Tunable Emission in Sb³⁺/Eu³⁺ Codoped Rare-Earth-Based Cs₂NaTbCl₆ Double Perovskite and Its LED Applications

Cs₂NaTbCl₆ lead-free dual perovskite (DP) has become one of the alternatives to CsPbBr₃ perovskite quantum dots due to its advantages of nontoxicity, sharpness, and green luminescence. However, the synthesis method and luminescence performance of Cs₂NaTbCl₆ DPs need to be investigated. In this paper, a new synthesis method is used to dissolve metal chloride through water and ethanol, and Sb³⁺-Eu³⁺ codoped Cs₂NaTbCl₆ lead-free double perovskite (DP) is prepared under atmospheric pressure and a low temperature (80 °C). This method not only avoids the use of hydrochloric acid but also has the potential for large-scale production of DPs. Sb³⁺-Eu³⁺ codoped Cs₂NaTbCl₆ DPs prepared by this method has a high PLQY (66.47%), and through energy transfer from Tb³⁺ to Eu³⁺, the luminescence wavelength is adjusted, and multicolor luminescent powder is prepared, which is used to prepare green, yellow, and red light-emitting diodes (LEDs). This shows the application potential in multicolor LEDs.