Charge transport in white light-emitting polymers

摘要

The charge transport in white light-emitting polymers was investigated using hole-only devices of a series of copolymers. The series consists of three spirobifluorene copolymers with a common backbone. The polymers contain an increasing number of dyes that are included into the backbone to achieve white light emission. Because the dyes have different band gaps than the backbone, it is expected that they will hamper the charge transport in the polymer since they will result in electron traps or hole traps, or both. In this experiment we demonstrate that the dyes in the polymers under investigation have no influence on the hole transport. We therefore conclude that the dyes have their HOMO levels aligned and are thus likely to function as electron traps.