Weak Coupling Strategy to Construct High-Performance\nSm/Tb-Doped Lanthanide Coordination Polymer Luminescent Sensor for\nD<sub>2</sub>O Detection

Accurate\nmeasurement of the purity and content of heavy water is\nof great concern in nuclear energy, the chemical industry, and biomedicine.\nSince the physical and chemical properties of D<sub>2</sub>O and H<sub>2</sub>O are very similar, achieving luminescent detection is challenging.\nDue to the difference in the vibrational frequency of the O–D\nand the O–H bonds, the quenching efficiency of the excited\nstate of Ln<sup>3+</sup> is different, which leads to a significant\ndifference in the optical properties of Ln<sup>3+</sup>. Based on\nthis theory, we composed a weak coupling strategy to strengthen the\nluminescence difference of Ln<sup>3+</sup>. Then, we demonstrated\nthe weak coupling effect and how to improve detection performance\nby analyzing L1-Eu<sub>0.14</sub>Tb<sub>0.86</sub>(C<sub>22</sub>H<sub>20</sub>Eu<sub>0.14</sub>Tb<sub>0.86</sub>N<sub>3</sub>O<sub>10</sub>) and L1-Sm<sub>0.45</sub>Tb<sub>0.55</sub>(C<sub>22</sub>H<sub>20</sub>Sm<sub>0.45</sub>Tb<sub>0.55</sub>N<sub>3</sub>O<sub>10</sub>). The\nstructure and performance of the two sensors were characterized in\ndetail. A series of heavy water detection luminescence sensing experiments\nshow that L1-Sm<sub>0.45</sub>Tb<sub>0.55</sub> and L1-Eu<sub>0.14</sub>Tb<sub>0.86</sub> can not only qualitatively distinguish D<sub>2</sub>O and H<sub>2</sub>O with the naked eye but also quantitatively detect\nany concentration of H<sub>2</sub>O in D<sub>2</sub>O. The prepared\ncomposite films L1-Sm<sub>0.45</sub>Tb<sub>0.55</sub>@PMMA and L1-Eu<sub>0.14</sub>Tb<sub>0.86</sub>@PMMA have practical application value.\nThe application of Sm/Tb-doped lanthanide coordination polymers for\ndetecting the H<sub>2</sub>O content in D<sub>2</sub>O has not been\nreported.