Liang-Jun Yin

High Photoluminescence of Si–N-Co-Doped BaAl12O19 : Mn2 + Green Phosphors

A simple efficient method has been proposed to improve the photoluminescence properties of BaAl 12 O 19 :Mn 2+ green phosphors by the substitution of Si―N bonds for some Al―O bonds in the host crystal. The incorporation of Si―N bonds only led to a reduction in the lattice parameters, but significantly enhanced the photoluminescence intensity both under UV-visible and vacuum UV excitations. These could be ascribed to the relaxation of the spin and parity prohibitions of Mn 2+ d ― d transitions and the efficient energy transfer from the host lattice to the activator, respectively.

Optimization mechanism of CaSi2O2N2 : Eu2+ phosphor by La3+ ion doping

La3+(lanthanide 3+) ion doping may significantly improve the photoluminescence properties of CaSi2O2N2 : Eu2+, a potential yellow–green phosphor for ultraviolet or blue light-emitting diodes. The optimization mechanism was studied in detail by the case of La3+ doping. The La3+ ions could stabilize Ca2+ vacancies, inhibit the oxidization of Eu2+ to Eu3+, based on x-ray photoelectron spectroscopy, x-ray absorption near-edge structure measurements and first-principles calculations. Consequently, not only could the total number of activators be increased, but also the non-radiative transition probability between Eu2+ and Eu3+ could be reduced as a result of La3+ doping. It was also observed that the photoluminescence of CaSi2O2N2 : Eu2+ phosphors could be enhanced by the addition of many La3+ ions, but not Sm3+ and Yb3+ ions, which confirmed the mechanism.

Optimization of BaMgAl10O17:Eu2+ phosphors by the substitution of Si-N bonds for Al-O bonds

Abstract We proposed a simple method to improve the thermal stability of BaMgAl10O17:Eu2+ (BAM) phosphors by the substitution of Si-N bonds for Al-O bonds in the host lattice. Both photoluminescence properties and thermal stability under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation could be significantly improved through Si-N incorporation. After thermal degradation at 600 °C for 1 h in air atmosphere, the Si-N doped sample (Ba0.88Eu0.12MgAl9.97Si0.03O16.97N0.03) had the highest emission intensity which was 22% and 40% stronger than that of as-received sample under UV and VUV excitation, respectively. This could be attributed to the stable local structure surrounding the Eu2+ ions and the lower electronegativity of nitrogen.