The luminescence of potassium siliconiobates

Abstract

The luminescence of K6Nb6Si4O26 and K8Nb14Si4O47 is reported. Three emission bands have been observed, each with its own excitation band. In the case of K8Nb14Si4O47 these emissions can be ascribed to the three crystallographically different niobate octahedra. The emission from the edge-sharing octahedron is exceptional, because the Stokes shift is small and the thermal quenching temperature relatively high. In the case of K6Nb6Si4O26 we are forced to accept the presence of stacking faults in order to explain all the emission bands.