Because of their better chemical stability and fascinating anisotropic characteristics,Dion-Jacobson(DJ)-layered halide perovskites,which owe crystallographic two-dimensional structures,have fascinated growing attenti...Because of their better chemical stability and fascinating anisotropic characteristics,Dion-Jacobson(DJ)-layered halide perovskites,which owe crystallographic two-dimensional structures,have fascinated growing attention for solar devices.DJ-layered halide perovskites have special structural and photoelectronic features that allow the van der Waals gap to be eliminated or reduced.DJ-layered halide perovskites have improved photophysical characteristics,resulting in improved photovoltaic performance.Nevertheless,owing to the nature of the solution procedure and the fast crystal development of DJ perovskite thin layers,the precursor compositions and processing circumstances can cause a variety of defects to occur.The application of additives can impact DJ perovskite crystallization and film generation,trap passivation in the bulk and/or at the surface,interface structure,and energetic tuning.This study discusses recent developments in additive engineering for DJ multilayer halide perovskite film production.Several additive-assisted bulk and interface optimization methodologies are summarized.Lastly,an overview of research developments in additive engineering in the production of DJ-layered halide perovskite solar cells is offered.展开更多
Interfacial defects and energy barrier would result in serious interfacial non-radiative recombination losses.In addition,the quality of perovskite films is highly dependent on deposition substrates.Consequently,there...Interfacial defects and energy barrier would result in serious interfacial non-radiative recombination losses.In addition,the quality of perovskite films is highly dependent on deposition substrates.Consequently,there is an urgent desire to develop multifunctional interface modulators to manage the interface between electron transport layer and perovskite layer.Here,we report a multifunctional buried interface modulation strategy that 4-fluoro-phenylammonium tetrafluoroborate (FBABF_(4)) consisting of simultaneously fluorinated anion and cation is inserted between SnO_(2)layer and perovskite layer.It is uncovered by time-of-flight secondary ion mass spectroscopy that the anion and cation in modifier are mainly located at this interface,which is put down to coordination bond of the fluorine atom on BF_(4)^(-) with SnO_(2),and the hydrogen bond of the fluorine atom on FBA^(+) with formamidinium.This suggests that simultaneous fluorination of anion and cation in the ionic liquid molecule is of crucial importance to ameliorate interfacial contact through chemical linker.The interface modification approach enables the realization of interfacial defect passivation,interfacial energy band alignment modulation,and perovskite crystallization manipulation,which are translated into enhanced efficiency and stability as well as significantly suppressed hysteresis.The multiple functions of FBABF_(4) endow the modified solar cells excellent photovoltaic performance with an efficiency exceeding 23%along with appealing long-term stability.This work highlights the critical role of fluorination strategy in engineering multifunctional organic salt modulators for improving interfacial contact.展开更多
Zinc oxide nanoparticles with different sizes and shapes have been synthesized in polyol using a bottom-up approach. We have studied the scale-up of the process to massively produce high quality nanoparticles of contr...Zinc oxide nanoparticles with different sizes and shapes have been synthesized in polyol using a bottom-up approach. We have studied the scale-up of the process to massively produce high quality nanoparticles of controlled size and shape. The scale-up strategy required the effective mixing of reagents using either axial or radial mixing configurations and was experimentally validated by comparing structural properties of particles obtained in a small and a large size reactor. In addition, the flow patterns in these reactors have been calculated using three-dimensional turbulent computational fluid dynamics (CFD) simulations. Our results indicate a strong connection between the flow patterns, as obtained by CFD simulations, and the size and shape of the particles. Actually, our pilot scale reactor allowed producing sample aliquots of ~50 grams with nanoparticle sizes ranging from 8 nm to 600 nm and aspect ratio varying from 1 (nanospheres) to 20 (nanorods). After their synthesis, these two nanoparticle classes have been tested as building blocks in D149-dye-sensitized solar cell (DSSC). The measured power conversion efficiency (PCE) was 4.66% for nanorods shaped particles and 4.21% for nanospheres. These values were significantly higher than the 3.90% PCE obtained with commercial Degussa VP20 ZnO nanoparticles.展开更多
Labor-intensive,trial-and-error methods are frequently employed for modifying the perovskite surface to mitigate trap defects.There is an urgent need for rationally designed and efficient molecular passivators.To addr...Labor-intensive,trial-and-error methods are frequently employed for modifying the perovskite surface to mitigate trap defects.There is an urgent need for rationally designed and efficient molecular passivators.To address the performance and stability challenges caused by defects in polycrystalline perovskite,we have rationally designed and tailored passivation molecules,4-(trifluoromethyl)benzoic anhydride(TFBA),ethyl 4-(trifluoromethyl)benzoate(TFB),and 4-(trifluoromethyl)benzoic acid(PTF),to minimize interfacial energy loss and modulate the bandgap alignment for achieving efficient perovskite solar cells(PSCs).These molecules could target the perovskite surface defects,particularly Pb-I antisite defects,with the-COOH and trifluoromethyl functional groups at the edges.Among them,PTF exhibited superior passivation performance by coordinat-ing its carboxyl group withPb2+,effectively suppressing non-radiative recombination.Additionally,the fluorine sites in these molecules corrected lattice distortions and stabilized the perovskite structure through hydrogen bonding with MA/FA cations,reducing ion migration,and enhancing moisture resistance.As a result,PTF-modified PSCs achieved an efficiency of 25.57%and maintained over 85%of their initial efficiency after 1600 h of aging.This study provides a clear pathway for optimizing passivation strategies through rational molecular design.展开更多
Trivalent lanthanides in wide bandgap fluoride or phosphate hosts can present persistent luminescence between 200 nm and 1.7 μm after charging by X-rays.Mechanisms are reviewed and applications envisioned.
