Optimum Mn-doping, effective tetragonality, and correlated luminescence characteristics of PbTiO3 nanoparticles

The optimum Mn-incorporation and interrelated luminescence characteristics of solid-state derived, PbO-free, nanoscale PbTiO3 systems are reported. X-ray diffraction analysis of the nanosystems predicts a maximum value of tetragonality (similar to 1.06), for a given stoichiometry, namely Mn:Ti = 0.11. Photoluminescence (PL) studies reveal an intense emission peak (lambda(em) similar to 604 nm), which is ascribed to the disordered inorganic phase of lead titanate containing non-bridging oxygen defects. The incorporation of Mn into the lead titanate system has resulted in a more symmetric PL peak owing to its association with Mn2+-related orange emission. Excessive Mn-doping was found to hinder the radiative process significantly owing to the presence of untreated MnO2 phase or the development of a thin MnO2 overlayer on the nanostructure surface.