Virtual Photon Science Seminar
Speaker: Yu Lin, SLAC
Program Description:
Carbon-based nanomaterials have exceptional properties that make them attractive for a variety of technological applications. In this talk, I will discuss 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 (P-T) conditions that yielded diamond were 12 GPa (at ~2000 K) and 900 K (at ~20 GPa), respectively. This represents a significantly reduced transformation barrier compared with diamond synthesis from conventional (hydro)carbon allotropes. At 20 GPa, lower diamondoid-to-diamond conversion occurs rapidly within < 19 ms, forming diamond in a range of sizes ~tens of nm to ~4 mm crystals, depending on the synthesis conditions. Molecular dynamics simulations indicate that once dehydrogenated, the remaining diamondoid carbon cages reconstruct themselves into diamond-like structures at high P-T. The surprisingly low P-T regime necessary to grow diamond from diamondoids is attributed to the similarities in the structure and full sp3 hybridization of diamondoids and bulk diamond. The facile synthesis of diamond suggests a promising use of diamondoids for investigating light emitting defects in diamonds, which is of significant interest in the fields ranging from quantum technologies to biological sciences.
