Lead halide perovskite scintillators have recently received extensive research attention owing to their short fluorescence lifetimes,low detection limits,and ease of fabrication compared to traditional scintillators.T...Lead halide perovskite scintillators have recently received extensive research attention owing to their short fluorescence lifetimes,low detection limits,and ease of fabrication compared to traditional scintillators.The nontoxic cerium-doped lead-free perovskites with intrinsically efficient and short lifetime d–f transitions are a prospective replacement for the toxic Pb^(2+).Here,we demonstrated Ce-doped cesium lanthanide chloride perovskites (Cs_(3)LnCl_(6),Ln=Gd,Y,Lu) synthesized through a facile solution method for the first time.These perovskites exhibit blue-violet emission,which arises from Ce 5d→4f transitions.Among three types of Cs_(3)LnCl_(6) perovskites,Ce:Cs_(3)LuCl_(6) exhibited high photoluminescence quantum yield (PLQY) of 82%and a short excited-state lifetime of approximately 34 ns.When utilized as X-ray scintillators,Ce:Cs_(3)LuCl_(6) crystals display a high light yield of 8120 photons per MeV and a low detection limit of 36.8 n Gy air s^(-1).Importantly,the figure of merit (FoM),representing the ratio of light yield to decay time,reaches 239,which is the highest reported value for lead-free perovskite scintillators up to now.Additionally,the fabrication of perovskite/PMMA films was undertaken for practical demonstrations in X-ray imaging,resulting in the attainment of a resolution of up to 8.38 lp/mm.We anticipate that this work will inspire the utilization of Ce-doped Cs_(3)LnCl_(6) perovskites in ultrafast scintillation applications such as high-energy physics,nuclear reaction monitoring,and dynamic X-ray imaging.展开更多
We fabricate flexible conductive and transparent graphene films on position-emission-tomography substrates and prepare large area graphene films by graphite oxide sheets with the new technical process. The multi-layer...We fabricate flexible conductive and transparent graphene films on position-emission-tomography substrates and prepare large area graphene films by graphite oxide sheets with the new technical process. The multi-layer graphene oxide sheets can be chemically reduced by HNO3 and HI to form a highly conductive graphene film on a substrate at lower temperature. The reduced graphene oxide sheets show a high conductivity sheet with resistance of 476Ω/sq and transmittance of 76% at 550nm （6 layers）. The technique used to produce the transparent conductive graphene thin film is facile, inexpensive, and can be tunable for a large area production applied for electronics or touch screens.展开更多
Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO_(2).A possible solution for the transport of H_(2)in a safe and low-cost way is in the fo...Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO_(2).A possible solution for the transport of H_(2)in a safe and low-cost way is in the form of liquid organic hydrogen carriers(LOHCs).As an alternative to loading LOHC with H_(2)via a two-step procedure involving preliminary electrolytic production of H_(2)and subsequent chemical hydrogenation of the LOHC,we explore here the possibility of electrochemical hydrogen storage(EHS)via conversion of proton of a proton donor into a hydrogen atom involved in covalent bonds with the LOHC(R)via a protoncoupled electron transfer(PCET)reaction:2nH^(+)+2ne^(-)+Rox■n H_(2)^(0)Rred.We chose 9-fluorenone/fluorenol(Fnone/Fnol)conversion as such a model PCET reaction.The electrochemical activation of Fnone via two sequential electron transfers was monitored with in-situ and operando spectroscopies in absence and in presence of different alcohols as proton donors of different reactivity,which enabled us to both quantify and get the mechanistic insight on PCET.The possibility of hydrogen extraction from the loaded carrier molecule was illustrated by chemical activation.展开更多
Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent year...Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.展开更多
Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced ...Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced into perovskites.The experiments and calculations reveal that betulin can effectively passivate the uncoordinated lead ions in perovskites via sharing the lone pair electrons of hydroxyl group,promoting charge transport.As a result,the power conversion efficiencies of the p-i-n planar PSCs remarkably increase from 19.14%to 21.15%,with the improvement of other parameters.The hydrogen bonds of betulin lock methylamine and halogen ions along the grain boundaries and on the film surface and thus suppress ion migration,further stabilizing perovskite crystal structures.These positive effects enable the PSCs to maintain 90%of the initial efficiency after 30 days in ambient air with 60%±5%relative humidity,75%after 300 h aging at 85℃,and 55%after 250 h light soaking,respectively.This work opens a new pathway for using nontoxic and low-cost biomaterials from forest to make highly efficient and stable PSCs.展开更多
