Inorganic cesium metal halide perovskites have gained research interest as absorbers in perovskite solar cells due to their superior thermal stability.Among these,CsPbI2Br,with a narrower band gap than CsPbBr3 and a b...Inorganic cesium metal halide perovskites have gained research interest as absorbers in perovskite solar cells due to their superior thermal stability.Among these,CsPbI2Br,with a narrower band gap than CsPbBr3 and a better phase stability than CsPbI3,has received tremendous interest of the researchers.However,CsPbI2 Br takes adverse phase transfer easily with an exposure to the water vapor in ambient air which not only brings inconvenience for researches but also puts forward very high requirement for encapsulation.Herein,a dense and uniform film is obtained by incorporating hydrophobic CH3NH3Cl(MACl)into the precursor solution.Being attributed to a good passivation effect,the defect density is decreased from3.12×1016 to 1.49×1016 cm-3 and the average photoluminescence lifetime is increased from 8.84 to 20.6 ns.The photovoltaic device achieves a high open-circuit voltage of 1.22 V based on optimized MACl-doped film and accordingly a higher power conversion efficiency(PCE) of 12.9% which is 21.7% higher than the pristine CsPbI2Br device with PCE of 10.6%.In addition,the ambient stability of MACl-doped device has been enhanced,which is greatly attributed to the hydrophobic properties of MACl.This work provides a clue to improve ambient stability of inorganic perovskite solar cells and inspires toward further development of this material.展开更多
As a fundamental surface property of two-dimensional(2 D)materials,surface potential is critical for their emerging electronic applications and essential for van der Waals heterostructure engineering.Here,we report th...As a fundamental surface property of two-dimensional(2 D)materials,surface potential is critical for their emerging electronic applications and essential for van der Waals heterostructure engineering.Here,we report the surface potential of few-layer InSe.The effect of layer count,light intensity and different deposited substrates is considered.Few-layer InSe flakes were exfoliated from bulk InSe crystals on Si/SiO_(2)with 300-nm-thick thermal oxide and Si/SiO_(2)with 300-nm-thick thermal oxide and prefabricated micro-wells with 3μm in diameter.The samples were measured by Kelvin probe force microscopy and tuned by an integrated 405-nm(3.06 eV)laser.Based on the work function of SiO_(2)(5.00 eV),the work functions of supported and suspended InSe are determined.These results show that the work function of InSe decreases with the increase in the layer count of both supported InSe and suspended InSe.Besides,by introducing a tunable laser light,the influence of light intensity on surface potential of supported InSe was studied.The surface potential(SP)and surface potential shift between light and dark states(ASP=SP_(lignt)-SP_(dark))of supported InSe were measured and determined.These results present that the surface potential of supported InSe decreases with the increase in the light intensity and also decreases with the increase in the layer count.This is evident that light excites electrons,resulting in decreased surface potential,and the amount of electrons excited is correlated with light intensity.Meanwhile,⊿SP between light and dark states decreases with the increase in the layer count,which suggests that the influence of light illumination decreases with the increase in the layer count of few-layer InSe flakes.展开更多
The diamond-like compound Cu_(3)PSe_(4)with low lattice thermal conductivity is deemed to be a promising thermoelectric material,which can directly convert waste heat into electricity or vice versa with no moving part...The diamond-like compound Cu_(3)PSe_(4)with low lattice thermal conductivity is deemed to be a promising thermoelectric material,which can directly convert waste heat into electricity or vice versa with no moving parts and greenhouse emissions.However,its performance is limited by its low electrical conductivity.In this study,we report an effective method to enhance thermoelectric performance of Cu_(3)PSe_(4)by defect engineering.It is found that the carrier concentrations of Cu_(3-x)PSe_(4)(x=0,0.03,0.06,0.09,0.12)compounds are increased by two orders of magnitude as x>0.03,from 1×10^(17)to 1×10^(19)cm^(-3).Combined with the intrinsically low lattice thermal conductivities and enhanced electrical transport performance,a maximum zT value of 0.62 is obtained at 727 K for x=0.12 sample,revealing that Cu defect regulation can be an effective method for enhancing thermoelectric performance of Cu_(3)PSe_(4).展开更多
A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes ...A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.展开更多
The electronic structure of binary quasi-two-dimensional GeAs is investigated using first-principles calculations, and it is found that the anisotropic structure of the layered compound GeAs brings about the anisotrop...The electronic structure of binary quasi-two-dimensional GeAs is investigated using first-principles calculations, and it is found that the anisotropic structure of the layered compound GeAs brings about the anisotropy of the transport properties. Meanwhile, the band structure of GeAs exhibits a relatively large dispersion near the valence-band maximum in the Z –V direction while it is rather flat in the Z –Γ direction, which is highly desirable for good thermoelectric performance. The calculated partial charge density distribution also reveals that GeAs possesses anisotropic electrical conductivity. Based on the semi-classical Boltzmann transport theory, the anisotropic transport properties are observed, and the optimal doping concentrations are estimated. The temperature dependence transport properties of p-type GeAs are compared with the experimental data in good agreement, and the theoretical figure-of-merit ZT has been predicted as well.展开更多
The effects of biaxial strain on the electronic structure and thermoelectric properties of monolayer WSe2 have been investigated by using first-principles calculations and the semi-classical Boltzmann transport theory...The effects of biaxial strain on the electronic structure and thermoelectric properties of monolayer WSe2 have been investigated by using first-principles calculations and the semi-classical Boltzmann transport theory. The electronic band gap decreases under strain, and the band structure near the Fermi level of monolayer WSe2 is modified by the applied biaxial strain. Furthermore, the doping dependence of the thermoelectric properties of n-and p-doped monolayer WSe2 under biaxial strain is estimated. The obtained results show that the power factor of n-doped monolayer WSe2 can be increased by compressive strain while that of p-doping can be increased with tensile strain. Strain engineering thus provides a direct method to control the electronic and thermoelectric properties in these two-dimensional transition metal dichalcogenides materials.展开更多
Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is oft...Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is often influenced by electrostatic interactions.In this letter,we report a capacitive excitation PFM(ce-PFM)to minimize the electrostatic interactions.The effectiveness of ce-PFM in minimizing electrostatic interactions is demonstrated by comparing the piezoresponse and the effective piezoelectric coefficient measured by ce-PFM and conventional PFM.The effectiveness is further confirmed through the ferroelectric domain pattern imaged via ce-PFM and conventional PFM in vertical modes,with the corresponding domain contrast obtained by ce-PFM is sharper than conventional PFM.These results demonstrate ce-PFM as an effective tool to minimize the interference from electrostatic interactions and to image ferroelectric domain pattern,and it can be easily implemented in conventional atomic force microscope(AFM)setup to probe true piezoelectricity at the nanoscale.展开更多
Defect-induced charge carrier recombination at the interfaces between perovskite and adjacent charge transport layers restricts further improvements in the device performance of perovskite solar cells(PSCs).Defect pas...Defect-induced charge carrier recombination at the interfaces between perovskite and adjacent charge transport layers restricts further improvements in the device performance of perovskite solar cells(PSCs).Defect passivation at these interfaces can reduce trap states and inhibit the induced nonradiative recombination.Herein,we report a double-sided interfacial passivation via simply evaporating potassium chloride(DIP-KCl)at both the hole transport layer(HTL)/perovskite and perovskite/electron transport layer(ETL)interfaces in inverted planar PSCs.We demonstrate that the bottom KCl layer at the HTL/perovskite interface not only reduces the interfacial defects and improves the interfacial contact,but also leads to increased perovskite crystallinity,while the top KCl layer at the perovskite/ETL interface efficiently passivates the perovskite top surface defects and facilitates electron extraction at this interface.Thus,suppressed nonradiative recombination and faster charge extraction at both interfaces close to the perovskite layer can be achieved by using our DIP-KCl strategy.As a result,inverted PSCs based on DIP-KCl present an increased efficiency from 17.1% to 19.2% and enhanced stability,retaining over 90% of their initial efficiency after aging at maximum power point tracking for 1000 h.This work provides a simple and efficient way for defect passivation to further increase the efficiency and stability of PSCs.展开更多
Organic-inorganic hybrid perovskites(OIHPs)have attracted extensive research interest as a promising candidate for efficient and inexpensive solar cells.Transmission electron microscopy(TEM)characterizations that can ...Organic-inorganic hybrid perovskites(OIHPs)have attracted extensive research interest as a promising candidate for efficient and inexpensive solar cells.Transmission electron microscopy(TEM)characterizations that can benefit the fundamental understanding and the degradation mechanism are widely used for these materials.However,their sensitivity to the electron beam illumination and hence structural instabilities usually prevent us from obtaining the intrinsic information or even lead to significant artifacts.Here,we systematically investigate the structural degradation behaviors under different experimental factors to reveal the optimized conditions for TEM characterizations of OIHPs by using low-dose electron diffraction and imaging techniques.We find that a low temperature(-180°C)does not slow down the beam damage but instead induces a rapid amorphization for OIHPs.Moreover,a less severe damage is observed at a higher accelerating voltage.The beam-sensitivity is found to be facetdependent that a(100)exposed CH3NH3PbI3(MAPbI3)surface is more stable than a(001)surface.With these guidance,we successfully acquire the atomic structure of pristine MAPbI3 and identify the characterization window that is very narrow.These findings are helpful to guide future electron microscopy characterizations of these beam-sensitive materials,which are also useful for finding strategies to improve the stability and performance of the perovskite solar cells.展开更多
Magnesium(Mg)or its alloys are widely tested as potential orthopedic implants,particularly as biodegradable alloys for fracture fixation due to their mechanical properties are close to those of bone.Currently,availabl...Magnesium(Mg)or its alloys are widely tested as potential orthopedic implants,particularly as biodegradable alloys for fracture fixation due to their mechanical properties are close to those of bone.Currently,available Mg or its alloys are confronted with challenges in passing regulatory biosafety tests prior to clinical trials due to its fast degradation and associated degradation products.The degradation of Mg is accompanied by the release of Mg ions,the rise of pH and osmolality in surrounding environments.According to the standard of ISO 10993 Part 13,the pH value shall be appropriate to the site of intended use maintaining in an appropriate range.Approaches to overcome these challenges include the selection of adequate alloying elements,proper surface treatment techniques and control of the degradation rate of Mg or its alloys developed as orthopedic implants.To date,Mg or its alloy-based bone implants have not yet been widely used in clinical applications as medical implants.This review critically summarized published methods to improve the corrosion resistance of Mg and its alloys.The current progress on in vitro cytotoxicity and in vivo biocompatibility properties of these metals was also reviewed.This review aimed to provide a reference for further research and development(R&D)of biodegradable Mg and its alloys with regard to the evaluation of their corrosion process and biocompatibility and facilitation of their translation to clinical applications.展开更多
