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Hahm SG, Ko YG, Rho Y, Ahn B, Ree M. Liquid crystal alignment in advanced flat-panel liquid crystal displays. Curr Opin Chem Eng 2013. [DOI: 10.1016/j.coche.2012.09.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Kim K, Yen HJ, Ko YG, Chang CW, Kwon W, Liou GS, Ree M. Electrically bistable digital memory behaviors of thin films of polyimides based on conjugated bis(triphenylamine) derivatives. POLYMER 2012. [DOI: 10.1016/j.polymer.2012.07.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ko YG, Kwon W, Yen HJ, Chang CW, Kim DM, Kim K, Hahm SG, Lee TJ, Liou GS, Ree M. Various Digital Memory Behaviors of Functional Aromatic Polyimides Based on Electron Donor and Acceptor Substituted Triphenylamines. Macromolecules 2012. [DOI: 10.1021/ma300311d] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yong-Gi Ko
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Wonsang Kwon
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Hung-Ju Yen
- Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Cha-Wen Chang
- Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Dong Min Kim
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Kyungtae Kim
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Suk Gyu Hahm
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Taek Joon Lee
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Guey-Sheng Liou
- Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Moonhor Ree
- Department of Chemistry, Division of Advanced Materials Science, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science & Technology (POSTECH), Pohang 790-784, Republic of Korea
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Lee TJ, Ko YG, Yen HJ, Kim K, Kim DM, Kwon W, Hahm SG, Liou GS, Ree M. Programmable digital nonvolatile memory behaviors of donor–acceptor polyimides bearing triphenylamine derivatives: effects of substituents. Polym Chem 2012. [DOI: 10.1039/c2py00617k] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Synthesis and nonvolatile memory characteristics of thermally, dimensionally and chemically stable polyimides. POLYMER 2011. [DOI: 10.1016/j.polymer.2011.03.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Park S, Kim K, Kim DM, Kwon W, Choi J, Ree M. High temperature polyimide containing anthracene moiety and its structure, interface, and nonvolatile memory behavior. ACS APPLIED MATERIALS & INTERFACES 2011; 3:765-773. [PMID: 21338065 DOI: 10.1021/am101125d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A high temperature polyimide bearing anthracene moieties, poly(3,3'-di(9-anthracenemethoxy)-4,4'-biphenylene hexafluoroisopropylidenediphthalimide) (6F-HAB-AM PI) was synthesized. The polymer exhibits excellent thermal stability up to around 410 °C. This polymer is amorphous but orients preferentially in the plane of nanoscale thin films. In device fabrications of its nanoscale thin films with metal top and bottom electrodes, no diffusion of the metal atoms or ions between the polymer and electrodes was found; however, the aluminum bottom electrode had somewhat undergone oxide layer (about 1.2 nm thick) formation at the surface during the post polymer layer formation process, which was confirmed to have no significant influence on the device performance. The polymer thin film exhibited excellent unipolar and bipolar switching behaviors over a very small voltage range, less than ±2 V. Further, the PI films show repeatable writing, reading, and erasing ability with long reliability and high ON/OFF current ratio (up to 10(7)) in air ambient conditions as well as even at temperatures up to 200 °C.
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Affiliation(s)
- Samdae Park
- Division of Advanced Materials Science, Department of Chemistry, Pohang Accelerator Laboratory, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, and Polymer Research Institute, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
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Hahm SG, Jin KS, Park S, Ree M, Kim HS, Kwon SK, Kim YH. The alignment of liquid crystals on the film surfaces of soluble aromatic polyimides bearingt-butylphenyl and trimethylsilylphenyl side groups. Macromol Res 2009. [DOI: 10.1007/bf03218645] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Kim DM, Park S, Lee TJ, Hahm SG, Kim K, Kim JC, Kwon W, Ree M. Programmable permanent data storage characteristics of nanoscale thin films of a thermally stable aromatic polyimide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:11713-11719. [PMID: 19743827 DOI: 10.1021/la901896z] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have synthesized a new thermally and dimensionally stable polyimide, poly(4,4'-amino(4-hydroxyphenyl)diphenylene hexafluoroisopropylidenediphthalimide) (6F-HTPA PI). 6F-HTPA PI is soluble in organic solvents and is thus easily processed with conventional solution coating techniques to produce good quality nanoscale thin films. Devices fabricated with nanoscale thin PI films with thicknesses less than 77 nm exhibit excellent unipolar write-once-read-many-times (WORM) memory behavior with a high ON/OFF current ratio of up to 10(6), a long retention time and low power consumption, less than +/-3.0 V. Furthermore, these WORM characteristics were found to persist even at high temperatures up to 150 degrees C. The WORM memory behavior was found to be governed by trap-limited space-charge limited conduction and local filament formation. The conduction processes are dominated by hole injection. Thus the hydroxytriphenylamine moieties of the PI polymer might play a key role as hole trapping sites in the observed WORM memory behavior. The properties of 6F-HTPA PI make it a promising material for high-density and very stable programmable permanent data storage devices with low power consumption.
