Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stabi...Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stability.Two-dimensional(2D)Ruddlesden-Popper(RP)perovskites could address the aforementioned issue and present excellent stability because of their hydrophobic organic spacer cations.However,the crystallographic orientation of 2D crystals should be perpendicular to the bottom substrates for charges to transport fast and be collected in solar cells.Moreover,controlling the crystallographic orientation of the 2D RP perovskites prepared by the solution process is difficult.Herein,we reviewed the progress of recent research regarding 2D RP perovskite films with the focus on the crystallographic orientation mechanism and orientation controlling methods.Furthermore,the current issues and prospects of 2D RP perovskites in the photovoltaic field were discussed to elucidate their development and application in the future.展开更多
Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the supercondu...Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the superconductivity was only observed in La_(3)Ni_(2)O_(7)single crystal grown with the optical-image float-ing zone furnace under oxygen pressure.It remains to be understood the effect of chemical doping on superconducting La_(3)Ni_(2)O_(7)as well as other Ruddlesden-Popper phases.Here,we systematically investi-gate the effect of external pressure and chemical doping on polycrystalline Ruddlesden-Popper phases.Our results demonstrate that the application of pressure and doping effectively tunes the transport prop-erties of Ruddlesden-Popper phases.We find pressure-induced superconductivity up to 86 K in La_(3)Ni_(2)O_(7)polycrystalline sample,while no signatures of superconductivity are observed in La_(2)NiO_(4)and La_(4)Ni_(3)O_(10)polycrystalline samples under high pressure up to 50 GPa.Our study sheds light on the exploration of high-Tc superconductivity in nickelates.展开更多
Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of ...Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of bulky organic cation spacers limits the performance of 2DRP PSCs.Inspired by the Asite cation alloying strategy in 3D perovskites,2DRP perovskites with a binary spacer can promote charge transporting compared to the unary spacer counterparts.Herein,the superior MA-based 2DRP perovskite films with a binary spacer,including 3-guanidinopropanoic acid(GPA)and 4-fluorophenethylamine(FPEA)are realized.These films(GPA_(0.85)FPEA_(0.15))_(2)MA_(4)Pb_5I_(16)show good morphology,large grain size,decreased trap state density,and preferential orientation of the as-prepared film.Accordingly,the present 2DRP-based PSC with the binary spacer achieves a remarkable efficiency of 18.37%with a V_(OC)of1.15 V,a J_(SC)of 20.13 mA cm^(-2),and an FF of 79.23%.To our knowledge,the PCE value should be the highest for binary spacer MA-based 2DRP(n≤5)PSCs to date.Importantly,owing to the hydrophobic fluorine group of FPEA and the enhanced interlayer interaction by FPEA,the unencapsulated 2DRP PSCs based on binary spacers exhibit much excellent humidity stability and thermal stability than the unary spacer counterparts.展开更多
Development of high performance electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge for direct water splitting using an electrolyzer.Recently,Ruddlesden-Popper phase Sr_(2)IrO_(4)w...Development of high performance electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge for direct water splitting using an electrolyzer.Recently,Ruddlesden-Popper phase Sr_(2)IrO_(4)was discovered to be an efficient OER catalyst because of its unique structure,which consists of layers of both rock salt and perovskite phases simultaneously.In this study,we prepared a series of B-site mixed,Ruddlesden-Popper phase of Sr_(2)(Ru_(x)Ir_(1-x))O_(4) and examined their electrocatalytic properties for OER in acidic media.Through partial substitution of Ru in the B-site of Ruddlesden-Popper phase materials,we achieved much enhanced OER performance for this series of Sr_(2)(Ru_(x)Ir_(1-x))O_(4)electrocatalysts,among which Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)exhibited the best catalytic activity with a current density of 8.06 m A/cm^(2) at 1.55 V and a Tafel slope of 47 m V/dec.This current density is three times higher than that of Sr_(2)Ir O_(4).The B-site mixed Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)retained good stability in acidic conditions for>24 h at 10 m A/cm^(2).A range of techniques were used to characterize the crystal and electronic structures of the Sr_(2)(Ru_(x)Ir_(1-x))O_(4)samples.Our data indicate that the improved OER performance can be correlated to the formation of high level of hydroxyl groups and the enhanced overlap between Ir/Ru 4d and O_(2)p orbitals,revealing a new way for the design of efficient OER electrocatalysts by regulating their composition and electronic structures.展开更多
Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on a...Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on ammonium,whereas formamidinium(FA^(+))has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs.Herein,a novel FA-based organic spacer cation,4-chloro-phenylformamidinium(CPFA^(+)),is applied in quasi-2D Ruddlesden-Popper(RP)PSCs for the first time,and methylammonium chloride(MACl)is employed to promote crystal growth and orientation of perovskite film,resulting in high power conversion efficiency(PCE)with improved stability.Upon incorporating CPFA+organic spacer cation and MACl additive,high-quality quasi-2D CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)perovskite film forms,exhibiting improved crystal orientation,reduced trap state density,prolonged carrier lifetime and optimized energy level alignment.Consequently,the CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)quasi-2D RP PSC devices deliver a highest PCE of 14.78%.Moreover,the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain~80%of its original PCE after exceeding 2000 h storage under ambient condition,whereas the 3D MAPb I3counterparts retain only~45%of its original PCE.Thus,the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPb I3counterpart.展开更多
Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7...Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.展开更多
Ni-Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction(OER)in water electrolysis.However,understanding and mastering the synergy of Ni and Fe remain ch...Ni-Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction(OER)in water electrolysis.However,understanding and mastering the synergy of Ni and Fe remain challenging.Herein,we report that the synergy between Ni and Fe can be tailored by crystal dimensionality of Ni,Fe-contained Ruddlesden-Popper(RP)-type perovskites(La_(0.125)Sr_(0.875))n+1(Ni_(0.25)Fe_(0.75))nO3n+1(n=1,2,3),where the material with n=3 shows the best OER performance in alkaline media.Soft X-ray absorption spectroscopy spectra before and after OER reveal that the material with n=3 shows enhanced Ni/Fe-O covalency to boost the electron transfer as compared to those with n=1 and n=2.Further experimental investigations demonstrate that the Fe ion is the active site and the Ni ion is the stable site in this system,where such unique synergy reaches the optimum at n=3.Besides,as n increases,the proportion of unstable rock-salt layers accordingly decreases and the leaching of ions(especially Sr^(2+))into the electrolyte is suppressed,which induces a decrease in the leaching of active Fe ions,ultimately leading to enhanced stability.This work provides a new avenue for rational catalyst design through the dimensional strategy.展开更多
Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP micro...Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP microwires(RPP-MWs)and compared it with a 2D-RPP photodetector.The results show that the RPP-MWs photodetector possesses a wider photoresponse range and higher responsivities of 233 A/W in the visible band and 30 A/W in the near-infrared(NIR)band.The analyses show that the synthesized RPP-MWs have a multi-layer,heterogeneous core-shell structure.This structure gives RPP-MWs a unique band structure,as well as abundant trap states and defect levels,which enable them to acquire better photoresponse performance.This configuration of RPP-MWs provides a new idea for the design and application of novel heterostructures.展开更多
Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on...Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas;however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.To address this issue,triphenylphosphine is proposed to be a reduction promotor for accelerating the reduction and migration of the target metal atoms,aiming to achieve the effective exsolution of metallic species from Ruddlesden-Popper-type parent perovskites.Upon oxygen evolution reaction,these exsolved metallic aggregates are reconstructed into oxyhydroxides as the real active centers.After further modification by lowpercentage iridium oxide nanoclusters,the optimal catalyst delivered an overpotential as low as 305 mV for generating the density of 10 mA cm^(-2),outperforming these reported noble metal-containing perovskite-based alkaline oxygen evolution reaction electrocatalysts.This work provides a potential approach to activate catalytically inert oxides through promoting surface metal exsolution and explores a novel class of Ruddlesden-Poppertype oxides for electrocatalytic applications.展开更多
