We synthesize and compare four near-infrared absorbing fused-ring electron acceptors named as nTTIC(n=2,3,4,and 5),based on different number of thieno[3,2-b]thiophene(TT)unit as the electron-donating core.With increas...We synthesize and compare four near-infrared absorbing fused-ring electron acceptors named as nTTIC(n=2,3,4,and 5),based on different number of thieno[3,2-b]thiophene(TT)unit as the electron-donating core.With increasing the TT unit,absorption spectrum of the TTIC series red shifts,and the highest occupied molecular orbital(HOMO)upshifts notably.It is worth noting that 4TTIC and 5TTIC exhibit absorption edges approaching 1100 nm,which is the photoresponse limit of solar cells based on crystal silicon.When the TTIC series acceptors are blended with polymer donor PM6,the binary-blend organic solar cells based on 3TTIC show the best power conversion efficiency(PCE)of 13.1%.In contrast,2TTIC-based devices exhibit relatively lower PCE of 8.32%,mainly caused by the larger energy loss and blue-shifted absorption.Due to insufficient driving force of charge separation caused by very high HOMO,4TTIC and 5TTIC show poor PCEs lower than 3%.展开更多
Fullerene derivatives are classic electron acceptor materials for organic solar cells (Oscs) but possess some intrinsic drawbacks such as weak visiblelightabsorption,limitedoptoelectronic property tunability,dificult ...Fullerene derivatives are classic electron acceptor materials for organic solar cells (Oscs) but possess some intrinsic drawbacks such as weak visiblelightabsorption,limitedoptoelectronic property tunability,dificult purification and photochemical/morphological instability.Fullereneacceptors area bottleneck restricting further development of this field. Ourgroup pioneered the exploration of novel nonfulerene acceptors in China in 2006,andinitiated the research of two representative acceptor systems, rylene dimide polymer and fused-ring electron acceptor (FREA).FREA breaks the theoreticalefficiencylimit of fullerene-based OsCs (-13%) and promotes the whole field to an unprecedented prosperity with efficiency of 20%, heraldinga nonfullerene era for OsCs.In this review, we revisit 15-year nonfullerene exploration journey,summarize the design principles,molecular engineeringstrategies, physical mechanisms and device applications of these two nonfullerene acceptor systems, and propose some possible researchtopics in the nearfuture.展开更多
We propose a strategy to improve performance of unidirectionally extended fused-ring electron acceptors by using pyrrolo[3,2-b]pyrrole to replace pyrrole ring, and design two asymmetric nonfullerene acceptors 1PIC and...We propose a strategy to improve performance of unidirectionally extended fused-ring electron acceptors by using pyrrolo[3,2-b]pyrrole to replace pyrrole ring, and design two asymmetric nonfullerene acceptors 1PIC and 2PIC. Replacing pyrrole in 1PIC with pyrrolo[3,2-b]pyrrole remarkably red-shifts absorption peak by 109 nm, elevates the HOMO and LUMO energy levels, and improves electron mobility. The photovoltaic devices based on blend of PM6 donor and 2PIC acceptor exhibit power conversion efficiency as high as 12.6%, which is much higher than that of PM6:1PIC (3.53%), due to more efficient exciton generation and dissociation, faster and more balanced carrier transport and less charge recombination.展开更多
The polymerization of fused-ring acceptors(FRAs) to afford their corresponding polymeric acceptors for high-performance all-polymer solar cells(all-PSCs) has achieved remarkable progress in the past few years.However,...The polymerization of fused-ring acceptors(FRAs) to afford their corresponding polymeric acceptors for high-performance all-polymer solar cells(all-PSCs) has achieved remarkable progress in the past few years.However,due to the high degree of synthetic complexity for the monomer,the high-cost of these polymeric acceptors may limit their commercial applications.Thus,it is urgent to develop inexpensive and high-performance polymeric acceptors for all-PSCs.Herein,two novel polymeric acceptors(PBTzO and PBTzO-2F) have been designed and synthesized by copolymerization of noncovalently fused ring acceptors(NFRAs),which were employed in all-PSCs for the first time.Upon introducing the “noncovalently conformational locks(NoCLs)” in the backbone and selective fluorination of the end-group,photophysical and electrical properties,and solidstate packing properties of the NFRAs have been rationally tuned.As a result,the PBDB-T:PBTzO-2F based devices presented an excellent power conversion efficiency(PCE) of 11.04%,much higher than that of PBTzO based ones due to the increased charge generation and extraction,improved hole transfer and carrier mobilities,and reduced energy loss.More importantly,PBTzO-2F exhibited a much lower synthetic complexity(SC) index and higher figure-of-merit(FOM) values than the high-performance fused-ring acceptor based polymer acceptors(FRA-PAs) due to the simpler structures and more effective synthesis.This contribution provided a novel idea to achieve low-cost and high-performance all-PSCs.展开更多
It is challenging to develop molecular fluorophores in the second near-infrared(NIR-Ⅱ)window with long wavelength emission and high brightness,which can improve the performance of biological imaging.Herein,we report ...It is challenging to develop molecular fluorophores in the second near-infrared(NIR-Ⅱ)window with long wavelength emission and high brightness,which can improve the performance of biological imaging.Herein,we report a molecular engineering approach to afford NIR-Ⅱ fluorophores with these merits based on fused-ring acceptor(FRA)molecules.Dioctyl 3,4-propylenedioxy thiophene(PDOT-C8)is utilized as the bridging donor to replace 3-ethylhexyloxy thiophene(3-EHOT),leading to more than 20 times enhancement of brightness.The nanofluorophores(NFs)based on the optimized CPTIC-4F molecule exhibit an emission peak of 1,110 nm with a fluorescence quantum yield(QY)of 0.39%(QY of IR-26 is 0.050%in dichloroethane as reference)and peak absorption coefficient of 14.5 x 10^4 M^-1·cm^-1 in aqueous solutions,which are significantly higher than those of 3-EHOT based COTIC-4F NFs.It is found that PDOT-C8 can weaken intermolecular aggregation,enhance protection of molecular backbone from water,and decrease backbone distortion,beneficial for the high brightness.Compared with indocyanine green with same injection dose,CPTIC-4F NFs show 10 times higher signal-to-background ratio for whole body vessels imaging at 1,300 nm long pass filters.展开更多
