Preferable forward energy transfer in Tb(C12H8N2)2(NO3)3@Ca0.9Eu0.1MoO4 hierarchical porous composites via the interface

Abstract

Trivalent rare earth Eu³⁺-doped luminescent materials have been used successfully for illumination and displays due to their narrow emission lines and extreme stability. Extending the excitation band to the UV, near UV and blue region via doping lanthanide ions as a sensitizer is highly desired for white LED application. However, the complex redox reaction and forward/backward energy-transfer pathway between the sensitizer ion and Eu³⁺ ion in the same lattice of the phosphor host limits the potential of this strategy. Herein, we present the luminescence properties of hierarchical porous composite materials with the formula Tb(C₁₂H₈N₂)₂(NO₃)₃@Ca_0.9Eu_0.1MoO₄ and report how interfacial energy-transfer enhanced the absorption range of the Eu³⁺-doped material in the UV region. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images illustrated that the obtained Ca_0.9Eu_0.1MoO₄ had a hierarchical porous structure, and the Tb(C₁₂H₈N₂)₂(NO₃)₃ was evenly filled inside the holes or the surface. The photoluminescence and decay data indicated the existence of interfacial forward energy transfer from Tb³⁺ → Eu³⁺. Furthermore, the thermal stability of the composited Tb(C₁₂H₈N₂)₂(NO₃)₃ was improved, indicating the potential of the composite materials for application in UV light-emitting diodes.