Herein,two asymmetric hexacyclic fused small molecule acceptors(SMAs),namely BP4F-HU and BP4F-UU,were synthesized.The elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology...Herein,two asymmetric hexacyclic fused small molecule acceptors(SMAs),namely BP4F-HU and BP4F-UU,were synthesized.The elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology of blend film,thereby improving charge mobility and reducing energy loss within the corresponding film.Notably,the PM6:BP4F-UU device exhibited a higher open-circuit voltage(V_(oc))of 0.878 V compared to the PM6:BP4F-HU device with a V_(oc)of 0.863 V.Further,a new wide bandgap SMA named BTP-TA was designed and synthesized as the third component to the PM6:BP4F-UU host binary devices,which showed an ideal complementary absorption spectrum in PM6:BP4F-UU system.In addition,BTP-TA can achieve efficient intermolecular energy transfer to BP4F-UU by fluorescence resonance energy transfer(FRET)pathway,due to the good overlap between the photoluminescence(PL)spectrum of BTP-TA and the absorption region of BP4F-UU.Consequently,ternary devices with 15wt%BTP-TA exhibits broader photon utilization,optimal blend morphology,and reduced charge recombination compared to the corresponding binary devices.Consequently,PM6:BP4F-UU:BTP-TA ternary device achieved an optimal power conversion efficiency(PCE)of 17.83%with simultaneously increased V_(oc)of 0.905 V,short-circuit current density(J_(sc))of 26.14 mA/cm^(2),and fill factor(FF)of 75.38%.展开更多
Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy...Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.展开更多
Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a d...Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a deficiency in understanding the structure-property relationship.Herein,we investigated two low-cost terthiophene-based electron acceptors,namely,3TC8 and 3TEH,with 3,4-bis(octan-3-yloxy)thiophene,differing only in the alkylated thiophene-bridges.Both acceptors exhibit low optical gaps(∼1.43 eV)and possess deep highest occupied molecular orbital(HOMO)levels(∼−5.8 eV).Notably,the single-crystal structure of 3TEH demonstrates highly planar conjugated backbone and strongπ-πstacking between intermolecular terminal groups,attributed to the presence of the bulky alkylated noncovalently conformational locks.Upon utilizing both acceptors to fabricate OSCs,the 3TC8-based device exhibited a power conversion efficiency(PCE)of 11.1%,while the 3TEH-based OSC demonstrated an excellent PCE of 14.4%.This PCE is the highest among OSCs based on terthiophene-containing electron acceptors.These results offer a new strategy for designing low-cost electron acceptors for highly efficient OSCs.展开更多
Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increa...Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increasing optical absorption,refining energy levels,and improving molecular packing in organic semiconductors.Herein,a series of NFAs(Pz IC-4H,Pz IC-4F,Pz IC-4Cl,Pz IC-2Br)with phenazine as the central core and with/without halogen-substituted(dicyanomethylidene)-indan-1-one(IC)as the electron-accepting end group were synthesized,and the effect of end group matched phenazine central unit on the photovoltaic performance was systematically studied.Synergetic photophysical and morphological analyses revealed that the PM6:Pz IC-4F blend involves efficient exciton dissociation,higher charge collection and transfer rates,better crystallinity,and optimal phase separation.Therefore,OSCs based on PM6:Pz IC-4F as the active layer exhibited a PCE of 16.48%with an open circuit voltage(Voc)and energy loss of 0.880 V and 0.53 e V,respectively.Accordingly,this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs.展开更多
Design and synthesis of superior cost-effective non-fullerene acceptors(NFAs)are still big challenges for facilitating the commercialization of organic solar cells(OSCs),yet to be realized.Herein,two medium bandgap fu...Design and synthesis of superior cost-effective non-fullerene acceptors(NFAs)are still big challenges for facilitating the commercialization of organic solar cells(OSCs),yet to be realized.Herein,two medium bandgap fully non-fused ring electron acceptors(NFREAs,medium bandgap,i,e.,1,3-1,8 eV),namely PTR-2Cl and PTR-4Cl are synthesized with only four steps by using intramolecular noncovalent interaction central core,structured alkyl side chain orientation linking units and flanking with different electron-withdrawing end group.Among them,PTR-4C1 exhibits increased average electrostatic potential(ESP)difference with polymer donor,enhanced crystallinity and compactπ-πstacking compared with the control molecule PTR-2CI.As a result,the PTR-4Cl-based OSC achieved an impressive power conversion efficiency(PCE)of 14.72%,with a much higher open-circuit voltage(V_(OC))of 0.953 V and significantly improved fill factor(FF)of 0.758,demonstrating one of the best acceptor material in the top-performing fully NFREA-based OSCs with both high PCE and V_(OC).Notably,PTR-4Cl-based cells maintain a good T_80lifetime of its initial PCE after over 936 h under a continuous thermal annealing treatment and over1300 h T_(80)lifetime without encapsulation.This work provides a cost-effective design strategy for NFREAs on obtaining high V_(OC),efficient exciton dissociation,and ordered molecular packing and thus high-efficiency and stable OSCs.展开更多
