Semiconducting two-dimensional conjugated polymers(2DCPs)with strong fluorescence emission have great potential for various optoelectronic applications.However,it is enormously challenging to achieve this goal due to ...Semiconducting two-dimensional conjugated polymers(2DCPs)with strong fluorescence emission have great potential for various optoelectronic applications.However,it is enormously challenging to achieve this goal due to the significant compact interlayerπ-πstacking-induced quenching effect in these systems.In this work,we found that highly fluorescent semiconducting 2DCPs can be prepared through an effective side-chain engineering approach in which interlayer spacers are introduced to reduce the fluorescence quenching effect.The obtained two truxene-based 2DCP films that,along with-C6H13 and-C_(12)H_(25)alkyl side chains as interlayer spacers both demonstrate superior fluorescence properties with a high photoluminescence quantum yield of 5.6%and 14.6%,respectively.These are among the highest values currently reported for 2DCP films.Moreover,an ultralong isotropic quasi-twodimensional exciton diffusion length constrained in the plane with its highest value approaching 110 nm was revealed by the transient photoluminescence microscopy technique,suggesting that theπ-conjugated structure in these truxene-based 2DCP films has effectively been extended.This work can enable a broad exploration of highly fluorescent semiconducting 2DCP films for more deeply fundamental properties and optoelectronic device applications.展开更多
Significant nonradiative energy loss and short exciton diffusion length in organic solar cells(OSCs)are two major obstacles to achieving state-of-the-art efficiencies.It is crucial to conduct a study on the intensive ...Significant nonradiative energy loss and short exciton diffusion length in organic solar cells(OSCs)are two major obstacles to achieving state-of-the-art efficiencies.It is crucial to conduct a study on the intensive mechanism and improvement strategies for future breakthroughs in the efficiency of OSCs.In this work,nonradiative energy loss and exciton diffusion length are optimized simultaneously by incorporating a vip acceptor(LA15)to construct ternary OSC(D18:L8-BO:LA15).Firstly,LA15 exhibits excellent compatibility with the host acceptor L8-BO,and effectively improves the fluorescence quantum efficiency(FLQY),resulting in suppressed non-radiative energy loss.Moreover,LA15 effectively prolongs the fluorescent lifetime of the acceptor phase from 0.85 to 1.12 ns,leading to larger exciton diffusion length,which is beneficial for reducing geminate recombination.Besides,the addition of LA15 optimizes the crystallinity of the active layer with amplified charge transport capacity.As a result,the optimized D18:L8-BO:LA15 device achieves ultralow nonradiative energy loss of 0.18 e V and improved fill factor(FF)with high efficiency up to 19.13%.These results highlight the crucial roles of regulating FLQYand exciton lifetime in achieving highefficiency OSCs.展开更多
The M-series molecules with a ladder-typefused-ring core are promising acceptors (A) for organic solarcells (OSCs) owing to their excellent optoelectronic propertiesand facile synthesis. To further optimize their phot...The M-series molecules with a ladder-typefused-ring core are promising acceptors (A) for organic solarcells (OSCs) owing to their excellent optoelectronic propertiesand facile synthesis. To further optimize their photovoltaicperformance, two M-series acceptors (M36 and M13) with si-milar chemical structures are judiciously selected and com-bined in a photoactive layer to construct ternary OSCs. It isfound that a homogeneous mixed phase can be formed in theacceptor mixture due to the good compatibility between M36and M13, affording an enlarged exciton diffusion length that isconducive to efficient exciton dissociation. After blendingwith the polymer donor (D) PM6, the resultant ternary activelayer exhibits a more favorable phase-separated micro-structure and enhanced crystalline ordering than M36- andM13-based binary systems, thus enabling improved carriertransport and reduced charge recombination. Consequently,significant increases in both fill factor and photocurrent areachieved for the ternary device compared to the two binaryreference devices, delivering a high power conversion effi-ciency of 17.4%, which is among the highest efficiencies re-ported for A-D-A-type acceptors-based OSCs so far.展开更多
