Synthesis and properties of blue light electroluminescent conjugated copolymer based on fluorene and carbazole with an alkyl functional group at the 9-position

Synthesis and photovoltaic device studies of azo‐linked low‐bandgap polymers

“…All the polymers in thin‐film form exhibit absorption maxima red‐shifted by 3 to 18 nm with broadened area in comparison with solution, which can be attributed to enhanced inter‐chain interactions and π–π stacking in the solid state . In solution, P1 and P2 have a broad absorption that extends from 355 to 590 nm with maxima at 440 nm for both, which can be attributed to the π–π * transitions from the fluorene backbone with azo linkage . In comparison to poly(9,9‐dioctylfluorene) and poly[(9,9‐di‐ n ‐octylfluorenyl‐2,7‐diyl)‐ alt ‐4,4′‐azobenzene)], P1 and P2 are red‐shifted by 19 and 23 nm, respectively, in their absorption maxima.…”

Synthesis, characterization, morphological behaviour, and photo- and electroluminescence of highly blue-emitting fluorene-carbazole copolymers with alkyl side-chains of different lengths

“…16,38,39 It has been shown that carbazole units inserted in such a molecular scaffold can signicantly improve the glassystate durability and thermal stability, 40 and blue-emitting alternating uorene-co-carbazole copolymers were described to show excellent thermal stability. [41][42][43] We wish to report herein the synthesis, chemical and structural characterization, as well as morphological and photophysical investigations of a series of highly blue-emitting uorene-co-carbazole-based polymers. In particular, an effort is made to emphasize the structure-property relationship as investigated by the simultaneous use of analytical techniques such as AFM, photoluminescence, DSC and ATG.…”

Synthesis, characterization, photo‐induced alignment, and surface orientation of poly(9,9‐dioctylfluorene‐alt‐azobenzene)s

“…The PFAz s have a broad absorption that extends from 300 to 570 nm with a maxima at 417 nm for P1FAz , 390 nm for P2FAz , and 356 nm for F3FAz , respectively, which are attributed to the π−π* transitions of the fluorene backbone and azobenzene chromophore. In particular, the absorption bands appearing around 375–390 nm, which are clearly evident in the P2FAz and P3FAz spectra, are attributed to the π−π* transition of the conjugated polyfluorene backbone,25, 26 whereas the absorption bands greater than 400 nm shown in P1FAz are due to the π−π* transition of the azobenzene chromophore. This indicates that the copolymers do not have extended conjugation along the polymer main‐chain; therefore, the conjugation could be twisted, due to steric hindrance around the 9‐position dioctyl substituent in the fluorene unit, which prevents a system with fluorene‐to‐fluorene conjugation.…”