Organic solar cell(OSC)has attracted great interests due to its potential applications[1-9].To date,18%power conversion efficiency(PCE)has been achieved in single-junction OSC[10−13],indicating the feasibility of comm...Organic solar cell(OSC)has attracted great interests due to its potential applications[1-9].To date,18%power conversion efficiency(PCE)has been achieved in single-junction OSC[10−13],indicating the feasibility of commercialization.This photovoltaic technology currently faces the performance gap between laboratory cells and large-area modules.展开更多
Organic photothermal materials based on conjugated structures hold great potential for solar harvesting but are often constrained by narrow absorption and limited solar-thermal conversion efficiency.A general molecula...Organic photothermal materials based on conjugated structures hold great potential for solar harvesting but are often constrained by narrow absorption and limited solar-thermal conversion efficiency.A general molecular design strategy that can simultaneously broaden absorption and enhance nonradiative decay remains elusive.Here,we pioneer a quinoid-donor-acceptor(Q-D-A)architecture specifically tailored for photothermal applications.Incorporating quinoidal unit into a D-A polymer backbone yields the novel polymer PAQM-TBz,which exhibits a reinforced backbone planarity,intensifiedπ-πinteractions,and enhanced diradical character compared with its D-A analogue,P2T-TBz.These synergistic features enable broadband absorption(400-1500 nm)and rapid nonradiative relaxation,yielding an outstanding photothermal conversion efficiency of 80.6%under 808 nm laser irradiation—nearly twice that of P2T-TBz.Under 1.0 kW m^(-2) simulated sunlight,PAQM-TBz achieves a record-high solar-to-vapor efficiency of 97.3%with an evaporation rate of 1.41 kg m^(-2) h^(-1).It also generates a peak thermoelectric voltage of 126.1 mV,and in integrated water-electricity cogeneration,attains an evaporation rate of 1.28 kg m^(-2) h^(-1) and a voltage 95.8 mV,ranking among the highest for organic materials.This work establishes the Q-D-A strategy as a transformative platform for advanced solar-thermal energy conversion and multifunctional solar-harvesting applications.展开更多
Organic solar cells(OSCs)have attracted significant attention as next-generation photovoltaics due to their unique advantages such as mechanical flexibility,lightweight,and solution processability.While state-of-the-a...Organic solar cells(OSCs)have attracted significant attention as next-generation photovoltaics due to their unique advantages such as mechanical flexibility,lightweight,and solution processability.While state-of-the-art power conversion efficiencies(PCEs)exceeding 20%are achieved in inert atmospheres,ambient processing remains a critical challenge for scalable production.Particularly detrimental is moisture penetration into the active layer,which induces a cascade of deleterious effects including trap state formation,charge carrier mobility imbalance,enhanced nonradiative recombination,and disruption of crystalline ordering,ultimately leading to severe device performance losses.Addressing these challenges necessitates strategic molecular engineering to enhance intrinsic moisture resistance by incorporating functional side chains into donor and acceptor materials and using small-molecule additives that suppress water condensation,stabilize morphology,and maintain efficient charge transport.This review systematically summarizes recent progress in the field of humiditytolerant ambient-processed OSCs.Donor:acceptor systems are categorized according to the reported processing humidity levels,including unspecified conditions,low humidity(RH<40%),moderate humidity(RH=40−70%),and high humidity(RH>70%).Encouragingly,even under 90%RH,some systems achieve the PCEs over 18%,demonstrating significant progress toward airprocessed OSCs with high humidity tolerance.These advancements highlight the great promise of molecular engineering strategies to enable the scalable fabrication of high-performance OSCs under ambient conditions with enhanced humidity tolerance.展开更多