Ruddlesden-Popper(RP)layered perovskite single crystals(SCs)have been widely utilized in high-performance and weather-resistant photodetectors(PDs)due to their unique properties,including highly anisotropic carrier tr...Ruddlesden-Popper(RP)layered perovskite single crystals(SCs)have been widely utilized in high-performance and weather-resistant photodetectors(PDs)due to their unique properties,including highly anisotropic carrier transport,superior dark current suppression,and exceptional chemical stability.While the large-scale fabrication of RP layered perovskite SCs has been successfully achieved,the absence of systematic investigations into their mechanical strain properties poses a significant barrier to their application in flexible optoelectronic devices.This study introduces a polymer-SC-electrode-polymer lateral architecture PD,which employs a damage-free transfer technique to transfer centimeter-scale(C_6H_(5)C_(2)H_(4)NH_(3)_(2)PbI_(4)SC sheets(SC-sheets)with a thickness of~1μm from rigid substrates to flexible electrode substrates.This transfer process is facilitated by an organic polymer solution solidification-based method.The lateral device configuration effectively exploits the in-plane high electrical conductivity of RP layered perovskites,achieving responsivity of 728 mA/W,on/off ratio of 1.6×10^(4),specific detectivity of 2.14×10^(13)Jones,and external quantum efficiency of 222%.The self-sealing bilayer polymer sandwich structure imparts superior mechanical strain tolerance to the SCs,as demonstrated by mechanical bending tests that reveal an ultimate failure curvature radius of the SC-sheet in the range of 2.5-2.7 mm.Notably,even after superthreshold bendinginduced fragmentation,the crystal segments maintain robust adhesion to electrodes through polymer chain interactions,thereby preserving efficient PD functionality.This work represents a significant advancement in the development of flexible optoelectronics based on RP layered SCs and expands their applicability in next-generation wearable devices.展开更多
Ruddlesden-Popper(R-P)layered perovskite Sr_(3)Fe_(2)O_(7−δ)(SFO)is considered a promising cathode catalyst for solid oxide fuel cells(SOFCs)because of its unique layered structure.However,its insufficient oxygen red...Ruddlesden-Popper(R-P)layered perovskite Sr_(3)Fe_(2)O_(7−δ)(SFO)is considered a promising cathode catalyst for solid oxide fuel cells(SOFCs)because of its unique layered structure.However,its insufficient oxygen reduction reaction(ORR)activity at reduced temperatures leads to high polarization resistance,significantly degrading cell performance.This study introduces Nd-doped Sr_(2.9)Nd_(0.1)Fe_(2)O_(7−δ)(SNFO)as a candidate cathode material,focusing on its phase structure,oxygen desorption behavior,catalytic activity,and oxygen reduction reaction kinetics.At 700℃,the SNFO catalyst delivers outstanding ORR activity,with a polarization resistance of 0.20Ω·cm^(2) and a peak power density(PPD)of 803 mW·cm^(−2).Distribution of relaxation times(DRT)analysis revealed that the ORR kinetics of the SNFO cathode are primarily limited by the oxygen adsorption-dissociation process.In addition,density functional theory(DFT)calculations demonstrate that SNFO has a lower oxygen vacancy formation energy,an enhanced O_(2) adsorption capacity,and optimized overall oxygen dissociation energetics.This study identifies SNFO as a promising cathode electrocatalyst for SOFCs.展开更多
New two-layer Ruddlesden-Popper(RP)oxide La_(0.25)Sr_(2.75)FeNiO_(7-δ)(LSFN)in the combination of Sr_(3)Fe_(2)O_(7-δ) and La_(3)Ni_(2)O_(7-δ) was successfully synthesized and studied as the potential active single-...New two-layer Ruddlesden-Popper(RP)oxide La_(0.25)Sr_(2.75)FeNiO_(7-δ)(LSFN)in the combination of Sr_(3)Fe_(2)O_(7-δ) and La_(3)Ni_(2)O_(7-δ) was successfully synthesized and studied as the potential active single-phase and composite cathode for protonic ceramics fuel cells(PCFCs).LSFN with the tetragonal symmetrical structure(IMmmm)is confinned,and the co-existence of Fe^(3+)/Fe^(4+) and Ni^(3+)/Ni^(2+) couples is demonstrated by X-ray photoelectron spectrometer(XPS)analysis.The LSFN conductivity is apparently enhanced after Ni doping in Fe-site,and nearly three times those of Sr_(3)Fe_(2)O_(7-δ),which is directly related to the carrier concentration and conductor mechanism.Importantly,anode supported PCFCs using LSFN-BaZr_(0.1)Ce_(0.7)Y_(0.2)O_(3-δ)(LSFN-BZCY)composite cathode achieved high power density(426 mW·cm^(-2) at 650℃)and low electrode interface polarization resistance(0.26Ω·cm^(2)).Besides,distribution of relaxation time(DRT)function technology was further used to analyse the electrode polarization processes.The observed three peaks(Pl,P2,and P3)separated by DRT shifted to the high frequency region with the decreasing temperature,suggesting that the charge transfer at the electrode-electrolyte interfaces becomes more difficult at reduced temperatures.Preliminary results demonstrate that new two-layer RP phase LSFN can be a promising cathode candidate for PCFCs.展开更多
基金This work was financially supported by the National Key Research and Development Program of China(No.2017YFE0119700)the National Natural Science Found-ation of China(Nos.51961135107,51774034,and 51772026).
