Step edge-mediated assembly of periodic arrays of long graphene nanoribbons on Au(111)

TL;DR

This study demonstrates how substrate steps on Au(111) surfaces facilitate the assembly of longer, periodic graphene nanoribbons by promoting polymer stacking and modifying growth processes, leading to improved nanoribbon length and order.

Contribution

It reveals the role of substrate steps in controlling GNR assembly and introduces a modified growth process to produce longer, periodic nanoribbons.

Findings

Longer GNR arrays near substrate steps

Enhanced interchain pi-pi stacking interactions

Doubled average length of GNRs at step edges

Abstract

The influence of substrate steps on the bottom-up synthesis of atomically precise graphene nanoribbons (GNRs) on an Au(111) surface is investigated. A straight surface step is found to promote the assembly of long and compact arrays of polymers with enhanced interchain pi-pi stacking interaction, which creates a steric hindrance effect on cyclodehydrogenation to suppress the H passivation of polymer ends. The modified two-stage growth process results in periodic arrays of GNRs with doubled average length near step edges.