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.

无障碍（欧姆）接触是高效有机光电器件（例如有机发光二极管，太阳能电池和场效应晶体管）的关键要求。在这里，我们提出了一种简单而可靠的方法，以高电离能（IE）在有机半导体上形成欧姆孔接触。通过使用中间层，从高功函数金属氧化物电极注入的空穴电流提高了一个数量级以上，对于中间层，唯一的要求是其具有比有机半导体更高的IE。插入中间层会导致电极与半导体发生静电解耦，并使费米能级与有机半导体的IE重新对齐。