As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fa...As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fabrication of new nanofilm in this family. Using precious metals, such as platinum and palladium, to serve as transition metals combined with chalcogen is a new approach to explore novel TMDs. Also, the proportion between transition metal and chalcogen atoms is found not only to exist in conventional form of 1 : 2. Herein, we reported a comprehensive study of a new 2D precious metal selenide, namely AuSe monolayer. Based on density functional theory, our result indicated that AuSe monolayer is a semiconductor with indirect band-gap of 2.0 eV, which possesses superior dynamic stability and thermodynamic stability with cohesive energy up to–7.87 eV/atom. Moreover, it has been confirmed that ionic bonding predominates in Au–Se bonds and absorption peaks in all directions distribute in the deep ultraviolet region. In addition, both vibration modes dominating marked Raman peaks are parallel to the 2D plane.展开更多
The possibility to induce a macroscopic magnetic moment in lead halide perovskites(LHPs),combined with their excellent optoelectronic properties,is of fundamental interest and has promising spintronic applications.How...The possibility to induce a macroscopic magnetic moment in lead halide perovskites(LHPs),combined with their excellent optoelectronic properties,is of fundamental interest and has promising spintronic applications.However,these possibilities remain an open question in both theory and experiment.Here,theoretical and experimental studies are performed to explore ferromagnetic states in LHPs originated from lattice defects.First-principle calculations reveal that shallow-level Br vacancies in defective CsPbBr3 can produce spin-splitting states and the coupling between them leads to a ferromagnetic ground state.Experimentally,ferromagnetism at 300 K is observed in room-temperature synthesized CsPbBr3 nanocrystals,but is not observed in hot-injection prepared CsPbBr3 quantum dots and in CsPbBr3 single crystals,highlighting the significance played by vacancy defects.Furthermore,the ferromagnetism in the CsPbBr3 nanocrystals can be enhanced fourfold with Ni2+ion dopants,due to enhancement of the exchange coupling between magnetic polarons.Room-temperature ferromagnetism is also observed in other LHPs,which suggests that vacancy-induced ferromagnetism may be a universal feature of solution-processed LHPs,which is useful for future spintronic devices.展开更多
Inorganic perovskites(Cs Pb X3(X=I,Br,Cl))have broad prospection in the field of high-definition displaying due to its excellent optoelectronic characteristics.The vacuum deposition process possesses advantages and co...Inorganic perovskites(Cs Pb X3(X=I,Br,Cl))have broad prospection in the field of high-definition displaying due to its excellent optoelectronic characteristics.The vacuum deposition process possesses advantages and competitiveness in the industrialized production.However,the performance of light emitting diodes(LEDs)based on vacuum-deposited is incredibly low.Herein,we proposed a heating-assisted vacuum deposition(HAVD)method to construct inorganic perovskite LEDs(Pe LEDs)with enhanced performance.The roughness and crystallinity of perovskite film were improved by regulating the heating treatment of substrates.And the perovskite film exhibited largely rise in luminescence,with decreasing defect density.Consequently,with the optimized temperature,the green Pe LEDs exhibited 100-fold improvement of external quantum efficiency(EQE)with the luminance of up to 11941 cd/m2,and the full width at half-maximum(FWHM)of the electroluminescence(EL)spectra was decreased from 25 to 17 nm.At the same time,the red and blue Pe LEDs also exhibited obvious enhancement in EQE and luminance by HAVD method,and both the FWHM of EL spectra dropped below 20 nm,exhibiting excellent high color purity.HAVD strategy has a huge potential to be a new commonly used method for low-cost fabrication of displays and lighting.展开更多
The electronic properties and transport properties of MoTe2/SnS2 heterostructure Tunneling FETs are investigated by the density functional theory coupled with non-equilibrium Green’s function method.Two dimensional(2...The electronic properties and transport properties of MoTe2/SnS2 heterostructure Tunneling FETs are investigated by the density functional theory coupled with non-equilibrium Green’s function method.Two dimensional(2D)monolayer MoTe2 and SnS2 are combined to a vertical van der Waals heterojunction.A small staggered band gap is formed in the overlap region,while larger gaps remain in the underlap source and drain regions of monolayer MoTe2 and SnS2 respectively.Such a type-II heterojunction is favorable for tunneling FET.Furthermore,we suggest short stack length and large gate-to-drain overlap to enhance the on-state current suppress the leakage current respectively.The numerical results show that at a low drain to source voltage Vds=0.05V,On/Off current ratio can reach 108 and the On-state currents is over 20μA/μm for ntype devices.Our results present that van der Waals heterostructure TFETs can be potential candidate as next generation ultra-steep subthreshold and low-power electronic applications.展开更多
Perovskite based light-emitting diodes(PeLEDs)have become a powerful candidate for next-generation solid-state lightings and high-definition displays due to their high photoluminescence quantum yield(PLQY),tunable emi...Perovskite based light-emitting diodes(PeLEDs)have become a powerful candidate for next-generation solid-state lightings and high-definition displays due to their high photoluminescence quantum yield(PLQY),tunable emission wavelength over the visible spectrum,and narrow emission linewidths.Over the past few years,the development of red-and green-emissive PeLEDs has rapidly increased,and the corresponding external quantum efficiencies(EQE)have exceeded 20%.However,the research progress of blue-emitting PeLEDs is limited by its poor material quality and inappropriate device structure.Currently,the maximum EQE of blue PeLED is only 6.2%,which is far from the industrialization requirements.In order to promote the development of blue PeLEDs,we summarize the recent research progress of blue perovskite materials and LEDs and discuss several fatal challenges,mainly embodied in low efficiency and poor stability.In order to overcome these challenges,detailed analysis and strategies are put forward in terms of the materials and devices.For the former,we summarize the feasible strategy for the preparation of efficient and stable blue-emissive perovskites using component engineering.For the latter,we analyze the advantages and limitations of the different strategies for blue-emissive perovskite in LEDs.At the end of the review,a comprehensive outlook is detailed,including future development directions and several technical problems to be solved.Thus,we aim to highlight the significance and promote the industrialization of PeLEDs.展开更多
