Perovskite solar cells are seen as strong competitors to silicon,but defects in solution-processed films limit both efficiency and stability.A team led by Dr.MENG Lei and Dr.LI Yongfang at the Institute of Chemistry o...Perovskite solar cells are seen as strong competitors to silicon,but defects in solution-processed films limit both efficiency and stability.A team led by Dr.MENG Lei and Dr.LI Yongfang at the Institute of Chemistry of the Chinese Academy of Sciences(ICCAS),has now shown how a simple solvent additive can overcome these obstacles.展开更多
The manipulation of the morphology of the active layers is crucial for improving the performance of organic photovoltaic(OPV)devices. In particular, the development of non-fullerene acceptors(NFAs) has led to a large ...The manipulation of the morphology of the active layers is crucial for improving the performance of organic photovoltaic(OPV)devices. In particular, the development of non-fullerene acceptors(NFAs) has led to a large number of new materials with more complex interactions. Therefore, the investigation on the morphology control mechanism is the key aspect in providing guidance for material design and device optimization. In this study, the film morphology optimization using 1,8-diiodooctane(DIO) additive and a ternary fullerene acceptor strategy have been carried out based on the PCE10:ITIC blends. It is seen that suitable amount of DIO helps to increase the crystallization of the blended thin film. However, excessive DIO elevates the crystallization-induced phase separation and the domain size can exceed the exciton diffusion length, leading to efficiency drop. The addition of fullerene acceptor can improve the carrier transport of the blends, and its presence could retard the excessive phase separation induced by DIO additive. Under the joint optimization of the solvent additive and PCBM acceptor,the film morphology achieves a balance between crystallization and phase separation scales, the exciton diffusion and carrier transport are also optimized, and the short-circuit current(JSC) and fill factor(FF) of the device can be improved significantly.展开更多
Density functional theory(DFT)calculations are employed to disclose the detailed reaction mechanism of the synthesis of 3-phenyl-2,5-dihydro-lH-benzo[d]imidazo[5,1-b][1,3]oxazine-l-thione under unassisted,water-assist...Density functional theory(DFT)calculations are employed to disclose the detailed reaction mechanism of the synthesis of 3-phenyl-2,5-dihydro-lH-benzo[d]imidazo[5,1-b][1,3]oxazine-l-thione under unassisted,water-assisted,and trifluoroacetic acid(TFA)assisted conditions by 2,2-dihydroxy-1-phenylethanone(1),(2-aminophenyl)methanol(2),and KSCN(3).The computational results show that the title mechanism can be altered and accelerated by TFA,water,and substrate 2.Three types of mechanisms are reported by DFT calculations differing in the reaction sequence of substrates,such as M1:1+2 then 3;M2:1+3 then 2;M3:2+3 then 1.It is found that the nucleophilicity of substrate 2 is stronger than 3.The DFT calculations suggest that the TFA-water co-assisted pathway of M1 is the most favorable case,which proceeds the nucleophilic addition and H-shift,intramolecular cyclization and water elimination,second nucleophilic addition and H-shift,intramolecular cyclization[3+2]cyclo-addition,and C-C bond formation and water elimination.The rate-determining step is the process of[3+2]cycloaddition.More importantly,we found that TFA and water molecules play critical roles in the whole reaction,by acting as efficient catalysts,proton shuttle,and stabilizer to stabilize the structures of transition states and intermediates via O…H-N,O…H-O,and O…H-C interactions.And they also act as hydrogen bonds(HBs)donor and acceptor to improve the reactive activity of the substrates by changing the reaction form of glyoxal monohydrates and KSCN.Substrate 2 as HBs acceptor promotes the enol-ketone tautomerization and favors the proton transfer process.The origin of the different reactivity of M1,M2,and M3 is ascribed to the pivotal non-covalent interactions that exist between catalyst(water and TFA)and reactants.Interestingly,our computations revealed that the title reaction can be performed in water instead of CH_(3)CN,which paves the way to design a greener synthetic strategy for oxazine N-fused imidazole-2-thiones and their derivatives.展开更多
Effects of thermal annealing on the optical, electrical and structural properties of 3 vol% 1,8-diiodoctane added P3HT：PC61BM active layers are investigated, concerning the performance of the bulk heterojunction poly...Effects of thermal annealing on the optical, electrical and structural properties of 3 vol% 1,8-diiodoctane added P3HT：PC61BM active layers are investigated, concerning the performance of the bulk heterojunction polymer so- lar cells by changing the heat temperature. The structure information of the active layer is analyzed by using the grazing incidence wide angle scattering diffraction combined with the optical microscope, light absorption, pho- toluminescence and the external quantum efficiency spectra. The relationship between the detail of morphology and the optical, electrical properties is investigated.展开更多
