Observation of the "Red Edge" Effect in the Luminescence of Water Suspensions of Detonation Nanodiamonds

Abstract

The variations in the luminescence spectra of detonation nanodiamond (DND) with probe light wavelength are studied and these dependences are compared for water suspensions of DND and graphene oxide (GO). It is found that changing the laser excitation wavelength from 405 to 532 nm shifts the broad-band luminescence peaks of DND and GO from 530 to 615 nm and from 490 to 580 nm. The observed dependences are explained by the luminescence ″red edge″ effect, which shows up when the electrostatic interaction (solvation) times of a luminophore with a polar solvent are comparable to the luminescence lifetime. These data confirm the common origin of luminescence in nanodiamonds and oxidized graphene nanoclusters.