The morphology and photoelectronic properties of poly(9,9′‐dioctylfluorene)/ethyl‐cyanoethyl cellulose blends

Abstract

AbstractThe morphology and photoelectronic properties of blend films of poly(9,9′‐dioctylfluorine) (PF) and ethyl–cyanoethyl cellulose [(E‐CE)C] were investigated. It was found that the morphology of the blends was changed with the blend composition. The lateral phase separation was observed in submicron scale, and a nanoscale vertical phase separation occurred with enrichment of the (E‐CE)C at the surface of the blend films. The photoluminescent spectra of the blend films are blue‐shifted with the increase of the (E‐CE)C. The photoelectronic properties of the blends varied with the morphology of the blends. In the electroluminescent device, the turn‐on voltage was almost identical for the device with 50% or above 50 wt % PF in blend films and markedly improved for the device with only 25 wt % PF. The external quantum efficiency of the device fabricated with 75% PF is the highest among the device fabricated with the PF/(E‐CE)C blend films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007