Metal halide perovskites have generated significant attention in recent years because of their extraordinary physical properties and photovoltaic performance.Among these,inorganic perovskite quantum dots(QDs)stand out...Metal halide perovskites have generated significant attention in recent years because of their extraordinary physical properties and photovoltaic performance.Among these,inorganic perovskite quantum dots(QDs)stand out for their prominent merits,such as quantum confinement effects,high photoluminescence quantum yield,and defect-tolerant structures.Additionally,ligand engineering and an all-inorganic composition lead to a robust platform for ambient-stable QD devices.This review presents the state-of-the-art research progress on inorganic perovskite QDs,emphasizing their electronic applications.In detail,the physical properties of inorganic perovskite QDs will be introduced first,followed by a discussion of synthesis methods and growth control.Afterwards,the emerging applications of inorganic perovskite QDs in electronics,including transistors and memories,will be presented.Finally,this review will provide an outlook on potential strategies for advancing inorganic perovskite QD technologies.展开更多
The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material structure.In this study,we prepared a novel Sn S_(2)...The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material structure.In this study,we prepared a novel Sn S_(2)/black phosphorus(BP)two-dimensional(2D)-2D heterostructure via the in situ hydrothermal growth of Sn S_(2)nanosheets on exfoliated BP lamellae for NO_(2)sensing applications.In the Sn S_(2)/BP composite,the holes with high oxidizability in p-type BP could oxidize Sn^(2+)into Sn^(4+),thus inhibiting the formation of Lewis acidic S vacancies.This Sn^(2+)/Lewis acidity suppression of the composite was further confirmed by X-ray photoelectron spectroscopy and acidic double-layer capacitance analyses,and promoted the adsorption and detection of acidic NO_(2).Owing to its valence and Lewis acidity engineering,the Sn S_(2)/BP heterostructure sensor could detect trace levels of NO_(2)as low as 100 ppb(parts per billion)with high response,fast response/recovery,good stability,and selectivity at room temperature.The high absorption energy of NO_(2)(à0.74 e V),as indicated by the density functional theory calculations,suggests that NO_(2)was chemically adsorbed on the Sn S_(2)/BP surface,which was also evidenced by the in situ Raman spectroscopy results.This work opens up interesting opportunities for the rational design of highly efficient NO_(2)gas sensors through Lewis acidity modification and interface engineering.展开更多
White light-emitting diodes(WLEDs),as key infrastructure,play an important role in the field of lighting and display.In the past few decades,many methods were developed to prepare WLEDs.A common strategy is to use blu...White light-emitting diodes(WLEDs),as key infrastructure,play an important role in the field of lighting and display.In the past few decades,many methods were developed to prepare WLEDs.A common strategy is to use blue LEDs to excite yttrium aluminum garnet(YAG)phosphors and generate composite white light,which is now the main technology for commercial lighting.In 2014,Nobel Prize in Physics was awarded to Nakamura et al.for their contribution to blue LEDs[1,2].展开更多
The use of renewable sources such as solar,ocean,geothermal,and wind energy to drive water electrolysis reactions to obtain green and clean hydrogen fuels is one of the important paths to achieve sustainable energy de...The use of renewable sources such as solar,ocean,geothermal,and wind energy to drive water electrolysis reactions to obtain green and clean hydrogen fuels is one of the important paths to achieve sustainable energy development.At present,most water electrolysis technologies need to conduct corresponding pre-processing,such as diluting water sources and purifying dehydration,which will greatly increase operating costs.The development of direct seawater electrolytic process can effectively solve the above problems.Here,we review the latest progress of the electrode materials and catalysts of the direct electrolysis process of seawater,and discuss how to design high activity and high-selective electrode materials for water electrolysis with familiar impurities (such as chloride,metal ions and biological organisms) existing in the future.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
Herein, a bidirectional polarization strategy is proposed for hosting efficient and durable lithium-sulfur battery(Li-S) electrochemistry. By co-doping electronegative N and electropositive B in graphene matrix(BNrGO)...Herein, a bidirectional polarization strategy is proposed for hosting efficient and durable lithium-sulfur battery(Li-S) electrochemistry. By co-doping electronegative N and electropositive B in graphene matrix(BNrGO), the bidirectional electron redistribution enables a higher polysulfide affinity over its monodoped counterparts, contributing to strong sulfur immobilization and fast conversion kinetics. As a result,BNrGO as the cathode host matrix realizes excellent cycling stability over 1000 cycles with a minimum capacity fading of 0.027% per cycle, and superb rate capability up to 10 C. Meanwhile, decent areal capacity(6.46 m Ah/cm^(2)) and cyclability(300 cycles) are also achievable under high sulfur loading and limited electrolyte. This work provides instructive insights into the interaction between doping engineering and sulfur electrochemistry for pursuing superior Li-S batteries.展开更多
