Tunable emission In Cs2NaGdCl6: Sb3+, Sm3+ double perovskite for cool white LEDs and anti-counterfeiting applications

Lead-free halide perovskites are highly appealing for optoelectronic applications due to their non-toxic nature and exceptional optical properties. In this study, we report the co-doping of Sb 3+ and Sm 3+ in the rare-earth-based double perovskite Cs 2 NaGdCl 6 . The incorporation of Sb 3+ ions effectively tunes the electronic structure, achieving a photoluminescence quantum yield (PLQY) of up to 87.9 %. The Sb 3+ /Sm 3+ -co-doped Cs 2 NaGdCl 6 exhibits excitation wavelength-dependent emission characteristics, transitioning from blue emission under 260 nm excitation to white emission under 365 nm excitation. Furthermore, the Sb 3+ /Sm 3+ -co-doped Cs 2 NaGdCl 6 material demonstrates advanced multifunctional applications in light-emitting diode (LED) lighting and fluorescence anti-counterfeiting technologies. These findings hold significant implications for the utilization of rare-earth-based double perovskites in optoelectronic devices.