Reduction of the Work Function of Gold by N-Heterocyclic Carbenes

Handle URI:
http://hdl.handle.net/10754/623900
Title:
Reduction of the Work Function of Gold by N-Heterocyclic Carbenes
Authors:
Kim, Hye Kyung; Hyla, Alexander S.; Winget, Paul; Li, Hong; Wyss, Chelsea M.; Jordan, Abraham J.; Larrain, Felipe A.; Sadighi, Joseph P. ( 0000-0003-1304-1170 ) ; Fuentes-Hernandez, Canek; Kippelen, Bernard; Bredas, Jean-Luc ( 0000-0001-7278-4471 ) ; Barlow, Stephen; Marder, Seth R. ( 0000-0001-6921-2536 )
Abstract:
N-Heterocyclic carbenes (NHCs) bind strongly to gold and other metals. This work experimentally probes the effect of NHCs on the work function (WF) of gold for the first time, theoretically analyzes the origin of this effect, and examines the effectiveness of NHC-modified gold as an electron-injecting electrode. UV photoelectron spectroscopy shows the WF of planar gold is reduced by nearly 2 eV to values of 3.3–3.5 eV. This effect is seen for NHCs with various heterocyclic cores, and with either small or large N,N′-substituents. DFT calculations indicate the WF reduction results from both the interface dipole formed between the NHC and the gold and from the NHC molecular dipole. For N,N′-diisopropyl-NHCs, an important contributor to the former is charge transfer associated with coordination of the carbene carbon atom to gold. In contrast, the carbene carbon of N,N′-2,6-diisopropylphenyl-NHCs is not covalently bound to gold, resulting in a lower interface dipole; however, a larger molecular dipole partially compensates for this. Single-layer C60 diodes with NHC-modified gold as the bottom electrode demonstrate high rectification ratios and show that these electrodes can act as effective electron-injecting contacts, suggesting they may be useful for a variety of materials applications.
KAUST Department:
KAUST Solar Center (KSC); Physical Sciences and Engineering (PSE) Division
Citation:
Kim HK, Hyla AS, Winget P, Li H, Wyss CM, et al. (2017) Reduction of the Work Function of Gold by N-Heterocyclic Carbenes. Chemistry of Materials 29: 3403–3411. Available: http://dx.doi.org/10.1021/acs.chemmater.6b04213.
Publisher:
American Chemical Society (ACS)
Journal:
Chemistry of Materials
Issue Date:
12-Apr-2017
DOI:
10.1021/acs.chemmater.6b04213
Type:
Article
ISSN:
0897-4756; 1520-5002
Sponsors:
The research was partly supported by the National Science Foundation (NSF) under the CCI Center for Selective C–H Functionalization, Grant CHE-1205646, the IGERT: Nanostructured Materials for Energy Storage and Conversion, Grant DGE-1069138, and the CRIF Program, Grant CHE-0946869. We also acknowledge generous support from KAUST; we thank the IT Research Computing Team and Supercomputing Laboratory at KAUST for providing computational and storage resources. B.K., F.A.L., and C.F.-H. acknowledge support from the Office of Naval Research Award N00014-04-1-0313.
Additional Links:
http://pubs.acs.org/doi/full/10.1021/acs.chemmater.6b04213
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorKim, Hye Kyungen
dc.contributor.authorHyla, Alexander S.en
dc.contributor.authorWinget, Paulen
dc.contributor.authorLi, Hongen
dc.contributor.authorWyss, Chelsea M.en
dc.contributor.authorJordan, Abraham J.en
dc.contributor.authorLarrain, Felipe A.en
dc.contributor.authorSadighi, Joseph P.en
dc.contributor.authorFuentes-Hernandez, Caneken
dc.contributor.authorKippelen, Bernarden
dc.contributor.authorBredas, Jean-Lucen
dc.contributor.authorBarlow, Stephenen
dc.contributor.authorMarder, Seth R.en
dc.date.accessioned2017-05-31T11:23:12Z-
dc.date.available2017-05-31T11:23:12Z-
dc.date.issued2017-04-12en
dc.identifier.citationKim HK, Hyla AS, Winget P, Li H, Wyss CM, et al. (2017) Reduction of the Work Function of Gold by N-Heterocyclic Carbenes. Chemistry of Materials 29: 3403–3411. Available: http://dx.doi.org/10.1021/acs.chemmater.6b04213.en
dc.identifier.issn0897-4756en
dc.identifier.issn1520-5002en
dc.identifier.doi10.1021/acs.chemmater.6b04213en
dc.identifier.urihttp://hdl.handle.net/10754/623900-
dc.description.abstractN-Heterocyclic carbenes (NHCs) bind strongly to gold and other metals. This work experimentally probes the effect of NHCs on the work function (WF) of gold for the first time, theoretically analyzes the origin of this effect, and examines the effectiveness of NHC-modified gold as an electron-injecting electrode. UV photoelectron spectroscopy shows the WF of planar gold is reduced by nearly 2 eV to values of 3.3–3.5 eV. This effect is seen for NHCs with various heterocyclic cores, and with either small or large N,N′-substituents. DFT calculations indicate the WF reduction results from both the interface dipole formed between the NHC and the gold and from the NHC molecular dipole. For N,N′-diisopropyl-NHCs, an important contributor to the former is charge transfer associated with coordination of the carbene carbon atom to gold. In contrast, the carbene carbon of N,N′-2,6-diisopropylphenyl-NHCs is not covalently bound to gold, resulting in a lower interface dipole; however, a larger molecular dipole partially compensates for this. Single-layer C60 diodes with NHC-modified gold as the bottom electrode demonstrate high rectification ratios and show that these electrodes can act as effective electron-injecting contacts, suggesting they may be useful for a variety of materials applications.en
dc.description.sponsorshipThe research was partly supported by the National Science Foundation (NSF) under the CCI Center for Selective C–H Functionalization, Grant CHE-1205646, the IGERT: Nanostructured Materials for Energy Storage and Conversion, Grant DGE-1069138, and the CRIF Program, Grant CHE-0946869. We also acknowledge generous support from KAUST; we thank the IT Research Computing Team and Supercomputing Laboratory at KAUST for providing computational and storage resources. B.K., F.A.L., and C.F.-H. acknowledge support from the Office of Naval Research Award N00014-04-1-0313.en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/full/10.1021/acs.chemmater.6b04213en
dc.titleReduction of the Work Function of Gold by N-Heterocyclic Carbenesen
dc.typeArticleen
dc.contributor.departmentKAUST Solar Center (KSC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalChemistry of Materialsen
dc.contributor.institutionSchool of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United Statesen
dc.contributor.institutionCenter for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United Statesen
dc.contributor.institutionSchool of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0250, United Statesen
kaust.authorHyla, Alexander S.en
kaust.authorLi, Hongen
kaust.authorBredas, Jean-Lucen
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