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dc.contributor.authorChen, Chen
dc.contributor.authorJoshi, Trinity
dc.contributor.authorLi, Huifang
dc.contributor.authorChavez, Anton D.
dc.contributor.authorPedramrazi, Zahra
dc.contributor.authorLiu, Pei-Nian
dc.contributor.authorLi, Hong
dc.contributor.authorDichtel, William R.
dc.contributor.authorBredas, Jean-Luc
dc.contributor.authorCrommie, Michael F.
dc.date.accessioned2018-02-01T07:25:00Z
dc.date.available2018-02-01T07:25:00Z
dc.date.issued2017-12-26
dc.identifier.citationChen C, Joshi T, Li H, Chavez AD, Pedramrazi Z, et al. (2017) Local Electronic Structure of a Single-Layer Porphyrin-Containing Covalent Organic Framework. ACS Nano 12: 385–391. Available: http://dx.doi.org/10.1021/acsnano.7b06529.
dc.identifier.issn1936-0851
dc.identifier.issn1936-086X
dc.identifier.pmid29261279
dc.identifier.doi10.1021/acsnano.7b06529
dc.identifier.urihttp://hdl.handle.net/10754/626973
dc.description.abstractWe have characterized the local electronic structure of a porphyrin-containing single-layer covalent organic framework (COF) exhibiting a square lattice. The COF monolayer was obtained by the deposition of 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (DMA) and 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) onto a Au(111) surface in ultrahigh vacuum followed by annealing to facilitate Schiff-base condensations between monomers. Scanning tunneling spectroscopy (STS) experiments conducted on isolated TAPP precursor molecules and the covalently linked COF networks yield similar transport (HOMO-LUMO) gaps of 1.85 ± 0.05 eV and 1.98 ± 0.04 eV, respectively. The COF orbital energy alignment, however, undergoes a significant downward shift compared to isolated TAPP molecules due to the electron-withdrawing nature of the imine bond formed during COF synthesis. Direct imaging of the COF local density of states (LDOS) via dI/dV mapping reveals that the COF HOMO and LUMO states are localized mainly on the porphyrin cores and that the HOMO displays reduced symmetry. DFT calculations reproduce the imine-induced negative shift in orbital energies and reveal that the origin of the reduced COF wave function symmetry is a saddle-like structure adopted by the porphyrin macrocycle due to its interactions with the Au(111) substrate.
dc.description.sponsorshipThis research was supported by the Army Research Office Multidisciplinary University Research Initiative (MURI) program under Grant No. W911NF-15-1-0447 (STM spectroscopy, precursor synthesis), by the Army Research Office Grant No. W911NF-17-1-0339 to Georgia Tech (DFT calculations), and by the U.S. Department of Energy, Office of Basic Energy Sciences, Nanomachine Program under Contract No. DEAC02-05CH11231 (sample preparation). The KAUST IT Research Computing Team and the KAUST Supercomputing Laboratory are gratefully acknowledged for providing generous computational resources for part of our theoretical work. T.J. acknowledges support from NSF Graduate Research Fellowship Program under Grant No. DGE 1106400. A.D.C. acknowledges support from the NDSEG Fellowship Program.
dc.publisherAmerican Chemical Society (ACS)
dc.relation.urlhttp://pubs.acs.org/doi/10.1021/acsnano.7b06529
dc.subjectPorphyrin
dc.subjectDensity functional theory
dc.subjectelectronic structure
dc.subjectScanning Tunneling Microscopy And Spectroscopy
dc.subjectCovalent Organic Framework
dc.titleLocal Electronic Structure of a Single-Layer Porphyrin-Containing Covalent Organic Framework
dc.typeArticle
dc.contributor.departmentKAUST Solar Center (KSC)
dc.contributor.departmentLaboratory for Computational and Theoretical Chemistry of Advanced Materials
dc.contributor.departmentMaterial Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalACS Nano
dc.contributor.institutionDepartment of Chemistry, University of California at Berkeley, Berkeley, California 94720, United States
dc.contributor.institutionDepartment of Physics, University of California at Berkeley, Berkeley, California 94720, United States
dc.contributor.institutionDepartment of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
dc.contributor.institutionDepartment of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
dc.contributor.institutionShanghai Key Laboratory of Functional Materials Chemistry and School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
dc.contributor.institutionSchool of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, United States
dc.contributor.institutionKavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
dc.contributor.institutionMaterials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
kaust.personLi, Huifang
kaust.personLi, Hong
kaust.personBredas, Jean-Luc
dc.date.published-online2017-12-26
dc.date.published-print2018-01-23


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