As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by ...As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity concerns.It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs industrialization.Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction byproducts.This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions.Especially,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.展开更多
To achieve the red-shifted absorptions and appropriate energy levels of A-D-A type non-fullerene acceptors(NFAs), in this work, we design and synthesize two new NFAs, named TPDCIC and TPDCNC, whose electron-donating(D...To achieve the red-shifted absorptions and appropriate energy levels of A-D-A type non-fullerene acceptors(NFAs), in this work, we design and synthesize two new NFAs, named TPDCIC and TPDCNC, whose electron-donating(D) unit is constructed by a thieno[3,4-c]pyrrole-4,6-dione(TPD) core attached to two cyclopentadithiophene(CPDT) moieties at both sides, and the electronaccepting(A) end-groups are 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile(IC) and 2-(3-oxo-2,3-dihydro-1 H-cyclopenta[b]naphthalen-1-ylidene)malononitrile(NC), respectively. Benefiting from TPD core, which easily forms quinoid structure and O···H or O···S intramolecular noncovalent interactions, TPDCIC and TPDCNC show more delocalization of π-electrons and perfect planar molecular geometries, giving the absorption ranges extended to 822 and 852 nm, respectively. Furthermore, the highest occupied molecular orbital(HOMO) levels of TPDCIC and TPDCNC remain relatively low-lying due to the electronegativity of the carbonyl groups on TPD core. Considering that the absorptions and energy levels of the two NFAs match well with those of a widely used polymer donor, PBDB-T, we fabricate two kinds of organic solar cells(OSCs) based on the PBDB-T:TPDCIC and PBDB-T:TPDCNC blended films, respectively. Through a series of optimizations, the TPDCIC-based devices yield an impressing power conversion efficiency(PCE)of 10.12% with a large short-circuit current density(JSC) of 18.16 mA·cm-2, and the TPDCNC-based ones exhibit a comparable PCE of9.80% with a JSC of 17.40 mA·cm-2. Our work is the first report of the TPD-core-based A-D-A type NFAs, providing a good reference for the molecular design of high-performance NFAs.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
Organic semiconductor materials with low reorganization energy have various applications such as in organic light-emitting diodes (OLEDs),organic field-effect transistor (OFETs) and organic solar cells (OSCs).In this ...Organic semiconductor materials with low reorganization energy have various applications such as in organic light-emitting diodes (OLEDs),organic field-effect transistor (OFETs) and organic solar cells (OSCs).In this work,we have designed a new class of gridspiroarenes (GS-SFX and GS-SITF) with #-shaped structures,which have novel crisscross geometrical structures compared to widely used spirocyclic arenes-SFX and SITF.The structure electronic properties,adiabatic ionization potentials (IPa),adiabatic electron affinities (EAa) and reorganization energies (λ) of GS-SFX and GS-SITF have been calculated using density functional theory (DFT) method.The calculated HOMO and LUMO spatial distributions suggest that GS-SFX and GS-SITF have better transport properties.The noncovalent interaction analysis shows the weak intramolecular interactions between their arms.The results indicate that the reorganization energies of GS-SFX and GS-SITF are significantly reduced compared to the dimer structures-DSFX and DSITF.Furthermore,the GS-SITF1 which is one of the isomers of GS-SITF exhibits the lowest values for λ(h)(0.067 eV) and λ(e)(0.153 eV).Therefore,we believe the predicted structure,electronic property,and reorganization energy are good indicator for transport materials.This work has systematically studied the effect of gridization,which provides insights to design organic semiconductor materials with excellent charge transport properties.展开更多
基金the National Natural Science Foundation of China(No.51773046)the Fundamental Research Funds for the Central Universities,the School of Materials Science and Engineering,Shaanxi Normal Universitythe Project of Key Laboratory of Organic Synthesis of Jiangsu Province,College of Chemistry Chemical Engineering and Materials Science,Soochow University。
文摘As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity concerns.It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs industrialization.Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction byproducts.This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions.Especially,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.
基金financially supported by the National Natural Science Foundation of China (Nos. 21875216, 21734008)Zhejiang Province Science and Technology Plan (No. 2018C01047)the financial support from Research Grant Council of Hong Kong (General Research Fund No. 14314216, CUHK Direct Grant No. 4053227)
文摘To achieve the red-shifted absorptions and appropriate energy levels of A-D-A type non-fullerene acceptors(NFAs), in this work, we design and synthesize two new NFAs, named TPDCIC and TPDCNC, whose electron-donating(D) unit is constructed by a thieno[3,4-c]pyrrole-4,6-dione(TPD) core attached to two cyclopentadithiophene(CPDT) moieties at both sides, and the electronaccepting(A) end-groups are 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile(IC) and 2-(3-oxo-2,3-dihydro-1 H-cyclopenta[b]naphthalen-1-ylidene)malononitrile(NC), respectively. Benefiting from TPD core, which easily forms quinoid structure and O···H or O···S intramolecular noncovalent interactions, TPDCIC and TPDCNC show more delocalization of π-electrons and perfect planar molecular geometries, giving the absorption ranges extended to 822 and 852 nm, respectively. Furthermore, the highest occupied molecular orbital(HOMO) levels of TPDCIC and TPDCNC remain relatively low-lying due to the electronegativity of the carbonyl groups on TPD core. Considering that the absorptions and energy levels of the two NFAs match well with those of a widely used polymer donor, PBDB-T, we fabricate two kinds of organic solar cells(OSCs) based on the PBDB-T:TPDCIC and PBDB-T:TPDCNC blended films, respectively. Through a series of optimizations, the TPDCIC-based devices yield an impressing power conversion efficiency(PCE)of 10.12% with a large short-circuit current density(JSC) of 18.16 mA·cm-2, and the TPDCNC-based ones exhibit a comparable PCE of9.80% with a JSC of 17.40 mA·cm-2. Our work is the first report of the TPD-core-based A-D-A type NFAs, providing a good reference for the molecular design of high-performance NFAs.
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.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21503114, 21774061, 61605090, 91833306)Synergetic Innovation Centre for Organic Electronics and In formation Displays, Nanji ng Un iversity of Posts a nd Telecommunications Scientific Foundation NUPTSF (NY215056, NY21417& NY215172, 2016XSG03)the Six Peak Talents Foundation of Jiangsu Province (XCL-CXTD-009), and the High Performanee Computing Center of Nanjing Tech University.
文摘Organic semiconductor materials with low reorganization energy have various applications such as in organic light-emitting diodes (OLEDs),organic field-effect transistor (OFETs) and organic solar cells (OSCs).In this work,we have designed a new class of gridspiroarenes (GS-SFX and GS-SITF) with #-shaped structures,which have novel crisscross geometrical structures compared to widely used spirocyclic arenes-SFX and SITF.The structure electronic properties,adiabatic ionization potentials (IPa),adiabatic electron affinities (EAa) and reorganization energies (λ) of GS-SFX and GS-SITF have been calculated using density functional theory (DFT) method.The calculated HOMO and LUMO spatial distributions suggest that GS-SFX and GS-SITF have better transport properties.The noncovalent interaction analysis shows the weak intramolecular interactions between their arms.The results indicate that the reorganization energies of GS-SFX and GS-SITF are significantly reduced compared to the dimer structures-DSFX and DSITF.Furthermore,the GS-SITF1 which is one of the isomers of GS-SITF exhibits the lowest values for λ(h)(0.067 eV) and λ(e)(0.153 eV).Therefore,we believe the predicted structure,electronic property,and reorganization energy are good indicator for transport materials.This work has systematically studied the effect of gridization,which provides insights to design organic semiconductor materials with excellent charge transport properties.