A novel dimesityl-decorated bistetracene derivative 8,16-dimesityltetraceno[2,1,12,11-opqra]tetracene（DMTA） has been synthesized and characterized. Its single crystal analysis demonstrates that the parent bistetrace...A novel dimesityl-decorated bistetracene derivative 8,16-dimesityltetraceno[2,1,12,11-opqra]tetracene（DMTA） has been synthesized and characterized. Its single crystal analysis demonstrates that the parent bistetracene backbone is almost in a plane without any intermolecular 7 r-stacking interaction. DMTA exhibited the low-energy absorption at 560/607 nm and emission spectra at 617/663 nm, respectively.The fabricated device based on DMTA doping into 2,6-bis（3-（9 H-carbazol-9-yl）phenyl）pyridine（1 %） as an emitter present a maximum brightness of 632 cd/m^2 at 14.7 V with the CIE coordinate of（0.623,0.349）.展开更多
Owing to the large exciton binding energy(>100 meV)of most organic materials,the process of exciton dissociation into free electrons and holes is seriously hindered,which plays a key role in the photocatalytic syst...Owing to the large exciton binding energy(>100 meV)of most organic materials,the process of exciton dissociation into free electrons and holes is seriously hindered,which plays a key role in the photocatalytic system.In this study,a series of chalcogen(S,Se)-substituted mesoporous covalent organic frameworks(COFs)have been synthesized for enhanced photocatalytic organic transformations.Photoelectrochemical measurements indicate that the introduction of semi-metallic Se atom and the enlargement of conjugation degree can not only reduce the exciton binding energy accelerating the charge separation,but also reduce the band gap of COFs.As a result,the COF-NUST-36 with the lowest exciton binding energy(39.5 meV)shows the highest photocatalytic performance for selective oxidation of amines(up to 98%Conv.and 97.5%Sel.).This work provides a feasible method for designing COFs with high photocatalytic activity by adjusting exciton binding energy.展开更多
Inkjet-printed quantum dot light-emitting diodes(QLEDs)are emerging as a promising technology for next-generation displays.However,the progress in fabricating QLEDs using inkjet printing technique has been slower comp...Inkjet-printed quantum dot light-emitting diodes(QLEDs)are emerging as a promising technology for next-generation displays.However,the progress in fabricating QLEDs using inkjet printing technique has been slower compared to spin-coated devices,particularly in terms of efficiency and stability.The key to achieving high performance QLEDs lies in creating a highly ordered and uniform inkjet-printed quantum dot(QD)thin film.In this study,we present a highly effective strategy to significantly improve the quality of inkjet-printed CdZnSe/CdZnS/ZnS QD thin films through a pressure-assisted thermal annealing(PTA)approach.Benefiting from this PTA process,a high quality QD thin film with ordered packing,low surface roughness,high photoluminescence and excellent electrical property is obtained.The mechanism behind the PTA process and its profound impact on device performance have been thoroughly investigated and understood.Consequently,a record high external quantum efficiency(EQE)of 23.08%with an impressive operational lifetime(T50)of up to 343,342h@100cdm−2,and a record EQE of 22.43%with T50 exceeding to 1,500,463h@100cdm−2 are achieved in inkjet-printed red and green CdZnSe-based QLEDs,respectively.This work highlights the PTA process as an important approach to realize highly efficient and stable inkjet-printed QLEDs,thus advancing QLED technology to practical applications.展开更多
Perovskite quantum-dot-based light-emitting diodes(QLEDs)are highly promising for future solid-state lightings and high-definition displays due to their excellent color purity.However,their device performance is easil...Perovskite quantum-dot-based light-emitting diodes(QLEDs)are highly promising for future solid-state lightings and high-definition displays due to their excellent color purity.However,their device performance is easily affected by charge accumulation induced luminescence quenching due to imbalanced charge injection in the devices.Here we report green perovskite QLEDs with simultaneously improved efficiency and operational lifetime through balancing the charge injection with the employment of a bilayered electron transport structure.The charge-balanced QLEDs exhibit a color-saturated green emission with a full-width at half-maximum(FWHM)of 18 nm and a peak at 520 nm,a low turn-on voltage of2.0 V and a champion external quantum efficiency(EQE)of 21.63%,representing one of the most efficient perovskite QLEDs so far.In addition,the devices with modulated charge balance demonstrate a nearly 20-fold improvement in the operational lifetime compared to the control device.Our results demonstrate the great potential of further improving the device performance of perovskite QLEDs toward practical applications in lightings and displays via rational device engineering.展开更多
Voltage loading-induced change in the electroluminescence(EL)wavelength of mixed halide perovskite light-emitting diodes(PeLEDs),so-called color-shift,has become an inevitable phenomenon,which is seriously unfavorable...Voltage loading-induced change in the electroluminescence(EL)wavelength of mixed halide perovskite light-emitting diodes(PeLEDs),so-called color-shift,has become an inevitable phenomenon,which is seriously unfavorable to their applications in lighting and display.Here,we achieve color-stable blue PeLEDs via a hydrogen-bonded amine-group doping strategy.Selecting guanidine(GA)or formamidinium(FA)as amine-group(-NH_(2))doping source for CsPbBr_(x)Cl_(3-x)quantum dots(QDs),experimental and theoretical results reveal that the strong N-H…X(X=Br/Cl)bonding can be produced between-NH_(2)dopants and Pb-X lattices,thereby increasing the migration barrier of halide anions.Resultantly,color-stable sky-blue devices were realized with emission peaks fixed at 490.5(GA)and 492.5(FA)nm without any obvious shift as the voltage increases,in sharp contrast devices without N-H…X producing a 15 nm red-shift from 487 to 502 nm.Not only that,maximum external quantum efficiency is improved to 3.02%and 4.14%from the initial 1.3%.This finding offers a convenient boulevard to achieve color-stable PeLEDs with high efficiency.展开更多