The selection of photoactive layer materials for organic solar cells(OSCs) is essential for the photoelectric conversion process.It is well known that chlorophyll is an abundant pigment in nature and is extremely valu...The selection of photoactive layer materials for organic solar cells(OSCs) is essential for the photoelectric conversion process.It is well known that chlorophyll is an abundant pigment in nature and is extremely valuable for photosynthesis.However,there is little research on how to improve the efficiency of chlorophyll-based OSCs by matching chlorophyll derivatives with excellent non-fullerene acceptors to form heterojunctions.Therefore in this study we utilize a chlorophyll derivative,Ce_(6)Me_(3),as a donor material and investigate the performance of its heterojunction with acceptor materials.Through density functional theory,the photoelectric performances of acceptors,i ncluding the fullerene derivative PC_(71)BM and the terminal halogenated non-fullerene DTBCIC series,are compared in detail.It is found that DTBCIC-C1 has better planarity,light absorption,electron affinity,charge reorganization energy and charge mobility than others.Ce_(6)Me_(3) has good energy level matching and absorption spectral complementarity with the investigated acceptor molecules and also shows good electron donor properties.Furthermore,the designed Ce_(6)Me_(3)/DTBCIC interfaces have improved charge separation and reorganization rates(K_(CS)/K_(CR)) compared with the Ce_(6)Me_(3)/PC_(71)BM interface.This research provides a theoretical basis for the design of photoactive layer materials for chlorophyll-based OSCs.展开更多
Molecular engineering is a crucial strategy for improving the photovoltaic performance of dye-sensitized solar cells(DSSCs). Despite the common use of the donor-π bridge-acceptor architecture in designing sensitizers...Molecular engineering is a crucial strategy for improving the photovoltaic performance of dye-sensitized solar cells(DSSCs). Despite the common use of the donor-π bridge-acceptor architecture in designing sensitizers, the underlying structure-performance relationship remains not fully understood. In this study, we synthesized and characterized three sensitizers: MOTP-Pyc, MOS_(2)P-Pyc, and MOTS_(2)P-Pyc, all featuring a bipyrimidine acceptor. Absorption spectra, cyclic voltammetry, and transient photoluminescence spectra reveal a photo-induced electron transfer(PET) process in the excited sensitizers. Electron spin resonance spectroscopy confirmed the presence of charge-separated states. The varying donor and π-bridge structures among the three sensitizers led to differences in their conjugation effect, influencing light absorption abilities and PET processes and ultimately impacting the photovoltaic performance. Among the synthesized sensitizers, MOTP-Pyc demonstrated a DSSC efficiency of 3.04%. Introducing an additional thienothiophene block into the π-bridge improved the DSSC efficiency to 4.47% for MOTS_(2)P-Pyc. Conversely, replacing the phenyl group with a thienothiophene block reduced DSSC efficiency to 2.14% for MOS_(2)P-Pyc. Given the proton-accepting ability of the bipyrimidine module, we treated the dye-sensitized TiO_(2) photoanodes with hydroiodic acid(HI), significantly broadening the light absorption range. This treatment greatly enhanced the short-circuit current density of DSSCs owing to the enhanced electron-withdrawing ability of the acceptor. Consequently, the HI-treated MOTS_(2)P-Pyc-based DSSCs achieved the highest power conversion efficiency of 7.12%, comparable to that of the N719 dye at 7.09%. This work reveals the positive role of bipyrimidine in the design of organic sensitizers for DSSC applications.展开更多
Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acce...Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acceptors have emerged as promising materials for achieving highly efficient and stable binary OSCs,while application as third component for ternary OSCs is limited.Here a novelπ-extended giant dimeric acceptor,GDF,is developed based on central Y series core fusion and rigid BDT as linker,and then incorporated into the state-of-the-art PM1:PC6 system to construct ternary OSCs.The GDF has a near planar backbone,resulting in increasedπ-conjugation,excellent crystallinity,and good electron transport capacity.When GDF is introduced into the PM1:PC6 system,it ensues in a cascade like the lowest unoccupied molecular orbitals(LUMO)energy level alignment,a complementary absorption band with PM1 and PC6,higher and balanced hole and electron mobility,slightly smaller domain size,and a higher exciton dissociation probability for PM1:PC6:GDF(1:1.1:0.1)blend film.As a consequence,the PM1:PC6:GDF(1:1.1:0.1)ternary OSC achieves a champion PCE of 19.22%,with a significantly higher open-circuit voltage and short-circuit current density,compared to 18.45%for the PM1:PC6(1:1.2)binary OSC.Our findings show that employing aπ-extended giant dimeric acceptor as a third component significantly improves the photovoltaic performance of ternary OSCs.展开更多
Using the method of Picus and Beer invariants, general expressions are obtained for the total intensity I and the degree of circular polarization Рcirc.of the luminescence of GaAs-type semiconductors with the partici...Using the method of Picus and Beer invariants, general expressions are obtained for the total intensity I and the degree of circular polarization Рcirc.of the luminescence of GaAs-type semiconductors with the participation of shallow acceptor levels in a longitudinal magnetic field H. Special cases are analyzed depending on the value and direction of the magnetic field strength, as well as on the constants of the g-factor of the acceptor g1,g2and the conduction band electron ge. In the case of a strong magnetic field H// [100], [111], [110], a numerical calculation of the angular dependence of the quantities I and Рcirc.was performed for some critical values of g2/g1, at which Рcirc.exhibits a sharp anisotropy in the range from −100% to +100%, and the intensity of the crystal radiation along the magnetic field tends to a minimum value.展开更多
The emergence of Y6-type nonfullerene acceptors has greatly enhanced the power conversion efficiency(PCE)of organic solar cells(OSCs).However,which structural feature is responsible for the excellent photovoltaic perf...The emergence of Y6-type nonfullerene acceptors has greatly enhanced the power conversion efficiency(PCE)of organic solar cells(OSCs).However,which structural feature is responsible for the excellent photovoltaic performance is still under debate.In this study,two Y6-like acceptors BDOTP-1 and BDOTP-2 were designed.Different from previous Y6-type acceptors featuring an A–D–Aʹ–D–A structure,BDOTP-1,and BDOTP-2 have no electron-deficient Aʹfragment in the core unit.Instead,there is an electron-rich dibenzodioxine fragment in the core.Although this modification leads to a marked change in the molecular dipole moment,electrostatic potential,frontier orbitals,and energy levels,BDOTP acceptors retain similar three-dimensional packing capability as Y6-type acceptors due to the similar banana-shaped molecular configuration.BDOTP acceptors show good performance in OSCs.High PCEs of up to 18.51%(certified 17.9%)are achieved.This study suggests that the banana-shaped configuration instead of the A–D–Aʹ–D–A structure is likely to be the determining factor in realizing high photovoltaic performance.展开更多
The recently reported efficient polymerized small-molecule acceptors(PSMAs)usually adopt a regioregular backbone by polymerizing small-molecule acceptors precursors with a low-reactivity 5-brominated 3-(dicyanomethyli...The recently reported efficient polymerized small-molecule acceptors(PSMAs)usually adopt a regioregular backbone by polymerizing small-molecule acceptors precursors with a low-reactivity 5-brominated 3-(dicyanomethylidene)indan-1-one(IC)end group or its derivatives,leading to low molecular weight,and thus reduce active layer mechanical properties.Herein,a series of newly designed chlorinated PSMAs originating from isomeric IC end groups are developed by adjusting chlorinated positions and copolymerized sites on end groups to achieve high molecular weight,favorable intermolecular interaction,and improved physicochemical properties.Compared with regioregular PY2Se-Cl-o and PY2Se-Cl-m,regiorandom PY2Se-Cl-ran has a similar absorption profile,moderate lowest unoccupied molecular orbital level,and favorable intermolecular packing and crystallization properties.Moreover,the binary PM6:PY2Se-Cl-ran blend achieves better ductility with a crack-onset strain of 17.5% and improved power conversion efficiency(PCE)of 16.23% in all-polymer solar cells(all-PSCs)due to the higher molecular weight of PY2Se-Cl-ran and optimized blend morphology,while the ternary PM6:J71:PY2Se-Cl-ran blend offers an impressive PCE approaching 17% and excellent device stability,which are all crucial for potential practical applications of all-PSCs in wearable electronics.To date,the efficiency of 16.86% is the highest value reported for the regiorandom PSMAs-based all-PSCs and is also one of the best values reported for the all-PSCs.Our work provides a new perspective to develop efficient all-PSCs,with all high active layer ductility,impressive PCE,and excellent device stability,towards practical applications.展开更多
Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE dr...Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development.展开更多
Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deproton...Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deprotonation kinetics and inherent adsorption energy scaling relations.Herein,we construct a tunable proton acceptor(TPA)on oxyhydroxides by in-situ reconstruction of metal oxoacids such as NiC2O4to accelerate deprotonation and break adsorption energy scaling relations during OER.The modified C_(2)O_(4)^(2-)as a TPA can easily extract H of*OH(forming*HC2O4intermediate)and then promote deprotonation by the transmitted hydrogen bond with*OOH along conjugated(H...)O=C-O(-H)chain.As a result,Ni OOH-C2O4shows non-concerted proton-electron transfer and improved deprotonation rate,and delivers a good OER activity(270 mV@10 mA cm-2).The conjugate acidity coefficient(pKa)of the modified oxoacid group can be a descriptor for TPA selection.This TPA strategy can be universally applied to Co-,Fe-,and Ni-based oxyhydroxides to facilitate OER efficiency.展开更多
Starting from the groundbreaking work in graphene[1],the active research in two-dimensional(2D)layered materials has unveiled a number of exotic phenomena that are unique in the 2D limit.In addition to the semimetal g...Starting from the groundbreaking work in graphene[1],the active research in two-dimensional(2D)layered materials has unveiled a number of exotic phenomena that are unique in the 2D limit.In addition to the semimetal graphene,the semiconducting transition metal dichalcogenides(TMDs)and the insulating hexagonal boron nitride(hBN)are also the main driving forces of the field.展开更多
Organic solar cells(OSCs)processed without halogenated solvents and complex treatments are essential for future commercialization.Herein,we report three novel small molecule acceptors(NFAs)consisting of a Y6-like core...Organic solar cells(OSCs)processed without halogenated solvents and complex treatments are essential for future commercialization.Herein,we report three novel small molecule acceptors(NFAs)consisting of a Y6-like core but withπ-extended naphthalene with progressively more chlorinated end-capping groups and a longer branched chain on the Nitrogen atom.These NFAs exhibit good solubilities in nonchlorinated organic solvents,broad optical absorptions,closeπ-πstacking distances(3.63–3.84A),and high electron mobilities(~10^(-3)cm^(2)V^(-1)s^(-1)).The o-xylene processed and as-cast binary devices using PM6 as the donor polymer exhibit a PCE increasing upon progressive chlorination of the naphthalene end-capping group from 8.93%for YN to 14.38%for YN-Cl to 15.00%for YN-2Cl.Furthermore similarly processed ternary OSCs were fabricated by employing YN-Cl and YN-2Cl as the third component of PM6:CH1007 blends(PCE=15.75%).Compared to all binary devices,the ternary PM6:CH1007:YN-Cl(1:1:0.2)and PM6:CH1007:YN-2Cl(1:1:0.2)cells exhibit significantly improved PCEs of 16.49%and15.88%,respectively,which are among the highest values reported to date for non-halogenated solvent processed OSCs without using any additives and blend post-deposition treatments.展开更多
Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was c...Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.展开更多
基金the National Natural Science Foundation of China(Nos.52125306 and 21875286)。
文摘Herein,two asymmetric hexacyclic fused small molecule acceptors(SMAs),namely BP4F-HU and BP4F-UU,were synthesized.The elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology of blend film,thereby improving charge mobility and reducing energy loss within the corresponding film.Notably,the PM6:BP4F-UU device exhibited a higher open-circuit voltage(V_(oc))of 0.878 V compared to the PM6:BP4F-HU device with a V_(oc)of 0.863 V.Further,a new wide bandgap SMA named BTP-TA was designed and synthesized as the third component to the PM6:BP4F-UU host binary devices,which showed an ideal complementary absorption spectrum in PM6:BP4F-UU system.In addition,BTP-TA can achieve efficient intermolecular energy transfer to BP4F-UU by fluorescence resonance energy transfer(FRET)pathway,due to the good overlap between the photoluminescence(PL)spectrum of BTP-TA and the absorption region of BP4F-UU.Consequently,ternary devices with 15wt%BTP-TA exhibits broader photon utilization,optimal blend morphology,and reduced charge recombination compared to the corresponding binary devices.Consequently,PM6:BP4F-UU:BTP-TA ternary device achieved an optimal power conversion efficiency(PCE)of 17.83%with simultaneously increased V_(oc)of 0.905 V,short-circuit current density(J_(sc))of 26.14 mA/cm^(2),and fill factor(FF)of 75.38%.
