Photoluminescence (PL) of undoped and Sm-doped TiO2, ZrO2 and HfO2 thin films and fibers was investigated at temperatures ranging from 6 to 300 K. The thin films were grown by the atomic layer deposition (ALD) technique and doped by using the ion implantation method. The fibers were prepared by using the sol-gel method whereas an in-situ doping was used to obtain the required concentration of Sm3+ ions in the films. In undoped as well as doped materials, PL was efficiently excited via band-to-band transitions. The emission of undoped materials was attributed to the radiative recombination of self-trapped excitons (STE). In doped materials, intense emission of Sm3+ was recorded. It is proposed, that there exists a concurrence between the radiative recombination of bound excitonic states and the energy transfer to Sm3+ ions, particularly at lower temperatures.