Modulating the Conduction Band Energies of Si Electrode Interfaces Functionalized with Monolayers of a Bay-Substituted Perylene Bisimide
Modulating the Conduction Band Energies of Si Electrode Interfaces Functionalized with Monolayers of a Bay-Substituted Perylene Bisimide
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调节用湾取代苝双酰亚胺单层功能化的硅电极界面的导带能量
DOI：
10.1021/acs.langmuir.1c03423
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发表时间：
2022
期刊：
影响因子：
3.9
通讯作者：
Olivier, Jean-Hubert
中科院分区：
文献类型：
--
作者：
Mukhopadhyay, Arindam;Liu, Kaixuan;Paulino, Victor;Olivier, Jean-Hubert
将π共轭的发色团限制在硅电极表面是设计与微电子学、电催化、信息存储与处理相关的电响应性单分子膜的有效途径。虽然常用的使硅界面功能化的策略是利用分子溶解的构件，但只有少数研究利用π聚集体的结构-功能关系来调节硅界面上杂化单分子层的电子结构。在这里，我们证明了构建在硅电极上的n型单分子膜的半导体性质与π共轭发色团前驱体的初始聚集状态密切相关。具体地说，我们的研究揭示了对于使用PbIπ聚集体设计的N型单分子膜，将负电荷载流子注入导带所需的阴极还原电位可以通过可逆切换氧化循环中施加的最大阳极电位(MAP)稳定295 mV(+0.5V或+1.5Vvs Ag/AgCl.)。这种氧化还原辅助的稳定效应对于由分子溶解的PBI核心衍生的n型单层和具有低表面密度的氧化还原活性探针的单层来说是观察不到的。这些发现明确地指出了PbIπ聚集体在调制n型单分子膜的导带能量中所起的关键作用，其中+1.5V的高映射使电子陷阱态的形成在扫描回到阴极电位时有利于电子注入。由于PbIπ聚集体的结构-功能关系被证明可以调节构建在Si界面上的杂化单层的半导体性质，我们的结果为开发用于工程非易失性电子存储器件的氧化还原可开关单层提供了很好的机会。
The confinement of π-conjugated chromophores on silicon (Si) electrode surfaces is a powerful approach to engineer electroresponsive monolayers relevant to microelectronics, electrocatalysis, and information storage and processing. While common strategies to functionalize Si interfaces exploit molecularly dissolved building blocks, only a handful number of studies have leveraged the structure–function relationships of π-aggregates to tune the electronic structures of hybrid monolayers at Si interfaces. Herein, we show that the semiconducting properties ofn-type monolayers constructed on Si electrodes are intimately correlated to the initial aggregation state of π-conjugated chromophore precursors derived from bay-substituted perylene bisimide (PBI) units. Specifically, our study unravels that forn-type monolayers engineered using PBI π-aggregates, the cathodic reduction potentials required to inject negative charge carriers into the conduction bands can be stabilized by 295 mV through reversible switching of the maximum anodic potential (MAP) that is applied during the oxidative cycles (+0.5 or +1.5 V vs Ag/AgCl). This redox-assisted stabilization effect is not observed withn-type monolayers derived from molecularly dissolved PBI cores and monolayers featuring a low surface density of the redox-active probes. These findings unequivocally point to the crucial role played by PBI π-aggregates in modulating the conduction band energies ofn-type monolayers where a high MAP of +1.5 V enables the formation of electronic trap states that facilitate electron injection when sweeping back to cathodic potentials. Because the structure–function relationships of PBI π-aggregates are shown to modulate the semiconducting properties of hybridn-type monolayers constructed at Si interfaces, our results hold promising opportunities to develop redox-switchable monolayers for engineering nonvolatile electronic memory devices.