Effect of various cerium sources on the emission intensity of Ce3+-doped La3Si6N11 phosphor for high-power white light emitting diodes

Abstract

La3Si6N11:Ce3+ (LSN:Ce3+) phosphor has attracted widespread attention in the field of high-power white light-emitting diodes as it can be effectively excited by blue LED chip and exhibits excellent thermal quenching. To improve the emission intensity is always the critical objective of La3Si6N11:Ce3+. In this paper, the strategy by combining CeO2 and CeN as cerium sources of the activator was developed to enhance the emission intensity. The emission intensity of NO-LSN:Ce3+ is 112.8% of that of N-LSN:Ce3+, which benefits from the enhancement of the concentration of Ce3+ ions. Generally, more Ce4+ ions can enter into the lattice of La3Si6N11 at high concentration due to the smaller ionic radius of Ce4+ than Ce3+. After that, Ce4+ ions can be effectively reduced to Ce3+ ions at high temperature. The luminescence improvement mechanism of as-prepared phosphors was analyzed. This research provides an effective method for improving the emission intensity of nitride or oxy-nitride phosphors.