Blue-green CaSc2O4:Tb3+ phosphors have been prepared by solid-state reaction. Under 254 or 276 nm light excitation, both blue and green emissions are observed, which are attributed to the characteristic 4f-4f transitions (D-5(3,4)-F-7(J), J = 6, 5, 4, 3) of Tb3+. The cross-relaxation from D-5(3) to D-5(4) states are investigated by spectroscopic and dynamic measurements. The luminescent color of CaSc2O4:Tb3+ can be tuned from blue to green by manipulating the cross-relaxation. Moreover, efficient white light is generated for fluorescence lamps by blending the blue-green CaSc2O4:Tb3+ with a red CaSc2O4:Eu3+ phosphor. (c) 2009 The Electrochemical Society. [DOI: 10.1149/1.3060382] All rights reserved.