Multipath luminescent thermometry in Cs3GdGe3O9:Yb3+, Er3+ phosphor

Nowadays, luminescent thermometry appeals the eyes of researchers more and more on account of the unique merits including non-invasive, fast response and relatively high sensitivity. However, most of reported up -conversion optical thermometric materials based on fluorescence intensity ratio (FIR) from thermal couple en-ergy levels (TCELs) usually suffer from the overlap of two luminescence signals, leading to the deviation of the temperature readout. Herein, Cs3GdGe3O9:Yb3+,Er3+ phosphors were successfully synthesized. Multiple sharp peaks from green and red luminescence of Er3+ are observed. The emission signals even from the TCELs are well separated, enabling the accuracy of temperature detection to some extent. With the aid of the different thermo-responses of luminescence centered at 534, 559, 660 nm and their splitting peaks of Er3+, multi-mode optical thermometric techniques based on fluorescence decay time (4S3/2), FIR from TCELs, non-TCELs and their sub -energy levels in Cs3GdGe3O9:Yb3+,Er3+ upon single-beam light stimulation were designed. The resultant sam-ple reveals excellent signal discernibility, eminent relative sensitivities, outstanding reversibility and glorious thermal resolution. Such results infer that Cs3GdGe3O9:Yb3+,Er3+ phosphors have the promising prospect in temperature monitoring fields.