Multispectral emissive and elongated red emission decay in Sm(DBM)3phen complex modified by SrAl2O4:Eu2+, Dy3+ composite

Abstract

In the present study, we report elongated red emission decay in Sm(DBM)₃phen (SDp) complex stimulated via radiative transfer from a persistent luminescent phosphor SrAl₂O₄:Eu²⁺,Dy³⁺ (SrAl) in the Polyvinyl alcohol (PVA) matrix. The detailed spectroscopic investigations carried out on 405 nm laser excitation reveal the predominating broad emission, centered at 520 nm with a prolonged decay time, while the SDp complex in PVA yields characteristic yellow-red emissions with a decay time of ∼535 μs. The PVA composite yields an amalgam of emissions with modified intensities and change in peak shape due to the lattice effect. We report spectroscopic analysis of the emission spectrum with varying concentrations, layer stacking, lattice effect, etc. The lattice leads the emission peak broadening, facilitating improved interaction between the SDp complex and SrAl phosphor. The radiative decay analysis of red emission for transition ⁴G_5/2→⁶H_9/2 (Sm³⁺ ion) reveals that in PVA, it decays slower (∼535μs) than the pure complex (∼260μs). Further, red emission was present even after cessation of excitation due to the elongated radiative decay (∼3.5ms) in the presence of SrAl phosphor in PVA, indicating efficient radiative transfer (transfer rate of ∼1580 s^-1) from the phosphor to Sm(DBM)₃phen complex. Detailed photophysics and CIE coordinate calculations were presented.