Photoluminescence and thermal behavior of Pb2+-Doped CaMgB2O5: A candidate phosphor for UV-LED technology

Abstract

Phosphors with the composition Ca_1-xPb_xMgB₂O₅ (0.0025 ≤ x ≤ 0.03) were synthesized at 900 °C for 6 h in an air atmosphere via a solution combustion method. The phase composition of all synthesized borates was confirmed by powder X-ray diffraction (XRD) and the diffraction peaks matched with the standard card of CaMgB₂O₅ (JCPDS–0 73–0618). The bond structure and morphological characteristics of CaMgB₂O₅ were examined using Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. Photoluminescence properties were investigated at room temperature, revealing excitation and emission bands at 271 nm and 341 nm, respectively, for CaMgB₂O₅:Pb²⁺. The optimal Pb²⁺ concentration for maximum emission intensity was determined as 0.01 mol. A large Stokes shift of 7575 cm⁻¹ was observed, indicating strong electron–phonon coupling and reduced reabsorption losses. Thermal analysis (TGA/DSC) demonstrated high thermal stability above 900 °C. The combination of strong near-UV emission, thermal robustness, and the use of waste-derived Pb²⁺ sources makes this phosphor a promising candidate for UV-LEDs, germicidal lighting, photochemical excitation, and other solid-state lighting applications. This study introduces a novel, sustainable UV-emitting borate material to the literature with potential for high-performance optoelectronic devices.