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Two-dimensional layered hybrid organic–inorganic bronze (HOIB) materials are a new class of mixed-valence hybrid metal-oxides that demonstrate great potential as advanced functional materials for next-generation electronics. Recently, new hybrid vanadium bronze materials, (EV)V8O20 and (MV)V8O20, EV = ethyl viologen and MV = methyl viologen, have been introduced, with EV having ≈3 orders of magnitude higher electrical conductivity than the MV system. Given their stoichiometrically similar inorganic V–O layers and close reduction potentials, the observed significant difference in electrical conductivities is puzzling. Here, through accurate first-principles electronic structure calculations coupled with MACE machine learning molecular dynamics (MD) simulations validated by accurate ab initio MD data, we provide mechanistic molecular-level insights into dominant charge transport and electrical conductivity pathways in these materials. Our detailed structural and electronic properties data identify factors contributing to this significant difference in the electrical conductivity of these materials. Our findings in this work offer clues and provide valuable insights into improving the electrical conductivity of hybrid bronze and similar materials, suggesting new ways to guide the design of next-generation materials with enhanced properties for electronic and energy conversion applications.
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Manipulating the electrical properties of conductive substoichiometric titanium oxides
Conducting metal oxides offer many advantages for novel electronics applications, including sensors, fuel cells, piezoelectric devices, and microelectronic circuits, due to their conductivity, hardness, and chemically inert surfaces. In particular, their high electrical conductivity and mechanical properties make these materials suitable for microelectromechanical and nanoelectromechanical system (MEMS/NEMS) devices. NEMS switches have great potential for next-generation electronic computing associated with scalability to small dimensions, low power consumption, and (relatively) high speed. Oxygen-deficient Ti oxides with ordered planes of vacancies (TinO2n−1, Magn´eli phases) are good candidates for NEMS applications because of their metallic conductivity, environmental resistance, and low cost, as compared with other conductive oxides like RuO2. Although Ti sub-oxides have been produced in crystalline form, various synthesis methods may also produce amorphous material. In this work, we focus on the structural and electrical transport properties of several Ti sub-oxides. In particular, we examine the effects of temperature, transition-metal dopants, and amorphization on these structural and electronic properties and the potential applicability of Magn´eli phase Ti sub-oxides for NEMS switch applications.
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- Award ID(s):
- 1854702
- PAR ID:
- 10532304
- Publisher / Repository:
- American Physical Society
- Date Published:
- Journal Name:
- Physical Review B
- Volume:
- 109
- Issue:
- 6
- ISSN:
- 2469-9950
- Subject(s) / Keyword(s):
- DFT materials modeling titanium suboxides conductive oxides NEMS MEMS
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1103/PhysRevB.109.064106
