Department of Physics and I3N, University of Aveiro , Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Nano Lett. 2014 Jul 9;14(7):3817-26. doi: 10.1021/nl500932q. Epub 2014 Jun 3.
The future exploitation of the exceptional properties of nanocrystal (NC) thin films deposited from liquid dispersions of nanoparticles relies upon our ability to produce films with improved electrical properties by simple and inexpensive means. Here, we demonstrate that the electronic conduction of solution-processed NC films can be strongly enhanced without the need of postdeposition treatments, via specific molecules adsorbed at the surfaces of adjacent NCs. This effect is demonstrated for Si NC films doped with the strong molecular oxidizing agent tetrafluoro-tetracyanoquinodimethane (F4-TCNQ). Density functional calculations were carried out with molecule-doped superlattice solid models. It is shown that, when populated by electrons, hybrid molecule/NC states edge (and may actually resonate with) the conduction-band states of the NC solid. This provides extra electronic connectivity across the NC network as the molecules effectively flatten the electronic potential barriers for electron transfer across the otherwise vacuum-filled network interstitialcies.
未来对纳米晶体（NC）薄膜的特殊性质的开发利用依赖于我们通过简单而廉价的手段生产具有改进的电性能的薄膜的能力。在这里，我们证明了通过吸附在相邻 NC 表面上的特定分子，无需后沉积处理即可显著增强溶液处理 NC 薄膜的电子传导。对于用强分子氧化剂四氟-四氰基对醌二甲烷（F4-TCNQ）掺杂的 Si NC 薄膜，证明了这种效果。使用掺杂分子的超晶格固体模型进行了密度泛函计算。结果表明，当被电子填充时，混合分子/NC 态的边缘（实际上可能与）NC 固体的导带态共振。这为 NC 网络提供了额外的电子连接性，因为分子有效地使电子转移的电子势垒变平，否则真空填充的网络间隙会阻碍电子转移。
