Heating-induced abnormal increase in Yb3+ excited state lifetime and its potential application in lifetime luminescence nanothermometry

Abstract

The heating-induced unprecedented monotonous increase in Yb³⁺ excited state (²F_5/2) lifetime is found in Nd³⁺/Yb³⁺ codoped fluoride nanoparticles, which is proved to originate from the alleviation of energy migration-mediated surface quenching with elevated temperature. This unique phenomenon is evaluated for thermometric performance in terms of lifetime luminescence thermometry, and the maximum absolute/relative temperature sensitivity (S_a/S_r) reaches as high as 2.68 μs K⁻¹/1.59% K⁻¹ in the biological temperature region, indicating that the studied nanomaterial can offer great potential for lifetime luminescence thermometry in biological areas.