Preparation of Germanium Oxide Glasses-Based White and Green Phosphors by a Sol-Gel Method

溶胶-凝胶法制备氧化锗玻璃基白光和绿光荧光粉

基本信息

批准号：
15560590
负责人：
KOJIMA Kazuo
金额：
$ 1.79万
依托单位：
Ritsumeikan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560590/
关键词：
Germanium Oxide Glass Sol-Gel Method White Phosphor Green Phosphor Structural Defects Tb^<3+> Ion Mn^<2+> Ion 残光

项目摘要

The XRD analysis determined the time-temperature-transformation(T-T-T) diagram for sol-gel derived GeO_2 gels heated under various conditions of temperature and time. Sol-gel derived GeO_2 glasses were obtained by heating the gels according to the T-T-T diagram. For comparative purposes, GeO_2 glass was prepared by melt-quenching method. The sol-gel derived glasses showed strong, white luminescence (400-700 nm). White afterglow was also observed under irradiation at 254 and 365 nm. On the other hand, the melt-quenched glass gave a luminescence band at 410 nm, and the afterglow was decayed quickly. The sol-gel derived glass included defects and impurities such as Ge^<2+> center, Ge-OH,H2_O,R-OH (R : alkyl group), CH_3-,-CH_2-,CH_3CH_2-,CO_2,Ge-O-C,GeC,Ge-O-R, and carbon-related radicals, while the melt-quenched glass contained Ge^<2+> and GeE' centers, and Ge-OH. The white luminescence and afterglow observed in the sol-gel derived GeO_2 glass are considered to be caused by the Ge^<2+> c … More enter and Ge-O-C.In Tb^<3+> ions doped GeO_2 glasses, under UV excitation at 254 and 365 nm, fluorescence bands due to the transitions of ^5D_4→^7F_j(j=3,4,5, and 6) in the Tb^<3+> ions appeared at 489,544,586, and 620 nm, respectively. In addition, the Tb^<3+> afterglow was observed and lasted longer with increasing the UV irradiation time. However, when the UV irradiation time was too long, the afterglow disappeared quickly. It is found that the intensity of an absorption band due to the tradition 4f^7→4f^65d^1 of the Tb^<4+> ions increased with an increase in the UV irradiation time. Therefore, it is considered that the afterglow may be affected by the Tb^<4+> ions.Mn ion doped ZnO-GeO_2 glasses and glass ceramics were prepared from solutions of (CH_3COO)_2Zn ・2H_20,Ge(OC_2H_5)_4, and Mn(NO_3)_2 ・6H_2O by a sol-gel method and the subsequent heat treatment up to 1000 ℃. Under UV irradiation of 254 or 365 nm, the glass ceramics showed green luminescence at 535 am, which may be due to the ^4T_1→^6A_1 transition of Mn^<2+> ions incorporated in Zn_2GeO_4 polycrystals. The intensity of this green luminescence strengthened and the crystallinity of Zn_2Ge0_4 became high with increasing the heat-treatment temperature up to 1000O℃. In materials with low crystallinity and large amount of MnO, we observed a broad, featureless ESR signal of g=2.01. On the other hand, in a high-crystallinity and low MnO content sample heat treated at 1000℃, 0.1MnO-40ZnO-60GeO_2, many ESR signals were found in the range of about 20 to 500 mT; typical signals having six hyperfine lines were at g=2.01(A=8.3-8.7 mT) and g=4.27 (A=8.2-8.3 mT). All of these ESR signals are probably due to tetrahedrally coordinated Mn^<2+> ions incorporated in Zn_2GeO_4 polycrystals.Local structure around Er^<3+> and Ge^<3+> ions in sol-gel derived GeO_2 glasses were studied by vibrational and XAFS spectroscopy. Less

XRD分析确定了在不同温度和时间条件下加热的溶胶-凝胶衍生的GeO_2凝胶的时间-温度-转变(T-T-T)图,根据T-T-T图对凝胶进行加热得到凝胶。目的,采用熔融淬火法制备的GeO_2玻璃显示出强烈的白色余辉(400-700 nm)。在 254 和 365 nm 的照射下也观察到了这种现象。另一方面，熔融淬火的玻璃在 410 nm 处产生发光带，并且溶胶-凝胶衍生的玻璃包含缺陷和杂质，例如 Ge 2 。 <2+>中心，Ge-OH，H2_O，R-OH(R：烷基)， CH_3-、-CH_2-、CH_3CH_2-、CO_2、Ge-O-C、GeC、Ge-O-R和碳相关基团，而熔融淬火玻璃含有Ge^<2+>和GeE'中心以及Ge-OH在溶胶-凝胶衍生的 GeO_2 玻璃中观察到的白色发光和余辉被认为是由 Ge^<2+> c ... More 输入和引起的。 Ge-O-C.In Tb^<3+>离子掺杂GeO_2玻璃，在254和365 nm紫外激发下，由于^5D_4→^7F_j(j=3,4,5,和6)的跃迁而产生荧光带Tb ^ 3+ 离子分别出现在489,544,586和620nm处。随着UV照射时间的增加，观察到Tb 3+ 余辉并且持续时间更长，但是发现当UV照射时间太长时，由于传统的4f，所以余辉很快消失。 Tb^<4+>离子的^7→4f^65d^1随着UV照射时间的增加而增加，因此认为余辉可能受到了影响。以(CH_3COO)_2Zn·2H_20、Ge(OC_2H_5)_4、Mn(NO_3)_2·6H_2O溶液为原料,采用溶胶-凝胶法制备了Tb^<4+>离子.Mn离子掺杂的ZnO-GeO_2玻璃和微晶玻璃。然后在254或UV照射下进行高达1000℃的热处理。 365 nm处，玻璃陶瓷在535 am处呈现绿色发光，这可能是由于Zn_2GeO_4多晶中Mn^<2+>离子的^4T_1→^6A_1跃迁增强了这种绿色发光的强度以及Zn_2Ge0_4的结晶度。对于低结晶度的材料，随着热处理温度升高到1000O℃，其温度升高。另一方面，在1000℃热处理的高结晶度、低MnO含量的0.1MnO-40ZnO-60GeO_2样品中，观察到了许多ESR信号。发现在约 20 至 500 mT 的范围内，具有 6 条超细线的典型信号位于g=2.01(A=8.3-8.7 mT) 和 g=4.27 (A=8.2-8.3 mT) 所有这些 ESR 信号可能是由于 Zn_2GeO_4 多晶中掺入了四面体配位的 Mn^<2+> 离子。周围的局部结构。采用振动法研究了溶胶-凝胶法GeO_2玻璃中的Er^<3+>和Ge^<3+>离子和 XAFS 光谱学。