The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and ...The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and an understanding of how solvent additives affect OSCs is currently limited.In this study,we developed an in situ grazing incidence wide-angle X-ray scattering(GIWAXS)technique in the SAXS beamline(BL16 B1)at the Shanghai Synchrotron Radiation Facility,and the additive effects of1,8-diiodoctane(DIO)on the performance and morphology evolution of the PTB7-Th/PC71 BM device was investigated in depth.The results revealed that the crystal size increased with the volume ratio of DIO,and a drastic evolution of lattice space and crystal coherence length was observed during thermal annealing for the first time,to our knowledge.The discrete PC71BM molecules dissolved by DIO have an effect similar to that of the nucleating agent for PTB7-Th,boosting the crystallization of PTB7-Th,reducing phase separation,and inducing more drastic morphological evolution during thermal annealing.Our results provide a deep perspective for the mechanism of solvent additives,while also showing the significance and feasibility of the in situ GIWAXS technique we developed at BL16 B1.展开更多
Polymeric acceptors are prone to over-ag-gregate in photovoltaic thin films due to the entanglement of their long macromolecular chains,which hampers the exciton dissociation during the power conversion process.Althou...Polymeric acceptors are prone to over-ag-gregate in photovoltaic thin films due to the entanglement of their long macromolecular chains,which hampers the exciton dissociation during the power conversion process.Although high boiling point solvent can retard the over-aggregation of polymeric acceptors,the structural order is often suppressed which will limit the charge transport in all-polymer solar cells(all-PSCs).In this work,the solvent additive 1-CN and solid additive INMB-F are combined to overcome the above issue,realizing enhanced structural order with refined phase se-paration in a cutting-edge PM6:PY-IT all-PSC,with a re-markable power conversion efficiency of 19.1%,which is one of the highest efficiency reported for binary PY-IT based all-PSCs.Molecular dynamics simulations and X-ray diffraction indicate that 1-CN can facilitate the disentanglement of PY-IT chains,while INMB-F can interact with these disentangled chains to promote ordered molecular stacking,thereby en-hancing exciton dissociation and charge transport simulta-neously.展开更多
Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while ...Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while their trace residues may reduce device stability.Herein,an effective strategy of“solidification of solvent additive(SSA)”has been developed to convert additive from liquid to solid,by introducing a covalent bond into low-cost solvent diphenyl sulfide(DPS)to synthesize solid dibenzothiophene(DBT)in one-step,which achieves optimized morphology thus promoting efficiency and device stability.Owing to the fine planarity and volatilization of DBT,the DBT-processed films achieve ordered molecular crystallinity and suitable phase separation compared to the additive-free or DPS-treated ones.Importantly,the DBT-processed device also possesses improved light absorption,enhanced charge transport,and thus a champion efficiency of 17.9%is achieved in the PM6:Y6-based PSCs with an excellent additive component tolerance,reproducibility,and stability.Additionally,the DBT-processed PM6:L8-BO-based PSCs are further fabricated to study the universality of SSA strategy,offering an impressive efficiency approaching19%as one of the highest values in binary PSCs.In conclusion,this article developed a promising strategy named SSA to boost efficiency and improve stability of PSCs.展开更多