The tremendous amount of wasted heat from solar radiation and industry dissipation has motivated the development of thermoelectric concepts that directly convert heat into electricity.The main challenge in practical a...The tremendous amount of wasted heat from solar radiation and industry dissipation has motivated the development of thermoelectric concepts that directly convert heat into electricity.The main challenge in practical applications for thermoelectrics is the high cost from both materials and manufacturing.Recently,breakthrough progresses in ionic thermoelectrics open up new possibilities to charge energy storage devices when submitted to a temperature gradient.The charging voltage is internally from the ionic Seebeck effect of the electrolyte between two electrodes.Hence electrolytes with high thermoelectric figure of merit are classified as ionic thermoelectric materials.Most ionic thermoelectric materials are composed of abundant elements,and they can generate hundreds of times larger thermal voltage than that of electronic materials.This emerging thermoelectric category brings new hope to fabricate low cost and large area heat-to-energy conversion devices,and triggers a renewed interest for ionic thermodiffusion.In this review,we summarize the state of the art in the new field of ionic thermoelectrics,from the driving force of the ionic thermodiffusion to material and application developments.We present a general map of ionic thermoelectric materials,discuss the unique characters of each type of the reported electrolytes,and propose potential optimization and future topics of ionic thermoelectrics.展开更多
Photo-generated carrier recombination loss at the CZTSSe/Cd S front interface is a key issue to the opencircuit voltage(V_(OC)) deficit of Cu_(2)ZnSnS_(x)Se_(4-x)(CZTSSe) solar cells. Here, by the aid of an easy-handl...Photo-generated carrier recombination loss at the CZTSSe/Cd S front interface is a key issue to the opencircuit voltage(V_(OC)) deficit of Cu_(2)ZnSnS_(x)Se_(4-x)(CZTSSe) solar cells. Here, by the aid of an easy-handling spin-coating method, a thin PCBM([6,6]-phenyl-C61-butyric acid methyl ester) layer as an electron extraction layer has been introduced on the top of CdS buffer layer to modify CZTSSe/CdS/ZnO-ITO(In_(2)O_(3):Sn) interfacial properties. Based on Sn^(4+)/DMSO(dimethyl sulfoxide) solution system, a totalarea efficiency of 12.87% with a VOC of 529 m V has been achieved. A comprehensive investigation on the influence of PCBM layer on carrier extraction, transportation and recombination processes has been carried out. It is found that the PCBM layer can smooth over the Cd S film roughness, thus beneficial for a dense and flat window layer. Furthermore, this CZTSSe/Cd S/PCBM heterostructure can accelerate carrier separation and extraction and block holes from the front interface as well, which is mainly ascribed to the downward band bending of the absorber and a widened space charge region. Our work provides a feasible way to improve the front interfacial property and the cell performance of CZTSSe solar cells by the aid of organic interfacial materials.展开更多
Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
Lithium metal batteries(LMBs)with high energy density are impeded by the instability of solid electrolyte interface(SEI)and the uncontrolled growth of lithium(Li)dendrite.To mitigate these challenges,optimizing the SE...Lithium metal batteries(LMBs)with high energy density are impeded by the instability of solid electrolyte interface(SEI)and the uncontrolled growth of lithium(Li)dendrite.To mitigate these challenges,optimizing the SEI structure and Li deposition behavior is the key to stable LMBs.This study novelty proposes a facile synthesis of MgF_(2)/carbon(C)nanocomposite through the mechanochemical reaction between metallic Mg and polytetrafluoroethylene(PTFE)powders,and its modified polypropylene(PP)separator enhances LMB performance.The in-situ formed highly conductive fluorine-doped C species play a crucial role in facilitating ion/electron transport,thereby accelerating electrochemical kinetics and altering Li deposition direction.During cycling,the in-situ reaction between MgF_(2)and Li leads to the formation of LiMg alloy,along with a LiF-rich SEI layer,which reduces the nucleation overpotential and reinforces the interphase strength,leading to homogeneous Li deposition with dendrite-free feature.Benefiting from these merits,the Li metal is densely and uniformly deposited on the MgF_(2)/C@PP separator side rather than on the current collector side.Furthermore,the symmetric cell with MgF_(2)/C@PP exhibits superb Li plating/stripping performance over 2800 h at 1 mA cm^(-2)and 2 mA h cm^(-2).More importantly,the assembled Li@MgF_(2)/C@PPILiFePO4full cell with a low negative/positive ratio of 3.6delivers an impressive cyclability with 82.7%capacity retention over 1400 cycles at 1 C.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 22075043, 21875034, 12274075, 62375142)。
文摘Lead halide perovskite scintillators have recently received extensive research attention owing to their short fluorescence lifetimes,low detection limits,and ease of fabrication compared to traditional scintillators.The nontoxic cerium-doped lead-free perovskites with intrinsically efficient and short lifetime d–f transitions are a prospective replacement for the toxic Pb^(2+).Here,we demonstrated Ce-doped cesium lanthanide chloride perovskites (Cs_(3)LnCl_(6),Ln=Gd,Y,Lu) synthesized through a facile solution method for the first time.These perovskites exhibit blue-violet emission,which arises from Ce 5d→4f transitions.Among three types of Cs_(3)LnCl_(6) perovskites,Ce:Cs_(3)LuCl_(6) exhibited high photoluminescence quantum yield (PLQY) of 82%and a short excited-state lifetime of approximately 34 ns.When utilized as X-ray scintillators,Ce:Cs_(3)LuCl_(6) crystals display a high light yield of 8120 photons per MeV and a low detection limit of 36.8 n Gy air s^(-1).Importantly,the figure of merit (FoM),representing the ratio of light yield to decay time,reaches 239,which is the highest reported value for lead-free perovskite scintillators up to now.Additionally,the fabrication of perovskite/PMMA films was undertaken for practical demonstrations in X-ray imaging,resulting in the attainment of a resolution of up to 8.38 lp/mm.We anticipate that this work will inspire the utilization of Ce-doped Cs_(3)LnCl_(6) perovskites in ultrafast scintillation applications such as high-energy physics,nuclear reaction monitoring,and dynamic X-ray imaging.
