Two-dimension(2D)van der Waals heterojunction holds essential promise in achieving high-performance flexible near-infrared(NIR)photodetector.Here,we report the successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene base...Two-dimension(2D)van der Waals heterojunction holds essential promise in achieving high-performance flexible near-infrared(NIR)photodetector.Here,we report the successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene based flexible NIR photodetector array via a facile photolithography technology.The single ZnSb/Ti_(3)C_(2)T_(x)photodetector exhibited a high light-to-dark current ratio of 4.98,fast response/recovery time(2.5/1.3 s)and excellent stability due to the tight connection between 2D ZnSb nanoplates and 2D Ti_(3)C_(2)T_(x)MXene nanoflakes,and the formed 2D van der Waals heterojunction.Thin polyethylene terephthalate(PET)substrate enables the ZnSb/Ti_(3)C_(2)T_(x)photodetector withstand bending such that stable photoelectrical properties with non-obvious change were maintained over 5000 bending cycles.Moreover,the ZnSb/Ti_(3)C_(2)T_(x)photodetectors were integrated into a 26×5 device array,realizing a NIR image sensing application.展开更多
We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave (MW), long-wave (LW), and very long-wave (VLW) detections. The detector structure consists of three contacts of NIPIN archite...We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave (MW), long-wave (LW), and very long-wave (VLW) detections. The detector structure consists of three contacts of NIPIN architecture for MW and LW detections, and hetero-junction NIP architecture for VLW detection. It is found that the spectral crosstalks can be significantly reduced by controlling the minority carriers transport via doping beryllium in the two active regions of NIPIN section. The crosstalk detection at MW, LW, and VLW signals are achieved by selecting the bias voltages on the device. At 77K, the cutoff wavelengths of the three-color detection are 5.3μm (at OmV), 141μm (at 300mV) and 19μm (at -20mV) with the detectivities of 4.6xlO11 cm.Hzl/ZW-1, 2.3×10^10 cm.Hzl/2W-1, and 1.0×10^10cm.Hzl/2W-1 for MW, LW and VLW. The crosstalks of the MW channel, LW channel, and VLW channel are almost 0, 0.25, and 0.6, respectively.展开更多
Sweat loss monitoring is important for understanding the body’s thermoregulation and hydration status,as well as for comprehensive sweat analysis.Despite recent advances,developing a low-cost,scalable,and universal m...Sweat loss monitoring is important for understanding the body’s thermoregulation and hydration status,as well as for comprehensive sweat analysis.Despite recent advances,developing a low-cost,scalable,and universal method for the fabrication of colorimetric microfluidics designed for sweat loss monitoring remains challenging.In this study,we propose a novel laserengraved surface roughening strategy for various flexible substrates.This process permits the construction of microchannels that show distinct structural reflectance changes before and after sweat filling.By leveraging these unique optical properties,we have developed a fully laser-engraved microfluidic device for the quantification of naked-eye sweat loss.This sweat loss sensor is capable of a volume resolution of 0.5µL and a total volume capacity of 11µL,and can be customized to meet different performance requirements.Moreover,we report the development of a crosstalk-free dual-mode sweat microfluidic system that integrates an Ag/AgCl chloride sensor and a matching wireless measurement flexible printed circuit board.This integrated system enables the real-time monitoring of colorimetric sweat loss signals and potential ion concentration signals without crosstalk.Finally,we demonstrate the potential practical use of this microfluidic sweat loss sensor and its integrated system for sports medicine via on-body studies.展开更多
High performance short-wavelength infrared PBn photodetectors based on InAs/GaSb/AlSb superlattices on GaSb substrate have been demonstrated.At 300 K,the device exhibits a 50%cut-off wavelength of~2.1μm as predicted ...High performance short-wavelength infrared PBn photodetectors based on InAs/GaSb/AlSb superlattices on GaSb substrate have been demonstrated.At 300 K,the device exhibits a 50%cut-off wavelength of~2.1μm as predicted from the band structure calculation;the device responsivity peaks at 0.85 A/W,corresponding to a quantum efficiency(QE)of 56%for 2.0μm-thick absorption region.The dark current density of 1.03×10^(-3)A/cm^(2)is obtained under 50 mV applied bias.The device exhibits a saturated dark current shot noise limited specific detectivity(D*)of 3.29×1010cm·Hz^(1/2)/W(at a peak responsivity of 2.0μm)under-50 mV applied bias.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion ...Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.展开更多
