Oscillating fluorescence in an unstable colloidal dispersion of CdSe/ZnS core/shell quantum dots.
Oscillating fluorescence in an unstable colloidal dispersion of CdSe/ZnS core/shell quantum dots.
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DOI：
10.1021/la0489211
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发表时间：
2004-08
期刊：
影响因子：
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通讯作者：
A. Komoto;S. Maenosono;Y. Yamaguchi
中科院分区：
文献类型：
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作者：
A. Komoto;S. Maenosono;Y. Yamaguchi
研究了分散在非极性溶剂中的胶体CdSe/ZnS核壳量子点体系在连续光照下的荧光振荡现象。分散在甲苯中的量子点逐渐聚集并改变其荧光强度，即使在黑暗中。在聚集过程中，QD/甲苯悬浮液是不稳定的，即过度分散。在系统达到稳态之前，只有在这种不稳定状态下才有荧光振荡。此外，聚集速率被辐射促进，并且与振荡幅度强烈相关。我们的实验结果表明，色散不稳定性在荧光的线性和非线性动力学中都起着重要作用。从实验结果和先前的研究推断，在QD/甲苯分散体中的荧光的复杂的时间演化可能是由于在QD聚集的过程中的表面配体分子的吸附和脱附。
Fluorescence oscillation is observed in an ensemble of colloidal CdSe/ZnS core/shell quantum dots (QDs) dispersed in nonpolar solvent under continuous irradiation. The QDs dispersed in toluene gradually aggregate and change their fluorescence intensity, even in the dark. During the aggregation, the QD/toluene suspension is unstable, that is, overdispersed. The fluorescence oscillation is found only in this unstable state before the system reaches steady state. In addition, the aggregation rate is promoted by irradiation and strongly correlates with the oscillation amplitude. Our experimental results indicate that the dispersion instability plays an important role in both linear and nonlinear dynamics of the fluorescence. It is inferred from the experimental results and previous studies that the complex time evolution of fluorescence in the QD/toluene dispersion is possibly due to adsorption and desorption of surface ligand molecules over the course of QD aggregation.