Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced ...Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced into perovskites.The experiments and calculations reveal that betulin can effectively passivate the uncoordinated lead ions in perovskites via sharing the lone pair electrons of hydroxyl group,promoting charge transport.As a result,the power conversion efficiencies of the p-i-n planar PSCs remarkably increase from 19.14%to 21.15%,with the improvement of other parameters.The hydrogen bonds of betulin lock methylamine and halogen ions along the grain boundaries and on the film surface and thus suppress ion migration,further stabilizing perovskite crystal structures.These positive effects enable the PSCs to maintain 90%of the initial efficiency after 30 days in ambient air with 60%±5%relative humidity,75%after 300 h aging at 85℃,and 55%after 250 h light soaking,respectively.This work opens a new pathway for using nontoxic and low-cost biomaterials from forest to make highly efficient and stable PSCs.展开更多
Non-fullerene acceptor(NFA) based organic solar cells(OSCs) are of high efficiency and low energy loss and low recombination features, which is owing to the advantage of non-fullerene acceptors. The photophysics inves...Non-fullerene acceptor(NFA) based organic solar cells(OSCs) are of high efficiency and low energy loss and low recombination features, which is owing to the advantage of non-fullerene acceptors. The photophysics investigation of non-fullerene solar cells, in comparing to fullerene based analogue as well as mixed acceptor ternary blends could help to understand the working mechanism of NFA functioning mechanism. We choose PBDB-T donor, the fullerene derivative PC71 BM acceptor, and the non-fullerene acceptor ITIC as the model system, to construct binary and ternary solar cells, which then subject to ultrafast spectroscopy investigation. The charge transfer pathway in binary and ternary blends is revealed.And it is seen that ITIC leads to a faster exciton separation and exciton diffusion. ITIC in blends suppresses the geminate recombination and shows smaller amount of charge transfer states, which is beneficial for the device performance. And the addition of ITIC enhances the crystallinity for both donor and acceptor leads to a morphology change of forming bicontinuous crystalline networks and phase separation. In a consequence, fill factor and JSC, increase dramatically for the related OSC.展开更多
Organic solar cells(OSCs)have attracted huge attention because of their unique merits[1−3].In last few years,thanks to the design of new materials and device engineering,the power conversion efficiencies(PCEs)of OSCs ...Organic solar cells(OSCs)have attracted huge attention because of their unique merits[1−3].In last few years,thanks to the design of new materials and device engineering,the power conversion efficiencies(PCEs)of OSCs have surpassed 18%[4−8].The PM6:Y6 cells are efficient binary cells,offering high PCEs over 16%[9−11].The high performance originates from the efficient free charge generation and the ground state dipole field at the donor-acceptor interface that promotes the exciton dissociation[12].展开更多
We build a general multi-length-scale morphology model with mixing phase and pure phase fibril structure,and simulate corresponding organic solar cells performance.Systematical multi-length-scale morphology optimizati...We build a general multi-length-scale morphology model with mixing phase and pure phase fibril structure,and simulate corresponding organic solar cells performance.Systematical multi-length-scale morphology optimization process by changing the proportion of mixing phase and pure phase in different period width cases shows a clear correlation between period width and device performance that a smaller period width with appropriate proportion of mixing phase and fibril structure is advantageous to achieve high-performance devices.Experiments on multiple donor/acceptor blends have been carried out by varying the composition and processing condition,which afford good structure-performance correlation that supports the model prediction.It is demonstrated that building such a multi-length-scale morphology merging the synergistic effects of mixing and pure phases is indeed an imperative avenue to improve device efficiency.展开更多
In nonfullerene acceptor-(NFA-)based solar cells,the exciton splitting takes place at both domain interface and donor/acceptor mixture,which brings in the state of mixing phase into focus.The energetics and morphology...In nonfullerene acceptor-(NFA-)based solar cells,the exciton splitting takes place at both domain interface and donor/acceptor mixture,which brings in the state of mixing phase into focus.The energetics and morphology are key parameters dictating the charge generation,diffusion,and recombination.It is revealed that tailoringthe electronic properties of the mixing region by doping with larger-bandgap components could reduce the density of state but elevate the filling state level,leading to improved open-circuit voltage(V_(OC))and reduced recombination.The monomolecular and bimolecular recombinations are shown to be intercorrelated,which show a Gaussian-like relationship with V_(OC) and linear relationship with short-circuit current density(JSC)and fill factor(FF).The kinetics of hole transfer and exciton diffusion scale with JSC similarly,indicating the carrier generation in mixing region and crystalline domain are equally important.From the morphology perspective,the crystalline order could contribute to V_(OC) improvement,and the fibrillar structure strongly affects the FF.These observations highlight the importance of the mixing region and its connection with crystalline domains and point out the design rules to optimize the mixing phase structure,which is an effective approach to further improve device performance.展开更多
基金supported by the National Natural Science Foundation of China(21875067,51811530011,11604099)the Fundamental Research Funds for the Central Universities,Shanghai Rising-Star(19QA1403100)+2 种基金ECNU Multifunctional Platform for Innovation(006)the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support。
文摘Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced into perovskites.The experiments and calculations reveal that betulin can effectively passivate the uncoordinated lead ions in perovskites via sharing the lone pair electrons of hydroxyl group,promoting charge transport.As a result,the power conversion efficiencies of the p-i-n planar PSCs remarkably increase from 19.14%to 21.15%,with the improvement of other parameters.The hydrogen bonds of betulin lock methylamine and halogen ions along the grain boundaries and on the film surface and thus suppress ion migration,further stabilizing perovskite crystal structures.These positive effects enable the PSCs to maintain 90%of the initial efficiency after 30 days in ambient air with 60%±5%relative humidity,75%after 300 h aging at 85℃,and 55%after 250 h light soaking,respectively.This work opens a new pathway for using nontoxic and low-cost biomaterials from forest to make highly efficient and stable PSCs.