InGaSb/AlGaAsSb double-quantum-well diode lasers emitting around 2 μm are demonstrated. The AlGaAsSb barriers of the lasers are grown with digital alloy techniques consisting of binary AlSb/AlAs/GaSb short-period pai...InGaSb/AlGaAsSb double-quantum-well diode lasers emitting around 2 μm are demonstrated. The AlGaAsSb barriers of the lasers are grown with digital alloy techniques consisting of binary AlSb/AlAs/GaSb short-period pairs. Peak power conversion efficiency of 26% and an efficiency higher than 16% at 1 W are achieved at continuous-wave operation for a 2-mm-long and 100-μm-wide stripe laser. The maximum output power of a single emitter reaches to 1.4 W at 7 A.19-emitter bars with maximum efficiency higher than 20% and maximum power of 16 W are fabricated. Lasers with the short-period-pair barriers are proved to have improved temperature properties and wavelength stabilities. The characteristic temperature(T_0) is up to 140?C near room temperature(25–55?C).展开更多
InAs/GaSb superlattiee (SL) midwave infrared photovoltaic detectors are grown by molecular beam epitaxy on GaSb(001) residud p-type substrates. A thick GaSb layer is grown under the optimized growth condition as a...InAs/GaSb superlattiee (SL) midwave infrared photovoltaic detectors are grown by molecular beam epitaxy on GaSb(001) residud p-type substrates. A thick GaSb layer is grown under the optimized growth condition as a buffer layer. The detectors containing a 320-period 8ML/SML InAs/GaS5 SL active layer are fabricated with a series pixel area using anode sulfide passivation. Corresponding to 50% cutoff wavelengths of 5.0 μm at 77K, the peak directivity of the detectors is 1.6 × 10^10 cm.Hz^1/2 W^-1 at 77K.展开更多
To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on ele...To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.展开更多
Uniaxial stress is a powerful tool for tuning exciton emitting wavelength, polarization, fine-structure splitting (FSS), and the symmetry of quantum dots (QDs). Here, we present a technique for applying uniaxial stres...Uniaxial stress is a powerful tool for tuning exciton emitting wavelength, polarization, fine-structure splitting (FSS), and the symmetry of quantum dots (QDs). Here, we present a technique for applying uniaxial stress, which enables us in situ to tune exciton optical properties at low temperature down to 15 K with high tuning precision. The design and operation of the device are described in detail. This technique provides a simple and convenient approach to tune QD structural symmetry, exciton energy and biexciton binding energy. It can be utilized for generating entangled and indistinguishable photons. Moreover, this device can be employed for tuning optical properties of thin film materials at low temperature.展开更多
In this report, the effect of temperature on the In As/Al Sb heterojunction and high-electron-mobility transistors(HEMTs) with a gate length of 2 μm are discussed comprehensively. The results indicate that device p...In this report, the effect of temperature on the In As/Al Sb heterojunction and high-electron-mobility transistors(HEMTs) with a gate length of 2 μm are discussed comprehensively. The results indicate that device performance is greatly improved at cryogenic temperatures. It is also observed that the device performance at 90 K is significantly improved with 27% lower gate leakage current, 12% higher maximum drain current, and 22.5% higher peak transconductance compared to 300 K. The temperature dependence of mobility and the two-dimensional electron gas concentration in the In As/Al Sb heterojunction for the temperature range 90 K-300 K is also investigated. The electron mobility at 90 K(42560 cm2/V·s)is 2.5 times higher than its value at 300 K(16911 cm^2/V·s) because of the weaker lattice vibration and the impurity ionization at cryogenic temperatures, which corresponds to a reduced scattering rate and higher mobility. We also noted that the two-dimensional electron gas concentration decreases slightly from 1.99 × 10^(12) cm^(-2) at 300 K to 1.7 × 10^(12) cm^(-2) at 90 K with a decrease in temperature due to the lower ionization at cryogenic temperature and the nearly constant ?Ec.展开更多
