Luminescence properties and energy transfer processes in Ce3+-Sm3+ co-doped calcium aluminosilicate materials

Ce3+/Sm3+ co-doped calcium aluminosilicate (CA: Ca2Al2SiO7) phosphors were successfully synthesized using the well-known method based on solid-state reaction method at elevated temperature-1280 °C. Key parameters including the structural and luminescent properties of the prepared phosphors are examined in detail via the X-ray diffraction (XRD), a scanning electron microscope (SEM) image, luminescence decay, photoluminescence and photoluminescence excitation spectra. XRD patterns indicated that the obtained phosphors reach a single phase of Ca2Al2SiO7 with tetragonal structure. Fluorescence results of CA:Ce3+ and CA:Sm3+ phosphors show the emission band of Ce3+ overlaps well the strongest excitation peak of Sm3+ lead to the energy transfer (ET) process from Ce3+ to Sm3+ when they are co-doped in CA material. In the co-doped sample CA:Ce3+,Sm3+, the Ce3+ sensitizer enriches the intense red emission of Sm3+ activator regarding the transfer of its part excitation energy to Sm3+ ions. Through analysis of luminescence behaviors, the mechanism of the ET process from Ce3+ to Sm3+ ions in CA phosphors have been determined to be the dipole-dipole interaction by applying the Dexter model. The efficiency (ηET) of energy transfer from Ce3+ ions to Sm3+ ions increase with the increase of Sm3+ concentration. The CIE coordinates of all the prepared samples were also demonstrated under different excitation wavelengths to estimate the emission feature of the prepared phosphors.