Eu3+, Sm3+ Co-Doped La0.8Y0.2PO4: A Novel and Potential Red-Emitting Phosphor for UV-Based White Light-Emitting Diodes

A series of single-phase Eu3+, Sm3+ co-doped La0.8Y0.2PO4 phosphors were synthesized by solid-state reaction at 850 degrees C. Crystal structures of the phosphors were examined by X-ray Diffraction analyses. A monoclinic phase was confirmed. The excitation (PLE) and emission (PL) spectra showed that the phosphors could emit red light centered at 591 nm under the 391 nm excitation, which was in good agreement with the emission wavelength from near-ultraviolet (n-UV) LED chip (370-410 nm). The optimal molar concentration of Sm3+ was found to be 1.20%, when the molar concentration of Eu3+ was 3.0%. Co-doping Sm3+ ions can not only broaden and enhance the absorption of near UV region, but also increase the D-5(0) -> F-7(2) to D-5(0) -> F-7(1) emission intensity ratio. It can also be efficient to sensitize the emission of the Eu3+, Sm3+ co-doped La0.8Y0.2PO4 phosphors, indicating that the involved energy transfer occurs from Sm3+ to Eu3+ ions. Our research results displayed that Eu3+, Sm3+ co-doped La0.8Y0.2PO4 phosphors could represent a potential red-emitting phosphor for UV-based white LEDs.