文摘Metal halide perovskite solar cells have attracted considerable attention because of their high-power conversion efficiency and costeffective solution-processable fabrication;however,they exhibit poor structural stability.Two-dimensional(2D)Ruddlesden-Popper(RP)perovskites could address the aforementioned issue and present excellent stability because of their hydrophobic organic spacer cations.However,the crystallographic orientation of 2D crystals should be perpendicular to the bottom substrates for charges to transport fast and be collected in solar cells.Moreover,controlling the crystallographic orientation of the 2D RP perovskites prepared by the solution process is difficult.Herein,we reviewed the progress of recent research regarding 2D RP perovskite films with the focus on the crystallographic orientation mechanism and orientation controlling methods.Furthermore,the current issues and prospects of 2D RP perovskites in the photovoltaic field were discussed to elucidate their development and application in the future.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272265,U1932217,11974246,12004252)the National Key R&D Program of China(Grant No.2018YFA0704300)+1 种基金the Shanghai Science and Technology Plan(Grant No.21DZ2260400)support from the Analytical Instrumentation Center(#SPST-AIC10112914),SPST,ShanghaiTech University.
文摘Recently,the discovery of superconductivity with a critical temperature Tc up to 80 K in Ruddlesden-Popper phases La_(n+1)Ni_(n)O_(3 n+1)(n=2)under pressure has garnered considerable attention.Up to now,the superconductivity was only observed in La_(3)Ni_(2)O_(7)single crystal grown with the optical-image float-ing zone furnace under oxygen pressure.It remains to be understood the effect of chemical doping on superconducting La_(3)Ni_(2)O_(7)as well as other Ruddlesden-Popper phases.Here,we systematically investi-gate the effect of external pressure and chemical doping on polycrystalline Ruddlesden-Popper phases.Our results demonstrate that the application of pressure and doping effectively tunes the transport prop-erties of Ruddlesden-Popper phases.We find pressure-induced superconductivity up to 86 K in La_(3)Ni_(2)O_(7)polycrystalline sample,while no signatures of superconductivity are observed in La_(2)NiO_(4)and La_(4)Ni_(3)O_(10)polycrystalline samples under high pressure up to 50 GPa.Our study sheds light on the exploration of high-Tc superconductivity in nickelates.
基金financially supported by the Natural Science Foundation of China(Grant Nos.52372226,52173263,62004167)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant Nos.2022JM-315,2023-JC-QN-0643)+4 种基金the National Key R&D Program of China(Grant No.2022YFB3603703)the Qinchuangyuan High-level Talent Project of Shaanxi(Grant No.QCYRCXM-2022-219)the Ningbo Natural Science Foundation(Grant No.2022J061)the Key Research and Development Program of Shaanxi(Grant No.2023GXLH-091)the Shccig-Qinling Program and the Fundamental Research Funds for the Central Universities。
文摘Two-dimensional Ruddlesden-Popper(2DRP)perovskite exhibits excellent stability in perovskite solar cells(PSCs)due to introducing hydrophobic long-chain organic spacers.However,the poor charge transporting property of bulky organic cation spacers limits the performance of 2DRP PSCs.Inspired by the Asite cation alloying strategy in 3D perovskites,2DRP perovskites with a binary spacer can promote charge transporting compared to the unary spacer counterparts.Herein,the superior MA-based 2DRP perovskite films with a binary spacer,including 3-guanidinopropanoic acid(GPA)and 4-fluorophenethylamine(FPEA)are realized.These films(GPA_(0.85)FPEA_(0.15))_(2)MA_(4)Pb_5I_(16)show good morphology,large grain size,decreased trap state density,and preferential orientation of the as-prepared film.Accordingly,the present 2DRP-based PSC with the binary spacer achieves a remarkable efficiency of 18.37%with a V_(OC)of1.15 V,a J_(SC)of 20.13 mA cm^(-2),and an FF of 79.23%.To our knowledge,the PCE value should be the highest for binary spacer MA-based 2DRP(n≤5)PSCs to date.Importantly,owing to the hydrophobic fluorine group of FPEA and the enhanced interlayer interaction by FPEA,the unencapsulated 2DRP PSCs based on binary spacers exhibit much excellent humidity stability and thermal stability than the unary spacer counterparts.
