Star-shaped small molecules have attracted great attention for organic solar cells(OSCs)because they have three-dimensional charge-transport characteristics,strong light absorption capacities and easily tunable energy...Star-shaped small molecules have attracted great attention for organic solar cells(OSCs)because they have three-dimensional charge-transport characteristics,strong light absorption capacities and easily tunable energy levels.Herein,three-and four-armed star-shaped small molecule donors,namely BDT-3 Th and BDT-4 Th,respectively,have been successfully designed and synthesized,which used benzodithiophene(BDT)as the central unit.The two star-shaped intermediates(2 a and 2 b)could be simultaneously obtained by one-step of Suzuki coupling,and 1,2-dimethoxyethane played a key role in the Suzuki coupling.Both of them have excellent thermal stability,good solubility and broad absorption.Four-armed BDT-4 Th shows a slightly higher extinction coefficient,a deeper HOMO energy level and an obviously better phase separation morphology when blended with Y6 than three-armed BDT-3 Th.As a result,increased power conversion efficiency(PCE)of 5.83%is obtained in the BDT-4 Th:Y6-based OSC devices,which is obviously higher than that of the BDT-3 Th:Y6-based devices(PCE=3.78%).To the best of our knowledge,this is the highest PCE among the BDT-based star-shaped donors-based OSCs.This result provides an effective strategy to obtain star-shaped small molecule donor materials for high efficient organic solar cells.展开更多
To achieve high-efficiency organic solar cells(OSCs),the introduction of vip molecules into binary blended films(D:A system)has become the most effective method.However,the molecular design rules for vip molecules...To achieve high-efficiency organic solar cells(OSCs),the introduction of vip molecules into binary blended films(D:A system)has become the most effective method.However,the molecular design rules for vip molecules that achieve the goals by reducing voltage losses have been rarely reported.Here,guided by the molecular electrostatic potential(ESP)derived from density functional theory(DFT)calculations,we present a rationally designed vip acceptor,ANF-4,featuring very weak electrostatic interactions compared to the benchmark acceptor BTP-eC9.The larger ESP difference promotes stronger intermolecular interactions and higher miscibility.The addition of ANF-4 significantly alters the morphology of the binary system by suppressing the excessive aggregation of BTP-eC9,which leads to improved charge separation,reduced trap-assisted recombination,and efficient carrier transport.Consequently,the PM6:BTP-eC9:ANF-4-controlled device exhibits an improved radiative limit open-circuit voltage(V^(rad)_(OC))while significantly reducing non-radiative voltage loss(ΔV_(nr)),thus achieving a remarkable increase in open circuit voltage(V_(OC))of 33 mV.As a result,the device produces a new benchmark power conversion efficiency(PCE)of 20.23%(certified 20.0%)with a remarkably VOC of 0.876 V.This work provides a promising way to develop efficient vip molecules,thereby pushing the OSCs technology closer to commercial application.展开更多
Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a ...Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a template for perovskite growth,which is critical for enhancing the device performance.However,the current research on how the HTL promotes perovskite crystallization is insufficient.Here,4PADCB,a self-assembled monolayer(SAM)hole transport material,was optimized as a superior template for perovskite growth through comparative analysis;accordingly,compact perovskite film with vertical growth was prepared.The better matched energy level alignment between 4PADCB and perovskite suppressed nonradiative recombination at the interface and enabled rapid hole extraction.Moreover,high-quality perovskite film growth on 4PADCB exhibited lower Young's modulus and less residual stress.By integrating 4PADCB into p-i-n PSCs,the optimal device achieved a power conversion efficiency of 24.80%,with an open-circuit voltage of 1.156 V,thus achieving the best rank among devices without perovskite post-treatment,additives,dopants,or intermediate layers.Furthermore,the unencapsulated device demonstrated exceptional thermostability and photostability under maximum power point tracking.Thus,this work provides a new understanding for the development of novel SAMs and perovskite growth,and it is expected to further improve device performance.展开更多
