Blue, green, and yellow phosphors are obtained in the Sr 1-xY0.98+xCe0.02Si4N 7-xCx system (x=0→1). Decreases in thermal quenching barrier height with x result from a dominant neighboring-cation effect, through which the replacement of Sr2+ by Y3+ reduces the covalency of Ce-N bonding. Green emission is observed from a cation-segregated nanostructure of SrYSi4N7 and Y2Si 4N6C domains in x=0.2-0.6 samples.
- thermal quenching
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