Highly efficient polymer blends from a polyfluorene derivative and PVK for LEDs

Photo- and electroluminescence in a series of PPV type terpolymers containing fluorene, thiophene and phenylene units

“…It has been reported that this longer decay is related with oxidation of the polymer chain [ 3,36]. Nevertheless, this hypothesis was not considered in the present case because the 9 positions in the fluorene ring, which is the locus for oxidation is already substituted by alkyl branches.…”

“…For the parent "homopolymers", that is, copolymers without phenylene (LaPPS30-100) and without thiophene (LaPPS30-0) the same route was followed omitting the addition of one of the aldehydes, as described in Refs. [3,28], respectively.…”

“…The chemical linking of monomers in copolymerization or the mixing of polymers in blend fabrication [3] are powerful tools to tune light emission and output yield in LEDs [4,5] and photovoltaic efficiency in solar cells [6,7] apart from other applications.…”

Polyfluorene based blends for white light emission

“…The light emitting polymers poly(9,9-dihexyl-2,7-fluorene) (LaPPS10) poly[(9,9-dihexyl-9H-fluorene-2,7-diyl)-1,2-ethenediyl-1,4-phenylene-1,2-ethenediyl] (LaPPS16), poly(methylmethacrylate-co-methyl-antracenyl methacrylate P(MMA-co-MMAnt) (molar composition of 35:1 of MMA:MMAnt) were synthesized in our laboratory (LaPPS) as described in previous papers [20,22,33]. MEH-PPV was used as purchased from Sigma-Aldrich.…”

“…The addition of this copolymer brings about at least three important consequences: it greatly enhances the optical quality of the films; there is an improvement of the film adhesion on the substrate leading to more flat surfaces; and there is a relative decrease of the contribution of the b-phase still present from the blue emitter LaPPS10 (absorption and emission bands at 432 and 442 nm, respectively). Dilution effect in polymer blends has been observed in several systems leading to a separation of the polymer chains and to the decrease of interchain interactions [33,[45][46][47]. Moreover, the contribution of the b-phase in the JF17 blend seems to be less important than in the JF14, indicating that the improved optical quality produced by the inclusion of the acrylic copolymer is associated to the film morphology.…”