基金supported by the National Natural Sci-ence Foundation of China(22272081),Jiangsu Provincial Specially Appointed Professors Foundation.
文摘Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.
基金supported by the Beijing Natural Science Foundation of China(Z230019,2212005)the National Natural Science Foundation of China(NSFC 22173062,21833005,22090022 and 22275125).
文摘Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a deficiency in understanding the structure-property relationship.Herein,we investigated two low-cost terthiophene-based electron acceptors,namely,3TC8 and 3TEH,with 3,4-bis(octan-3-yloxy)thiophene,differing only in the alkylated thiophene-bridges.Both acceptors exhibit low optical gaps(∼1.43 eV)and possess deep highest occupied molecular orbital(HOMO)levels(∼−5.8 eV).Notably,the single-crystal structure of 3TEH demonstrates highly planar conjugated backbone and strongπ-πstacking between intermolecular terminal groups,attributed to the presence of the bulky alkylated noncovalently conformational locks.Upon utilizing both acceptors to fabricate OSCs,the 3TC8-based device exhibited a power conversion efficiency(PCE)of 11.1%,while the 3TEH-based OSC demonstrated an excellent PCE of 14.4%.This PCE is the highest among OSCs based on terthiophene-containing electron acceptors.These results offer a new strategy for designing low-cost electron acceptors for highly efficient OSCs.
基金financially supported by the National Natural Science Foundation of China (22279152,U21A20331)the National Science Fund for Distinguished Young Scholars (21925506)+1 种基金the Ningbo key scientific and technological project (2022Z117)the Ningbo Natural Science Foundation (2021J192)。
文摘Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increasing optical absorption,refining energy levels,and improving molecular packing in organic semiconductors.Herein,a series of NFAs(Pz IC-4H,Pz IC-4F,Pz IC-4Cl,Pz IC-2Br)with phenazine as the central core and with/without halogen-substituted(dicyanomethylidene)-indan-1-one(IC)as the electron-accepting end group were synthesized,and the effect of end group matched phenazine central unit on the photovoltaic performance was systematically studied.Synergetic photophysical and morphological analyses revealed that the PM6:Pz IC-4F blend involves efficient exciton dissociation,higher charge collection and transfer rates,better crystallinity,and optimal phase separation.Therefore,OSCs based on PM6:Pz IC-4F as the active layer exhibited a PCE of 16.48%with an open circuit voltage(Voc)and energy loss of 0.880 V and 0.53 e V,respectively.Accordingly,this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs.
基金the financial support by Hong Kong Scholar program(XJ2021-038)Young Talent Fund of Xi’an Association for Science and Technology(959202313080)+6 种基金the Natural Science Foundation Research Project of Shaanxi Province(2022JM-269)the Postgraduate Innovation and Practical Ability Training Program of Xi’an Shiyou University(YCS21212144)the National Natural Science Foundation of China(52103221,52172048,12175298)the Shandong Provincial Natural Science Foundation(ZR2021QB179,ZR2021QB024,ZR2021ZD06)the Guangdong Natural Science Foundation of China(2023A1515012323,2023A1515010943)the National Key Research and Development Program of China(2022YFB4200400)funded by MOSTthe Fundamental Research Funds of Shandong University。
文摘Design and synthesis of superior cost-effective non-fullerene acceptors(NFAs)are still big challenges for facilitating the commercialization of organic solar cells(OSCs),yet to be realized.Herein,two medium bandgap fully non-fused ring electron acceptors(NFREAs,medium bandgap,i,e.,1,3-1,8 eV),namely PTR-2Cl and PTR-4Cl are synthesized with only four steps by using intramolecular noncovalent interaction central core,structured alkyl side chain orientation linking units and flanking with different electron-withdrawing end group.Among them,PTR-4C1 exhibits increased average electrostatic potential(ESP)difference with polymer donor,enhanced crystallinity and compactπ-πstacking compared with the control molecule PTR-2CI.As a result,the PTR-4Cl-based OSC achieved an impressive