Detection of Light Emission from (S)-PTCDI Molecules Adsorbed on Au(111) and NiAl(110) Surfaces Induced by a Scanning Tunneling Microscope

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• 作者：Pawel Krukowski ; Takuro Tsuzuki ; Yuto Minagawa ; Nami Yajima ; Songpol Chaunchaiyakul ; Megumi Akai-Kasaya ; Akira Saito ; Yusuke Miyake ; Mitsuhiro Katayama ; Yuji Kuwahara
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 25, 2016
• 年：2016
• 卷：120
• 期：7
• 页码：3964-3977
• 全文大小：1022K
• ISSN：1932-7455

文摘

We report the suppression and enhancement of light emission from (S)-PTCDI molecules (the S-type enantiomer of the chiral binaphthylene-perylenebiscarboxydiimide dimer) adsorbed on Au(111) and NiAl(110) surfaces, which were investigated by scanning tunneling microscopy-induced luminescence (STM-LE). We deposited (S)-PTCDI molecules on a Au(111) surface maintained at low (150 ± 20 K) and elevated (355 ± 20 K) temperatures. At the low temperature, we observed preferential adsorption at face-centered cubic elbows of the herringbone reconstruction and the formation of a quasi-ordered molecular layer with increasing coverage. At the elevated temperature, (S)-PTCDI molecules formed highly ordered domains consisting of self-assembled molecules with positional and orientation order. We observed four different phases of ordered domains with different molecular arrangements and orientations on the Au(111) surface. In contrast to the Au(111) surface, the formation of small molecular clusters at random positions was observed on a NiAl(110) surface at the elevated temperature. We observed the strong enhancement of light emission when the STM tip was placed above the (S)-PTCDI clusters adsorbed on the NiAl(110) surface at bias voltages of 2.4 V and above. We discuss the molecular origin of the light detected above the molecular clusters grown on the NiAl(110) surface.