Solving the problems of low electrical conductivity and poor cycling durability in transition metal oxidesbased anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has already turned into an u...Solving the problems of low electrical conductivity and poor cycling durability in transition metal oxidesbased anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has already turned into an urgent requirement.In this paper,we successfully synthesized Co_(2)VO_(4)/Co compounds with Co-VMOF(metal-organic framework)as a sacrificial template and investigated their electrochemical mechanism in order to improve the electrochemical properties of LIBs and SIBs.The optimized heaping configuration and the existence of metallic Co catalyzed the formation of radical ions,thereby facilitating higher conductivity,shortening Li+and Na+transport paths,and providing more active sites.Co_(2)VO_(4)/Co constructed with 2-methylimidazole as a ligand showed a discharge capacity of 1605.1 mA h g^(-1)after 300 cycles at 0.1 A g^(-1)in LIB and 677.2 mA h g^(-1)in SIB.Density functional theory(DFT)calculation emphasizes the crucial role of Co_(2)VO_(4)/Co in enhancing electrode conductivity,decreasing the migratory energy barrier,and thereby strengthening electrochemical properties.This heterostructure building technique may pave the way for the development of high-performance LIBs and SIBs.Furthermore,the problem of the low first-loop coulombic efficiency faced by transition metal oxides is improved.展开更多
Although two-dimensional perovskite devices are highly stable,they also lead to a number of challenges.For instance,the introduction of large organic amines makes crystallization process complicated,causing problems s...Although two-dimensional perovskite devices are highly stable,they also lead to a number of challenges.For instance,the introduction of large organic amines makes crystallization process complicated,causing problems such as generally small grain size and blocked charge transfer.In this work,imprint assisted with methylamine acetate were used to improve the morphology of the film,optimize the internal phase distribution,and enhance the charge transfer of the perovskite film.Specifically,imprint promoted the dispersion of spacer cations in the recrystallization process with the assistance of methylamine acetate,thus inhibited the formation of low-n phase induced by the aggregation of spacer cations and facilitated the formation of 3D-like phase.In this case,the corresponding quasi-2D perovskite solar cells delivered improved efficiency and exhibited superior stability.Our work provides an effective strategy to obtain uniform phase distribution for quasi-2D perovskite.展开更多
The rational synthesis of a two-dimensional(2D)porous aromatic framework(PAF)with a controllable growth direction remains a challenge to overcome the limitation of traditional stacked 2D materials.Herein,a step-growth...The rational synthesis of a two-dimensional(2D)porous aromatic framework(PAF)with a controllable growth direction remains a challenge to overcome the limitation of traditional stacked 2D materials.Herein,a step-growth strategy is developed to fabricate a vertically oriented nitrogen-rich porous aromatic framework on graphene oxide(V-PAF-GO)using monolayer benzidine-functionalized GO(BZ-GO)as a molecular pillar.Then,the confined Co nanoparticle(NP)catalysts are synthesized by encapsulating ultra-small Co into the slit pores of V-PAF-GO.Due to the high nitrogen content,large specific surface area,and adequate slit pores,the optimized vertical nanocomposites V-PAF-GO provide abundant anchoring sites for metal NPs,leading to ultrafine Co NPs(1.4 nm).The resultant Co/V-PAF-GO catalyst shows an extraordinary catalytic activity for ammonia borane(AB)methanolysis,yielding a turnover frequency value of 47.6 min−1 at 25°C,comparable to the most effective non-noble-metal catalysts ever reported for AB methanolysis.Experimental and density functional theory studies demonstrate that the electron-donating effect of N species of PAF positively corresponds to the low barrier in methanol molecule activation,and the cleavage of the O–H bond in CH3OH has been proven to be the rate-determining step for AB methanolysis.This work presents a versatile step-growth strategy to prepare a vertically oriented PAF on GO to solve the stacking problem of 2D materials,which will be used to fabricate other novel 2D or 2D–2D materials with controllable orientation for various 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
LiFePO_(4),as a prevailing cathode material for lithium-ion batteries(LIBs),still encounters issues such as intrinsic poor electronic conductivity,inferior Li-ion diffusion kinetic,and two-phase transformation mechani...LiFePO_(4),as a prevailing cathode material for lithium-ion batteries(LIBs),still encounters issues such as intrinsic poor electronic conductivity,inferior Li-ion diffusion kinetic,and two-phase transformation mechanism involving substantial structural rearrangements,resulting in unsatisfactory rate performance.Carbon coating,cation doping,and morphological control have been widely employed to reconcile these issues.Inspired by these,we propose a synthetic route with metal–organic frameworks(MOFs)as self-sacrificial templates to simultaneously realize shape modulation,Mn doping,and N-doped carbon coating for enhanced electrochemical performances.The as-synthesized Li MnxFe1–xPO4/C(x=0,0.25,and0.5)deliver tunable electrochemical behaviors induced by the MOF templates,among which LiMn_(0.25)Fe_(0.75)PO_(4)/C outperforms its counterparts in cyclability(164.7 mA h g^(-1)after 200 cycles at 0.5 C)and rate capability(116.3 mA h g^(-1)at 10 C).Meanwhile,the ex-situ XRD reveals a dominant single-phase solid solution mechanism of LiMn_(0.25)Fe_(0.75)PO_(4)/C during delithiation,contrary to the pristine LiFePO_(4),without major structural reconstruction,which helps to explain the superior rate performance.Furthermore,the density functional theory(DFT)calculations verify the effects of Mn doping and embody the superiority of LiMn_(0.25)Fe_(0.75)PO_(4)/C as a LIB cathode,which well supports the experimental observations.This work provides insightful guidance for the design of tunable MOF-derived mixed transitionmetal systems for advanced LIBs.展开更多
