Key Laboratory of Modern Acoustics, Ministry of Education, Institute of Acoustics, Nanjing University, Nanjing 210093, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Feb;75(2):543-6. doi: 10.1016/j.saa.2009.11.009. Epub 2009 Nov 11.
Lanthanide complexes Ln(p-ABA)(3).H(2)O (p-ABA: p-aminobenzoic acid; Ln(3+):La(3+), Tb(3+) and Er(3+)) have been incorporated into silica gels via a sol-gel method. Upon heat treatment at 120 degrees C, photoacoustic (PA) intensity of the ligand increases for Tb(3+), La(3+) and Er(3+) complexes in silica gels, respectively, while this difference cannot be observed for the samples without heat treatment. Different PA intensities of the samples are interpreted by comparison with their luminescence spectra. The nephelauxetic parameters and PA branching vectors of Er(3+) complex in silica gel have been calculated. Spectral results indicate that p-ABA does not coordinate with lanthanide ions in silica matrix without a suitable heat treatment. For the co-doped samples, it is shown that the emissions of Tb(3+) are enhanced with addition of La(p-ABA)(3).H(2)O and remarkably quenched with the addition of Er(p-ABA)(3).H(2)O. The possible mechanisms for these phenomena are proposed.
镧系配合物 Ln(p-ABA)(3).H(2)O（p-ABA：对氨基苯甲酸；Ln(3+)：La(3+)、Tb(3+)和 Er(3+)）已通过溶胶-凝胶法掺入硅胶中。在 120°C 下热处理后，硅胶中 Tb(3+)、La(3+)和 Er(3+)配合物的光声（PA）强度分别增加，而未经热处理的样品则观察不到这种差异。通过与它们的发光光谱进行比较，解释了样品的不同 PA 强度。计算了 Er(3+)配合物在硅胶中的离域参数和 PA 分支向量。光谱结果表明，在没有适当热处理的情况下，p-ABA 不会与硅胶基质中的镧系离子配位。对于共掺杂样品，表明添加 La(p-ABA)(3).H(2)O 可以增强 Tb(3+)的发射，而添加 Er(p-ABA)(3).H(2)O 则会显著猝灭。提出了这些现象的可能机制。