All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)have attracted more attentions due to the excellent environmental stability,however,the wide bandgap and relatively poor crystallinity of CsPbBr_(3)have been the mai...All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)have attracted more attentions due to the excellent environmental stability,however,the wide bandgap and relatively poor crystallinity of CsPbBr_(3)have been the main obstacle to improve their power conversion efficiency(PCE).Herein,we proposed an efficient and simple strategy of precursor additive in the two-step aqueous-solution method,the resulted CsPbBr_(3)film has achieved more uniform grain size,almost pure perovskite phase,smoother surface,less defects,enhanced light absorption and longer carrier lifetime.This is due to the rapid evaporation of additive(IPA and CH_(3)OH)in the CsBr/H_(2)O precursor leads to a relatively higher local CsBr concentration on the surface of PbBr_(2),which can provide more nucleation sites and accelerate the crystallization of perovskite.Further,when utilizing the optimal additive of 5%(in volume)IPA,the HTM-free carbonbased CsPbBr_(3)PSCs obtained a PCE improvement from 9.09%to 10.29%,and an ultrahigh fill factor(FF)of 85.21%.What is more,by adding 0.1 mol/L PbCl_(2)into the PbBr_(2)solution in the first step,the open circuit voltage of device has increased from 1.36 V to 1.48 V,the champion PCE reached 10.37%(steady output PCE of 10.17%),and the non-encapsulated device could maintain 85%of its initial efficiency after 50 d in the air.This work provides a cost-effective approach to grow CsPbBr_(3)film and boosts the efficiency benchmark of the CsPbBr_(3)PSCs to more than 10%,it is desirable that the highly efficient and stable CsPbBr_(3)PSCs can be developed in future.展开更多
The low band gap polymer based on benzodithiophene(BDT)-thieno[3,4-b]thiophene(TT)backbone,PBDT-TS1,was synthesized following our previous work and the bulk heterojunction(BHJ)material comprising PBDT-TS1/PC71BM was o...The low band gap polymer based on benzodithiophene(BDT)-thieno[3,4-b]thiophene(TT)backbone,PBDT-TS1,was synthesized following our previous work and the bulk heterojunction(BHJ)material comprising PBDT-TS1/PC71BM was optimized and characterized.By processing the active layer with different additives i.e.1,8-diiodooctane(DIO),1-chloronaphthalene(CN)and 1,8-octanedithiol(ODT)and optimizing the ratio of each additive in the host solvent,a high PCE of 9.98%was obtained under the condition of utilizing 3%DIO as processing additive in CB.The effect of varied additives on photovoltaic performance was illustrated with atomic force microscopy(AFM)and transmission electron microscope(TEM)measurements that explained changes in photovoltaic parameters.These results provide valuable information of solvent additive choice in device optimization of PBDTTT polymers,and the systematic device optimization could be applied in other efficient photovoltaic polymers.Apparently,this work presents a great advance in single junction PSCs,especially in PSCs with conventional architecture.展开更多
Photovoltaic performance of the organic solar cells （OSCs） based on 2-（（5＇-（4-（（4-（（E）-2-（5＇-（2,2-dicyanovinyl）-3＇,4-dihexyl- 2,2＇-bithiophen-5-yl）vinyl） phenyl）（phenyl）amino）styryl）-4~4＇-dihe...Photovoltaic performance of the organic solar cells （OSCs） based on 2-（（5＇-（4-（（4-（（E）-2-（5＇-（2,2-dicyanovinyl）-3＇,4-dihexyl- 2,2＇-bithiophen-5-yl）vinyl） phenyl）（phenyl）amino）styryl）-4~4＇-dihexyl-2,2＇-bithiophen-5-yl）methylene）malononitrile （L（TPA- bTV-DCN）） as donor and PC70BM as acceptor was optimized using 0.25 vol% high boiling point solvent additive of 1-chloronaphthalene （CN）, 1,6-hexanedithiol （HDT）, or 1,8-diodooctane （DIO）. The optimized OSC based on L（TPA-bTV- DCN）-PC70BM （1：2, w/w） with 0.25 vol% CN exhibits an enhanced power conversion efficiency （PCE） of 2.61%, with Voc of 0.87 V, Jsc of 6.95 mA/cm2, and FF of 43.2%, under the illumination of 100 mW/cm2 AM 1.5 G simulated solar light, whereas the PCE of the OSC based on the same active layer without additive is only 1.79%. The effect of the additive on absorption spectra and the atomic force microscopy images of L（TPA-bTV-DCN）-PCv0BM blend films were further investigated. The improved efficiency of the device could be ascribed to the enhanced absorption and optimized domain size in the L（TPA-bTV-DCN）-PC70BM blend film.展开更多
Organic solar cells(OSCs)have unique advantages of light weight,low-cost solution processing,and capability to be fabricated into flexible and semitransparent devices,which are widely recognized as a promising photovo...Organic solar cells(OSCs)have unique advantages of light weight,low-cost solution processing,and capability to be fabricated into flexible and semitransparent devices,which are widely recognized as a promising photovoltaic technology.Photoactive layers of the OSCs are composed of a blend of a p-type organic semiconductor as a donor(D)and an n-type organic semiconductor as acceptor(A).The morphology of the active layer with D/A nano-scaled aggregation and face-onπconjugated packing,and D/A interpenetrating network is crucial for achieving high photovoltaic performance of the OSCs.Therefore,great efforts have been devoted to control and optimize morphology of the active layers.This perspective focuses on the morphological control by solvent/solid processing additives and the morphology optimization by postdeposition treatment with thermal annealing and/or solvent vapor annealing,which have been extensively adopted and exhibit promising positive effect in optimizing the morphology.Representative examples are given and discussed to understand the foundation of the postdeposition treatments on tuning the morphology.Insights into the role of the postdeposition treatments and additive treatments on the morphology optimization will be beneficial to further improvement in morphology optimization for practical organic photovoltaic application.展开更多
Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries(LMBs).However,the implementation of traditional carbonate electrolyte is greatly hindered by the generat...Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries(LMBs).However,the implementation of traditional carbonate electrolyte is greatly hindered by the generation of an unstable electrode interphase and corrosive by-product(HF).Herein,we propose a triple-function eutectic solvent additive of N-methylacetamide(NmAc)with LiNO_(3) to enhance the stability and compatibility of carbonate electrolyte.Firstly,the addition of NmAc significantly improves the solubility of LiNO_(3) in carbonate electrolyte by forming an eutectic pair,which regulates the Li~+solvation structure and leads to dense and homogenous Li plating.Secondly,the hydrolysis of acidic PF_5 is effectively alleviated due to the strong complexation of NmAc with PF_5,thus reducing the generation of corrosive HF.In addition,the optimized cathode electrolyte interphase layer decreases the structural degradation and transition metal dissolution.Consequently,Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cells with the designed electrolyte deliver superior long-term cycle reversibility and excellent rate capability.This study unveils the rationale for incorporating eutectic solvent additives within carbonate electrolytes,which significantly contribute to the advancement of their practical application for high-voltage LMBs.展开更多
Introducing ethynylene linkages in a conjugated molecule can deepen the HOMO level, decrease the steric con- straints and better delocalize the n electrons and so on, which are beneficial for organic solar cells. Furt...Introducing ethynylene linkages in a conjugated molecule can deepen the HOMO level, decrease the steric con- straints and better delocalize the n electrons and so on, which are beneficial for organic solar cells. Furthermore, the typical method of introducing acetylene linkages by Sonogashira reactions can avoid the usage of toxic stannyl in- termediates and potentially dangerous lithiation reactions. In this study, two simple small molecules BEDPP and NEDPP are designed and synthesized, in which two diketopyrrolopyrrole units are symmetrically connected to benzene and naphthalene cores, respectively, via acetylene linkages. And the BHJ （Bulk Heterojunction） solar cells based on BEDPP and NEDPP without using solvent additive and without any post-treatment for the active layers provide us power conversion efficieneies of 1.48% and 2.31% with remarkably high open circuit voltages up to 0.90 and 0.98 V, respectively.展开更多
Organic solar cells(OSCs)have demonstrated over 19%power conversion efficiency(PCE)with the help of material innovation and device optimization.Co-working with newly designed materials,traditional solvent additives,1-...Organic solar cells(OSCs)have demonstrated over 19%power conversion efficiency(PCE)with the help of material innovation and device optimization.Co-working with newly designed materials,traditional solvent additives,1-chloronaphthalene(CN),and 1,8-diodooctane(DIO)are still powerful in morphology modulation towards satisfying efficiencies.Here,we chose recently reported high-performance polymer donors(PM6&D18-Fu)and small molecular acceptors(Y6&L8-BO)as active layer materials and processed them by different conditions(CN or DIO or none).Based on corresponding 12 groups of device results,and their film morphology characterizations(both ex-situ and in-situ ones),the property-performance relationships are revealed case by case.It is thereby supposed to be taken as a successful attempt to demonstrate the importance and complexity of donor-acceptoradditive interaction,since the device performance and physics analyses are also tightly combined with morphology variation.Furthermore,ternary blend construction for PCE improvement provides an approaching 19%level and showcases the potential of understanding-guided-optimization(UGO)in the future of OSCs.展开更多
文摘Perovskite solar cells are seen as strong competitors to silicon,but defects in solution-processed films limit both efficiency and stability.A team led by Dr.MENG Lei and Dr.LI Yongfang at the Institute of Chemistry of the Chinese Academy of Sciences(ICCAS),has now shown how a simple solvent additive can overcome these obstacles.