Despite the dazzling theoretical capacity,the devasting electrochemical activity of Li_(2)MnO_(3)(LMO)caused by the difficult oxidation of Mn4+impedes its practical application as the lithium-ion battery(LIB)cathode.T...Despite the dazzling theoretical capacity,the devasting electrochemical activity of Li_(2)MnO_(3)(LMO)caused by the difficult oxidation of Mn4+impedes its practical application as the lithium-ion battery(LIB)cathode.The efficacious activation of the Li_(2)MnO_(3) by importing electrochemically active Mn3+ions or morphological engineering is instrumental to its lithium storage activity and structural integrity upon cycling.Herein,we propose a conceptual strategy with metal-organic frameworks(MOFs)as self-sacrificial templates to prepare oxygen-deficient Li_(2)MnO_(3)(O_v-LMO)for exalted lithium storage performance.Attributed to optimized morphological features,LMO materials derived from Mn-BDC(H_(2)BDC=1,4-dicarboxybenzene)delivered superior cycling/rate performances compared with their counterparts derived from Mn-BTC(H_(3)BTC=1,3,5-benzenetricarboxylicacid)and Mn-PTC(H_(4)PTC=pyromellitic acid).Both experimental and theoretical studies elucidate the efficacious activation of primitive LMO materials toward advanced lithium storage by importing oxygen deficiencies.Impressively,O_v-LMO derived from Mn-BDC(O_v-BDC-LMO)delivered intriguing reversible capacities(179.2 mA h g^(-1)at 20 mA g^(-1)after 200 cycles and 100.1 mA h g^(-1)at 80 mA g^(-1)after 300 cycles),which can be attributed to the small particle size that shortens pathways for Li+/electron transport,the enhanced redox activity induced by abundant oxygen vacancies,and the optimized electronic configuration that contributes to the faster lithium diffusivity.This work provides insights into the rational design of LMO by morphological and atomic modulation to direct its activation and practical application as an advanced LIB cathode.展开更多
For a polymer/polymer dismissible blend with two crystallizable components,the crystallization behavior of different components and the reciprocal influences between different crystals are interesting and important,bu...For a polymer/polymer dismissible blend with two crystallizable components,the crystallization behavior of different components and the reciprocal influences between different crystals are interesting and important,but did not investigate in detail.In this study,the L-poly(lactic acid)/polypropylene(PLLA/PP)blends with different weight ratios were prepared by melt mixing and the crystallization behavior of the blends were investigated.Results showed that the crystalline structures of PLLA and PP were not altered by the composition.For the crystallization of PLLA,both the diffusion of chain segments and crystallization rate were enhanced under the existence of PP crystals.For the crystallization of PP,its crystallization rate was depressed under the existence of amorphous PLLA molecular chains.When the PP crystallized from the existence of PLLA crystals,although the diffusion rate of PP was reduced by PLLA crystals,the nucleation positions were obviously enhanced,which accelerated the formation of PP crystals.This investigation would supply more basic data for the application of PLLA/PP blend.展开更多
Incorporation of siloxane-functionalized units into polymers backbone has proven to be an efficient strategy to improve photovoltaic performance. In this work, a low-cost siloxane-containing unit was developed to cons...Incorporation of siloxane-functionalized units into polymers backbone has proven to be an efficient strategy to improve photovoltaic performance. In this work, a low-cost siloxane-containing unit was developed to construct a series of terpolymers, and the effects of siloxane on the polymer performance were systematically studied. Different contents of thiophene containing siloxane-functionalized side chain were introduced into PM6 to obtain a series of polymers(PM6, PM6-SiO-10, PM6-SiO-20 and PM6-SiO-30). The siloxane-functionalized side chains in polymers have only a slight effect on the absorption behavior and frontier molecular orbitals. However, when the siloxane content increased, the terpolymers' aggregation property decreased and the temperature-dependency increased, leading to improved donor-acceptor compatibility. The power conversion efficiency(PCE) based on PM6:Y6, PM6-SiO-20:Y6 and PM6-SiO-30:Y6 devices was 15.64%, 16.03% and 15.82%, respectively. In comparison, the active layer based on PM6-SiO-10:Y6 exhibits the most appropriate phase separation morphology, resulting in effective exciton dissociation, more balanced hole-electron transport and less recombination. Consequently, the highest PCE of 16.69% with an outstanding shortcircuit current density of 26.96 mA·cm^(-2) was obtained, which are one of the highest values for siloxane-functionalized polymer-based devices.This work demonstrates that finely controlling the content of siloxane-functionalized thiophene is beneficial for obtaining high-performance terpolymer donors and provides a novel and low-cost method to improve photovoltaic performance.展开更多
Tetrasubstituted olefins are significant scaffolds as they are prevalent in many biologically active compounds and versatile building blocks for organic synthesis. Herein, we report an electrochemical oxidative Csp^3...Tetrasubstituted olefins are significant scaffolds as they are prevalent in many biologically active compounds and versatile building blocks for organic synthesis. Herein, we report an electrochemical oxidative Csp^3—H/S—H cross-coupling reaction, in which various tetrasubstituted olefins were prepared under base-free, transition metal-free, and oxidants-free reaction conditions.展开更多
Since tetrasubstituted olefins serve as the key structure motifs in a large number of biologically active compounds,methods for synthesis of tetrasubstituted olefins are highly desirable.Among various synthetic method...Since tetrasubstituted olefins serve as the key structure motifs in a large number of biologically active compounds,methods for synthesis of tetrasubstituted olefins are highly desirable.Among various synthetic methodologies,the most known strategies are the functionalization of olefins,alkynes,and allenes.For example,Zhang,Gosselin and co-workers prepared a series of tetrasubstituted olefins via Suzuki-Miyaura coupling (Scheme 1a).[1] Morandi and co-workers reported a palladium-catalyzed intermolecular aryliodination of internal alkynes (Scheme 1b).[2] Ma and co-workers prepared a series of tetrasubstituted olefins by using readily available organozinc reagents and 2,3-allenals (Scheme 1c).[3] Despite extensive advances,the reported methods often require pre-prepared starting materials,inevitably leading to some by-products.Recently,under the supervision of Prof.Wang and Lei,we and Yang et al.reported an unprecedented electrochemical oxidative Csp3-H/S-H cross-coupling reaction between thiophenols and acetonitrile (Scheme 1d),yielding a series of tetrasubstituted olefins under exogenous-oxidant-free conditions.展开更多
The synthesis of carbazoles based on the electrochemical Pd-catalyzed intramolecular C-H amination of 2-amidobiaryls through oxidative cross coupling has been achieved under mild reaction conditions.The reaction can b...The synthesis of carbazoles based on the electrochemical Pd-catalyzed intramolecular C-H amination of 2-amidobiaryls through oxidative cross coupling has been achieved under mild reaction conditions.The reaction can be carried out in undivided cell without the addition of external chemical oxidant.Besides good functional group compatibility,the desired carbazoles can be scaled up and modified easily.Compared with previous methods,this protocol affords a simple and sustainable avenue for the construction of car-bazoles.展开更多