We develop a modified two-step method of growing high-density and narrow size-distribution InAs/GaAs quantum dots (QDs) by molecular beam epitaxy. In the first step, high-density small InAs QDs are formed by optimiz...We develop a modified two-step method of growing high-density and narrow size-distribution InAs/GaAs quantum dots (QDs) by molecular beam epitaxy. In the first step, high-density small InAs QDs are formed by optimizing the continuous deposition amount. In the second step, deposition is carried out with a long growth interruption for every 0.1 InAs monolayer. Atomic force microscope images show that the high-density (~5.9 × 10^11 cm^-2) good size-uniformity InAs QDs are achieved. The strong intensity and narrow linewidth (27.7 meV) of the photoluminescence spectrum show that the QDs grown in this two-step method have a good optical quality.展开更多
Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP micro...Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP microwires(RPP-MWs)and compared it with a 2D-RPP photodetector.The results show that the RPP-MWs photodetector possesses a wider photoresponse range and higher responsivities of 233 A/W in the visible band and 30 A/W in the near-infrared(NIR)band.The analyses show that the synthesized RPP-MWs have a multi-layer,heterogeneous core-shell structure.This structure gives RPP-MWs a unique band structure,as well as abundant trap states and defect levels,which enable them to acquire better photoresponse performance.This configuration of RPP-MWs provides a new idea for the design and application of novel heterostructures.展开更多
Ionic gels can be potentially used in wearable devices owing to their high humidity resistance and non-volatility.However,the applicability of existing ionic gel pressure sensors is limited by their low sensitivity.Th...Ionic gels can be potentially used in wearable devices owing to their high humidity resistance and non-volatility.However,the applicability of existing ionic gel pressure sensors is limited by their low sensitivity.Therefore,it is very import-ant to develop an ionic gel pressure sensor with high sensitivity and a wide pressure detection range without sacrificing mechan-ical stretchability and self-healing ability.Herein,we report an effective strategy for developing pressure sensors based on ion-ic gel composites consisting of high-molecular-weight polymers,ionic liquids,and Au nanoparticles.The resulting capacitive pressure sensors exhibit high pressure sensitivity,fast response,and excellent self-healing properties.The sensors composed of highly hydrophobic polymers and ionic liquids can be used to track underwater movements,demonstrating broad application prospects in human motion state monitoring and underwater mechanical operations.展开更多
Angle-resolved polarized Raman(ARPR) spectroscopy can be utilized to assign the Raman modes based on crystal symmetry and Raman selection rules and also to characterize the crystallographic orientation of anisotropi...Angle-resolved polarized Raman(ARPR) spectroscopy can be utilized to assign the Raman modes based on crystal symmetry and Raman selection rules and also to characterize the crystallographic orientation of anisotropic materials.However, polarized Raman measurements can be implemented by several different configurations and thus lead to different results. In this work, we systematically analyze three typical polarization configurations: 1) to change the polarization of the incident laser, 2) to rotate the sample, and 3) to set a half-wave plate in the common optical path of incident laser and scattered Raman signal to simultaneously vary their polarization directions. We provide a general approach of polarization analysis on the Raman intensity under the three polarization configurations and demonstrate that the latter two cases are equivalent to each other. Because the basal plane of highly ordered pyrolytic graphite(HOPG) exhibits isotropic feature and its edge plane is highly anisotropic, HOPG can be treated as a modelling system to study ARPR spectroscopy of twodimensional materials on their basal and edge planes. Therefore, we verify the ARPR behaviors of HOPG on its basal and edge planes at three different polarization configurations. The orientation direction of HOPG edge plane can be accurately determined by the angle-resolved polarization-dependent G mode intensity without rotating sample, which shows potential application for orientation determination of other anisotropic and vertically standing two-dimensional materials and other materials.展开更多