基金supported in part by the US National Science Foundation(NSF-2055734)a start-up fund from University of Illinois at Urbana-Champaignthe support of a scholarship from the China Scholarship Council(CSC)。
文摘Development of high performance electrocatalysts for oxygen evolution reaction (OER) in acidic media remains a challenge for direct water splitting using an electrolyzer.Recently,Ruddlesden-Popper phase Sr_(2)IrO_(4)was discovered to be an efficient OER catalyst because of its unique structure,which consists of layers of both rock salt and perovskite phases simultaneously.In this study,we prepared a series of B-site mixed,Ruddlesden-Popper phase of Sr_(2)(Ru_(x)Ir_(1-x))O_(4) and examined their electrocatalytic properties for OER in acidic media.Through partial substitution of Ru in the B-site of Ruddlesden-Popper phase materials,we achieved much enhanced OER performance for this series of Sr_(2)(Ru_(x)Ir_(1-x))O_(4)electrocatalysts,among which Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)exhibited the best catalytic activity with a current density of 8.06 m A/cm^(2) at 1.55 V and a Tafel slope of 47 m V/dec.This current density is three times higher than that of Sr_(2)Ir O_(4).The B-site mixed Sr_(2)(Ru_(0.5)Ir_(0.5))O_(4)retained good stability in acidic conditions for>24 h at 10 m A/cm^(2).A range of techniques were used to characterize the crystal and electronic structures of the Sr_(2)(Ru_(x)Ir_(1-x))O_(4)samples.Our data indicate that the improved OER performance can be correlated to the formation of high level of hydroxyl groups and the enhanced overlap between Ir/Ru 4d and O_(2)p orbitals,revealing a new way for the design of efficient OER electrocatalysts by regulating their composition and electronic structures.
基金supported by the National Key Research and Development Program of China(2017YFA0402800)the National Natural Science Foundation of China(51925206,U1932214)。
文摘Two-dimensional(2D)/quasi-2D perovskite solar cells(PSCs)incorporating organic spacer cations exhibit appealing ambient stability in comparison with their 3D analogs.Most reported organic spacer cations are based on ammonium,whereas formamidinium(FA^(+))has been seldom applied despite that FA has been extensively used in high-efficiency 3D PSCs.Herein,a novel FA-based organic spacer cation,4-chloro-phenylformamidinium(CPFA^(+)),is applied in quasi-2D Ruddlesden-Popper(RP)PSCs for the first time,and methylammonium chloride(MACl)is employed to promote crystal growth and orientation of perovskite film,resulting in high power conversion efficiency(PCE)with improved stability.Upon incorporating CPFA+organic spacer cation and MACl additive,high-quality quasi-2D CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)perovskite film forms,exhibiting improved crystal orientation,reduced trap state density,prolonged carrier lifetime and optimized energy level alignment.Consequently,the CPFA_(2)MA_(n-1)Pb_(n)(I_(0.857)Cl_(0.143))_(3n+1)(n=9)quasi-2D RP PSC devices deliver a highest PCE of 14.78%.Moreover,the un-encapsulated CPFA-based quasi-2D RP PSC devices maintain~80%of its original PCE after exceeding 2000 h storage under ambient condition,whereas the 3D MAPb I3counterparts retain only~45%of its original PCE.Thus,the ambient stability of quasi-2D RP PSC devices is improved obviously relative to its 3D MAPb I3counterpart.
