Nitta Jun, Miwa Kazumoto, Komiya Naoki, Annese Emilia, Fujii Jun, Ono Shimpei, Sakamoto Kazuyuki
Department of Nanomaterials Science, Chiba University, Chiba, 263-8522, Japan.
Central Research Institute of Electric Power Industry, Yokosuka, 240-0196, Japan.
Sci Rep. 2019 Jul 4;9(1):9645. doi: 10.1038/s41598-019-46080-4.
A proper understanding on the charge mobility in organic materials is one of the key factors to realize highly functionalized organic semiconductor devices. So far, however, although a number of studies have proposed the carrier transport mechanism of rubrene single crystal to be band-like, there are disagreements between the results reported in these papers. Here, we show that the actual dispersion widths of the electronic bands formed by the highest occupied molecular orbital are much smaller than those reported in the literature, and that the disagreements originate from the diffraction effect of photoelectron and the vibrations of molecules. The present result indicates that the electronic bands would not be the main channel for hole mobility in case of rubrene single crystal and the necessity to consider a more complex picture like molecular vibrations mediated carrier transport. These findings open an avenue for a thorough insight on how to realize organic semiconductor devices with high carrier mobility.
正确理解有机材料中的电荷迁移率是实现高功能化有机半导体器件的关键因素之一。然而，到目前为止，尽管许多研究提出红荧烯单晶的载流子传输机制为带状，但这些论文报道的结果之间存在分歧。在这里，我们表明由最高占据分子轨道形成的电子能带的实际色散宽度比文献中报道的要小得多，并且这些分歧源于光电子的衍射效应和分子的振动。目前的结果表明，在红荧烯单晶的情况下，电子能带不是空穴迁移率的主要通道，并且有必要考虑更复杂的情况，如分子振动介导的载流子传输。这些发现为深入了解如何实现具有高载流子迁移率的有机半导体器件开辟了一条途径。
