Comprehensive Summary,The development of novel building blocks with sp3-hybridized-carbon-free conjugated skeletons is important to further advance and enrich nonfullerene acceptors(NFAs),but this remains a challenge ...Comprehensive Summary,The development of novel building blocks with sp3-hybridized-carbon-free conjugated skeletons is important to further advance and enrich nonfullerene acceptors(NFAs),but this remains a challenge due to the lack of strategies to effectively modulate the aggregation behavior of resulting NFAs.Herein,two novel nitrogen-bridged octacyclic ladder-type heteroarenes end-capped with thiophene rings(BTPS)or selenophene rings(BTPSe)are designed and synthesized as the donor cores for constructing NFAs(MQX-2 and MQX-4).It is found that replacing the sulfur atoms(MQX-2)at the outer positions of the heteroarene core with selenium atoms(MQX-4)can effectively modulate the molecular packing mode of the NFAs.The incorporation of selenium atoms induces stronger O···Se noncovalent interaction than O···S,thus promoting the formation of mixed H/J-type aggregates in MQX-4.Benefiting from more electron hopping channels,MQX-4 exhibits higher electron transport(more than 1-fold enhancement)and photovoltaic properties compared to MQX-2,which forms only H-type aggregates.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52130306,22075287)the Program of Youth Innovation Promotion Association CAs(No.2021299).
文摘Comprehensive Summary,The development of novel building blocks with sp3-hybridized-carbon-free conjugated skeletons is important to further advance and enrich nonfullerene acceptors(NFAs),but this remains a challenge due to the lack of strategies to effectively modulate the aggregation behavior of resulting NFAs.Herein,two novel nitrogen-bridged octacyclic ladder-type heteroarenes end-capped with thiophene rings(BTPS)or selenophene rings(BTPSe)are designed and synthesized as the donor cores for constructing NFAs(MQX-2 and MQX-4).It is found that replacing the sulfur atoms(MQX-2)at the outer positions of the heteroarene core with selenium atoms(MQX-4)can effectively modulate the molecular packing mode of the NFAs.The incorporation of selenium atoms induces stronger O···Se noncovalent interaction than O···S,thus promoting the formation of mixed H/J-type aggregates in MQX-4.Benefiting from more electron hopping channels,MQX-4 exhibits higher electron transport(more than 1-fold enhancement)and photovoltaic properties compared to MQX-2,which forms only H-type aggregates.
