Han Mina, Hara Masahiko
Local Spatio-Temporal Functions Laboratory, Frontier Research System, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
J Am Chem Soc. 2005 Aug 10;127(31):10951-5. doi: 10.1021/ja0509275.
We describe here the highly fluorescent self-assembled spherical aggregates of an azobenzene molecule without a specific ionic component in organic solution under UV light illumination. The first stage of trans-to-cis photoisomerization by UV light at 365 nm was followed by a significant enhancement, up to about 1000 times, of the emission from an azobenzene molecule (CN2Azo) with a long alkyl chain, which is due to the spontaneous formation of spherical organic aggregates. Fluorescence emission was further enhanced in the dark, and the quantum yield increased to about 0.3. We also report the significant size and structural changes of the aggregates, from nanometer-scale micelle-like aggregates to micrometer-scale vesicular aggregates, obtained only from the variation in the concentration of an azobenzene derivative. The light-driven azobenzene aggregates show the size and structure dependences of emission wavelength from violet-blue to green-yellow.
我们在此描述了一种偶氮苯分子在紫外光照射下于有机溶液中形成的高度荧光自组装球形聚集体，该分子在有机溶液中没有特定的离子成分。在365 nm紫外光作用下，反式到顺式的光异构化的第一阶段之后，具有长烷基链的偶氮苯分子（CN2Azo）的发射显著增强，增强倍数高达约1000倍，这是由于球形有机聚集体的自发形成。在黑暗中荧光发射进一步增强，量子产率增加到约0.3。我们还报告了仅通过改变偶氮苯衍生物的浓度而获得的聚集体的显著尺寸和结构变化，从纳米级的胶束状聚集体变为微米级的囊泡状聚集体。光驱动的偶氮苯聚集体显示出发射波长从紫蓝色到绿黄色的尺寸和结构依赖性。
