The formation of multiply twinning structure and photoluminescence of well-dispersed nanodiamonds produced by pulsed-laser irradiation

The multiply twinning structure (MTS) of nanodiamonds synthesized by pulsed-laser irradiation was investigated theoretically and experimentally. The thermodynamic calculation shows MTS is more stable than single crystal structure (SCS) in a certain size range and statistical results experimentally accords with the theory. A mechanism on the formation of MTS in nanodiamonds was proposed based on Transmission Electron Microscopy (TEM) observation, in which SCS successively grows into MTS through intermediate states, such as simple twin and triple twin. Furthermore, the dispersive nanodiamonds exhibit strong photoluminescence (PL) after surface passivation.