Achieving high energy transfer efficiency in Sr6Ca4(PO4)6F2:Ce3+, Mn2+ by regulating the occupation of activator

Series of color tunable Sr6Ca4(PO4)(6)F-2:Ce3+, Mn2+ were achieved. In the way of energy transfer, the activator Mn2+ should get large energy from sensitizer Ce3+ and show high efficiency. However, with increasing Mn2+ concentration the emission intensity of Ce3+ decreases rapidly, the emission intensity of Mn2+ shows unapparent increase. It indicates that there are lots of energy losses in the process of energy transfer from Ce3+ to Mn2+. With the high concentration of Mn2+, the severe concentration quenching effect of Mn2+ occurs in Sr6Ca4(PO4)(6)F-2:Ce3+, Mn2+. In order to reduce the energy loss owing to the concentration quenching effect, Mg2+ ions are introduced into Sr6Ca4(PO4)(6)F-2:Ce3+, Mn-2 to regulate the occupation of Mn2+. Consequently, the distance between Mn2+ increases and the energy loss between Mn2+ is effectively reduced. Therefore the emission intensity of Mn2+ increases greatly, and high energy transfer efficiency of Ce3+-> Mn2+ is achieved.