Cation substitution and luminescence properties of Eu2+/Ga3+-codoped Na2ZrSi2O7

Eu2+/Ga3+ co-doped Na2ZrSi2O7 phosphors were prepared via a facile solid-state reaction route. The structural characteristics, photoluminescence spectra, and application performances of Na2-xEuxZr1-xGaxSi2O7 (x= 0, 0.02, 0.04, 0.06, 0.08, 0.10) were investigated. The main motivation of Ga3+ co-doping on Zr4+ is to eliminate the charge imbalance created by the aliovalent substitution of Eu2+ on Na+ sites in the lattices. The results indicated that the Eu2+/Ga3+ co-doped Na2ZrSi2O7 kept a good esseneite-like structure with a triclinic space group of P-1. The phosphor presents a narrow cyan-emitting band centered at 485 nm under near-UV light excitation. The luminescence efficiency of Eu2+ activator was significantly improved through the co-doping of Ga3+ for Zr4+ ions in Na2ZrSi2O7. The maximum luminescence absolute quantum efficiency of 43% was observed in Na2-xEuxZr1-xGaxSi2O7 (x = 0.1) under the excitation of the near-UV light. The phosphor has good thermal stability with an activation energy of 0.31 eV. To realize charge compensation via cation co-substitution could be a practical strategy to improve luminescence in Eu2+-activated phosphors on aliovalent sites.