The particle size-dependent photoluminescence of nanodiamonds

The intrinsic defects- and impurities-originated photoluminescence from nanodiamond particles of various sizes (5-500 nm) were observed. Luminescence spanning from 500 nm to 800 nm can be excited with 488 nm and 532 nm wavelengths lasers without any high-energy treatment to create the defects/impurities. The luminescence is found to be particle-size and laser-wavelength dependent, suggesting different kinds of defects/impurities predominantly sustain the luminescence from nanodiamonds of different sizes.