Ideal nanoscale phase-separated morphology is the primary condition to obtain high photovoltaic conversion efficiency(PCE)and high stability of organic solar cells(OSCs).However,the differences in solubility,miscibili...Ideal nanoscale phase-separated morphology is the primary condition to obtain high photovoltaic conversion efficiency(PCE)and high stability of organic solar cells(OSCs).However,the differences in solubility,miscibility and crystallinity between donors and acceptors make it difficult to achieve the optimal active layer morphology of OSCs.Herein,the volatile solid additive 3,5-dibromotoluene(DTL)with strong electronegativity and dipole moment has been developed for OSCs.DTL can interact with the acceptor,modulating its crystallization and stacking,enhancing donor/acceptor miscibility,reducing trap density,inhibiting carrier recombination,and balancing charge transport.Notably,the introduction of DTL finely tunes the energy level of the accepto r,which greatly enhances the open-circuit voltage(V_(OC))of the device compared to the conventional additive 1,8-diiodooctane(DIO).As a result,the DTL-treated PM6:L8-BObased OSCs obtained a high PCE of 18.87%and enhanced stability.Furthermore,the PM6:PM1:L8-BO+DTL-based OSCs achieved a champion PCE of 19.11%.This work deepens the working mechanism of additive strategy for regulating the morphology and improving performance,providing an effective method for achieving high-performance OSCs.展开更多
Achieving high-performance perovskite solar modules(pero-SMs)over large areas under ambient conditions remains a significant barrier to the commercialization of perovskite photovoltaics.This challenge arises from the ...Achieving high-performance perovskite solar modules(pero-SMs)over large areas under ambient conditions remains a significant barrier to the commercialization of perovskite photovoltaics.This challenge arises from the strong solvent-perovskite coordination interactions in the hygroscopic perovskite precursor ink,which complicate the control of nucleation-growth kinetics and phase evolution during film formation in the presence of moisture,thereby hindering the formation of high-quality perovskite films.In this work,a“vip-solvent”additive strategy was developed by incorporating N,N-dimethylthioformamide(DMT)into the perovskite precursor ink to effectively modulate the coordination between the solvent and perovskite.It is demonstrated that DMT,structurally similar to the“main-solvent”system(DMF and DMSO),possesses lower coordination ability with Pb2+and forms non-covalent interactions with the primary solvents.These interactions weaken the solvent-perovskite coordination without sacrificing solubility,thereby stabilizing homogeneous nucleation and promoting direct crystallization from the sol-gel phase toα-FAPbI3.As a result,the ambient-printed FAPbI3 films exhibited high quality,with more compact grain stacking,smoother morphology,higher phase purity,and fewer defects.Consequently,the resulting perovskite solar cells(0.062 cm2)and pero-SMs(15.64 cm2)fabricated via blade coating under ambient conditions achieved remarkable power conversion efficiencies(PCEs)of 24.46%and 22.54%,respectively.展开更多
High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping str...High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.展开更多
The vertical phase distribution of active layers plays a vital role in balancing exciton dissociation and cha rge transport for achieving efficient polymer solar cells(PSCs).The layer-by-layer(LbL)PSCs are commonly pr...The vertical phase distribution of active layers plays a vital role in balancing exciton dissociation and cha rge transport for achieving efficient polymer solar cells(PSCs).The layer-by-layer(LbL)PSCs are commonly prepared by using sequential spin-coating method from donor and acceptor solutions with distinct solvents and solvent additives.The enhanced exciton dissociation is expected in the LbL PSCs with efficient charge transport in the relatively neat donor or acceptor layers.In this work,a series of LbL all-polymer solar cells(APSCs)were fabricated with PM6 as donor and PY-DT as acceptor,and triplet material m-Ir(CPmPB)_(3)is deliberately incorporated into PY-DT layer to prolong exciton lifetimes of active layers.The power conversion efficiency(PCE)of LbL APSCs is improved to 18.24%from 17.32%by incorporating 0.3 wt%m-Ir(CPMPB)_(3)in PY-DT layer,benefiting from the simultaneously enhanced short-circuit current density(Isc)of 25.17 mA cm^(-2)and fill factor(FF)of 74.70%.The enhancement of PCE is attributed to the efficient energy transfer of m-Ir(CPmPB)_(3)to PM6 and PY-DT,resulting in the prolonged exciton lifetime in the active layer and the increased exciton diffusion distance.The efficient energy transfer from m-Ir(CPmPB)_(3)to PM6 and PY-DT layer can be confirmed by the increased photoluminescence(PL)intensity and the prolonged PL lifetime of PM6 and PY-DT in PM6+m-Ir(CPmPB)_(3)and PY-DT+m-Ir(CPmPB)_(3)films.This study indicates that the triplet material as solid additive has great potential in fabricating efficient LbL APSCs by prolonging exciton lifetimes in active layers.展开更多
