Structural and Optical Controls of Mesoscopic Supramolecular Aggregates by the Function of an Interface of Two Phases

伪异氰酸（PIC）染料的J聚集体在云母/水溶液界面上形成，并表现出特有的光学特征。利用原子力显微镜（AFM）原位观察了不同染料浓度下的J聚集体，并首次证实它们具有三维畴岛结构。由于吸收峰波长、线宽或荧光寿命与聚集体的生长过程无关，因此在室温下，物理聚集体尺寸（> ~ 10^6分子）远大于相干尺寸。PIC及其结构类似的不对称菁（AC）染料的混合水溶液在云母/溶液界面形成了汞化J聚集体，并通过测定聚集体的光学、结构和形态性质阐明了聚集体的形成机制。本实验室构建的荧光显微镜系统表明，发射型汞化J聚集体具有介观岛畴形态。当AC摩尔分数较小时，J聚集体完全覆盖界面。随着AC摩尔分数的增加，发射J聚集岛的大小和数量减少，分布离散，但AFM显示界面仍然完全被吸附分子覆盖。我们的研究结果首次表明，染料在PIC/AC混合溶液中的吸附在云母/溶液界面上形成了两种类型的岛域（介观相分离）：发射型合并J聚集体岛（PIC富域）和不含J聚集体的非发射型岛（AC富域）。

The J aggregates of a pseudoisocyanine (PIC) dye were formed at a mica/aqueous solution interface and showed characteristic optical features. The J aggregates at various dye concentrations were in situ observed in solution by atomic force microscopy (AFM), and they were elucidated to possess three-dimensional domain island structures for the first time. Because the absorption peak wavelength, line width, or fluorescence lifetime was independent of the growth processes of the aggregates, the physical aggregation size (>〜10^6 molecules) is suggested to be much larger than the coherence size at room temperature.Aqueous mixed solutions of PIC and its structural analogous asymmetric cyanine (AC) dye formed amalgamated J aggregates at a mica/solution interface, and the formation mechanism of the aggregates was clarified by determining the optical, structural, and morphological properties of such aggregates. The florescence microscopy system constructed in our laboratory showed that the emissive amalgamated J aggregates possessed mesoscopic island domain morphology. The J aggregates covered the interface completely while the AC mole fraction was small. With increasing the AC mole fraction, the emissive J aggregate islands decreased in size and number and were discretely distributed, although AFM showed that the interface was still completely covered by adsorbed molecules. For the first time, our results show that dye adsorption from PIC/AC mixture solutions generated two types of island domain formation at the mica/solution interface (mesoscopic phase separation) : emissive amalgamated J aggregate island (PIC rich domain) and non-emissive island in the absence of J aggregates (AC-rich domain).