Full-spectrum underwater optical communication(UOC)is of great significance for major strategic needs including resource development,scientific exploration,and homeland security.As the core of the full-spectrum UOC sy...Full-spectrum underwater optical communication(UOC)is of great significance for major strategic needs including resource development,scientific exploration,and homeland security.As the core of the full-spectrum UOC system,photodetectors(PDs)are plagued by stringent requirements including a broadband response,intrinsic water resistance,and a high detectivity.In this work,two-dimensional(2D)halide perovskites(HPs)and corresponding PDs are constructed by stearamine(SA),representing the rarely explored long-chain aliphatic amine series,to own waterproofness,ultralow noise,and superior optoelectronic performance,which consequently enable a high suitability for UOC.By dimensionality and composition modulations to extend the absorption onset down to 1.5 eV,a broadband response covering the entire transmission window of water(>1.55 eV)for full-spectrum UOC can be obtained.Besides,featuring a high responsivity of 3.27 A·W^(-1),a peak external quantum efficiency(EQE)of 630%,fast rise/decay times of 0.35 ms/0.54 ms,a superior detectivity up to 1.35×10^(12)Jones and the capability to distinguish various waveforms and light intensities,the PDs present sensitive and persistent photoresponse underwater.As a result,proof-of-concept wireless transmission of ASCII codes in water is demonstrated.展开更多
Carbon neutrality,energy savings,and lighting costs and quality have always led to urgent demand for lighting technology innovation.White light-emitting diodes(WLEDs)based on a single emissive layer(SEL)fabricated by ...Carbon neutrality,energy savings,and lighting costs and quality have always led to urgent demand for lighting technology innovation.White light-emitting diodes(WLEDs)based on a single emissive layer(SEL)fabricated by the solution method have been continuously researched in recent years;they are advantageous because they have a low cost and are ultrathin and flexible.Here,we reviewed the history and development of SEL-WLEDs over recent years to provide inspiration and promote their progress in lighting applications.We first introduced the emitters and analysed the advantages of these emitters in creating SEL-WLEDs and then reviewed some cases that involve the above emitters,which were formed via vacuum thermal evaporation or solution processes.Some notable developments that deserve attention are highlighted in this review due to their potential use in SEL-WLEDs,such as perovskite materials.Finally,we looked at future development trends of SEL-WLEDs and proposed potential research directions.展开更多
Semiconductor quantum dots(SQDs)have received much attention due to their high quantum yield(QY),tunable emission spectrum,and excellent photostability.These unique optical properties endow SQDs with excellent biomedi...Semiconductor quantum dots(SQDs)have received much attention due to their high quantum yield(QY),tunable emission spectrum,and excellent photostability.These unique optical properties endow SQDs with excellent biomedical application prospects,including biomedical imaging,drug delivery,clinical diagnosis,photodynamic therapy,DNA hybridization,and RNA profiling.This review introduces the classification of QDs and provides a brief description of the characteristics of QDs under each classification.Taking the type II B-VI A QDs as an example,inorganic and organic modification methods,and the corresponding advantages and disadvantages are summarized and discussed.Controlled modification approaches make them exhibit different functions in the bioimaging and drug delivery fields.The typical or classic instances are also listed to present the highlights of the applications of SQDs in the biomedical field.Based on these,this review raises a variety of possible challenges and perspectives of SQDs in biomedical applications in the future.展开更多
Quantum confinement effect（QCE）, an essential physical phenomenon of semiconductors when the size becomes comparable to the exciton Bohr radius, typically results in quite different physical properties of low-dimens...Quantum confinement effect（QCE）, an essential physical phenomenon of semiconductors when the size becomes comparable to the exciton Bohr radius, typically results in quite different physical properties of low-dimensional materials from their bulk counterparts and can be exploited to enhance the device performance in various optoelectronic applications. Here, taking Cs Pb Br3 as an example, we reported QCE in all-inorganic halide perovskite in two-dimensional（2D） nanoplates. Blue shifts in optical absorption and photoluminescence spectra were found to be stronger in thinner nanoplates than that in thicker nanoplates, whose thickness lowered below -7 nm. The exciton binding energy results showed similar trend as that obtained for the optical absorption and photoluminescence. Meanwile, the function of integrated intensity and full width at half maximum and temperature also showed similar results, further supporting our conclusions. The results displayed the QCE in all-inorganic halide perovskite nanoplates and helped to design the all-inorganic halide perovskites with desired optical properties.展开更多
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20180071)the Fundamental Research Funds for the Central Universities(No.30919011109)PAPD of Jiangsu Higher Education Institutions
文摘As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fabrication of new nanofilm in this family. Using precious metals, such as platinum and palladium, to serve as transition metals combined with chalcogen is a new approach to explore novel TMDs. Also, the proportion between transition metal and chalcogen atoms is found not only to exist in conventional form of 1 : 2. Herein, we reported a comprehensive study of a new 2D precious metal selenide, namely AuSe monolayer. Based on density functional theory, our result indicated that AuSe monolayer is a semiconductor with indirect band-gap of 2.0 eV, which possesses superior dynamic stability and thermodynamic stability with cohesive energy up to–7.87 eV/atom. Moreover, it has been confirmed that ionic bonding predominates in Au–Se bonds and absorption peaks in all directions distribute in the deep ultraviolet region. In addition, both vibration modes dominating marked Raman peaks are parallel to the 2D plane.
基金This work was financially supported by NSFC(61725402)the Natural Science Foundation of Jiangsu Province(BK20190475).
