Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport...Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.展开更多
The unique advantages of one-dimensional(1D)oriented nanostructures in light-trapping and chargetransport make them competitive candidates in photovoltaic(PV)devices.Since the emergence of perovskite solar cells(PSCs)...The unique advantages of one-dimensional(1D)oriented nanostructures in light-trapping and chargetransport make them competitive candidates in photovoltaic(PV)devices.Since the emergence of perovskite solar cells(PSCs),1D nanostructured electron transport materials(ETMs)have drawn tremendous interest.However,the power conversion efficiencies(PCEs)of these devices have always significantly lagged behind their mesoscopic and planar counterparts.High-efficiency PSCs with 1D ETMs showing efficiency over 22%were just realized in the most recent studies.It yet lacks a comprehensive review covering the development of 1D ETMs and their application in PSCs.We hence timely summarize the advances in 1D ETMs-based solar cells,emphasizing on the fundamental and optimization issues of charge separation and collection ability,and their influence on PV performance.After sketching the classification and requirements for high-efficiency 1D nanostructured solar cells,we highlight the applicability of 1D TiO_(2)nanostructures in PSCs,including nanotubes,nanorods,nanocones,and nanopyramids,and carefully analyze how the electrostatic field affects cell performance.Other kinds of oriented nanostructures,e.g.,ZnO and SnO_(2)ETMs,are also described.Finally,we discuss the challenges and propose some potential strategies to further boost device performance.This review provides a broad range of valuable work in this fast-developing field,which we hope will stimulate research enthusiasm to push PSCs to an unprecedented level.展开更多
Electron transport layer(ETL)is pivotal to charge carrier transport for PSCs to reach the Shockley-Queisser limit.This study provides a fundamental understanding of heterojunction electron transport layers(ETLs)at the...Electron transport layer(ETL)is pivotal to charge carrier transport for PSCs to reach the Shockley-Queisser limit.This study provides a fundamental understanding of heterojunction electron transport layers(ETLs)at the atomic level for stable and efficient perovskite solar cells(PSCs).The bilayer structure of an ETL composed of SnO_(2) on TiO_(2) was examined,revealing a critical factor limiting its potential to obtain efficient performance.Alteration of oxygen vacancies in the TiO_(2) underlayer via an annealing process is found to induce manipulated band offsets at the interface between the TiO_(2) and SnO_(2) layers.In-depth electronic investigations of the bilayer structure elucidate the importance of the electronic properties at the interface between the TiO_(2) and SnO_(2) layers.The apparent correlation in hysteresis phenomena,including current density-voltage(J-V)curves,appears as a function of the type of band alignment.Density functional theory calculations reveal the intimate relationship between oxygen vacancies,deep trap states,and charge transport efficiency at the interface between the TiO_(2) and SnO_(2) layers.The formation of cascade band alignment via control over the TiO_(2) underlayer enhances device performance and suppresses hysteresis.Optimal performance exhibits a power conversion efficiency(PCE)of 23.45%with an open-circuit voltage(V_(oc))of 1.184 V,showing better device stability under maximum power point tracking compared with a staggered bilayer under one-sun continuous illumination.展开更多
Electron transport layers(ETLs)are crucial for achieving efficient and stable planar perovskite solar cells(PSCs).Reports on versatile inorganic ETLs using a simple film fabrication method and applicability for both l...Electron transport layers(ETLs)are crucial for achieving efficient and stable planar perovskite solar cells(PSCs).Reports on versatile inorganic ETLs using a simple film fabrication method and applicability for both low-cost planar regular and inverted PSCs with excellent efficiencies(>22%)and high stability are very limited.Herein,we employ a novel inorganic ZnSe as ETL for both regular and inverted PSCs to improve the efficiency and stability using a simple thermal evaporation method.The TiO_(2)-ZnSe-FAPbl_(3)heterojunction