Molecular Junctions Based on SAMs of Cruciform Oligo(phenylene ethynylene)s

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• 作者：Zhongming Wei ; Tao Li ; Karsten Jennum ; Marco Santella ; Nicolas Bovet ; Wenping Hu ; Mogens Br酶ndsted Nielsen ; Thomas Bj酶rnholm ; Gemma C. Solomon ; Bo W. Laursen ; Kasper N酶rgaard
• 刊名：Langmuir
• 出版年：2012
• 出版时间：February 28, 2012
• 年：2012
• 卷：28
• 期：8
• 页码：4016-4023
• 全文大小：460K
• 年卷期：v.28,no.8(February 28, 2012)
• ISSN：1520-5827

文摘

Cruciform oligo(phenylene ethynylene)s (OPEs) with an extended tetrathiafulvalene (TTF) donor moiety (OPE5鈥揟TF and OPE3鈥揟TF) and their simple analogues (OPE5-S and OPE3) without conjugated substituents were used to form high-quality self-assembled monolayers (SAMs) on ultraflat gold substrates. Molecular junctions based on these SAMs were investigated using conducting-probe atomic force microscopy (CP-AFM). The TTF substituent changes the molecular orbital energy levels and decreases the HOMO鈥揕UMO energy gap, resulting in a 9-fold increase in conductance for both TTF cruciform OPEs compared to the unsubstituted analogues. The difference in electrical transport properties of the SAMs was reproduced by the theoretical transport calculations for the single molecules.