Fe-based materials have received more and more interests in recent years as candidates to fabricate bioresorbable stents due to their appropriate mechanical properties and biocompatibility.However,the low degradation ...Fe-based materials have received more and more interests in recent years as candidates to fabricate bioresorbable stents due to their appropriate mechanical properties and biocompatibility.However,the low degradation rate of Fe is a serious limitation for such application.To overcome this critical issue,many efforts have been devoted to accelerate the corrosion rate of Fe-based stents,through the structural and surface modification of Fe matrix.As stents are implantable devices,the released corrosion products(Fe^(2+)ions)in vessels may alter the metabolism,by generating reactive oxygen species(ROS),which might in turn impact the biosafety of Fe-based stents.These considerations emphasize the importance of combining knowledge in both materials and biological science for the development of efficient and safe Fe-based stents,although there are still only limited numbers of reviews regarding this interdisciplinary field.This review aims to provide a concise overview of the main strategies developed so far to design Fe-based stents with accelerated degradation,highlighting the fundamental mechanisms of corrosion and the methods to study them as well as the reported approaches to accelerate the corrosion rates.These approaches will be divided into four main sections,focusing on(i)increased active surface areas,(ii)tailored microstructures,(iii)creation of galvanic reactions(by alloying,ion implantation or surface coating of noble metals)and(iv)decreased local pH induced by degradable surface organic layers.Recent advances in the evaluation of the in vitro biocompatibility of the final materials and ongoing in vivo tests are also provided.展开更多
Solar energy,a renewable and abundant source of energy,offers considerable potential as a sustainable alternative to fossil fuels.Over the past few decades,various technologies have been developed to harness and conve...Solar energy,a renewable and abundant source of energy,offers considerable potential as a sustainable alternative to fossil fuels.Over the past few decades,various technologies have been developed to harness and convert solar energy into thermal,electrical,and chemical forms[1].Photovoltaic(PV)technology has attracted significant at-tention owing to its ability to directly convert sunlight into electricity.Among the emerging PV devices,perovskite solar cells(PSCs)have emerged as leading contenders,exhibiting a remarkable increase in power conversion efficiency(PCE)from below 15%to over 26%in just a decade.This performance is comparable to that of established crys-talline Si(c-Si)cells.The low cost of raw materials and straightforward manufacturing processes result in a low estimated large-scale manu-facturing cost for PSCs,which is only 50%that of c-Si devices.Fur-thermore,the mechanical flexibility and high power-to-weight ratio of PSCs render them suitable for lightweight and innovative applications such as building-integrated PV and wearable electronics[2].展开更多
The application of Mg and its alloys in 3C(i.e.Computer,Communication and Consumer Electronic)industries requires a strict combination of corrosion resistance and low electrical contact resistance(ECR).The conventiona...The application of Mg and its alloys in 3C(i.e.Computer,Communication and Consumer Electronic)industries requires a strict combination of corrosion resistance and low electrical contact resistance(ECR).The conventional design of conversion coating relies on a thick and compact layer to offer active protectiveness but compromises the electric conductivity.In this work,phosphate conversion coatings(PCC)with low electrical contact resistance were prepared on the sand-cast and die-cast Mg alloy AZ91D,respectively.The microstructural differences,ECR and corrosion resistance were observed and compared.Results show that the PCCs on die-cast alloy have a thickness of 300-400 nm,and are more compact than those on sand-cast counterparts.Interestingly,PCCs of the die-cast exhibit lower ECR,which indicates a mild impact of the improved compactness on ECR.Meanwhile,corrosion resistance of the PCCs on die-cast alloy is greatly improved,which is attributed to the intensified micro-galvanic effect through the grain refinement of the die-cast alloy.It evidently promotes the electrochemical reactions during the conversion treatment to yield high quality PCC.展开更多