Non-fused ring electron acceptors(NFREAs)have a broad application prospect in the commercialization of organic solar cells(OSCs)due to the advantages of simple synthesis and low cost.The selection of intermediate bloc...Non-fused ring electron acceptors(NFREAs)have a broad application prospect in the commercialization of organic solar cells(OSCs)due to the advantages of simple synthesis and low cost.The selection of intermediate block cores of non-fused frameworks and the establishment of the relationship between molecular structure and device performance are crucial for the realization of high-performance OSCs.Herein,two A-D-A’-D-A type NFREAs namely CBTBO-4F and CBTBO-4Cl,constructed with a novel electron-deficient block unit N-(2-butyloctyl)-carbazole[3,4-c:5,6-c]bis[1,2,5]thiadiazole(CBT)and bridging unit 4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b’]dithiophene(DTC)coupling with different terminals(IC-2F/2Cl),were designed and synthesized.The two NFREAs feature broad and strong photoresponse from 500 nm to 900 nm due to the strong intramolecular charge transfer characteristics.Compared with CBTBO-4F,CBTBO-4Cl shows better molecular planarity,stronger crystallinity,more ordered molecular stacking,larger van der Waals surface,lower energy level and better active layer morphology,contributing to much better charge separation and transport behaviors in its based devices.As a result,the CBTBO-4Cl based device obtains a higher power conversion efficiency of 10.18%with an open-circuit voltage of 0.80 V and a short-circuit current density of 21.20 mA/cm^(2).These results not only demonstrate the great potential of CBT,a new building block of the benzothiazole family,in the construction of high-performance organic conjugated semiconductors,but also suggest that the terminal chlorination is an effective strategy to improve device performance.展开更多
In recent years,perovskite solar cells(PSCs)have gone through unparalleled rapid expansion and become a candidate for solar cells.Among various PSCs,though typical three-dimensional(3D)halide perovskite-based PSCs del...In recent years,perovskite solar cells(PSCs)have gone through unparalleled rapid expansion and become a candidate for solar cells.Among various PSCs,though typical three-dimensional(3D)halide perovskite-based PSCs deliver the highest efficiency,they are subjected to severe instability,which constrains their commercializability.In comparison,two-dimensional(2D)PSCs have aroused widespread concern due to their superior stability.After that,2D/3D perovskite materials combining high efficiency and good stability have emerged as the times require,which are expected to bring about stable and efficient PSCs.Here,this review focuses on selection of functional spacer cations for efficient and stable 2D/3D PSCs.First,the unique function of different spacer groups and the selection of appropriate spacer cations in 2D perovskites is summarized and proposed.Then,by selecting appropriate cations,the role of 2D perovskites is elaborated,including energy level regulation,ion migration suppression,defect passivation,residual stress release and improved stability.In addition,the preparation methods of 2D/3D perovskites are comprehensively summarized.Finally,current challenges and future opportunities for the further development of 2D/3D perovskites for solar cells are discussed and prospected.展开更多
A stable and commercially available reagent mixture,composed of tetrabutylammonium bifluoride/potassium bifluoride(TBAF/KHF_2),was found to be effective for the nucleophilic ring opening reactions of sugar-derived e...A stable and commercially available reagent mixture,composed of tetrabutylammonium bifluoride/potassium bifluoride(TBAF/KHF_2),was found to be effective for the nucleophilic ring opening reactions of sugar-derived epoxides with fluoride.Different sugar-derived epoxide precursors,including 1-thioglycosides can be ring-opened to afford fluorinated carbohydrate products in high yields and in short reaction times.展开更多
Triboelectric nanogenerators(TENGs)based on conjunctive effects of contact electrification(CE)and electrostatic induction are emerging as a new mechanical energy harvesting and sensing technique for promising applicat...Triboelectric nanogenerators(TENGs)based on conjunctive effects of contact electrification(CE)and electrostatic induction are emerging as a new mechanical energy harvesting and sensing technique for promising applications in smart wearables,Internet of Things(IoTs),etc.The surface microstructure of a flexible triboelectric material for the increase of surface area is a common strategy for performance enhancement of TENGs,but the real roles of surface microstructures on their output performance are still not explicit due to the lack of suitable analysis tool and rational experimental design.Taking advantages of the surface-sensitive characteristic of CE effect,this work exploited and developed the electric signal patterns generated by single impact of TENGs as a kind of CE spectrum to analyze and speculate the real roles of surface microstructures of flexible triboelectric materials on the output performance of TENGs.Firstly,four different kinds of surface microstructures,namely planar surface(PS)and three combinations of two basic surface microstructures,i.e.,micro lens arrays(MLAs),fabric textures(FTs),and hierarchical structures of MLAs on FTs(MLA/FTs),were elaborately designed and introduced for an identical triboelectric material(i.e.,silicone elastomer)by a(micro)molding synthesis route.Then they were used for assembly of TENGs based on vertical contact mode to conduct performance evaluation under the same triggering conditions.Through systematic analysis and comparison of their highly repeatable CE spectra by programmed machine,it was found that the surface microstructure for a flexible triboelectric material to maximally enhance the output performance of a TENG shall achieve a positive synergistic effect of increasing triboelectric charge density,effective contact area and contacting/separating velocity,rather than simple increase of its surface area.展开更多
Blending of poly(levorotatory-lactic acid) (PLLA) and poly(dextrorotatory-lactic acid) (PDLA) produces the stereocomplex crystallites (PLA SC), which present higher melting temperature and mechanical properties than t...Blending of poly(levorotatory-lactic acid) (PLLA) and poly(dextrorotatory-lactic acid) (PDLA) produces the stereocomplex crystallites (PLA SC), which present higher melting temperature and mechanical properties than that of neat PLLA or PDLA. However, in the PLLA/PDLA blends with higher molecular weights, the phase separation occurs and the SC exhibits weak memory after melting, which lead to a small amount of SC together with a large amount of homochiral crystallites (HC) develop during crystallization from the melt. In this study, a small content of graphite oxide was blended with PLLA and PDLA to form ternary blends, and it was exciting to find that the formation of SC was enhanced gradually with the content of graphite oxide. The SC exclusively developed when 2 wt% graphite oxide was incorporated into the PLLA/PDLA, and the crystallinity with ∼50% was received even during fast cooling from the melt (−50 ℃/min). The acceleration formation of SC was speculated due to the interaction between PLA molecular chains and the hydroxyl groups on the surface of graphite oxide and the obstruction of proliferation of graphite oxide.展开更多
