Novel red-emitting phosphor La2Ti6O15:Eu3+ for fabricating warm white LED-devices

Abstract

Eu3+-doped La2Ti6O15 nanoparticles were prepared by the sol-gel process. The phase-formations, crystal structure, photoluminescence properties, and lighting application were reported. La2Ti6O15 has band energy of 3.6 eV, which can be narrowed with the increase of Eu3+-doping in the lattices. A broad intrinsic emission band (400–750 nm) peaked at 515 nm was observed at 300 K Eu3+-doped La2Ti6O15 phosphors present bright red-luminescence from 5D0→7F2 transitions (615 nm). The luminescence has an excellent thermal stability performance with an activation energy of ΔE = 0.33 eV. Importantly, it fits well with the commercial LED-chip because of its efficient excitation in blue (465 nm) and near-UV region (395 nm). Red-LED device packaged with the optimal phosphor was achieved with luminous efficiency of 43.75 lm/W. It was suggested that La2Ti6O15:Eu3+ could be a potential candidate for fabricating high-power warm white-LEDs.