We calculate the electronic properties and carrier mobility of perovskite CH3NH3SnI3as a solar cell absorber by using the hybrid functional method. The calculated result shows that the electron and hole mobilities hav...We calculate the electronic properties and carrier mobility of perovskite CH3NH3SnI3as a solar cell absorber by using the hybrid functional method. The calculated result shows that the electron and hole mobilities have anisotropies with a large magnitude of 1.4 × 104cm2·V-1·s-1along the y direction. In view of the huge difference between hole and electron mobilities, the perovskite CH3NH3 Sn I3can be considered as a p-type semiconductor. We also discover a relationship between the effective mass anisotropy and electronic occupation anisotropy. The above results can provide reliable guidance for its experimental applications in electronics and optoelectronics.展开更多
Highly epitaxial YBa2Cu3O7-δ （YBCO） and yttria-stabilized zirconia （YSZ） bilayer thin films have been deposited on silicon-on-insulator （SOI） substrates by using in situ pulsed laser deposition （PLD） techniqu...Highly epitaxial YBa2Cu3O7-δ （YBCO） and yttria-stabilized zirconia （YSZ） bilayer thin films have been deposited on silicon-on-insulator （SOI） substrates by using in situ pulsed laser deposition （PLD） technique. In the experiment, the native amorphous SiO2 layers on some of the SOI substrates are removed by dipping them in a 10% HF solution for 15 s. Comparing several qualities of films grown on substrates with or without HF pretreatment, such as thin film crystallinity, general surface roughness, temperature dependence of resistance, surface morphology, as well as average crack spacing and crack width, naturally leads to the conclusion that preserving the native SiO2 layer on the surface of the SOI substrate can not only simplify the experimental process but can also achieve fairly high quality YSZ and YBCO thin films.展开更多
The present paper discusses our investigation of InGaAs surface morphology annealed for different lengths of time.After annealing for 15 min,the ripening of InGaAs islands is completed.The real space scanning tunnelin...The present paper discusses our investigation of InGaAs surface morphology annealed for different lengths of time.After annealing for 15 min,the ripening of InGaAs islands is completed.The real space scanning tunneling microscopy（STM） images show the evolution of InGaAs surface morphology.A half-terrace diffusion theoretical model based on thermodynamic theory is proposed to estimate the annealing time for obtaining flat morphology.The annealing time calculated by the proposed theory is in agreement with the experimental results.展开更多
The toxicity and degradation of hybrid lead-halide perovskites hinder their extensive applications.It is thus of great importance to explore non-toxic alternative materials with excellent stability and optoelectronic ...The toxicity and degradation of hybrid lead-halide perovskites hinder their extensive applications.It is thus of great importance to explore non-toxic alternative materials with excellent stability and optoelectronic property.We investigate the atomic structures and optoelectronic properties of non-toxic organic tin bromide perovskites(OTBP)with one/zerodimensional(1D/0D)structures by first-principles calculations.The calculated atomic structures show that the 1D/0D OTBPs are stable and the structure of inorganic octahedra in 0D is higher order than that in 1D.Moreover,the origination of exceptional purity emitting light in experiments is explained based on the calculated electronic structure.展开更多
Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-opti...Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching.Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay.The fabricated OTLDs show an ultra-low propagation loss of^0.03dB/cm for waveguide lengths well above 100 cm.展开更多
Surface segregation is studied via the evolution of reflection high-energy electron diffraction （RHEED） patterns under different values of As4 BEP for InGaAs films. When the As4 BEP is set to be zero, the RHEED patt...Surface segregation is studied via the evolution of reflection high-energy electron diffraction （RHEED） patterns under different values of As4 BEP for InGaAs films. When the As4 BEP is set to be zero, the RHEED pattern keeps a 4x3/（nx3） structure with increasing temperature, and surface segregation takes place until 470 ℃ The RHEED pattern develops into a metal-rich （4x2） structure as temperature increases to 495℃. The reason for this is that surface segregation makes the In inside the InGaAs film climb to its surface. With the temperature increasing up to 515℃, the RHEED pattern turns into a GaAs（2x4） structure due to In desorption. While the As4 BEP comes up to a specific value （1.33 x 10-4 Pa-1.33 x 10-3 Pa）, the surface temperature can delay the segregation and desorption. We find that As4 BEP has a big influence on surface desorption, while surface segregation is more strongly dependent on temperature than surface desorption.展开更多