Elasticity is a fundamental mechanical property of two-dimensional(2D)materials,and is critical for their application as well as for strain engineering.However,accurate measurement of the elastic modulus of 2D materia...Elasticity is a fundamental mechanical property of two-dimensional(2D)materials,and is critical for their application as well as for strain engineering.However,accurate measurement of the elastic modulus of 2D materials remains a challenge,and the conventional suspension method suffers from a number of drawbacks.In this work,we demonstrate a method to map the in-plane Young’s modulus of mono-and bi-layer MoS_(2) on a substrate with high spatial resolution.Bimodal atomic force microscopy is used to accurately map the effective spring constant between the microscope tip and sample,and a finite element method is developed to quantitatively account for the effect of substrate stiffness on deformation.Using these methods,the in-plane Young’s modulus of monolayer MoS_(2) can be decoupled from the substrate and determined as 265±13 GPa,broadly consistent with previous reports though with substantially smaller uncertainty.It is also found that the elasticity of mono-and bi-layer MoS_(2) cannot be differentiated,which is confirmed by the first principles calculations.This method provides a convenient,robust and accurate means to map the in-plane Young’s modulus of 2D materials on a substrate.展开更多
A combination of Fresnel law and machine learning method is proposed to identify the layer counts of 2D materials.Three indexes,which are optical contrast,red-green-blue,total color difference,are presented to illustr...A combination of Fresnel law and machine learning method is proposed to identify the layer counts of 2D materials.Three indexes,which are optical contrast,red-green-blue,total color difference,are presented to illustrate and simulate the visibility of 2D materials on Si/SiO_(2) substrate,and the machine learning algorithms,which are k-mean clustering and k-nearest neighbors,are employed to obtain thickness database of 2D material and test the optical images of 2D materials via red-green-blue index.The results show that this method can provide fast,accurate and large-area property of 2D material.With the combination of artificial intelligence and nanoscience,this machine learning assisted method eases the workload and promotes fundamental research of 2D materials.展开更多
Thermoelectric materials are capable of converting heat into electricity and vice versa,and thus they are attractive in waste heat recovery and solid-state thermal management.Nevertheless,thermoelectric technologies a...Thermoelectric materials are capable of converting heat into electricity and vice versa,and thus they are attractive in waste heat recovery and solid-state thermal management.Nevertheless,thermoelectric technologies are only limited to niche applications so far,for example in space exploration,since it is rather challenging to enhance their conversion efficiency.展开更多
Human beings perceive the world through the senses of sight,hearing,smell,taste,touch,space,and balance.The first five senses are prerequisites for people to live.The sensing organs upload information to the nervous s...Human beings perceive the world through the senses of sight,hearing,smell,taste,touch,space,and balance.The first five senses are prerequisites for people to live.The sensing organs upload information to the nervous systems,including the brain,for interpreting the surrounding environment.Then,the brain sends commands to muscles reflexively to react to stimuli,including light,gas,chemicals,sound,and pressure.MXene,as an emerging two-dimensional material,has been intensively adopted in the applications of various sensors and actuators.In this review,we update the sensors to mimic five primary senses and actuators for stimulating muscles,which employ MXene-based film,membrane,and composite with other functional materials.First,a brief introduction is delivered for the structure,properties,and synthesis methods of MXenes.Then,we feed the readers the recent reports on the MXene-derived image sensors as artificial retinas,gas sensors,chemical biosensors,acoustic devices,and tactile sensors for electronic skin.Besides,the actuators of MXene-based composite are introduced.Eventually,future opportunities are given to MXene research based on the requirements of artificial intelligence and humanoid robot,which may induce prospects in accompanying healthcare and biomedical engineering applications.展开更多
Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEf...Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEformate)of 94%and a partial current density(jformate)of 34 mA·cm^(−2)at−0.8 V vs.reversible hydrogen electrode(RHE)in an H-cell.Moreover,the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm^(−2)with formate selectivity up to 92%in a flow cell and could steadily operate for at least 20 h.Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)confirmed that the PdBi interface could greatly weaken the adsorption of*CO intermediates due to electronic and geometric effects.Density functional theory(DFT)calculations also established that the PdBi interface regulated the CO_(2)-to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of*CO intermediates on the catalyst surface.This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations.展开更多
Ternary Ⅰ–Ⅲ–Ⅵquantum dots（QDs） of chalcopyrite semiconductors exhibit excellent optical properties in solar cells. In this study, ternary chalcopyrite CuGaS2nanocrystals（2–5 nm） were one-pot anchored on TiO2...Ternary Ⅰ–Ⅲ–Ⅵquantum dots（QDs） of chalcopyrite semiconductors exhibit excellent optical properties in solar cells. In this study, ternary chalcopyrite CuGaS2nanocrystals（2–5 nm） were one-pot anchored on TiO2nanoparticles（TiO2@CGS） without any long ligand. The solar cell with TiO2@CuGaS2/N719 has a power conversion efficiency of7.4%, which is 23% higher than that of monosensitized dye solar cell. Anchoring CuGaS2 QDs on semiconductor nanoparticles to form QDs/dye co-sensitized solar cells is a promising and feasible approach to enhance light absorption,charge carrier generation as well as to facilitate electron injection comparing to conventional mono-dye sensitized solar cells.展开更多
Since its first report in 2009,CH_3NH_3PbI_3-based perovskite solar cells(PSCs)have emerged as one of the most exciting developments in the next generation photovoltaic(PV)technologies[1],with its PV conversion effici...Since its first report in 2009,CH_3NH_3PbI_3-based perovskite solar cells(PSCs)have emerged as one of the most exciting developments in the next generation photovoltaic(PV)technologies[1],with its PV conversion efficiency(PCE)rising spectacularly from3.81% to 22.1% in just 7 years.Such rapid advance is展开更多
Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related...Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related to the vacancies and impurities in the electrode.To investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal method.And the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other means.As the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling stability.Compared with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great improvement.The asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling stability.The feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.展开更多
Effective electron selective layer （ESL） is critical for the power conversion efficiency in organometal halide- based perovskite solar cells （PSCs）. In this work, a spincoating process has been developed to fabric...Effective electron selective layer （ESL） is critical for the power conversion efficiency in organometal halide- based perovskite solar cells （PSCs）. In this work, a spincoating process has been developed to fabricate high quality nanocrystalline SnO2 film at 100℃ without further sintering at higher temperature. When used as ESL in PSCs, such SnO2 film shows greater electron extraction ability and higher efficiency than TiO2 film processed under similar condition, as evidenced by the efficient time-resolved photoluminescence （TRPL） quenching SnO2/CH3NH3PbI3 film. As a resuit, the SnO2-based PSCs possess higher open circuit voltage of 0.91 V, short circuit current density of 20.73 mA cm^-2, and fill factor of 64.25%, corresponding to a conversion efficiency of 12.10%, compared with 7.16% of TiO2-based PSCs. This demonstrates the great potential of applying spin-coating sintering-free process for the low-cost and large-scale manufacturing of PSCs.展开更多
During recent years,flexible electronics that are highlybendable,foldable,stretchable and twistable without sacrificing their functional performances have attracted a great number of researchers and engineers[1e5],and...During recent years,flexible electronics that are highlybendable,foldable,stretchable and twistable without sacrificing their functional performances have attracted a great number of researchers and engineers[1e5],and the rapid development of flexible electronics has promised to revolutionize the consumer electronics[6].For example,wearable devices[7],foldable displays[8],implanted systems[3]and brain-machine interfaces[9]have been emerged as innovative technologies.What is more,flexoelectricity and anomalous polarization behavior have been observed and manipulated[10,11],thanks to the flexibility rendered at the materials,structures,and devices level.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51672094,51861145404 and 51822203)the China Postdoctoral Science Foundation(No.2016M602286)+2 种基金the Self-determined and Innovative Research Funds of HUST(No.2016JCTD111)Shenzhen Science and Technology Innovation Committee(No.JCYJ20170307165905513)the Natural Science Foundation of Guangdong Province(No.2017A030313342).
文摘Inorganic cesium metal halide perovskites have gained research interest as absorbers in perovskite solar cells due to their superior thermal stability.Among these,CsPbI2Br,with a narrower band gap than CsPbBr3 and a better phase stability than CsPbI3,has received tremendous interest of the researchers.However,CsPbI2 Br takes adverse phase transfer easily with an exposure to the water vapor in ambient air which not only brings inconvenience for researches but also puts forward very high requirement for encapsulation.Herein,a dense and uniform film is obtained by incorporating hydrophobic CH3NH3Cl(MACl)into the precursor solution.Being attributed to a good passivation effect,the defect density is decreased from3.12×1016 to 1.49×1016 cm-3 and the average photoluminescence lifetime is increased from 8.84 to 20.6 ns.The photovoltaic device achieves a high open-circuit voltage of 1.22 V based on optimized MACl-doped film and accordingly a higher power conversion efficiency(PCE) of 12.9% which is 21.7% higher than the pristine CsPbI2Br device with PCE of 10.6%.In addition,the ambient stability of MACl-doped device has been enhanced,which is greatly attributed to the hydrophobic properties of MACl.This work provides a clue to improve ambient stability of inorganic perovskite solar cells and inspires toward further development of this material.
基金the Key-Area Research and Development Program of Guangdong Province(No.2018B010109009)the Shenzhen Science and Technology Innovation Committee(Nos.JCYJ20170818155752559 and JCYJ20170818160815002)+3 种基金the Instrument Developing Project of Chinese Academy of Sciences(No.ZDKYYQ20180004)the National Natural Science Foundation of China(No.11872203)the National Natural Science Foundation of China for Creative Research Groups(No.51921003)support of the China Scholarship Council。
文摘As a fundamental surface property of two-dimensional(2 D)materials,surface potential is critical for their emerging electronic applications and essential for van der Waals heterostructure engineering.Here,we report the surface potential of few-layer InSe.The effect of layer count,light intensity and different deposited substrates is considered.Few-layer InSe flakes were exfoliated from bulk InSe crystals on Si/SiO_(2)with 300-nm-thick thermal oxide and Si/SiO_(2)with 300-nm-thick thermal oxide and prefabricated micro-wells with 3μm in diameter.The samples were measured by Kelvin probe force microscopy and tuned by an integrated 405-nm(3.06 eV)laser.Based on the work function of SiO_(2)(5.00 eV),the work functions of supported and suspended InSe are determined.These results show that the work function of InSe decreases with the increase in the layer count of both supported InSe and suspended InSe.Besides,by introducing a tunable laser light,the influence of light intensity on surface potential of supported InSe was studied.The surface potential(SP)and surface potential shift between light and dark states(ASP=SP_(lignt)-SP_(dark))of supported InSe were measured and determined.These results present that the surface potential of supported InSe decreases with the increase in the light intensity and also decreases with the increase in the layer count.This is evident that light excites electrons,resulting in decreased surface potential,and the amount of electrons excited is correlated with light intensity.Meanwhile,⊿SP between light and dark states decreases with the increase in the layer count,which suggests that the influence of light illumination decreases with the increase in the layer count of few-layer InSe flakes.