power conversion efficiency(PCE)of 14.72%,with a much higher open-circuit voltage(V_(OC))of 0.953 V and significantly improved fill factor(FF)of 0.758,demonstrating one of the best acceptor material in the top-performing fully NFREA-based OSCs with both high PCE and V_(OC).Notably,PTR-4Cl-based cells maintain a good T_80lifetime of its initial PCE after over 936 h under a continuous thermal annealing treatment and over1300 h T_(80)lifetime without encapsulation.This work provides a cost-effective design strategy for NFREAs on obtaining high V_(OC),efficient exciton dissociation,and ordered molecular packing and thus high-efficiency and stable OSCs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12074059, 11974152, and 11404055)Heilongjiang Postdoctoral Fund (Grant No. LBH-Q21061)。
文摘The selection of photoactive layer materials for organic solar cells(OSCs) is essential for the photoelectric conversion process.It is well known that chlorophyll is an abundant pigment in nature and is extremely valuable for photosynthesis.However,there is little research on how to improve the efficiency of chlorophyll-based OSCs by matching chlorophyll derivatives with excellent non-fullerene acceptors to form heterojunctions.Therefore in this study we utilize a chlorophyll derivative,Ce_(6)Me_(3),as a donor material and investigate the performance of its heterojunction with acceptor materials.Through density functional theory,the photoelectric performances of acceptors,i ncluding the fullerene derivative PC_(71)BM and the terminal halogenated non-fullerene DTBCIC series,are compared in detail.It is found that DTBCIC-C1 has better planarity,light absorption,electron affinity,charge reorganization energy and charge mobility than others.Ce_(6)Me_(3) has good energy level matching and absorption spectral complementarity with the investigated acceptor molecules and also shows good electron donor properties.Furthermore,the designed Ce_(6)Me_(3)/DTBCIC interfaces have improved charge separation and reorganization rates(K_(CS)/K_(CR)) compared with the Ce_(6)Me_(3)/PC_(71)BM interface.This research provides a theoretical basis for the design of photoactive layer materials for chlorophyll-based OSCs.
基金supported by the National Natural Science Foundation of China(Nos.21776207 and 21576195)。
文摘Molecular engineering is a crucial strategy for improving the photovoltaic performance of dye-sensitized solar cells(DSSCs). Despite the common use of the donor-π bridge-acceptor architecture in designing sensitizers, the underlying structure-performance relationship remains not fully understood. In this study, we synthesized and characterized three sensitizers: MOTP-Pyc, MOS_(2)P-Pyc, and MOTS_(2)P-Pyc, all featuring a bipyrimidine acceptor. Absorption spectra, cyclic voltammetry, and transient photoluminescence spectra reveal a photo-induced electron transfer(PET) process in the excited sensitizers. Electron spin resonance spectroscopy confirmed the presence of charge-separated states. The varying donor and π-bridge structures among the three sensitizers led to differences in their conjugation effect, influencing light absorption abilities and PET processes and ultimately impacting the photovoltaic performance. Among the synthesized sensitizers, MOTP-Pyc demonstrated a DSSC efficiency of 3.04%. Introducing an additional thienothiophene block into the π-bridge improved the DSSC efficiency to 4.47% for MOTS_(2)P-Pyc. Conversely, replacing the phenyl group with a thienothiophene block reduced DSSC efficiency to 2.14% for MOS_(2)P-Pyc. Given the proton-accepting ability of the bipyrimidine module, we treated the dye-sensitized TiO_(2) photoanodes with hydroiodic acid(HI), significantly broadening the light absorption range. This treatment greatly enhanced the short-circuit current density of DSSCs owing to the enhanced electron-withdrawing ability of the acceptor. Consequently, the HI-treated MOTS_(2)P-Pyc-based DSSCs achieved the highest power conversion efficiency of 7.12%, comparable to that of the N719 dye at 7.09%. This work reveals the positive role of bipyrimidine in the design of organic sensitizers for DSSC applications.
