Carboxamide and carbamate substituted π-conjugated polymers: the effect of hydrogen bonding on photovoltaic properties

Abstract

Thiophene-pyrazine-thiophene building blocks with carboxamide or carbamate substituents were synthesized and their crystal structures were compared. The carboxamide substituted building block formed intermolecular hydrogen bonds. It showed twisted conformations and...

Hydrogen-bonded polyazomethines for efficient organic solar cells

“…These intramolecular hydrogen bonds which occur in a six-membered, p-conjugated ring (NQC-CQC-N-H) are typical resonance assisted hydrogen bonds (RAHBs). [36][37][38][39][40][41] With the influence of the p-electron delocalization, the RAHBs are stronger than normal hydrogen bonds and have partial covalent characters. The six membered quasi aromatic rings which formed by the RAHBs could lock thiophene rings and azomethine moieties into near coplanar conformations.…”

Control of Properties through Hydrogen Bonding Interactions in Conjugated Polymers

“…Zhang et al also synthesized the thiophene-pyrazine-thiophene building blocks with carbamate substituents where intramolecular hydrogen bonds were able to form within the polymer backbone. [73] Interestingly, the PCE of the devices based on P32 with intramolecular hydrogen bonds was 5-8%, while the PCE of the devices based on P31 with intermolecular hydrogen bonds was 0.1%, which is attributed to the higher bimolecular recombination, geminate recombination, and reduced face-on orientation of the blend.…”

“…A perfectly alternating polymerization strategy includes the amide or carbamate functionalized monomer as the only comonomer such as P29-P32, P34-P36, and P42-P43. [72][73][74][75] It is [50,75] worth noting that the amide and carbamate functionalized perfectly alternative polymers P29-P32 and P34-P36 all have a reasonable molecular weight (with M n higher than 50 kg mol −1 ). P42 and P43 have lower molecular weight (10-15 kg mol −1 ) and this might be due to the end capping effect which introduces monobromo or monostannyl compound to stop the chain growing.…”