The inevitable ion migration that occurs within ionic polycrystalline perovskite film results in inferior longterm stability of perovskite solar cells(PVSCs)that cannot meet the commercial requirements.Here,a novel po...The inevitable ion migration that occurs within ionic polycrystalline perovskite film results in inferior longterm stability of perovskite solar cells(PVSCs)that cannot meet the commercial requirements.Here,a novel poly(ionic liquid)named poly-1-vinyl-3-propyltrimethoxysilane imidazolium chloride(PImIL-SiO)is first introduced into perovskite to strengthen grain boundaries(GBs)and construct dual-functional barriers against internal ion migration and external moisture erosion for fabricating highly efficient and stable PVSCs.PImIL-SiO-containing imidazoliumcations and pendant siloxane groups contribute to passivation of bulk defects and anchoring of GBs,which effectively hinders ion migration channels,thus reducing perovskite film phase separation and device hysteresis.Furthermore,the intrinsically hydrophobic PImIL-SiO automatically forms a secondary protective barrier to endow the perovskite film with ultrahigh moisture corrosion resistance through the hydrolyzation reaction of siloxane with the permeated moisture.Consequently,the PImIL-SiO-modified PVSCs achieve a champion power conversion efficiency(PCE)of 22.46%,accompaniedby excellent thermal andhumidity stabilities where the non-encapsulated devices retain 87%of the initial PCE after aging at 85℃for 250 h and>85%of the initial PCE over 1100 h in air with a relative humidity of 50–70%.展开更多
Passivating the interfacial defects and reducing the interfacial non-radiative recombination losses are the keys to improving the photovoltaic performance of three-dimensional(3D)perovskite solar cells(PVSCs).Stacking...Passivating the interfacial defects and reducing the interfacial non-radiative recombination losses are the keys to improving the photovoltaic performance of three-dimensional(3D)perovskite solar cells(PVSCs).Stacking two dimensional(2D)perovskites on 3D perovskite is a promising method for interfacial treatment that improves the stability and efficiency of PVSCs.Herein,we developed conjugated fluorinated benzimidazolium cation(FBIm+)which can be inserted between 3D perovskite and holetransporting layer(HTL)to form 2D perovskite in situ.The 2D single crystal structures of(FBIm)_(2)Pb I4and(FBIm)_(2)Pb Br_(4)were achieved and confirmed by single-crystal X-ray diffraction(XRD),while few single crystals of 2D perovskite based on imidazolium or benzimidazolium anchors have been reported.The 2D perovskite can passivate the interfacial defects,induce better crystallinity and orientation,conduct lower trap density and extend carrier lifetime.Furthermore,the energy level arrangement can be regulated by changing the counterion from iodide to bromide,which can efficiently improve the hole extraction and device performances.As a consequence,the best efficiency of 23.00%for FBIm Br-incorporated devices was achieved,while only 20.72%for the control device.Meanwhile,the PVSCs modified by FBIm Br displayed excellent environmental stability due to the constructed hydrophobic 2D perovskite layer which can effectively block moisture permeation.This work develops a new path to design novel conjugated organic passivants to form 2D/3D perovskite structures.展开更多
Despite their excellent environmental stability,low defect density,and high carrier mobility,large-n quasi-two-dimensional halide perovskites(quasi-2DHPs)feature a limited application scope because of the formation of...Despite their excellent environmental stability,low defect density,and high carrier mobility,large-n quasi-two-dimensional halide perovskites(quasi-2DHPs)feature a limited application scope because of the formation of self-assembled multiple quantum wells(QWs)due to the similar thermal stabilities of large-n phases.However,large-n quasi-phase-pure 2DHPs(quasi-PP-2DHPs)can solve this problem perfectly.This review discusses the structures,formation mechanisms,and photoelectronic and physical properties of quasi-PP-2DHPs,summarises the corresponding single crystals,thin films,and heterojunction preparation methods,and presents the related advances.Moreover,we focus on applications of large-n quasi-PP-2DHPs in solar cells,photodetectors,lasers,light-emitting diodes,and field-effect transistors,discuss the challenges and prospects of these emerging photoelectronic materials,and review the potential technological developments in this area.展开更多
Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film ...Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film thickness,which is inserted between active components and stable silver electrode to align work function,and maintain good interfacial contact and device stability.The thick film can help to reduce interfacial surface defects,keep stable surface morphology,and block the silver diffusion into the active layer.Consequently,the optimal PM6:Y6 device records an impressive power conversion efficiency(PCE)of 17.48%with minimized non-radiative recombination loss of 0.239 V.More importantly,the unencapsulated device maintains 91%of the original PCE after aging for over 60 days at 25℃ and 10%relative humidity in dark conditions.Meanwhile,the PM6:eC9 device achieves a remarkable PCE of 18.22%with the enhancement of open-circuit voltage(V_(oc)).Furthermore,the 1 cm^(2) device-based PDINO(15 nm)/Ag shows a high PCE of 15.2%while only 12.6%for PDINO(9 nm)/Al,indicating the good compatibility of PDINO(15 nm)interlayer with the R2R coating processes used in large-area OPVs fabrication.This work highlights the promise of interfacial regulation to simultaneously stabilize and enhance the efficiency of organic photovoltaics.展开更多
基金financially supported by the Open Fund of Energy and Materials Chemistry Joint Laboratory of SCNU and TINCI,China (SCNU-TINCI-202207)。
文摘Solving the problems of low electrical conductivity and poor cycling durability in transition metal oxidesbased anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has already turned into an urgent requirement.In this paper,we successfully synthesized Co_(2)VO_(4)/Co compounds with Co-VMOF(metal-organic framework)as a sacrificial template and investigated their electrochemical mechanism in order to improve the electrochemical properties of LIBs and SIBs.The optimized heaping configuration and the existence of metallic Co catalyzed the formation of radical ions,thereby facilitating higher conductivity,shortening Li+and Na+transport paths,and providing more active sites.Co_(2)VO_(4)/Co constructed with 2-methylimidazole as a ligand showed a discharge capacity of 1605.1 mA h g^(-1)after 300 cycles at 0.1 A g^(-1)in LIB and 677.2 mA h g^(-1)in SIB.Density functional theory(DFT)calculation emphasizes the crucial role of Co_(2)VO_(4)/Co in enhancing electrode conductivity,decreasing the migratory energy barrier,and thereby strengthening electrochemical properties.This heterostructure building technique may pave the way for the development of high-performance LIBs and SIBs.Furthermore,the problem of the low first-loop coulombic efficiency faced by transition metal oxides is improved.