Constructing ideal P-i-N-like network morphology and extending exciton diffusion length(L_(D))are considered bottleneck factors to further improve the power conversion efficiency(PCE)of organic photovoltaics(OPVs).How...Constructing ideal P-i-N-like network morphology and extending exciton diffusion length(L_(D))are considered bottleneck factors to further improve the power conversion efficiency(PCE)of organic photovoltaics(OPVs).However,simultaneous optimizations of the vertical phase separation morphology and L_(D)have rarely been reported.In this work,we apply a gradient thermal-annealing strategy to efficiently regulate the molecular stacking orientation and crystallinity of the polymer donor.The ordered molecular stacking significantly improves the exciton diffusion paths and enlarges the L_(D)from 19.47 nm(PM6-control)to 24.96 nm(PM6-target),enabling efficient exciton dissociation and charge transport.Moreover,the optimized crystallinity behavior inhibited PM6 film erosion from the upper acceptor solution.It ensured controlled donor-acceptor interpenetration,forming the desired pseudo planar heterojunction(PPHJ)structure.Eventually,benefiting from the ideal vertical morphology and the prolonged L_(D),the printing PPHJ(target)device achieves an outstanding PCE of 18.20%with suppressed non-radiative recombination losses(0.212 eV)and enhanced fill factor(78.2%),which is one of the top values for the reported eco-friendly printing binary OPVs.This study demonstrates a simple but feasible method to further improve the performance of polymer solar cells.展开更多
基金supported by the Ministry of Science and Technology of China(grant nos.2018YFA0703200 and 2022YFB3603800)the Natural Science Foundation of China(grant nos.21875259,52233010,51725304,61890943,and 22021002)+3 种基金the CAS Project for Young Scientists in Basic Research(grant no.YSBR-053)the Youth Innovation Promotion Association of the Chinese Academy of Sciences,the National Program for Support of Top-notch Young Professionals,the Beijing National Laboratory for Molecular Sciences(grant no.BNLMS-CXXM-202012)the Key Research Program of the Chinese Academy of Sciences(grant no.XDPB13)K.C.Wong Education Foundation(grant no.GJTD-2020-02).
文摘Semiconducting two-dimensional conjugated polymers(2DCPs)with strong fluorescence emission have great potential for various optoelectronic applications.However,it is enormously challenging to achieve this goal due to the significant compact interlayerπ-πstacking-induced quenching effect in these systems.In this work,we found that highly fluorescent semiconducting 2DCPs can be prepared through an effective side-chain engineering approach in which interlayer spacers are introduced to reduce the fluorescence quenching effect.The obtained two truxene-based 2DCP films that,along with-C6H13 and-C_(12)H_(25)alkyl side chains as interlayer spacers both demonstrate superior fluorescence properties with a high photoluminescence quantum yield of 5.6%and 14.6%,respectively.These are among the highest values currently reported for 2DCP films.Moreover,an ultralong isotropic quasi-twodimensional exciton diffusion length constrained in the plane with its highest value approaching 110 nm was revealed by the transient photoluminescence microscopy technique,suggesting that theπ-conjugated structure in these truxene-based 2DCP films has effectively been extended.This work can enable a broad exploration of highly fluorescent semiconducting 2DCP films for more deeply fundamental properties and optoelectronic device applications.
