The local structure in heavily boron-doped diamond and the effect this has on its electrochemical properties
| Autor: | Tomokazu Yamamoto, Satoru Yoshioka, Tadakatsu Ohkubo, Takeshi Watanabe, Hossein Sepehri-Amin, Yasuaki Einaga, Syo Matsumura |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Electron energy loss spectroscopy Analytical chemistry chemistry.chemical_element Diamond 02 engineering and technology General Chemistry engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry engineering General Materials Science Grain boundary Crystallite Graphite Diamond cubic 0210 nano-technology Boron Carbon |
| Zdroj: | Carbon. 137:333-342 |
| ISSN: | 0008-6223 |
| DOI: | 10.1016/j.carbon.2018.05.026 |
| Popis: | Transmission electron microscopy (TEM) coupled with electron energy loss spectroscopy (EELS), and first principles calculations of EEL spectra were utilized to elucidate the relationship between the microscopic structure and the electrochemical properties of heavily boron-doped diamond (h-BDD). The electrochemical properties of h-BDD containing 1 at.% and 3 at.% boron are very different. TEM observations showed that 1 at.% h-BDD consists of small densely packed diamond crystallites, while 3 at.% h-BDD contains small voids and a graphite phase partly along the grain boundaries. The EEL spectrum of the grain interior in 1 at.% h-BDD and comparison of this with a theoretical spectrum shows that the boron atoms are mostly dispersed as single isolated substitutional atoms on diamond lattice sites in the grain interior and that only a small amount of sp2-bonded carbon is present. In contrast, in the grain interior of 3 at.% h-BDD, the boron atoms are mostly associated with nearest neighbor boron pairs, and consequently sp2-bonded carbon is formed. Thus, the local structure has a significant effect on the amount of sp2-bonded carbon. The quite different electrochemical properties of the samples are ascribed to the amount of sp2-bonding arising from the different local structures. |
| Databáze: | OpenAIRE |
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