Alternating-current light-emitting devices based on conjugated polymers

Abstract

Most polymer electroluminescent devices to date are represented as tunnel diodes and operate under direct-current (dc) driving field. Here we report the fabrication of symmetrically configured alternating-current (ac) light-emitting (SCALE) devices based on conjugated polymers. The new devices consist of an emissive polymer layer sandwiched between two redox polymer layers. This configuration enables the SCALE devices to work under both forward and reverse dc bias as well as in ac modes. The nearly ohmic electrode/redox polymer contacts improve the charge injection efficiency significantly and make the SCALE device operation insensitive to electrode work functions. Symmetric operation supports the key role of redox polymer/emissive polymer interface states.