The power conversion efficiencies(PCEs)of organic solar cells(OSCs)have improved considerably in recent years with the development of fused-ring electron acceptors(FREAs).Currently,FREAs-based OSCs have achieved high ...The power conversion efficiencies(PCEs)of organic solar cells(OSCs)have improved considerably in recent years with the development of fused-ring electron acceptors(FREAs).Currently,FREAs-based OSCs have achieved high PCEs of over 19%in single-junction OSCs.Whereas the relatively high synthetic complexity and the low yield of FREAs typically result in high production costs,hindering the commercial application of OSCs.In contrast,noncovalently fused-ring electron acceptors(NFREAs)can compensate for the shortcomings of FREAs and facilitate large-scale industrial production by virtue of the simple structure,facile synthesis,high yield,low cost,and reasonable efficiency.At present,OSCs based on NFREAs have exceeded the PCEs of 15%and are expected to reach comparable efficiency as FREAs-based OSCs.Here,recent advances in NFREAs in this review provide insight into improving the performance of OSCs.In particular,this paper focuses on the effect of the chemical structures of NFREAs on the molecule conformation,aggregation,and packing mode.Various molecular design strategies,such as core,side-chain,and terminal group engineering,are presented.In addition,some novel polymer acceptors based on NFREAs for all-polymer OSCs are also introduced.In the end,the paper provides an outlook on developing efficient,stable,and low-cost NFREAs for achieving commercial applications.展开更多
All-fused-ringπ-conjugated molecules have received considerable attention because of their unique electronic structures,low conformation disorder,and excellent optoelectronic properties.Most all-fused-ring molecules ...All-fused-ringπ-conjugated molecules have received considerable attention because of their unique electronic structures,low conformation disorder,and excellent optoelectronic properties.Most all-fused-ring molecules are p-type organic semiconductors and possess medium bandgaps.In this work,we design and synthesize an all-fused-ring molecule(FM1)with an n-type property and narrow bandgap,which is a 10-fused-ring system composed of one electrondeficient benzotriazole core,two electron-rich thienopyrrole bridging units,and two electron-deficient malononitrile-functionalized end-cappers.FM1 exhibits low-lying highest occupied molecular orbit/lowest unoccupied molecular orbit energy levels of−5.77 eV/−3.89 eV,high electron mobility of 6.0×10^(−4)cm^(2)V^(−1)s^(−1),an optical bandgap of 1.50 eV,and a maximum absorption wavelength of 769nm.Because of the all-fused-ring skeleton,FM1 shows superior photostability and chemical stability.We use FM1 as an electron acceptor and successfully construct organic solar cell(OSC)devices with a decent power conversion efficiency(PCE)of 10.8%.Most importantly,the intrinsic stability of FM1 leads to its excellent OSC device stability.After irradiation with simulated solar light for 16 h,while control of the OSC device of the state-of-the-art small molecule electron acceptor shows a 46%decrease of PCE,the FM1’s unencapsulated OSC device exhibits only a 9%decrease of PCE.展开更多
A new fused-ring electron acceptor FNIC3 with dynamics controlled aggregation behavior was synthesized.FNIC3 shows strong absorption in 600–900 nm,HOMO/LUMO energy levels of−5.59/−4.04 eV,and electron mobility of 1.2...A new fused-ring electron acceptor FNIC3 with dynamics controlled aggregation behavior was synthesized.FNIC3 shows strong absorption in 600–900 nm,HOMO/LUMO energy levels of−5.59/−4.04 eV,and electron mobility of 1.2×10^(−3) cm^(2) V^(−1) s^(−1).The aggregation of FNIC3 shows strong dependency on film formation time.Prolongation of film formation time promotes the crystallization of FNIC3,leading to improved crystallinity and enlarged aggregate sizes.Aggregation of FNIC3 significantly influences the photovoltaic device parameters.Appropriate aggregation red-shifts the absorption and improves the mobilities of the blend,which contributes to high photocurrent and fill factor thus high power conversion efficiency(PCE).Overaggregation leads to increased nonradiative energy loss and insufficient charge generation,resulting in decreased open-circuit voltage and short-circuit current density.The blends based on PM6:FNIC3 fabricated under proper film formation time exhibit a PCE of 12.3%,higher than those fabricated under short and long film formation time(10.0–10.5%).展开更多
The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron a...The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron acceptor based on indacenodithiophene(IDIC)was for the first time introduced as a transition layer between a tin-based perovskite layer and a C 60 electron transport layer,leading to better matched energy levels in the device.In addition,coordination interactions between IDIC and perovskite improved the latter's crystallinity.The introduction of IDIC raised the power conversion efficiency from 8.98%to 11.5%and improved the device's stability.The decomposition mechanism of tin-based perovskite was also revealed by detecting the optical properties of perovskite microdomains through innovative integration of confocal laser scanning microscopy and photoluminescence spectroscopy.展开更多
Fluorophores emitting in the second near-infrared window (NIR-II, 900–1700nm) allow for high-resolution deep-tissue bioimaging owing to minimal tissue scattering. Although J-aggregation offers a promising approach to...Fluorophores emitting in the second near-infrared window (NIR-II, 900–1700nm) allow for high-resolution deep-tissue bioimaging owing to minimal tissue scattering. Although J-aggregation offers a promising approach to developing long-wavelength emitters, the scarcity of J-type backbones and reliable design principles limits their application in biological imaging. Here, we introduce a strategy for engineering high-brightness NIR-II J-aggregated fluorophores by incorporating electron-withdrawing substituents into a fused-ring backbone. These substituents modulate the electrostatic potential (ESP) distribution across the conjugated backbone, reducing both electrostatic repulsion and intermolecular distance, which promotes ordered J-aggregation. As a result, Y8 aggregate (Y8 nanoparticles) exhibits an outstanding fluorescence quantum yield of up to 12.9% and strong near-infrared absorption in aqueous solution for high-performance NIR-II fluorescence imaging in vivo. This work not only presents a novel J-type backbone but also advances the understanding of the structure–property relationship critical to designing NIR-II J-aggregates.展开更多