基金supported by the Research Grants Council,University Grants Committee,Hong Kong SAR(Project Number:N_PolyU552/20)supported by the National Nature Science Foundation of China(22209138)Guangdong Basic and Applied Basic Research Foundation(2021A1515110464).
文摘Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.
基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2023A1515012878Natural Science Foundation of Anhui Province,Grant/Award Number:2008085ME134+2 种基金Australian Research Council Discovery Projects,Grant/Award Numbers:ARC DP200103315,ARC DP200103332Major Special Science and Technology Project of Anhui Province,Grant/Award Number:202103a07020007Key Research and Development Program of Anhui Province,Grant/Award Number:202104a05020057。
文摘Ni-Fe-based oxides are among the most promising catalysts developed to date for the bottleneck oxygen evolution reaction(OER)in water electrolysis.However,understanding and mastering the synergy of Ni and Fe remain challenging.Herein,we report that the synergy between Ni and Fe can be tailored by crystal dimensionality of Ni,Fe-contained Ruddlesden-Popper(RP)-type perovskites(La_(0.125)Sr_(0.875))n+1(Ni_(0.25)Fe_(0.75))nO3n+1(n=1,2,3),where the material with n=3 shows the best OER performance in alkaline media.Soft X-ray absorption spectroscopy spectra before and after OER reveal that the material with n=3 shows enhanced Ni/Fe-O covalency to boost the electron transfer as compared to those with n=1 and n=2.Further experimental investigations demonstrate that the Fe ion is the active site and the Ni ion is the stable site in this system,where such unique synergy reaches the optimum at n=3.Besides,as n increases,the proportion of unstable rock-salt layers accordingly decreases and the leaching of ions(especially Sr^(2+))into the electrolyte is suppressed,which induces a decrease in the leaching of active Fe ions,ultimately leading to enhanced stability.This work provides a new avenue for rational catalyst design through the dimensional strategy.
基金This work was supported by the National Science Foundation of China(NSFC),(Grant No.62022079)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2020115).
文摘Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP microwires(RPP-MWs)and compared it with a 2D-RPP photodetector.The results show that the RPP-MWs photodetector possesses a wider photoresponse range and higher responsivities of 233 A/W in the visible band and 30 A/W in the near-infrared(NIR)band.The analyses show that the synthesized RPP-MWs have a multi-layer,heterogeneous core-shell structure.This structure gives RPP-MWs a unique band structure,as well as abundant trap states and defect levels,which enable them to acquire better photoresponse performance.This configuration of RPP-MWs provides a new idea for the design and application of novel heterostructures.
基金supported by Australian Research Council Discovery Projects(DP230101625 and DP200103568)Australian Research Council Future Fel owships(FT180100387 and FT160100281)QUT ECR Scheme Grant(no.2020001179)
文摘Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas;however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.To address this issue,triphenylphosphine is proposed to be a reduction promotor for accelerating the reduction and migration of the target metal atoms,aiming to achieve the effective exsolution of metallic species from Ruddlesden-Popper-type parent perovskites.Upon oxygen evolution reaction,these exsolved metallic aggregates are reconstructed into oxyhydroxides as the real active centers.After further modification by lowpercentage iridium oxide nanoclusters,the optimal catalyst delivered an overpotential as low as 305 mV for generating the density of 10 mA cm^(-2),outperforming these reported noble metal-containing perovskite-based alkaline oxygen evolution reaction electrocatalysts.This work provides a potential approach to activate catalytically inert oxides through promoting surface metal exsolution and explores a novel class of Ruddlesden-Poppertype oxides for electrocatalytic applications.
