The ternary strategy has demonstrated its efficacy in improving charge transport in organic solar cells(OSCs).Here,three novel non-fullerene acceptors,SN6C9-4F,SN6C9-4Cl and SN6C10-4F,based on S,N-heteroacene linear b...The ternary strategy has demonstrated its efficacy in improving charge transport in organic solar cells(OSCs).Here,three novel non-fullerene acceptors,SN6C9-4F,SN6C9-4Cl and SN6C10-4F,based on S,N-heteroacene linear backbone were designed and synthesized.The three acceptors exhibit excellent molecular coplanarity,high crystallinity and possess a deep-lying lowest unoccupied molecular orbital energy level,which is beneficial for charge transport and injection in organic field-effect transistors(OFETs).Notably,the OFET devices based on all three acceptors achieved impressive electron mobilities,with SN6C10-4F achieving up to 0.73 cm^(2)·V^(-1)·s^(-1),which is one of the highest values among A-D-A type small molecules.In addition,the OSCs device based on PBDB-T:SN6C9-4F exhibited the best power conversion efficiency of 12.07%owing to its optimal morphology and enhanced charge transport.Moreover,the incorporation of SN6C9-4F into the efficient PM6:L8-BO binary system to form ternary OSCs resulted in extended absorption range,enhanced donor crystallization,improved and more balanced charge transport,ultimately leading to an improvement of PCE from 17.78%to 18.32%.This study highlights the potential of developing acceptors with distinct structures from Y-series acceptors to broaden absorption and regulate donor crystallization,providing a novel approach to enhance the PCE of OSCs.展开更多
A near-infrared non-fullerene acceptor(NFA) BDTIC, based on thienopyrrole-expanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) as core, is designed and synthesized. The aromatic pyrrole ring with...A near-infrared non-fullerene acceptor(NFA) BDTIC, based on thienopyrrole-expanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) as core, is designed and synthesized. The aromatic pyrrole ring with strong electron-donating ability in the core enhances the intramolecular charge transfer effect, finely tunes the optical bandgap and absorption profile of BDTIC, and thus results in a narrowed optical bandgap(E_(g)^(opt)) of 1.38 eV and a near-infrared absorption to 900 nm. When BDTIC is paired with donor polymer PBDB-T to fabricate organic solar cells, the optimized device achieves a best power conversion efficiency of 12.1% with a short-circuit current density of 20.0 mA·cm^(-2) and an open-circuit voltage of 0.88 V. The photovoltaic performance benefits from the broad absorption, weak bimolecular recombination, efficient charge separation and collection, and favorable blend morphology. This work demonstrates that thienopyrroleexpanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) is a promising building unit to construct high-performance NFAs by enhancing the intramolecular charge transfer effect, broadening absorption as well as maintaining good intermolecular stacking property.展开更多
基金financially supported by the National Natural Science Foundation of China(NSFC)(52333006,51973032,21905043,22275078 and 52173171)the Jiangxi Provincial Natural Science Foundation(20212ACB203005,20224ACB214002)+1 种基金the Thous and Talents Plan of Jiangxi Province(jxsq2019101051)financial support from Research Grants Council(RGC)of Hong Kong(General Research Fund No.14303519).
文摘The ternary strategy has demonstrated its efficacy in improving charge transport in organic solar cells(OSCs).Here,three novel non-fullerene acceptors,SN6C9-4F,SN6C9-4Cl and SN6C10-4F,based on S,N-heteroacene linear backbone were designed and synthesized.The three acceptors exhibit excellent molecular coplanarity,high crystallinity and possess a deep-lying lowest unoccupied molecular orbital energy level,which is beneficial for charge transport and injection in organic field-effect transistors(OFETs).Notably,the OFET devices based on all three acceptors achieved impressive electron mobilities,with SN6C10-4F achieving up to 0.73 cm^(2)·V^(-1)·s^(-1),which is one of the highest values among A-D-A type small molecules.In addition,the OSCs device based on PBDB-T:SN6C9-4F exhibited the best power conversion efficiency of 12.07%owing to its optimal morphology and enhanced charge transport.Moreover,the incorporation of SN6C9-4F into the efficient PM6:L8-BO binary system to form ternary OSCs resulted in extended absorption range,enhanced donor crystallization,improved and more balanced charge transport,ultimately leading to an improvement of PCE from 17.78%to 18.32%.This study highlights the potential of developing acceptors with distinct structures from Y-series acceptors to broaden absorption and regulate donor crystallization,providing a novel approach to enhance the PCE of OSCs.
基金financially supported by the National Key Research and Development Program of China(No.2019YFA0705900)funded by MOST+1 种基金the Basic and Applied Basic Research Major Program of Guangdong Province(No.2019B030302007)the Pearl River Nova Program of Guangzhou(NO.201906010074)。
文摘A near-infrared non-fullerene acceptor(NFA) BDTIC, based on thienopyrrole-expanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) as core, is designed and synthesized. The aromatic pyrrole ring with strong electron-donating ability in the core enhances the intramolecular charge transfer effect, finely tunes the optical bandgap and absorption profile of BDTIC, and thus results in a narrowed optical bandgap(E_(g)^(opt)) of 1.38 eV and a near-infrared absorption to 900 nm. When BDTIC is paired with donor polymer PBDB-T to fabricate organic solar cells, the optimized device achieves a best power conversion efficiency of 12.1% with a short-circuit current density of 20.0 mA·cm^(-2) and an open-circuit voltage of 0.88 V. The photovoltaic performance benefits from the broad absorption, weak bimolecular recombination, efficient charge separation and collection, and favorable blend morphology. This work demonstrates that thienopyrroleexpanded benzo[1,2-b:4,5-b′]dithiophene unit(heptacyclic S,N-heteroacene) is a promising building unit to construct high-performance NFAs by enhancing the intramolecular charge transfer effect, broadening absorption as well as maintaining good intermolecular stacking property.