基金support from the National Natural Science Foundation of China(NSFC)(52163019,22005131,52173169 and U20A20128)support from the Natural Science Foundation of Jiangxi Province(20224ACB214006)。
文摘Although two-dimensional perovskite devices are highly stable,they also lead to a number of challenges.For instance,the introduction of large organic amines makes crystallization process complicated,causing problems such as generally small grain size and blocked charge transfer.In this work,imprint assisted with methylamine acetate were used to improve the morphology of the film,optimize the internal phase distribution,and enhance the charge transfer of the perovskite film.Specifically,imprint promoted the dispersion of spacer cations in the recrystallization process with the assistance of methylamine acetate,thus inhibited the formation of low-n phase induced by the aggregation of spacer cations and facilitated the formation of 3D-like phase.In this case,the corresponding quasi-2D perovskite solar cells delivered improved efficiency and exhibited superior stability.Our work provides an effective strategy to obtain uniform phase distribution for quasi-2D perovskite.
基金National Natural Science Foundation of China,Grant/Award Number:22162014 and 22162013Natural Science Foundation of Jiangxi Province of China,Grant/Award Number:20212ACB204009+1 种基金Sponsored Program for Academic and Technical Leaders of Major Disciplines of Jiangxi Province of China,Grant/Award Number:20212BCJL23059Doctoral Research Foundation Project of Tongren University,Grant/Award Number:trxyDH2204。
文摘The rational synthesis of a two-dimensional(2D)porous aromatic framework(PAF)with a controllable growth direction remains a challenge to overcome the limitation of traditional stacked 2D materials.Herein,a step-growth strategy is developed to fabricate a vertically oriented nitrogen-rich porous aromatic framework on graphene oxide(V-PAF-GO)using monolayer benzidine-functionalized GO(BZ-GO)as a molecular pillar.Then,the confined Co nanoparticle(NP)catalysts are synthesized by encapsulating ultra-small Co into the slit pores of V-PAF-GO.Due to the high nitrogen content,large specific surface area,and adequate slit pores,the optimized vertical nanocomposites V-PAF-GO provide abundant anchoring sites for metal NPs,leading to ultrafine Co NPs(1.4 nm).The resultant Co/V-PAF-GO catalyst shows an extraordinary catalytic activity for ammonia borane(AB)methanolysis,yielding a turnover frequency value of 47.6 min−1 at 25°C,comparable to the most effective non-noble-metal catalysts ever reported for AB methanolysis.Experimental and density functional theory studies demonstrate that the electron-donating effect of N species of PAF positively corresponds to the low barrier in methanol molecule activation,and the cleavage of the O–H bond in CH3OH has been proven to be the rate-determining step for AB methanolysis.This work presents a versatile step-growth strategy to prepare a vertically oriented PAF on GO to solve the stacking problem of 2D materials,which will be used to fabricate other novel 2D or 2D–2D materials with controllable orientation for various 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 financial support from the Research and Development Plan Project in Key Fields of Guangdong Province(2020B0101030005)Applied Special Project of Guangdong Provincial Science and Technology Plan(2017B090917002)+1 种基金Basic and Applied Basic Research Fund of Guangdong Province(2019B1515120027)Key R&D projects in Guangdong Province(2020B0101030005)。
文摘LiFePO_(4),as a prevailing cathode material for lithium-ion batteries(LIBs),still encounters issues such as intrinsic poor electronic conductivity,inferior Li-ion diffusion kinetic,and two-phase transformation mechanism involving substantial structural rearrangements,resulting in unsatisfactory rate performance.Carbon coating,cation doping,and morphological control have been widely employed to reconcile these issues.Inspired by these,we propose a synthetic route with metal–organic frameworks(MOFs)as self-sacrificial templates to simultaneously realize shape modulation,Mn doping,and N-doped carbon coating for enhanced electrochemical performances.The as-synthesized Li MnxFe1–xPO4/C(x=0,0.25,and0.5)deliver tunable electrochemical behaviors induced by the MOF templates,among which LiMn_(0.25)Fe_(0.75)PO_(4)/C outperforms its counterparts in cyclability(164.7 mA h g^(-1)after 200 cycles at 0.5 C)and rate capability(116.3 mA h g^(-1)at 10 C).Meanwhile,the ex-situ XRD reveals a dominant single-phase solid solution mechanism of LiMn_(0.25)Fe_(0.75)PO_(4)/C during delithiation,contrary to the pristine LiFePO_(4),without major structural reconstruction,which helps to explain the superior rate performance.Furthermore,the density functional theory(DFT)calculations verify the effects of Mn doping and embody the superiority of LiMn_(0.25)Fe_(0.75)PO_(4)/C as a LIB cathode,which well supports the experimental observations.This work provides insightful guidance for the design of tunable MOF-derived mixed transitionmetal systems for advanced LIBs.
基金the financial support from the Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(“Climbing Program”Special Funds,pdjh2023b0145)the Research and Development Plan Project in Key Fields of Guangdong Province(2020B0101030005)+1 种基金the Applied special project of Guangdong Provincial Science and Technology Plan(2017B090917002)the Basic and Applied Basic Research Fund of Guangdong Province(2019B1515120027)。
文摘Despite the dazzling theoretical capacity,the devasting electrochemical activity of Li_(2)MnO_(3)(LMO)caused by the difficult oxidation of Mn4+impedes its practical application as the lithium-ion battery(LIB)cathode.The efficacious activation of the Li_(2)MnO_(3) by importing electrochemically active Mn3+ions or morphological engineering is instrumental to its lithium storage activity and structural integrity upon cycling.Herein,we propose a conceptual strategy with metal-organic frameworks(MOFs)as self-sacrificial templates to prepare oxygen-deficient Li_(2)MnO_(3)(O_v-LMO)for exalted lithium storage performance.Attributed to optimized morphological features,LMO materials derived from Mn-BDC(H_(2)BDC=1,4-dicarboxybenzene)delivered superior cycling/rate performances compared with their counterparts derived from Mn-BTC(H_(3)BTC=1,3,5-benzenetricarboxylicacid)and Mn-PTC(H_(4)PTC=pyromellitic acid).Both experimental and theoretical studies elucidate the efficacious activation of primitive LMO materials toward advanced lithium storage by importing oxygen deficiencies.Impressively,O_v-LMO derived from Mn-BDC(O_v-BDC-LMO)delivered intriguing reversible capacities(179.2 mA h g^(-1)at 20 mA g^(-1)after 200 cycles and 100.1 mA h g^(-1)at 80 mA g^(-1)after 300 cycles),which can be attributed to the small particle size that shortens pathways for Li+/electron transport,the enhanced redox activity induced by abundant oxygen vacancies,and the optimized electronic configuration that contributes to the faster lithium diffusivity.This work provides insights into the rational design of LMO by morphological and atomic modulation to direct its activation and practical application as an advanced LIB cathode.