基金financially supported by the National Natural Science Foundation of China (Nos.51973110,21734009,21905102 and 22109094)the National Key R&D Program of China (Nos.2020YFB1505500 and 2020YFB1505502)+3 种基金the Program of Shanghai Science and Technology Commission science and technology innovation action plan (Nos.20ZR1426200,20511103800,20511103802 and 20511103803)the Natural Science Foundation of Shandong Province (No.ZR2019LFG005)the Key research project of Shandong Province (No.2020CXGC010403)the Center of Hydrogen Science,Shanghai Jiao Tong University,China。
文摘The manipulation of the morphology of the active layers is crucial for improving the performance of organic photovoltaic(OPV)devices. In particular, the development of non-fullerene acceptors(NFAs) has led to a large number of new materials with more complex interactions. Therefore, the investigation on the morphology control mechanism is the key aspect in providing guidance for material design and device optimization. In this study, the film morphology optimization using 1,8-diiodooctane(DIO) additive and a ternary fullerene acceptor strategy have been carried out based on the PCE10:ITIC blends. It is seen that suitable amount of DIO helps to increase the crystallization of the blended thin film. However, excessive DIO elevates the crystallization-induced phase separation and the domain size can exceed the exciton diffusion length, leading to efficiency drop. The addition of fullerene acceptor can improve the carrier transport of the blends, and its presence could retard the excessive phase separation induced by DIO additive. Under the joint optimization of the solvent additive and PCBM acceptor,the film morphology achieves a balance between crystallization and phase separation scales, the exciton diffusion and carrier transport are also optimized, and the short-circuit current(JSC) and fill factor(FF) of the device can be improved significantly.
基金Financial support by the National Natural Science Foundation of China(21873018,21573036,and 21603028)the Fundamental Research Funds for the Central Universities(2412019FZ010)the open project of the Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis(130028655)are greatly acknowledged
文摘Density functional theory(DFT)calculations are employed to disclose the detailed reaction mechanism of the synthesis of 3-phenyl-2,5-dihydro-lH-benzo[d]imidazo[5,1-b][1,3]oxazine-l-thione under unassisted,water-assisted,and trifluoroacetic acid(TFA)assisted conditions by 2,2-dihydroxy-1-phenylethanone(1),(2-aminophenyl)methanol(2),and KSCN(3).The computational results show that the title mechanism can be altered and accelerated by TFA,water,and substrate 2.Three types of mechanisms are reported by DFT calculations differing in the reaction sequence of substrates,such as M1:1+2 then 3;M2:1+3 then 2;M3:2+3 then 1.It is found that the nucleophilicity of substrate 2 is stronger than 3.The DFT calculations suggest that the TFA-water co-assisted pathway of M1 is the most favorable case,which proceeds the nucleophilic addition and H-shift,intramolecular cyclization and water elimination,second nucleophilic addition and H-shift,intramolecular cyclization[3+2]cyclo-addition,and C-C bond formation and water elimination.The rate-determining step is the process of[3+2]cycloaddition.More importantly,we found that TFA and water molecules play critical roles in the whole reaction,by acting as efficient catalysts,proton shuttle,and stabilizer to stabilize the structures of transition states and intermediates via O…H-N,O…H-O,and O…H-C interactions.And they also act as hydrogen bonds(HBs)donor and acceptor to improve the reactive activity of the substrates by changing the reaction form of glyoxal monohydrates and KSCN.Substrate 2 as HBs acceptor promotes the enol-ketone tautomerization and favors the proton transfer process.The origin of the different reactivity of M1,M2,and M3 is ascribed to the pivotal non-covalent interactions that exist between catalyst(water and TFA)and reactants.Interestingly,our computations revealed that the title reaction can be performed in water instead of CH_(3)CN,which paves the way to design a greener synthetic strategy for oxazine N-fused imidazole-2-thiones and their derivatives.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51272022 and 11474018the Research Fund for the Doctoral Program of Higher Education of China under Grant No 20120009130005the Fundamental Research Funds for the Central Universities under Grant No 2012JBZ001
文摘Effects of thermal annealing on the optical, electrical and structural properties of 3 vol% 1,8-diiodoctane added P3HT：PC61BM active layers are investigated, concerning the performance of the bulk heterojunction polymer so- lar cells by changing the heat temperature. The structure information of the active layer is analyzed by using the grazing incidence wide angle scattering diffraction combined with the optical microscope, light absorption, pho- toluminescence and the external quantum efficiency spectra. The relationship between the detail of morphology and the optical, electrical properties is investigated.
