“…The phenomena of energy transfer in phosphors were extensively observed [16][17][18], especially, those from Ce 3+ to Tb 3+ . However, energy transfer from Eu 2+ to Tb 3+ is rarely seen except in KLn 3 F 10 (Ln = Y, Lu) [19]. In this paper, the energy transfer from Eu 2+ to Tb 3+ in Ca 10 K(PO 4 ) 7 was systematically investigated and a green emitting Ca 10 K(PO 4 ) 7 :Eu 2+ ,Tb 3+ ,K + phosphor was developed for the first time.…”