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, -phase of poly(9,9-dioctyfluorene) (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 -phase in PFO film obviously enhanced as a result of the addition of a few 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 of the nanostructures of films, of particular interests is that the performance and color purity of polymer light-emitting device can be noticeably enhanced upon the addition of 1-chloronaphthalene additive. These observations highlight the importance of control the nanostructures of emissive layer, and demonstrate the addition of a few volume ratio of high boiling point additive can be a promising strategy to attain high performance polymer light emitting diodes.

The Importance of Microstructure in Determining Polaron Generation Yield in Poly(9,9-dioctylfluorene)

“…13 A similar argument may equally apply to PFO. However, there is much variation in the hole and electron mobilities of PFO quoted in the literature spanning several orders of magnitude and comparatively few reports of electron mobilities, 32,[77][78][79][80][81] thus making reliable assessment difficult. This noted, reports where both charge carrier mobilities were determined, suggest a large mismatch between hole and electron mobilities.…”

“…This noted, reports where both charge carrier mobilities were determined, suggest a large mismatch between hole and electron mobilities. [80][81][82] Moreover, if there are differences in the mobilities of the same charge carrier type between glassy and β-phases, this may act to further increase the likelihood of spatial separation of charges at the glassy/β-phase interface.…”

An Easy Approach to Control β-Phase Formation in PFO Films for Optimized Emission Properties

“…Compared to the inorganic opponent, these materials can be tailored through chemical structure modification or conformation control during processing. Among all the conjugated polymers, poly(9,9-dioctylfluorene) (PFO) and its derivatives are one class of the most attractive candidates for light-emitting diodes [ 1 , 2 , 3 , 4 ] and lasers [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ] as a blue-emitter. Research on PFO was mainly focused on the luminance efficiency increase and color purity of the PFO light emitting diode (LED) and the threshold reduction of PFO laser.…”

Discovery and structure characteristics of the intermediate-state conformation of poly(9,9-dioctylfluorene) (PFO) in the dynamic process of conformation transformation and its effects on carrier mobility

“…Conversely, a remarkably high content of b conformation will prompt PFO chains to form macroscopic aggregations, which can result in a rough lm surface and is unsuitable for device fabrication and device performance optimization. 38,39 Therefore, both good lmforming and high carrier mobility performance are key to fabricate excellent polymer photoelectric devices. This research was performed to explore this issue.…”