基金the Graduate Scientific Research and Innovation Foundation of Chongqing,China(No.CYB 19064)the Project for Fundamental and Frontier Research in Chongqing(No.CSTC2017JCYJAX0388)+2 种基金Shenzhen Science and Technology Innovation Committee(No.JCYJ20170818155752559)the National Natural Science Foundation of China(Nos.51772035,11674040 and 51472036)the Fundamental Research Funds for the Central Universities(No.106112017CDJQJ308821)。
文摘The diamond-like compound Cu_(3)PSe_(4)with low lattice thermal conductivity is deemed to be a promising thermoelectric material,which can directly convert waste heat into electricity or vice versa with no moving parts and greenhouse emissions.However,its performance is limited by its low electrical conductivity.In this study,we report an effective method to enhance thermoelectric performance of Cu_(3)PSe_(4)by defect engineering.It is found that the carrier concentrations of Cu_(3-x)PSe_(4)(x=0,0.03,0.06,0.09,0.12)compounds are increased by two orders of magnitude as x>0.03,from 1×10^(17)to 1×10^(19)cm^(-3).Combined with the intrinsically low lattice thermal conductivities and enhanced electrical transport performance,a maximum zT value of 0.62 is obtained at 727 K for x=0.12 sample,revealing that Cu defect regulation can be an effective method for enhancing thermoelectric performance of Cu_(3)PSe_(4).
基金National Natural Science Foundation of China,Grant/Award Numbers:21905265,52072322,U1930402,61974042National Science Foundation,Civil,Mechanical and Manufacturing Innovation,Grant/Award Number:1911905+3 种基金Fundamental Research Funds for the Central Universities,Grant/Award Number:WK2060140026Department of Science and Technology of Sichuan Province,Grant/Award Numbers:2019‐GH02‐00052‐HZ,2019YFG0220Scientific and Technological Innovation Foundation of Shunde Graduate School,Grant/Award Number:BK19BE024National Key Research and Development Program of China,Grant/Award Number:2017YFA0303403。
文摘A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFA0201001the National Natural Science Foundation of China under Grant No 11627801the Education Bureau of Hunan Province of China under Grant No 16C0626
文摘The electronic structure of binary quasi-two-dimensional GeAs is investigated using first-principles calculations, and it is found that the anisotropic structure of the layered compound GeAs brings about the anisotropy of the transport properties. Meanwhile, the band structure of GeAs exhibits a relatively large dispersion near the valence-band maximum in the Z –V direction while it is rather flat in the Z –Γ direction, which is highly desirable for good thermoelectric performance. The calculated partial charge density distribution also reveals that GeAs possesses anisotropic electrical conductivity. Based on the semi-classical Boltzmann transport theory, the anisotropic transport properties are observed, and the optimal doping concentrations are estimated. The temperature dependence transport properties of p-type GeAs are compared with the experimental data in good agreement, and the theoretical figure-of-merit ZT has been predicted as well.
基金Project supported by the National Natural Science Foundation of China(Grant No.11627801)the Research Foundation of Education Bureau of Hunan Province of China(Grant Nos.15B083 and 17B090)
文摘The effects of biaxial strain on the electronic structure and thermoelectric properties of monolayer WSe2 have been investigated by using first-principles calculations and the semi-classical Boltzmann transport theory. The electronic band gap decreases under strain, and the band structure near the Fermi level of monolayer WSe2 is modified by the applied biaxial strain. Furthermore, the doping dependence of the thermoelectric properties of n-and p-doped monolayer WSe2 under biaxial strain is estimated. The obtained results show that the power factor of n-doped monolayer WSe2 can be increased by compressive strain while that of p-doping can be increased with tensile strain. Strain engineering thus provides a direct method to control the electronic and thermoelectric properties in these two-dimensional transition metal dichalcogenides materials.
基金We acknowledge the National Key Research and Development Program of China(Grant 2016YFA0201001)the National Natural Science Foundation of China(Grants 11372268,11627801,and 1472236)+2 种基金Unite State National Science Foundation(Grant CBET-1435968)the Leading Talents Program of Guangdong Province(Grant 2016LJ06C372)Shenzhen Science and Technology Innovation Committee(Grant KQJSCX20170331162214306).
文摘Piezoresponse force microscopy(PFM)has emerged as one of the most powerful techniques to probe ferroelectric materials at the nanoscale,yet it has been increasingly recognized that piezoresponse measured by PFM is often influenced by electrostatic interactions.In this letter,we report a capacitive excitation PFM(ce-PFM)to minimize the electrostatic interactions.The effectiveness of ce-PFM in minimizing electrostatic interactions is demonstrated by comparing the piezoresponse and the effective piezoelectric coefficient measured by ce-PFM and conventional PFM.The effectiveness is further confirmed through the ferroelectric domain pattern imaged via ce-PFM and conventional PFM in vertical modes,with the corresponding domain contrast obtained by ce-PFM is sharper than conventional PFM.These results demonstrate ce-PFM as an effective tool to minimize the interference from electrostatic interactions and to image ferroelectric domain pattern,and it can be easily implemented in conventional atomic force microscope(AFM)setup to probe true piezoelectricity at the nanoscale.