基金supported by the Yunnan Fundamental Research Project(202301BF070001-009,KC-22222357)the Sichuan Science and Technology Program(2023NSFSC0990)the School of Materials Science and Engineering,Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications。
文摘Ternary strategy with a suitable third component is a successful strategy to improve the photovoltaic performance of organic solar cells(OSCs).Very recently,Y-series based giant molecule acceptors or oligomerized acceptors have emerged as promising materials for achieving highly efficient and stable binary OSCs,while application as third component for ternary OSCs is limited.Here a novelπ-extended giant dimeric acceptor,GDF,is developed based on central Y series core fusion and rigid BDT as linker,and then incorporated into the state-of-the-art PM1:PC6 system to construct ternary OSCs.The GDF has a near planar backbone,resulting in increasedπ-conjugation,excellent crystallinity,and good electron transport capacity.When GDF is introduced into the PM1:PC6 system,it ensues in a cascade like the lowest unoccupied molecular orbitals(LUMO)energy level alignment,a complementary absorption band with PM1 and PC6,higher and balanced hole and electron mobility,slightly smaller domain size,and a higher exciton dissociation probability for PM1:PC6:GDF(1:1.1:0.1)blend film.As a consequence,the PM1:PC6:GDF(1:1.1:0.1)ternary OSC achieves a champion PCE of 19.22%,with a significantly higher open-circuit voltage and short-circuit current density,compared to 18.45%for the PM1:PC6(1:1.2)binary OSC.Our findings show that employing aπ-extended giant dimeric acceptor as a third component significantly improves the photovoltaic performance of ternary OSCs.
文摘Using the method of Picus and Beer invariants, general expressions are obtained for the total intensity I and the degree of circular polarization Рcirc.of the luminescence of GaAs-type semiconductors with the participation of shallow acceptor levels in a longitudinal magnetic field H. Special cases are analyzed depending on the value and direction of the magnetic field strength, as well as on the constants of the g-factor of the acceptor g1,g2and the conduction band electron ge. In the case of a strong magnetic field H// [100], [111], [110], a numerical calculation of the angular dependence of the quantities I and Рcirc.was performed for some critical values of g2/g1, at which Рcirc.exhibits a sharp anisotropy in the range from −100% to +100%, and the intensity of the crystal radiation along the magnetic field tends to a minimum value.
基金the open research fund of the Songshan Lake Materials Laboratory(2021SLABFK02)the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51922032 and 21961160720).
文摘The emergence of Y6-type nonfullerene acceptors has greatly enhanced the power conversion efficiency(PCE)of organic solar cells(OSCs).However,which structural feature is responsible for the excellent photovoltaic performance is still under debate.In this study,two Y6-like acceptors BDOTP-1 and BDOTP-2 were designed.Different from previous Y6-type acceptors featuring an A–D–Aʹ–D–A structure,BDOTP-1,and BDOTP-2 have no electron-deficient Aʹfragment in the core unit.Instead,there is an electron-rich dibenzodioxine fragment in the core.Although this modification leads to a marked change in the molecular dipole moment,electrostatic potential,frontier orbitals,and energy levels,BDOTP acceptors retain similar three-dimensional packing capability as Y6-type acceptors due to the similar banana-shaped molecular configuration.BDOTP acceptors show good performance in OSCs.High PCEs of up to 18.51%(certified 17.9%)are achieved.This study suggests that the banana-shaped configuration instead of the A–D–Aʹ–D–A structure is likely to be the determining factor in realizing high photovoltaic performance.
基金National Natural Science Foundation of China,Grant/Award Numbers:21704082,21875182,22005121Key Scientific and Technological Innovation Team Project of Shaanxi Province,Grant/Award Number:2020TD‐002111 project 2.0,Grant/Award Number:BP2018008。
文摘The recently reported efficient polymerized small-molecule acceptors(PSMAs)usually adopt a regioregular backbone by polymerizing small-molecule acceptors precursors with a low-reactivity 5-brominated 3-(dicyanomethylidene)indan-1-one(IC)end group or its derivatives,leading to low molecular weight,and thus reduce active layer mechanical properties.Herein,a series of newly designed chlorinated PSMAs originating from isomeric IC end groups are developed by adjusting chlorinated positions and copolymerized sites on end groups to achieve high molecular weight,favorable intermolecular interaction,and improved physicochemical properties.Compared with regioregular PY2Se-Cl-o and PY2Se-Cl-m,regiorandom PY2Se-Cl-ran has a similar absorption profile,moderate lowest unoccupied molecular orbital level,and favorable intermolecular packing and crystallization properties.Moreover,the binary PM6:PY2Se-Cl-ran blend achieves better ductility with a crack-onset strain of 17.5% and improved power conversion efficiency(PCE)of 16.23% in all-polymer solar cells(all-PSCs)due to the higher molecular weight of PY2Se-Cl-ran and optimized blend morphology,while the ternary PM6:J71:PY2Se-Cl-ran blend offers an impressive PCE approaching 17% and excellent device stability,which are all crucial for potential practical applications of all-PSCs in wearable electronics.To date,the efficiency of 16.86% is the highest value reported for the regiorandom PSMAs-based all-PSCs and is also one of the best values reported for the all-PSCs.Our work provides a new perspective to develop efficient all-PSCs,with all high active layer ductility,impressive PCE,and excellent device stability,towards practical applications.
