Absolute luminescence quantum yield for nanosized carbon particles in water as a function of excitation wavelength

The absolute luminescence quantum yield Q as a function of excitation wavelength lambda(ex) in a wide spectral range 270-470 nm was measured for the first time for the group of carbon nanoparticles dispersed in water: carbon dots (CD), detonation nanodiamonds (DND), as well as detonation nanodiamonds decorated with carbon dots (CD-DND). The luminescence quantum yield for DND increased after functionalization; the CD-decorated DND demonstrated significantly higher Q values in the UV region of excitation. We found that the quantum yield for CD luminescence is 4-8 times higher than that for CD-DND luminescence, and 20 times higher than that for DND luminescence. Roughly three spectral regions can be distinguished within the Q(lambda(ex)): below 330 nm, 330-390 nmand 390-470 nm. Conclusions are drawn about the number of chromophores of the studied nanoparticles and transfer of photoexcitation energy in the systems under consideration. (c) 2019 Elsevier B.V. All rights reserved.