A range of stable emulsions of spherical and rod-like conjugated polymer nanoparticles (CPN) were synthesized via Suzuki−Miyaura cross-coupling reactions of 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester with a number of different dibromoarene monomers in xylene, stabilized in water by the nonionic surfactant, Triton X-102. High molar mass poly(9,9-dioctylfluorene) (PF8), poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PF8BT), poly(9,9-dioctylfluorene-alt-4-sec-butylphenyldiphenylamine) (PF8TAA) and poly(9,9-dioctylfluorene-alt-bithiophene) (PF8T2) emulsions were obtained, at high overall conjugated polymer concentrations (up to 11,000 ppm), in the presence of the palladium complex, (IPr*)PdCl2(TEA) and base, tetraethylammonium hydroxide, in nitrogen atmosphere at 30 °C after 24–48 h. TEM analysis of the PF8 and PF8T2 emulsions revealed regular rod-like structures, up to 200 nm in length with aspect ratios of 4–5. PF8BT and PF8TAA formed spherical particles with diameters of between 20–40 nm in TEM analysis. UV–vis absorption spectra of the PF8 emulsions indicated high levels of ordered β-phase configuration (9–10%) in their respective nanoparticles. Absolute photoluminescence quantum yields (Φ) of 21–25% were recorded for these emulsions.
A series of novel donor-acceptor-donor triads, namely PFTn (n ¼ 0-4), consisting of fluoreneoligothiophenes (FTn) as a donor and perylenediimide (PDI) as an acceptor were synthesized and characterized. The chemically bonded electron donor and acceptor chromophores in the triads were found to be independent. These triads showed a strong intramolecular photo-induced electron transfer (PET) between both chromophores, which gave rise to a quasi-quantitative fluorescence quenching of both PDI and FTn moieties. Distinctively, a reverse energy transfer from the acceptor PDI to the donor FTn induced a strong fluorescence emission from the FTn moieties in the triads PFT3 and PFT4. The PFTn (n ¼ 1-3) triads were proven to undergo an electrochemical oxidative coupling reaction and become electropolymerizable materials to form polymer plastic films (poly(PFTn)), while PFT4 proved to be an electrochemically stable molecule. Experimental sectionGeneral procedure 1 H and 13 C nuclear magnetic resonance (NMR) spectra were recorded on a Bruker AVANCE 300 MHz spectrometer with tetramethylsilane as the internal reference using CDCl 3 as the solvent in all cases. Infrared (IR) spectra were measured on a Perkin-Elmer FTIR spectroscopy spectrum RXI spectrometer as a KBr disc or thin film obtained from electropolymerization. Ultraviolet-visible (UV-vis) spectra were recorded as a dilute solution in spectroscopic grade dichloromethane or as a thin film obtained from electropolymerization on a Perkin-Elmer UV Lambda 25 spectrometer. Photoluminescence spectra and the fluorescence quantum yields (F F ) were recorded with a Perkin-Elmer LS 50B luminescence spectrometer as a dilute solution in
A series of oligoarylenes end-capped with carbazol-N-yl-carbazole (CAr) were synthesized and characterized as color tunable light-emitting materials. Their photophysical, thermal, electrochemical, and electroluminescent properties as non-doped solution processed emitters and hole-transporters for OLEDs were investigated. They exhibited a bright blue to red fluorescence with hole-transporting properties and could form morphologically stable amorphous thin films. Simple structured solutionprocessed CAr-based OLEDs emitted stable colors spanning the entire visible spectrum (blue, light blue, green, yellow and red) with luminance efficiencies up to 13.73 cd A À1 . The CIE coordinates of the emitted colors were (0.67, 0.33) for red, (0.30, 0.61) for green and (0.19, 0.18) for blue, which are close to the pure red, green and blue colors. A solution-processed white OLED fabricated with a mixture of CAr radiated a white light with a luminance efficiency of 1.49 cd A À1 at 4.7 mA cm À2 and CIE coordinates of (0.33, 0.35). † Electronic supplementary information (ESI) available: Synthesis of 1-5, quantum chemical calculation results, multiple scan CV plots, AFM images, EL spectra of the OLEDs and 1 H NMR and 13 C NMR spectra. See
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