Optical enhancement of nonstoichiometry-induced heterojunction in lanthanide doped double perovskite phosphors for WLEDs and scintillation applications

The optical performance of lanthanide-doped inorganic materials, which give promising applications in white light-emitting diode (WLED), optical information storage, X-ray scintillation, etc, greatly depends on the host matrix. Recently, double perovskite structured phosphors have aroused great attention because of their stable and high-efficiency optical properties. More importantly, constructing heterojunctions between distinct phases with matched band structures has been demonstrated to be an effective strategy to improve the optical performance of the corresponding phosphor. Here, we explored the heterojunctional impact on the Dy3+ doped double perovskite Ba2LuNbO6 phosphor by constructing the corresponding matrix with nonstoichiometric ratio of Ba2+ ions. For the appearance of the Dy3+ ions-doped Ba2LuNbO6/LuNbO4 heterojunction, an enhancement of 31.5 times in the photoluminescence intensity and 141.4 times in the radioluminescence intensity is observed compared with that of Ba2LuNbO6: Dy3+ counterpart. The cooperation of heterojunction interface and the oxygen vacancy, which improves the efficiency of electron-hole recombination, is clarified to contribute to the optical enhancement in this work. Moreover, a plausible mechanism is proposed and be demonstrated feasible for the foreign introduction of Eu3+/Sm3+ ions in this perovskite host. This work provides a significant strategy for continually constructing and fabricating efficient inorganic perovskite phosphors for practical applications.