基金supported by the Key Project of the National Key R&D Program of China(Grant No.2022YFA1404500)the National Natural Science Foundation of China(Grant Nos.12434017,62005183)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515010329)。
文摘Ruddlesden-Popper(RP)layered perovskite single crystals(SCs)have been widely utilized in high-performance and weather-resistant photodetectors(PDs)due to their unique properties,including highly anisotropic carrier transport,superior dark current suppression,and exceptional chemical stability.While the large-scale fabrication of RP layered perovskite SCs has been successfully achieved,the absence of systematic investigations into their mechanical strain properties poses a significant barrier to their application in flexible optoelectronic devices.This study introduces a polymer-SC-electrode-polymer lateral architecture PD,which employs a damage-free transfer technique to transfer centimeter-scale(C_6H_(5)C_(2)H_(4)NH_(3)_(2)PbI_(4)SC sheets(SC-sheets)with a thickness of~1μm from rigid substrates to flexible electrode substrates.This transfer process is facilitated by an organic polymer solution solidification-based method.The lateral device configuration effectively exploits the in-plane high electrical conductivity of RP layered perovskites,achieving responsivity of 728 mA/W,on/off ratio of 1.6×10^(4),specific detectivity of 2.14×10^(13)Jones,and external quantum efficiency of 222%.The self-sealing bilayer polymer sandwich structure imparts superior mechanical strain tolerance to the SCs,as demonstrated by mechanical bending tests that reveal an ultimate failure curvature radius of the SC-sheet in the range of 2.5-2.7 mm.Notably,even after superthreshold bendinginduced fragmentation,the crystal segments maintain robust adhesion to electrodes through polymer chain interactions,thereby preserving efficient PD functionality.This work represents a significant advancement in the development of flexible optoelectronics based on RP layered SCs and expands their applicability in next-generation wearable devices.
基金supported by the National Natural Science Foundation of China(No.52572219)the Natural Science Foundation of Heilongjiang Province(No.ZD2022E007).
文摘Ruddlesden-Popper(R-P)layered perovskite Sr_(3)Fe_(2)O_(7−δ)(SFO)is considered a promising cathode catalyst for solid oxide fuel cells(SOFCs)because of its unique layered structure.However,its insufficient oxygen reduction reaction(ORR)activity at reduced temperatures leads to high polarization resistance,significantly degrading cell performance.This study introduces Nd-doped Sr_(2.9)Nd_(0.1)Fe_(2)O_(7−δ)(SNFO)as a candidate cathode material,focusing on its phase structure,oxygen desorption behavior,catalytic activity,and oxygen reduction reaction kinetics.At 700℃,the SNFO catalyst delivers outstanding ORR activity,with a polarization resistance of 0.20Ω·cm^(2) and a peak power density(PPD)of 803 mW·cm^(−2).Distribution of relaxation times(DRT)analysis revealed that the ORR kinetics of the SNFO cathode are primarily limited by the oxygen adsorption-dissociation process.In addition,density functional theory(DFT)calculations demonstrate that SNFO has a lower oxygen vacancy formation energy,an enhanced O_(2) adsorption capacity,and optimized overall oxygen dissociation energetics.This study identifies SNFO as a promising cathode electrocatalyst for SOFCs.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.2019GF10).
文摘New two-layer Ruddlesden-Popper(RP)oxide La_(0.25)Sr_(2.75)FeNiO_(7-δ)(LSFN)in the combination of Sr_(3)Fe_(2)O_(7-δ) and La_(3)Ni_(2)O_(7-δ) was successfully synthesized and studied as the potential active single-phase and composite cathode for protonic ceramics fuel cells(PCFCs).LSFN with the tetragonal symmetrical structure(IMmmm)is confinned,and the co-existence of Fe^(3+)/Fe^(4+) and Ni^(3+)/Ni^(2+) couples is demonstrated by X-ray photoelectron spectrometer(XPS)analysis.The LSFN conductivity is apparently enhanced after Ni doping in Fe-site,and nearly three times those of Sr_(3)Fe_(2)O_(7-δ),which is directly related to the carrier concentration and conductor mechanism.Importantly,anode supported PCFCs using LSFN-BaZr_(0.1)Ce_(0.7)Y_(0.2)O_(3-δ)(LSFN-BZCY)composite cathode achieved high power density(426 mW·cm^(-2) at 650℃)and low electrode interface polarization resistance(0.26Ω·cm^(2)).Besides,distribution of relaxation time(DRT)function technology was further used to analyse the electrode polarization processes.The observed three peaks(Pl,P2,and P3)separated by DRT shifted to the high frequency region with the decreasing temperature,suggesting that the charge transfer at the electrode-electrolyte interfaces becomes more difficult at reduced temperatures.Preliminary results demonstrate that new two-layer RP phase LSFN can be a promising cathode candidate for PCFCs.