Thiophene and its derivatives have garnered substantial interest in the organic electronics sector,particularly in the development of polymer solar cells(PSCs).Herein,we present the synthesis of a new thiophene deriva...Thiophene and its derivatives have garnered substantial interest in the organic electronics sector,particularly in the development of polymer solar cells(PSCs).Herein,we present the synthesis of a new thiophene derivative,ClE-T,by a simple two-step method,comprising a monothiophene functionalized with a chlorine atom and an ester group.The ClE-T offers unique benefits resulting from the combination of the two groups.The incorporation of ClE-T into a polymer yields a polymer donor poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-chloro-4-(methoxycarbonyl)-2,5-thiophenediyl]](PBDT-ClET).ClE-T demonstrates synergistic effects that significantly downshift energy levels and enhance the crystallinity of PBDT-ClET.In conclusion,PBDT-ClET is incorporated as a third component in all-polymer solar cells(all-PSCs)to enhance charge transport,reduce energy loss,and achievemore favorable phase separation.Finally,the all-PSCs employing PBDT-ClET achieve a notable power conversion efficiency(PCE)of 19.04%,which is not only among the highest values in all-PSCs but also represents the record PCE achieved for eco-friendly all-PSCs.This work underscores the promising potential of the ClE-T unit as a building block for constructing easily synthesized polymers for high-performance PSCs.展开更多
Nonfullerene-based organic solar cells(NFOSCs)have received great interest recently due to their higher performance and greater potential compared with fullerene-based solar cells[1].Power conversion efficiencies(PCEs...Nonfullerene-based organic solar cells(NFOSCs)have received great interest recently due to their higher performance and greater potential compared with fullerene-based solar cells[1].Power conversion efficiencies(PCEs)over 13% have been realized in single-junction NFOSCs[2].Compared with traditional fullerene acceptors,the greatest advantage of nonfullerene acceptors is their stronger light-harvesting capability in the visible and展开更多
Biomimetic superhydrophobic(SH)coatings have emerged as a promising alternative to traditional room temperature vulcanizing(RTV)silicone rubber coatings for improving the flashover strength of insulators.However,organ...Biomimetic superhydrophobic(SH)coatings have emerged as a promising alternative to traditional room temperature vulcanizing(RTV)silicone rubber coatings for improving the flashover strength of insulators.However,organic contamination occurs in outdoor applications and thus a superamphiphobic(SAP)surface is more desirable but not yet reported for improving flashover performance.Herein,we developed a novel anti-flashover technique by fabricating robust SAP coating with unique gradient and micro-nanoscale hierarchical architecture.The SAP coating was fabricated by sequentially spray-depositing a resin-based primer and a silica-based topcoat on substrates(i.e.,glass slides and insulators).The primer not only functions as an adhesive offering strong adhesion to the substrate but also offers a micromastoid-like structure facilitating the subsequent formation of hierarchical micro-nanostructure.The appropriate spraying pressure leads to a diffusion of the fluorocarbon-modified silica nanoparticles into the primer to form a unique gradient structure,by analogy to inserting bullets into a wood.These features render the SAP coating excellent robustness with strong abrasive resistance,excellent ultraviolet(UV)resistance,and excellent chemical and thermal stability.Pollution flashover property of the SAP coating was explored and compared with that of SH and RTV specimens,from which a novel organic-contamination model to evaluate the flashover performance was proposed.The coated SAP glass insulator demonstrated 42.9%pollution flashover voltage improvement than RTV-coated insulator.These stated unique features reveal the convincing potential of the present SAP coatings to be applied for not only outdoor transmission line insulators for antiflashover but also other fields for self-cleaning,anti-fouling,and anti-icing.展开更多
