Divalent tin activator for Nd3+/Yb3+ emission in lanthanum borate glass and its impact on inter-ionic phenomena and thermometry

The co-existence of divalent tin activator and Nd3+/Yb3+ rare earths in the borate glasses were utilized and examined to achieve the effective enhancement of the useful near-infrared emission in the wide spectral region. The UV Sn2+ excitation is extremely relevant for the effectiveness of both (Nd,Yb) near-infrared emission, however, Sn-Nd energy transfer efficiency is particularly prominent. The different advantageous inter-ionic phenomena made it possible to explore the diverse energy transfer routes leading to the population of the relevant ytterbium and neodymium excited states. Consequently, adequate multi-model temperature sensing can be proposed and verified considering single-doped and co-doped borate glass systems. The dissimilar effect of temperature on the complementary Sn2+, Nd3+ and Yb3+ optical transitions was investigated in detail. Employing the temperature-dependent spectra of optically active ions, high values of temperature relative sensitivity (1.3 % K−1) were estimated especially in the physiological range (30 – 75 ⁰C). •Divalent tin activator enhances Near-Infrared Emission of Nd3+/Yb3+ rare earth ions in borate glass•Prominent Sn-Nd-Yb energy transfer routes significantly enhance Yb3+ emissions.•The temperature dependent and independent energy transfer allows for development of multi-model temperature sensing.•High values of temperature relative sensitivity (1.3 % K⁻¹) observed, especially in the physiological range (30–75 ⁰C).