Nanofibers/nanowires with one-dimension(1D)nanostructure or well-patterned microstructure have shown distinctly advantages in flexible and stretchable sensor fields,owing to their remarkable tolerance against mechanic...Nanofibers/nanowires with one-dimension(1D)nanostructure or well-patterned microstructure have shown distinctly advantages in flexible and stretchable sensor fields,owing to their remarkable tolerance against mechanical bending or stretching,outstanding electronic/optoelectronic properties,good transparency,and excellent geometry.Herein,latest summaries in the unique structure and properties of nanofiber/nanowire function materials and their applications for flexible and stretchable sensor are highlighted.Several types of high-performance nanofiber/nanowire-based flexible pressure and stretchable sensors are also reviewed.Finally,a conclusion and prospect for 1D nanofiber/nanowires-based flexible and stretchable sensors are also intensively discussed.This summary offers new insights for the development of flexible and stretchable sensor based 1D nanostructure in next-generation flexible electronics.展开更多
Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimiz...Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.展开更多
Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method.As-synthesized SnS nanowires are single crystals grown along the[111]direction.The single SnS nanowire based device showed excellen...Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method.As-synthesized SnS nanowires are single crystals grown along the[111]direction.The single SnS nanowire based device showed excellent response to near infrared lights with good responsivity of 267.9 A/W,high external quantum efficiency of 3.12×10^4%and fast response time.Photodetectors were built on the aligned SnS nanowire arrays,exhibiting a light on/off ratio of 3.6,and the response and decay time of 4.5 and 0.7 s,respectively,to 1064 nm light illumination.展开更多
We investigate the influence of strain and electric field on the properties of a silicane sheet. Some elastic parameters of silicane, such as an in-plane stiffness of 52.55 N/m and a Poisson’s ratio of 0.24, are obta...We investigate the influence of strain and electric field on the properties of a silicane sheet. Some elastic parameters of silicane, such as an in-plane stiffness of 52.55 N/m and a Poisson’s ratio of 0.24, are obtained by calculating the strain energy. Compared with silicene, silicane is softer because of its relatively weaker Si–Si bonds. The band structure of silicane is tunable by a uniform tensile strain, with the increase of which the band gap decreases monotonously. Moreover, silicane undergoes an indirect–direct gap transition under a small strain, and a semiconductor–metal transition under a large strain. The electric field can change the Si–H bond length of silicane significantly. When a strong field is applied, the H atom at the high potential side becomes desorbed, while the H atom at the low potential side keeps bonded. So an external electric field can help to produce single-side hydrogenated silicene from silicane. We believe this study will be helpful for the application of silicane in the future.展开更多
Coherent tunnelling is studied in the framework of the effective mass approximation for an asymmetric coupled quantum well. The Hartree potential due to the electron-electron interaction is considered in our calculati...Coherent tunnelling is studied in the framework of the effective mass approximation for an asymmetric coupled quantum well. The Hartree potential due to the electron-electron interaction is considered in our calculation. The effects of the longitudinal and transverse magnetic field on coherent tunnelling characteristics are discussed. It has been found that the external field plays an important role in modulating the electron states.展开更多
The electronic structures of coupled quantum dots grown on (11N)-oriented substrates are studied in the framework of effective-mass envelope-function theory. The results show that the all-hole subbands have the smal...The electronic structures of coupled quantum dots grown on (11N)-oriented substrates are studied in the framework of effective-mass envelope-function theory. The results show that the all-hole subbands have the smallest widths and the optical properties are best for the (113), (114), and (115) growth directions. Our theoretical results agree with the available experimental data. Our calculated results are useful for the application of coupled quantum dots in photoelectric devices.展开更多
基金supported by National Natural Science Foundation of China(51672308,51972025,61888102,and 62004187).