基金Supported by the Basic Research Program of Nanjing University of Posts and Telecommunications under Grant No NY212002the Innovative Research Team in University under Grant No IRT1148the 2014 Shuangchuang Program of Jiangsu Province
文摘We fabricate flexible conductive and transparent graphene films on position-emission-tomography substrates and prepare large area graphene films by graphite oxide sheets with the new technical process. The multi-layer graphene oxide sheets can be chemically reduced by HNO3 and HI to form a highly conductive graphene film on a substrate at lower temperature. The reduced graphene oxide sheets show a high conductivity sheet with resistance of 476Ω/sq and transmittance of 76% at 550nm （6 layers）. The technique used to produce the transparent conductive graphene thin film is facile, inexpensive, and can be tunable for a large area production applied for electronics or touch screens.
基金financially supported by the Swedish Research Council(grant 2016-05990)the Knut and Alice Wallenberg Foundation(H2O2 and Cellfion)the Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Link?ping University(Faculty Grant SFO-Mat-Li U No.200900971)。
文摘Green hydrogen is identified as one of the prime clean energy carriers due to its high energy density and a zero emission of CO_(2).A possible solution for the transport of H_(2)in a safe and low-cost way is in the form of liquid organic hydrogen carriers(LOHCs).As an alternative to loading LOHC with H_(2)via a two-step procedure involving preliminary electrolytic production of H_(2)and subsequent chemical hydrogenation of the LOHC,we explore here the possibility of electrochemical hydrogen storage(EHS)via conversion of proton of a proton donor into a hydrogen atom involved in covalent bonds with the LOHC(R)via a protoncoupled electron transfer(PCET)reaction:2nH^(+)+2ne^(-)+Rox■n H_(2)^(0)Rred.We chose 9-fluorenone/fluorenol(Fnone/Fnol)conversion as such a model PCET reaction.The electrochemical activation of Fnone via two sequential electron transfers was monitored with in-situ and operando spectroscopies in absence and in presence of different alcohols as proton donors of different reactivity,which enabled us to both quantify and get the mechanistic insight on PCET.The possibility of hydrogen extraction from the loaded carrier molecule was illustrated by chemical activation.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51902101 and 21875203)the Natural Science Foundation of Hunan Province(Nos.2021JJ40044 and 2023JJ50287)Natural Science Foundation of Jiangsu Province(No.BK20201381).
文摘Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.
基金supported by the National Natural Science Foundation of China(21875067,51811530011,11604099)the Fundamental Research Funds for the Central Universities,Shanghai Rising-Star(19QA1403100)+2 种基金ECNU Multifunctional Platform for Innovation(006)the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support。
文摘Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced into perovskites.The experiments and calculations reveal that betulin can effectively passivate the uncoordinated lead ions in perovskites via sharing the lone pair electrons of hydroxyl group,promoting charge transport.As a result,the power conversion efficiencies of the p-i-n planar PSCs remarkably increase from 19.14%to 21.15%,with the improvement of other parameters.The hydrogen bonds of betulin lock methylamine and halogen ions along the grain boundaries and on the film surface and thus suppress ion migration,further stabilizing perovskite crystal structures.These positive effects enable the PSCs to maintain 90%of the initial efficiency after 30 days in ambient air with 60%±5%relative humidity,75%after 300 h aging at 85℃,and 55%after 250 h light soaking,respectively.This work opens a new pathway for using nontoxic and low-cost biomaterials from forest to make highly efficient and stable PSCs.