Four fused-benzotriazole based p-type polymers(BDT-TT,BDT-Se,BDD-TT,and BDD-Se)were designed and synthesized,and the fine-tuning on absorption band-widths and bandgaps via the backbone seleno-phene and thiophene strat...Four fused-benzotriazole based p-type polymers(BDT-TT,BDT-Se,BDD-TT,and BDD-Se)were designed and synthesized,and the fine-tuning on absorption band-widths and bandgaps via the backbone seleno-phene and thiophene strategies were reported.First,we introduced dithienothiophen[3,2-b]pyrrolobenzotriazole to co-polymerize with BDT-2F and synthesized BDT-TT.Then,we used selenophene to replace the thienothiophene units on the dithienothiophen[3,2-b]pyrrolobenzotriazole and synthesized BDT-Se.Compared to BDT-TT,BDT-Se showed a reduced bandgap from 2.0 eV to 1.89 eV.After that,we used BDD to replace BDT-2F and synthesized BDD-TT by co-polymerizing with dithienothiophen[3,2-b]pyrrolobenzotriazole.In comparison to BDT-TT,BDD-TT showed extended absorption band-width with the full-width-at-the-half-maximum(FWHM)increased from 138 nm to 229 nm and reduced bandgap from 2.0 eV to 1.71 eV.At last,we combined BDD and diselenophen[3,2-b]pyrrolo-benzotriazole and synthesized BDD-Se,which achieved extended absorption and further reduced bandgap(1.61 eV).Using PC71BM as the electron acceptor material,the organic solar cells fabricated by the four polymers gave the efficiencies of 1%-2%.展开更多
Balancing charge generation and low energy loss(E_(loss)), especially in the wide spectral absorption region is critical to obtain high-performance organic photovoltaics(OPVs). Therefore, Y11-M and Y11-EB are designed...Balancing charge generation and low energy loss(E_(loss)), especially in the wide spectral absorption region is critical to obtain high-performance organic photovoltaics(OPVs). Therefore, Y11-M and Y11-EB are designed and synthesized through modifying alkyl chains on different nitrogen aromatic rings of the reported non-fullerene acceptor Y11. Although all the molecules have almost similar low band-gap(around 1.30 e V), Y11-M and Y11-EB exhibit wider absorption in 410–870 nm region. Eventually, the conventional devices based on Y11-M and Y11-EB possess more efficient charge generation with low Eloss(around 0.44 e V). In addition, outstanding efficiencies of 16.64% and 17.15% with the fill factor of 76.15% and 74.73% are obtained in PM6:Y11-M and PM6:Y11-EB-based devices, both higher than Y11:PM6. The results highlight the importance of rational alkyl chains optimization, and a good structureproperty relationship is established as well.展开更多
Oligomeric electron acceptors have attracted increasing attention in organic solar cells(OSCs)for their high stability and low voltage losses,despite complex synthesis and poor solubility due to large conjugated syste...Oligomeric electron acceptors have attracted increasing attention in organic solar cells(OSCs)for their high stability and low voltage losses,despite complex synthesis and poor solubility due to large conjugated systems.In this work,a simple oligomer,DT-6IC based on a Y-series electron acceptor,has been developed to show excellent solubility,and hence can be used to tune the microstructure of the photoactive layer to achieve high-performance OSCs.DT-6IC is synthesized via one-step reaction between an electron-rich aromatic diamine based on Y-acceptor and hexaketocyclohexane to provide the key precursor,followed by two typical steps.Its“three-blade propeller”configuration,with each Y-acceptor forming a blade,results in highly twisted conjugated backbones,contributing to its high solubility.Additionally,DT-6IC exhibits cascade frontier energy levels with other donor polymer and Y-acceptors,high photoluminescence,and enhanced electron transport via the 3D structure.As a consequence,ternary OSCs based on DT-6IC as the third component provide a high efficiency of 19.04%,a substantial advancement over the 17.75%of binary OSCs.This work provides a simple synthetic method to obtain highly soluble oligomeric electron acceptors and demonstrates that these 3D twist acceptors have the great potential to realize high-performance OSCs.展开更多
Developing high-performance organic photodetectors(OPDs)with spectral responses over 1000 nm is of paramount importance to fundamental research and practical applications,yet effective approaches to achieve this remai...Developing high-performance organic photodetectors(OPDs)with spectral responses over 1000 nm is of paramount importance to fundamental research and practical applications,yet effective approaches to achieve this remain elusive.Herein,we develop ultranarrow bandgap electron acceptors through a theory-guided synergistic modification strategy.The optimal electron acceptor shows absorption over 1100 nm with smaller reorganization energies,more regulated crystallinity with a predominant face-on packing mode,and better miscibility with polymer donors,which affords the resultant OPDs with improved charge dissociation and transport,and favorable active layer morphology.The optimized OPDs have less charge recombination,energetic disorder,and trap density,showing ultralow dark current density(Jd)of 3.8×10^(-11)A cm^(-2),high shot-noise-limited specific detectivities(D*sh)over 1013 Jones in the range of 320-1100 nm,and an ultrafast response time below 0.3μs.Further incorporating a fullerene derivative(PC71BM)as the third component suppresses Jd to 2.3×10^(-11)A cm^(-2),resulting in prominent D*sh values of over 10^(14)Jones spanning from 640 to 1020 nm,with a peak value of 1.4×10^(14)Jones at 950 nm.This work not only provides cutting-edge performance in near-infrared(NIR)OPDs reported so far but also opens an intriguing materialdriven dimension to achieve sensitive OPDs for vis-to-NIR broadband photodetection.展开更多
