Sol–gel synthesis of CaLa2(MoO4)4:2xSm3+ microparticles: a red-emitting phosphor with splendid thermal stability for near-ultraviolet-based white light-emitting diodes

Abstract

We dealt with the synthesis and photoluminescence (PL) behaviors of the Sm3+-activated CaLa2(MoO4)4 phosphors. Under 404 nm irradiation, the prepared samples emitted the visible red emissions from the intra-4f transitions of Sm3+ ions. The color coordinate and color purity of the achieved red emissions were (0.629, 0.370) and 78.2%, respectively. The PL-emission intensity was revealed to dependent on the dopant concentration and the optimal value was 3 mol%. By means of the theoretical calculation, it was found that the involved concentration quenching mechanism was dominated by the dipole–dipole interaction and the critical distance was 40.69 A. Furthermore, the thermal quenching performance of the resultant phosphors was examined utilizing the temperature-dependent PL-emission spectra and the activation energy was decided to be 0.122 eV. Ultimately, through integrating the synthesized phosphors with a commercial near-ultraviolet chip, a red-emitting light-emitting diode was packaged to explore the feasibility of the Sm3+-activated CaLa2(MoO4)4 phosphors for solid-state lighting applications.