A Low Band Gap Polymer Based on Selenophene and Benzobis(thiadiazole)

Donor-Acceptor-Type Copolymers Based on 3,4-Propylenedioxy-thiophene and 5,6-Difluorobenzotriazole: Synthesis and Electrochromic Properties

“…The second method is related to the increase of the quinone character of the polymer backbone [ 19 ], and the third approach is characterized by the purposeful control of the region regularity of polythiophenes [ 20 ]. The fourth and most commonly used approach is called the donor-acceptor (D-A) method, which has the best synergistic effect between the alternately existing donor and acceptor units on the polymer backbone [ 21 , 22 ] and is generally considered the most effective way to reduce the band gaps of polymers.…”

Novel Thiadiazolobenzotriazole Based Donor–Acceptor Type Conjugated Polymers as Neutral Green Electrochromic Materials

“…[ 20–24 ] In these structures, two fused electron‐withdrawing groups will generate strong quinoid character with large electron delocalization and small steric hindrance, which is beneficial to reducing the bandgap and promoting the intermolecular π ‐ π interactions. [ 25,26 ] BBT, as one of the most popular planar triple‐fused‐ring, exhibits good planarity, strong electron‐withdrawing capability and excellent intermolecular π ‐ π interactions through fusing two BTd groups. [ 25,27,28 ] Furthermore, growing research has been devoted to developing another heteroatom‐substituted BBT analogous unit, namely TBZ, in order to further optimize the basic properties of corresponding polymers.…”

“…[ 25,26 ] BBT, as one of the most popular planar triple‐fused‐ring, exhibits good planarity, strong electron‐withdrawing capability and excellent intermolecular π ‐ π interactions through fusing two BTd groups. [ 25,27,28 ] Furthermore, growing research has been devoted to developing another heteroatom‐substituted BBT analogous unit, namely TBZ, in order to further optimize the basic properties of corresponding polymers. [ 18,23,29 ] For example, the TBZ group, considered as “marriage” of BTd and BTz via annulation, has been used to regulate the bandgap and improve the hole mobility of the TBZ‐based polymers.…”

“…[ 24 ] Ozkut and group synthesized a BBT and selenophene units based polymer which showed ambipolar property with multiple color changes and narrow bandgap of 0.63 eV. [ 25 ] Reynolds and group and Marder and group reported another soluble BBT‐bearing D–A type polymer with dithienopyrrole units as the donor, which also revealed a very low bandgap of 0.56 eV, as well as multichromic property and ambipolar character. [ 33 ] Although these BBT‐based polymers presented favorable electrochromic properties, they are usually synthesized by electrochemical polymerization, and even if synthetic method is chemical polymerization it is necessary to connect bulky branched alkyl chains on the flanking donor units to enhance the polymer solubility, which will be inconvenient to their commercial applications.…”

“…[ 33 ] Although these BBT‐based polymers presented favorable electrochromic properties, they are usually synthesized by electrochemical polymerization, and even if synthetic method is chemical polymerization it is necessary to connect bulky branched alkyl chains on the flanking donor units to enhance the polymer solubility, which will be inconvenient to their commercial applications. [ 24,25,34 ]…”