Synthesis and luminescent properties of Mn-doped alpha-tricalcium phosphate

In this work, a series of Mn²⁺-doped α-tricalcium phosphate (α-TCP) powders was synthesized by wet co-precipitation method followed by high-temperature annealing and thermal quenching. It was shown that Mn²⁺-doped α-TCP polymorph can be successfully synthesized with a doping level up to 1 mol%. All Mn-doped samples exhibited a broadband emission in the range from 525 to 825 nm with a maximum centered at around 630 nm. The highest emission intensity was observed for the sample with the highest content of Mn. The crystal structure and purity were evaluated by powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and electron paramagnetic resonance (EPR) spectroscopies. Scanning electron microscopy (SEM) was used to investigate the morphological features of the synthesized products. Optical properties were investigated by means of photoluminescence measurements. Excitation spectra, emission spectra and decay curves of the samples were studied. Temperature-dependent photoluminescence measurements were performed as well.