由硫醇分子组成的三元混合膜表面及电子传递性质的研究

采用共吸附法制备了两种三元混合膜,并通过扫描隧道显微镜（STM）、导电原子力（C-AFM）等技术对混合膜表面结构及电子传递性质进行了研究.三元混合膜一种由戊硫醇（C5T）、癸硫醇（C10T）和十六烷基硫醇（C16T）组成,另一种由C5T,C10T和连噻吩二硫醇（BT）组成.在烷基硫醇混合膜中,C10T和C16T插入C5T形成的基底中,且二者出现在组装膜的缺陷处或畴界处,3种分子的导电能力为C5T〉C10T〉C16T.在含BT的混合膜中,BT出现在组装膜的内部,C10T则出现在组装膜的缺陷处以及BT分子周围,3种分子的导电能力为BT〉C5T〉C10T.两种三元混合膜均产生相分离现象,降低组装液中成膜分子的浓度后,相分离的现象有所减轻.由此,可通过调节成膜分子的种类及其在组装液中的浓度,控制其在膜中的含量和表面结构,从而为电子传递提供3种可选择的通路.

Investigation of Surface and Electron Transport Properties of Ternary Mixed Self-assembled Monolayers Composed of Thiols

Two kinds of ternary mixed self-assembled monolayers（SAMs） were prepared by co-adsorption and studied by STM and C-AFM.One was composed of pentanethiols（C5T）,decanethiols（C10T） and hexadecanethiols（C16T）;the other was composed of C5T,C10T and bithiophene-5,5-dithiol（BT）.In the SAMs composed of alkanethiols,C10T and C16T were inserted in the matrix of C5T and appeared at domain boundaries or pit defects.The order of electric conductivity of three components was C5T C10T C16T.In the SAMs containing BT,BT appeared in the interior of SAMs and C10T appeared not only at domain boundaries but also around BT molecules.The order of electric conductivity was BT C5T C10T.However,both of SAMs formed phase-separated domains.And with the decreasing of their concentrations in the solution,the domains of phase-separated regions became smaller.Therefore,contents and structures can be controlled by adjusting the types and the concentrations of thiols in the solution.They offered three optional channels for the electron transport.