德国柏林理工大学Mario Dähne团队报道了硅上N-杂环卡宾有序单分子膜的控制生长。相关研究成果于2021年6月21日发表在国际顶尖学术期刊《自然—化学》。

N-杂环卡宾（NHCs）是一种很有前途的表面功能化改性剂和锚定剂，与硫醇基体系相比具有许多优点。由于NHCs具有很强的结合亲和力和高的电子供给能力，NHCs能显著改变其结合表面的性质。目前，高度有序的NHC单分子膜仅限于金属表面。然而，硅仍然是半导体器件的首选元素，因此硅的改性对电子工业至关重要。

该文对NHCs在硅上的吸附进行了全面的研究。研究人员发现共价键合的NHC分子具有直立的吸附几何结构，并展示形成的高度有序的单分子膜，其表现出良好的热稳定性和很强的功函数降低特征。单分子膜的结构和有序性受底物的几何形状和反应性，特别是NHC侧基的控制。

该发现为硅表面量身定做的有机功能化铺平了道路，并且由于NHCs的高度模块化，为新的电子和光电应用铺平了道路。

附：英文原文

Title: Controlled growth of ordered monolayers of N-heterocyclic carbenes on silicon

Author: Martin Franz, Sandhya Chandola, Maximilian Koy, Robert Zielinski, Hazem Aldahhak, Mowpriya Das, Matthias Freitag, Uwe Gerstmann, Denise Liebig, Adrian Karl Hoffmann, Maximilian Rosin, Wolf Gero Schmidt, Conor Hogan, Frank Glorius, Norbert Esser, Mario Dhne

Issue&Volume: 2021-06-21

Abstract: N-Heterocyclic carbenes (NHCs) are promising modifiers and anchors for surface functionalization and offer some advantages over thiol-based systems. Because of their strong binding affinity and high electron donation, NHCs can dramatically change the properties of the surfaces to which they are bonded. Highly ordered NHC monolayers have so far been limited to metal surfaces. Silicon, however, remains the element of choice in semiconductor devices and its modification is therefore of utmost importance for electronic industries. Here, a comprehensive study on the adsorption of NHCs on silicon is presented. We find covalently bound NHC molecules in an upright adsorption geometry and demonstrate the formation of highly ordered monolayers exhibiting good thermal stability and strong work function reductions. The structure and ordering of the monolayers is controlled by the substrate geometry and reactivity and in particular by the NHC side groups. These findings pave the way towards a tailor-made organic functionalization of silicon surfaces and, thanks to the high modularity of NHCs, new electronic and optoelectronic applications.

DOI: 10.1038/s41557-021-00721-2

Source: https://www.nature.com/articles/s41557-021-00721-2