Photoluminescence (PL) is cold light emitted from a material after it has been excited with a light source. PL materials exhibit several characteristics that are sensitive to temperature. These thermometric properties are the foundation of phosphor thermometry. By coating a surface with a PL material, the material is brought into thermal equilibrium with the surface. The material can then be interrogated by a well-chosen light source, and its emission observed with either time- or energy-resolved detectors. By comparing some characteristic of the emission to a calibration curve the temperature of the surface can be obtained. This is an elegant approach for non-contact thermometry.

An important thermometric property of a PL material is its decay time, the time necessary for light emission to cease after the excitation source has been removed. Recently europium(III) tetrakis dibenzoylmethide triethylammonium, or EuD₄TEA, was found to have two decay times. Additionally, a competing product, europium (III) tris dibenzolymethide nitrato triethylammonium, or EuD₃NO₃TEA, was discovered. The faster decay time of EuD₄TEA was shown to be identical to the single decay of EuD₃NO₃TEA.

The purpose of this presentation is to present the decay time studies made to discern the cause of the manufacture of the EuD₃NO₃TEA. The environmental conditions in the laboratory where the EuD₃NO₃TEA was made were later found to be suboptimal, with the main source of concern being a high level of humidity. The other difference was the solvent used; the EuD₄TEA had been synthesized with ethanol, whereas the EuD₃NO₃TEA was created with acetone. Thus, the synthesis was followed with acetone as the solvent in a different laboratory. Additionally, several syntheses were made with various mixtures of ethanol and acetone to determine the critical solubility at which the synthesis yields either EuD₄TEA or EuD₃NO₃TEA. This may lead to the ability to tailor the decay time(s) of a PL material.