We demonstrate controlled charge trapping and release, accompanied by multiple color changes in a metallo-organic bilayer. The dual functionality of the metallo-organic materials provides fundamental insight into the metal-mediated electron transport pathways. The electrochemical processes are visualized by distinct, four color-to-color transitions: red, transparent, orange, and brown. The bilayer is composed of two elements: 1) a nanoscale gate consisting of a layer of well-defined polypyridyl ruthenium complexes bound to a flexible transparent electrode, and 2) a charge storage layer consisting of isostructural iron complexes attached to the surface of the gate. This gate mediates or blocks electron transport in response to an applied voltage. The charge storage and release depend on the oxidation state of the layer of ruthenium complexes (=gate). Combining electrochemistry with optical data revealed mechanistic information: the brown coloration of the bilayer directly relates to the formation of intermediate ruthenium species, providing evidence for catalytic positive charge release mediated through the gate.

中文翻译：

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双功能纳米级组件：多态电致变色与电荷俘获和释放耦合。

我们展示了可控的电荷俘获和释放，并伴有金属有机双层中的多种颜色变化。金属有机材料的双重功能为金属介导的电子传输途径提供了基本的见识。电化学过程通过不同的四个颜色到颜色的过渡来可视化：红色，透明，橙色和棕色。双层结构由两个元素组成：1）纳米级栅极，由界定在柔性透明电极上的明确定义的聚吡啶钌络合物层组成； 2）电荷存储层，其由附着在栅极表面的同构铁络合物组成。该栅极响应于施加的电压来介导或阻止​​电子传输。电荷的存储和释放取决于钌配合物（栅极）层的氧化态。将电化学与光学数据结合起来可以揭示机理信息：双层的棕色直接与中间钌物种的形成有关，为通过门介导的催化正电荷释放提供了证据。