基金supported by the National Natural Science Foundation of China(NSFC Grant Nos.62075029,52130304,62105055,62222503,62474028 and 52073040)The Fundamental Research Funds for the Central Universities(Program No.ZYGX2021J017)+5 种基金Sichuan Provincial Regional Innovation Cooperation Project(Program No.2022YFQ0078)Creative Research Groups of the National Natural Science Foundation of Sichuan Province(2023NSFSC1973)The Sichuan Science and Technology Program(Grant No.2024NSFSC0012,2024NSFSC1447)The Sichuan Science and Technology Program(Grant Nos.2024NSFSC1446)National Key R and D Program of China(2023YFB2604101)The China Postdoctoral Science Foundation(Grant Nos.2023M740504,GZC20230380)。
文摘Ideal nanoscale phase-separated morphology is the primary condition to obtain high photovoltaic conversion efficiency(PCE)and high stability of organic solar cells(OSCs).However,the differences in solubility,miscibility and crystallinity between donors and acceptors make it difficult to achieve the optimal active layer morphology of OSCs.Herein,the volatile solid additive 3,5-dibromotoluene(DTL)with strong electronegativity and dipole moment has been developed for OSCs.DTL can interact with the acceptor,modulating its crystallization and stacking,enhancing donor/acceptor miscibility,reducing trap density,inhibiting carrier recombination,and balancing charge transport.Notably,the introduction of DTL finely tunes the energy level of the accepto r,which greatly enhances the open-circuit voltage(V_(OC))of the device compared to the conventional additive 1,8-diiodooctane(DIO).As a result,the DTL-treated PM6:L8-BObased OSCs obtained a high PCE of 18.87%and enhanced stability.Furthermore,the PM6:PM1:L8-BO+DTL-based OSCs achieved a champion PCE of 19.11%.This work deepens the working mechanism of additive strategy for regulating the morphology and improving performance,providing an effective method for achieving high-performance OSCs.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4200302)the National Natural Science Foundation of China(Grant Nos.52325307,52273188,22075194)+1 种基金Department of Science and Technology of Jiangsu Province(No.BE2022023)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),Collaborative Innovation Center of Suzhou Nano Science and Technology,and the Key Laboratory of Polymeric Materials Design and Synthesis for Biomedical Function,Soochow University.
文摘Achieving high-performance perovskite solar modules(pero-SMs)over large areas under ambient conditions remains a significant barrier to the commercialization of perovskite photovoltaics.This challenge arises from the strong solvent-perovskite coordination interactions in the hygroscopic perovskite precursor ink,which complicate the control of nucleation-growth kinetics and phase evolution during film formation in the presence of moisture,thereby hindering the formation of high-quality perovskite films.In this work,a“vip-solvent”additive strategy was developed by incorporating N,N-dimethylthioformamide(DMT)into the perovskite precursor ink to effectively modulate the coordination between the solvent and perovskite.It is demonstrated that DMT,structurally similar to the“main-solvent”system(DMF and DMSO),possesses lower coordination ability with Pb2+and forms non-covalent interactions with the primary solvents.These interactions weaken the solvent-perovskite coordination without sacrificing solubility,thereby stabilizing homogeneous nucleation and promoting direct crystallization from the sol-gel phase toα-FAPbI3.As a result,the ambient-printed FAPbI3 films exhibited high quality,with more compact grain stacking,smoother morphology,higher phase purity,and fewer defects.Consequently,the resulting perovskite solar cells(0.062 cm2)and pero-SMs(15.64 cm2)fabricated via blade coating under ambient conditions achieved remarkable power conversion efficiencies(PCEs)of 24.46%and 22.54%,respectively.
