Using a sol–gel precursor, Na-ion-doped MgO was prepared and applied to alternative current plasma display panels (ac-PDP). The cathodoluminescence spectra showed that the F⁺ center was increased as the concentration of Na⁺ was increased. Numerous pores were found on the printed MgO surface and seemed to give higher memory margin of ac-PDP compared to an electron beam-evaporated MgO film. All doped MgO showed higher secondary electron emission than printed pure MgO, likely owing to the O defect states of MgO. In addition, this result indicated the operational memory margin of the ac-PDP was directly proportional to the grade of surface charging.