PARAFAC: A tool for the analysis of phosphor mixture luminescence

Parallel factor analysis (PARAFAC) was demonstrated as a tool for the analysis of the time-resolved emission spectra of mixtures of rare-earth phosphors. The time-resolved luminescence spectra of mixtures of europium(III)-doped Gd2O3, Gd2Ti2O7, and GdVO4 powders were measured in the 570-650 nm emission range with time delays varying between 0 and 10 ms. Then, PARAFAC was applied to decompose the time-resolved spectra of the mixtures into the emission spectra and emission decay profiles of the individual phosphors. The second-order advantage of this method was demonstrated by calculating the concentrations of the phosphors in the mixtures after calibrating the PARAFAC model by using samples of known concentrations. This method offered 0.1% detection limit and an average prediction error of 0.034%.