Physicochemical control of valence in luminescence of Cr(III) and V(III, IV) complexes embedded in xero–gel and sol–gel SiO2 glasses
Physicochemical control of valence in luminescence of Cr(III) and V(III, IV) complexes embedded in xero–gel and sol–gel SiO2 glasses
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干凝胶和溶胶凝胶 SiO2 玻璃中 Cr(III) 和 V(III, IV) 配合物发光价态的物理化学控制
DOI：
10.1016/s0022-2313(01)00385-4
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发表时间：
2001
影响因子：
3.6
通讯作者：
T. Sakurai
中科院分区：
文献类型：
--
作者：
M. Morita;S. Kajiyama;T. Kai;D. Rau;T. Sakurai
通过溶胶-凝胶法制备了掺杂过渡金属配合物的溶胶-凝胶二氧化硅玻璃，使用的配合物包括（a）Cr（III）（AA）3（AA =乙酰丙酮），（b）Cr（III）三核碱性乙酸盐（Cr-三聚体），（c）V（III）（AA）3和（d）V（IV）O（AA）2。在 300 至 10K 的温度下测量发光、时间分辨发光、衰减时间、激发和吸收光谱。在低于 150°C 的温度下退火并掺杂 (a) 和 (b) 的玻璃中，发现由于单 Cr(III) 离子和交换耦合 Cr(III) 对而导致 13,000cm−1 处的锐线。在 500°C 以上退火的玻璃中，发现结构宽带是由于通过生成 [Cr(VI)O4]2− 或 [V(V)O4]3− 络离子而发生配体到金属的电荷转移转变。掺杂(c)和(d)的玻璃中的光谱形状、寿命和电子振动结构可以通过假设以下通过增加退火温度的热化学过程来理解：(d)[V(III)(AA)3]→(c)[V(IV)O(AA)2]→[V(V)O4]3−。此外，在温和化学条件下制备的一些玻璃(b)中证实了Cr(III)和Cr(VI)离子的共存。
Sol–gel silica glasses doped with transition metal complexes were prepared by the Sol–gel-method using complexes such as (a) Cr(III)(AA)3(AA=acetylacetonato), (b) Cr(III) tris-nuclear basic acetate (Cr-trimer), (c) V(III)(AA)3, and (d) V(IV)O(AA)2. Luminescence, time-resolved luminescence, decay times, excitation and absorption spectra were measured at temperatures between 300 and 10K. Sharp lines at 13,000cm−1due to single Cr(III) ions and exchange-coupled Cr(III) pairs are found in glasses annealed at temperatures below 150°C, doped with (a) and (b). In the glasses annealed above 500°C, a structured broad band is found to be due to the ligand-to-metal charge transfer transition by generation of either [Cr(VI)O4]2−or [V(V)O4]3−complex ions. The spectral shapes, lifetimes and vibronic structures in glasses doped with (c) and (d) are understood by assuming the following thermo-chemical processes by increase of annealing temperatures: (d)[V(III)(AA)3]→(c)[V(IV)O(AA)2]→[V(V)O4]3−. Moreover, the coexistence of both Cr(III) and Cr(VI) ions is confirmed in some glasses (b) prepared under mild chemical conditions.