离域对部分氧化石墨烯稳定性和带隙的拓扑影响,ACS Omega

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离域对部分氧化石墨烯稳定性和带隙的拓扑影响
ACS Omega ( IF 3.7 ) Pub Date : 2023-01-26 , DOI: 10.1021/acsomega.2c08169
Gaurav Jhaa ₁ , Pattath D Pancharatna ₁ , Musiri M Balakrishnarajan ₁

Affiliation

对石墨烯框架施加可调谐能带隙的战略扰动有望实现比硅更小、更快、更灵活且更高效的智能电子产品。尽管有不同的化学方案，但用于微观管理带隙的明确可扩展策略仍然滞后。由于电导率来自离域的 π 电子，化学直觉表明某些 sp ^{2的选择性饱和}碳将允许对带隙进行战略控制。然而，不同二维π-离域拓扑的逻辑认知是复杂的。它们对热力学稳定性和带隙的影响仍然未知。使用部分氧化的石墨烯及其容易和可逆的环氧化物，我们表明离域对边界带的性质具有压倒性的影响。可以有效地使用超共轭、共轭、芳香性等有机电子效应来了解离域的影响。通过保持恒定的 C ₄O 化学计量学，直接评估各种 π-离域拓扑结构的相对稳定性，而无需借助共振能量概念。我们的结果表明 >C═C< 和芳香族六重态是两个基本块，导致孤立的大带隙。将离域扩展到这些单元将以带隙为代价增加稳定性。带隙与 π 框架内的键交替程度直接相关，强制单键/双键会导致较大的带隙。此外，它还为二维系统中与 π 离域相关的热力学稳定性建立了基本规则。我们预计我们的发现将为使用化学直觉设计具有所需带隙和稳定性的部分饱和石墨烯提供启发式指导。

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Topological Impact of Delocalization on the Stability and Band Gap of Partially Oxidized Graphene

Strategic perturbations on the graphene framework to inflict a tunable energy band gap promises intelligent electronics that are smaller, faster, flexible, and much more efficient than silicon. Despite different chemical schemes, a clear scalable strategy for micromanaging the band gap is lagging. Since conductivity arises from the delocalized π-electrons, chemical intuition suggests that selective saturation of some sp² carbons will allow strategic control over the band gap. However, the logical cognition of different 2D π-delocalization topologies is complex. Their impact on the thermodynamic stability and band gap remains unknown. Using partially oxidized graphene with its facile and reversible epoxides, we show that delocalization overwhelmingly influences the nature of the frontier bands. Organic electronic effects like hyperconjugation, conjugation, aromaticity, etc. can be used effectively to understand the impact of delocalization. By keeping a constant C₄O stoichiometry, the relative stability of various π-delocalization topologies is directly assessed without resorting to resonance energy concepts. Our results demonstrate that >C═C< and aromatic sextets are the two fundamental blocks resulting in a large band gap in isolation. Extending the delocalization across these units will increase the stability at the expense of the band gap. The band gap is directly related to the extent of bond alternation within the π-framework, with forced single/double bonds causing the large gap. Furthermore, it also establishes the ground rules for the thermodynamic stability associated with the π-delocalization in 2D systems. We anticipate that our findings will provide the heuristic guidance for designing partially saturated graphene with the desired band gap and stability using chemical intuition.

更新日期：2023-01-26

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