Mg–Li alloys are one of the lightest structural materials,but suffer from severe corrosion due to the hyperactivity of Mg and Li.In this work,an electrically conductive and corrosion-resistant chemical conversion coa...Mg–Li alloys are one of the lightest structural materials,but suffer from severe corrosion due to the hyperactivity of Mg and Li.In this work,an electrically conductive and corrosion-resistant chemical conversion coating was fabricated on a duplex Mg–Li alloy LA103Z by two different routes:the first route using a conventional immersion treatment(Im-PCCs);and the second route using a brushing conversion treatment(Br-PCCs).Results demonstrate that chemical composition of conversion coatings remained,but surface morphology was altered.The Im-PCC depicts many lamellar CaHPO_(4)when the immersion time was longer than 60 s.The Br-PCC shows no lamellas on surface till a treatment time of 120 s.These lamellar crystals are detrimental to the electrical contact resistance(ECR),and the ECR for the Br-PCC was one order of magnitude lower than that for the Im-PCCs.Corrosion resistance for Br-PCCs,however,was slightly lower than Im-PCCs.展开更多
基金Min Liu thanks the CSC for funding his PhD scholarship(grant number 202008120110)The ANR agency is acknowledged for financial support via the ChemSta project ANR-21-CE05-0022.
文摘Because of their better chemical stability and fascinating anisotropic characteristics,Dion-Jacobson(DJ)-layered halide perovskites,which owe crystallographic two-dimensional structures,have fascinated growing attention for solar devices.DJ-layered halide perovskites have special structural and photoelectronic features that allow the van der Waals gap to be eliminated or reduced.DJ-layered halide perovskites have improved photophysical characteristics,resulting in improved photovoltaic performance.Nevertheless,owing to the nature of the solution procedure and the fast crystal development of DJ perovskite thin layers,the precursor compositions and processing circumstances can cause a variety of defects to occur.The application of additives can impact DJ perovskite crystallization and film generation,trap passivation in the bulk and/or at the surface,interface structure,and energetic tuning.This study discusses recent developments in additive engineering for DJ multilayer halide perovskite film production.Several additive-assisted bulk and interface optimization methodologies are summarized.Lastly,an overview of research developments in additive engineering in the production of DJ-layered halide perovskite solar cells is offered.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62004058, U21A2076, 21701041, 52071048)the Nature Science Foundation of Hebei Province (Grant No. F2020202022)+4 种基金the Open Fund of the State Key Laboratory of Integrated Optoelectronics (Grant No. IOSKL2020KF09)the State Key Laboratory of Reliability and Intelligence of Electrical Equipment (Grant No. EERI_PI20200005)supported by the Support plan for Overseas Students to Return to China for Entrepreneurship and Innovation (Grant No. cx2020003)the Fundamental Research Funds for the Central Universities (Grant No. 2020CDJ-LHZZ-074)the Natural Science Foundation of Chongqing (Grant No. cstc2020jcyjmsxmX0629)。
文摘Interfacial defects and energy barrier would result in serious interfacial non-radiative recombination losses.In addition,the quality of perovskite films is highly dependent on deposition substrates.Consequently,there is an urgent desire to develop multifunctional interface modulators to manage the interface between electron transport layer and perovskite layer.Here,we report a multifunctional buried interface modulation strategy that 4-fluoro-phenylammonium tetrafluoroborate (FBABF_(4)) consisting of simultaneously fluorinated anion and cation is inserted between SnO_(2)layer and perovskite layer.It is uncovered by time-of-flight secondary ion mass spectroscopy that the anion and cation in modifier are mainly located at this interface,which is put down to coordination bond of the fluorine atom on BF_(4)^(-) with SnO_(2),and the hydrogen bond of the fluorine atom on FBA^(+) with formamidinium.This suggests that simultaneous fluorination of anion and cation in the ionic liquid molecule is of crucial importance to ameliorate interfacial contact through chemical linker.The interface modification approach enables the realization of interfacial defect passivation,interfacial energy band alignment modulation,and perovskite crystallization manipulation,which are translated into enhanced efficiency and stability as well as significantly suppressed hysteresis.The multiple functions of FBABF_(4) endow the modified solar cells excellent photovoltaic performance with an efficiency exceeding 23%along with appealing long-term stability.This work highlights the critical role of fluorination strategy in engineering multifunctional organic salt modulators for improving interfacial contact.