Towards a good control of the morphology of bulk-heterojunction(BHJ)active layers for polymer solar cells(PSCs),selecting an appropriate side chain for a polymer donor and a nonfullerene acceptor(NFA)is very crucial.I...Towards a good control of the morphology of bulk-heterojunction(BHJ)active layers for polymer solar cells(PSCs),selecting an appropriate side chain for a polymer donor and a nonfullerene acceptor(NFA)is very crucial.In this work,two novel NFAs i-IE-4F and i-IESi-4 F comprising alkyl and siloxane-terminated side chains on the central indacenodithiophene(IDT)core,respectively,were synthesized.Attaching the siloxane-terminated side chain to i-IESi-4 F affords surface energy(γ)of33.32 mN/m,much lower than that of 39.83 mN/m for i-IE-4F,supplying a big chance to tune miscibility with a polymer donor.Two fluorobenzotriazole-based polymer donors J52 and PBZ-2Si bearing alkyl and siloxane-terminated side chains,respectively,showγvalues of 36.08 and 33.10 mN/m,respectively.The estimated Flory-Huggins interaction parameters(χD,A)indicate that the i-IESi-4 F is more miscible than i-IE-4F in pairing with J52 or PBZ-2Si.The resulting i-IESi-4 F-based blend film exhibits low film roughness and accompanies obviously improved BHJ uniformity.In PSCs,the J52:i-IESi-4F and PBZ-2Si:i-IESi-4 F active layers display power conversion efficiencies(PCEs)of 12.67%and 14.54%,respectively,all remarkably higher than PCEs≤7.34%of the i-IE-4F-based active layers.Interestingly,the PBZ-2Si:i-IESi-4 F active layer,a donor:acceptor blend system comprising siloxane-terminated side chains(DSi:ASimatching)with the highest BHJ miscibility due to the combinatory effect of the side chains,shows the highest efficiency,as supported by efficient exciton dissociation,the lowest bimolecular recombination,and the optimal charge transport.Our results demonstrate that attaching siloxane-terminated side chains to NFAs,as a side chain engineering,has big potential in lowering their surface energy towards fine control of BHJ morphology and leading to a better donor:acceptor blend system.展开更多
Two new conjugated copolymers, PBDT-T6-TTF and PBDT-T12-TTF, were derived from a novel 4-fluorobenzoyl thienothi- ophene （TTF）. In addition, two types of benzodithiophene （BDT） units with 2,3-dihexylthienyl （T6）...Two new conjugated copolymers, PBDT-T6-TTF and PBDT-T12-TTF, were derived from a novel 4-fluorobenzoyl thienothi- ophene （TTF）. In addition, two types of benzodithiophene （BDT） units with 2,3-dihexylthienyl （T6） and 2,3-didodecylthienyl （T12） substituents, respectively, were successfully synthesized. The effect of the dual two-dimensional （2D） substitutions of the building blocks upon the optoelectronic properties of the polymers was investigated. Generally, the two polymers exhibited good solubility and broad absorption, showing similar optical band gaps of ~1.53 eV. However, PBDT-T6-TTF with its shorter alkyl chain length possessed a larger extinction coefficient in thin solid film. The highest occupied molecular orbital （HOMO） level of PBDT-T6-TTF was located at -5.38 eV while that of PBDT-T12-TTF was at -5.51 eV. In space charge-limited- current （SCLC） measurement, PBDT-T6-TTF and PBDT-T12-TTF displayed respective hole mobilities of 3.0~10-~ and 1.6x10 5 cm2 V-1 s-l. In polymer solar cells, PBDT-T6-TTF and PBDT-T12-TTF showed respective power conversion efficiencies （PCEs） of 2.86% and 1.67%. When 1,8-diiodooctane （DIO） was used as the solvent additive, the PCE of PBDT-T6-TTF was remarkably elevated to 4.85%, but the use of DIO for the PBDT-T12-TTF-blend film resulted in a lower PCE of 0.91%. Atomic force microscopy （AFM） indicated that the superior efficiency of PBDT-T6-TTF with 3% DIO （v/v） should be related to the better continuous phase separation of the blend film. Nevertheless, the morphology of the PBDT-T12-TTF deteriorated when the 3% DIO （v/v） was added. Our results suggest that the alkyl-chain length on the 2D BDT units play an important role in determining the optoelectronic properties of dual 2D BDT-TT-based polymers.展开更多
A series of novel acceptor-pended conjugated polymers featuring a newly developed carbazole-derived unit are designed and synthesized. The relationships between chemical structure and optoelectronic properties of the ...A series of novel acceptor-pended conjugated polymers featuring a newly developed carbazole-derived unit are designed and synthesized. The relationships between chemical structure and optoelectronic properties of the polymers are systematically in-vestigated. The control of UV-Vis absorption spectra and energy levels in resulting polymers are achieved by introducing suitable pended acceptor units. The photovoltaic properties of the resulting polymers are evaluated by blending the polymers with （6,6）-phenyl-CTFbutyric acid methyl ester. The resulting solar cells exhibit moderate performances with high open-circuit voltage. Charge transport properties and morphology were investigated to understand the performance of corresponding solar cells.展开更多
