VUV/Vis Photoluminescence, Site Occupancy, and Thermal‐Resistance Properties of K4SrSi3O9:Ce3+

A series of Ce3+‐activated K4SrSi3O9 materials emitting bright blue light under near‐UV excitation was obtained by a facile solid‐state reaction. The luminescence of Ce3+‐doped K4SrSi3O9 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 K4SrSi3O9: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 K4SrSi3O9 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 K4SrSi3O9:Ce3+.