Doping of ZnO inorganic-organic nanohybrids with metal elements

Abstract

We present a general and in-depth study of the effect of dopants in hybrid inorganic/organic ZnO/PAA (polyacrylic acid) nanocomposites. These dopants vary as much by their ionic size, as by their electronic valence and some of them have been used in ZnO due to their known magnetic and/or optical properties. The chemical nature of the dopants controls their ability to incorporate into ZnO crystal lattice. Three concentrations (0.1%, 1% and 5%) of dopants were studied in order to compare the effect of the concentration with the results obtained previously in the literature. Our results confirm in the first place the trend observed in the literature, that increase in dopant concentration leads to quenching of visible luminescence for ZnO nanocrystals obtained by very different processes. However, the degradation of photoluminescence quantum yield (PL QY) is not inevitable in our nanocomposites. At low doping concentration for some dopants with a small or comparable ionic radius than Zn²⁺, PL QY can be maintained or even improved, making it possible to tune the visible emission spectrum between 2.17 eV and 2.46 eV. This opens up the prospect of synthesizing phosphors without rare earth for white LEDs, whose spectrum can be tuned to render warm or cold white light, by a chemical synthesis process with a low environmental impact.