A study on the near-infrared luminescent properties of xerogel materials doped with dysprosium complexes

A series of dysprosium complex doped xerogels with the same first ligand (acac = acetylacetone) and different neutral ligands were synthesized in situ via a sol-gel process. The Fourier transform infrared (FTIR) spectra, diffuse reflectance (DR) spectra, and near-infrared (NIR) luminescent properties of dysprosium complexes and dysprosium complex doped xerogels are described in detail. The results reveal that the dysprosium complex is successfully synthesized in situ in the corresponding xerogel. Excitation at the maximum absorption wavelength of the ligands resulted in the characteristic NIR luminescence of the Dy3+ ion, which contributes to the energy transfer from the ligands to the central Dy3+ ion in both the dysprosium complexes and xerogels via an antenna effect. The NIR luminescent properties of the dysprosium complexes and xerogels were compared, respectively. The evidence showed that the neutral ligand triphenyl phosphine oxide (TPPO) could increase the emission intensity of the dysprosium complex while 1,10-phenanthroline (phen) gave the negative effect. In addition, the coordinated water molecules affect the emission intensity of the dysprosium complex doped xerogel without the neutral ligand.