To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system...To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system.In the SSTF scheme,we propose a pulse compensation scheme for the fiber laser with a narrow spectral bandwidth by building an extra-cavity pulse stretcher.We further demonstrate truly 3D isotropic microfabrication in photosensitive glass with a tunable resolution ranging from 8μm to 22μm using the SSTF of fs laser pulses.Moreover,we systematically investigate the influences of pulse energy,writing speed,processing depth,and spherical aberration on the fabrication resolution.As a proof-of-concept demonstration,the SSTF scheme was further employed for the fs laser-assisted etching of complicated glass microfluidic structures with 3D uniform sizes.The developed technique can be extended to many applications such as advanced photonics,3D biomimetic printing,micro-electromechanical systems,and lab-on-a-chips.展开更多
Developing high-efficiency and stable inverted CsPbI2Br perovskite solar cells is vitally urgent for their unique advantages of removing adverse dopants and compatible process with tandem cells in comparison with the ...Developing high-efficiency and stable inverted CsPbI2Br perovskite solar cells is vitally urgent for their unique advantages of removing adverse dopants and compatible process with tandem cells in comparison with the regular.However,relatively low opening circuit voltage(Voc)and limited moisture stability have lagged their progress far from the regular.Here,we propose an effective surface treatment strategy with high-temperature FABr treatment to address these issues.The induced ions exchange can not only adjust energy level,but also gift effective passivation.Meanwhile,the gradient distribution of FA+can accelerate the carriers transport to further suppress bulk recombination.Besides,the Br-rich surface and FA+substitution can isolate moisture erosions.As a result,the optimized devices show champion efficiency of 15.92%with Voc of 1.223 V.In addition,the tolerance of humidity and operation get significant promotion:maintaining 91.7%efficiency after aged at RH 20%ambient condition for 1300 h and 81.8%via maximum power point tracking at 45°C for 500 h in N2.Furthermore,the unpackaged devices realize the rare reported air operational stability and,respectively,remain almost efficiency(98.9%)after operated under RH 35%for 600 min and 91.2%under RH 50%for 300 min.展开更多
We theoretically investigated a second-order optomechanical-induced transparency(OMIT) process of a hybrid optomechanical system(COMS), which a Bose-Einstein condensate(BEC) in the presence of atom-atom interaction tr...We theoretically investigated a second-order optomechanical-induced transparency(OMIT) process of a hybrid optomechanical system(COMS), which a Bose-Einstein condensate(BEC) in the presence of atom-atom interaction trapped inside a cavity with a moving end mirror. The advantage of this hybrid COMS over a bare COMS is that the frequency of the second mode is controlled by the s-wave scattering interaction. Based on the traditional linearization approximation, we derive analytical solutions for the output transmission intensity of the probe field and the dimensionless amplitude of the second-order sideband(SS). The numerical results show that the transmission intensity of the probe field and the dimensionless amplitude of the SS can be controlled by the s-wave scattering frequency. Furthermore, the control field intensities,the effective detuning, the effective coupling strength of the cavity field with the Bogoliubov mode are used to control the transmission intensity of the probe field and the dimensionless amplitude of the SS.展开更多
Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through soluti...Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.展开更多
