title: Improving efficiency and color purity of poly(9,9-dioctylfluorene) through addition of a high boiling-point solvent of 1-chloronaphthalene.
abstract: In this work, the β-phase of poly(9,9-dioctylfluorene) (PFO) was used as a probe to study the effects of the addition of a high boiling-point solvent of 1-chloronaphthalene on the nanostructures and electroluminescence of PFO films. Both absorption and photoluminescence spectra showed that the content of the β-phase in PFO film was obviously enhanced as a result of the addition of a small amount of 1-chloronaphthalene into the processing solvent of p-xylenes. Apparently rougher morphology associated with the effectively enhanced ordering of polymer chains across the entire film was observed for films processed from p-xylene solutions consisting of a certain amount of 1-chloronaphthalene, as revealed by atomic force microscopy and grazing incidence x-ray diffraction measurements. In addition to the effects on the nanostructures of films, of particular interest is that the performance and color purity of polymer light-emitting devices can be noticeably enhanced upon the addition of 1-chloronaphthalene. These observations highlight the importance of controlling the nanostructures of the emissive layer, and demonstrate that the addition of a low volume ratio of high boiling-point additive can be a promising strategy to attain high-performance polymer light-emitting diodes.
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices, State Key Lab of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Junfei
authors.initials: J
authors.lastname: Liang
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.lastname: Sen Zhao
authors.forename: Lei
authors.initials: L
authors.lastname: Ying
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Junbiao
authors.initials: J
authors.lastname: Peng
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao