The structures of novel organic molecule consisting of pentacene and thiophene on Au(111)

• Main Authors: Yi-Fen Peng, 彭貽芬
• Other Authors: Shueh-Lin Yau
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/4s44dh

碩士 === 國立中央大學 === 化學研究所 === 97 === In situ scanning tunneling microscope (STM) was used to examine the spatial structures of pentacene molecules adsorbed onto a Au(111) electrode from a benzene dosing solution containing 16 - 400 μM pentacene. Molecular-resolution STM imaging conducted in 0.1 M HClO4 revealed highly ordered pentacene structures of (?31 ? ?31), (3 ? 10), (?31 ? 10), and (?7 ? 2?7) adsorbed on the reconstructed Au(111) electrode dosed with different pentacene solutions. These pentacene structures were stable between 0.2 and 0.8 V [vs. 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?C), ~ one hundred 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. The thiophene derivatives DB-DTT and DNS-DTT on Au(111) electrode were examined with in situ STM and CV in 0.1 M HClO4.While DB-DTT arranges in well-ordered (√13 × 2√19) and (9 × √3) structures. These two structures did not change by higher dosage.The adlayer of DNS-DTT have two well-order structures, (15 × √3) and (12 × 2√3) as coverages 0.067 and 0.042.