文摘Zinc oxide nanoparticles with different sizes and shapes have been synthesized in polyol using a bottom-up approach. We have studied the scale-up of the process to massively produce high quality nanoparticles of controlled size and shape. The scale-up strategy required the effective mixing of reagents using either axial or radial mixing configurations and was experimentally validated by comparing structural properties of particles obtained in a small and a large size reactor. In addition, the flow patterns in these reactors have been calculated using three-dimensional turbulent computational fluid dynamics (CFD) simulations. Our results indicate a strong connection between the flow patterns, as obtained by CFD simulations, and the size and shape of the particles. Actually, our pilot scale reactor allowed producing sample aliquots of ~50 grams with nanoparticle sizes ranging from 8 nm to 600 nm and aspect ratio varying from 1 (nanospheres) to 20 (nanorods). After their synthesis, these two nanoparticle classes have been tested as building blocks in D149-dye-sensitized solar cell (DSSC). The measured power conversion efficiency (PCE) was 4.66% for nanorods shaped particles and 4.21% for nanospheres. These values were significantly higher than the 3.90% PCE obtained with commercial Degussa VP20 ZnO nanoparticles.
基金supported by the National Natural Science Foundation of China(U21A2076,62274018,52462031)The S&T Program of Hebei(24464401D)+3 种基金The Central Guidance on Local Science and Technology Development Fund of Hebei Province(226Z4305G)Hebei Province Higher Education Science and Technology Research Project(JZX2024030)Shijiazhuang Basic Research Project at Hebei-based Universities(241790847A)The Natural Science Foundation of Hebei Province(E2024202086,E2024202300).
文摘Labor-intensive,trial-and-error methods are frequently employed for modifying the perovskite surface to mitigate trap defects.There is an urgent need for rationally designed and efficient molecular passivators.To address the performance and stability challenges caused by defects in polycrystalline perovskite,we have rationally designed and tailored passivation molecules,4-(trifluoromethyl)benzoic anhydride(TFBA),ethyl 4-(trifluoromethyl)benzoate(TFB),and 4-(trifluoromethyl)benzoic acid(PTF),to minimize interfacial energy loss and modulate the bandgap alignment for achieving efficient perovskite solar cells(PSCs).These molecules could target the perovskite surface defects,particularly Pb-I antisite defects,with the-COOH and trifluoromethyl functional groups at the edges.Among them,PTF exhibited superior passivation performance by coordinat-ing its carboxyl group withPb2+,effectively suppressing non-radiative recombination.Additionally,the fluorine sites in these molecules corrected lattice distortions and stabilized the perovskite structure through hydrogen bonding with MA/FA cations,reducing ion migration,and enhancing moisture resistance.As a result,PTF-modified PSCs achieved an efficiency of 25.57%and maintained over 85%of their initial efficiency after 1600 h of aging.This study provides a clear pathway for optimizing passivation strategies through rational molecular design.
文摘Trivalent lanthanides in wide bandgap fluoride or phosphate hosts can present persistent luminescence between 200 nm and 1.7 μm after charging by X-rays.Mechanisms are reviewed and applications envisioned.
基金financed by Agence Nationale de la Recherche(BIORESORB ANR-21-CE18-0012-01)Y.Z.is granted by China Scholarship Council(N◦CSC 202106340022).
文摘Fe-based materials have received more and more interests in recent years as candidates to fabricate bioresorbable stents due to their appropriate mechanical properties and biocompatibility.However,the low degradation rate of Fe is a serious limitation for such application.To overcome this critical issue,many efforts have been devoted to accelerate the corrosion rate of Fe-based stents,through the structural and surface modification of Fe matrix.As stents are implantable devices,the released corrosion products(Fe^(2+)ions)in vessels may alter the metabolism,by generating reactive oxygen species(ROS),which might in turn impact the biosafety of Fe-based stents.These considerations emphasize the importance of combining knowledge in both materials and biological science for the development of efficient and safe Fe-based stents,although there are still only limited numbers of reviews regarding this interdisciplinary field.This review aims to provide a concise overview of the main strategies developed so far to design Fe-based stents with accelerated degradation,highlighting the fundamental mechanisms of corrosion and the methods to study them as well as the reported approaches to accelerate the corrosion rates.These approaches will be divided into four main sections,focusing on(i)increased active surface areas,(ii)tailored microstructures,(iii)creation of galvanic reactions(by alloying,ion implantation or surface coating of noble metals)and(iv)decreased local pH induced by degradable surface organic layers.Recent advances in the evaluation of the in vitro biocompatibility of the final materials and ongoing in vivo tests are also provided.