In this work, a new A-D-A type nonfuUerene small molecular acceptor SilDT-IC, with a fused-ring silaindacenodithiophene （SilDT） as D unit and 2-（3-oxo-2,3-dihydroinden-l-ylidene）malononitrile （INCN） as the end A...In this work, a new A-D-A type nonfuUerene small molecular acceptor SilDT-IC, with a fused-ring silaindacenodithiophene （SilDT） as D unit and 2-（3-oxo-2,3-dihydroinden-l-ylidene）malononitrile （INCN） as the end A unit, was design and synthesized. The SilDT-IC film shows absorption peak and edge at 695 and 733 nm, respectively. The HOMO and LUMO of SilDT-IC are of -5.47 and -3.78 eV, respectively. Compared with carbon-bridging, the Si-bridging can result in an upper-lying LUMO level of an acceptor, which is benefit to achieve a higher open-circuit voltage in polymer solar cells （PSCs）. Complementary absorption and suitable energy level alignment between SilDT-IC and wide bandgap polymer donor PBDB-T were found. For the PBDB-T：SilDT-IC based inverted PSCs, a D/A ratio of 1 ： 1 was optimal to achieve a power conversion efficiency （PCE） of 7.27%. With thermal annealing （TA） of the blend film, a higher PCE of 8.16% could be realized due to increasing of both short-circuit current density and fill factor. After the TA treatment, hole and electron mobilities were elevated to 3.42 × 10-4 and 1.02 × 10-4 cm2·V-1.s-1, respectively. The results suggest that the SilDT, a Si-bridged fused ring, is a valuable D unit to construct efficient nonfullerene acceptors for PSCs.展开更多
基金The authors thank National Natural Science Foundation of China(61774077,61804065,51673070,51521002,21704082,21875182,21534003,61705090 and 51320105014)National Key Research and Development Program of China(2016YFA0200700)+6 种基金China Postdoctoral Science Foundation(2017M623162),111 Project 2.0(BP2018008)the Basic and Applied Basic Research Fund of Guangdong Province(2019B1515120073)the Research and Development Program in Key Areas of Guangdong Province(2019B090921002 and 2019B010132004)the Fundamental Research Funds for the Central Universities(21618308)the State Key Laboratory of Luminescent Materials and Devices(2019-skllmd-05)the Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials Open Fund(KFVE20200006)for financial support.L.Ding thanks the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,and 21961160720)for financial support.
文摘Organic solar cell(OSC)has attracted great interests due to its potential applications[1-9].To date,18%power conversion efficiency(PCE)has been achieved in single-junction OSC[10−13],indicating the feasibility of commercialization.This photovoltaic technology currently faces the performance gap between laboratory cells and large-area modules.
基金supported by the National Natural Science Foundation of China(52363021 and 22305050)Science and Technology Foundation of Guizhou Province(QKHJC-ZK[2024]Key 002).
文摘Organic photothermal materials based on conjugated structures hold great potential for solar harvesting but are often constrained by narrow absorption and limited solar-thermal conversion efficiency.A general molecular design strategy that can simultaneously broaden absorption and enhance nonradiative decay remains elusive.Here,we pioneer a quinoid-donor-acceptor(Q-D-A)architecture specifically tailored for photothermal applications.Incorporating quinoidal unit into a D-A polymer backbone yields the novel polymer PAQM-TBz,which exhibits a reinforced backbone planarity,intensifiedπ-πinteractions,and enhanced diradical character compared with its D-A analogue,P2T-TBz.These synergistic features enable broadband absorption(400-1500 nm)and rapid nonradiative relaxation,yielding an outstanding photothermal conversion efficiency of 80.6%under 808 nm laser irradiation—nearly twice that of P2T-TBz.Under 1.0 kW m^(-2) simulated sunlight,PAQM-TBz achieves a record-high solar-to-vapor efficiency of 97.3%with an evaporation rate of 1.41 kg m^(-2) h^(-1).It also generates a peak thermoelectric voltage of 126.1 mV,and in integrated water-electricity cogeneration,attains an evaporation rate of 1.28 kg m^(-2) h^(-1) and a voltage 95.8 mV,ranking among the highest for organic materials.This work establishes the Q-D-A strategy as a transformative platform for advanced solar-thermal energy conversion and multifunctional solar-harvesting applications.
基金financial support of the National Natural Science Foundation of China(22179040)the Basic and Applied Basic Research Major Program of Guangdong Province(2019B030302007)the Guangdong Basic and Applied Basic Research Foundation(2024A1515012693).