The effect of side-chain engineering of conjugated molecules on the morphology and device performance in binary organic solar cells has been widely investigated. However, this relationship has hardly been studied in t...The effect of side-chain engineering of conjugated molecules on the morphology and device performance in binary organic solar cells has been widely investigated. However, this relationship has hardly been studied in the vip components of ternary organic solar cells. In this study, a family of non-fullerene vip acceptors, namely XY-3, XY-5 and XY-7, with hydrogen substituent,straight and branched alkyl chains on the bithiophene units, respectively, were designed and synthesized to understand their effects on aggregation properties and device performance. The straight and branched alkyl chains on the bithiophene units result in sightly blue-shifted absorption compared to the hydrogen substituent and the XY-7 demonstrates the most appropriate phase separation scale and the most balanced charge transport. Consequently, the OSCs based on D18:e C9:XY-7 achieve a high shortcircuit current density(JSC) and fill factor(FF), while maintaining the enhancement of the open-circuit voltage(VOC) achieving an efficiency of 19.32%, exceeding those of D18:e C9, D18:e C9:XY-3, D18:e C9:XY-5(PCE:18.28%, 19.04%, 18.75%, respectively). These results highlight that the side-chain engineering of Y series non-fullerene acceptors as the vip acceptors has great potential in optimizing morphology properties and promoting photovoltaic performance.展开更多
The construction of C-N bonds is of great importance in the fields of biology,medicine,chemistry and materials science.Here,the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation p...The construction of C-N bonds is of great importance in the fields of biology,medicine,chemistry and materials science.Here,the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation process unexpectedly yields a series of novel organic molecules containing C-N bonds.Interestingly,the synthesis method does not require any external transition-metals catalysis,and photo-/electro-catalysis.Additionally,when the new compound 1b is added as a third component to a well-known binary system of PM6:Y6,the efficiency of the organic solar cell is significantly improved,resulting in an outstanding efficiency of 18.0%,which is one of the highest values reported to date for PM6:Y6-based ternary organic solar cells.展开更多
基金the financial support for this work by the National Science Fund for Distinguished Young Scholars(No.21925506)National Natural Science Foundation of China(No.51773212)Ningbo S&T Innovation 2025 Major Special Program(No.2018B10055)。
文摘Star-shaped small molecules have attracted great attention for organic solar cells(OSCs)because they have three-dimensional charge-transport characteristics,strong light absorption capacities and easily tunable energy levels.Herein,three-and four-armed star-shaped small molecule donors,namely BDT-3 Th and BDT-4 Th,respectively,have been successfully designed and synthesized,which used benzodithiophene(BDT)as the central unit.The two star-shaped intermediates(2 a and 2 b)could be simultaneously obtained by one-step of Suzuki coupling,and 1,2-dimethoxyethane played a key role in the Suzuki coupling.Both of them have excellent thermal stability,good solubility and broad absorption.Four-armed BDT-4 Th shows a slightly higher extinction coefficient,a deeper HOMO energy level and an obviously better phase separation morphology when blended with Y6 than three-armed BDT-3 Th.As a result,increased power conversion efficiency(PCE)of 5.83%is obtained in the BDT-4 Th:Y6-based OSC devices,which is obviously higher than that of the BDT-3 Th:Y6-based devices(PCE=3.78%).To the best of our knowledge,this is the highest PCE among the BDT-based star-shaped donors-based OSCs.This result provides an effective strategy to obtain star-shaped small molecule donor materials for high efficient organic solar cells.
基金supported by the National Science Fund for Distinguished Young Scholars(21925506)the National Natural Science Foundation of China(U21A20331,22439004,22409202)the National Postdoctoral Program for Innovative Talents(BX20230386)。
文摘To achieve high-efficiency organic solar cells(OSCs),the introduction of vip molecules into binary blended films(D:A system)has become the most effective method.However,the molecular design rules for vip molecules that achieve the goals by reducing voltage losses have been rarely reported.Here,guided by the molecular electrostatic potential(ESP)derived from density functional theory(DFT)calculations,we present a rationally designed vip acceptor,ANF-4,featuring very weak electrostatic interactions compared to the benchmark acceptor BTP-eC9.The larger ESP difference promotes stronger intermolecular interactions and higher miscibility.The addition of ANF-4 significantly alters the morphology of the binary system by suppressing the excessive aggregation of BTP-eC9,which leads to improved charge separation,reduced trap-assisted recombination,and efficient carrier transport.Consequently,the PM6:BTP-eC9:ANF-4-controlled device exhibits an improved radiative limit open-circuit voltage(V^(rad)_(OC))while significantly reducing non-radiative voltage loss(ΔV_(nr)),thus achieving a remarkable increase in open circuit voltage(V_(OC))of 33 mV.As a result,the device produces a new benchmark power conversion efficiency(PCE)of 20.23%(certified 20.0%)with a remarkably VOC of 0.876 V.This work provides a promising way to develop efficient vip molecules,thereby pushing the OSCs technology closer to commercial application.
