Efficient and tunable photoluminescence from Dy3+-doped Cs2NaLuCl6 double perovskites via Sb3+ sensitization

Incorporating rare-earth (RE 3+ ) ions into lead-free halide double perovskites represents a promising strategy for modulating their optical properties through energy transfer mechanisms. In this study, Dy 3+ ions were successfully incorporated into Cs 2 NaLuCl 6 :Sb 3+ double perovskites via a facile hydrothermal method. The synthesized crystals not only exhibit intense blue emission originating from self-trapped excitons (STEs) but also display effective Dy 3+ characteristic emissions, thereby broadening the emission spectrum from the visible to the near-infrared region. The energy transfer from STEs to Dy 3+ is confirmed and extends across various RE 3+ ions. Temperature-dependent photoluminescence spectra reveal insights into the excitation and emission processes, as well as thermal quenching mechanism. Additionally, the characteristic emissions of Dy 3+ demonstrate varied anti-thermal quenching behaviors, indicating the remarkable thermal stability of the synthesized crystals. The thermally coupled sub-levels of Dy 3+ ions are employed to develop optical thermometers with notable sensitivity. Finally, the light-emitting diodes fabricated by encapsulating the optimized samples onto commercial chips highlight the great potential of Dy 3+ -doped Cs 2 NaLuCl 6 :Sb 3+ materials for photoelectric applications.