Conformation pre-organization in fluorene-based conjugated polymer for simultaneous enhancement of luminescence and charge mobility

He, Juxin; Du, Luyang; Jiang, Ming-jian; Liu, Linlin; Mo, Yueqi; Xie, Zengqi; Yang, Bing; Ma, Yan

doi:10.1039/c6py01995a

Cited by 10 publications

(2 citation statements)

References 35 publications

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“…In the design of high-performance LCPs, an effective method for suppressing chain aggregation in the solid state is to isolate the backbone chains. − For red and green LCPs, sufficient progress has been made over the last few decades for applications in organic light-emitting diodes (OLEDs), − polymer lasers, , and thin-film transistors . However, blue LCPs that show both long-term stability and high efficiency remain a challenge due to the high energy levels and wide band-gaps. , It has been demonstrated that polyfluorenes (PFs) are promising candidates for blue-light-emitting materials, with the advantages of easy modification, deep blue emission, and high quantum efficiency. ,, However, for PFs in the solid state, a green band emission due to chain aggregation or the ketone at the C-9 position limits commercial application. − Many approaches have been developed to decrease the tendency of aggregation and to avoid this detrimental excimer emission, including substitution of C-9 with bulky groups, − inducing quasi-planar conformation, − copolymerization with steric hindrance, and use of configurations of starburst oligomers. − The planar conformation of PFs (β-phase) can also enhance the charge carrier mobility, spectral purity of the blue emission, and efficiency of the amplified spontaneous emission (ASE). , Compared to the quasi-planar conformation of chains in the robust spiro-bridged ladder-type poly( p -phenylene), the β-phase in PFs stems from an intriguing “planar zigzag” (2 1 helix) chain conformation stabilized by the balance between interchain steric interaction and molecular aggregation in the solid state in thin films, which can induce an enhanced effective conjugation length, close molecular chain packing, and a larger Förster radius for excitation transfer. In our previous work, the β-phase in a bulky polydiarylfluorene was obtained by regulating the interplay between bulky groups using steric hindrance and between alkoxy side chains using van der Waals forces .…”

Section: Introductionmentioning

confidence: 99%

Steric-Hindrance-Functionalized Polydiarylfluorenes: Conformational Behavior, Stabilized Blue Electroluminescence, and Efficient Amplified Spontaneous Emission

Bai

Liu

Han

et al. 2017

ACS Appl. Mater. Interfaces

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Control of the hierarchical molecular organization of polydiarylfluorenes by synthetic strategies is significant for optimizing photophysical properties as well as the performance of light-emitting devices. Herein, for the suppression of molecular aggregation and enhancement of luminescence efficiency, a series of steric units were introduced into polydiarylfluorenes by copolymerization, with the aim of integrating the advantages of the steric-hindrance effect and of the β-phase. Optical and Raman spectroscopies revealed a β-phase conformation for a polymer copolymerized with spiro[fluorene-9,9'-xanthene] (SFX), with photoluminescence (PL) peaks at 454, 482, and 517 nm. Moreover, the morphological stability and electroluminescence (EL) stability were also improved without compromising the performance of the polymer light-emitting diodes (PLEDs). Furthermore, three steric-hindrance-functionalized copolymers showed significantly decreased thresholds for amplified spontaneous emission (E) and enhanced stability following thermal annealing treatment. These results indicate that steric-hindrance functionalization is a superior approach to improve the overall stability and optoelectronic properties for blue-light-emitting π-conjugated polymers.

