Electronic and Ionic Electric Field Screening and Persistent Built‐In Electric Field in Carbon Nanotube/PCBM Films

Abstract

The application of carbon nanotubes in electronic devices requires detailed knowledge of their electrical properties. Herein, the long‐lasting electric field‐induced polarization of single‐wall carbon nanotube (SWCNT) networks is demonstrated. It is found that electric voltage applied to the films of SWCNTs and their blends with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) creates persistent polarization that partly screens the external electric field and creates a built‐in electric field of the opposite direction remaining for several days. The built‐in electric field has caused the appearance of an open‐circuit photovoltage and a short‐circuit photocurrent under the sample illumination at zero applied voltage. The built‐in field showed a clearly bicomponential decay. The short tens of microseconds component is attributed to the electronic polarization, while the long‐lived component, which decreases at low temperatures, is attributed to the temperature‐assisted motion of ions.