基金financially supported by the National Natural Science Foundation of China,China(51672094,51861145404,51822203,and 11627801)the National Key Research and Development Program of China,China(2016YFA0201001)+4 种基金the China Postdoctoral Science Foundation(2016M602286)the Fundamental Research Funds for the Central Universities,China(2016JCTD111,2018RCPY003,2020kfy XJJS008)the Shenzhen Science and Technology Innovation Committee,China(JCYJ20170307165905513,JCYJ20180507182257563)the Natural Science Foundation of Guangdong Province,China(2017A030313342)the Outstanding Young Talent Research Fund of Zhengzhou University,China。
文摘Defect-induced charge carrier recombination at the interfaces between perovskite and adjacent charge transport layers restricts further improvements in the device performance of perovskite solar cells(PSCs).Defect passivation at these interfaces can reduce trap states and inhibit the induced nonradiative recombination.Herein,we report a double-sided interfacial passivation via simply evaporating potassium chloride(DIP-KCl)at both the hole transport layer(HTL)/perovskite and perovskite/electron transport layer(ETL)interfaces in inverted planar PSCs.We demonstrate that the bottom KCl layer at the HTL/perovskite interface not only reduces the interfacial defects and improves the interfacial contact,but also leads to increased perovskite crystallinity,while the top KCl layer at the perovskite/ETL interface efficiently passivates the perovskite top surface defects and facilitates electron extraction at this interface.Thus,suppressed nonradiative recombination and faster charge extraction at both interfaces close to the perovskite layer can be achieved by using our DIP-KCl strategy.As a result,inverted PSCs based on DIP-KCl present an increased efficiency from 17.1% to 19.2% and enhanced stability,retaining over 90% of their initial efficiency after aging at maximum power point tracking for 1000 h.This work provides a simple and efficient way for defect passivation to further increase the efficiency and stability of PSCs.
基金supported by the Key Area Research and Development Program of Guangdong Province(2018B010109009)the National Key R&D Program of China(2016YFA0300804,2016YFA0300903,and 2016YFA0201001)+6 种基金the National Natural Science Foundation of China(51672007,11974023,51575135,U1537206,and 11772207)National Equipment Program of China(ZDYZ2015-1)“2011 Program”Peking-Tsinghua-IOP Collaborative Innovation Center of Quantum MatterNatural Science Foundation of Hebei Province for Distinguished Young Scholar(A2019210204)High Level Talent Support Project in Hebei(C201821)State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics(MCMS-E0519G04)Youth Top-notch Talents Supporting Plan of Hebei Province。
文摘Organic-inorganic hybrid perovskites(OIHPs)have attracted extensive research interest as a promising candidate for efficient and inexpensive solar cells.Transmission electron microscopy(TEM)characterizations that can benefit the fundamental understanding and the degradation mechanism are widely used for these materials.However,their sensitivity to the electron beam illumination and hence structural instabilities usually prevent us from obtaining the intrinsic information or even lead to significant artifacts.Here,we systematically investigate the structural degradation behaviors under different experimental factors to reveal the optimized conditions for TEM characterizations of OIHPs by using low-dose electron diffraction and imaging techniques.We find that a low temperature(-180°C)does not slow down the beam damage but instead induces a rapid amorphization for OIHPs.Moreover,a less severe damage is observed at a higher accelerating voltage.The beam-sensitivity is found to be facetdependent that a(100)exposed CH3NH3PbI3(MAPbI3)surface is more stable than a(001)surface.With these guidance,we successfully acquire the atomic structure of pristine MAPbI3 and identify the characterization window that is very narrow.These findings are helpful to guide future electron microscopy characterizations of these beam-sensitive materials,which are also useful for finding strategies to improve the stability and performance of the perovskite solar cells.
基金This work was supported by the National High Technology Research and Development Program of China(Youth 863 Program,Project No.2015AA020935)National Natural Science Foundation of China grant(Project No.51573206)+1 种基金Shenzhen Fundamental Research Foundation(Project No.JCYJ20150731154850925,JCYJ20150521144321001,JSGG20151030140325149,CXZZ20150529144128031)Hong Kong GRF(CUHK No.14140816).
文摘Magnesium(Mg)or its alloys are widely tested as potential orthopedic implants,particularly as biodegradable alloys for fracture fixation due to their mechanical properties are close to those of bone.Currently,available Mg or its alloys are confronted with challenges in passing regulatory biosafety tests prior to clinical trials due to its fast degradation and associated degradation products.The degradation of Mg is accompanied by the release of Mg ions,the rise of pH and osmolality in surrounding environments.According to the standard of ISO 10993 Part 13,the pH value shall be appropriate to the site of intended use maintaining in an appropriate range.Approaches to overcome these challenges include the selection of adequate alloying elements,proper surface treatment techniques and control of the degradation rate of Mg or its alloys developed as orthopedic implants.To date,Mg or its alloy-based bone implants have not yet been widely used in clinical applications as medical implants.This review critically summarized published methods to improve the corrosion resistance of Mg and its alloys.The current progress on in vitro cytotoxicity and in vivo biocompatibility properties of these metals was also reviewed.This review aimed to provide a reference for further research and development(R&D)of biodegradable Mg and its alloys with regard to the evaluation of their corrosion process and biocompatibility and facilitation of their translation to clinical applications.
基金We acknowledge National Key Research and Development Program of China(2016YFA0201001)National Natural Science Foundation of China(11627801,11232007,11472130,11472236,and 51702351)+3 种基金Shenzhen Science and Technology Innovation Committee(KQJSCX20170331162214306,JCYJ20170413152832151,JCYJ20170818160815002)US National Science Foundation(CBET-1435968)the Leading Talents Program of Guangdong Province(2016LJ06C372)Shenzhen Programs for Science and Technology Development(JSGG20160229204218661).
