Sensing with phosphor-doped PDMS

Thermometry with thermographic phosphors usually involves superficial application of a thin coating to the surface of interest. In contrast, the subject here concerns a thicker luminescent target consisting of a flexible phosphor-doped polymer, from the polydimethylsiloxane (PDMS) family. The purpose is to produce a flexible attachable/detachable material which can be used for temperature measurement of the underlying surface it contacts. PDMS samples loaded with 1, 5, 15, and 50% of the phosphor La₂O₂S:Eu were fabricated and tested. For all doping levels, detectable and useful fluorescence signals were readily attained for 365 and 405 nm incident excitation. The PDMS host appeared not to affect the spectral properties of the incorporated phosphor. Additional characterization of optical, thermal and mechanical properties (stress/ strain behavior and temperature dependent compression response) as a function of dopant concentration described here validate this as a temperature sensing material.