VUV/Vis Photoluminescence, Site Occupancy, and Thermal-Resistance Properties of K 4 SrSi 3 O 9 :Ce 3 .

A series of Ce3+ -activated K4 SrSi3 O9 materials emitting bright blue light under near-UV excitation was obtained by a facile solid-state reaction. The luminescence of Ce3+ -doped K4 SrSi3 O9 shows excellent thermal stability in a large temperature range. The detailed temperature/concentration-dependent luminescent properties of Ce3+ confirm that there are two different Ce3+ sites in K4 SrSi3 O9 :Ce3+ , and energy transfer from the high-energy Ce(1)3+ sites to the low-energy Ce(2)3+ sites was demonstrated to occur by electric dipole-dipole interaction. The maximum photoluminescence quantum yield of Ce3+ -doped K4 SrSi3 O9 can reach 56 %, and a UV-excited white LED device with low correlated color temperature (CCT=4617 K) and high color-rendering index (Ra =80) was fabricated with K4 SrSi3 O9 :Ce3+ .