Photoexcited State Confinement in Two-Dimensional Crystalline Anthracene Monolayer at Room Temperature

Masahiro Shibuta, Naoyuki Hirata, Toyoaki Eguchi, Atsushi Nakajima

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Organic thin film electronics place a high demand on bottom-up technology to form a two-dimensionally (2D) functional unit consisting of a single molecular crystalline layer bound to a layered structure. As the strong interaction between a substrate and molecules makes it difficult to evaluate the electronic properties of organic films, the nature of electronic excited states has not been elucidated. Here, we study a 2D crystalline anthracene monolayer electronically decoupled by alkanethiolates on a gold substrate using scanning tunneling microscopy and time-resolved two-photon photoemission spectroscopy and unravel the geometric/electronic structures and excited electron dynamics. Our data reveal that dispersive 2D excited electrons on the surface can be highly coupled with an annihilation of nondispersive excitons that facilitate electron emission with vibronic interaction. Our results provide a fundamental framework for understanding photoexcited anthracene monolayer and show how the coupling between dispersive and nondispersive excited states may assist charge separation in crystalline molecular layers.

Original languageEnglish
Pages (from-to)4307-4314
Number of pages8
JournalACS Nano
Volume11
Issue number4
DOIs
Publication statusPublished - 2017 Apr 25

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Keywords

  • electron dynamics
  • excitons
  • organic devices
  • self-assembled monolayer
  • two-dimensional crystal
  • two-photon photoemission

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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