Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
Nanomatch GmbH, Griesbachstraße 5, 76185, Karlsruhe, Germany.
Nat Commun. 2023 Mar 13;14(1):1356. doi: 10.1038/s41467-023-36748-x.
Conductivity doping has emerged as an indispensable method to overcome the inherently low conductivity of amorphous organic semiconductors, which presents a great challenge in organic electronics applications. While tuning ionization potential and electron affinity of dopant and matrix is a common approach to control the doping efficiency, many other effects also play an important role. Here, we show that the quadrupole moment of the dopant anion in conjunction with the mutual near-field host-dopant orientation have a crucial impact on the conductivity. In particular, a large positive quadrupole moment of a dopant leads to an overscreening in host-dopant integer charge transfer complexes. Exploitation of this effect may enhance the conductivity by several orders of magnitude. This finding paves the way to a computer-aided systematic and efficient design of highly conducting amorphous small molecule doped organic semiconductors.
导电机理掺杂已成为克服非晶态有机半导体固有低电导率的不可或缺的方法，这在有机电子应用中是一个巨大的挑战。虽然调节掺杂剂和基质的电离势和电子亲和能是控制掺杂效率的常用方法，但许多其他效应也起着重要作用。在这里，我们表明掺杂剂阴离子的四极矩与施主-受主近场相互取向结合在一起，对电导率有至关重要的影响。特别是，掺杂剂的大的正四极矩导致在主-受主整数电荷转移复合物中过度屏蔽。利用这种效应可以将电导率提高几个数量级。这一发现为通过计算机辅助的系统和高效设计具有高导电性的非晶小分子掺杂有机半导体铺平了道路。
