论文标题
单层MOS2的近乎统一分子掺杂效率
Near Unity Molecular Doping Efficiency in Monolayer MoS2
论文作者
论文摘要
用有机电子供体（OEDS）进行表面功能化是二维（2D）材料的有效掺杂策略，可以实现传统电场门控的掺杂水平。尽管在许多2D系统中已经证明了表面功能的有效性，但OED的掺杂效率在很大程度上是未计量的，这与它们的精度合成和量身定制的氧化还原电位形成了鲜明对比。在这里，将单层MOS2用作模型系统和基于4,4-二吡啶（DMAP-OED）作为强的有机掺杂剂的有机还原剂，我们确定DMAP-OED对MOS2的掺杂效率在每个分子的0.63至1.26个电子范围内。我们还通过表面功能化在单层MOS2中达到了迄今为止的最高掺杂水平，并证明DMAP-OED比以前是最佳OED掺杂剂的苯甲酰Viologen更强的掺杂剂。掺杂效率的测量范围与第一原理计算所预测的值非常吻合。我们的工作为高级掺杂2D材料的OED设计提供了基础。
Surface functionalization with organic electron donors (OEDs) is an effective doping strategy for two-dimensional (2D) materials, which can achieve doping levels beyond those possible with conventional electric field gating. While the effectiveness of surface functionalization has been demonstrated in many 2D systems, the doping efficiencies of OEDs have largely been unmeasured, which is in stark contrast to their precision syntheses and tailored redox potentials. Here, using monolayer MoS2 as a model system and an organic reductant based on 4,4-bipyridine (DMAP-OED) as a strong organic dopant, we establish that the doping efficiency of DMAP-OED to MoS2 is in the range of 0.63 to 1.26 electrons per molecule. We also achieve the highest doping level to date in monolayer MoS2 by surface functionalization and demonstrate that DMAP-OED is a stronger dopant than benzyl viologen, which was the previous best OED dopant. The measured range of the doping efficiency is in good agreement with the values predicted from first-principles calculations. Our work provides a basis for the rational design of OEDs for high-level doping of 2D materials.