文摘Elasticity is a fundamental mechanical property of two-dimensional(2D)materials,and is critical for their application as well as for strain engineering.However,accurate measurement of the elastic modulus of 2D materials remains a challenge,and the conventional suspension method suffers from a number of drawbacks.In this work,we demonstrate a method to map the in-plane Young’s modulus of mono-and bi-layer MoS_(2) on a substrate with high spatial resolution.Bimodal atomic force microscopy is used to accurately map the effective spring constant between the microscope tip and sample,and a finite element method is developed to quantitatively account for the effect of substrate stiffness on deformation.Using these methods,the in-plane Young’s modulus of monolayer MoS_(2) can be decoupled from the substrate and determined as 265±13 GPa,broadly consistent with previous reports though with substantially smaller uncertainty.It is also found that the elasticity of mono-and bi-layer MoS_(2) cannot be differentiated,which is confirmed by the first principles calculations.This method provides a convenient,robust and accurate means to map the in-plane Young’s modulus of 2D materials on a substrate.
基金National Key Research and Development Program of China(2016YFA0201001)National Natural Science Foundation of China(11627801,11472130,11872203,and 11572276)+3 种基金Shenzhen Science and Technology Innovation Committee(JCYJ20170818160815002)Shenzhen Science and Technology Research Funding(JCYJ20160608141439330)Natural Science Foundation of Xinjiang(2017D01C055)Wuhan University of Technology(2018-KF-14).
文摘A combination of Fresnel law and machine learning method is proposed to identify the layer counts of 2D materials.Three indexes,which are optical contrast,red-green-blue,total color difference,are presented to illustrate and simulate the visibility of 2D materials on Si/SiO_(2) substrate,and the machine learning algorithms,which are k-mean clustering and k-nearest neighbors,are employed to obtain thickness database of 2D material and test the optical images of 2D materials via red-green-blue index.The results show that this method can provide fast,accurate and large-area property of 2D material.With the combination of artificial intelligence and nanoscience,this machine learning assisted method eases the workload and promotes fundamental research of 2D materials.
文摘Thermoelectric materials are capable of converting heat into electricity and vice versa,and thus they are attractive in waste heat recovery and solid-state thermal management.Nevertheless,thermoelectric technologies are only limited to niche applications so far,for example in space exploration,since it is rather challenging to enhance their conversion efficiency.
基金the National Natural Science Foundation of China(No.51802116)the Natural Science Foundation of Shandong Province for the Natural Science Fund for Excellent Young Scholars of Shandong Province(No.ZR202112010179)+9 种基金the Doctoral Fund(No.ZR2019BEM040)H.L.acknowledges the“20 Items of University”Project of Jinan(No.2018GXRC031)W.Z.thanks the Major Scientific and Technological Innovation Project of Shandong Province(No.2021CXGC010603)the National Natural Science Foundation of China(No.52022037)Taishan Scholars Project Special Funds(No.TSQN201812083)supported by the Foundation(No.GZKF202107)of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology,Shandong Academy of Sciencesthe National Natural Science Foundation of China(No.22003074)the National Natural Science Foundation of China(No.52071225)the National Science Center and the Czech Republic under the European Regional Development Fund(ERDF)program“Institute of Environmental Technology-Excellent Research”(No.CZ.02.1.01/0.0/0.0/16_019/0000853)the Sino-German Research Institute for support(No.GZ 1400).
文摘Human beings perceive the world through the senses of sight,hearing,smell,taste,touch,space,and balance.The first five senses are prerequisites for people to live.The sensing organs upload information to the nervous systems,including the brain,for interpreting the surrounding environment.Then,the brain sends commands to muscles reflexively to react to stimuli,including light,gas,chemicals,sound,and pressure.MXene,as an emerging two-dimensional material,has been intensively adopted in the applications of various sensors and actuators.In this review,we update the sensors to mimic five primary senses and actuators for stimulating muscles,which employ MXene-based film,membrane,and composite with other functional materials.First,a brief introduction is delivered for the structure,properties,and synthesis methods of MXenes.Then,we feed the readers the recent reports on the MXene-derived image sensors as artificial retinas,gas sensors,chemical biosensors,acoustic devices,and tactile sensors for electronic skin.Besides,the actuators of MXene-based composite are introduced.Eventually,future opportunities are given to MXene research based on the requirements of artificial intelligence and humanoid robot,which may induce prospects in accompanying healthcare and biomedical engineering applications.
基金supported by the National Natural Science Foundation of China(Nos.22003074 and 22002087)Youth Innovation Promotion Association CAS,Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials(No.2021MCIMKF03)Baoshan Iron&Steel Co.,Ltd.(Baosteel),located in Shanghai,China.
文摘Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEformate)of 94%and a partial current density(jformate)of 34 mA·cm^(−2)at−0.8 V vs.reversible hydrogen electrode(RHE)in an H-cell.Moreover,the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm^(−2)with formate selectivity up to 92%in a flow cell and could steadily operate for at least 20 h.Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)confirmed that the PdBi interface could greatly weaken the adsorption of*CO intermediates due to electronic and geometric effects.Density functional theory(DFT)calculations also established that the PdBi interface regulated the CO_(2)-to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of*CO intermediates on the catalyst surface.This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations.