基金supported by the National Natural Science Foundation of China(Grant nos.U23A20141,22279154,and 52272255)the Major Basic Research Projects of the Shandong Natural Science Foundation(Grant no.ZR2021ZD25)+2 种基金Taishan Scholars of Shandong Province(No.ts201511063)the Youth Innovation Promotion Association of CAS(2023218)the Qingdao New Energy Shandong Laboratory of Strengthening Foundation Plan(QIBEBT/SEI/QNESL S202305).
文摘Solar energy,a renewable and abundant source of energy,offers considerable potential as a sustainable alternative to fossil fuels.Over the past few decades,various technologies have been developed to harness and convert solar energy into thermal,electrical,and chemical forms[1].Photovoltaic(PV)technology has attracted significant at-tention owing to its ability to directly convert sunlight into electricity.Among the emerging PV devices,perovskite solar cells(PSCs)have emerged as leading contenders,exhibiting a remarkable increase in power conversion efficiency(PCE)from below 15%to over 26%in just a decade.This performance is comparable to that of established crys-talline Si(c-Si)cells.The low cost of raw materials and straightforward manufacturing processes result in a low estimated large-scale manu-facturing cost for PSCs,which is only 50%that of c-Si devices.Fur-thermore,the mechanical flexibility and high power-to-weight ratio of PSCs render them suitable for lightweight and innovative applications such as building-integrated PV and wearable electronics[2].
基金financially supported by the National Natural Science Foundation of China(Nos.51531007 and 51771050)the China Postdoctoral Science Foundation(No.2019M651128)+2 种基金the National Program for the Young Top-notch Professionalsthe Fundamental Research Funds for the Central Universities(No.N170205002)the Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2020-046)
文摘The application of Mg and its alloys in 3C(i.e.Computer,Communication and Consumer Electronic)industries requires a strict combination of corrosion resistance and low electrical contact resistance(ECR).The conventional design of conversion coating relies on a thick and compact layer to offer active protectiveness but compromises the electric conductivity.In this work,phosphate conversion coatings(PCC)with low electrical contact resistance were prepared on the sand-cast and die-cast Mg alloy AZ91D,respectively.The microstructural differences,ECR and corrosion resistance were observed and compared.Results show that the PCCs on die-cast alloy have a thickness of 300-400 nm,and are more compact than those on sand-cast counterparts.Interestingly,PCCs of the die-cast exhibit lower ECR,which indicates a mild impact of the improved compactness on ECR.Meanwhile,corrosion resistance of the PCCs on die-cast alloy is greatly improved,which is attributed to the intensified micro-galvanic effect through the grain refinement of the die-cast alloy.It evidently promotes the electrochemical reactions during the conversion treatment to yield high quality PCC.
基金financially supported by the National Natural Science Foundation of China(52201066 and U21A2045)the National Program for the Young Top-notch Professionals+3 种基金the support from the National Training Program of Innovation and Entrepreneurship for Undergraduates(240115 and 230117)the Shanghai Aerospace Science and Technology Innovation Fund(SAST2020-046)the Fundamental Research Funds for the Central Universities(N2224002-21)the Natural Science Foundation of Shanghai(20ZR1424200)
文摘Mg–Li alloys are one of the lightest structural materials,but suffer from severe corrosion due to the hyperactivity of Mg and Li.In this work,an electrically conductive and corrosion-resistant chemical conversion coating was fabricated on a duplex Mg–Li alloy LA103Z by two different routes:the first route using a conventional immersion treatment(Im-PCCs);and the second route using a brushing conversion treatment(Br-PCCs).Results demonstrate that chemical composition of conversion coatings remained,but surface morphology was altered.The Im-PCC depicts many lamellar CaHPO_(4)when the immersion time was longer than 60 s.The Br-PCC shows no lamellas on surface till a treatment time of 120 s.These lamellar crystals are detrimental to the electrical contact resistance(ECR),and the ECR for the Br-PCC was one order of magnitude lower than that for the Im-PCCs.Corrosion resistance for Br-PCCs,however,was slightly lower than Im-PCCs.
