Doping is a critically important strategy to modulate the properties of organic semiconductors (OSCs) to improve their optoelectrical performances. Conventional bulk doping involves the incorporation of foreign molecular species (i.e., dopants) into the lattice of the host OSCs, and thus disrupts the packing of the host OSCs and induces structural defects, which tends to reduce the mobility and (or) the on/off ratio in organic field-effect transistors (OFETs). In this article, we report a highly efficient and highly controllable surface doping strategy utilizing 2D molecular crystals (2DMCs) as dopants to boost the mobility and to modulate the threshold voltage of OFETs. The amount of dopants, i.e., the thickness of the 2DMCs, is controlled at monolayer precision, enabling fine tuning of the electrical properties of the OSCs at unprecedented accuracy. As a result, a prominent increase of the average mobility from 1.31 to 4.71 cm² V⁻¹s⁻¹ and a substantial reduction of the threshold voltage from −18.5 to −1.8 V are observed. Meanwhile, high on/off ratios of up to 10⁸ are retained.

掺杂是调节有机半导体（OSC）的性能以改善其光电性能的至关重要的策略。常规的体掺杂涉及将外来分子种类（即，掺杂剂）掺入宿主OSC的晶格中，从而破坏宿主OSC的堆积并引起结构缺陷，这往往会降低迁移率和（或）on /有机场效应晶体管（OFET）的截止比。在本文中，我们报告了一种高效且高度可控的表面掺杂策略，该策略利用2D分子晶体（2DMC）作为掺杂剂来提高迁移率并调节OFET的阈值电压。掺杂剂的量，即2DMC的厚度以单层精度控制，从而能够以前所未有的精度微调OSC的电性能。结果，观察到平均迁移率从1.31显着增加到4.71cm ² V ^-1 s ^-1，并且阈值电压从-18.5显着降低到-1.8V。同时，可保持高达10 ^8的高开/关比。