Cs2NaScCl6: Sb3+/Er3+ − a dual-emission double perovskite for high-sensitivity optical thermometry

Luminescence-based thermometry offers a viable approach for remote temperature detection, benefiting from its non-invasive nature and superior precision. In the present research, a hydrothermal synthesis route was employed to obtain environmentally friendly Cs 2 NaScCl 6 double perovskite materials co-doped with Sb 3+ /Er 3+ ions. Spectroscopic analysis confirms that Sb 3+ incorporation facilitates the radiative decay of self-trapped excitons, leading to a notable increase in blue luminescence intensity across a wide wavelength range. Energy transfer analysis reveals that Er 3+ co-doping enables efficient STE → Er 3+ energy conversion, populating the 2 H 11/2 and 4 S 3/2 excited states which subsequently radiatively decay to the 4 I 15/2 ground state, yielding dual emission bands. The material exhibits notable temperature-dependent characteristics within the 298–473 K range, as evidenced by tracking the fluorescence intensity ratio (FIR =  I 526 nm / I 551 nm ) of Er 3+ emissions at 526 nm and 551 nm. The achieved maximum relative sensitivity (S R ) reaches 1.40% K −1 with an absolute sensitivity (S A ) of 1.08% K −1 , highlighting its superior capability for high-precision temperature sensing. The findings indicate that the Sb 3+ /Er 3+ co-doped Cs 2 NaScCl 6 double perovskite holds great promise as a material for sensitive optical thermometry, with substantial potential for applications in non-contact temperature sensing.