文摘Organic solar cells(OSCs)have attracted significant attention as next-generation photovoltaics due to their unique advantages such as mechanical flexibility,lightweight,and solution processability.While state-of-the-art power conversion efficiencies(PCEs)exceeding 20%are achieved in inert atmospheres,ambient processing remains a critical challenge for scalable production.Particularly detrimental is moisture penetration into the active layer,which induces a cascade of deleterious effects including trap state formation,charge carrier mobility imbalance,enhanced nonradiative recombination,and disruption of crystalline ordering,ultimately leading to severe device performance losses.Addressing these challenges necessitates strategic molecular engineering to enhance intrinsic moisture resistance by incorporating functional side chains into donor and acceptor materials and using small-molecule additives that suppress water condensation,stabilize morphology,and maintain efficient charge transport.This review systematically summarizes recent progress in the field of humiditytolerant ambient-processed OSCs.Donor:acceptor systems are categorized according to the reported processing humidity levels,including unspecified conditions,low humidity(RH<40%),moderate humidity(RH=40−70%),and high humidity(RH>70%).Encouragingly,even under 90%RH,some systems achieve the PCEs over 18%,demonstrating significant progress toward airprocessed OSCs with high humidity tolerance.These advancements highlight the great promise of molecular engineering strategies to enable the scalable fabrication of high-performance OSCs under ambient conditions with enhanced humidity tolerance.
基金supported National Natural Science Foundation of China(grant nos.52422313,52173172,and 52173171)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences(grant no.PPCL2023-15)+7 种基金supported by University Students’Innovation Training Program(grant no.XJ202311078037)the Department of Education of Guangdong Province(grant no.2023KSY008)Research project of Guangzhou University(grant nos.RC2023030 and YJ2023052)the Department of Education of Guangdong Province(grant no.2023KSY008)Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(grant no.202255464)the Research&Development Projects in Key Areas of Guangdong Province,China(grant no.2019B010933001)supported by the Center for Computational Science and Engineering at the Southern University of Science and Technologysupport from the National Research Foundation of Korea(grant nos.2019R1A6A1A11044070 and 2020M3H4A3081814).
文摘Thiophene and its derivatives have garnered substantial interest in the organic electronics sector,particularly in the development of polymer solar cells(PSCs).Herein,we present the synthesis of a new thiophene derivative,ClE-T,by a simple two-step method,comprising a monothiophene functionalized with a chlorine atom and an ester group.The ClE-T offers unique benefits resulting from the combination of the two groups.The incorporation of ClE-T into a polymer yields a polymer donor poly[[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-chloro-4-(methoxycarbonyl)-2,5-thiophenediyl]](PBDT-ClET).ClE-T demonstrates synergistic effects that significantly downshift energy levels and enhance the crystallinity of PBDT-ClET.In conclusion,PBDT-ClET is incorporated as a third component in all-polymer solar cells(all-PSCs)to enhance charge transport,reduce energy loss,and achievemore favorable phase separation.Finally,the all-PSCs employing PBDT-ClET achieve a notable power conversion efficiency(PCE)of 19.04%,which is not only among the highest values in all-PSCs but also represents the record PCE achieved for eco-friendly all-PSCs.This work underscores the promising potential of the ClE-T unit as a building block for constructing easily synthesized polymers for high-performance PSCs.
基金supported by the National Natural Science Foundation of China (U1401244, 21374025,21372053,21572041,and 51503050)the National Key Research and Development Program of China (2017YFA0206600)+2 种基金the State Key Laboratory of Luminescent Materials and Devices(2016-skllmd-05)the Youth Association for Promoting Innovation(CAS)the U.S.Office of Naval Research(N00014-15-1-2244)for financial support
文摘Nonfullerene-based organic solar cells(NFOSCs)have received great interest recently due to their higher performance and greater potential compared with fullerene-based solar cells[1].Power conversion efficiencies(PCEs)over 13% have been realized in single-junction NFOSCs[2].Compared with traditional fullerene acceptors,the greatest advantage of nonfullerene acceptors is their stronger light-harvesting capability in the visible and
基金the project“Synthesis and Application of Superhydrophobic Self-cleaning Materials for Electric Engineering”(No.6111901321)Overseas Expertise Introduction Project(111 project)for Discipline Innovation of China(No.B18038)the State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)Open Foundation(No.SYSJJ2021-02).
