Dual‐Color–Emitting α‐Sr ₂ P ₂ O ₇ :Eu ²⁺ , Mn

ABSTRACT

Undoped and Eu ²⁺ /Mn ²⁺ ‐doped strontium pyrophosphate phosphors (α‐Sr ₂ P ₂ O ₇ and α‐Sr _1.84 P ₂ O ₇ :0.04Eu ²⁺ /0.12Mn ²⁺ ) were successfully prepared using a homogenous co‐precipitation approach for detailed EPR‐PL and crystal‐field effects analysis. XRD confirmed that both samples crystallized in a single‐phase orthorhombic structure, indicating long‐range phase purity and the seamless integration of dopants into the host lattice without structural degradation. To investigate the subtle, localized structural distortions induced by the dopants, EPR spectroscopy was employed as a highly sensitive primary probe. The room temperature EPR spectrum revealed broad Mn ²⁺ resonance lines and distinct low‐field resonances for Eu ²⁺ , highlighting enhanced crystal‐field interactions arising from the relatively low local symmetry at the substituted Sr ²⁺ sites. Under UV excitation, the doped phosphor shows two sharp bands centered at 425 nm (blue) and 560 nm (yellow). Eu ²⁺ acts as a sensitizer for Mn ²⁺ in the phosphor lattice, thereby suggesting a potential energy transfer mechanism from Eu ²⁺ to Mn ²⁺ . This opens a channel to tune the luminescence for possible white light generation through future concentration optimization and decay kinetics studies. These phosphors, with their luminescence and structural characteristics, have potential for color tunable white light–emitting diodes (w‐LEDs) and other solid‐state lighting applications.