Organic room-temperature phosphorescence(RTP)materials have attracted immense attention in bioimaging due to their long emission lifetime and large Stokes shift.RTP materials with long emission wavelength can improve ...Organic room-temperature phosphorescence(RTP)materials have attracted immense attention in bioimaging due to their long emission lifetime and large Stokes shift.RTP materials with long emission wavelength can improve the penetration depth for bioimaging.However,the design of red persistent RTP materials is still challenging.In this study,a fused-ring structure has been proposed to effectively decrease the triplet energy level,thus extending the emission wavelength of phosphorescence.In addition,the fused-ring structure exhibits a high molar extinction coefficient(ɛ)and high luminescence efficiency due to the rigid structure.A new class of crystalline hosts(iminodibenzyl,IDB)are developed to stabilize the triplet excitons that are generated from the fused-ring molecules.The maximum RTP wavelength of doping materials can reach 635 nm with a lifetime of 9.35 ms.Water-disperse nanoparticles are successfully prepared for in vivo time-resolved bioimaging,which eliminates the background fluorescence interference from biological tissues.These reveal a delicate design strategy for the construction of long-wavelength emissive RTP materials for high-resolution bioimaging.展开更多
Dimeric fused-ring electron acceptors(DFREAs)have attracted much attention due to the combined advantages of their monomeric and polymeric acceptors,including a well-defined molecular structure,excellent repeatability...Dimeric fused-ring electron acceptors(DFREAs)have attracted much attention due to the combined advantages of their monomeric and polymeric acceptors,including a well-defined molecular structure,excellent repeatability,and stable morphology.However,the additionally introduced single-bonds during dimerization may result in a twisted backbone of DFREAs,which is detrimental to intermolecular packing and charge transport.Herein,three DFREAs are designed and synthesized,in which DFREA conformations were systematically tuned via adjusting the intensities of intramolecular noncovalent interactions(INIs)to achieve high-performance organic solar cells(OSCs).Theoretical and experimental results show that the gradual introduction of S…F INIs can continuously improve molecular planarity and rigidity,resulting in reduced reorganization energies,ordered packing mode,and enhanced crystallization of DFREAs.Benefiting from the incorporation of fourfold S…F INIs,DYF-TF-based binary OSCs show a record high efficiency of 18.26%with an extremely low energy loss(0.493 eV)for DFREAbased OSCs.In addition,DYF-TF-based OSCs exhibited good long-term stability with a T_(80%)lifetime of 2681 h,and the power conversion efficiency of the DYF-TF-based ternary device is further enhanced to 18.73%.This contribution demonstrates the great potential of the INIs strategy in achieving excellent DFREAs materials.展开更多
An isomerism strategy was employed to develop single,end‐group bromine-substituted non‐fullerene two isomeric acceptors,2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e...An isomerism strategy was employed to develop single,end‐group bromine-substituted non‐fullerene two isomeric acceptors,2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2,"3′′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(4-bromo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)dimalononitrile(BTIC-2Br-β)and 2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2,"3′′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5-bromo-3-oxo-2,3-dihydro-1Hinden-1-ylidene)dimalononitrile(BTIC-2Br-γ).展开更多
Organic room-temperature phosphorescence(RTP)materials have been used in high-resolution imaging.However,the development of long-wavelength-emis sion RTP materials in aqueous solution remains a challenge.Here,we repor...Organic room-temperature phosphorescence(RTP)materials have been used in high-resolution imaging.However,the development of long-wavelength-emis sion RTP materials in aqueous solution remains a challenge.Here,we report red-emissive RTP materials via integration of the ring-fusing effect and host–vip interaction.展开更多
Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives...Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives through transition metal-catalyzed C—H activation/annulation was reported.3-Phenyl-2H-benzothiadiazine-1,1-dioxide was used as the reaction substrate,and vinylene carbonate and 4-diazopyrazolone were used as the coupling reagents,respectively.This strategy provides straightforward access to complex N-heterocycles in a highly efficient and simple manner.展开更多
Photo-induced electron transfer (PET) of silyl enol ethers has been employed to synthesize several fused ring systems. However, the method has limited applicability due to its narrow substrate scope, low product yield...Photo-induced electron transfer (PET) of silyl enol ethers has been employed to synthesize several fused ring systems. However, the method has limited applicability due to its narrow substrate scope, low product yields, unsatisfactory stereo- and regioselectivity. Herein, we report a PET-triggered cascade reaction of silyl enolates that leads to the formation of angularly fused tricyclic scaffolds. The reaction exhibits broad substrate scope and excellent stereoselectivity. The regio- and stereoselectivity of this cascade reaction is elucidated via DFT calculation and conformational analysis.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U21A20101 and 22105208)China Postdoctoral Science Foundation(No.2021M703263).
文摘We synthesize and compare four near-infrared absorbing fused-ring electron acceptors named as nTTIC(n=2,3,4,and 5),based on different number of thieno[3,2-b]thiophene(TT)unit as the electron-donating core.With increasing the TT unit,absorption spectrum of the TTIC series red shifts,and the highest occupied molecular orbital(HOMO)upshifts notably.It is worth noting that 4TTIC and 5TTIC exhibit absorption edges approaching 1100 nm,which is the photoresponse limit of solar cells based on crystal silicon.When the TTIC series acceptors are blended with polymer donor PM6,the binary-blend organic solar cells based on 3TTIC show the best power conversion efficiency(PCE)of 13.1%.In contrast,2TTIC-based devices exhibit relatively lower PCE of 8.32%,mainly caused by the larger energy loss and blue-shifted absorption.Due to insufficient driving force of charge separation caused by very high HOMO,4TTIC and 5TTIC show poor PCEs lower than 3%.