文摘Biomimetic superhydrophobic(SH)coatings have emerged as a promising alternative to traditional room temperature vulcanizing(RTV)silicone rubber coatings for improving the flashover strength of insulators.However,organic contamination occurs in outdoor applications and thus a superamphiphobic(SAP)surface is more desirable but not yet reported for improving flashover performance.Herein,we developed a novel anti-flashover technique by fabricating robust SAP coating with unique gradient and micro-nanoscale hierarchical architecture.The SAP coating was fabricated by sequentially spray-depositing a resin-based primer and a silica-based topcoat on substrates(i.e.,glass slides and insulators).The primer not only functions as an adhesive offering strong adhesion to the substrate but also offers a micromastoid-like structure facilitating the subsequent formation of hierarchical micro-nanostructure.The appropriate spraying pressure leads to a diffusion of the fluorocarbon-modified silica nanoparticles into the primer to form a unique gradient structure,by analogy to inserting bullets into a wood.These features render the SAP coating excellent robustness with strong abrasive resistance,excellent ultraviolet(UV)resistance,and excellent chemical and thermal stability.Pollution flashover property of the SAP coating was explored and compared with that of SH and RTV specimens,from which a novel organic-contamination model to evaluate the flashover performance was proposed.The coated SAP glass insulator demonstrated 42.9%pollution flashover voltage improvement than RTV-coated insulator.These stated unique features reveal the convincing potential of the present SAP coatings to be applied for not only outdoor transmission line insulators for antiflashover but also other fields for self-cleaning,anti-fouling,and anti-icing.
基金supported by the National Natural Science Foundation of China(51521002,U1401244,51673070)the National Key Research and Development Program of China(2019YFA0705900)the Basic and Applied Basic Research Major Program of Guangdong Province(2019B030302007)。
文摘Towards a good control of the morphology of bulk-heterojunction(BHJ)active layers for polymer solar cells(PSCs),selecting an appropriate side chain for a polymer donor and a nonfullerene acceptor(NFA)is very crucial.In this work,two novel NFAs i-IE-4F and i-IESi-4 F comprising alkyl and siloxane-terminated side chains on the central indacenodithiophene(IDT)core,respectively,were synthesized.Attaching the siloxane-terminated side chain to i-IESi-4 F affords surface energy(γ)of33.32 mN/m,much lower than that of 39.83 mN/m for i-IE-4F,supplying a big chance to tune miscibility with a polymer donor.Two fluorobenzotriazole-based polymer donors J52 and PBZ-2Si bearing alkyl and siloxane-terminated side chains,respectively,showγvalues of 36.08 and 33.10 mN/m,respectively.The estimated Flory-Huggins interaction parameters(χD,A)indicate that the i-IESi-4 F is more miscible than i-IE-4F in pairing with J52 or PBZ-2Si.The resulting i-IESi-4 F-based blend film exhibits low film roughness and accompanies obviously improved BHJ uniformity.In PSCs,the J52:i-IESi-4F and PBZ-2Si:i-IESi-4 F active layers display power conversion efficiencies(PCEs)of 12.67%and 14.54%,respectively,all remarkably higher than PCEs≤7.34%of the i-IE-4F-based active layers.Interestingly,the PBZ-2Si:i-IESi-4 F active layer,a donor:acceptor blend system comprising siloxane-terminated side chains(DSi:ASimatching)with the highest BHJ miscibility due to the combinatory effect of the side chains,shows the highest efficiency,as supported by efficient exciton dissociation,the lowest bimolecular recombination,and the optimal charge transport.Our results demonstrate that attaching siloxane-terminated side chains to NFAs,as a side chain engineering,has big potential in lowering their surface energy towards fine control of BHJ morphology and leading to a better donor:acceptor blend system.