文摘The possibility to induce a macroscopic magnetic moment in lead halide perovskites(LHPs),combined with their excellent optoelectronic properties,is of fundamental interest and has promising spintronic applications.However,these possibilities remain an open question in both theory and experiment.Here,theoretical and experimental studies are performed to explore ferromagnetic states in LHPs originated from lattice defects.First-principle calculations reveal that shallow-level Br vacancies in defective CsPbBr3 can produce spin-splitting states and the coupling between them leads to a ferromagnetic ground state.Experimentally,ferromagnetism at 300 K is observed in room-temperature synthesized CsPbBr3 nanocrystals,but is not observed in hot-injection prepared CsPbBr3 quantum dots and in CsPbBr3 single crystals,highlighting the significance played by vacancy defects.Furthermore,the ferromagnetism in the CsPbBr3 nanocrystals can be enhanced fourfold with Ni2+ion dopants,due to enhancement of the exchange coupling between magnetic polarons.Room-temperature ferromagnetism is also observed in other LHPs,which suggests that vacancy-induced ferromagnetism may be a universal feature of solution-processed LHPs,which is useful for future spintronic devices.
基金financially supported by NSFC(51922049,61604074)the National Key Research and Development Program of China(2016YFB0401701)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20180020)PAPD of Jiangsu Higher Education Institutions.
文摘Inorganic perovskites(Cs Pb X3(X=I,Br,Cl))have broad prospection in the field of high-definition displaying due to its excellent optoelectronic characteristics.The vacuum deposition process possesses advantages and competitiveness in the industrialized production.However,the performance of light emitting diodes(LEDs)based on vacuum-deposited is incredibly low.Herein,we proposed a heating-assisted vacuum deposition(HAVD)method to construct inorganic perovskite LEDs(Pe LEDs)with enhanced performance.The roughness and crystallinity of perovskite film were improved by regulating the heating treatment of substrates.And the perovskite film exhibited largely rise in luminescence,with decreasing defect density.Consequently,with the optimized temperature,the green Pe LEDs exhibited 100-fold improvement of external quantum efficiency(EQE)with the luminance of up to 11941 cd/m2,and the full width at half-maximum(FWHM)of the electroluminescence(EL)spectra was decreased from 25 to 17 nm.At the same time,the red and blue Pe LEDs also exhibited obvious enhancement in EQE and luminance by HAVD method,and both the FWHM of EL spectra dropped below 20 nm,exhibiting excellent high color purity.HAVD strategy has a huge potential to be a new commonly used method for low-cost fabrication of displays and lighting.
基金the Training Program of the Major Research Plan of the National Natural Science Foundation of China(61774168,91964103)and the MOST(2016YFA0202300).
文摘The electronic properties and transport properties of MoTe2/SnS2 heterostructure Tunneling FETs are investigated by the density functional theory coupled with non-equilibrium Green’s function method.Two dimensional(2D)monolayer MoTe2 and SnS2 are combined to a vertical van der Waals heterojunction.A small staggered band gap is formed in the overlap region,while larger gaps remain in the underlap source and drain regions of monolayer MoTe2 and SnS2 respectively.Such a type-II heterojunction is favorable for tunneling FET.Furthermore,we suggest short stack length and large gate-to-drain overlap to enhance the on-state current suppress the leakage current respectively.The numerical results show that at a low drain to source voltage Vds=0.05V,On/Off current ratio can reach 108 and the On-state currents is over 20μA/μm for ntype devices.Our results present that van der Waals heterostructure TFETs can be potential candidate as next generation ultra-steep subthreshold and low-power electronic applications.
基金supported by NSFC(61604074,61725402)the National Key Research and Development Program of China(2016YFB0401701)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20180020,BK20160827)the Fundamental Research Funds for the Central Universities(No.30917011202)PAPD of Jiangsu Higher Education Institutions,and large instrument equipment open fund of Nanjing University of Science and Technology.
文摘Perovskite based light-emitting diodes(PeLEDs)have become a powerful candidate for next-generation solid-state lightings and high-definition displays due to their high photoluminescence quantum yield(PLQY),tunable emission wavelength over the visible spectrum,and narrow emission linewidths.Over the past few years,the development of red-and green-emissive PeLEDs has rapidly increased,and the corresponding external quantum efficiencies(EQE)have exceeded 20%.However,the research progress of blue-emitting PeLEDs is limited by its poor material quality and inappropriate device structure.Currently,the maximum EQE of blue PeLED is only 6.2%,which is far from the industrialization requirements.In order to promote the development of blue PeLEDs,we summarize the recent research progress of blue perovskite materials and LEDs and discuss several fatal challenges,mainly embodied in low efficiency and poor stability.In order to overcome these challenges,detailed analysis and strategies are put forward in terms of the materials and devices.For the former,we summarize the feasible strategy for the preparation of efficient and stable blue-emissive perovskites using component engineering.For the latter,we analyze the advantages and limitations of the different strategies for blue-emissive perovskite in LEDs.At the end of the review,a comprehensive outlook is detailed,including future development directions and several technical problems to be solved.Thus,we aim to highlight the significance and promote the industrialization of PeLEDs.
基金The authors thank the support from the Australian Research Council(DP190103316)UNSW SHARP Project(RG163043).
文摘Metal halide perovskites have generated significant attention in recent years because of their extraordinary physical properties and photovoltaic performance.Among these,inorganic perovskite quantum dots(QDs)stand out for their prominent merits,such as quantum confinement effects,high photoluminescence quantum yield,and defect-tolerant structures.Additionally,ligand engineering and an all-inorganic composition lead to a robust platform for ambient-stable QD devices.This review presents the state-of-the-art research progress on inorganic perovskite QDs,emphasizing their electronic applications.In detail,the physical properties of inorganic perovskite QDs will be introduced first,followed by a discussion of synthesis methods and growth control.Afterwards,the emerging applications of inorganic perovskite QDs in electronics,including transistors and memories,will be presented.Finally,this review will provide an outlook on potential strategies for advancing inorganic perovskite QD technologies.
