Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany.
J Phys Condens Matter. 2012 Oct 3;24(39):394015. doi: 10.1088/0953-8984/24/39/394015. Epub 2012 Sep 11.
Mixed self-assembled monolayers (SAMs) of alkanethiolates carrying azobenzene chromophores with either a trifluoromethyl or a cyano substituent have been studied. High-resolution x-ray photoelectron spectroscopy proves that the ratio of adsorbed molecules can be arbitrarily adjusted via the molar fractions in solution. As a function of these molar fractions core level shifts are observed which are attributed to local work-function changes. By simulating the electric dipole field distribution, the continuous core level shifts are ascribed to a homogeneous mixture of molecules with different end groups adsorbed on adjacent lattice sites. Near-edge x-ray absorption fine structure measurements reveal formation of well-ordered SAMs. Despite the difference in dipole moment of the end groups, the molecular tilt and twist angles are identical for both single-component SAMs and a 1:1 mixed SAM.
已研究了带有三氟甲基或氰基取代基的偶氮苯生色团的烷硫醇混合自组装单层（SAM）。高分辨率 X 射线光电子能谱证明，通过溶液中的摩尔分数可以任意调节吸附分子的比例。作为这些摩尔分数的函数，观察到芯能级位移，这归因于局部功函数的变化。通过模拟电偶极场分布，连续的芯能级位移归因于具有不同端基的分子的均匀混合物在相邻晶格位置上的吸附。近边 X 射线吸收精细结构测量表明形成了有序的 SAM。尽管端基的偶极矩不同，但两种单一组分 SAM 和 1:1 混合 SAM 的分子倾斜和扭转角是相同的。
