Wu An-Ping, Bai He, Bao Jin-Rong, Yang Kui-Suo, Feng Li-Na, Ma Yang-Yang, Qiao Yan, Li Wen-Xian, Liu Ying, Zhu Xiao-Wei
School of Chemistry and Chemical Engineering, Inner Mongolia University Hohhot 010021 China
College of Pharmacology, Inner Mongolia Medical University Hohhot 010059 China
RSC Adv. 2018 Oct 19;8(62):35813-35818. doi: 10.1039/c8ra07260d. eCollection 2018 Oct 15.
The hexagonal and monoclinic phase LaPO and LaPO:Eu nanostructures have been controllably synthesized by a citrate-induced hydrothermal process at 100 °C. The crystal growth of LaPO nanostructures was investigated, and the phase transformation of nanostructured LaPO was systematically studied by varying the citrate concentration, pH value and reaction temperature. When 0.8 mmol of citrate was added into the reaction system, the hexagonal phase LaPO transformed into the monoclinic phase. High concentrations of citrate would lead to the formation of hexagonal phase LaPO. The photoluminescence properties of the monoclinic phase LaPO:Eu prepared using a citrate-induced process demonstrate that the electric dipole transition (D → F) is stronger than the magnetic dipole transition (D → F), which indicated that Eu is in a site with no inversion center. The strongest emission peak of hexagonal phase LaPO:Eu comes from D → F. Furthermore, the citrate-induced hexagonal phase LaPO:Eu has a stronger emission intensity than the hexagonal phase LaPO:Eu prepared not using a citrate-induced process.
通过柠檬酸盐诱导的水热法在100℃下可控合成了六方相和单斜相的LaPO₄和LaPO₄:Eu纳米结构。研究了LaPO₄纳米结构的晶体生长，并通过改变柠檬酸盐浓度、pH值和反应温度，系统地研究了纳米结构LaPO₄的相变。当向反应体系中加入0.8 mmol柠檬酸盐时，六方相LaPO₄转变为单斜相。高浓度的柠檬酸盐会导致六方相LaPO₄的形成。采用柠檬酸盐诱导法制备的单斜相LaPO₄:Eu的光致发光性质表明，电偶极跃迁（D→F）强于磁偶极跃迁（D→F），这表明Eu处于无反演中心的位置。六方相LaPO₄:Eu的最强发射峰来自D→F。此外，柠檬酸盐诱导的六方相LaPO₄:Eu比未采用柠檬酸盐诱导法制备的六方相LaPO₄:Eu具有更强的发射强度。