基金supported by the National Natural Science Foundation of China(22309098,62305350,22375213)Shandong Natural Science Foundation(ZR2022QF024)+1 种基金the Youth Innovation Promotion Association CAS(2021211)Shandong Energy Institute(SEIS202108)。
文摘Significant nonradiative energy loss and short exciton diffusion length in organic solar cells(OSCs)are two major obstacles to achieving state-of-the-art efficiencies.It is crucial to conduct a study on the intensive mechanism and improvement strategies for future breakthroughs in the efficiency of OSCs.In this work,nonradiative energy loss and exciton diffusion length are optimized simultaneously by incorporating a vip acceptor(LA15)to construct ternary OSC(D18:L8-BO:LA15).Firstly,LA15 exhibits excellent compatibility with the host acceptor L8-BO,and effectively improves the fluorescence quantum efficiency(FLQY),resulting in suppressed non-radiative energy loss.Moreover,LA15 effectively prolongs the fluorescent lifetime of the acceptor phase from 0.85 to 1.12 ns,leading to larger exciton diffusion length,which is beneficial for reducing geminate recombination.Besides,the addition of LA15 optimizes the crystallinity of the active layer with amplified charge transport capacity.As a result,the optimized D18:L8-BO:LA15 device achieves ultralow nonradiative energy loss of 0.18 e V and improved fill factor(FF)with high efficiency up to 19.13%.These results highlight the crucial roles of regulating FLQYand exciton lifetime in achieving highefficiency OSCs.
基金supported by the National Natural Science Foundation of China (52130306)the National Key R&D Program of China (2022YFB4200303)+2 种基金the Fundamental Research Funds for the Central Universities (2024300413)the Program of Youth Innovation Promotion Association CAS (2021299)Guangdong Basic and Applied Basic Research Foundation (2023A1515110044)。
文摘The M-series molecules with a ladder-typefused-ring core are promising acceptors (A) for organic solarcells (OSCs) owing to their excellent optoelectronic propertiesand facile synthesis. To further optimize their photovoltaicperformance, two M-series acceptors (M36 and M13) with si-milar chemical structures are judiciously selected and com-bined in a photoactive layer to construct ternary OSCs. It isfound that a homogeneous mixed phase can be formed in theacceptor mixture due to the good compatibility between M36and M13, affording an enlarged exciton diffusion length that isconducive to efficient exciton dissociation. After blendingwith the polymer donor (D) PM6, the resultant ternary activelayer exhibits a more favorable phase-separated micro-structure and enhanced crystalline ordering than M36- andM13-based binary systems, thus enabling improved carriertransport and reduced charge recombination. Consequently,significant increases in both fill factor and photocurrent areachieved for the ternary device compared to the two binaryreference devices, delivering a high power conversion effi-ciency of 17.4%, which is among the highest efficiencies re-ported for A-D-A-type acceptors-based OSCs so far.
基金supported by the National Natural Science Foundation of China(NSFC)(52333006 and 52303232)Jiangxi Provincial Natural Science Foundation(20242BAB20184)+1 种基金Graduate Innovation Fund of Jiangxi Province(YC2024-S267)Guangdong Basic and Applied Basic Research Foundation(2023A1515110160).
文摘Constructing ideal P-i-N-like network morphology and extending exciton diffusion length(L_(D))are considered bottleneck factors to further improve the power conversion efficiency(PCE)of organic photovoltaics(OPVs).However,simultaneous optimizations of the vertical phase separation morphology and L_(D)have rarely been reported.In this work,we apply a gradient thermal-annealing strategy to efficiently regulate the molecular stacking orientation and crystallinity of the polymer donor.The ordered molecular stacking significantly improves the exciton diffusion paths and enlarges the L_(D)from 19.47 nm(PM6-control)to 24.96 nm(PM6-target),enabling efficient exciton dissociation and charge transport.Moreover,the optimized crystallinity behavior inhibited PM6 film erosion from the upper acceptor solution.It ensured controlled donor-acceptor interpenetration,forming the desired pseudo planar heterojunction(PPHJ)structure.Eventually,benefiting from the ideal vertical morphology and the prolonged L_(D),the printing PPHJ(target)device achieves an outstanding PCE of 18.20%with suppressed non-radiative recombination losses(0.212 eV)and enhanced fill factor(78.2%),which is one of the top values for the reported eco-friendly printing binary OPVs.This study demonstrates a simple but feasible method to further improve the performance of polymer solar cells.
