Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
Langmuir. 2012 Feb 28;28(8):4016-23. doi: 10.1021/la204340n. Epub 2012 Feb 10.
Cruciform oligo(phenylene ethynylene)s (OPEs) with an extended tetrathiafulvalene (TTF) donor moiety (OPE5-TTF and OPE3-TTF) 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-LUMO 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.
具有扩展的四硫富瓦烯（TTF）给体部分的十字形寡聚（亚苯基乙炔）（OPEs）（OPE5-TTF 和 OPE3-TTF）及其没有共轭取代基的简单类似物（OPE5-S 和 OPE3）被用于在超平整金基底上形成高质量的自组装单层（SAM）。使用导电探针原子力显微镜（CP-AFM）研究了基于这些 SAM 的分子结。TTF 取代基改变了分子轨道能级并降低了 HOMO-LUMO 能隙，与未取代的类似物相比，两种 TTF 十字形 OPE 的电导均增加了 9 倍。通过对单个分子的理论输运计算再现了 SAMs 的电输运性质差异。