基金supported by the National Natural Science Foundation of China(Nos.51403089 and 21574060)the Major Special Projects of Jiangxi Provincial Department of Science and Technology(No.20114ABF05100)+3 种基金the Project of Jiangxi Provincial Department of Education(No.GJJ170229)the China Postdoctoral Science Foundation(No.2019M652282)the Postdoctoral Science Foundation of Jiangxi Province(No.2018KY37)the Technology Plan Landing Project of Jiangxi Provincial Department of Education(No.GCJ2011-243).
文摘For a polymer/polymer dismissible blend with two crystallizable components,the crystallization behavior of different components and the reciprocal influences between different crystals are interesting and important,but did not investigate in detail.In this study,the L-poly(lactic acid)/polypropylene(PLLA/PP)blends with different weight ratios were prepared by melt mixing and the crystallization behavior of the blends were investigated.Results showed that the crystalline structures of PLLA and PP were not altered by the composition.For the crystallization of PLLA,both the diffusion of chain segments and crystallization rate were enhanced under the existence of PP crystals.For the crystallization of PP,its crystallization rate was depressed under the existence of amorphous PLLA molecular chains.When the PP crystallized from the existence of PLLA crystals,although the diffusion rate of PP was reduced by PLLA crystals,the nucleation positions were obviously enhanced,which accelerated the formation of PP crystals.This investigation would supply more basic data for the application of PLLA/PP blend.
基金financially supported by the National Natural Science Foundation of China (NSFC) (Nos.51973032,21905043,51833004 and 52333006)the Jiangxi Provincial Natural Science Foundation (Nos.20212ACB203005,20224ACB214002,20212BAB213018 and 20224BAB203015)+2 种基金the Thousand Talents Plan of Jiangxi Province (No.jxsq2019101051)the Innovation Foundation for graduate students of Jiangxi Normal University (No.YJS2021018)the financial support from Research Grants Council (RGC) of Hong Kong (General Research Fund No.14303519)。
文摘Incorporation of siloxane-functionalized units into polymers backbone has proven to be an efficient strategy to improve photovoltaic performance. In this work, a low-cost siloxane-containing unit was developed to construct a series of terpolymers, and the effects of siloxane on the polymer performance were systematically studied. Different contents of thiophene containing siloxane-functionalized side chain were introduced into PM6 to obtain a series of polymers(PM6, PM6-SiO-10, PM6-SiO-20 and PM6-SiO-30). The siloxane-functionalized side chains in polymers have only a slight effect on the absorption behavior and frontier molecular orbitals. However, when the siloxane content increased, the terpolymers' aggregation property decreased and the temperature-dependency increased, leading to improved donor-acceptor compatibility. The power conversion efficiency(PCE) based on PM6:Y6, PM6-SiO-20:Y6 and PM6-SiO-30:Y6 devices was 15.64%, 16.03% and 15.82%, respectively. In comparison, the active layer based on PM6-SiO-10:Y6 exhibits the most appropriate phase separation morphology, resulting in effective exciton dissociation, more balanced hole-electron transport and less recombination. Consequently, the highest PCE of 16.69% with an outstanding shortcircuit current density of 26.96 mA·cm^(-2) was obtained, which are one of the highest values for siloxane-functionalized polymer-based devices.This work demonstrates that finely controlling the content of siloxane-functionalized thiophene is beneficial for obtaining high-performance terpolymer donors and provides a novel and low-cost method to improve photovoltaic performance.
基金the National Natural Science Foundation of China (Nos.21562026,21762025,21702027)the Natural Science Foundation of Jiangxi Province (No.20161BAB203085) for financial support.
文摘Tetrasubstituted olefins are significant scaffolds as they are prevalent in many biologically active compounds and versatile building blocks for organic synthesis. Herein, we report an electrochemical oxidative Csp^3—H/S—H cross-coupling reaction, in which various tetrasubstituted olefins were prepared under base-free, transition metal-free, and oxidants-free reaction conditions.
文摘Since tetrasubstituted olefins serve as the key structure motifs in a large number of biologically active compounds,methods for synthesis of tetrasubstituted olefins are highly desirable.Among various synthetic methodologies,the most known strategies are the functionalization of olefins,alkynes,and allenes.For example,Zhang,Gosselin and co-workers prepared a series of tetrasubstituted olefins via Suzuki-Miyaura coupling (Scheme 1a).[1] Morandi and co-workers reported a palladium-catalyzed intermolecular aryliodination of internal alkynes (Scheme 1b).[2] Ma and co-workers prepared a series of tetrasubstituted olefins by using readily available organozinc reagents and 2,3-allenals (Scheme 1c).[3] Despite extensive advances,the reported methods often require pre-prepared starting materials,inevitably leading to some by-products.Recently,under the supervision of Prof.Wang and Lei,we and Yang et al.reported an unprecedented electrochemical oxidative Csp3-H/S-H cross-coupling reaction between thiophenols and acetonitrile (Scheme 1d),yielding a series of tetrasubstituted olefins under exogenous-oxidant-free conditions.
基金This work was supported by the National Natural Science Foundation of China(No.21520102003)the Hubei Province Natural Science Foundation of China(No.2017CFA010).The Program of Introducing Talents of Discipline to Universities of China(111 Program)is also appreciated.
文摘The synthesis of carbazoles based on the electrochemical Pd-catalyzed intramolecular C-H amination of 2-amidobiaryls through oxidative cross coupling has been achieved under mild reaction conditions.The reaction can be carried out in undivided cell without the addition of external chemical oxidant.Besides good functional group compatibility,the desired carbazoles can be scaled up and modified easily.Compared with previous methods,this protocol affords a simple and sustainable avenue for the construction of car-bazoles.
