Temperature dependent luminescence properties of Mn2+ ions for site preference of NaCa2GeO4F: Mn2+, Fe3+ phosphor

Optical thermometry offers numerous advantages in the field of temperature detection, such as contactless operation, rapid response time, excellent spatial resolution, and wide detection range. Here, a novel optical thermometry strategy based on distinct temperature-dependent luminescence behaviors of Mn2+ ions at distinct crystal sites of NaCa2GeO4F host matrix is explored. NaCa2GeO4F: Mn2+ phosphor exhibits asymmetry broadband emission for the d-d transitions of Mn2+ ions selectively occupying the cation sites. Accordingly, a tunable color from yellow to red is realized thanks to the modulation of site-occupation preference of Mn2+ ions at distinct sites via additionally incorporating Fe3+ ions, and a distinct temperature-dependent luminescence behavior is endowed for the variation of the local environment of Mn2+ ions, which realizes a satisfied relative temperature sensitivity. Our results indicate that the NaCa2GeO4F: Mn2+, Fe3+ phosphor is a potential candidate for optical thermometry.