Intense green light emission in Sr 2 ZnGe 2 O 7 :Mn 2+ phosphors by the design of high symmetry melilite structure

A green phosphor Sr ZnGe O :Mn with a melilite structure was prepared using a high-temperature solid-state reaction. When the 535 nm emission was monitored, the excitation spectrum of the Sr ZnGe O :Mn was found to contain two excitation bands in the ultraviolet (UV) region. When excited by UV light, the sample shows bright green emission at 535 nm, which corresponds to the distinctive transition of Mn ( T → A ). Moreover, the quantum efficiency of Sr ZnGe O :Mn could reach 67.6%. Finally, a high-performance white-light-emitting diode (WLED) with a low correlated colour temperature of 4632 K and a high colour rendering index (CRI) of 92.3 were packaged by coating commercial blue and red phosphors with an optimized Sr ZnGe O :Mn sample on a 310 nm UV chip. This indicated that Sr ZnGe O :Mn has the potential application as a green component in the WLED lighting field.