Department of Materials Science and Engineering, Rutgers University , 607 Taylor Road, Piscataway, New Jersey 08854, United States.
Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University , 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan.
ACS Nano. 2016 Nov 22;10(11):9899-9908. doi: 10.1021/acsnano.6b03414. Epub 2016 Nov 14.
Hybrid organic-inorganic heterostructures are attracting tremendous attention for optoelectronic applications due to their low-cost processing and high performance in devices. In particular, van der Waals p-n heterojunctions formed between inorganic two-dimensional (2D) materials and organic semiconductors are of interest due to the quantum confinement effects of 2D materials and the synthetic control of the physical properties of organic semiconductors, enabling a high degree of tunable optoelectronic properties for the heterostructure. However, for photovoltaic applications, hybrid 2D-organic heterojunctions have demonstrated low power conversion efficiencies due to the limited absorption from constraints on the physical thickness of each layer. Here, we investigate the ultrafast charge transfer dynamics between an organic polymer:fullerene blend and 2D n-type MoS using transient pump-probe reflectometry. We employ plasmonic metasurfaces to enhance the absorption and charge photogeneration within the physically thin hybrid MoS-organic heterojunction. For the hybrid MoS-organic heterojunction in the presence of the plasmonic metasurface, the charge generation within the polymer is enhanced 6-fold, and the total active layer absorption bandwidth is increased by 90 nm relative to the polymer:fullerene blend alone. We demonstrate that MoS-organic heterojunctions can serve as hybrid solar cells, and their efficiencies can be improved using plasmonic metasurfaces.
由于其低成本处理和器件中的高性能，混合有机-无机异质结构在光电子应用中引起了极大的关注。特别是，由于二维（2D）材料的量子限制效应和有机半导体的物理性质的合成控制，在无机二维（2D）材料和有机半导体之间形成的范德瓦尔斯 p-n 异质结引起了人们的兴趣，从而使异质结构具有高度可调谐的光电性能。然而，对于光伏应用，由于每层物理厚度的限制对吸收的限制，混合二维-有机异质结表现出低的功率转换效率。在这里，我们使用瞬态泵浦-探测反射率研究了有机聚合物：富勒烯混合物和二维 n 型 MoS 之间的超快电荷转移动力学。我们采用等离子体超表面来增强物理上很薄的混合 MoS-有机异质结中的吸收和电荷光生。对于存在等离子体超表面的混合 MoS-有机异质结，聚合物中的电荷生成增强了 6 倍，并且与单独的聚合物：富勒烯混合物相比，总活性层吸收带宽增加了 90nm。我们证明了 MoS-有机异质结可用作混合太阳能电池，并且可以使用等离子体超表面来提高它们的效率。
