期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:2018
卷号:115
期号:37
页码:9134-9139
DOI:10.1073/pnas.1805357115
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:Polycyclic aromatic hydrocarbon (PAH) molecules are essentially graphene in the subnanometer limit, typically consisting of 50 or fewer atoms. With the addition or removal of a single electron, these molecules can support molecular plasmon (collective) resonances in the visible region of the spectrum. Here, we probe the plasmon dynamics in these quantum systems by measuring the excited-state lifetime of three negatively charged PAH molecules: anthanthrene, benzo[ghi]perylene, and perylene. In contrast to the molecules in their neutral state, these three systems exhibit far more rapid decay dynamics due to the deexcitation of multiple electron–hole pairs through molecular plasmon “dephasing” and vibrational relaxation. This study provides a look into the distinction between collective and single-electron excitation dynamics in the purely quantum limit and introduces a conceptual framework with which to visualize molecular plasmon decay.