Research Institute for Electronic Science, Hokkaido University, N20, W10, Sapporo 001-0020, Japan.
J Am Chem Soc. 2011 Apr 6;133(13):4984-90. doi: 10.1021/ja110686t. Epub 2011 Mar 10.
Single-molecule fluorescence photoswitching plays an essential role in ultrahigh-density (Tbits/inch(2)) optical memories and super-high-resolution fluorescence imaging. Although several fluorescent photochromic molecules and fluorescent proteins have been applied, so far, to optical memories and super-high-resolution imaging, their performance is unsatisfactory because of the absence of "non-destructive fluorescence readout capability". Here we report on a new molecular design principle of a molecule having non-destructive readout capability. The molecule is composed of acceptor photochromic diarylethene and donor fluorescent perylenebisimide units. The fluorescence is reversibly quenched when the diarylethene unit converts between the open- and the closed-ring isomers upon irradiation with visible and UV light. The fluorescence quenching is based on an electron transfer from the donor to the acceptor units. The fluorescence photoswitching and non-destructive readout capability were demonstrated in solution (an ensemble state) and at the single-molecule level. Femtosecond time-resolved transient and fluorescent lifetime measurements confirmed that the fluorescence quenching is attributed to the intramolecular electron transfer.
单分子荧光光开关在超高密度（Tbits/平方英寸）光学存储器和超高分辨率荧光成象中起着至关重要的作用。尽管已经有几种荧光光致变色分子和荧光蛋白被应用于光学存储器和超高分辨率成象中，但由于缺乏“非破坏性荧光读出能力”，它们的性能仍不尽人意。在这里，我们报道了一种具有非破坏性读出能力的分子的新分子设计原理。该分子由受主光致变色二芳基乙烯和给体荧光苝二酰亚胺单元组成。当二芳基乙烯单元在可见光和紫外光照射下在开环和闭环异构体之间转换时，荧光可逆猝灭。荧光猝灭基于从给体到受体单元的电子转移。荧光光开关和非破坏性读出能力在溶液（集合态）和单分子水平上得到了证明。飞秒时间分辨瞬态和荧光寿命测量证实，荧光猝灭归因于分子内电子转移。