基金This work is supported by the National Natural Science Foundation of China(U21A20101).
文摘Fullerene derivatives are classic electron acceptor materials for organic solar cells (Oscs) but possess some intrinsic drawbacks such as weak visiblelightabsorption,limitedoptoelectronic property tunability,dificult purification and photochemical/morphological instability.Fullereneacceptors area bottleneck restricting further development of this field. Ourgroup pioneered the exploration of novel nonfulerene acceptors in China in 2006,andinitiated the research of two representative acceptor systems, rylene dimide polymer and fused-ring electron acceptor (FREA).FREA breaks the theoreticalefficiencylimit of fullerene-based OsCs (-13%) and promotes the whole field to an unprecedented prosperity with efficiency of 20%, heraldinga nonfullerene era for OsCs.In this review, we revisit 15-year nonfullerene exploration journey,summarize the design principles,molecular engineeringstrategies, physical mechanisms and device applications of these two nonfullerene acceptor systems, and propose some possible researchtopics in the nearfuture.
文摘We propose a strategy to improve performance of unidirectionally extended fused-ring electron acceptors by using pyrrolo[3,2-b]pyrrole to replace pyrrole ring, and design two asymmetric nonfullerene acceptors 1PIC and 2PIC. Replacing pyrrole in 1PIC with pyrrolo[3,2-b]pyrrole remarkably red-shifts absorption peak by 109 nm, elevates the HOMO and LUMO energy levels, and improves electron mobility. The photovoltaic devices based on blend of PM6 donor and 2PIC acceptor exhibit power conversion efficiency as high as 12.6%, which is much higher than that of PM6:1PIC (3.53%), due to more efficient exciton generation and dissociation, faster and more balanced carrier transport and less charge recombination.
基金supported by the National Natural Science Foundation of China (52103352, 52120105006, 21774130, 51925306)the National Key R&D Program of China (2018FYA 0305800)+1 种基金the Key Research Program of the Chinese Academy of Sciences (XDPB082)the Strategic Priority Research Program of Chinese Academy of Sciences (XDB28000000)。
文摘The polymerization of fused-ring acceptors(FRAs) to afford their corresponding polymeric acceptors for high-performance all-polymer solar cells(all-PSCs) has achieved remarkable progress in the past few years.However,due to the high degree of synthetic complexity for the monomer,the high-cost of these polymeric acceptors may limit their commercial applications.Thus,it is urgent to develop inexpensive and high-performance polymeric acceptors for all-PSCs.Herein,two novel polymeric acceptors(PBTzO and PBTzO-2F) have been designed and synthesized by copolymerization of noncovalently fused ring acceptors(NFRAs),which were employed in all-PSCs for the first time.Upon introducing the “noncovalently conformational locks(NoCLs)” in the backbone and selective fluorination of the end-group,photophysical and electrical properties,and solidstate packing properties of the NFRAs have been rationally tuned.As a result,the PBDB-T:PBTzO-2F based devices presented an excellent power conversion efficiency(PCE) of 11.04%,much higher than that of PBTzO based ones due to the increased charge generation and extraction,improved hole transfer and carrier mobilities,and reduced energy loss.More importantly,PBTzO-2F exhibited a much lower synthetic complexity(SC) index and higher figure-of-merit(FOM) values than the high-performance fused-ring acceptor based polymer acceptors(FRA-PAs) due to the simpler structures and more effective synthesis.This contribution provided a novel idea to achieve low-cost and high-performance all-PSCs.
基金Y.L.acknowledges financial supports from the National Natural Science Foundation of China(No.21772084)Fundamental Research Layout of Shenzhen(No.JCY20180504165657443)+2 种基金H.S.thanks the National Natural Science Foundation of China(Nos.11727810,61720106009 and 21603074)the Science and Technology Commission of Shanghai Municipality(No.19JC1412200)for funding support and the ECNU Multifunctional Platform for Innovation(001)and HPC Research Computing Team for providing computational and storage resourcesX.Z thanks the funding supports from the National Natural Science Foundation of China(Nos.91859101,81971744,and U1932107).
文摘It is challenging to develop molecular fluorophores in the second near-infrared(NIR-Ⅱ)window with long wavelength emission and high brightness,which can improve the performance of biological imaging.Herein,we report a molecular engineering approach to afford NIR-Ⅱ fluorophores with these merits based on fused-ring acceptor(FRA)molecules.Dioctyl 3,4-propylenedioxy thiophene(PDOT-C8)is utilized as the bridging donor to replace 3-ethylhexyloxy thiophene(3-EHOT),leading to more than 20 times enhancement of brightness.The nanofluorophores(NFs)based on the optimized CPTIC-4F molecule exhibit an emission peak of 1,110 nm with a fluorescence quantum yield(QY)of 0.39%(QY of IR-26 is 0.050%in dichloroethane as reference)and peak absorption coefficient of 14.5 x 10^4 M^-1·cm^-1 in aqueous solutions,which are significantly higher than those of 3-EHOT based COTIC-4F NFs.It is found that PDOT-C8 can weaken intermolecular aggregation,enhance protection of molecular backbone from water,and decrease backbone distortion,beneficial for the high brightness.Compared with indocyanine green with same injection dose,CPTIC-4F NFs show 10 times higher signal-to-background ratio for whole body vessels imaging at 1,300 nm long pass filters.