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Affiliation(s)
- Dong Min Kim
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, Division of Advanced Materials Science, Polymer Research Institute, and BK School of Molecular Science, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
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Kim K, Park S, Hahm SG, Lee TJ, Kim DM, Kim JC, Kwon W, Ko YG, Ree M. Nonvolatile Unipolar and Bipolar Bistable Memory Characteristics of a High Temperature Polyimide Bearing Diphenylaminobenzylidenylimine Moieties. J Phys Chem B 2009; 113:9143-50. [DOI: 10.1021/jp902660r] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kyungtae Kim
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Samdae Park
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Suk Gyu Hahm
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Taek Joon Lee
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Dong Min Kim
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Jin Chul Kim
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Wonsang Kwon
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Yong-Gi Ko
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
| | - Moonhor Ree
- Department of Chemistry, National Research Laboratory for Polymer Synthesis and Physics, Center for Electro-Photo Behaviors in Advanced Molecular Systems, BK School of Molecular Science, Division of Advanced Materials Science, and Polymer Research Institute, Pohang University of Science & Technology, Pohang 790-784, Republic of Korea
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Lee TJ, Chang CW, Hahm SG, Kim K, Park S, Kim DM, Kim J, Kwon WS, Liou GS, Ree M. Programmable digital memory devices based on nanoscale thin films of a thermally dimensionally stable polyimide. NANOTECHNOLOGY 2009; 20:135204. [PMID: 19420490 DOI: 10.1088/0957-4484/20/13/135204] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have fabricated electrically programmable memory devices with thermally and dimensionally stable poly(N-(N',N'-diphenyl-N'-1,4-phenyl)-N,N-4,4'-diphenylene hexafluoroisopropylidene-diphthalimide) (6F-2TPA PI) films and investigated their switching characteristics and reliability. 6F-2TPA PI films were found to reveal a conductivity of 1.0 x 10(-13)-1.0 x 10(-14) S cm(-1). The 6F-2TPA PI films exhibit versatile memory characteristics that depend on the film thickness. All the PI films are initially present in the OFF state. The PI films with a thickness of >15 to <100 nm exhibit excellent write-once-read-many-times (WORM) (i.e. fuse-type) memory characteristics with and without polarity depending on the thickness. The WORM memory devices are electrically stable, even in air ambient, for a very long time. The devices' ON/OFF current ratio is high, up to 10(10). Therefore, these WORM memory devices can provide an efficient, low-cost means of permanent data storage. On the other hand, the 100 nm thick PI films exhibit excellent dynamic random access memory (DRAM) characteristics with polarity. The ON/OFF current ratio of the DRAM devices is as high as 10(11). The observed electrical switching behaviors were found to be governed by trap-limited space-charge-limited conduction and local filament formation and further dependent on the differences between the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels of the PI film and the work functions of the top and bottom electrodes as well as the PI film thickness. In summary, the excellent memory properties of 6F-2TPA PI make it a promising candidate material for the low-cost mass production of high density and very stable digital nonvolatile WORM and volatile DRAM memory devices.
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Affiliation(s)
- Taek Joon Lee
- Depart. of Chemistry, National Research Lab for Polymer Synthesis and Physics, Center for Integrated Molecular Systems, Polymer Research Institute, and BK School of Molecular Science, Pohang University of Science and Technology, Pohang , Republic of Korea
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Hahm SG, Choi S, Hong SH, Lee TJ, Park S, Kim DM, Kim JC, Kwon W, Kim K, Kim MJ, Kim O, Ree M. Electrically bistable nonvolatile switching devices fabricated with a high performance polyimide bearing diphenylcarbamyl moieties. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b814470m] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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