The influence of Eu3+ concentration on the spectroscopic properties of YAG:Ti, Eu3+ nanocrystalline luminescent thermometer

The influence of Eu3+ co-dopant on the luminescent properties of an yttrium aluminum garnet co-doped with titanium and europium ions (YAG:Ti, Eu) nanocrystals has been investigated. This is a continuation of the search for novel materials suitable for luminescence thermometry using an approach based on inorganic nanocrystals co-doped with transition metal ions and lanthanides. The optical response of Ti3+, Ti4+ and Eu3+ ions present in the examined structures was analyzed in a wide range of temperatures. A model of distribution of energy levels of these ions explaining the observed spectra and their dependence on the Eu concentration was proposed. Moreover, the possibility of energy transfers between these ions and their dependence on the concentration of Eu ions and on the temperature was indicated. On this basis, a model was proposed, allowing for the optimization of the maximum sensitivity and the corresponding temperature.