文摘Two-dimension(2D)van der Waals heterojunction holds essential promise in achieving high-performance flexible near-infrared(NIR)photodetector.Here,we report the successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene based flexible NIR photodetector array via a facile photolithography technology.The single ZnSb/Ti_(3)C_(2)T_(x)photodetector exhibited a high light-to-dark current ratio of 4.98,fast response/recovery time(2.5/1.3 s)and excellent stability due to the tight connection between 2D ZnSb nanoplates and 2D Ti_(3)C_(2)T_(x)MXene nanoflakes,and the formed 2D van der Waals heterojunction.Thin polyethylene terephthalate(PET)substrate enables the ZnSb/Ti_(3)C_(2)T_(x)photodetector withstand bending such that stable photoelectrical properties with non-obvious change were maintained over 5000 bending cycles.Moreover,the ZnSb/Ti_(3)C_(2)T_(x)photodetectors were integrated into a 26×5 device array,realizing a NIR image sensing application.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB643903,2013CB932904,2012CB932701 and 2011CB922201the National Special Funds for the Development of Major Research Equipment and Instruments of China under Grant No 2012YQ140005+7 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB01010200the China Postdoctoral Science Foundation-funded Project under Grant No 2014M561029the Program for New Century Excellent Talents in University under Grant No NCET-10-0066the National High-Technology Research and Development Program of China under Grant No 2013AA031502the Science and Technology Innovation Project of Harbin City under Grant No2011RFLXG006the National Natural Science Foundation of China under Grant Nos 61274013,U1037602,61306013,51202046,and 61290303the China Postdoctoral Science Foundation under Grant Nos 2012M510144 and 2013T60366the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2013006 and HIT.BRETIII.201403
文摘We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave (MW), long-wave (LW), and very long-wave (VLW) detections. The detector structure consists of three contacts of NIPIN architecture for MW and LW detections, and hetero-junction NIP architecture for VLW detection. It is found that the spectral crosstalks can be significantly reduced by controlling the minority carriers transport via doping beryllium in the two active regions of NIPIN section. The crosstalk detection at MW, LW, and VLW signals are achieved by selecting the bias voltages on the device. At 77K, the cutoff wavelengths of the three-color detection are 5.3μm (at OmV), 141μm (at 300mV) and 19μm (at -20mV) with the detectivities of 4.6xlO11 cm.Hzl/ZW-1, 2.3×10^10 cm.Hzl/2W-1, and 1.0×10^10cm.Hzl/2W-1 for MW, LW and VLW. The crosstalks of the MW channel, LW channel, and VLW channel are almost 0, 0.25, and 0.6, respectively.
基金support from the National Natural Science Foundation of China(No.62174152)。
文摘Sweat loss monitoring is important for understanding the body’s thermoregulation and hydration status,as well as for comprehensive sweat analysis.Despite recent advances,developing a low-cost,scalable,and universal method for the fabrication of colorimetric microfluidics designed for sweat loss monitoring remains challenging.In this study,we propose a novel laserengraved surface roughening strategy for various flexible substrates.This process permits the construction of microchannels that show distinct structural reflectance changes before and after sweat filling.By leveraging these unique optical properties,we have developed a fully laser-engraved microfluidic device for the quantification of naked-eye sweat loss.This sweat loss sensor is capable of a volume resolution of 0.5µL and a total volume capacity of 11µL,and can be customized to meet different performance requirements.Moreover,we report the development of a crosstalk-free dual-mode sweat microfluidic system that integrates an Ag/AgCl chloride sensor and a matching wireless measurement flexible printed circuit board.This integrated system enables the real-time monitoring of colorimetric sweat loss signals and potential ion concentration signals without crosstalk.Finally,we demonstrate the potential practical use of this microfluidic sweat loss sensor and its integrated system for sports medicine via on-body studies.
基金the National Key Technologies R&D Program of China(Grant Nos.2019YFA0705203 and 2018YFA0209104)Major Program of the National Natural Science Foundation of China(Grant No.61790581)Aeronautical Science Foundation of China(Grant No.20182436004).
文摘High performance short-wavelength infrared PBn photodetectors based on InAs/GaSb/AlSb superlattices on GaSb substrate have been demonstrated.At 300 K,the device exhibits a 50%cut-off wavelength of~2.1μm as predicted from the band structure calculation;the device responsivity peaks at 0.85 A/W,corresponding to a quantum efficiency(QE)of 56%for 2.0μm-thick absorption region.The dark current density of 1.03×10^(-3)A/cm^(2)is obtained under 50 mV applied bias.The device exhibits a saturated dark current shot noise limited specific detectivity(D*)of 3.29×1010cm·Hz^(1/2)/W(at a peak responsivity of 2.0μm)under-50 mV applied bias.
基金supported primarily by the National Natural Science Foundation of China(Contract No.21975245,51972300,62274155,and U20A20206)the National Key Research and Development Program of China(Grant No.2018YFE0204000)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB43000000)the National Natural Science Foundation of China under Grant No.62175231.Prof.Kong Liu appreciates the support from the Youth Innovation Promotion Association,the Chinese Academy of Sciences(No.2020114)the Beijing Nova Program(No.2020117).
