The fluorescence, phosphorescence and thermoluminescence properties of Eu3+ and Gd3+ single-doped and co-doped Ca2SnO4 phosphors sintered in air and in oxygen-deficient atmosphere (vacuum) were investigated. The red phosphorescence of phosphor Ca2SnO4: Gd3+, Eu3+ sintered in vacuum atmosphere can last for over 6480 sec at a recognizable intensity level, whereas the red phosphorescence of air-sintered phosphor Ca2SnO4: Eu3+ can only persist for 1080 sec. And the blue phosphorescence of phosphor Ca2SnO4: Gd3+ sintered in vacuum atmosphere can last for over 10200 sec, but the phosphorescence of air-sintered phosphor Ca2SnO4: Gd3+ can only persist for 5820 sec. A new efficient persistent energy transfer system from the self-trapped excitation of Gd3+ to Eu3+ was suggested based on the fact of obvious overlap between the emission band of Ca2SnO4: Gd3+ and the excitation band of Ca2SnO4: Eu3+. The oxygen vacancies were beneficial to the afterglow property of RE3+ (RE = Gd, Eu) doped Ca2SnO4. The results of this study suggested that the [2RF(Ca)(center dot) - 2V ''(Ca) - V-O(center dot center dot)] defects clusters were responsible for the afterglow of vacuum-sintered Ca2SnO4: RE3+. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.062112jes] All rights reserved.