Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010, Graz, Austria.
Adv Mater. 2017 Jul;29(27). doi: 10.1002/adma.201700888. Epub 2017 May 10.
An innovative strategy for electrostatically designing the electronic structure of 3D bulk materials is proposed to control charge carriers at the nanoscale. This is achieved by shifting the electronic levels of chemically identical semiconducting elements through the periodic arrangement of polar functional groups. For the example of covalent organic networks, by first-principles calculations, the resulting collective electrostatic effects are shown to allow a targeted manipulation of the electronic landscape such that spatially confined pathways for electrons and holes can be realized. Mimicking donor-acceptor bulk heterojunctions, the new materials hold high promise for photovoltaic applications. The distinct advantage over the conventional approach of splitting excitons through chemically distinct donor and acceptor units is that here the magnitude of the band offset can be continuously tuned by varying the dipole density. A particularly promising feature of the suggested strategy is its structural versatility, which also enables the realization of more complex quantum structures such as quantum-cascades and quantum-checkerboards.
提出了一种静电设计 3D 体材料电子结构的创新策略，以在纳米尺度上控制电荷载流子。这是通过在周期性排列的极性官能团中移动化学相同的半导体元素的电子能级来实现的。以共价有机网络为例，通过第一性原理计算，结果表明，这种集体静电效应可以实现对电子景观的有针对性的操纵，从而实现电子和空穴的空间限制途径。模拟给体-受体体异质结，这些新材料在光伏应用中具有很高的应用前景。与通过化学上不同的给体和受体单元分裂激子的传统方法相比，其显著优势在于通过改变偶极子密度可以连续调谐带隙。所提出策略的一个特别有前途的特征是其结构的多功能性，这也使得实现更复杂的量子结构，如量子级联和量子棋盘成为可能。