基金supported by the National Natural Science Foundation of China(51802252)Natural Science Foundation of Shaanxi Province(2020JM-032)+1 种基金Natural Science Foundation of Jiangsu Province(BK20180237)111 Project 2.0(BP0618008)。
文摘The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material structure.In this study,we prepared a novel Sn S_(2)/black phosphorus(BP)two-dimensional(2D)-2D heterostructure via the in situ hydrothermal growth of Sn S_(2)nanosheets on exfoliated BP lamellae for NO_(2)sensing applications.In the Sn S_(2)/BP composite,the holes with high oxidizability in p-type BP could oxidize Sn^(2+)into Sn^(4+),thus inhibiting the formation of Lewis acidic S vacancies.This Sn^(2+)/Lewis acidity suppression of the composite was further confirmed by X-ray photoelectron spectroscopy and acidic double-layer capacitance analyses,and promoted the adsorption and detection of acidic NO_(2).Owing to its valence and Lewis acidity engineering,the Sn S_(2)/BP heterostructure sensor could detect trace levels of NO_(2)as low as 100 ppb(parts per billion)with high response,fast response/recovery,good stability,and selectivity at room temperature.The high absorption energy of NO_(2)(à0.74 e V),as indicated by the density functional theory calculations,suggests that NO_(2)was chemically adsorbed on the Sn S_(2)/BP surface,which was also evidenced by the in situ Raman spectroscopy results.This work opens up interesting opportunities for the rational design of highly efficient NO_(2)gas sensors through Lewis acidity modification and interface engineering.
基金H.Zeng thanks National Natural Science Foundation of China(61725402,62004101)the Fundamental Research Funds for the Central Universities(30919012107,30920041117)+4 种基金"Ten Thousand Talents Plan"(W03020394)the Six Top Talent Innovation Teams of Jiangsu Province(TDXCL-004)the China Postdoctoral Science Foundation(2020M681600)the Postdoctoral Research Funding Scheme of Jiangsu Province(2020Z124)for financial support.L.Ding thanks 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White light-emitting diodes(WLEDs),as key infrastructure,play an important role in the field of lighting and display.In the past few decades,many methods were developed to prepare WLEDs.A common strategy is to use blue LEDs to excite yttrium aluminum garnet(YAG)phosphors and generate composite white light,which is now the main technology for commercial lighting.In 2014,Nobel Prize in Physics was awarded to Nakamura et al.for their contribution to blue LEDs[1,2].
基金financially supported by the National Nature Science Foundation of China(Nos.52201281 and 22172077).
文摘The use of renewable sources such as solar,ocean,geothermal,and wind energy to drive water electrolysis reactions to obtain green and clean hydrogen fuels is one of the important paths to achieve sustainable energy development.At present,most water electrolysis technologies need to conduct corresponding pre-processing,such as diluting water sources and purifying dehydration,which will greatly increase operating costs.The development of direct seawater electrolytic process can effectively solve the above problems.Here,we review the latest progress of the electrode materials and catalysts of the direct electrolysis process of seawater,and discuss how to design high activity and high-selective electrode materials for water electrolysis with familiar impurities (such as chloride,metal ions and biological organisms) existing in the future.
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 National Natural Science Foundation of China (No. 22109072)the Natural Science Foundation of Jiangsu Province (No. BK20210349)+2 种基金the China Postdoctoral Science Foundation (No. 2021M691586)the Postdoctoral Research Funding Scheme of Jiangsu Province (No. 2021K446C)the Shuangchuang (Mass Innovation and Entrepreneurship) Program of Jiangsu Province (No. JSSCBS20210208)。
文摘Herein, a bidirectional polarization strategy is proposed for hosting efficient and durable lithium-sulfur battery(Li-S) electrochemistry. By co-doping electronegative N and electropositive B in graphene matrix(BNrGO), the bidirectional electron redistribution enables a higher polysulfide affinity over its monodoped counterparts, contributing to strong sulfur immobilization and fast conversion kinetics. As a result,BNrGO as the cathode host matrix realizes excellent cycling stability over 1000 cycles with a minimum capacity fading of 0.027% per cycle, and superb rate capability up to 10 C. Meanwhile, decent areal capacity(6.46 m Ah/cm^(2)) and cyclability(300 cycles) are also achievable under high sulfur loading and limited electrolyte. This work provides instructive insights into the interaction between doping engineering and sulfur electrochemistry for pursuing superior Li-S batteries.
基金financially supported by the National Natural Science Foundation of China(Nos. 21102031, 21442010 and 21672051)the Natural Science Foundation of Hebei Province for Distinguished Young Scholar(No. B2017201072)+1 种基金Cultivation Project (No. B2015201183)the Natural Science Foundation of Hebei University (No. 2015JQY02)
文摘A novel dimesityl-decorated bistetracene derivative 8,16-dimesityltetraceno[2,1,12,11-opqra]tetracene（DMTA） has been synthesized and characterized. Its single crystal analysis demonstrates that the parent bistetracene backbone is almost in a plane without any intermolecular 7 r-stacking interaction. DMTA exhibited the low-energy absorption at 560/607 nm and emission spectra at 617/663 nm, respectively.The fabricated device based on DMTA doping into 2,6-bis（3-（9 H-carbazol-9-yl）phenyl）pyridine（1 %） as an emitter present a maximum brightness of 632 cd/m^2 at 14.7 V with the CIE coordinate of（0.623,0.349）.
基金financially supported by the National Natural Science Foundation of China(No.22171136)the Natural Science Foundation of Jiangsu Province(Nos.BK20220928,BK20220079)+4 种基金the Fundamental Research Funds for the Central Universities(Nos.30921011102,30922010902)the Medical Innovation and Development Project of Lanzhou University(No.lzuyxcx-2022-156)CAMS Innovation Fund for Medical Sciences(CIFMS,Nos.2019-I2M-5-074,2021-I2M-1-026,2021-I2M-3-001)the Startup Funding from Nanjing University of Science and Technology(Nos.AE89990,AE89991/376)G.Zhang acknowledges the support of the Thousand Young Talent Plan.