文摘Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61790580 and 61435012)the National Basic Research Program of China(Grant No.2014CB643903)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.YJKYYQ20170032)
文摘InGaSb/AlGaAsSb double-quantum-well diode lasers emitting around 2 μm are demonstrated. The AlGaAsSb barriers of the lasers are grown with digital alloy techniques consisting of binary AlSb/AlAs/GaSb short-period pairs. Peak power conversion efficiency of 26% and an efficiency higher than 16% at 1 W are achieved at continuous-wave operation for a 2-mm-long and 100-μm-wide stripe laser. The maximum output power of a single emitter reaches to 1.4 W at 7 A.19-emitter bars with maximum efficiency higher than 20% and maximum power of 16 W are fabricated. Lasers with the short-period-pair barriers are proved to have improved temperature properties and wavelength stabilities. The characteristic temperature(T_0) is up to 140?C near room temperature(25–55?C).
基金Supported by the National Natural Science Foundation of China under Grant No 60625405, and the National Basic Research Program of China under Grant Nos 2007CB936304 and 2010CB327601.
文摘InAs/GaSb superlattiee (SL) midwave infrared photovoltaic detectors are grown by molecular beam epitaxy on GaSb(001) residud p-type substrates. A thick GaSb layer is grown under the optimized growth condition as a buffer layer. The detectors containing a 320-period 8ML/SML InAs/GaS5 SL active layer are fabricated with a series pixel area using anode sulfide passivation. Corresponding to 50% cutoff wavelengths of 5.0 μm at 77K, the peak directivity of the detectors is 1.6 × 10^10 cm.Hz^1/2 W^-1 at 77K.
基金the National Natural Science Foundation of China(NSFC Grant No.62174152).
文摘To prevent and mitigate environmental degradation,high-performance and cost-effective electrochemical flexible energy storage systems need to be urgently developed.This demand has led to an increase in research on electrode materials for high-capacity flexible supercapacitors and secondary batteries,which have greatly aided the development of contemporary digital communications and electric vehicles.The use of layered double hydroxides(LDHs)as electrode materials has shown productive results over the last decade,owing to their easy production,versatile composition,low cost,and excellent physicochemical features.This review highlights the distinctive 2D sheet-like structures and electrochemical characteristics of LDH materials,as well as current developments in their fabrication strategies for expanding the application scope of LDHs as electrode materials for flexible supercapacitors and alkali metal(Li,Na,K)ion batteries.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA0301202)the National Natural Science Foundation of China(Grant No.61674135)
文摘Uniaxial stress is a powerful tool for tuning exciton emitting wavelength, polarization, fine-structure splitting (FSS), and the symmetry of quantum dots (QDs). Here, we present a technique for applying uniaxial stress, which enables us in situ to tune exciton optical properties at low temperature down to 15 K with high tuning precision. The design and operation of the device are described in detail. This technique provides a simple and convenient approach to tune QD structural symmetry, exciton energy and biexciton binding energy. It can be utilized for generating entangled and indistinguishable photons. Moreover, this device can be employed for tuning optical properties of thin film materials at low temperature.
基金Project supported by the Advanced Research Foundation of China(Grant No.914xxx803-051xxx111)the National Defense Advanced Research Project of China(Grant No.315xxxxx301)the National Defense Innovation Program of China(Grant No.48xx4)
文摘In this report, the effect of temperature on the In As/Al Sb heterojunction and high-electron-mobility transistors(HEMTs) with a gate length of 2 μm are discussed comprehensively. The results indicate that device performance is greatly improved at cryogenic temperatures. It is also observed that the device performance at 90 K is significantly improved with 27% lower gate leakage current, 12% higher maximum drain current, and 22.5% higher peak transconductance compared to 300 K. The temperature dependence of mobility and the two-dimensional electron gas concentration in the In As/Al Sb heterojunction for the temperature range 90 K-300 K is also investigated. The electron mobility at 90 K(42560 cm2/V·s)is 2.5 times higher than its value at 300 K(16911 cm^2/V·s) because of the weaker lattice vibration and the impurity ionization at cryogenic temperatures, which corresponds to a reduced scattering rate and higher mobility. We also noted that the two-dimensional electron gas concentration decreases slightly from 1.99 × 10^(12) cm^(-2) at 300 K to 1.7 × 10^(12) cm^(-2) at 90 K with a decrease in temperature due to the lower ionization at cryogenic temperature and the nearly constant ?Ec.
