Dual-color emitting in rare-earth based double perovskites Cs2NaLuCl6: Sb3+, Tb3+ for warm WLED and anti-counterfeiting

Lead-free double perovskites (LFDPs) usually exhibit poor luminescent performance, and doping lanthanide ions (Ln 3+ ) presents a promising solution to solve this problem. However, most Ln 3+ ions face difficulties in incorporating into LFDPs due to the mismatch in radius or valence state. Here, we successfully synthesized rare-earth (RE 3+ ) based Cs 2 NaLuCl 6 (CNLC) LFDPs and achieved efficient green emission through doping Tb 3+ into CNLC. Introducing Sb 3+ improves the absorption efficiency of CNLC: Tb 3+ from 25.1 % to 73.5 % by establishing an energy transfer channel from Sb 3+ to Tb 3+ . Benefiting from the energy transfer, the CNLC: 0.01Sb 3+ , 0.10Tb 3+ phosphor produces blue-green dual emissions, highlighting its potential in white light-emitting diodes (WLEDs). In addition, an anti-counterfeiting pattern composed of CNLC: Sb 3+ , CNLC: Tb 3+ , and CNLC: Sb 3+ , Tb 3+ samples was fabricated, which shows their promising prospect in anti-counterfeiting applications.