For the improvement of the electron transporting property of poly(9,9-di-n-octylfluorene) (PFO) as a conventional PLED material, well-defined triblock copolymers of PFO [Number-average molecular weight (Mn
) ≈ 10000] with different chain length polystyrene (PSt) (Mn
≈ 1000, 2000, and 3000) were synthesized via a combined synthesis strategy of Suzuki-Miyaura reaction, atom transfer radical polymerization (ATRP), and Steglich coupling reaction. Electron only (EO) devices for homopolymer and triblock copolymers were fabricated by a solution process. It was demonstrated that triblock copolymer (Mn,PSt
≈ 2000) after annealing exhibited the highest electron mobility. Thermal, optical, electrochemical and morphological properties were investigated severally and revealed that the microphase separated structure was formed in block copolymers (Mn,PSt
≈ 2000, and 3000) after annealing, and the introduction of PSt raised the glass transition temperature (Tg
) and deepened the LUMO level.
Cyclic triphenylamine (TPA) oligomers synthesized by C–N coupling were found to be capable of complexing with fullerenes, and the applications in optoelectronic devices were investigated by using the fabricated ITO/PEDOT:PSS/active layer/Au devices.
A method for deforming fractals from complex dynamics is proposed. Firstly, an elementary fractal transfiguration model of complex quadratic dynamics in the form of a six-parameter family is presented. Secondly, a two-dimensional extension factor, also including six control parameters, is constructed. Finally, a transfiguration algorithm is put forward, which begins with an iteration of the fractal transfiguration model for computation of the periodicities of all discrete points in the given complex plane and then exerts a 2D extension factor on every point to transfer them while keeping their periodicities unchanged. Experimental results demonstrate that our fractal deformation algorithm is simple, intuitive, foreseeable and easy to control. It is hoped that our investigation would result in new perspectives for the deformation of other deterministic fractals as well.
Poly[9,9-bis(2,4-octanedionyl)-9′,9′-di-n-octyl[2,2′-bi-9H-fluorene]-7,7′-diyl] (PFOA) was prepared with a β-diketone structure incorporated in the side chain and the optimal octyl length remained. Compared with poly(9,9-di-n-octylfluorene) (PFO) with a similar degree of polymerization, we found that the introduction of β-diketone brought about superior fluorescent, electrochemical and electron transporting properties, which suggested improved color stability and electron mobility.
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