基金financially supported by the grant from the National Natural Science Foundation of China (Nos.21734009, 11327902, 11574204, 11774224, and 21822505)National Key Research and Development Program of China (2017YFA0207700)carried out at beam line 7.3.3 and 11.0.1.2 at the Advanced Light Source, Molecular Foundry, Lawrence Berkeley National Laboratory, which was supported by the DOE, Office of Science, and Office of Basic Energy Sciences。
文摘Non-fullerene acceptor(NFA) based organic solar cells(OSCs) are of high efficiency and low energy loss and low recombination features, which is owing to the advantage of non-fullerene acceptors. The photophysics investigation of non-fullerene solar cells, in comparing to fullerene based analogue as well as mixed acceptor ternary blends could help to understand the working mechanism of NFA functioning mechanism. We choose PBDB-T donor, the fullerene derivative PC71 BM acceptor, and the non-fullerene acceptor ITIC as the model system, to construct binary and ternary solar cells, which then subject to ultrafast spectroscopy investigation. The charge transfer pathway in binary and ternary blends is revealed.And it is seen that ITIC leads to a faster exciton separation and exciton diffusion. ITIC in blends suppresses the geminate recombination and shows smaller amount of charge transfer states, which is beneficial for the device performance. And the addition of ITIC enhances the crystallinity for both donor and acceptor leads to a morphology change of forming bicontinuous crystalline networks and phase separation. In a consequence, fill factor and JSC, increase dramatically for the related OSC.
基金supported by the National Natural Science Foundation of China(21875067,11604099,51811530011)the Fundamental Research Funds for the Central Central Universities,Shanghai Rising-Star(19QA1403100)+6 种基金East China Normal University Multifunctional Platform for Innovationthe STINT grant(CH2017-7163)the National Natural Science Foundation of China(51803060)the Science and Technology Program of Guangdong Province(2018A030313045)the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial supportthe open project of State Key Laboratory of Luminescent Materials and Devices(2021-skllmd-07).
文摘Organic solar cells(OSCs)have attracted huge attention because of their unique merits[1−3].In last few years,thanks to the design of new materials and device engineering,the power conversion efficiencies(PCEs)of OSCs have surpassed 18%[4−8].The PM6:Y6 cells are efficient binary cells,offering high PCEs over 16%[9−11].The high performance originates from the efficient free charge generation and the ground state dipole field at the donor-acceptor interface that promotes the exciton dissociation[12].
基金supported by the National Natural Science Foundation of China(51973110,21734009,22109094,21905102)the Program of Shanghai Science and Technology Commission Science and Technology Innovation Action Plan(20ZR1426200,20511103800,20511103802,20511103803)+1 种基金the Natural Science Foundation of Shandong Province,China(ZR2019LFG005)Key Research Project of Shandong Province(2020CXGC010403)。
文摘We build a general multi-length-scale morphology model with mixing phase and pure phase fibril structure,and simulate corresponding organic solar cells performance.Systematical multi-length-scale morphology optimization process by changing the proportion of mixing phase and pure phase in different period width cases shows a clear correlation between period width and device performance that a smaller period width with appropriate proportion of mixing phase and fibril structure is advantageous to achieve high-performance devices.Experiments on multiple donor/acceptor blends have been carried out by varying the composition and processing condition,which afford good structure-performance correlation that supports the model prediction.It is demonstrated that building such a multi-length-scale morphology merging the synergistic effects of mixing and pure phases is indeed an imperative avenue to improve device efficiency.
基金This work was financially supported by the grant from the National Natural Science Foundation of China(Grant Nos.51973110,21734009,and 21905102)the National Key R&D Program of China under grant nos.2020YFB1505500 and 2020YFB1505502+3 种基金the Program of Shanghai Science and Technology Commission science and technology innovation action plan(20ZR1426200,20511103800,20511103802,and 20511103803)the Natural Science Foundation of Shandong Province,China(ZR2019LFG005)the Key Research Project of Shandong Province under grant no.2020CXGC010403beamline 7.3.3 and 11.0.1.2 at the Advanced Light Source,Lawrence Berkeley National Laboratory,which was supported by the DOE,Office of Science,and Office of Basic Energy Sciences.
文摘In nonfullerene acceptor-(NFA-)based solar cells,the exciton splitting takes place at both domain interface and donor/acceptor mixture,which brings in the state of mixing phase into focus.The energetics and morphology are key parameters dictating the charge generation,diffusion,and recombination.It is revealed that tailoringthe electronic properties of the mixing region by doping with larger-bandgap components could reduce the density of state but elevate the filling state level,leading to improved open-circuit voltage(V_(OC))and reduced recombination.The monomolecular and bimolecular recombinations are shown to be intercorrelated,which show a Gaussian-like relationship with V_(OC) and linear relationship with short-circuit current density(JSC)and fill factor(FF).The kinetics of hole transfer and exciton diffusion scale with JSC similarly,indicating the carrier generation in mixing region and crystalline domain are equally important.From the morphology perspective,the crystalline order could contribute to V_(OC) improvement,and the fibrillar structure strongly affects the FF.These observations highlight the importance of the mixing region and its connection with crystalline domains and point out the design rules to optimize the mixing phase structure,which is an effective approach to further improve device performance.