Ng Tse Nga, Silveira William R, Marohn John A
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA.
Phys Rev Lett. 2007 Feb 9;98(6):066101. doi: 10.1103/PhysRevLett.98.066101. Epub 2007 Feb 5.
In order to determine energetic disorder's role in facilitating charge injection from gold into a molecularly doped polymer, we have examined the dependence of current on the local electric field, measured using electric force microscopy, at temperatures ranging from 250 to 330 K. From these data we infer, in a single experiment, the temperature dependence of the main factors governing the injection current: the electric-field induced lowering of the image-potential barrier, the interfacial charge density, and the mobility. In this system, the Schottky effect is anomolously large, and the interfacial charge density is larger than expected and strikingly non-Arhennius. Our analysis indicates that these effects are all a consequence of the Gaussian density of states in the organic.
为了确定能量无序在促进电荷从金注入分子掺杂聚合物中所起的作用，我们研究了在250至330 K温度范围内，利用静电力显微镜测量的电流对局部电场的依赖性。从这些数据中，我们在单个实验中推断出控制注入电流的主要因素的温度依赖性：电场引起的镜像势垒降低、界面电荷密度和迁移率。在这个系统中，肖特基效应异常大，界面电荷密度比预期的大，并且明显不符合阿累尼乌斯定律。我们的分析表明，这些效应都是有机物中高斯态密度的结果。