In this paper,small diameter InP nanowires with high crystal quality were synthesized through a chemical vapor deposition method.Benefitting from the high crystallinity and large specific surface area of InP nanowires...In this paper,small diameter InP nanowires with high crystal quality were synthesized through a chemical vapor deposition method.Benefitting from the high crystallinity and large specific surface area of InP nanowires,the simply constructed photodetector demonstrates a high responsivity of up to 1170 A·W （-1） and an external quantum efficiency of2.8 × 10 5% with a fast rise time of 110 ms and a fall time of 130 ms,even at low bias of 0.1 V.The effect of back-gate voltage on photoresponse of the device was systematically investigated,confirming that the photocurrent dominates over thermionic and tunneling currents in the whole operation.A mechanism based on energy band theory at the junction between metal and semiconductor was proposed to explain the back-gate voltage dependent performance of the photodetectors.These convincing results indicate that fine InP nanowires will have a brilliant future in smart optoelectronics.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51172067)the Hunan Provincial Natural Science Fund for Distinguished Young Scholars,China(Grant No.13JJ1013)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20130161110036)the New Century Excellent Talents in University,China(Grant No.NCET-12-0171.D)
文摘We calculate the electronic properties and carrier mobility of perovskite CH3NH3SnI3as a solar cell absorber by using the hybrid functional method. The calculated result shows that the electron and hole mobilities have anisotropies with a large magnitude of 1.4 × 104cm2·V-1·s-1along the y direction. In view of the huge difference between hole and electron mobilities, the perovskite CH3NH3 Sn I3can be considered as a p-type semiconductor. We also discover a relationship between the effective mass anisotropy and electronic occupation anisotropy. The above results can provide reliable guidance for its experimental applications in electronics and optoelectronics.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50672125 and 10574154)the Natural Science Foundation of Shanxi Province, China (Grant No 2009011003-1)the Youth Foundation of Shanxi Datong University, China (Grant No 2007Q10)
文摘Highly epitaxial YBa2Cu3O7-δ （YBCO） and yttria-stabilized zirconia （YSZ） bilayer thin films have been deposited on silicon-on-insulator （SOI） substrates by using in situ pulsed laser deposition （PLD） technique. In the experiment, the native amorphous SiO2 layers on some of the SOI substrates are removed by dipping them in a 10% HF solution for 15 s. Comparing several qualities of films grown on substrates with or without HF pretreatment, such as thin film crystallinity, general surface roughness, temperature dependence of resistance, surface morphology, as well as average crack spacing and crack width, naturally leads to the conclusion that preserving the native SiO2 layer on the surface of the SOI substrate can not only simplify the experimental process but can also achieve fairly high quality YSZ and YBCO thin films.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60866001 and 61076049)the Science and Technology Projects for Overseas Researchers of Guizhou Province (Grant No. (2007) 03)+5 种基金the Foundation of Guizhou Provincial Science and Technology Department (Grant No. QKH-J[2007]2176)the Special Assistant to the High-Level Personnel Research Projects of Guizhou Provincial Committee,Organization Department(Grant No. TZJF-200610)the Doctorate Foundation of the Education Ministry of China (Grant No. 20105201110003)the Science and Technology Projects for Overseas Researchers of Guizhou Province (Grant No. Z103233)Special Governor Fund for Outstanding Professionals in Science & Technology and Education of Guizhou Province (Grant No. 2009114)the Innovation Funds for Graduates of Guizhou University (Grant No. LG2012019)
文摘The present paper discusses our investigation of InGaAs surface morphology annealed for different lengths of time.After annealing for 15 min,the ripening of InGaAs islands is completed.The real space scanning tunneling microscopy（STM） images show the evolution of InGaAs surface morphology.A half-terrace diffusion theoretical model based on thermodynamic theory is proposed to estimate the annealing time for obtaining flat morphology.The annealing time calculated by the proposed theory is in agreement with the experimental results.
基金Project supported by the National Natural Science Foundation of China(Grant No.51972102).