基金the support from the NSFC (22209131, 22005121, 21875182, and 52173023)National Key Research and Development Program of China (2022YFE0132400)+4 种基金Key Scientific and Technological Innovation Team Project of Shaanxi Province (2020TD-002)111 project 2.0 (BP0618008)Open Fund of Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications (Changzhou University, GDRGCS2022002)Open Fund of Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education (Jiangxi Normal University, KFSEMC-202201)acquired at beamlines 7.3.3 and 11.0.1.2 at the Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC0205CH11231
文摘Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development.
基金the support from the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(22278307,22222808,21978200)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deprotonation kinetics and inherent adsorption energy scaling relations.Herein,we construct a tunable proton acceptor(TPA)on oxyhydroxides by in-situ reconstruction of metal oxoacids such as NiC2O4to accelerate deprotonation and break adsorption energy scaling relations during OER.The modified C_(2)O_(4)^(2-)as a TPA can easily extract H of*OH(forming*HC2O4intermediate)and then promote deprotonation by the transmitted hydrogen bond with*OOH along conjugated(H...)O=C-O(-H)chain.As a result,Ni OOH-C2O4shows non-concerted proton-electron transfer and improved deprotonation rate,and delivers a good OER activity(270 mV@10 mA cm-2).The conjugate acidity coefficient(pKa)of the modified oxoacid group can be a descriptor for TPA selection.This TPA strategy can be universally applied to Co-,Fe-,and Ni-based oxyhydroxides to facilitate OER efficiency.
文摘Starting from the groundbreaking work in graphene[1],the active research in two-dimensional(2D)layered materials has unveiled a number of exotic phenomena that are unique in the 2D limit.In addition to the semimetal graphene,the semiconducting transition metal dichalcogenides(TMDs)and the insulating hexagonal boron nitride(hBN)are also the main driving forces of the field.
基金supported by the National Natural Science Foundation of China(61804073)the Center for Light Energy Activated Redox Processes(LEAP),an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,under award DE-SC0001059+3 种基金the Mat CI Facility which receives support from the National Science Foundation MRSEC Program(NSF DMR-1720139)of the Materials Research Center at Northwestern Universitysupport from the US Office of Naval Research Contract N00014-20-1-2116the U.S.Department of Energy under contract No.DE-AC02-05CH11231at beamline 8-ID-E of the Advanced Photon Source,a U.S.Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No.DE-AC0206CH11357。
文摘Organic solar cells(OSCs)processed without halogenated solvents and complex treatments are essential for future commercialization.Herein,we report three novel small molecule acceptors(NFAs)consisting of a Y6-like core but withπ-extended naphthalene with progressively more chlorinated end-capping groups and a longer branched chain on the Nitrogen atom.These NFAs exhibit good solubilities in nonchlorinated organic solvents,broad optical absorptions,closeπ-πstacking distances(3.63–3.84A),and high electron mobilities(~10^(-3)cm^(2)V^(-1)s^(-1)).The o-xylene processed and as-cast binary devices using PM6 as the donor polymer exhibit a PCE increasing upon progressive chlorination of the naphthalene end-capping group from 8.93%for YN to 14.38%for YN-Cl to 15.00%for YN-2Cl.Furthermore similarly processed ternary OSCs were fabricated by employing YN-Cl and YN-2Cl as the third component of PM6:CH1007 blends(PCE=15.75%).Compared to all binary devices,the ternary PM6:CH1007:YN-Cl(1:1:0.2)and PM6:CH1007:YN-2Cl(1:1:0.2)cells exhibit significantly improved PCEs of 16.49%and15.88%,respectively,which are among the highest values reported to date for non-halogenated solvent processed OSCs without using any additives and blend post-deposition treatments.
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT)(2022R1F1A1065586,2019R1A6A1A11053838)the GIST Research Institute(GRI)APRI grant funded by the GIST in 2022.
文摘Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.