基金supported by the National Natural Science Foundation of China(Nos.U1932118,2005324)the National Key R&D Program of China(Nos.2017YFA0403002,2018YFB0704201)。
文摘The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and an understanding of how solvent additives affect OSCs is currently limited.In this study,we developed an in situ grazing incidence wide-angle X-ray scattering(GIWAXS)technique in the SAXS beamline(BL16 B1)at the Shanghai Synchrotron Radiation Facility,and the additive effects of1,8-diiodoctane(DIO)on the performance and morphology evolution of the PTB7-Th/PC71 BM device was investigated in depth.The results revealed that the crystal size increased with the volume ratio of DIO,and a drastic evolution of lattice space and crystal coherence length was observed during thermal annealing for the first time,to our knowledge.The discrete PC71BM molecules dissolved by DIO have an effect similar to that of the nucleating agent for PTB7-Th,boosting the crystallization of PTB7-Th,reducing phase separation,and inducing more drastic morphological evolution during thermal annealing.Our results provide a deep perspective for the mechanism of solvent additives,while also showing the significance and feasibility of the in situ GIWAXS technique we developed at BL16 B1.
基金supported by the National Natural Science Foundation of China (52273196, 52073221 and 52203238)。
文摘Polymeric acceptors are prone to over-ag-gregate in photovoltaic thin films due to the entanglement of their long macromolecular chains,which hampers the exciton dissociation during the power conversion process.Although high boiling point solvent can retard the over-aggregation of polymeric acceptors,the structural order is often suppressed which will limit the charge transport in all-polymer solar cells(all-PSCs).In this work,the solvent additive 1-CN and solid additive INMB-F are combined to overcome the above issue,realizing enhanced structural order with refined phase se-paration in a cutting-edge PM6:PY-IT all-PSC,with a re-markable power conversion efficiency of 19.1%,which is one of the highest efficiency reported for binary PY-IT based all-PSCs.Molecular dynamics simulations and X-ray diffraction indicate that 1-CN can facilitate the disentanglement of PY-IT chains,while INMB-F can interact with these disentangled chains to promote ordered molecular stacking,thereby en-hancing exciton dissociation and charge transport simulta-neously.
基金the financial support from the Scientific Research Project of Education Department of Hunan Province(21C0091)the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology)(2023skllmd-13)+6 种基金the support from the National Natural Science Foundation of China(22209131,22005121)the open fund support from School of Materials Science and Engineering,Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications(GDRGCS2021002,GDRGCS2022003,GDRGCS2022002)the support from the National Key Research and Development Program of China(2022YFE0132400)the National Natural Science Foundation of China(21875182,52173023)the Key Scientific and Technological Innovation Team Project of Shaanxi Province(2020TD-002)111 Project 2.0(BP0618008)supported by the Director,Office of Science,Office of Basic Energy Sciences,of the U.S.Department of Energy(DE-AC0205CH11231)。
文摘Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while their trace residues may reduce device stability.Herein,an effective strategy of“solidification of solvent additive(SSA)”has been developed to convert additive from liquid to solid,by introducing a covalent bond into low-cost solvent diphenyl sulfide(DPS)to synthesize solid dibenzothiophene(DBT)in one-step,which achieves optimized morphology thus promoting efficiency and device stability.Owing to the fine planarity and volatilization of DBT,the DBT-processed films achieve ordered molecular crystallinity and suitable phase separation compared to the additive-free or DPS-treated ones.Importantly,the DBT-processed device also possesses improved light absorption,enhanced charge transport,and thus a champion efficiency of 17.9%is achieved in the PM6:Y6-based PSCs with an excellent additive component tolerance,reproducibility,and stability.Additionally,the DBT-processed PM6:L8-BO-based PSCs are further fabricated to study the universality of SSA strategy,offering an impressive efficiency approaching19%as one of the highest values in binary PSCs.In conclusion,this article developed a promising strategy named SSA to boost efficiency and improve stability of PSCs.
基金the National Natural Science Foundation of China under Grants 62004151,62274126 and 62204189the Special Financial Grant from the China Postdoctoral Science Foundation under Grant 2020T130490+1 种基金Young Talent Fund of Association for Science and Technology in Shaanxi under Grant 20220115Fundamental Research Funds for the National 111 Center.
