In Situ STM Imaging of the Structures of Pentacene Molecules Adsorbed on Au(111)

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/28308

Title:	In Situ STM Imaging of the Structures of Pentacene Molecules Adsorbed on Au(111)
Authors:	Pong,I;Yau,S;Huang,PY;Chen,MC;Hu,TS;Yang,YC;Lee,YL
Contributors:	中央大學
Keywords:	SCANNING-TUNNELING-MICROSCOPY;X-RAY-SCATTERING;BARRIER-HEIGHT;SOLAR-CELLS;SURFACES;ADLAYERS;FULLERENES;ADSORPTION;MONOLAYER;SUBSTRATE
Date:	2009
Issue Date:	2010-06-29 19:45:52 (UTC+8)
Publisher:	化學研究所
Abstract:	In situ scanning tunneling microscope (STM) was used to examine the spatial structures of pentacene molecules adsorbed onto a Au(111) single-crystal electrode from a benzene dosing solution containing 16-400 mu M pentacene. Molecular-resolution STM imaging conducted in 0.1 M HClO4 revealed highly ordered pentacene structures of (root 31 x root 31)R8.9 degrees (3 x 10), (root 31 x 10), and (root 7 x 2 root 7)R19.1 degrees adsorbed on the reconstructed Au(111) electrode dosed with different pentacene solutions. These pentacene structures and the reconstructed Au(111) substrate were stable between 0.2 anti 0.8 V [vs reversible hydrogen electrode, RHE]. Increasing the potential to E > 0.8 V lifted the reconstructed Au(111) surface and disrupted the ordered pentacene adlattices simultaneously. Ordered pentacene structures could be restored by applying potentials negative enough to reinforce the reconstructed Au(111). At potentials negative of 0.2 V, the adsorption of protons became increasingly important to displace adsorbed pentacene admolecules. Although the reconstructed Au(111) structure was not essential to produce ordered pentacene adlayers, it seemed to help the adsorption of pentacene molecules in a long-range ordered pattern. At room temperature (25 degrees C), similar to 100 pentacene molecules seen in STM images could rotate and align themselves to a neighboring domain in 10 s, suggesting that pentacene admolecules could be mobile on Au(111) under the STM imaging conditions of -150 mV in bias voltage and 1 nA in feedback current.
Relation:	LANGMUIR
Appears in Collections:	[Graduate Institute of Chemistry] journal & Dissertation

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