Optical and electrochemical properties of perovskite type MAlO3 (M = Y, La, Ce) pigments synthesized by a gamma-ray irradiation assisted polyacrylamide gel route

Perovskite type MAlO3 (M = Y, La, Ce) pigments with different phases were successfully prepared by a gamma-ray irradiation assisted polyacrylamide gel route under the same synthesis conditions and their phase purity, surface morphology, and color, optical, photoluminescence and electrochemical properties were characterized by X-ray diffraction (XRD), UV-visible spectroscopy (UV-Vis), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), fluorescence spectroscopy (FS), and electrochemical impedance spectroscopy (EIS). The effects of crystallization temperature and trivalent metal ion M3+ on the physicochemical properties of MAlO3 (M = Y, La, Ce) pigments were systematically investigated. The crystallization temperature of MAlO3 pigments decreases with the increasing ion radius of trivalent metal ions M3+. The synthetic route produced nanosized or porous powders, in addition, no direct relationship was resulted between particle size or energy band gap (Eg) value of MAlO3 pigments with trivalent metal ions M3+. Among all, CeAlO3 and YAlO3 : Ce pigments exhibited excellent photoluminescence properties, in which the emission peaks at 378, 429, 468 and 480 nm with the excitation wavelength at 280 nm and the emission peaks at 369, 413 and 458 nm with the excitation wavelength at 270 nm, respectively. The fluorescence mechanism of the CeAlO3 and YAlO3: Ce pigments were studied based on previous reports and the experimental results. The color and electrochemical properties of MAlO3 pigments change appears to be highly dependent on the trivalent metal ions M3+. Moreover, the results demonstrated that doping Ce3+ ions into YAlO3 precursor solution dropped crystallization temperature and improved phase purity, photoluminescence, and electrochemical properties of YAlO3 pigment.