基金Natural Science Foundation for Distinguished Young Scholars of Guangdong Province,Grant/Award Number:2021B1515020027Science and Technology Projects in Guangzhou,Grant/Award Number:202201000002+4 种基金Shenzhen Science and Technology Innovation Commission,Grant/Award Numbers:JCYJ202103243104813035,JCYJ20180504165709042GuangDong Basic and Applied Basic Research Foundation,Grant/Award Number:2021A1515110892China Postdoctoral Science Foundation,Grant/Award Number:2021M700062Open Fund of the State Key Laboratory of Luminescent Materials and Devices,Grant/Award Number:2022-skllmd-17X.G.,H.S.,and Y.J.are thankful for the financial support from the Songshan Lake Materials Laboratory,Grant/Award Number:2021SLABFK03。
文摘The power conversion efficiencies(PCEs)of organic solar cells(OSCs)have improved considerably in recent years with the development of fused-ring electron acceptors(FREAs).Currently,FREAs-based OSCs have achieved high PCEs of over 19%in single-junction OSCs.Whereas the relatively high synthetic complexity and the low yield of FREAs typically result in high production costs,hindering the commercial application of OSCs.In contrast,noncovalently fused-ring electron acceptors(NFREAs)can compensate for the shortcomings of FREAs and facilitate large-scale industrial production by virtue of the simple structure,facile synthesis,high yield,low cost,and reasonable efficiency.At present,OSCs based on NFREAs have exceeded the PCEs of 15%and are expected to reach comparable efficiency as FREAs-based OSCs.Here,recent advances in NFREAs in this review provide insight into improving the performance of OSCs.In particular,this paper focuses on the effect of the chemical structures of NFREAs on the molecule conformation,aggregation,and packing mode.Various molecular design strategies,such as core,side-chain,and terminal group engineering,are presented.In addition,some novel polymer acceptors based on NFREAs for all-polymer OSCs are also introduced.In the end,the paper provides an outlook on developing efficient,stable,and low-cost NFREAs for achieving commercial applications.
基金support by the National Key Research and Development Program of China(grant no.2019YFA0705900)funded by MOST and the National Natural Science Foundation of China(grant nos.22135007 and 21875244).
文摘All-fused-ringπ-conjugated molecules have received considerable attention because of their unique electronic structures,low conformation disorder,and excellent optoelectronic properties.Most all-fused-ring molecules are p-type organic semiconductors and possess medium bandgaps.In this work,we design and synthesize an all-fused-ring molecule(FM1)with an n-type property and narrow bandgap,which is a 10-fused-ring system composed of one electrondeficient benzotriazole core,two electron-rich thienopyrrole bridging units,and two electron-deficient malononitrile-functionalized end-cappers.FM1 exhibits low-lying highest occupied molecular orbit/lowest unoccupied molecular orbit energy levels of−5.77 eV/−3.89 eV,high electron mobility of 6.0×10^(−4)cm^(2)V^(−1)s^(−1),an optical bandgap of 1.50 eV,and a maximum absorption wavelength of 769nm.Because of the all-fused-ring skeleton,FM1 shows superior photostability and chemical stability.We use FM1 as an electron acceptor and successfully construct organic solar cell(OSC)devices with a decent power conversion efficiency(PCE)of 10.8%.Most importantly,the intrinsic stability of FM1 leads to its excellent OSC device stability.After irradiation with simulated solar light for 16 h,while control of the OSC device of the state-of-the-art small molecule electron acceptor shows a 46%decrease of PCE,the FM1’s unencapsulated OSC device exhibits only a 9%decrease of PCE.
基金National Science Foundation of China,Grant/Award Numbers:51761165023,21734001。
文摘A new fused-ring electron acceptor FNIC3 with dynamics controlled aggregation behavior was synthesized.FNIC3 shows strong absorption in 600–900 nm,HOMO/LUMO energy levels of−5.59/−4.04 eV,and electron mobility of 1.2×10^(−3) cm^(2) V^(−1) s^(−1).The aggregation of FNIC3 shows strong dependency on film formation time.Prolongation of film formation time promotes the crystallization of FNIC3,leading to improved crystallinity and enlarged aggregate sizes.Aggregation of FNIC3 significantly influences the photovoltaic device parameters.Appropriate aggregation red-shifts the absorption and improves the mobilities of the blend,which contributes to high photocurrent and fill factor thus high power conversion efficiency(PCE).Overaggregation leads to increased nonradiative energy loss and insufficient charge generation,resulting in decreased open-circuit voltage and short-circuit current density.The blends based on PM6:FNIC3 fabricated under proper film formation time exhibit a PCE of 12.3%,higher than those fabricated under short and long film formation time(10.0–10.5%).
基金The authors gratefully acknowledge the financial support from the Beijing National Laboratory for Molecular Sciences and the National Natural Science Foundation of China(61935016 and 21771008)X.Z.thanks National Key Research and Development Program of China(2020YFB1506400).
文摘The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron acceptor based on indacenodithiophene(IDIC)was for the first time introduced as a transition layer between a tin-based perovskite layer and a C 60 electron transport layer,leading to better matched energy levels in the device.In addition,coordination interactions between IDIC and perovskite improved the latter's crystallinity.The introduction of IDIC raised the power conversion efficiency from 8.98%to 11.5%and improved the device's stability.The decomposition mechanism of tin-based perovskite was also revealed by detecting the optical properties of perovskite microdomains through innovative integration of confocal laser scanning microscopy and photoluminescence spectroscopy.
基金support from the National Natural Science Foundation of China (Nos. 62175201 and 52373142)the Natural Science Foundation of Jiangsu Province of China (No. BK20220404)+1 种基金the Fundamental Research Funds for the Central Universitiesthe open research fund of State Key Laboratory of Organic Electronics and Information Displays.
文摘Fluorophores emitting in the second near-infrared window (NIR-II, 900–1700nm) allow for high-resolution deep-tissue bioimaging owing to minimal tissue scattering. Although J-aggregation offers a promising approach to developing long-wavelength emitters, the scarcity of J-type backbones and reliable design principles limits their application in biological imaging. Here, we introduce a strategy for engineering high-brightness NIR-II J-aggregated fluorophores by incorporating electron-withdrawing substituents into a fused-ring backbone. These substituents modulate the electrostatic potential (ESP) distribution across the conjugated backbone, reducing both electrostatic repulsion and intermolecular distance, which promotes ordered J-aggregation. As a result, Y8 aggregate (Y8 nanoparticles) exhibits an outstanding fluorescence quantum yield of up to 12.9% and strong near-infrared absorption in aqueous solution for high-performance NIR-II fluorescence imaging in vivo. This work not only presents a novel J-type backbone but also advances the understanding of the structure–property relationship critical to designing NIR-II J-aggregates.
