Molten-Salt-Assisted Synthesis of Na3Bi(PO4)2: Eu3+ Nanoparticles with Strong Red Emission

Single phase Eu3+-doped Na3Bi(PO4)(2) (NBPO) nanoparticles with different Eu3+ concentrations are successfully synthesized by a molten-salten method using Na3PO4 center dot 12H(2)O both as reaction medium and as reactant. The influence of synthesis conditions such as the Na3PO4 center dot 12H(2)O content, heating temperature, and time on the crystal structure of the final products is investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It reveals that pure phase Na3Bi(PO4)(2) nanoparticles with size about 100 nm are successfully achieved when the mixture (molar ratio of 1:4 between Bi(NO3)(3)center dot 5H(2)O and Na3PO4 center dot 12H(2)O) is heated at 180 degrees C for 12h. After Eu3+-doping, NBPO:Eu3+ nanoparticles exhibit bright red emission peaking at 620 nm under the excitation of the near ultraviolet (NUV) light. The luminescence is attributed to the electric dipole transition 'Do 'F2 of Eu3+ ions. The luminescent intensity of the NBPO:Eu3+ phosphors is strongly dependent on the Eu3+ content and concentration quenching occurred when the Eu3+ concentration is larger than 8 mol%, which is attributed to dipole-dipole interaction. This work provides a green way for the synthesis of phosphate-based nanomaterials and suggests that Eu3+-doped Na3Bi(PO4)(2) has a great potential application in the lighting and display fields.