In this work, Y2O3:Eu3+ thin-film phosphors were prepared by an electrodeposition method. The effect of Li+ ions on the photoluminescence properties of Y2O3:Eu3+ thin-film phosphor was studied in detail. The addition of Li+ ions could improve the photoluminescence intensity by around 3.5 times. The greatly improved photoluminescence intensity may be caused by different factors. The most likely factors are the improved crystallinity and the increased optical volume caused by the flux effect of Li+ ions. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3489074] All rights reserved.