Mukhopadhyay Arindam, Paulino Victor, Liu Kaixuan, Donley Carrie L, Bernard Brianna, Shomar Alfred, Liu Chuan, Olivier Jean-Hubert
Department of Chemistry, University of Miami, Cox Science Center, 1301 Memorial Drive, Coral Gables, Florida 33146, United States.
Chapel Hill Analytical and Nanofabrication Laboratory, Department of Applied Physical Sciences, University of North Carolina, 243 Chapman Hall, Chapel Hill, North Carolina 27599, United States.
ACS Appl Mater Interfaces. 2021 Jan 27;13(3):4665-4675. doi: 10.1021/acsami.0c18222. Epub 2021 Jan 14.
The functionalization of silicon electrodes with π-conjugated chromophores opens new avenues to engineer hybrid semiconducting interfaces relevant to information storage and processing. Notably, molecularly dissolved π-conjugated units, such as ferrocene derivatives, are traditionally exploited as building blocks to construct well-defined interfaces that establish electrochemically addressable platforms with which to investigate electron transfer properties and charge storage capabilities. In contrast, planar π-conjugated building blocks such as naphthalene diimide (NDI) cores enable the formation of solvated aggregates equipped with emergent electronic structures not manifested by the parent, molecularly dissolved building blocks. To interrogate the extent to which the aggregated states of π-conjugated chromophores can be leveraged to regulate the n-type semiconducting properties of functionalized electrodes, we have devised an amphiphilic rylene core (NDI) that demonstrates a non-negligible degree of aggregation in an aqueous medium. Characterization of the electronic structures of the NDI-derived aggregates using a combination of electrochemistry, reductive titration experiments, and spectroelectrochemistry unveils the existence of π-anion stacks, the formation of which is contingent on the initial concentration of NDI building blocks. We show that grafting n-doped NDI aggregates on silicon electrode precursors equipped with a high density of anchoring groups by means of "click" reaction enables the formation of the hybrid electrode () that facilitates electron injection by more than 400 mV when compared to Si interfaces constructed from molecularly dissolved NDI units. Furthermore, the engineering of a Si precursor surface characterized by a low density of anchoring groups provides additional proof to highlight that the potentiometric properties recorded for originate from NDI units, evidencing a non-negligible degree of aggregation. The present work delivers tools to manipulate the potentiometric properties of functionalized electrodes by leveraging on the electronic structures of aggregated, π-conjugated precursors.
用π共轭发色团对硅电极进行功能化，为设计与信息存储和处理相关的混合半导体界面开辟了新途径。值得注意的是，分子溶解的π共轭单元，如二茂铁衍生物，传统上被用作构建块来构建定义明确的界面，这些界面建立了电化学可寻址平台，用于研究电子转移性质和电荷存储能力。相比之下，平面π共轭构建块，如萘二酰亚胺（NDI）核，能够形成具有母体分子溶解构建块未表现出的新兴电子结构的溶剂化聚集体。为了探究π共轭发色团的聚集态在多大程度上可用于调节功能化电极的n型半导体性质，我们设计了一种两亲性苝核（NDI），它在水介质中表现出不可忽略的聚集程度。通过电化学、还原滴定实验和光谱电化学相结合的方法对NDI衍生聚集体的电子结构进行表征，揭示了π阴离子堆叠的存在，其形成取决于NDI构建块的初始浓度。我们表明，通过“点击”反应将n掺杂的NDI聚集体接枝到配备高密度锚定基团的硅电极前驱体上，能够形成混合电极（），与由分子溶解的NDI单元构建的Si界面相比，该混合电极促进电子注入的能力提高了400 mV以上。此外，对具有低密度锚定基团的Si前驱体表面进行工程设计，进一步证明了记录的电位性质源于NDI单元，表明存在不可忽略的聚集程度。本工作提供了利用聚集的π共轭前驱体的电子结构来操纵功能化电极电位性质的工具。