文摘Four fused-benzotriazole based p-type polymers(BDT-TT,BDT-Se,BDD-TT,and BDD-Se)were designed and synthesized,and the fine-tuning on absorption band-widths and bandgaps via the backbone seleno-phene and thiophene strategies were reported.First,we introduced dithienothiophen[3,2-b]pyrrolobenzotriazole to co-polymerize with BDT-2F and synthesized BDT-TT.Then,we used selenophene to replace the thienothiophene units on the dithienothiophen[3,2-b]pyrrolobenzotriazole and synthesized BDT-Se.Compared to BDT-TT,BDT-Se showed a reduced bandgap from 2.0 eV to 1.89 eV.After that,we used BDD to replace BDT-2F and synthesized BDD-TT by co-polymerizing with dithienothiophen[3,2-b]pyrrolobenzotriazole.In comparison to BDT-TT,BDD-TT showed extended absorption band-width with the full-width-at-the-half-maximum(FWHM)increased from 138 nm to 229 nm and reduced bandgap from 2.0 eV to 1.71 eV.At last,we combined BDD and diselenophen[3,2-b]pyrrolo-benzotriazole and synthesized BDD-Se,which achieved extended absorption and further reduced bandgap(1.61 eV).Using PC71BM as the electron acceptor material,the organic solar cells fabricated by the four polymers gave the efficiencies of 1%-2%.
基金support of the National Natural Science Foundation of China (21875286)the National Key Research and Development Program of China (2017YFA0206600)。
文摘Balancing charge generation and low energy loss(E_(loss)), especially in the wide spectral absorption region is critical to obtain high-performance organic photovoltaics(OPVs). Therefore, Y11-M and Y11-EB are designed and synthesized through modifying alkyl chains on different nitrogen aromatic rings of the reported non-fullerene acceptor Y11. Although all the molecules have almost similar low band-gap(around 1.30 e V), Y11-M and Y11-EB exhibit wider absorption in 410–870 nm region. Eventually, the conventional devices based on Y11-M and Y11-EB possess more efficient charge generation with low Eloss(around 0.44 e V). In addition, outstanding efficiencies of 16.64% and 17.15% with the fill factor of 76.15% and 74.73% are obtained in PM6:Y11-M and PM6:Y11-EB-based devices, both higher than Y11:PM6. The results highlight the importance of rational alkyl chains optimization, and a good structureproperty relationship is established as well.
基金supported by the Beijing Natural Science Foundation(grant nos.JQ21006 and 2212045)the National Natural Science Foundation of China(grant nos.92163128 and 52073016)+2 种基金supported by the Fundamental Research Funds for the Central Universities(grant nos.buctrc201828,XK1802-2,buctrc202111,and BH2313)L.Ding thanks the National Key Research and Development Program of China(2023YFE0116800)Beijing Natural Science Foundation(IS23037)for financial support.
文摘Oligomeric electron acceptors have attracted increasing attention in organic solar cells(OSCs)for their high stability and low voltage losses,despite complex synthesis and poor solubility due to large conjugated systems.In this work,a simple oligomer,DT-6IC based on a Y-series electron acceptor,has been developed to show excellent solubility,and hence can be used to tune the microstructure of the photoactive layer to achieve high-performance OSCs.DT-6IC is synthesized via one-step reaction between an electron-rich aromatic diamine based on Y-acceptor and hexaketocyclohexane to provide the key precursor,followed by two typical steps.Its“three-blade propeller”configuration,with each Y-acceptor forming a blade,results in highly twisted conjugated backbones,contributing to its high solubility.Additionally,DT-6IC exhibits cascade frontier energy levels with other donor polymer and Y-acceptors,high photoluminescence,and enhanced electron transport via the 3D structure.As a consequence,ternary OSCs based on DT-6IC as the third component provide a high efficiency of 19.04%,a substantial advancement over the 17.75%of binary OSCs.This work provides a simple synthetic method to obtain highly soluble oligomeric electron acceptors and demonstrates that these 3D twist acceptors have the great potential to realize high-performance OSCs.
基金the support from NSFC(grant nos.U21A20101,21875018,and 22305013)W.Liu also thanks the support from Fundamental Research Funds for the Central Universities(grant no.buctrc 202144).
文摘Developing high-performance organic photodetectors(OPDs)with spectral responses over 1000 nm is of paramount importance to fundamental research and practical applications,yet effective approaches to achieve this remain elusive.Herein,we develop ultranarrow bandgap electron acceptors through a theory-guided synergistic modification strategy.The optimal electron acceptor shows absorption over 1100 nm with smaller reorganization energies,more regulated crystallinity with a predominant face-on packing mode,and better miscibility with polymer donors,which affords the resultant OPDs with improved charge dissociation and transport,and favorable active layer morphology.The optimized OPDs have less charge recombination,energetic disorder,and trap density,showing ultralow dark current density(Jd)of 3.8×10^(-11)A cm^(-2),high shot-noise-limited specific detectivities(D*sh)over 1013 Jones in the range of 320-1100 nm,and an ultrafast response time below 0.3μs.Further incorporating a fullerene derivative(PC71BM)as the third component suppresses Jd to 2.3×10^(-11)A cm^(-2),resulting in prominent D*sh values of over 10^(14)Jones spanning from 640 to 1020 nm,with a peak value of 1.4×10^(14)Jones at 950 nm.This work not only provides cutting-edge performance in near-infrared(NIR)OPDs reported so far but also opens an intriguing materialdriven dimension to achieve sensitive OPDs for vis-to-NIR broadband photodetection.
