Preparation and photoluminescence properties of transparent suspensions of Ca(Y1−Eu )2(MoO4)4 nanophosphors

Abstract A new method was developed to synthesize Ca(Y1−xEux)2(MoO4)4 nanophosphors with diameters of approximately 10 nm by reacting Ca-oleate (along with Y-oleate and Eu-oleate) and tetraoctylammonium (TOA)–MoO4 complexes via a solvothermal reaction. The Ca-oleate, Y-oleate, Eu-oleate, and TOA–MoO4 complexes were prepared using a phase-transfer method. The hydrophobic Ca(Y1−xEux)2(MoO4)4 nanophosphors were soluble in nonpolar solvents, and the resultant suspensions showed no scattering or sedimentation because of the long alkyl chains of the capping agents coating the outer surface of the nanophosphor particles. The photoluminescence emission spectra of the Ca(Y1−xEux)2(MoO4)4 nanophosphors showed an intense peak at 614 nm, which corresponds to the 5D0 → 7F2 transition of the Eu3+ ion in Ca(Y1−xEux)2(MoO4)4. A stable and scattering-free suspension of the Ca(Y1−xEux)2(MoO4)4 nanophosphors can potentially be used in transparent displays as a red-emitting material.