title: Hydrothermal synthesis and size-enhanced chromaticity of Sr2ZnSi2O7:Eu3+ nanoparticles.
abstract: Red phosphor Sr2ZnSi2O7:Eu3+ nanoparticles with an average diameter of 20 nm were successfully synthesized via a low-temperature hydrothermal route in order to understand the underlying relationship between size and luminescent properties. The nanometer-sized particles result in a distinct improvement in chromaticity and a high quenching concentration. According to emission spectra, the relative intensity of the 5D0 --> 7F2 to 5D0 --> 7F1 transitions in nanometer-sized phosphors is higher than that of the corresponding bulk material. The better chromaticity results from the more distorted lattices and relatively lower crystal symmetry around the Eu3+ ions, which is ascribed to the large surface area due to the nanometer size of the phosphor. Moreover, the nanometer-sized Sr2ZnSi2O7:Eu3+ red phosphor exhibits a shorter fluorescent lifetime and a blue-shift in excitation spectra compared to that of its bulk counterpart. These results indicate that size-induced enhancement of luminescent properties is an efficient way to obtain red phosphors with better chromaticity.
authors.affiliation: Institute of Advanced Materials, Graduate School of Shenzhen, Tsinghua University, Shenzhen, Guangdong 518055, PR China.
authors.forename: Junxi
authors.initials: J
authors.lastname: Wan
authors.forename: Youwei
authors.initials: Y
authors.lastname: Yao
authors.forename: Guoyi
authors.initials: G
authors.lastname: Tang
authors.forename: Yitai
authors.initials: Y
authors.lastname: Qian