On-surface synthesis and characterization of individual polyacetylene chains

Shiyong Wang; Qiang Sun; Oliver Gröning; Roland Widmer; Carlo A Pignedoli; Liangliang Cai; Xin Yu; Bingkai Yuan; Can Li; Huanxin Ju; Junfa Zhu; Pascal Ruffieux; Roman Fasel; Wei Xu

doi:10.1038/s41557-019-0316-8

On-surface synthesis and characterization of individual polyacetylene chains

Nat Chem. 2019 Oct;11(10):924-930. doi: 10.1038/s41557-019-0316-8. Epub 2019 Sep 2.

Authors

Shiyong Wang^{1

2}, Qiang Sun³, Oliver Gröning¹, Roland Widmer¹, Carlo A Pignedoli¹, Liangliang Cai³, Xin Yu³, Bingkai Yuan², Can Li², Huanxin Ju⁴, Junfa Zhu⁴, Pascal Ruffieux¹, Roman Fasel^{5

6}, Wei Xu⁷

Affiliations

¹ Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
² Key Laboratory of Artificial Structures and Quantum Control, School of physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China.
³ Interdisciplinary Materials Research Center, College of Materials Science and Engineering, Tongji University, Shanghai, China.
⁴ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.
⁵ Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland. roman.fasel@empa.ch.
⁶ Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland. roman.fasel@empa.ch.
⁷ Interdisciplinary Materials Research Center, College of Materials Science and Engineering, Tongji University, Shanghai, China. xuwei@tongji.edu.cn.

PMID: 31477850
DOI: 10.1038/s41557-019-0316-8

Abstract

Polyacetylene (PA) comprises one-dimensional chains of sp²-hybridized carbon atoms that may take a cis or trans configuration. Owing to its simple chemical structure and exceptional electronic properties, PA is an ideal system to understand the nature of charge transport in conducting polymers. Here, we report the on-surface synthesis of both cis- and trans-PA chains and their atomic-scale characterization. The structure of individual PA chains was imaged by non-contact atomic force microscopy, which confirmed the formation of PA by resolving single chemical bond units. Angle-resolved photoemission spectroscopy suggests a semiconductor-to-metal transition through doping-induced suppression of the Peierls bond alternation of trans-PA on Cu(110). Electronically decoupled trans-PAs exhibit a band gap of 2.4 eV following copper oxide intercalation. Our study provides a platform for studying individual PA chains in real and reciprocal space, which may be further extended to study the intrinsic properties of non-linear excitons in conducting polymers.