Investigating the backbone conformation and configuration effects for donor–acceptor conjugated polymers with ladder-type structures synthesized through Aldol polycondensation

Abstract

Aldol reaction is a green approach that is exclusively suitable for developing conjugated polymers (CPs) with ladder-type structures. Herein, electron-deficient non-fused and fused bis-isoindigo (bis-IID) are copolymerized with axisymmetric thiophene...

Material Design and Device Fabrication Strategies for Stretchable Organic Solar Cells

“…[ 79,101 ] For example, reducing the rigidity of the backbone of a polymer is predicted to improve its mechanical properties in film, as stiff polymer chains often yield strong polymer aggregation and brittle films. [ 101c ] On the other hand, in terms of electrical properties, rigid polymer chains provide high crystallinity and charge mobility in thin films. However, polymers with such rigid backbones do not necessarily guarantee high PCEs due to the nature of BHJ blend morphology; if the backbone of a polymer is too rigid, it is typically poorly soluble in a solvent and prone to self‐aggregation in the solution, resulting in severe phase separation and oversized domains within the blend film.…”

“…Lipomi et al reported guidelines for the rational design of stretchable active materials; they measured PCE, COS, and elastic modulus of 51 different alternating copolymers and compared their figure‐of‐merit (FOM) values (i.e., PCE × COS × (elastic modulus) −1 ) to identify the molecular structure that affords a film with superior photovoltaic and mechanical properties. [ 101b ] Their investigation revealed that polymers featuring non‐fused subunits tend to yield more ductile films than those featuring highly fused subunits. The best polymer in terms of the FOM was prepared via coupling of quinoxaline and non‐fused thiophene/benzene rings, which exhibited the lowest elastic modulus (0.15 GPa) and highest COS (56.8%).…”

“…The introduction of conjugation‐break spacers (CBSs) is another effective strategy to reduce the excessive backbone rigidity of polymers. [ 77,81,82,101d,105 ] The addition of a limited number of CBSs does not significantly impair the charge transport ability of polymers. This is because the effective conjugation length is generally shorter than the total length of the polymer chains due to torsional disorder and chemical defects.…”

Aldol Polymerization to Construct Half-Fused Semiconducting Polymers

“…These polymers exhibit high electron affinities above 4.2 eV and show a high-intensity near-infrared II (NIR-II) absorption band, along with superior air-stable electron transport than N2200 in solution-processing organic field-effect transistor devices . Very recently, two ladder-type polymers have been reported during the course of our work . However, the examples concentrating on the “green” synthesis of fused semiconducting polymers are very limited because of the lack of an ingenious strategy of the monomers.…”

“…16 Very recently, two ladder-type polymers have been reported during the course of our work. 17 However, the examples concentrating on the "green" synthesis of fused semiconducting polymers are very limited because of the lack of an ingenious strategy of the monomers. The device performance is not satisfying so far, 16,18,19 and the synthesis of the monomers is still tedious and low yielding.…”