Abstract Strains in graphene play a significant role in graphene-based flexible devices, but many aspects of the domain boundary effects in strained graphene remain unclear, such as the evolution of Raman spectra. Here we present a systematic investigation on the domain boundary effects on the Raman spectra of strained graphene, using a designed strong interface formed by formvar resins. We achieve in single-crystal graphene by far the largest strain up to 2%, significantly improved from the previous highest value of 1.3%, as well as the redshift and splitting for its G and 2D peaks. More importantly, the Raman spectra of strained bi-crystal graphene with a domain boundary show that the spectral evolution follows the same trend as the single crystal, and this trend was also confirmed by the result in polycrystalline graphene, demonstrating that the straining effect on the G and 2D peaks of graphene at strong interfaces is actually independent of its domain boundaries, different from the previous report of graphene deposited on weak interfaces. We attribute it to the efficient interfacial stress transfer at the formvar interfaces, and believe they can provide new insights into the understanding of graphene mechanical behaviors and valuable guidance for graphene-based flexible electronics.

中文翻译：

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强界面处应变石墨烯的拉曼光谱的域边界独立性

摘要 石墨烯中的应变在基于石墨烯的柔性器件中发挥着重要作用，但应变石墨烯中域边界效应的许多方面仍不清楚，例如拉曼光谱的演变。在这里，我们使用由 formvar 树脂形成的设计强界面，对应变石墨烯的拉曼光谱的畴边界效应进行了系统研究。迄今为止，我们在单晶石墨烯中实现了高达 2% 的最大应变，比之前的最高值 1.3% 显着改善，以及其 G 和 2D 峰的红移和分裂。更重要的是，具有畴边界的应变双晶石墨烯的拉曼光谱表明光谱演化遵循与单晶相同的趋势，这种趋势也被多晶石墨烯的结果证实，证明对石墨烯在强界面处的 G 和 2D 峰的应变效应实际上与其域边界无关，这与之前报道的石墨烯沉积在弱界面上不同。我们将其归因于 formvar 界面处的有效界面应力转移，并相信它们可以为理解石墨烯机械行为和基于石墨烯的柔性电子产品的宝贵指导提供新的见解。