White light emitting diodes based on lanthanide ions doped Cs2NaInCl6 double perovskites

Lead-free halide double perovskites are widely used for phosphors converted light emitting diode (pc-LED) devices. However, it remains a challenge to modulate their spectra to meet different application requirements. Herein, Cs2NaInCl6:Sb3+ double perovskite crystals with excellent blue emission of self-trapped excitons (STEs) were prepared and a lanthanide ions (Ln3+) doping strategy was employed to enable multicolor emissions in this system. The emission colors can be continuously adjusted in a wide range by altering the Ln3+ ions doping levels. Especially, white light emissions with tunable correlated color temperature were obtained in Tb3+, Ho3+ ions codoped samples. Outstanding photoluminescence quantum yields of the samples are ascribed to the sensitization effect of Sb3+ ions and the efficient energy-transfer from STEs to Ln3+ ions. LED devices were further fabricated to demonstrate the great application potentials of the prepared phosphors. These findings provide deep insights for the designing of multicolor double perovskite phosphors.