基金Project supported by the National Natural Science Foundation of China (Grant No 60625405)the Special Foundation forState Major Basic Research Program of China (Grant No 2006CB921504)
文摘We develop a modified two-step method of growing high-density and narrow size-distribution InAs/GaAs quantum dots (QDs) by molecular beam epitaxy. In the first step, high-density small InAs QDs are formed by optimizing the continuous deposition amount. In the second step, deposition is carried out with a long growth interruption for every 0.1 InAs monolayer. Atomic force microscope images show that the high-density (~5.9 × 10^11 cm^-2) good size-uniformity InAs QDs are achieved. The strong intensity and narrow linewidth (27.7 meV) of the photoluminescence spectrum show that the QDs grown in this two-step method have a good optical quality.
基金This work was supported by the National Science Foundation of China(NSFC),(Grant No.62022079)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2020115).
文摘Recently,the two-dimensional(2D)form of Ruddlesden-Popper perovskite(RPP)has been widely studied.However,the synthesis of one-dimensional(1D)RPP is rarely reported.Here,we fabricated a photodetector based on RPP microwires(RPP-MWs)and compared it with a 2D-RPP photodetector.The results show that the RPP-MWs photodetector possesses a wider photoresponse range and higher responsivities of 233 A/W in the visible band and 30 A/W in the near-infrared(NIR)band.The analyses show that the synthesized RPP-MWs have a multi-layer,heterogeneous core-shell structure.This structure gives RPP-MWs a unique band structure,as well as abundant trap states and defect levels,which enable them to acquire better photoresponse performance.This configuration of RPP-MWs provides a new idea for the design and application of novel heterostructures.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.61874111,62174152 and 62022079)the National Key Research and Development Program of China(Grant No.2020YFB1506400)+1 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020115)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16021200).
文摘Ionic gels can be potentially used in wearable devices owing to their high humidity resistance and non-volatility.However,the applicability of existing ionic gel pressure sensors is limited by their low sensitivity.Therefore,it is very import-ant to develop an ionic gel pressure sensor with high sensitivity and a wide pressure detection range without sacrificing mechan-ical stretchability and self-healing ability.Herein,we report an effective strategy for developing pressure sensors based on ion-ic gel composites consisting of high-molecular-weight polymers,ionic liquids,and Au nanoparticles.The resulting capacitive pressure sensors exhibit high pressure sensitivity,fast response,and excellent self-healing properties.The sensors composed of highly hydrophobic polymers and ionic liquids can be used to track underwater movements,demonstrating broad application prospects in human motion state monitoring and underwater mechanical operations.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA0301204)the National Natural Science Foundation of China(Grant Nos.11604326,11434010,11474277,and 11225421)
文摘Angle-resolved polarized Raman(ARPR) spectroscopy can be utilized to assign the Raman modes based on crystal symmetry and Raman selection rules and also to characterize the crystallographic orientation of anisotropic materials.However, polarized Raman measurements can be implemented by several different configurations and thus lead to different results. In this work, we systematically analyze three typical polarization configurations: 1) to change the polarization of the incident laser, 2) to rotate the sample, and 3) to set a half-wave plate in the common optical path of incident laser and scattered Raman signal to simultaneously vary their polarization directions. We provide a general approach of polarization analysis on the Raman intensity under the three polarization configurations and demonstrate that the latter two cases are equivalent to each other. Because the basal plane of highly ordered pyrolytic graphite(HOPG) exhibits isotropic feature and its edge plane is highly anisotropic, HOPG can be treated as a modelling system to study ARPR spectroscopy of twodimensional materials on their basal and edge planes. Therefore, we verify the ARPR behaviors of HOPG on its basal and edge planes at three different polarization configurations. The orientation direction of HOPG edge plane can be accurately determined by the angle-resolved polarization-dependent G mode intensity without rotating sample, which shows potential application for orientation determination of other anisotropic and vertically standing two-dimensional materials and other materials.
