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Multicolor emission from non-conjugated polymers based on a single switchable boron chromophore
摘要： Multicolor emissive and responsive materials are highly attractive due to their potential applications in various fields, and polymers are preferred for their good processability and high stability. Herein, we report a series of new polymers based on a methacrylate monomer containing a switchable boron chromophore. In spite of the unconjugated nature, interestingly, the homopolymers from this monomer display rare multicolor fluorescence in solution that is highly dependent on the degree of polymerization (DP). With an ascending DP, the local concentration of the chromophore increases, leading to a higher propensity for switching the blue emitting tricoordinate boron chromophore to the red emitting tetracoordinate one. The homopolymers also display temperature and solvent-dependent emission colour change. Furthermore, pure white-light emission could be achieved in various solvents by precisely tuning the homopolymer molecular weight, or in films/solid state by copolymerizing the emissive boron monomer with non-emissive monomers in an appropriate ratio.
关键词： Multi-responsiveness,Non-conjugated Polymer,Single Chromophore,White Light Emission,Multicolor Emission
更新于2025-09-10 09:29:36
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Synthesis, characterization, and self-assembly behavior of poly(m-phenylene)s with terthiophene and chiral side chains
摘要： A series of novel poly(m-phenylene)s with terthiophene and/or chiral side chains have been developed to investigate the correlation between poly(m-phenylene) polymer structure and self-assembly behaviors. As a result of circular dichroism spectroscopy, a poly(m-phenylene) that alternately had terthiophene and chiral side chains exhibited the clear Cotton effect in THF, THF/methanol, and THF/acetonitrile conditions, indicating that the defined nanostructure was successfully formed by efficiently using the two interactions between side chains even in the good solvent condition. On the other hand, poly(m-phenylene)s with an irregularly sequence of terthiophene and chiral side chains did not have a capability to form the nanostructure regardless of solvent condition. These results demonstrated that an efficient usage of side chain interactions based on an alternating polymer structure was important for the formation of self-assembled nanostructure in poly(m-phenylene)s.
关键词： Self-assembly,Circular dichroism,Conjugated polymer,Polyphenylene
更新于2025-09-10 09:29:36
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Magnetic field effect on polaron recombination in conjugated polymers
摘要： By using the one-dimensional tight-binding model, we theoretically investigate the effect of magnetic field on the collision of the oppositely charged polarons with their spin antiparallel in cis-polyacetylene. We adopt the non-adiabatic approach to simulate the dynamical evolution of polaron spin. Under the effect of electric field with a moderate strength, the polarons initially localized at the chain-end of polyacetylene move towards each other. During the collision process, an obvious spin precession is obtained, and the precession period is found to be inversely proportional to the strength of magnetic field. While after including electron-electron interaction in form of Hubbard model, the period is no longer constant. With the decrease of distance between the oppositely charged polarons, the precession of their spin slows down. We also find that there is a critical value of electron-electron interaction strength, over which the spin precession of polaron disappears. In addition, we demonstrate that under the effect of magnetic field, the polarons could recombine or pass through each other to form the singlet exciton, rather than be dissociated after collision between them with the strong electron-electron interaction, and then the electroluminescence efficiency of organic optoelectronic devices is improved.
关键词： polaron,conjugated polymer,Zeeman effect,electron-electron interaction,spin precession,magneto-electroluminescence
更新于2025-09-10 09:29:36
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Ultrapure Films of Polythiophene Derivatives are Born on a Substrate by Liquid Flow
摘要： Almost all ?lms of conjugated polymers are composed of mixtures of two di?erent structures called H- or J-aggregates, which are side-by-side and head-to-tail structures, respectively, between polymer chains. The mixture of H- and J-aggregates is responsible for the mixed optical and/or electrical properties of a conjugated polymer ?lm. If a highly puri?ed conjugated polymer ?lm composed of only a single species of aggregate was obtained, its properties would enable the realization of new soft electronics, such as ?exible solar cells, wearable sensors, and arti?cial skin. However, there have been no reports on a method to prepare such a highly puri?ed polymer ?lm so far. Here, we show a facile method to obtain an ultrapure 99.8% H-aggregate polymer ?lm by dropping a solution of poly(3-hexylthiophene) (P3HT) on a substrate at room temperature, inspired by the co?ee-ring e?ect.According to contact angle measurements, photoluminescence and Raman spectroscopy, and X-ray di?raction, a critical step for achieving the ultrapure H-aggregate ?lm was a two-step drying process of the polymer solution droplet on a speci?c substrate. The pinning of the droplet caused this drying process and yielded a ?ow-induced extension of the P3HT chains on the substrate, followed by the formation of ultrapure H-aggregates. We also found a 6-fold enhancement in carrier density using the ultrapure (99.8%) H-aggregate P3HT ?lm. Furthermore, ?ve conjugated polymers of polythiophene derivatives, used as state-of-the-art polymer solar cells, revealed the same trends to ultrapure H-aggregates, whose structure enhances performance of solar cell. The proposed method could provide a new approach to make solution-processable ?lms for next-generation soft and ?exible electronics.
关键词： π-conjugated polymer,contact angle,aggregate,soft electronics,co?ee ring
更新于2025-09-10 09:29:36
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Synthesis and Characterization of novel Thiophene and Carbazole-based Polymers – Optical and Electrochemical Characterization
摘要： A donor/acceptor series of carbazole copolymers, composed of alternating 2,7-linked 3,6-difluoro-9-(1-octyl-nonyl)-carbazole units and bithiophene repeated units [P1], 5,7-bis(5-bromothiophen-2-yl)-2,3-bis(4-(2-ethylhexyloxy) phenyl) thieno[3,4-b]pyrazine repeated units [P2] and bithiophene mixed with thieno[3,4-b]pyrazine repeated units [P3] have been prepared following Suzuki polymerisation procedures. The route of synthesis and characterisation techniques of this novel class of materials, together with their photo-physical and electrochemical properties are presented in this study. The polymers were characterised by 1H NMR, 13C NMR and Elemental Analysis. Molecular weights were estimated using gel permeation chromatography (GPC). The thermal stability behaviour for polymers was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electronic and photo-physical properties were investigated by use of cyclic voltammetry (CV) and UV-Vis spectroscopy, respectively.
关键词： Conjugated polymer,Organic solar cell,Band gap
更新于2025-09-04 15:30:14