基金financially supported by the National Natural Science Foundation of China(21225418 and 51173048)the National Basic Research Program of China(2013CB834705 and 2014CB643505)GDUPS(2013)
文摘Two new conjugated copolymers, PBDT-T6-TTF and PBDT-T12-TTF, were derived from a novel 4-fluorobenzoyl thienothi- ophene （TTF）. In addition, two types of benzodithiophene （BDT） units with 2,3-dihexylthienyl （T6） and 2,3-didodecylthienyl （T12） substituents, respectively, were successfully synthesized. The effect of the dual two-dimensional （2D） substitutions of the building blocks upon the optoelectronic properties of the polymers was investigated. Generally, the two polymers exhibited good solubility and broad absorption, showing similar optical band gaps of ~1.53 eV. However, PBDT-T6-TTF with its shorter alkyl chain length possessed a larger extinction coefficient in thin solid film. The highest occupied molecular orbital （HOMO） level of PBDT-T6-TTF was located at -5.38 eV while that of PBDT-T12-TTF was at -5.51 eV. In space charge-limited- current （SCLC） measurement, PBDT-T6-TTF and PBDT-T12-TTF displayed respective hole mobilities of 3.0~10-~ and 1.6x10 5 cm2 V-1 s-l. In polymer solar cells, PBDT-T6-TTF and PBDT-T12-TTF showed respective power conversion efficiencies （PCEs） of 2.86% and 1.67%. When 1,8-diiodooctane （DIO） was used as the solvent additive, the PCE of PBDT-T6-TTF was remarkably elevated to 4.85%, but the use of DIO for the PBDT-T12-TTF-blend film resulted in a lower PCE of 0.91%. Atomic force microscopy （AFM） indicated that the superior efficiency of PBDT-T6-TTF with 3% DIO （v/v） should be related to the better continuous phase separation of the blend film. Nevertheless, the morphology of the PBDT-T12-TTF deteriorated when the 3% DIO （v/v） was added. Our results suggest that the alkyl-chain length on the 2D BDT units play an important role in determining the optoelectronic properties of dual 2D BDT-TT-based polymers.
基金supported by the Ministry of Science and Technology(2014CB643501)the National Natural Science Foundation of China(21520102006,21490573,51361165301)the Guangdong Natural Science Foundation(S2012030006232)
文摘A series of novel acceptor-pended conjugated polymers featuring a newly developed carbazole-derived unit are designed and synthesized. The relationships between chemical structure and optoelectronic properties of the polymers are systematically in-vestigated. The control of UV-Vis absorption spectra and energy levels in resulting polymers are achieved by introducing suitable pended acceptor units. The photovoltaic properties of the resulting polymers are evaluated by blending the polymers with （6,6）-phenyl-CTFbutyric acid methyl ester. The resulting solar cells exhibit moderate performances with high open-circuit voltage. Charge transport properties and morphology were investigated to understand the performance of corresponding solar cells.
基金This work is supported by the National Natural Science Foundation of China （Nos. U1401244, 21225418, 51521002, and 91633301）, the National Basic Research Program of China （973 program, No. 2014CB643505）, and GDUPS （2013）.
文摘In this work, a new A-D-A type nonfuUerene small molecular acceptor SilDT-IC, with a fused-ring silaindacenodithiophene （SilDT） as D unit and 2-（3-oxo-2,3-dihydroinden-l-ylidene）malononitrile （INCN） as the end A unit, was design and synthesized. The SilDT-IC film shows absorption peak and edge at 695 and 733 nm, respectively. The HOMO and LUMO of SilDT-IC are of -5.47 and -3.78 eV, respectively. Compared with carbon-bridging, the Si-bridging can result in an upper-lying LUMO level of an acceptor, which is benefit to achieve a higher open-circuit voltage in polymer solar cells （PSCs）. Complementary absorption and suitable energy level alignment between SilDT-IC and wide bandgap polymer donor PBDB-T were found. For the PBDB-T：SilDT-IC based inverted PSCs, a D/A ratio of 1 ： 1 was optimal to achieve a power conversion efficiency （PCE） of 7.27%. With thermal annealing （TA） of the blend film, a higher PCE of 8.16% could be realized due to increasing of both short-circuit current density and fill factor. After the TA treatment, hole and electron mobilities were elevated to 3.42 × 10-4 and 1.02 × 10-4 cm2·V-1.s-1, respectively. The results suggest that the SilDT, a Si-bridged fused ring, is a valuable D unit to construct efficient nonfullerene acceptors for PSCs.
