Sol-gel synthesis of CaLa_2(MoO_4)_4:2xSm~(3+) microparticles: a red-emitting phosphor with splendid thermal stability for near-ultraviolet-based white light-emitting diodes

摘要

We dealt with the synthesis and photoluminescence (PL) behaviors of the Sm3+-activated CaLa2(MoO4)(4) phosphors. Under 404nm 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 3mol%. 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 angstrom. 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 0.122eV. 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.