変調された電場による電極を用いない有機材料中の伝導度測定の原理と応用

抄録

Recently a variety of supra-molecular architectures have been successfully reported based on the strong non-covalent interactions of conjugated molecules, and their feasibility for practical electric materials has been investigated vigorously. The most important parameter determining the performance of electronic devices based on the conjugated supra-molecular architectures is the mobility of charge carriers, however the non-covalent architectures exhibit extremely wide variety of the stacking structures of the component molecules, leading to the several orders of magnitude difference in the value of mobility. The non-covalent interactions to promote supra-molecular architectures are intrinsically anisotropic, thus the value along each axis of a structure gives important insights into not only highly conducting pathways in the materials but also design strategies of the architectures for the optimized electric properties. Conventional techniques of mobility measurements, however, have not been suitable to reveal the anisotropic conductivity because of the difficulty of the electrode fabrication onto the architectures along a variety of axes. The non-contact measurement technique of electric conductivity using a microwave resonant cavity (TRMC) system has been developed, and successfully applied to estimate the value of mobility along each axis of solid supra-molecular architectures. In the present paper, we report the anisotropic nature of electric conduction in several supra-molecular architectures, as well as the direct observation of space-resolved nm-scaled mobility in the bulk solids and interfaces of conjugated molecular materials.