基金supported in part by Science and Technology Project of State Grid Corporation of China,“Research on Harmonic Oscillation ProblemsSuppression Strategies of Flexible DC Connected to AC Grid”,(No.SGTYHT/17-JS-199).
文摘High-frequency resonance can occur when a modular multilevel converter(MMC)is inserted into an AC grid.Additional damping control is a relatively low-cost resonance suppression strategy compared to passive damping strategies.This paper analyzes the influences of a feed-forward voltage filter and feedback current filter for the inner controller for the high-frequency impedance characteristics of the MMC based on a model.Moreover,the mechanism,influencing factors,and limitations of the existing strategy including an additional lowpass filter in the voltage feed-forward stage are investigated.Secondly,a resonance suppression strategy for the inclusion of additional cascaded notch filters in the voltage feed-forward stage is proposed,and its parameter design method and applicable scenarios are analyzed.In addition,this paper analyzes the effects of the inclusion of an additional control in other stages for the inner controller of the MMC.Finally,the correctness of the theoretical analysis and the proposed strategy is verified based on the simulation of an actual project on PSCAD/EMTDC.
基金supported by Beijing Natural Science Foundation(4232073 and 1232029)the National Natural Science Foundation of China(62175011,62105017,62205276,and 5231101105)+4 种基金the Natural Science Foundation of Hebei Province(F2023105002)the National Research Foundation of Korea(2023K2A9A2A06059546)the support from the Hong Kong Research Grants Council(PolyU 15307321)RGC Senior Research Fellowship Scheme(SRFS2021–5S01)Research Institute for Smart Energy(CDAQ)。
文摘The vertical phase distribution of active layers plays a vital role in balancing exciton dissociation and cha rge transport for achieving efficient polymer solar cells(PSCs).The layer-by-layer(LbL)PSCs are commonly prepared by using sequential spin-coating method from donor and acceptor solutions with distinct solvents and solvent additives.The enhanced exciton dissociation is expected in the LbL PSCs with efficient charge transport in the relatively neat donor or acceptor layers.In this work,a series of LbL all-polymer solar cells(APSCs)were fabricated with PM6 as donor and PY-DT as acceptor,and triplet material m-Ir(CPmPB)_(3)is deliberately incorporated into PY-DT layer to prolong exciton lifetimes of active layers.The power conversion efficiency(PCE)of LbL APSCs is improved to 18.24%from 17.32%by incorporating 0.3 wt%m-Ir(CPMPB)_(3)in PY-DT layer,benefiting from the simultaneously enhanced short-circuit current density(Isc)of 25.17 mA cm^(-2)and fill factor(FF)of 74.70%.The enhancement of PCE is attributed to the efficient energy transfer of m-Ir(CPmPB)_(3)to PM6 and PY-DT,resulting in the prolonged exciton lifetime in the active layer and the increased exciton diffusion distance.The efficient energy transfer from m-Ir(CPmPB)_(3)to PM6 and PY-DT layer can be confirmed by the increased photoluminescence(PL)intensity and the prolonged PL lifetime of PM6 and PY-DT in PM6+m-Ir(CPmPB)_(3)and PY-DT+m-Ir(CPmPB)_(3)films.This study indicates that the triplet material as solid additive has great potential in fabricating efficient LbL APSCs by prolonging exciton lifetimes in active layers.
