Site-related broadband sensitization in La3Ga5.5Nb0.5O14: Cr3+, Ln3+(Ln = Yb, Er) phosphors

Abstract Yb3+ 1000 nm and Er3+ 1536 nm emission can be efficiently sensitized by broadband absorption of Cr3+ in almost the whole visible region in La3Ga5.5Nb0.5O14(LGNO): Cr3+, Ln3+ (Ln = Yb, Er) phosphor. Between the two kinds of Cr3+ sites, tetrahedral Cr(II) mainly behaves as the broadband sensitizer for Er3+ or Yb3+. Meanwhile octahedral Cr(I) may energy transfer (ET) to Cr(II), thereby influences the luminescence decay of Cr(II) as increasing Er3+ or Yb3+ content. This kind of site-related broadband sensitization may propose a strategy of designing tunable ET process between transition metal ions and rare earth ions.