Modification of photoacoustic and photoluminescence spectra of manganese-doped nanocrystals of ZnS due to carboxylic acids

Abstract

Mn-doped ZnS nanocrystals (ZnS:Mn 2+) have been studied from the viewpoint of large luminescence efficiency. Moreover, the photoluminescence (PL) intensity due to Mn 2+ ions is enhanced with the modification by carboxylic acids. Because of the scattering effects there have been few investigations on the optical absorption of ZnS:Mn 2+ nanocrystals. Photoacoustic (PA) technique is useful for scattering materials and the signal intensity shows a peak (∼3.2 eV) owing to Mn 2+ ions absorption. The peak intensities with modification are larger than those without the modification, indicating increase in the role of nonradiative processes. The PL signal intensity shows a peak (∼2.0 eV). The peak intensities with the modification are smaller than that without the modification, indicating the increase of role of nonradiative processes.