Wang Chenhao, Chen Xiaotong, Luo Xue, Zhao Junjie, Qiao Xvsheng, Liu Yong, Fan Xianping, Qian Guodong, Zhang Xianghua, Han Gaorong
State Key Laboratory of Silicon Materials & School of Materials Science and Engineering, Zhejiang University Hangzhou 310027 China
School of Materials Science and Engineering, Tianjin University Tianjin 300350 China.
RSC Adv. 2018 Oct 8;8(60):34536-34542. doi: 10.1039/c8ra06843g. eCollection 2018 Oct 4.
Fluorosilicate glasses and glass-ceramics with MF (M = Ca, Sr, Ba), ZnF or LaF components were investigated to host divalent Eu for photoluminescence (PL) application. X-ray diffraction phase identification and a series of spectroscopic analyses were performed to reveal the relationship between microstructure and the reduction of Eu → Eu. The precursor glasses were believed being constituted by silicate-rich phases and fluoride-rich phases, due to the immiscibility of fluoride-and-silicate mixed glass system. After heat treatment, the fluoride-rich glass phases could transform into fluoride crystalline phase in the glass-ceramics. Europium tended to enrich in the fluoride-rich phases in the glasses or in the precipitated fluoride crystalline phases in the glass-ceramics. Small amounts of Eu were reduced to Eu in the glasses where the electronegativity had a crucial impact. In contrast, large amounts of Eu were reduced to Eu in the glass-ceramics containing MF nanocrystals, where the reduction was determined by lattice site substitution. Using ZnAlO containing glass-ceramics as reference, it was evidenced that the similar and a little larger radii between sites and substitution ions are the prerequisite for Eu/M substitution. And using LaF containing glass-ceramics as reference, it was certified that unbalanced charge at substitution sites induce the Eu → Eu reduction.
研究了含有MF（M = Ca、Sr、Ba）、ZnF或LaF成分的氟硅酸盐玻璃和微晶玻璃，以负载二价铕用于光致发光（PL）应用。进行了X射线衍射相鉴定和一系列光谱分析，以揭示微观结构与Eu→Eu还原之间的关系。由于氟化物-硅酸盐混合玻璃系统的不混溶性，前驱体玻璃被认为由富硅酸盐相和富氟化物相组成。热处理后，富氟化物玻璃相在微晶玻璃中可转变为氟化物晶相。铕倾向于在玻璃中的富氟化物相或微晶玻璃中析出的氟化物晶相中富集。在电负性起关键作用的玻璃中，少量的Eu被还原为Eu。相比之下，在含有MF纳米晶体的微晶玻璃中，大量的Eu被还原为Eu，其中还原是由晶格位点取代决定的。以含ZnAlO的微晶玻璃为参考，证明位点与取代离子之间相似且稍大的半径是Eu/M取代的前提条件。以含LaF的微晶玻璃为参考，证明取代位点的电荷不平衡会导致Eu→Eu还原。