基金the financial support from the National Key Research and Development Program of China(2016YFA0201001)the National Natural Science Foundation of China(11627801,51102172 and 11772207)+7 种基金Science and Technology Plan of Shenzhen City(JCYJ20160331191436180)the Leading Talents of Guangdong Province Program(2016LJ06C372)the Natural ScienceFoundation for Outstanding Young Researcher in Hebei Province(E2016210093)the Key Program of Educational Commission of Hebei Province of China(ZD2016022)the Youth Top-notch Talents Supporting Plan of Hebei Provincethe Graduate Innovation Foundation of Shijiazhuang Tiedao UniversityHebei Provincial Key Laboratory of Traffic Engineering materialsHebei Key Discipline Construction Project
文摘Ternary Ⅰ–Ⅲ–Ⅵquantum dots（QDs） of chalcopyrite semiconductors exhibit excellent optical properties in solar cells. In this study, ternary chalcopyrite CuGaS2nanocrystals（2–5 nm） were one-pot anchored on TiO2nanoparticles（TiO2@CGS） without any long ligand. The solar cell with TiO2@CuGaS2/N719 has a power conversion efficiency of7.4%, which is 23% higher than that of monosensitized dye solar cell. Anchoring CuGaS2 QDs on semiconductor nanoparticles to form QDs/dye co-sensitized solar cells is a promising and feasible approach to enhance light absorption,charge carrier generation as well as to facilitate electron injection comparing to conventional mono-dye sensitized solar cells.
基金supported by the National Key Research and Development Program of China(2016YFA0201001,2016YFA0300804)the National Natural Science Foundation of China(11627801,51102172,51672007,51502007,11772207)+4 种基金the Leading Talents Program of Guangdong Province(2016LJ06C372)Shenzhen Science and Technology Innovation Committee(JCYJ20170307165905513,JCYJ20170413152832151)the Natural Science Foundation for Outstanding Young Researcher in Hebei Province(E2016210093)the Key Program of Educational Commission of Hebei Province of China(ZD2016022)the Youth Top-notch Talents Supporting Plan of Hebei Province
文摘Since its first report in 2009,CH_3NH_3PbI_3-based perovskite solar cells(PSCs)have emerged as one of the most exciting developments in the next generation photovoltaic(PV)technologies[1],with its PV conversion efficiency(PCE)rising spectacularly from3.81% to 22.1% in just 7 years.Such rapid advance is
基金supported by the National Natural Science Foundation of China(61376011 and 51402141)Gansu Provincial Natural Science Foundation(17JR5RA198)+1 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2018-119 and lzujbky-2018-ct08)Shenzhen Science and Technology Innovation Committee(JCYJ20170818155813437)。
文摘Nowadays,it is a matter of great concern to design electrode materials with excellent electrochemical performance for supercapacitors by a safe,efficient and simple method.And these characteristics are usually related to the vacancies and impurities in the electrode.To investigate the effect of the vacancies on the electrochemical properties of the supercapacitor cathode material,the uniform reduced CoNi2S4(r-CoNi2S4)nanosheets with sulfur vacancies have been successfully prepared by a one-step hydrothermal method.And the formation of sulfur vacancies are characterized by Raman,X-ray photoelectron spectroscopy and other means.As the electrode for supercapacitor,the r-CoNi2S4 nanosheet electrode delivers a high capacity of 1918.9 Fg-1 at a current density of 1 A g-1,superior rate capability(87.9%retention at a current density of 20 A g-1)and extraordinary cycling stability.Compared with the original CoNi2S4 nanosheet electrode(1226 F g-1at current density of 1 A g-1),the r-CoNi2S4 nanosheet electrode shows a great improvement.The asymmetric supercapacitor based on the r-CoNi2S4 positive electrode and activated carbon negative electrode exhibits a high energy density of 30.3 Wh kg-1 at a power density of 802.1 W kg-1,as well as excellent long-term cycling stability.The feasibility and great potential of the device in practical applications have been successfully proved by lightening the light emitting diodes of three different colors.
基金supported by the National Key Research and Development Program of China(2016YFA0201001)National Natural Science Foundation of China(11627801,51102172)+3 种基金Science and Technology Plan of Shenzhen City(JCYJ20160331191436180)Natural Science Foundation for Outstanding Young Researcher in Hebei Province(E2016210093)the Key Program of Educational Commission of Hebei Province of China(ZD2016022)the Youth Top-notch Talents Supporting Plan of Hebei Province,Hebei Provincial Key Laboratory of Traffic Engineering materials and Hebei Key Discipline Construction Project
文摘Effective electron selective layer （ESL） is critical for the power conversion efficiency in organometal halide- based perovskite solar cells （PSCs）. In this work, a spincoating process has been developed to fabricate high quality nanocrystalline SnO2 film at 100℃ without further sintering at higher temperature. When used as ESL in PSCs, such SnO2 film shows greater electron extraction ability and higher efficiency than TiO2 film processed under similar condition, as evidenced by the efficient time-resolved photoluminescence （TRPL） quenching SnO2/CH3NH3PbI3 film. As a resuit, the SnO2-based PSCs possess higher open circuit voltage of 0.91 V, short circuit current density of 20.73 mA cm^-2, and fill factor of 64.25%, corresponding to a conversion efficiency of 12.10%, compared with 7.16% of TiO2-based PSCs. This demonstrates the great potential of applying spin-coating sintering-free process for the low-cost and large-scale manufacturing of PSCs.
基金the support of National Natural Science Foundation of China(51902337)Shenzhen Science and Technology Innovation Committee(KQTD20170810160424889)+1 种基金China Postdoctoral Science Foundation(2018M643249)SIAT Innovation Program for Excellent Young Researchers(201817).
文摘During recent years,flexible electronics that are highlybendable,foldable,stretchable and twistable without sacrificing their functional performances have attracted a great number of researchers and engineers[1e5],and the rapid development of flexible electronics has promised to revolutionize the consumer electronics[6].For example,wearable devices[7],foldable displays[8],implanted systems[3]and brain-machine interfaces[9]have been emerged as innovative technologies.What is more,flexoelectricity and anomalous polarization behavior have been observed and manipulated[10,11],thanks to the flexibility rendered at the materials,structures,and devices level.
