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Tahara K, Terashita N, Tokunaga K, Yabumoto S, Kikuchi JI, Ozawa Y, Abe M. Zwitterionic Mixed Valence: Internalizing Counteranions into a Biferrocenium Framework toward Molecular Expression of Half-Cells in Quantum Cellular Automata. Chemistry 2019; 25:13728-13738. [PMID: 31376186 DOI: 10.1002/chem.201902840] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/26/2019] [Indexed: 01/26/2023]
Abstract
Realization of molecular quantum cellular automata (QCA), a promising architecture for molecular computing through current-free processes, requires improved understanding and application of mixed-valence (MV) molecules. In this report, we present an electrostatic approach to creating MV subspecies through internalizing opposite charges in close proximity to MV ionic moieties. This approach is demonstrated by unsymmetrically attaching a charge-responsive boron substituent to a well-known organometallic MV complex, biferrocenium. Guest anions (CN- and F- ) bind to the Lewis acidic boron center, leading to unusual blue-shifts of the intervalence charge-transfer (IVCT) bands. To the best of our knowledge, this is the first reported example of a zwitterionic MV series in which the degree of positive charge delocalization can be varied by changing the bound anions, and serves to clarify the interplay between IVCT parameters. The key underlying factor is the variable zero-level energy difference in the MV states. This work provides new insight into imbuing MV molecules with external charge-responsiveness, a prerequisite of molecular QCA techniques.
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Affiliation(s)
- Keishiro Tahara
- Department of Material Science, Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Ako, Hyogo, 678-1297, Japan
| | - Nazuna Terashita
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
| | - Ken Tokunaga
- Division of Liberal Arts, Centre for Promotion of Higher Education, Kogakuin University, 2665-1, Nakano, Hachioji, Tokyo, 192-0015, Japan
| | - Shiomi Yabumoto
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
| | - Jun-Ichi Kikuchi
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
| | - Yoshiki Ozawa
- Department of Material Science, Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Ako, Hyogo, 678-1297, Japan
| | - Masaaki Abe
- Department of Material Science, Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Ako, Hyogo, 678-1297, Japan
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Rahimi E, Reimers JR. Molecular quantum cellular automata cell design trade-offs: latching vs. power dissipation. Phys Chem Chem Phys 2018; 20:17881-17888. [PMID: 29924110 DOI: 10.1039/c8cp02886a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The use of molecules to enact quantum cellular automata (QCA) cells has been proposed as a new way for performing electronic logic operations at sub-nm dimensions. A key question that arises concerns whether chemical or physical processes are to be exploited. The use of chemical reactions allows the state of a switch element to be latched in molecular form, making the output of a cell independent of its inputs, but costs energy to do the reaction. Alternatively, if purely electronic polarization is manipulated then no internal latching occurs, but no power is dissipated provided the fields from the inputs change slowly compared to the molecular response times. How these scenarios pan out is discussed by considering calculated properties of the 1,4-diallylbutane cation, a species often used as a paradigm for molecular electronic switching. Utilized are results from different calculation approaches that depict the ion either as a charge-localized mixed-valence compound functioning as a bistable switch, or else as an extremely polarizable molecule with a delocalized electronic structure. Practical schemes for using molecular cells in QCA and other devices emerge.
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Affiliation(s)
- Ehsan Rahimi
- Faculty of Electrical and Robotic Engineering, Shahrood University of Technology, Shahrood, Iran.
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Shlykov AI, Baimuratov AS, Baranov AV, Fedorov AV, Rukhlenko ID. Optically active quantum-dot molecules. OPTICS EXPRESS 2017; 25:3811-3825. [PMID: 28241593 DOI: 10.1364/oe.25.003811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chiral molecules made of coupled achiral semiconductor nanocrystals, also known as quantum dots, show great promise for photonic applications owing to their prospective uses as configurable building blocks for optically active structures, materials, and devices. Here we present a simple model of optically active quantum-dot molecules, in which each of the quantum dots is assigned a dipole moment associated with the fundamental interband transition between the size-quantized states of its confined charge carriers. This model is used to analytically calculate the rotatory strengths of optical transitions occurring upon the excitation of chiral dimers, trimers, and tetramers of general configurations. The rotatory strengths of such quantum-dot molecules are found to exceed the typical rotatory strengths of chiral molecules by five to six orders of magnitude. We also study how the optical activity of quantum-dot molecules shows up in their circular dichroism spectra when the energy gap between the molecular states is much smaller than the states' lifetime, and maximize the strengths of the circular dichroism peaks by optimizing orientations of the quantum dots in the molecules. Our analytical results provide clear design guidelines for quantum-dot molecules and can prove useful in engineering optically active quantum-dot supercrystals and photonic devices.
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Tsukerblat B, Palii A, Clemente-Juan JM, Coronado E. Mixed-valence molecular four-dot unit for quantum cellular automata: Vibronic self-trapping and cell-cell response. J Chem Phys 2015; 143:134307. [DOI: 10.1063/1.4932106] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
| | - Andrew Palii
- Institute of Applied Physics, Academy of Sciences of Moldova, Kishinev, Moldova
| | | | - Eugenio Coronado
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Paterna, Spain
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Santana Bonilla A, Gutierrez R, Medrano Sandonas L, Nozaki D, Bramanti AP, Cuniberti G. Structural distortions in molecular-based quantum cellular automata: a minimal model based study. Phys Chem Chem Phys 2014; 16:17777-85. [DOI: 10.1039/c4cp02458c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular-based quantum cellular automata (m-QCA) offer a novel alternative in which binary information can be encoded in the molecular charge configuration of a cell and propagated via nearest-neighbor Coulombic cell–cell interactions. Structural distortions of the cells may have however a sensitive influence on the m-QCA response and thus, potentially alter its functionality.
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Affiliation(s)
- Alejandro Santana Bonilla
- Institute for Materials Science and Max Bergmann Center of Biomaterials
- Dresden University of Technology
- 01062 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems
- 01187 Dresden, Germany
| | - Rafael Gutierrez
- Institute for Materials Science and Max Bergmann Center of Biomaterials
- Dresden University of Technology
- 01062 Dresden, Germany
| | - Leonardo Medrano Sandonas
- Institute for Materials Science and Max Bergmann Center of Biomaterials
- Dresden University of Technology
- 01062 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems
- 01187 Dresden, Germany
| | - Daijiro Nozaki
- Institute for Materials Science and Max Bergmann Center of Biomaterials
- Dresden University of Technology
- 01062 Dresden, Germany
| | | | - Gianaurelio Cuniberti
- Institute for Materials Science and Max Bergmann Center of Biomaterials
- Dresden University of Technology
- 01062 Dresden, Germany
- Center for Advancing Electronics Dresden
- Dresden University of Technology
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