•INVITED REVIEWS• September 2019 Vol.62 No.9: 1099–1144 https://doi.org/10.1007/s11426-019-9491-2
Polycyclic aromatic hydrocarbons in the graphene era Xiao-Ye Wang1,2*, Xuelin Yao1 & Klaus Müllen1*
1Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany; 2State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
Recieved February 25, 2019; accepted April 29, 2019; published online June 25, 2019
Polycyclic aromatic hydrocarbons (PAHs) have been the subject of interdisciplinary research in the fields of chemistry, physics, materials science, and biology. Notably, PAHs have drawn increasing attention since the discovery of graphene, which has been regarded as the “wonder” material in the 21st century. Different from semimetallic graphene, nanoscale graphenes, such as graphene nanoribbons and graphene quantum dots, exhibit finite band gaps owing to the quantum confinement, making them attractive semiconductors for next-generation electronic applications. Researches based on PAHs and graphenes have expanded rapidly over the past decade, thereby posing a challenge in conducting a comprehensive review. This study aims to interconnect the fields of PAHs and graphenes, which have mainly been discussed separately. In particular, by selecting representative examples, we explain how these two domains can stimulate each other. We hope that this integrated approach can offer new opportunities and further promote synergistic developments in these fields. polycyclic aromatic hydrocarbon, graphene, graphene nanoribbon, nanographene, graphene quantum dot, carbon materials
Citation: Wang XY, Yao X, Müllen K. Polycyclic aromatic hydrocarbons in the graphene era. Sci China Chem, 2019, 62: 1099–1144, https://doi.org/10.1007/ s11426-019-9491-2
1 Introduction conjugated polymer [3–10]. Although graphene has been predicted to be thermodynamically unstable in early theo- Carbon allotropes and carbon-based materials have recently retical studies [11–13], the groundbreaking work by Geim attracted such attention that one even describes the current and Novoselov et al. [14], after peeling off separate gra- era as the carbon age [1,2]. These materials can appear as phene layers from graphite, has changed the world of ma- discrete particles or bulk materials, and their structures can terials science. be crystalline or amorphous. One can easily understand why Graphene nanoribbons (GNRs) are quasi-one-dimensional “diamonds are a girl’s best friend” but should also consider (1D) graphene cutouts, typically with widths in the range of that soot, a structurally ill-defined product of incomplete 1–100 nm and length/width ratios >10 (Figure 1) [6]. GNRs combustion of carbonaceous matter, is of enormous technical can also be considered as an intermediate between graphene importance, such as in mechanical reinforcement of plastics. and polycyclic aromatic hydrocarbons (PAHs). Comparing Graphite is a carbon allotrope wherein hexagon networks of the electronic features of the quasi-1D GNRs wit