Photoluminescent Tetragonal Tb-doped Pb ₂ P ₂ O ₇

In this study, we report the synthesis and characterization of a novel tetragonal polymorph of Tb-doped Pb2P2O7. Single-crystal X-ray diffraction confirms the stabilization of the P41 and P43 enantiomorphs at room temperature due to the incorporation of Tb3+ ions. Optical investigations reveal green photoluminescence from the characteristic 5D4 → 7Fj (j = 1–5) transitions of Tb3+, with each emission split due to the crystal field effect, indicating the presence of Tb3+ in multiple coordination environments. The power dependence of the PL intensity follows a linear power-law behavior, suggesting a one-photon excitation process. Temperature-dependent PL measurements show an initial increase in intensity up to 125 °C, attributed to energy transfer from structural defects, followed by thermal quenching above this temperature. Structural stability at elevated temperatures is confirmed via high-temperature X-ray diffraction, showing no phase transitions before melting at approximately 800 °C. These findings highlight the potential of tetragonal Tb-doped Pb2P2O7 as a new class of photoluminescent material.