Facile diamond synthesis from lower diamondoids.

Park, Sulgiye; Abate, Iwnetim I; Liu, Jin; Wang, Chenxu; Dahl, Jeremy E P; Carlson, Robert M K; Yang, Liuxiang; Prakapenka, Vitali B et al. · Sci Adv · 2020

basic_science · Level V

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Abstract

Carbon-based nanomaterials have exceptional properties that make them attractive for a variety of technological applications. Here, we report on the use of diamondoids (diamond-like, saturated hydrocarbons) as promising precursors for laser-induced high-pressure, high-temperature diamond synthesis. The lowest pressure and temperature (<i>P-T</i>) conditions that yielded diamond were 12 GPa (at ~2000 K) and 900 K (at ~20 GPa), respectively. This represents a substantially reduced transformation barrier compared with diamond synthesis from conventional (hydro)carbon allotropes, owing to the similarities in the structure and full sp<sup>3</sup> hybridization of diamondoids and bulk diamond. At 20 GPa, diamondoid-to-diamond conversion occurs rapidly within <19 μs. Molecular dynamics simulations indicate that once dehydrogenated, the remaining diamondoid carbon cages reconstruct themselves into diamond-like structures at high <i>P-T</i>. This study is the first successful mapping of the <i>P-T</i> conditions and onset timing of the diamondoid-to-diamond conversion and elucidates the physical and chemical factors that facilitate diamond synthesis.