基金support by the French National Research Agency through grant ANR-19-CE300012by the European Research Council(ERC)through grant No.772725。
文摘The tremendous amount of wasted heat from solar radiation and industry dissipation has motivated the development of thermoelectric concepts that directly convert heat into electricity.The main challenge in practical applications for thermoelectrics is the high cost from both materials and manufacturing.Recently,breakthrough progresses in ionic thermoelectrics open up new possibilities to charge energy storage devices when submitted to a temperature gradient.The charging voltage is internally from the ionic Seebeck effect of the electrolyte between two electrodes.Hence electrolytes with high thermoelectric figure of merit are classified as ionic thermoelectric materials.Most ionic thermoelectric materials are composed of abundant elements,and they can generate hundreds of times larger thermal voltage than that of electronic materials.This emerging thermoelectric category brings new hope to fabricate low cost and large area heat-to-energy conversion devices,and triggers a renewed interest for ionic thermodiffusion.In this review,we summarize the state of the art in the new field of ionic thermoelectrics,from the driving force of the ionic thermodiffusion to material and application developments.We present a general map of ionic thermoelectric materials,discuss the unique characters of each type of the reported electrolytes,and propose potential optimization and future topics of ionic thermoelectrics.
基金supported by the National Natural Science Foundation of China(U2002216,52172261,51627803,51972332,22075150,and U1902218)the National Key Research and Development Program of China(2019YFE0118100)。
文摘Photo-generated carrier recombination loss at the CZTSSe/Cd S front interface is a key issue to the opencircuit voltage(V_(OC)) deficit of Cu_(2)ZnSnS_(x)Se_(4-x)(CZTSSe) solar cells. Here, by the aid of an easy-handling spin-coating method, a thin PCBM([6,6]-phenyl-C61-butyric acid methyl ester) layer as an electron extraction layer has been introduced on the top of CdS buffer layer to modify CZTSSe/CdS/ZnO-ITO(In_(2)O_(3):Sn) interfacial properties. Based on Sn^(4+)/DMSO(dimethyl sulfoxide) solution system, a totalarea efficiency of 12.87% with a VOC of 529 m V has been achieved. A comprehensive investigation on the influence of PCBM layer on carrier extraction, transportation and recombination processes has been carried out. It is found that the PCBM layer can smooth over the Cd S film roughness, thus beneficial for a dense and flat window layer. Furthermore, this CZTSSe/Cd S/PCBM heterostructure can accelerate carrier separation and extraction and block holes from the front interface as well, which is mainly ascribed to the downward band bending of the absorber and a widened space charge region. Our work provides a feasible way to improve the front interfacial property and the cell performance of CZTSSe solar cells by the aid of organic interfacial materials.
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
基金financially supported by the Natural Science Foundation of China(52277218)the Hubei Provincial Natural Science Foundation of China(2024AFA094)+1 种基金the Excellent Discipline Cultivation Project by JHUN(2023XKZ009)the Graduate Student Innovation Fund of JHUN(KYCXJJ202422).
文摘Lithium metal batteries(LMBs)with high energy density are impeded by the instability of solid electrolyte interface(SEI)and the uncontrolled growth of lithium(Li)dendrite.To mitigate these challenges,optimizing the SEI structure and Li deposition behavior is the key to stable LMBs.This study novelty proposes a facile synthesis of MgF_(2)/carbon(C)nanocomposite through the mechanochemical reaction between metallic Mg and polytetrafluoroethylene(PTFE)powders,and its modified polypropylene(PP)separator enhances LMB performance.The in-situ formed highly conductive fluorine-doped C species play a crucial role in facilitating ion/electron transport,thereby accelerating electrochemical kinetics and altering Li deposition direction.During cycling,the in-situ reaction between MgF_(2)and Li leads to the formation of LiMg alloy,along with a LiF-rich SEI layer,which reduces the nucleation overpotential and reinforces the interphase strength,leading to homogeneous Li deposition with dendrite-free feature.Benefiting from these merits,the Li metal is densely and uniformly deposited on the MgF_(2)/C@PP separator side rather than on the current collector side.Furthermore,the symmetric cell with MgF_(2)/C@PP exhibits superb Li plating/stripping performance over 2800 h at 1 mA cm^(-2)and 2 mA h cm^(-2).More importantly,the assembled Li@MgF_(2)/C@PPILiFePO4full cell with a low negative/positive ratio of 3.6delivers an impressive cyclability with 82.7%capacity retention over 1400 cycles at 1 C.