could be formed,resulting in an improved charge collection and a decreased carrier recombination further proved through theoretical calculations.The optimized regular PSCs based on TiO_(2)/ZnSe have achieved 23.25%efficiency with negligible hysteresis.In addition,the ZnSe ETL can also effectively replace the unstable bathocuproine(BCP)in inverted PSCs.Consequently,the ZnSe-based inverted device realizes a champion efficiency of 22.54%.Moreover,the regular device comprising the TiO_(2)/ZnSe layers retains 92%of its initial PCE after 10:00 h under 1 Sun continuous illumination and the inverted device comprising the C_(60)/ZnSe layers maintains over 85%of its initial PCE at 85℃for 10:00 h.This highlights one of the best results among universal ETLs in both regular and inverted perovskite photovoltaics.展开更多
Evolution of an electrostatic plasma wave driven by a low-density ultra-relativistic electron beam in dense inhomogeneous plasma is considered. In particular, the wavelength variation as observed at fixed locations in...Evolution of an electrostatic plasma wave driven by a low-density ultra-relativistic electron beam in dense inhomogeneous plasma is considered. In particular, the wavelength variation as observed at fixed locations in the plasma is analyzed in terms of the wave characteristics. It is shown that for a negative density gradient, the observed local wavelength decreases monotonically with time, but for a positive density gradient, it first increases and then decreases with time, accompanied by reversal of the wave phase. However, in both cases the local wavelength eventually decreases with time since Landau damping becomes significant as the wavelength becomes of the order of the plasma Debye length. Results from particle-in-cell simulations agree well with theoretical analyses of the wavelength variation.展开更多
Highly-efficient oxidation of 5-hydroxymethylfurtural(HMF) to 2,5-furandicarboxylic acid(FDCA) at low temperature with air as the oxidant is still challenging.Herein,inspired by the respirato ry electron transport cha...Highly-efficient oxidation of 5-hydroxymethylfurtural(HMF) to 2,5-furandicarboxylic acid(FDCA) at low temperature with air as the oxidant is still challenging.Herein,inspired by the respirato ry electron transport chain(ETC) of living cells mediated by electron carriers,we constructed artificial ETCs and transformed liquid flow fuel cells(LFFCs) to flexible reactors for efficient oxidation of HMF to produce FDCA under mild conditions.This LFFC reactor employed an electrodeposition modified nickel foam as an anode to promote HMF oxidation and(VO_(2))_(2)SO_(4) as a cathode electron carrier to facilitate the electron transfer to air.The reaction rate could be easily controlled by selecting the anode catalyst,adjusting the external loading and changing the cathodic electron carrier or oxidants.A maximal power density of 44.9 mW cm^(-2) at room temperature was achieved,while for FDCA production,short-circuit condition was preferred to achieve quick transfer of electrons.For a single batch operation with 0.1 M initial HMF,FDCA yield reached 97.1%.By fed-batch operation,FDCA concentration reached 144.5 g L^(-1) with a total yield of 96%.Ni^(2+)/Ni^(3+) redox couple was the active species mediating the electron transfer,while both experimental and DFT calculation results indicated that HMFCA pathway was the preferred reaction mechanism.展开更多
Valleytronics materials are a kind of special semiconductors which can host multiple symmetry-connected and wellseparated electron or hole pockets in the Brillouin zone when the system is slightly n or p doped. Since ...Valleytronics materials are a kind of special semiconductors which can host multiple symmetry-connected and wellseparated electron or hole pockets in the Brillouin zone when the system is slightly n or p doped. Since the low-energy particles residing in these pockets generally are not easily scattered to each other by small perturbations, they are endowed with an additional valley degree of freedom. Analogous to spin, the valley freedom can be used to process information,leading to the concept of valleytronics. The prerequisite for valleytronics is the generation of valley polarization. Thus,a focus in this field is achieving the electric generation of valley polarization, especially the static generation by the gate electric field alone. In this work, we briefly review the latest progress in this research direction, focusing on the concepts of the couplings between valley and layer, i.e., the valley–layer coupling which permits the gate-field control of the valley polarization, the couplings between valley, layer, and spin in magnetic systems, the physical properties, the novel designing schemes for electronic devices, and the material realizations of the gate-controlled valleytronics materials.展开更多
