Chinese Academy of Sciences Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei Anhui 230026, People's Republic of China.
Dalton Trans. 2018 Jul 24;47(29):9834-9844. doi: 10.1039/c8dt02241k.
A novel green-yellow emitting Ca1.5Mg0.5Si1-xLixO4-δ:Ce3+ phosphor with high quantum efficiency and thermal stability was discovered for applications in near ultraviolet pumped white light-emitting diodes. Its crystal structure was determined with a single-particle diagnosis approach. The Si sites in the SiO4 tetrahedra are reported for the first time to accommodate Li+ ions. This substitution, confirmed by 6Li solid-state NMR and T.O.F. neutron powder diffraction, causes a disordered occupation of Ca/Mg in the Ca3MgSi2O8 host and favors a phase transformation at ∼330 °C, which results in the formation of the novel phosphor. The produced phosphor was efficiently excited by near UV light peaking at 365 and 410 nm and produced broad green-yellow emission with peaks at 500 and 560 nm, respectively. Its quantum efficiency reached 88.4% (internal) and 55.7% (external) under excitation at 365 nm, and 80.5% (internal) and 42.7% (external) under excitation at 410 nm, while the decrease of luminescence intensity at 200 °C was small (∼26%). A WLED lamp with a high color rendering index of Ra = 92.8 was produced with the combination of a 365 nm emitting chip with blue emitting BaMgAl10O17:Eu2+, green-yellow emitting CMSL:0.01Ce, and red emitting Sr2Si5N8:Eu2+ phosphors.
一种新型的绿黄色发射 Ca1.5Mg0.5Si1-xLixO4-δ:Ce3+ 荧光粉，具有高光量子效率和热稳定性，可应用于近紫外光激发的白光发光二极管。其晶体结构采用单粒子诊断方法确定。首次报道了 SiO4 四面体中的 Si 位容纳 Li+ 离子。这种取代，通过 6Li 固态 NMR 和 T.O.F. 中子粉末衍射得到证实，导致 Ca3MgSi2O8 宿主中 Ca/Mg 的无序占据，并有利于在 ∼330°C 发生相变，从而形成新型荧光粉。所制备的荧光粉可有效地被近紫外光激发，峰值分别为 365nm 和 410nm，分别产生 500nm 和 560nm 的宽绿黄色发射。在 365nm 激发下，其量子效率达到 88.4%（内部）和 55.7%（外部），在 410nm 激发下，其量子效率达到 80.5%（内部）和 42.7%（外部），而在 200°C 时发光强度的下降较小（约 26%）。通过将 365nm 发射芯片与蓝色发射 BaMgAl10O17:Eu2+、绿黄色发射 CMSL:0.01Ce 和红色发射 Sr2Si5N8:Eu2+ 荧光粉相结合，制作出显色指数 Ra=92.8 的高显色指数 WLED 灯。
