Rare-earth modified lead titanate ceramics with the nominal formula ${\mathrm{PbRn}}_{1-(3/2)\mathrm{x}}{\mathrm{Ti}}_{\mathrm{x}}{\mathrm{O}}_3$ (PT:R) were prepared by solid-state reaction route and the tailoring effects of rare-earth (Rn) were investigated thoroughly. The X-ray diffraction, photoluminescence, and diffuse reflectance techniques were used as tools to monitor the degree of the structural order in the PT:R system. The higher grain-growth rate induced by the substitution of larger ionic radius ions in Sm-doped shows a more ordered structure corroborated by luminescence band studies. It was also observed that the optical band-gap increases with the decrease of the Rn ionic radii, whereas an opposite behavior was observed for the tetragonality ($c/a$), suggesting the variation of overlapping in the hybridization between the transition 3$d$ and 2$p$ oxygen orbitals in O2 (equatorial) or O1 (axial) in $\mathbf{a}$ or $\mathbf{c}$ direction, respectively. The luminescence of each rare-earth implies the disorder with the decrease of the ionic radii and the presence of a level in the band-gap; the luminescence radiation is linked to oxygen vacancies, which produce the level in the band-gap region. Finally, preliminary X-ray photoelectron spectroscopy was measured in each sample in order to evaluate the site substitution.

$\mathbf{ACKNOWLEDGMENTS}\mathbf{:}$ The authors would like to thank to FAPEMIG and CNPq Brazilian agencies for financial support.