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Zhang H, Dong H, Li Y, Jiang W, Zhen Y, Jiang L, Wang Z, Chen W, Wittmann A, Hu W. Novel Air Stable Organic Radical Semiconductor of Dimers of Dithienothiophene, Single Crystals, and Field-Effect Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:7466-7471. [PMID: 27322939 DOI: 10.1002/adma.201601502] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/09/2016] [Indexed: 06/06/2023]
Abstract
Singly linked and vinyl-linked dimers of dithienothiophenes exhibit different electronic behaviors. Single crystals of the singly linked dimer show a high conductivity of 0.265 S cm(-1) , five orders of magnitude higher than that of the vinyl-linked dimer. The huge increase in the hole density of singly linked dimers results from the formation of radicals, which can be reversibly tuned by facile thermal de-doping.
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Affiliation(s)
- Hantang Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Huanli Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yang Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wei Jiang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yonggang Zhen
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Lang Jiang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK.
| | - Zhaohui Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wei Chen
- Department of Chemistry and Department of Physics, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Angela Wittmann
- Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Wenping Hu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Sciences, Tianjin University, Tianjin, 300072, China.
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072, China.
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Nandy S, Maiti UN, Ghosh CK, Chattopadhyay KK. Enhanced p-type conductivity and band gap narrowing in heavily Al doped NiO thin films deposited by RF magnetron sputtering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:115804. [PMID: 21693930 DOI: 10.1088/0953-8984/21/11/115804] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Stoichiometric NiO, a Mott-Hubbard insulator at room temperature, shows p-type electrical conduction due to the introduction of Ni(2+) vacancies (V(Ni)('')) and self-doping of Ni(3+) ions in the presence of excess oxygen. The electrical conductivity of this important material is low and not sufficient for active device fabrication. Al doped NiO thin films were synthesized by radio frequency (RF) magnetron sputtering on glass substrates at a substrate temperature of 250 °C in an oxygen + argon atmosphere in order to enhance the p-type electrical conductivity. X-ray diffraction studies confirmed the correct phase formation and also oriented growth of NiO thin films. Al doping was confirmed by x-ray photoelectron spectroscopic studies. The structural, electrical and optical properties of the films were investigated as a function of Al doping (0-4 wt%) in the target. The room temperature electrical conductivity increased from 0.01-0.32 S cm (-1) for 0-4% Al doping. With increasing Al doping, above the Mott critical carrier density, energy band gap shrinkage was observed. This was explained by the shift of the band edges due to the existence of exchange and correlation energies amongst the electron-electron and hole-hole systems and also by the interaction between the impurity quasi-particle system.
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Affiliation(s)
- S Nandy
- Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata-700032, India
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Dekadjevi DT, Ryan PA, Hickey BJ, Fulthorpe BD, Tanner BK. Experimental evidence for electron channeling in Fe /Aau (100) superlattices. PHYSICAL REVIEW LETTERS 2001; 86:5787-5790. [PMID: 11415358 DOI: 10.1103/physrevlett.86.5787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2000] [Indexed: 05/23/2023]
Abstract
We present transport and structural data from epitaxial (100) and (111) Au/Fe superlattices grown by molecular beam epitaxy. From their analysis, we conclude that an electron channeling mechanism, due to strong specular reflection of the minority spin carrier at the Au/Fe interfaces, is responsible for the high conductivity in the (100) superlattices.
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Affiliation(s)
- D T Dekadjevi
- Department of Physics and Astronomy, E. C. Stoner Laboratory, University of Leeds, Leeds LS2 9JT, United Kingdom
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