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Section: Introductionmentioning

confidence: 99%

Steric-Hindrance-Functionalized Polydiarylfluorenes: Conformational Behavior, Stabilized Blue Electroluminescence, and Efficient Amplified Spontaneous Emission

Bai

Liu

Han

et al. 2017

ACS Appl. Mater. Interfaces

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“…As shown in the figures, with the continuous increase in forward‐bias voltage, a gradual rise in the current density was noticed. Of course, this is characteristic of a distinctive diode 55‐58 . Further, their threshold voltages were found to be 5.06 V ( Py 1 ), 5.57 V ( Py 2 ), 5.77 V ( Py 3 ), and 4.04 V ( Py 4 ).…”

Section: Resultsmentioning

confidence: 90%

New cyanopyridine‐based π‐conjugative poly(azomethine)s: Synthesis, characterization and electroluminescence studies

Pilicode

Naik

Nimith

et al. 2020

Polymers for Advanced Techs

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Four new Schiff-base type conjugative polymers (CPs), that is, Py 1-4 carrying a strong electron-withdrawing cyanopyridine scaffold coupled with different electrondonating aromatic/heteroaromatic moieties were synthesized from their respective co-monomers by simple poly-condensation route. They were subjected to structural, thermal, photophysical, and electrochemical characterizations and theoretical investigations in order to identify their suitability in polymer light-emitting diode (PLED) application. All these polymers showed good film-forming ability and exhibited favorable photophysical behaviors with an optical bandgap in the order of 2.54-2.68 eV. Further, their electrochemical data were used to evaluate highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels. Finally, Py 1-4 were successfully employed as blue-light emitter in the construction of new ITO/PEDOT:PSS/ Py 1-4 /Al configured light-emitting diodes (LED), and the fabricated devices demonstrated stable blue electroluminescence behavior endorsing an effective electrons injection in the PLEDs.

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Barbier Hyperbranching Polymerization‐Induced Emission from an AB‐Type Monomer

Sheng

Xiao

et al. 2022

Chemistry A European J

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Luminescent polymer materials have gained considerable research efforts in the past decades and are generally molecular designed by extending the π system of the polymer main chain or by incorporating chromophores into the polymer chain, which suffer from poor solubility, difficult synthesis, or multi-step procedures. Meanwhile, according to the step-growth polymerization theory, synthesis of hyperbranched polymers from an AB-type monomer is still challenging. Herein, we report a one-pot synthesis of nonconjugated luminescent hyperbranched polymer material via Barbier hyperbranching polymerization-induced emission (PIE) from an AB-type monomer. The key step in the realization of the hyperbranched polymer is bi-functionalization of a mono-functional group. Through a Barbier reaction between an organohalide and an ester group in one pot, bifunctionalization of mono-functional ester is realized through two-step nucleophilic additions, resulting in hyperbranched polytriphenylmethanols (HPTPM). Attributed to throughspace conjugation and inter-and intramolecular chargetransfer effects induced by polymer chain, nonconjugated HPTPMs are PIEgens, which are tunable by monomer structure and polymerization time. When all phenyl groups are rotatable, HPTPM is aggregation-induced emission type PIEgen. Whereas, it is aggregation-caused quenching type PIEgen if some phenyl groups are rotation forbidden. Further potential applications of PIEgen are in the fields of explosive detection and artificial light harvesting systems. This work, therefore, expands the monomer library and molecular design library of hyperbranched polymers through "bi-functionalization of mono-functional group" strategy, which eventually expands the preparation library of nonconjugated luminescent polymer materials through one-pot PIE from nonemissive monomer.

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Conformation pre-organization in fluorene-based conjugated polymer for simultaneous enhancement of luminescence and charge mobility

Abstract: The simultaneous enhancement of emission efficiency and charge mobility is realized by poor solvent induced conformation complanation in fluorene-based copolymer.

Cited by 10 publications

References 35 publications

Steric-Hindrance-Functionalized Polydiarylfluorenes: Conformational Behavior, Stabilized Blue Electroluminescence, and Efficient Amplified Spontaneous Emission

Steric-Hindrance-Functionalized Polydiarylfluorenes: Conformational Behavior, Stabilized Blue Electroluminescence, and Efficient Amplified Spontaneous Emission

New cyanopyridine‐based π‐conjugative poly(azomethine)s: Synthesis, characterization and electroluminescence studies

Barbier Hyperbranching Polymerization‐Induced Emission from an AB‐Type Monomer

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