Kotadiya Naresh B, Lu Hao, Mondal Anirban, Ie Yutaka, Andrienko Denis, Blom Paul W M, Wetzelaer Gert-Jan A H
Max Planck Institute for Polymer Research, Mainz, Germany.
The Institute of Scientific and Industrial Research (ISIR), Osaka University, Ibaraki, Japan.
Nat Mater. 2018 Apr;17(4):329-334. doi: 10.1038/s41563-018-0022-8. Epub 2018 Feb 19.
Barrier-free (Ohmic) contacts are a key requirement for efficient organic optoelectronic devices, such as organic light-emitting diodes, solar cells, and field-effect transistors. Here, we propose a simple and robust way of forming an Ohmic hole contact on organic semiconductors with a high ionization energy (IE). The injected hole current from high-work-function metal-oxide electrodes is improved by more than an order of magnitude by using an interlayer for which the sole requirement is that it has a higher IE than the organic semiconductor. Insertion of the interlayer results in electrostatic decoupling of the electrode from the semiconductor and realignment of the Fermi level with the IE of the organic semiconductor. The Ohmic-contact formation is illustrated for a number of material combinations and solves the problem of hole injection into organic semiconductors with a high IE of up to 6 eV.
无势垒（欧姆）接触是高效有机光电器件（如有机发光二极管、太阳能电池和场效应晶体管）的关键要求。在此，我们提出了一种简单且稳健的方法，用于在具有高电离能（IE）的有机半导体上形成欧姆空穴接触。通过使用一种中间层，从高功函数金属氧化物电极注入的空穴电流提高了一个多数量级，该中间层唯一的要求是其电离能高于有机半导体。中间层的插入导致电极与半导体之间的静电解耦，并使费米能级与有机半导体的电离能重新对齐。针对多种材料组合展示了欧姆接触的形成，并解决了向高达6 eV高电离能的有机半导体中注入空穴的问题。