基金National Natural Science Foundation of China(NSFC Grant No.61625404)the Science and Technology Development Plan of Jilin Province(20190103135JH)Young Elite Scientists Sponsorship Program by CAST(2018QNRC001).
文摘Nanofibers/nanowires with one-dimension(1D)nanostructure or well-patterned microstructure have shown distinctly advantages in flexible and stretchable sensor fields,owing to their remarkable tolerance against mechanical bending or stretching,outstanding electronic/optoelectronic properties,good transparency,and excellent geometry.Herein,latest summaries in the unique structure and properties of nanofiber/nanowire function materials and their applications for flexible and stretchable sensor are highlighted.Several types of high-performance nanofiber/nanowire-based flexible pressure and stretchable sensors are also reviewed.Finally,a conclusion and prospect for 1D nanofiber/nanowires-based flexible and stretchable sensors are also intensively discussed.This summary offers new insights for the development of flexible and stretchable sensor based 1D nanostructure in next-generation flexible electronics.
基金This work was supported by National Natural Science Foundation of China(51672308,51972025,61888102,62004187)Hebei Natural Science Foundation of Hebei(E2019208280).
文摘Zinc-ion hybrid fiber supercapacitors(FSCs)are promising energy storages for wearable electronics owing to their high energy density,good flexibility,and weavability.However,it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs.Herein,we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti_(3)C_(2)T_x MXene cathode as core electrodes,and shell zinc fiber anode was braided on the surface of the Ti_(3)C_(2)T_x MXene fibers across the solid electrolytes.According to the simulated results using ANSYS Maxwell software,the braided structures revealed a higher capacitance compared to the spring-like structures.The resulting FSCs exhibited a high areal capacitance of 214 mF cm^(-2),the energy density of 42.8μWh cm^(-2)at 5 mV s^(-1),and excellent cycling stability with 83.58%capacity retention after 5000 cycles.The coaxial FSC was tied several kinds of knots,proving a shape-controllable fiber energy storage.Furthermore,the knitted FSC showed superior stability and weavability,which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.
基金National Natural Science Foundation of China(61625404,61888102).
文摘Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method.As-synthesized SnS nanowires are single crystals grown along the[111]direction.The single SnS nanowire based device showed excellent response to near infrared lights with good responsivity of 267.9 A/W,high external quantum efficiency of 3.12×10^4%and fast response time.Photodetectors were built on the aligned SnS nanowire arrays,exhibiting a light on/off ratio of 3.6,and the response and decay time of 4.5 and 0.7 s,respectively,to 1064 nm light illumination.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60925016)
文摘We investigate the influence of strain and electric field on the properties of a silicane sheet. Some elastic parameters of silicane, such as an in-plane stiffness of 52.55 N/m and a Poisson’s ratio of 0.24, are obtained by calculating the strain energy. Compared with silicene, silicane is softer because of its relatively weaker Si–Si bonds. The band structure of silicane is tunable by a uniform tensile strain, with the increase of which the band gap decreases monotonously. Moreover, silicane undergoes an indirect–direct gap transition under a small strain, and a semiconductor–metal transition under a large strain. The electric field can change the Si–H bond length of silicane significantly. When a strong field is applied, the H atom at the high potential side becomes desorbed, while the H atom at the low potential side keeps bonded. So an external electric field can help to produce single-side hydrogenated silicene from silicane. We believe this study will be helpful for the application of silicane in the future.
基金Supported by the National Natural Science Foundation of China under Grant No 60521001.
文摘Coherent tunnelling is studied in the framework of the effective mass approximation for an asymmetric coupled quantum well. The Hartree potential due to the electron-electron interaction is considered in our calculation. The effects of the longitudinal and transverse magnetic field on coherent tunnelling characteristics are discussed. It has been found that the external field plays an important role in modulating the electron states.
基金Project supported in part by the National Natural Science Foundation of China (Grant Nos 60521001 and 60325416).
文摘The electronic structures of coupled quantum dots grown on (11N)-oriented substrates are studied in the framework of effective-mass envelope-function theory. The results show that the all-hole subbands have the smallest widths and the optical properties are best for the (113), (114), and (115) growth directions. Our theoretical results agree with the available experimental data. Our calculated results are useful for the application of coupled quantum dots in photoelectric devices.