基金This work was financially supported by the National Natural Science Foundation of China(NSFC,Nos.51973032,21905043 and 51833004)the“Chenguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.19CG36)+4 种基金the Jiangxi Provincial Natural Science Foundation(Nos.20212ACB203005 and 20212BAB213018)the Thousand Talents Plan of Jiangxi Province(No.jxsq2019101051)the Jiangxi Provincial Education Department Science and Technology Research Foundation(No.GJJ210310)X.Xia and X.Lu acknowledge the financial support from Research Grants Council(RGC)of Hong Kong(General Research Fund No.14303519)Y.Chen expresses thanks for the support from the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(No.CUSF-DH-D-2021008).
文摘Non-fused ring electron acceptors(NFREAs)have a broad application prospect in the commercialization of organic solar cells(OSCs)due to the advantages of simple synthesis and low cost.The selection of intermediate block cores of non-fused frameworks and the establishment of the relationship between molecular structure and device performance are crucial for the realization of high-performance OSCs.Herein,two A-D-A’-D-A type NFREAs namely CBTBO-4F and CBTBO-4Cl,constructed with a novel electron-deficient block unit N-(2-butyloctyl)-carbazole[3,4-c:5,6-c]bis[1,2,5]thiadiazole(CBT)and bridging unit 4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b’]dithiophene(DTC)coupling with different terminals(IC-2F/2Cl),were designed and synthesized.The two NFREAs feature broad and strong photoresponse from 500 nm to 900 nm due to the strong intramolecular charge transfer characteristics.Compared with CBTBO-4F,CBTBO-4Cl shows better molecular planarity,stronger crystallinity,more ordered molecular stacking,larger van der Waals surface,lower energy level and better active layer morphology,contributing to much better charge separation and transport behaviors in its based devices.As a result,the CBTBO-4Cl based device obtains a higher power conversion efficiency of 10.18%with an open-circuit voltage of 0.80 V and a short-circuit current density of 21.20 mA/cm^(2).These results not only demonstrate the great potential of CBT,a new building block of the benzothiazole family,in the construction of high-performance organic conjugated semiconductors,but also suggest that the terminal chlorination is an effective strategy to improve device performance.
基金support from the National Natural Science Foundation of China(NSFC)(grant nos.52163019,22005131,52173169,and U20A20128)support from the China Postdoctoral Science Foundation(grant no.2021M700060)the Postdoctoral Innovative Talents Support Program(grant no.BX2021117).
文摘In recent years,perovskite solar cells(PSCs)have gone through unparalleled rapid expansion and become a candidate for solar cells.Among various PSCs,though typical three-dimensional(3D)halide perovskite-based PSCs deliver the highest efficiency,they are subjected to severe instability,which constrains their commercializability.In comparison,two-dimensional(2D)PSCs have aroused widespread concern due to their superior stability.After that,2D/3D perovskite materials combining high efficiency and good stability have emerged as the times require,which are expected to bring about stable and efficient PSCs.Here,this review focuses on selection of functional spacer cations for efficient and stable 2D/3D PSCs.First,the unique function of different spacer groups and the selection of appropriate spacer cations in 2D perovskites is summarized and proposed.Then,by selecting appropriate cations,the role of 2D perovskites is elaborated,including energy level regulation,ion migration suppression,defect passivation,residual stress release and improved stability.In addition,the preparation methods of 2D/3D perovskites are comprehensively summarized.Finally,current challenges and future opportunities for the further development of 2D/3D perovskites for solar cells are discussed and prospected.
基金the National Natural Science Foundation of China (No. 21502076) for the financial support
文摘A stable and commercially available reagent mixture,composed of tetrabutylammonium bifluoride/potassium bifluoride(TBAF/KHF_2),was found to be effective for the nucleophilic ring opening reactions of sugar-derived epoxides with fluoride.Different sugar-derived epoxide precursors,including 1-thioglycosides can be ring-opened to afford fluorinated carbohydrate products in high yields and in short reaction times.
基金supported by the National Natural Science Foundation of China(No.52103278).
文摘Triboelectric nanogenerators(TENGs)based on conjunctive effects of contact electrification(CE)and electrostatic induction are emerging as a new mechanical energy harvesting and sensing technique for promising applications in smart wearables,Internet of Things(IoTs),etc.The surface microstructure of a flexible triboelectric material for the increase of surface area is a common strategy for performance enhancement of TENGs,but the real roles of surface microstructures on their output performance are still not explicit due to the lack of suitable analysis tool and rational experimental design.Taking advantages of the surface-sensitive characteristic of CE effect,this work exploited and developed the electric signal patterns generated by single impact of TENGs as a kind of CE spectrum to analyze and speculate the real roles of surface microstructures of flexible triboelectric materials on the output performance of TENGs.Firstly,four different kinds of surface microstructures,namely planar surface(PS)and three combinations of two basic surface microstructures,i.e.,micro lens arrays(MLAs),fabric textures(FTs),and hierarchical structures of MLAs on FTs(MLA/FTs),were elaborately designed and introduced for an identical triboelectric material(i.e.,silicone elastomer)by a(micro)molding synthesis route.Then they were used for assembly of TENGs based on vertical contact mode to conduct performance evaluation under the same triggering conditions.Through systematic analysis and comparison of their highly repeatable CE spectra by programmed machine,it was found that the surface microstructure for a flexible triboelectric material to maximally enhance the output performance of a TENG shall achieve a positive synergistic effect of increasing triboelectric charge density,effective contact area and contacting/separating velocity,rather than simple increase of its surface area.
基金financially supported by the National Natural Science Foundation of China (Nos. 51403089 and 21574060)the Major Special Projects of Jiangxi Provincial Department of Science and Technology (No. 20114ABF05100)+5 种基金the Project of Jiangxi Provincial Department of Education (No. GJJ170229)the China Postdoctoral Science Foundation (No. 2019M652282)the Postdoctoral Science Foundation of Jiangxi Province (No. 2018KY37)the Technology Plan Landing Project of Jiangxi Provincial Department of Education (No. GCJ2011-243)the Science Foundation for Excellent Young Scholars of Jiangxi Province (No. 20202ZDB01003)the Science foundation of Jiangxi Province (No. 20202BAB203008)
文摘Blending of poly(levorotatory-lactic acid) (PLLA) and poly(dextrorotatory-lactic acid) (PDLA) produces the stereocomplex crystallites (PLA SC), which present higher melting temperature and mechanical properties than that of neat PLLA or PDLA. However, in the PLLA/PDLA blends with higher molecular weights, the phase separation occurs and the SC exhibits weak memory after melting, which lead to a small amount of SC together with a large amount of homochiral crystallites (HC) develop during crystallization from the melt. In this study, a small content of graphite oxide was blended with PLLA and PDLA to form ternary blends, and it was exciting to find that the formation of SC was enhanced gradually with the content of graphite oxide. The SC exclusively developed when 2 wt% graphite oxide was incorporated into the PLLA/PDLA, and the crystallinity with ∼50% was received even during fast cooling from the melt (−50 ℃/min). The acceleration formation of SC was speculated due to the interaction between PLA molecular chains and the hydroxyl groups on the surface of graphite oxide and the obstruction of proliferation of graphite oxide.