文摘The toxicity and degradation of hybrid lead-halide perovskites hinder their extensive applications.It is thus of great importance to explore non-toxic alternative materials with excellent stability and optoelectronic property.We investigate the atomic structures and optoelectronic properties of non-toxic organic tin bromide perovskites(OTBP)with one/zerodimensional(1D/0D)structures by first-principles calculations.The calculated atomic structures show that the 1D/0D OTBPs are stable and the structure of inorganic octahedra in 0D is higher order than that in 1D.Moreover,the origination of exceptional purity emitting light in experiments is explained based on the calculated electronic structure.
基金Supported by the National Key R&D Program of China(Grant No.2019YFA0705000)the National Natural Science Foundation of China(Grant Nos.11734009,61590934,and 11874375)+1 种基金the Strategic Priority Research Program of CAS(Grant No.XDB16030300)the Key Project of the Shanghai Science and Technology Committee(Grant No.17JC1400400).
文摘Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching.Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay.The fabricated OTLDs show an ultra-low propagation loss of^0.03dB/cm for waveguide lengths well above 100 cm.
基金supported by the National Natural Science Foundation of China (Grant No. 60866001)the Special Assistant to High-Level Personnel Research Projects of Guizhou Provincial Party Committee Organization Department of China (Grant No. TZJF- 2008-31)+3 种基金the Support Plan of New Century Excellent Talents of Ministry of Education, China (Grant No. NCET-08-0651)the Doctorate Foundation of the State Education Ministry of China (Grant No. 20105201110003)the Special Governor Fund of Outstanding Professionals in Science and Technology and Education of Guizhou Province, China (Grant No. 2009114)the Doctoral Foundation Projects of Guizhou College of Finance and Economics in 2010
文摘Surface segregation is studied via the evolution of reflection high-energy electron diffraction （RHEED） patterns under different values of As4 BEP for InGaAs films. When the As4 BEP is set to be zero, the RHEED pattern keeps a 4x3/（nx3） structure with increasing temperature, and surface segregation takes place until 470 ℃ The RHEED pattern develops into a metal-rich （4x2） structure as temperature increases to 495℃. The reason for this is that surface segregation makes the In inside the InGaAs film climb to its surface. With the temperature increasing up to 515℃, the RHEED pattern turns into a GaAs（2x4） structure due to In desorption. While the As4 BEP comes up to a specific value （1.33 x 10-4 Pa-1.33 x 10-3 Pa）, the surface temperature can delay the segregation and desorption. We find that As4 BEP has a big influence on surface desorption, while surface segregation is more strongly dependent on temperature than surface desorption.
基金supported by the National Key Research and Development Program of China(2019YFA0705000,2022YFA1404800)National Natural Science Foundation of China(12004221,12174107,12192254,11734009,12192251,92250304,11974218)+4 种基金Postdoctoral Innovation Talents Support Program of Shandong Province(No.SDBX2019005)Science and Technology Commission of Shanghai Municipality(21DZ1101500)Local science and technology development project of the central government(YDZX20203700001766)Shanghai Municipal Science and Technology Major ProjectNatural Science Foundation of Shandong Province(ZR2021ZD02).
文摘To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system.In the SSTF scheme,we propose a pulse compensation scheme for the fiber laser with a narrow spectral bandwidth by building an extra-cavity pulse stretcher.We further demonstrate truly 3D isotropic microfabrication in photosensitive glass with a tunable resolution ranging from 8μm to 22μm using the SSTF of fs laser pulses.Moreover,we systematically investigate the influences of pulse energy,writing speed,processing depth,and spherical aberration on the fabrication resolution.As a proof-of-concept demonstration,the SSTF scheme was further employed for the fs laser-assisted etching of complicated glass microfluidic structures with 3D uniform sizes.The developed technique can be extended to many applications such as advanced photonics,3D biomimetic printing,micro-electromechanical systems,and lab-on-a-chips.
基金The authors thank the financial supports by the National Natural Science Foundation of China(61974150 and 51773213)the Zhejiang Provincial Natural Science Foundation of China(LQ19E030008)+1 种基金the Key Research Program of Frontier Sciences,CAS(QYZDB-SSW-JSC047),the Zhejiang Province Science and Technology Plan(2018C01047)the Fundamental Research Funds for the Central Universities and the National Youth Top-notch Talent Support Program.
