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Joo E, Hur JW, Ko JY, Kim TG, Hwang JY, Smith KE, Lee H, Cho SW. Effects of HAT-CN Layer Thickness on Molecular Orientation and Energy-Level Alignment with ZnPc. Molecules 2023; 28:molecules28093821. [PMID: 37175231 PMCID: PMC10179936 DOI: 10.3390/molecules28093821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Efficient energy-level alignment is crucial for achieving high performance in organic electronic devices. Because the electronic structure of an organic semiconductor is significantly influenced by its molecular orientation, comprehensively understanding the molecular orientation and electronic structure of the organic layer is essential. In this study, we investigated the interface between a 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) hole injection layer and a zinc-phthalocyanine (ZnPc) p-type organic semiconductor. To determine the energy-level alignment and molecular orientation, we conducted in situ ultraviolet and X-ray photoelectron spectroscopies, as well as angle-resolved X-ray absorption spectroscopy. We found that the HAT-CN molecules were oriented relatively face-on (40°) in the thin (5 nm) layer, whereas they were oriented relatively edge-on (62°) in the thick (100 nm) layer. By contrast, ZnPc orientation was not significantly altered by the underlying HAT-CN orientation. The highest occupied molecular orbital (HOMO) level of ZnPc was closer to the Fermi level on the 100 nm thick HAT-CN layer than on the 5 nm thick HAT-CN layer because of the higher work function. Consequently, a considerably low energy gap between the lowest unoccupied molecular orbital level of HAT-CN and the HOMO level of ZnPc was formed in the 100 nm thick HAT-CN case. This may improve the hole injection ability of the anode system, which can be utilized in various electronic devices.
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Affiliation(s)
- Eunah Joo
- Department of Physics and Engineering Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si 26493, Republic of Korea
| | - Jin Woo Hur
- Department of Physics and Engineering Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si 26493, Republic of Korea
| | - Joon Young Ko
- Department of Physics and Engineering Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si 26493, Republic of Korea
| | - Tae Gyun Kim
- Department of Physics and Engineering Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si 26493, Republic of Korea
| | - Jung Yeon Hwang
- Department of Physics and Engineering Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si 26493, Republic of Korea
| | - Kevin E Smith
- Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - Hyunbok Lee
- Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, 1 Gangwondaehak-gil, Chuncheon-si 24341, Republic of Korea
| | - Sang Wan Cho
- Department of Physics and Engineering Physics, Yonsei University, 1 Yonseidae-gil, Wonju-si 26493, Republic of Korea
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Li M, Zajaczkowski W, Velpula G, Jänsch D, Graf R, Marszalek T, Parekh SH, Zagranyarski Y, Mali K, Wagner M, De Feyter S, Li C, Müllen K, Pisula W. Transformation from helical to layered supramolecular organization of asymmetric perylene diimides via multiple intermolecular hydrogen bonding. Chem Sci 2020. [DOI: 10.1039/d0sc01911a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The solid-state supramolecular organization of asymmetric perylene diimide is transformed from helical to layered self-assembly after thermal annealing.
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Yin X, Wang Q, Zheng YJ, Song Z, Bin Hassan MH, Qi D, Wu J, Rusydi A, Wee ATS. Molecular Alignment and Electronic Structure of N,N'-Dibutyl-3,4,9,10-perylene-tetracarboxylic-diimide Molecules on MoS 2 Surfaces. ACS APPLIED MATERIALS & INTERFACES 2017; 9:5566-5573. [PMID: 28157294 DOI: 10.1021/acsami.6b14000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The molecular orientation of organic semiconductors on a solid surface could be an indispensable factor to determine the electrical performance of organic-based devices. Despite its fundamental prominence, a clear description of the emergent two-dimensional layered material-organic interface is not fully understood yet. In this study, we reveal the molecular alignment and electronic structure of thermally deposited N,N'-dibutyl-3,4,9,10-perylene-dicarboximide (PTCDI-C4) molecules on natural molybdenum disulfide (MoS2) using near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The average tilt angle determination reveals that the anisotropy in the π* symmetry transition of the carbon K-edge (284-288 eV range) is present at the sub-monolayer regime. Supported by ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), and resonant photoemission spectroscopy (RPES) measurements, we find that our spectroscopic measurements indicate a weak charge transfer established at the PTCDI-C4/MoS2 interface. Sterical hindrance due to the C4 alkyl chain caused tilting of the molecular plane at the initial thin film deposition. Our result shows a tunable interfacial alignment of organic molecules on transition metal dichalcogenide surfaces effectively enhancing the electronic properties of hybrid organic-inorganic heterostructure devices.
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Affiliation(s)
- Xinmao Yin
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
- Singapore Synchrotron Light Source, National University of Singapore , 5 Research Link, Singapore 1176033
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University , Shenzhen 518060, China
| | - Qixing Wang
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
| | - Yu J Zheng
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
| | - Zhibo Song
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
| | - Mohammad H Bin Hassan
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
| | - Dianyu Qi
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
| | - Jishan Wu
- Department of Chemistry, National University of Singapore , 3 Science Drive 3, 117543 Singapore
| | - Andrivo Rusydi
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
- Singapore Synchrotron Light Source, National University of Singapore , 5 Research Link, Singapore 1176033
- NUSNNI-NanoCore, National University of Singapore , Singapore 117411
| | - Andrew T S Wee
- Department of Physics, National University of Singapore , 2 Science Drive 3, 117542 Singapore
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