Search

Polymerized small molecule acceptors have recently greatly facilitated the development of all‐polymer solar cells (All‐PSCs) with respect to the power conversion efficiencies (PCEs). However, high‐performance and low‐cost polymer donors for All‐PSCs are still lacking, limiting further large‐scale manufacturing of All‐PSCs. Herein, this work designs and synthesizes a new thiophene derivative, FETVT, featuring vinyl‐bridged fluorine and ester‐substituted monothiophene. Incorporation of FETVT into a polymer yields a high‐performance polythiophene derivative PFETVT‐T, which exhibits deep‐lying HOMO level, suitable solution pre‐aggregation ability, finely‐tuned polymer crystallinity, and appropriate thermodynamic miscibility with the polymer acceptor L15. As a result, binary based on PFETVT‐T achieves a record PCE of 11.81% with agood stability, representing a breakthrough for polythiophenes and their derivatives‐based All‐PSCs, which is also significantly higher than that (1.92%) of All‐PSCs based on its isomerized analog. Remarkably, PFETVT‐T achieves an impressive PCE exceeding 16% via the implementation of a ternary blend design. These findings offer a hopeful pathway toward attaining high‐performance, stable, and cost‐effective PSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Bithiophene imide (BTI)‐based polymers have been promising photovoltaic materials due to their high mobility and tunable energy levels. However, BTI polymers have rarely been revisited since organic solar cells (OSCs) entered the era of non‐fullerene electron acceptors (NFEA) likely owing to their incompatibility with NFEAs. Herein, fine‐tuning the aggregation and orientation of BTI‐based donor‐π‐acceptor (D‐π‐A) polymer donors was achieved by incorporating the linear n‐octyl group into thiophene π‐bridge. The resulting polymer donor G15 shows excellent compatibility with NFEA L15 (polymer acceptor). The G15‐based all‐polymer OSCs achieve high power conversion efficiency of 15.17%. This is significantly higher than that (< 5%) of its analogue with isomerized branched alkyl chains and also among the highest values for all‐polymer OSCs. The results highlight that well‐tailored BTI polymer donors are attractive photovoltaic materials for further exploration in non‐fullerene organic solar cells. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Bithiophene imide (BTI)‐based polymers have been promising photovoltaic materials due to their high mobility and tunable energy levels. However, BTI polymers have rarely been revisited since organic solar cells (OSCs) entered the era of non‐fullerene electron acceptors (NFEA) likely owing to their incompatibility with NFEAs. Herein, fine‐tuning the aggregation and orientation of BTI‐based donor‐π‐acceptor (D‐π‐A) polymer donors was achieved by incorporating the linear n‐octyl group into thiophene π‐bridge. The resulting polymer donor G15 shows excellent compatibility with NFEA L15 (polymer acceptor). The G15‐based all‐polymer OSCs achieve high power conversion efficiency of 15.17%. This is significantly higher than that (< 5%) of its analogue with isomerized branched alkyl chains and also among the highest values for all‐polymer OSCs. The results highlight that well‐tailored BTI polymer donors are attractive photovoltaic materials for further exploration in non‐fullerene organic solar cells. [ABSTRACT FROM AUTHOR]