文摘All-inorganic CsPbBr_(3)perovskite solar cells(PSCs)have attracted more attentions due to the excellent environmental stability,however,the wide bandgap and relatively poor crystallinity of CsPbBr_(3)have been the main obstacle to improve their power conversion efficiency(PCE).Herein,we proposed an efficient and simple strategy of precursor additive in the two-step aqueous-solution method,the resulted CsPbBr_(3)film has achieved more uniform grain size,almost pure perovskite phase,smoother surface,less defects,enhanced light absorption and longer carrier lifetime.This is due to the rapid evaporation of additive(IPA and CH_(3)OH)in the CsBr/H_(2)O precursor leads to a relatively higher local CsBr concentration on the surface of PbBr_(2),which can provide more nucleation sites and accelerate the crystallization of perovskite.Further,when utilizing the optimal additive of 5%(in volume)IPA,the HTM-free carbonbased CsPbBr_(3)PSCs obtained a PCE improvement from 9.09%to 10.29%,and an ultrahigh fill factor(FF)of 85.21%.What is more,by adding 0.1 mol/L PbCl_(2)into the PbBr_(2)solution in the first step,the open circuit voltage of device has increased from 1.36 V to 1.48 V,the champion PCE reached 10.37%(steady output PCE of 10.17%),and the non-encapsulated device could maintain 85%of its initial efficiency after 50 d in the air.This work provides a cost-effective approach to grow CsPbBr_(3)film and boosts the efficiency benchmark of the CsPbBr_(3)PSCs to more than 10%,it is desirable that the highly efficient and stable CsPbBr_(3)PSCs can be developed in future.
基金supported by the National Basic Research Program of China(2014CB643501)the National Natural Science Foundation of China(21325419,51373181,91333204)+1 种基金the Chinese Academy of Sciences(XDB12030200,KJZD-EW-J01)the Science and Technology Commission of Beijing(Z131100006013002)
文摘The low band gap polymer based on benzodithiophene(BDT)-thieno[3,4-b]thiophene(TT)backbone,PBDT-TS1,was synthesized following our previous work and the bulk heterojunction(BHJ)material comprising PBDT-TS1/PC71BM was optimized and characterized.By processing the active layer with different additives i.e.1,8-diiodooctane(DIO),1-chloronaphthalene(CN)and 1,8-octanedithiol(ODT)and optimizing the ratio of each additive in the host solvent,a high PCE of 9.98%was obtained under the condition of utilizing 3%DIO as processing additive in CB.The effect of varied additives on photovoltaic performance was illustrated with atomic force microscopy(AFM)and transmission electron microscope(TEM)measurements that explained changes in photovoltaic parameters.These results provide valuable information of solvent additive choice in device optimization of PBDTTT polymers,and the systematic device optimization could be applied in other efficient photovoltaic polymers.Apparently,this work presents a great advance in single junction PSCs,especially in PSCs with conventional architecture.
基金supported by the National Basic Research Program of China(2014CB643501)the National Natural Science Foundation of China(91333204)the support from Ministry of Education and Jiangsu Province(20100092120037,XNY-48-037)
文摘Photovoltaic performance of the organic solar cells （OSCs） based on 2-（（5＇-（4-（（4-（（E）-2-（5＇-（2,2-dicyanovinyl）-3＇,4-dihexyl- 2,2＇-bithiophen-5-yl）vinyl） phenyl）（phenyl）amino）styryl）-4~4＇-dihexyl-2,2＇-bithiophen-5-yl）methylene）malononitrile （L（TPA- bTV-DCN）） as donor and PC70BM as acceptor was optimized using 0.25 vol% high boiling point solvent additive of 1-chloronaphthalene （CN）, 1,6-hexanedithiol （HDT）, or 1,8-diodooctane （DIO）. The optimized OSC based on L（TPA-bTV- DCN）-PC70BM （1：2, w/w） with 0.25 vol% CN exhibits an enhanced power conversion efficiency （PCE） of 2.61%, with Voc of 0.87 V, Jsc of 6.95 mA/cm2, and FF of 43.2%, under the illumination of 100 mW/cm2 AM 1.5 G simulated solar light, whereas the PCE of the OSC based on the same active layer without additive is only 1.79%. The effect of the additive on absorption spectra and the atomic force microscopy images of L（TPA-bTV-DCN）-PCv0BM blend films were further investigated. The improved efficiency of the device could be ascribed to the enhanced absorption and optimized domain size in the L（TPA-bTV-DCN）-PC70BM blend film.
