Polyfluorene-Polytriarylamine Block Copolymer as an Additive for Electroluminescent Devices Based on Polymer Blends

Jahanfar, Mehdi; Tan, Ying; Tsuchiya, Kousuke; Shimomura, Takeshi; Ogino, Kenji

doi:10.4236/ojopm.2013.32007

Cited by 2 publications

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References 20 publications

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“…However, some major drawbacks for their use are their high ionization potential associated with low photoluminescence (PL) efficiency, their rather large band gap and facile photochemical degradation [ 12 – 13 ]. Different strategies have been employed in view to reduce these undesirable effects, e.g., the synthesis of copolymers [ 14 – 17 ], block copolymers [ 18 ], the introduction of donor (D) and acceptor (A) moieties [ 19 – 21 ], or bulky substituents at the C-9 position of the fluorene units [ 22 – 24 ], incorporating PF moieties into zeolites [ 25 ], nanochannels [ 26 ], or by wrapping with amylose [ 27 ]. The past decade has witnessed remarkable innovations and progress in polymer science, including the field of supramolecular science as a complementary field, which offers great opportunity for new concepts, new materials with unique properties, and novel practical applications.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

Farcas¹,

Tregnago²,

Resmeriță³

et al. 2015

Beilstein J. Org. Chem.

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SummaryTwo alternating polyfluorene polyrotaxanes (3·TM-βCD and 3·TM-γCD) have been synthesized by the coupling of 2,7-dibromofluorene encapsulated into 2,3,6-tri-O-methyl-β- or γ-cyclodextrin (TM-βCD, TM-γCD) cavities with 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester. Their optical, electrochemical and morphological properties have been evaluated and compared to those of the non-rotaxane counterpart 3. The influence of TM-βCD or TM-γCD encapsulation on the thermal stability, solubility in common organic solvents, film forming ability was also investigated. Polyrotaxane 3·TM-βCD exhibits a hypsochromic shift, while 3·TM-γCD displays a bathochromic with respect to the non-rotaxane 3 counterpart. For the diluted CHCl3 solutions the fluorescence lifetimes of all compounds follow a mono-exponential decay with a time constant of ≈0.6 ns. At higher concentration the fluorescence decay remains mono-exponential for 3·TM-βCD and polymers 3, with a lifetime τ = 0.7 ns and 0.8 ns, whereas the 3·TM-γCD polyrotaxane shows a bi-exponential decay consisting of a main component (with a weight of 98% of the total luminescence) with a relatively short decay constant of τ1 = 0.7 ns and a minor component with a longer lifetime of τ2 = 5.4 ns (2%). The electrochemical band gap (ΔE g ) of 3·TM-βCD polyrotaxane is smaller than that of 3·TM-γCD and 3, respectively. The lower ΔE g value for 3·TM-βCD suggests that the encapsulation has a greater effect on the reduction process, which affects the LUMO energy level value. Based on AFM analysis, 3·TM-βCD and 3·TM-γCD polyrotaxane compounds exhibit a granular morphology with lower dispersity and smaller roughness exponent of the film surfaces in comparison with those of the neat copolymer 3.

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