Effect of Na+ co-dopant and activator concentration on luminescent properties of CaGa4O7:Eu3+

► Undoped CaGa4O7 upon 255 nm excitation exhibit a bluish white emission followed by an afterglow lasting for 10-20 s. ► Eu3+ doped CaGa4O7 exhibits intense orange-red emission when excited at 395 nm. ► In CaGa4O7:Eu3+ sample the active ions occupy more than one symmetry center. ► Co-doping with Na+ ions leads to a remarkable reduction of number of Eu3+ sites and strongly enhanced luminescence.