基金National Natural Science Foundation of China,Grant/Award Numbers:22022509,51873140,51820105003。
文摘Organic solar cells(OSCs)have unique advantages of light weight,low-cost solution processing,and capability to be fabricated into flexible and semitransparent devices,which are widely recognized as a promising photovoltaic technology.Photoactive layers of the OSCs are composed of a blend of a p-type organic semiconductor as a donor(D)and an n-type organic semiconductor as acceptor(A).The morphology of the active layer with D/A nano-scaled aggregation and face-onπconjugated packing,and D/A interpenetrating network is crucial for achieving high photovoltaic performance of the OSCs.Therefore,great efforts have been devoted to control and optimize morphology of the active layers.This perspective focuses on the morphological control by solvent/solid processing additives and the morphology optimization by postdeposition treatment with thermal annealing and/or solvent vapor annealing,which have been extensively adopted and exhibit promising positive effect in optimizing the morphology.Representative examples are given and discussed to understand the foundation of the postdeposition treatments on tuning the morphology.Insights into the role of the postdeposition treatments and additive treatments on the morphology optimization will be beneficial to further improvement in morphology optimization for practical organic photovoltaic application.
基金supported by the National Natural Science Foundation of China(22379166)Natural Science Foundation for Distinguished Young Scholars of Hunan Province(2022JJ10089)+1 种基金Central South University Innovation-Driven Research Program(2023CXQD034)supported in part by the High-Performance Computing Center of Central South University。
文摘Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries(LMBs).However,the implementation of traditional carbonate electrolyte is greatly hindered by the generation of an unstable electrode interphase and corrosive by-product(HF).Herein,we propose a triple-function eutectic solvent additive of N-methylacetamide(NmAc)with LiNO_(3) to enhance the stability and compatibility of carbonate electrolyte.Firstly,the addition of NmAc significantly improves the solubility of LiNO_(3) in carbonate electrolyte by forming an eutectic pair,which regulates the Li~+solvation structure and leads to dense and homogenous Li plating.Secondly,the hydrolysis of acidic PF_5 is effectively alleviated due to the strong complexation of NmAc with PF_5,thus reducing the generation of corrosive HF.In addition,the optimized cathode electrolyte interphase layer decreases the structural degradation and transition metal dissolution.Consequently,Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cells with the designed electrolyte deliver superior long-term cycle reversibility and excellent rate capability.This study unveils the rationale for incorporating eutectic solvent additives within carbonate electrolytes,which significantly contribute to the advancement of their practical application for high-voltage LMBs.
文摘Introducing ethynylene linkages in a conjugated molecule can deepen the HOMO level, decrease the steric con- straints and better delocalize the n electrons and so on, which are beneficial for organic solar cells. Furthermore, the typical method of introducing acetylene linkages by Sonogashira reactions can avoid the usage of toxic stannyl in- termediates and potentially dangerous lithiation reactions. In this study, two simple small molecules BEDPP and NEDPP are designed and synthesized, in which two diketopyrrolopyrrole units are symmetrically connected to benzene and naphthalene cores, respectively, via acetylene linkages. And the BHJ （Bulk Heterojunction） solar cells based on BEDPP and NEDPP without using solvent additive and without any post-treatment for the active layers provide us power conversion efficieneies of 1.48% and 2.31% with remarkably high open circuit voltages up to 0.90 and 0.98 V, respectively.
基金Research Grants Council of Hong Kong,Grant/Award Numbers:15221320,C5037-18GRGC Senior Research Fellowship Scheme,Grant/Award Number:SRFS2223-5S01+5 种基金Shenzhen Science and Technology Innovation Commission,Grant/Award Number:JCYJ20200109105003940Hong Kong Polytechnic University Internal Research Funds:Sir Sze-yuen Chung Endowed Professorship Fund,Grant/Award Number:8-8480RISE(Q-CDBK),Grant/Award Numbers:G-SAC5,1-YW4CGuangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices,Grant/Award Number:2019B121205001Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2022A1515010875,2021A1515110017Natural Science Foundation of Top Talent of SZTU。
文摘Organic solar cells(OSCs)have demonstrated over 19%power conversion efficiency(PCE)with the help of material innovation and device optimization.Co-working with newly designed materials,traditional solvent additives,1-chloronaphthalene(CN),and 1,8-diodooctane(DIO)are still powerful in morphology modulation towards satisfying efficiencies.Here,we chose recently reported high-performance polymer donors(PM6&D18-Fu)and small molecular acceptors(Y6&L8-BO)as active layer materials and processed them by different conditions(CN or DIO or none).Based on corresponding 12 groups of device results,and their film morphology characterizations(both ex-situ and in-situ ones),the property-performance relationships are revealed case by case.It is thereby supposed to be taken as a successful attempt to demonstrate the importance and complexity of donor-acceptoradditive interaction,since the device performance and physics analyses are also tightly combined with morphology variation.Furthermore,ternary blend construction for PCE improvement provides an approaching 19%level and showcases the potential of understanding-guided-optimization(UGO)in the future of OSCs.
