Lanthanide-Doped Layered Double Hydroxides Intercalated with Sensitizing Anions: Efficient Energy Transfer between Host and Guest Layers

Layered double hydroxides (LDHs) doped with Tb³⁺ ions in the brucite-like layers were prepared by a simple one-step coprecipitation method at ambient conditions. When 4-biphenylacetate (BPA) anions were intercalated in the interlayer space, a high concentration of Tb³⁺ up to around 19 wt % can be homogeneously incorporated in the octahedral lattice of LDHs. The luminescence study indicated that efficient energy transfer from the excited state of the intercalated BPA guest molecules to Tb³⁺ centers in the host layers takes place. Compared with LDHs without a photosensitizer, Tb³⁺-doped LDHs intercalated with BPA display much enhanced green luminescence from Tb³⁺ ions. Long lifetimes of around 1.3 ms and high quantum yields of 14−22% were obtained. In addition, the emission color of this type of hybrid materials can be tuned from blue to green by varying the amount of Tb³⁺ ions. As the compositions of metal cations and interlayer anions in the LDH structure can be easily varied, the inorganic−organic hybrid system reported here opens great opportunity for developing efficient and functional luminescent materials by simple wet chemical methods.