Scanning Tunneling Microscopy Study of a Phenalenyl-Based Singlet Biradical on Graphite

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• 作者：Kai Iketaki ; Kaname Kanai ; Akihiro Shimizu ; Takashi Kubo ; Zhi-Hong Wang ; Yukio Ouchi ; Yasushi Morita ; Kazuhiro Nakasuji ; Kazuhiko Seki
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：January 29, 2009
• 年：2009
• 卷：113
• 期：4
• 页码：1515-1519
• 全文大小：189K
• 年卷期：v.113,no.4(January 29, 2009)
• ISSN：1932-7455

文摘

The adsorption of a phenalenyl-based singlet biradical, 8,16-diphenyl-s-indaceno[1,2,3-cd:5,6,7-c′d′]diphenalene (Ph₂-IDPL), on a highly oriented pyrolytic graphite surface has been studied using scanning tunneling microscopy (STM), tunneling spectroscopy, and ultraviolet photoelectron spectroscopy (UPS) under ultra-high-vacuum conditions. Ph₂-IDPL molecules form a highly ordered monolayer on the graphite surface. The STM images of Ph₂-IDPL monolayers show a strong bias-dependence in the range from −1.8 to +1.6 V. The observed image contrast may be associated with the distortion of the adsorption configuration or structural deformation of the molecules. UPS and tunneling spectroscopy reveal the electronic structure of Ph₂-IDPL. The energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) was determined to be 2.7 eV from the measured peak-to-peak energy difference between the HOMO and LUMO in the tunneling spectrum.