Mo^6+ substitution induced band structure regulation and efficient near-UV-excited red emission in NaLaMg(W,Mo)O_6:Eu phosphor

Abstract

In this paper, by changing the ligand-to-metal charge transfer (LMCT) band through Mo6+ substitution, the excitation band of our prepared NaLaMg(W,Mo)O6:Eu3+ sample had been extended largely and could match with the InGaN-based LED chips successfully. Diffuse reflection spectra and photoluminescence properties of NaLaMg(W,Mo)O6:Eu3+ had been investigated as a function of W/Mo ratio. Density functional theory calculations gave an insight into the excitation band regulation on the aspect of band structure. The quantum efficiency together with thermal stability of typical prepared samples had been measured and investigated in detail. Moreover, a red LED device fabricated by a 375 nm UV chip with prepared NaLaMgW0.6Mo0.4O6:0.25Eu3+ phosphor had been obtained. Our study suggested that the NaLa0.75Eu0.25MgW0.6Mo0.4O6 phosphor might have potential value in serving as red component for WLEDs.