Dual-response photoluminescence of rare earth-based halide double perovskites

Sb³⁺-doped rare-earth halide double perovskites (REDPs) have emerged as a novel class of optical and optoelectronic materials for diverse applications because of their enhanced optical properties induced by Sb³⁺ doping. However, the responsive luminescence features of Sb³⁺-doped REDPs, especially dual and multi-responsive luminescence, are rarely discovered. Herein, we show that Sb³⁺-doped Cs₂NaScCl₆ with blue and yellow-green emission centers exhibits both excitation wavelength and temperature-responsive luminescence. Specifically, the dual emission centers of Sb³⁺-doped Cs₂NaScCl₆ exhibit reverse responses to temperature, changing the emission color of Sb³⁺-doped Cs₂NaScCl₆ as the temperature increases from 77 to 440 K. Our studies show that the observed dual-response luminescence should be attributed to the Sb³⁺ doping-enhanced responsive luminescence of pristine Cs₂NaScCl₆. The dual-response luminescence enables the facile luminescence tuning of Sb³⁺-doped Cs₂NaScCl₆ with the assistance of co-doping with Tb³⁺ and Mn²⁺ and gives Sb³⁺-doped Cs₂NaScCl₆ potential for applications including information encryption, anti-counterfeiting, light-emitting diodes, and temperature sensing.