Preparation and characterization of a new orange-red phosphor Ba2LaTaO6:Eu3+ with abnormal thermal quenching

Abstract

Herein, double-perovskite Ba2LaTaO6 Eu-doped orange-red phosphors were successfully synthesized using a high-temperature solid-phase method. The phosphor phase purity was investigated using X-ray diffraction and microscopic morphology analyses. Their luminescence properties were investigated using absorption, emission, excitation, and temperature-dependent spectra. The transition mechanism mainly involves a magnetic–dipole transition with an energy transfer mode featuring multipole–multipole interactions, and concentration quenching is achieved via dipole–dipole interactions. In addition, the intensity of the temperature-dependent spectrum increases abnormally between 298 and 373 K, with the luminous intensity at 373 K increasing to 110% of that observed at room temperature. This phenomenon can be attributed to lattice defects in Ba2LaTaO6:Eu3+, and the phosphor luminous intensity at 473 K remains at 80.62% of that at room temperature. In addition, white-light-emitting diode devices based on this novel Ba2LaTaO6:0.35Eu3+ phosphor were fabricated to evaluate the potential applications of the as-prepared phosphor.