We achieved this remarkable control through the development of simple, robust and scalable solution-phase ligand exchange methods, which completely replace native ligands with functionalized cinnamate ligands, allowing for well-defined, highly tunable chemical systems. By combining experiments and ab initio simulations, we establish clear relationships between QD surface chemistry and the bandmore » edge positions of ligand/QD hybrid systems. We find that in addition to ligand dipole, inter-QD ligand shell inter-digitization contributes to the band edge shifts. As a result, we expect that our established relationships and principles can help guide future optimization of functional organic/inorganic hybrid nanostructures for diverse optoelectronic applications.« less
  • Band edge positions of semiconductors determine their functionality in many optoelectronic applications such as photovoltaics, photoelectrochemical cells and light emitting diodes. Here we show that band edge positions of lead sulfide (PbS) colloidal semiconductor nanocrystals, specifically quantum dots (QDs), can be tuned over 2.0 eV through surface chemistry modification. We achieved this remarkable control through the development of simple, robust and scalable solution-phase ligand exchange methods, which completely replace native ligands with functionalized cinnamate ligands, allowing for well-defined, highly tunable chemical systems. By combining experiments and ab initio simulations, we establish clear relationships between QD surface chemistry and the bandmore » edge positions of ligand/QD hybrid systems. We find that in addition to ligand dipole, inter-QD ligand shell inter-digitization contributes to the band edge shifts. We expect that our established relationships and principles can help guide future optimization of functional organic/inorganic hybrid nanostructures for diverse optoelectronic applications.« less
  • Colloidal quantum dots (CQDs) have received recent attention for low cost, solution processable, high efficiency solid-state photovoltaic devices due to the possibility of tailoring their optoelectronic properties by tuning size, composition, and surface chemistry. However, the device performance is limited by the diffusion length of charge carriers due to recombination. In this work, we show that band engineering of PbS QDs is achievable by changing the dipole moment of the passivating ligand molecules surrounding the QD. The valence band maximum and conduction band minimum of PbS QDs passivated with three different thiophenol ligands (4-nitrothiophenol, 4-fluorothiophenol, and 4-methylthiophenol) are determined bymore » UV–visible absorption spectroscopy and photoelectron spectroscopy in air (PESA), and the experimental results are compared with DFT calculations. These band-engineered QDs have been used to fabricate heterojunction solar cells in both unidirectional and bidirectional configurations. The results show that proper band alignment can improve the directionality of charge carrier collection to benefit the photovoltaic performance.« less