Boosting energy transfer from self-trapped exciton to Er3+ in rare-earth based Cs2NaGdCl6 double perovskites via antimony sensitization for dual-functional applications

The rare-earth based double perovskites (DPs) can effectively solve the poor controllability of lanthanide ions (Ln 3+ ) doping concentrations in traditional double perovskites. In this study, we reshape the UV excitability of Er 3+ by constructing an energy transfer (ET) channel from STE to Er 3+ in the rare-earth based Cs 2 NaGdCl 6 DPs, achieving efficient green emission with the photoluminescence quantum yield (PLQY) of 82.78 %. Excitingly, high-sensitivity temperature measurement within the temperature range of 303–430K is achieved based on the fluorescence intensity ratio (FIR). The maximum relative sensitivities S R (I 526 nm /I 552 nm ) and S R (I 526 nm /I 460 nm ) of Cs 2 NaGd 0.965 Cl 6 : 0.005Sb 3+ , 0.03Er 3+ reach 1.11 % K −1 and 0.90 % K −1 , respectively, indicating that Cs 2 NaGd 0.965 Cl 6 : 0.005Sb 3+ , 0.03Er 3+ is promising optical temperature sensing material. Furthermore, a white light-emitting diode (WLED) device was fabricated using Cs 2 NaGd 0.965 Cl 6 : 0.005Sb 3+ , 0.03Er 3+ and commercial red phosphor CaAlSiN 3 : Eu 2+ with a 365 nm chip, which exhibited a color rendering index (CRI) of 95.1, a correlated color temperature (CCT) of 4989 K, and CIE coordinates of (0.3443, 0.3397). This work broadens the application of rare-earth based Cs 2 NaGdCl 6 DPs.