基金supported by National Natural Science Foundation of China(NSFC)(grant nos.52063019,51973088,51833004,U20A20128).
文摘The inevitable ion migration that occurs within ionic polycrystalline perovskite film results in inferior longterm stability of perovskite solar cells(PVSCs)that cannot meet the commercial requirements.Here,a novel poly(ionic liquid)named poly-1-vinyl-3-propyltrimethoxysilane imidazolium chloride(PImIL-SiO)is first introduced into perovskite to strengthen grain boundaries(GBs)and construct dual-functional barriers against internal ion migration and external moisture erosion for fabricating highly efficient and stable PVSCs.PImIL-SiO-containing imidazoliumcations and pendant siloxane groups contribute to passivation of bulk defects and anchoring of GBs,which effectively hinders ion migration channels,thus reducing perovskite film phase separation and device hysteresis.Furthermore,the intrinsically hydrophobic PImIL-SiO automatically forms a secondary protective barrier to endow the perovskite film with ultrahigh moisture corrosion resistance through the hydrolyzation reaction of siloxane with the permeated moisture.Consequently,the PImIL-SiO-modified PVSCs achieve a champion power conversion efficiency(PCE)of 22.46%,accompaniedby excellent thermal andhumidity stabilities where the non-encapsulated devices retain 87%of the initial PCE after aging at 85℃for 250 h and>85%of the initial PCE over 1100 h in air with a relative humidity of 50–70%.
基金supported by the National Natural Science Foundation of China(51763013)the Natural Science Foundation of Jiangxi Province(20224ACB213002)the Foundation of Jiangxi Educational Committee(GJJ200301)。
文摘Passivating the interfacial defects and reducing the interfacial non-radiative recombination losses are the keys to improving the photovoltaic performance of three-dimensional(3D)perovskite solar cells(PVSCs).Stacking two dimensional(2D)perovskites on 3D perovskite is a promising method for interfacial treatment that improves the stability and efficiency of PVSCs.Herein,we developed conjugated fluorinated benzimidazolium cation(FBIm+)which can be inserted between 3D perovskite and holetransporting layer(HTL)to form 2D perovskite in situ.The 2D single crystal structures of(FBIm)_(2)Pb I4and(FBIm)_(2)Pb Br_(4)were achieved and confirmed by single-crystal X-ray diffraction(XRD),while few single crystals of 2D perovskite based on imidazolium or benzimidazolium anchors have been reported.The 2D perovskite can passivate the interfacial defects,induce better crystallinity and orientation,conduct lower trap density and extend carrier lifetime.Furthermore,the energy level arrangement can be regulated by changing the counterion from iodide to bromide,which can efficiently improve the hole extraction and device performances.As a consequence,the best efficiency of 23.00%for FBIm Br-incorporated devices was achieved,while only 20.72%for the control device.Meanwhile,the PVSCs modified by FBIm Br displayed excellent environmental stability due to the constructed hydrophobic 2D perovskite layer which can effectively block moisture permeation.This work develops a new path to design novel conjugated organic passivants to form 2D/3D perovskite structures.
基金supported by the National Natural Science Foundation of China(62105292,61935017,and 62175268)Shaanxi Fundamental Science Research Project for Mathematics and Physics(22JSY015)+7 种基金Young Talent Fund of Xi’an Association for Science and Technology(959202313020)the Natural Science Foundation of Shaanxi Province(2021GXLH-Z-0 and 2020JZ-02)the Project of Innovative Team of Shaanxi Province(2020TD-001)the China Fundamental Research Funds for the Central Universitiesthe Science and Technology Development Fund,Macao SAR(FDCT-0044/2020/A1,006/2022/ALC)UM’s research fund(MYRG2022-00241-IAPME,MYRG-CRG2022-00009-FHS)the research fund from Wuyi University(EF38/IAPME-XGC/2022/WYU)Shenzhen-Hong Kong-Macao Science and Technology Innovation Project(Category C)(SGDX2020110309360100)。
文摘Despite their excellent environmental stability,low defect density,and high carrier mobility,large-n quasi-two-dimensional halide perovskites(quasi-2DHPs)feature a limited application scope because of the formation of self-assembled multiple quantum wells(QWs)due to the similar thermal stabilities of large-n phases.However,large-n quasi-phase-pure 2DHPs(quasi-PP-2DHPs)can solve this problem perfectly.This review discusses the structures,formation mechanisms,and photoelectronic and physical properties of quasi-PP-2DHPs,summarises the corresponding single crystals,thin films,and heterojunction preparation methods,and presents the related advances.Moreover,we focus on applications of large-n quasi-PP-2DHPs in solar cells,photodetectors,lasers,light-emitting diodes,and field-effect transistors,discuss the challenges and prospects of these emerging photoelectronic materials,and review the potential technological developments in this area.
基金supported by the National Natural Science Foundation of China(51903189,51800334)。
文摘Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film thickness,which is inserted between active components and stable silver electrode to align work function,and maintain good interfacial contact and device stability.The thick film can help to reduce interfacial surface defects,keep stable surface morphology,and block the silver diffusion into the active layer.Consequently,the optimal PM6:Y6 device records an impressive power conversion efficiency(PCE)of 17.48%with minimized non-radiative recombination loss of 0.239 V.More importantly,the unencapsulated device maintains 91%of the original PCE after aging for over 60 days at 25℃ and 10%relative humidity in dark conditions.Meanwhile,the PM6:eC9 device achieves a remarkable PCE of 18.22%with the enhancement of open-circuit voltage(V_(oc)).Furthermore,the 1 cm^(2) device-based PDINO(15 nm)/Ag shows a high PCE of 15.2%while only 12.6%for PDINO(9 nm)/Al,indicating the good compatibility of PDINO(15 nm)interlayer with the R2R coating processes used in large-area OPVs fabrication.This work highlights the promise of interfacial regulation to simultaneously stabilize and enhance the efficiency of organic photovoltaics.