In order to fully characterize the zinc white artists’ pigment (ZnO), much used since the mid-nineteenth century, three samples collected in the early 20th century were studied using a combination of synchrotron and macroscopic photoluminescence spectroscopy and imaging. An improved microscope setup based on synchrotron microspectroscopy and imaging microscopy was used to study the powders dispersed onto indium foil. The synchrotron setup offered diffraction-limited resolution of 153 nm. The PL spectra of individual grains were measured and the distribution of particles’ emission spectra mapped at the nanoscale. The results revealed that while the samples have apparent homogeneous photoluminescence behavior at the macroscale (bulk), their PL signatures are inhomogenous below 20 μm. At the nanoscale the three powder samples have quite different PL signatures. Different sources, perhaps even different batches, of zinc white might be readily differentiated using this method. We show that this general approach can be used efficiently on a variety of semiconductor pigments.
Voir en ligne : http://dx.doi.org/10.1039/C3AN36874B