Tailoring of structure, surface, and luminescence properties of nanodiamonds using rapid oxidative treatment

Precise surface functional groups, low sp2 content, and controlled size of agglomerates are the major concerns for using nanodiamonds (NDs) successfully in many biological applications. In this context, we report on the surface modifications of NDs carried out in the temperature range from 450 °C to 750 °C via rapid thermal annealing (RTA). Advantage of RTA is that one can obtain sufficient quantity of final sample. Effects on the ND's surfaces have been scrutinized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, photoluminescence, and time-resolved photoluminescence spectroscopy. FTIR shows red-shift in C=O stretching frequency at 450 °C while at 550 °C and above the surface functional groups are either reduced or completely removed. Raman spectrum shows red-shift and peak broadening of diamond peak with increasing temperature from R.T. to 550 °C. The band characteristic to the graphite at 1585 cm−1 is not observed for oxidative temperatures at 550 °C and 650 °C. Raman measureme...