文摘Owing to the large exciton binding energy(>100 meV)of most organic materials,the process of exciton dissociation into free electrons and holes is seriously hindered,which plays a key role in the photocatalytic system.In this study,a series of chalcogen(S,Se)-substituted mesoporous covalent organic frameworks(COFs)have been synthesized for enhanced photocatalytic organic transformations.Photoelectrochemical measurements indicate that the introduction of semi-metallic Se atom and the enlargement of conjugation degree can not only reduce the exciton binding energy accelerating the charge separation,but also reduce the band gap of COFs.As a result,the COF-NUST-36 with the lowest exciton binding energy(39.5 meV)shows the highest photocatalytic performance for selective oxidation of amines(up to 98%Conv.and 97.5%Sel.).This work provides a feasible method for designing COFs with high photocatalytic activity by adjusting exciton binding energy.
基金This work was supported by NSFC(Nos.62261160392,52131304,61725402,U1605244,22279059)the Fundamental Research Funds for the Central Universities(Nos.30921011106,30919012107)+3 种基金the Research Innovation Program of Nanjing Overseas Returnees(No.AD411025)the start-up funding from the Nanjing University of Science and Technology,the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2023ZB844)the China Postdoctoral Science Foundation(No.2023M731687)The authors are also thankful for the support from the NJUST large instrument equipment open fund and Vacuum Interconnect Nano X Research Facility(NANO-X)of Suzhou Institute of Nano-Tech and Nano-Bionics,CAS.
文摘Inkjet-printed quantum dot light-emitting diodes(QLEDs)are emerging as a promising technology for next-generation displays.However,the progress in fabricating QLEDs using inkjet printing technique has been slower compared to spin-coated devices,particularly in terms of efficiency and stability.The key to achieving high performance QLEDs lies in creating a highly ordered and uniform inkjet-printed quantum dot(QD)thin film.In this study,we present a highly effective strategy to significantly improve the quality of inkjet-printed CdZnSe/CdZnS/ZnS QD thin films through a pressure-assisted thermal annealing(PTA)approach.Benefiting from this PTA process,a high quality QD thin film with ordered packing,low surface roughness,high photoluminescence and excellent electrical property is obtained.The mechanism behind the PTA process and its profound impact on device performance have been thoroughly investigated and understood.Consequently,a record high external quantum efficiency(EQE)of 23.08%with an impressive operational lifetime(T50)of up to 343,342h@100cdm−2,and a record EQE of 22.43%with T50 exceeding to 1,500,463h@100cdm−2 are achieved in inkjet-printed red and green CdZnSe-based QLEDs,respectively.This work highlights the PTA process as an important approach to realize highly efficient and stable inkjet-printed QLEDs,thus advancing QLED technology to practical applications.
基金supported by the National Natural Science Foundation of China (51922049, 61604074)the National Key Research and Development Program of China (2016YFB0401701)+2 种基金the Natural Science Foundation of Jiangsu Province (BK20180020)the Fundamental Research Funds for the Central Universities (30920032102)PAPD of Jiangsu Higher Education Institutions
文摘Perovskite quantum-dot-based light-emitting diodes(QLEDs)are highly promising for future solid-state lightings and high-definition displays due to their excellent color purity.However,their device performance is easily affected by charge accumulation induced luminescence quenching due to imbalanced charge injection in the devices.Here we report green perovskite QLEDs with simultaneously improved efficiency and operational lifetime through balancing the charge injection with the employment of a bilayered electron transport structure.The charge-balanced QLEDs exhibit a color-saturated green emission with a full-width at half-maximum(FWHM)of 18 nm and a peak at 520 nm,a low turn-on voltage of2.0 V and a champion external quantum efficiency(EQE)of 21.63%,representing one of the most efficient perovskite QLEDs so far.In addition,the devices with modulated charge balance demonstrate a nearly 20-fold improvement in the operational lifetime compared to the control device.Our results demonstrate the great potential of further improving the device performance of perovskite QLEDs toward practical applications in lightings and displays via rational device engineering.
基金the National Natural Science Foundation of China(61725402,51922049)the Fundamental Research Funds for the Central Universities(30919012107,30920032102)+2 种基金the National“Ten Thousand Talents Plan”Leading Talents(W03020394)the Six Top Talent Innovation Teams of Jiangsu Province(TD-XCL-004)the Natural Science Foundation of Jiangsu Province(BK2018002)。
文摘Voltage loading-induced change in the electroluminescence(EL)wavelength of mixed halide perovskite light-emitting diodes(PeLEDs),so-called color-shift,has become an inevitable phenomenon,which is seriously unfavorable to their applications in lighting and display.Here,we achieve color-stable blue PeLEDs via a hydrogen-bonded amine-group doping strategy.Selecting guanidine(GA)or formamidinium(FA)as amine-group(-NH_(2))doping source for CsPbBr_(x)Cl_(3-x)quantum dots(QDs),experimental and theoretical results reveal that the strong N-H…X(X=Br/Cl)bonding can be produced between-NH_(2)dopants and Pb-X lattices,thereby increasing the migration barrier of halide anions.Resultantly,color-stable sky-blue devices were realized with emission peaks fixed at 490.5(GA)and 492.5(FA)nm without any obvious shift as the voltage increases,in sharp contrast devices without N-H…X producing a 15 nm red-shift from 487 to 502 nm.Not only that,maximum external quantum efficiency is improved to 3.02%and 4.14%from the initial 1.3%.This finding offers a convenient boulevard to achieve color-stable PeLEDs with high efficiency.
