A New Strategy of Interlayer Doping of Li Ion for Photoluminescence Enhancement of Eu3+ Doped Bismuth Oxychloride Layered Semiconductor

Lattice modification by Li+-doping has been an effective method to manipulate the optical property of lanthanide-doped phosphors, but it lacks an understanding for the highly anisotropic layered host connected by van der Waals forces. Here, based on BiOCl layered crystals prepared by the solid-state method, we systematically studied the doping mechanism of Li+ ions and its effect on the luminescence properties of Eu3+ activators. The experiment and calculation results show that high-concentration Li+ ions can be incorporated into the lattice interlayer of van der Waals force instead of substitutional or interstitial sites. Moreover, Li+ ion dopants greatly decrease the crystalline of BiOCl samples but improve their interlayer electrostatic potential and spontaneous internal electric field (IEF). When the doping concentration increased to 30% mole, the emission intensity of Eu3+ ions under host excitation is enhanced by at least 5 times, accompanying with the prolonged decay time. We show that with interlayer doping of Li+ ion, the local field effect and photocarriers separation role of the enhanced IEF is responsible for the responsible for the special photoluminescence appearance of Eu3+ ion. The results of this paper not only contribute to understand the optical and structural properties of the layered phosphor system but also open up new ideas for the construction and design of efficient photonic materials.