Structurally defined nanographene-containing conjugated polymers for high quality dispersions and optoelectronic applications

Abstract

Novel conjugated polymers such as poly(phenylene-fluorene) P1 and poly(triphenylbenzene-fluorene) P2with hexaphenylbenzene (HPB) as a pending side group were prepared by Suzuki coupling using the dibromo monomers M1 and M2 with 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester, respectively. The HPB moiety of P1 and P2 can be oxidatively cyclodehydrogenated with FeCl 3 in nitromethane, yielding polymers P3 and P4 with hexa-peri-hexabenzocoronene (i.e., nanographene) units.The cyclodehydrogenation of nanographene-containing polymers was confirmed by FT-IR spectroscopy. In addition, X-ray powder diffraction of both P3 and P4 revealed a polymer interlayer spacing of 1.3 nm being dominated by the nanographenes. The glass transition temperatures (T g s) of P1 and P2 were 202°C and 235°C, respectively, while both P3 and P4 with nanographenes possessed T g s higher than 300°C. Compared to P3, P4 with a triphenylbenzene moiety in its backbone can be well dispersed without aggregation in N-cyclohexyl-2-pyrrolidone (CHP), as confirmed by UV-Vis spectroscopy, photoluminescence spectroscopy (PL) and photoluminescence-excitation (PLE) maps.Scheme 1 The synthesis of HPB-containing monomers M1 and M2 as well as conjugated polymers P1 and P2. PaperPolymer Chemistry 6212 | Polym. Chem., 2016, 7, 6211-6219This journal is

Tuning the optical properties of ethynylene triptycene‐based copolymers via oxidation of their alkyne groups into α‐diketones

“…It is noteworthy that conjugated polymers are employed in many potential optoelectronic applications, such as, field‐effect transistors, electroluminescent devices, solar cells, and sensors . Among others, polymer light‐emitting diodes (PLEDs) from polyfluorene (PF) derivatives have been widely studied because they possess many advantages, like, high quantum yields, excellent processability in different solvents, and good charge transport properties . However, ethynylene units proved to be efficient building blocks in the polymer structures because they can undergo further functionalization reactions resulting in polymers with enhanced properties …”

Direct synthesis of polyaromatic chains of tribenzopentaphene copolymers through cyclodehydrogenation of their poly‐tetraphenylbenzene precursors

“…Figure depicts the FT‐IR absorption spectra of polymers 4a and 5a . It could be easily noticed that the broad peak at 4047 cm −1 in 4a , and which is characteristic of the carbon–carbon free rotation in biphenyl groups has completely disappeared in the target polymer 5a , therefore, indicating the full aromatization of the tetraphenyl benzene groups into the rigid TBP core. Similarly, polymer 4a reveals IR absorption signals at 3055 cm −1 , typical for aromatic CH stretching vibrations .…”

“…It is noteworthy that opto‐ and electroactive polymers mainly consist of fused heterocyclic building blocks and their derivatives, whereas less attention has been drawn to poly‐PAHs whose lack of effective synthesis and scarce solubility represent the utmost challenges. Recently, more interest has been drawn in making polyphenylenes and triphenylene‐based polymers …”

Synthesis of Well‐Defined Poly(norbornene) Containing Carbon Nanodots by Controlled ROMP

“…However, the strong π–π stacking owing to the planar structure results in poor solubility in organic solvents, which can be overcome by incorporating long and branched alkyl‐chains or breaking the planarity of the PAH . Another method to improve the solubility is to incorporate the PAH into a polymer backbone as a pendant group, but an additional monomer‐bearing solubilizing group is necessary …”

“…14 Another method to improve the solubility is to incorporate the PAH into a polymer backbone as a pendant group, but an additional monomer-bearing solubilizing group is necessary. 15 The ROMP of norbornene (NB) derivatives has become a powerful tool to synthesize complex macromolecules including block copolymers, [16][17][18] graft-polymers, [19][20][21] and dendronized polymers. [22][23][24][25][26] Despite the versatility of the ROMP, its synthetic application for the production of polymers with PAH moieties has been rarely investigated.…”