基金the Natural Science Foundation of Jiangsu Province(Nos.BK20190443,BK20160815)Young Elite Scientists Sponsorship Program by Jiangsu CAST(No.JS19TJGC132574)+3 种基金2019 Overseas Students Science and Technology Innovation Project Selection Funding o f Nanjing,Fundam ental Research Funds for the Central Universities(Nos.30919011298,30919011299,30919012107)the National Key R&D Program of China(No.2017YFA0305500)the National Natural Science Foundation of China(Nos.61725402,11604152,51672132)the Six top talent innovation teams of Jiangsu Province(No.TD-XCL-004).
文摘Full-spectrum underwater optical communication(UOC)is of great significance for major strategic needs including resource development,scientific exploration,and homeland security.As the core of the full-spectrum UOC system,photodetectors(PDs)are plagued by stringent requirements including a broadband response,intrinsic water resistance,and a high detectivity.In this work,two-dimensional(2D)halide perovskites(HPs)and corresponding PDs are constructed by stearamine(SA),representing the rarely explored long-chain aliphatic amine series,to own waterproofness,ultralow noise,and superior optoelectronic performance,which consequently enable a high suitability for UOC.By dimensionality and composition modulations to extend the absorption onset down to 1.5 eV,a broadband response covering the entire transmission window of water(>1.55 eV)for full-spectrum UOC can be obtained.Besides,featuring a high responsivity of 3.27 A·W^(-1),a peak external quantum efficiency(EQE)of 630%,fast rise/decay times of 0.35 ms/0.54 ms,a superior detectivity up to 1.35×10^(12)Jones and the capability to distinguish various waveforms and light intensities,the PDs present sensitive and persistent photoresponse underwater.As a result,proof-of-concept wireless transmission of ASCII codes in water is demonstrated.
基金This research was supported by the National Natural Science Foundation of China(61725402,62004101)the Fundamental Research Funds for the Central Universities(30919012107,30920041117)+3 种基金“Ten Thousand Talents Plan”(W03020394)the Six Top Talent Innovation Teams of Jiangsu Province(TDXCL-004)the China Postdoctoral Science Foundation(2020M681600)the Postdoctoral Research Funding Scheme of Jiangsu Province(2020Z124)for financial support.
文摘Carbon neutrality,energy savings,and lighting costs and quality have always led to urgent demand for lighting technology innovation.White light-emitting diodes(WLEDs)based on a single emissive layer(SEL)fabricated by the solution method have been continuously researched in recent years;they are advantageous because they have a low cost and are ultrathin and flexible.Here,we reviewed the history and development of SEL-WLEDs over recent years to provide inspiration and promote their progress in lighting applications.We first introduced the emitters and analysed the advantages of these emitters in creating SEL-WLEDs and then reviewed some cases that involve the above emitters,which were formed via vacuum thermal evaporation or solution processes.Some notable developments that deserve attention are highlighted in this review due to their potential use in SEL-WLEDs,such as perovskite materials.Finally,we looked at future development trends of SEL-WLEDs and proposed potential research directions.
基金supported by the National Natural Science Foundation of China(61875138,61435010 and 6181101252)the Science and Technology Innovation Commission of Shenzhen(KQTD2015032416270385,JCYJ20150625103619275 and JCYJ20170811093453105)+1 种基金China Postdoctoral Science Foundation(2019M663062)the support from the Instrumental Analysis Center of Shenzhen University(Xili Campus)。
文摘Semiconductor quantum dots(SQDs)have received much attention due to their high quantum yield(QY),tunable emission spectrum,and excellent photostability.These unique optical properties endow SQDs with excellent biomedical application prospects,including biomedical imaging,drug delivery,clinical diagnosis,photodynamic therapy,DNA hybridization,and RNA profiling.This review introduces the classification of QDs and provides a brief description of the characteristics of QDs under each classification.Taking the type II B-VI A QDs as an example,inorganic and organic modification methods,and the corresponding advantages and disadvantages are summarized and discussed.Controlled modification approaches make them exhibit different functions in the bioimaging and drug delivery fields.The typical or classic instances are also listed to present the highlights of the applications of SQDs in the biomedical field.Based on these,this review raises a variety of possible challenges and perspectives of SQDs in biomedical applications in the future.
基金supported by the National Basic Research Program of China (2014CB931702)the National Key Research and Development Program of China (2016YFB0401701)+5 种基金the National Natural Science Foundation of China (NSFC 51572128 and 21403109)NSFC-RGC (5151101197)the Natural Science Foundation of Jiangsu Province (BK20160827)China Postdoctoral Science Foundation (2016M590455)the Fundamental Research Funds for the Central Universities (30915012205 and 30916015106)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Quantum confinement effect（QCE）, an essential physical phenomenon of semiconductors when the size becomes comparable to the exciton Bohr radius, typically results in quite different physical properties of low-dimensional materials from their bulk counterparts and can be exploited to enhance the device performance in various optoelectronic applications. Here, taking Cs Pb Br3 as an example, we reported QCE in all-inorganic halide perovskite in two-dimensional（2D） nanoplates. Blue shifts in optical absorption and photoluminescence spectra were found to be stronger in thinner nanoplates than that in thicker nanoplates, whose thickness lowered below -7 nm. The exciton binding energy results showed similar trend as that obtained for the optical absorption and photoluminescence. Meanwile, the function of integrated intensity and full width at half maximum and temperature also showed similar results, further supporting our conclusions. The results displayed the QCE in all-inorganic halide perovskite nanoplates and helped to design the all-inorganic halide perovskites with desired optical properties.
