Differentiation of photon generation in single- and bi- ligand europium complexes doped poly methyl methacrylate

Eu(DBM)₃ and Eu(DBM)₃Phen were introduced into poly methyl methacrylate (PMMA) in comparative, and the differential luminescence behaviors were revealed under ultraviolet (UV) radiation. The comparison of excitation behavior between Eu(DBM)₃ and Eu(DBM)₃Phen doped PMMAs indicates that the introduction of Phen ligand largely enhances the excitation intensity of europium in the entire UV region. The total quantum yield of Eu(DBM)₃Phen doped PMMA was derived to be (9.34 ± 0.14)%, and it is about 8 times higher than that of the Eu(DBM)₃ doped PMMA under 373 nm UVA light emitting diode (UVA-LED) excitation, which confirms the effective utilization of UVA radiation by introducing Phen ligand. Similar results on absolute spectral parameters of the bi-ligand under the excitation of 308 nm UVB light emitting diode (UVB-LED) further support the availability for photon conversion. The brilliant red fluorescence of Eu(DBM)₃Phen doped PMMA under direct sunlight demonstrates the contribution of Phen to modify the solar spectrum and enhance the UV radiation conversion efficiency, which make the Eu(DBM)₃Phen doped PMMA an attractive UV radiation conversion layer for solar cell.