Visible emission studies of melt-grown Dy-doped CsPbCl₃ and KPb₂Cl₅ crystals

We report results of the optical properties of Dy-doped CsPbCl3 and KPb2Cl5 bulk crystals for potential applications in yellow solid-state laser development. The crystals were synthesized from purified starting materials and melt-grown by vertical Bridgman technique. Optical transmission measurements revealed characteristic absorption bands from intra-4f transitions of Dy3+ ions. Direct optical excitation at 455 nm (6H15/2 → 4I15/2) resulted in dominant yellow emission bands at ∼575 nm from the 4F9/2 excited state of Dy3+ ions. In addition, both crystals exhibited weaker emission lines in the blue (∼483 nm) and red (∼670 nm) regions. The peak emission-cross sections for the yellow transition (4F9/2 → 6H13/2) were determined to be ∼0.22 × 10−20 cm2 for Dy: CsPbCl3 (λpeak = 576.5 nm) and ∼0.59 × 10−20 cm2 for Dy: KPb2Cl5 (λpeak = 574.5 nm). The spectral properties and decay dynamics of the 4F9/2 excited state were evaluated within the Judd-Ofelt theory to predict total radiative decay rates, branching ratios, and emission quantum efficiencies.