Weak Coupling Strategy to Construct High-Performance Sm/Tb-Doped Lanthanide Coordination Polymer Luminescent Sensor for D2O Detection

Accurate measurement of the purity and content of heavy water is of great concern in nuclear energy, the chemical industry, and biomedicine. Since the physical and chemical properties of D₂O and H₂O are very similar, achieving luminescent detection is challenging. Due to the difference in the vibrational frequency of the O-D and the O-H bonds, the quenching efficiency of the excited state of Ln³⁺ is different, which leads to a significant difference in the optical properties of Ln³⁺. Based on this theory, we composed a weak coupling strategy to strengthen the luminescence difference of Ln³⁺. Then, we demonstrated the weak coupling effect and how to improve detection performance by analyzing L1-Eu_0.14Tb_0.86(C₂₂H₂₀Eu_0.14Tb_0.86N₃O₁₀) and L1-Sm_0.45Tb_0.55(C₂₂H₂₀Sm_0.45Tb_0.55N₃O₁₀). The structure and performance of the two sensors were characterized in detail. A series of heavy water detection luminescence sensing experiments show that L1-Sm_0.45Tb_0.55 and L1-Eu_0.14Tb_0.86 can not only qualitatively distinguish D₂O and H₂O with the naked eye but also quantitatively detect any concentration of H₂O in D₂O. The prepared composite films L1-Sm_0.45Tb_0.55@PMMA and L1-Eu_0.14Tb_0.86@PMMA have practical application value. The application of Sm/Tb-doped lanthanide coordination polymers for detecting the H₂O content in D₂O has not been reported.