基金supported by the National Science Fund for Distinguished Young Scholars(21925506)National Natural Science Foundation of China(U21A20331,81903743,22209192 and 62275251)+1 种基金Natural Science Foundation of Zhejiang Province(LY24F040002)China Postdoctoral Science Foundation(2022M713242).
文摘Inverted(p-i-n)perovskite solar cells(PSCs)are favored by researchers owing to their superior compatibility with flexible substrates and tandem device fabrication.Additionally,the hole transport layer(HTL)serves as a template for perovskite growth,which is critical for enhancing the device performance.However,the current research on how the HTL promotes perovskite crystallization is insufficient.Here,4PADCB,a self-assembled monolayer(SAM)hole transport material,was optimized as a superior template for perovskite growth through comparative analysis;accordingly,compact perovskite film with vertical growth was prepared.The better matched energy level alignment between 4PADCB and perovskite suppressed nonradiative recombination at the interface and enabled rapid hole extraction.Moreover,high-quality perovskite film growth on 4PADCB exhibited lower Young's modulus and less residual stress.By integrating 4PADCB into p-i-n PSCs,the optimal device achieved a power conversion efficiency of 24.80%,with an open-circuit voltage of 1.156 V,thus achieving the best rank among devices without perovskite post-treatment,additives,dopants,or intermediate layers.Furthermore,the unencapsulated device demonstrated exceptional thermostability and photostability under maximum power point tracking.Thus,this work provides a new understanding for the development of novel SAMs and perovskite growth,and it is expected to further improve device performance.
基金supported by the National Natural Science Foundation of China (U21A20331)the National Science Fund for Distinguished Young Scholars (21925506)the Zhejiang Provincial Natural Science Foundation (LQ22E030013)。
文摘The effect of side-chain engineering of conjugated molecules on the morphology and device performance in binary organic solar cells has been widely investigated. However, this relationship has hardly been studied in the vip components of ternary organic solar cells. In this study, a family of non-fullerene vip acceptors, namely XY-3, XY-5 and XY-7, with hydrogen substituent,straight and branched alkyl chains on the bithiophene units, respectively, were designed and synthesized to understand their effects on aggregation properties and device performance. The straight and branched alkyl chains on the bithiophene units result in sightly blue-shifted absorption compared to the hydrogen substituent and the XY-7 demonstrates the most appropriate phase separation scale and the most balanced charge transport. Consequently, the OSCs based on D18:e C9:XY-7 achieve a high shortcircuit current density(JSC) and fill factor(FF), while maintaining the enhancement of the open-circuit voltage(VOC) achieving an efficiency of 19.32%, exceeding those of D18:e C9, D18:e C9:XY-3, D18:e C9:XY-5(PCE:18.28%, 19.04%, 18.75%, respectively). These results highlight that the side-chain engineering of Y series non-fullerene acceptors as the vip acceptors has great potential in optimizing morphology properties and promoting photovoltaic performance.
基金supported by the National Natural Science Foundation of China(U21A20331)the National Science Fund for Distinguished Young Scholars(21925506)the Zhejiang Provincial Natural Science Foundation of China(LQ22E030013)。
文摘The construction of C-N bonds is of great importance in the fields of biology,medicine,chemistry and materials science.Here,the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation process unexpectedly yields a series of novel organic molecules containing C-N bonds.Interestingly,the synthesis method does not require any external transition-metals catalysis,and photo-/electro-catalysis.Additionally,when the new compound 1b is added as a third component to a well-known binary system of PM6:Y6,the efficiency of the organic solar cell is significantly improved,resulting in an outstanding efficiency of 18.0%,which is one of the highest values reported to date for PM6:Y6-based ternary organic solar cells.
