A study of strontium aluminates for all optical contactless sensing applications using smartphone interrogation

Abstract

In the present paper we study the spectral and time responses of Eu and Dy doped strontium aluminates and compare the results obtained by means of a standard spectrometer and a smartphone. The advantages of each measurement tool are outlined. It is shown that smartphones equipped with simple transmission diffraction grating can efficiently be used in contactless sensing applications and as measurements tools for the study of the spectral and time dependent responses of phosphors. We also show that smartphones are up to an order of magnitude faster in measuring rise and decay time responses and allow a more detailed analysis of luminescence dynamics compared to spectrometers. A method of duty cycle scanning of the time responses is proposed to study the spectrally and time dependent luminescence structure dynamics which is related to the individual distribution of traps in the phosphors. These smartphone capabilities justify their use as affordable interrogation instruments for time-decay encoded phosphorescent sensors.