文摘Developing high-efficiency and stable inverted CsPbI2Br perovskite solar cells is vitally urgent for their unique advantages of removing adverse dopants and compatible process with tandem cells in comparison with the regular.However,relatively low opening circuit voltage(Voc)and limited moisture stability have lagged their progress far from the regular.Here,we propose an effective surface treatment strategy with high-temperature FABr treatment to address these issues.The induced ions exchange can not only adjust energy level,but also gift effective passivation.Meanwhile,the gradient distribution of FA+can accelerate the carriers transport to further suppress bulk recombination.Besides,the Br-rich surface and FA+substitution can isolate moisture erosions.As a result,the optimized devices show champion efficiency of 15.92%with Voc of 1.223 V.In addition,the tolerance of humidity and operation get significant promotion:maintaining 91.7%efficiency after aged at RH 20%ambient condition for 1300 h and 81.8%via maximum power point tracking at 45°C for 500 h in N2.Furthermore,the unpackaged devices realize the rare reported air operational stability and,respectively,remain almost efficiency(98.9%)after operated under RH 35%for 600 min and 91.2%under RH 50%for 300 min.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11564034 and 21663026)the Natural Science Foundation of Gansu Province, China (Grant No. 20JR5RA509)+1 种基金the Fundamental Research Funds for the Central Universities of College of Electrical Engineering, Northwest Minzu University (Grant Nos. 31920210016, 31920190006, and 31920200006)the Scientific Research Project of Hunan Educational Department, China (Grant No. 19B206)。
文摘We theoretically investigated a second-order optomechanical-induced transparency(OMIT) process of a hybrid optomechanical system(COMS), which a Bose-Einstein condensate(BEC) in the presence of atom-atom interaction trapped inside a cavity with a moving end mirror. The advantage of this hybrid COMS over a bare COMS is that the frequency of the second mode is controlled by the s-wave scattering interaction. Based on the traditional linearization approximation, we derive analytical solutions for the output transmission intensity of the probe field and the dimensionless amplitude of the second-order sideband(SS). The numerical results show that the transmission intensity of the probe field and the dimensionless amplitude of the SS can be controlled by the s-wave scattering frequency. Furthermore, the control field intensities,the effective detuning, the effective coupling strength of the cavity field with the Bogoliubov mode are used to control the transmission intensity of the probe field and the dimensionless amplitude of the SS.
基金The authors acknowledge funding from the National Natural Science Foundation of China(61974150 and 51773213)Key Research Program of Frontier Sciences,CAS(QYZDB-SSW-JSC047)+1 种基金the Fundamental Research Funds for the Central Universities,the CAS-EU S&T cooperation partner program(174433KYSB20150013)the Natural Science Foundation of Ningbo(2018A610135).
文摘Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51525202,61574051,61505051,and 61474040)the Science and Tecnnology Plan of Hunan Province,China(Grant Nos.2014FJ2001 and 2014TT1004)the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province,China
文摘In this paper,small diameter InP nanowires with high crystal quality were synthesized through a chemical vapor deposition method.Benefitting from the high crystallinity and large specific surface area of InP nanowires,the simply constructed photodetector demonstrates a high responsivity of up to 1170 A·W （-1） and an external quantum efficiency of2.8 × 10 5% with a fast rise time of 110 ms and a fall time of 130 ms,even at low bias of 0.1 V.The effect of back-gate voltage on photoresponse of the device was systematically investigated,confirming that the photocurrent dominates over thermionic and tunneling currents in the whole operation.A mechanism based on energy band theory at the junction between metal and semiconductor was proposed to explain the back-gate voltage dependent performance of the photodetectors.These convincing results indicate that fine InP nanowires will have a brilliant future in smart optoelectronics.