基金the National Natural Scientific Foundation of China(Grant Nos.22222501,21975021,21975020,21875019,22105019,and 22175023)supported by Beijing National Laboratory for Molecular Sciences(BNLMS202007)the BIT Research and Innovation Promoting Project(2022YCXZ035).
文摘Organic room-temperature phosphorescence(RTP)materials have attracted immense attention in bioimaging due to their long emission lifetime and large Stokes shift.RTP materials with long emission wavelength can improve the penetration depth for bioimaging.However,the design of red persistent RTP materials is still challenging.In this study,a fused-ring structure has been proposed to effectively decrease the triplet energy level,thus extending the emission wavelength of phosphorescence.In addition,the fused-ring structure exhibits a high molar extinction coefficient(ɛ)and high luminescence efficiency due to the rigid structure.A new class of crystalline hosts(iminodibenzyl,IDB)are developed to stabilize the triplet excitons that are generated from the fused-ring molecules.The maximum RTP wavelength of doping materials can reach 635 nm with a lifetime of 9.35 ms.Water-disperse nanoparticles are successfully prepared for in vivo time-resolved bioimaging,which eliminates the background fluorescence interference from biological tissues.These reveal a delicate design strategy for the construction of long-wavelength emissive RTP materials for high-resolution bioimaging.
基金support from the National Nature Science Foundation of China(grant nos.51925306,52103352,52120105006)National Key R&D Program of China(grant no.2018FYA 0305800)+3 种基金Key Research Program of Chinese Academy of Sciences(grant no.XDPB08-2)the Strategic Priority Research Program of Chinese Academy of Sciences(grant no.XDB28000000)the Youth Innovation Promotion Association of Chinese Academy of Sciences(grant no.2022165)the Fundamental Research Funds for the Central Universities.DFT results described in this article were obtained from the National Supercomputing Center in Shenzhen(Shenzhen Cloud Computing Center).
文摘Dimeric fused-ring electron acceptors(DFREAs)have attracted much attention due to the combined advantages of their monomeric and polymeric acceptors,including a well-defined molecular structure,excellent repeatability,and stable morphology.However,the additionally introduced single-bonds during dimerization may result in a twisted backbone of DFREAs,which is detrimental to intermolecular packing and charge transport.Herein,three DFREAs are designed and synthesized,in which DFREA conformations were systematically tuned via adjusting the intensities of intramolecular noncovalent interactions(INIs)to achieve high-performance organic solar cells(OSCs).Theoretical and experimental results show that the gradual introduction of S…F INIs can continuously improve molecular planarity and rigidity,resulting in reduced reorganization energies,ordered packing mode,and enhanced crystallization of DFREAs.Benefiting from the incorporation of fourfold S…F INIs,DYF-TF-based binary OSCs show a record high efficiency of 18.26%with an extremely low energy loss(0.493 eV)for DFREAbased OSCs.In addition,DYF-TF-based OSCs exhibited good long-term stability with a T_(80%)lifetime of 2681 h,and the power conversion efficiency of the DYF-TF-based ternary device is further enhanced to 18.73%.This contribution demonstrates the great potential of the INIs strategy in achieving excellent DFREAs materials.
基金supported by the National Natural Science Foundation of China(nos.51773087,21733005,and 21975115)Shenzhen Fundamental Research Program(nos.JCYJ20170817111214740,JCYJ20180302180238419,and KQJSCX20180319114442157),and Shenzhen Nobel Prize Scientists Laboratory Project(no.C17213101)and the Guangdong Innovative and Entrepreneurial Research Team Program under contract no.2016ZT06G587.
文摘An isomerism strategy was employed to develop single,end‐group bromine-substituted non‐fullerene two isomeric acceptors,2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2,"3′′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(4-bromo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)dimalononitrile(BTIC-2Br-β)and 2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2,"3′′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5-bromo-3-oxo-2,3-dihydro-1Hinden-1-ylidene)dimalononitrile(BTIC-2Br-γ).
基金supported by the National Natural Scientific Foundation of China(grant nos.21975021,51803009,21905021,51673024,21975020,and 21875019)supported by Beijing National Laboratory for Molecular Sciences(no.BNLMS202007),China Postdoctoral Science Foundation 2019TQ0034.
文摘Organic room-temperature phosphorescence(RTP)materials have been used in high-resolution imaging.However,the development of long-wavelength-emis sion RTP materials in aqueous solution remains a challenge.Here,we report red-emissive RTP materials via integration of the ring-fusing effect and host–vip interaction.
基金Sichuan Science and Technology Program(No:2020YJ0221)the Natural Science Foundation of Shandong Province,China(No.ZR2021QH362).
文摘Comprehensive Summary Benzothiadiazine-1,1-dioxide scaffold is bioactive framework with wild utility and applications.Synthesis of benzothiadiazine-fused isoquinoline derivatives and spiro benzothiadiazine derivatives through transition metal-catalyzed C—H activation/annulation was reported.3-Phenyl-2H-benzothiadiazine-1,1-dioxide was used as the reaction substrate,and vinylene carbonate and 4-diazopyrazolone were used as the coupling reagents,respectively.This strategy provides straightforward access to complex N-heterocycles in a highly efficient and simple manner.
基金supported by NSFC(21925106,U19A2014)Si-chuan University(2020SCUNL204)Department of Science and Technology of Sichuan Province(2023NSFSC0105).
文摘Photo-induced electron transfer (PET) of silyl enol ethers has been employed to synthesize several fused ring systems. However, the method has limited applicability due to its narrow substrate scope, low product yields, unsatisfactory stereo- and regioselectivity. Herein, we report a PET-triggered cascade reaction of silyl enolates that leads to the formation of angularly fused tricyclic scaffolds. The reaction exhibits broad substrate scope and excellent stereoselectivity. The regio- and stereoselectivity of this cascade reaction is elucidated via DFT calculation and conformational analysis.
