Correa Julián David, Orellana Pedro Alejandro, Pacheco Mónica
Departamento de Ciencias Básicas, Universidad de Medellín, 050026 Medellín, Colombia.
Departamento de Física, Universidad Técnica Federico Santa María, 2340000 Valparaíso, Chile.
Nanomaterials (Basel). 2017 Mar 20;7(3):69. doi: 10.3390/nano7030069.
The search for new optical materials capable of absorbing light in the frequency range from visible to near infrared is of great importance for applications in optoelectronic devices. In this paper, we report a theoretical study of the electronic and optical properties of hybrid structures composed of fullerenes adsorbed on graphene and on graphene nanoribbons. The calculations are performed in the framework of the density functional theory including the van der Waals dispersive interactions. We found that the adsorption of the C 60 fullerenes on a graphene layer does not modify its low energy states, but it has strong consequences for its optical spectrum, introducing new absorption peaks in the visible energy region. The optical absorption of fullerenes and graphene nanoribbon composites shows a strong dependence on photon polarization and geometrical characteristics of the hybrid systems, covering a broad range of energies. We show that an external electric field across the nanoribbon edges can be used to tune different optical transitions coming from nanoribbon-fullerene hybridized states, which yields a very rich electro-absorption spectrum for longitudinally polarized photons. We have carried out a qualitative analysis on the potential of these hybrids as possible donor-acceptor systems in photovoltaic cells.
寻找能够吸收从可见光到近红外频率范围内光的新型光学材料对于光电器件的应用具有重要意义。在本文中，我们报道了由吸附在石墨烯和石墨烯纳米带上的富勒烯组成的混合结构的电子和光学性质的理论研究。计算是在包含范德华色散相互作用的密度泛函理论框架内进行的。我们发现，C60富勒烯在石墨烯层上的吸附不会改变其低能态，但对其光谱有强烈影响，在可见光能量区域引入了新的吸收峰。富勒烯与石墨烯纳米带复合材料的光吸收强烈依赖于混合系统的光子极化和几何特征，覆盖了广泛的能量范围。我们表明，跨越纳米带边缘的外部电场可用于调节来自纳米带 - 富勒烯杂化态的不同光学跃迁，这为纵向极化光子产生了非常丰富的电吸收光谱。我们对这些混合材料作为光伏电池中可能的供体 - 受体系统的潜力进行了定性分析。