The sluggish redox kinetics of polysulfides in lithium-sulfur(Li-S)batteries are a significant obstacle to their widespread adoption as energy storage devices.However,recent studies have shown that tungsten oxide(WO_(...The sluggish redox kinetics of polysulfides in lithium-sulfur(Li-S)batteries are a significant obstacle to their widespread adoption as energy storage devices.However,recent studies have shown that tungsten oxide(WO_(3))can facilitate the conversion kinetics of polysulfides in Li-S batteries.Herein,we fabricated host materials for sulfur using nitrogen-doped carbon nanotubes(N-CNTs)and WO_(3).We used low-cost components and simple procedures to overcome the poor electrical conductivity that is a disadvantage of metal oxides.The composites of WO_(3) and N-CNTs(WO_(3)/N-CNTs)create a stable framework structure,fast ion diffusion channels,and a 3D electron transport network during electrochemical reaction processes.As a result,the WO_(3)/N-CNT-Li2S6 cathode demonstrates high initial capacity(1162 mA·h·g^(-1) at 0.5℃),excellent rate performance(618 mA·h·g^(-1) at 5.5℃),and a low capacity decay rate(0.093%up to 600 cycles at 2℃).This work presents a novel approach for preparing tungsten oxide/carbon composite catalysts that facilitate the redox kinetics of polysulfide conversion.展开更多
Bismuthene,an inherently hexagonal structure characterized by a huge bulk gap,offers a versatile platform for investigating the electronic transport of various topological quantum states.Using nonequilibrium Green'...Bismuthene,an inherently hexagonal structure characterized by a huge bulk gap,offers a versatile platform for investigating the electronic transport of various topological quantum states.Using nonequilibrium Green's function method and Landauer-Büttiker formula,we thoroughly investigate the transport properties of various Hall-type quantum states,including quantum spin Hall(QSH)edge states,quantum valley Hall kink(QVHK)states,and quantum spin-valley Hall kink(QSVHK)states,in the presence of various disorders.Based on the exotic transport features,a spin-valley filter,capable of generating a highly spin-and valley-polarized current,is proposed.The valley index and the spin index of the filtered QSVHK state are determined by the staggered potential and the intrinsic spin-orbit coupling,respectively.The efficiency of the spin-valley filter is supported by the spacial current distribution,the valley-resolved conductance,and the spin-resolved conductance.Compared with a sandwich structure for QSVHK,our proposed spin-valley filter can work with a much smaller size and is more accessible in the experiment.展开更多
The performance of dye-sensitized solar cells (DSSCs) is strongly affected by the properties of semiconductor nanoparticles. In this work, we used TiO2 particles prepared by TiC14 hydrolysis n times on A1203 films ...The performance of dye-sensitized solar cells (DSSCs) is strongly affected by the properties of semiconductor nanoparticles. In this work, we used TiO2 particles prepared by TiC14 hydrolysis n times on A1203 films (A/T(n)), and investigated morphology, photoelectric, and electron transport properties of A/T(n). The TiO2 shell was composed of 10-20 nm nanoparticles and the number of nanoparticles increased with increasing TIC14 treatment times. The highest photoelectric conversion efficiency of 3.23% was obtained as A/T(4). IMPS results indicated that electron transport rate was high enough to conduct current, and was not the dominating effect to limit the Jsc. Jsc was mainly determined by dye loading on TiO2 and the interconnection of TiO2. These may provide a new strategy for preparing semiconductor working electrodes for DSSC.展开更多
Blue and red lights differently regulate leaf photosynthesis. Previous studies indicated that plants under blue light generally exhibit better photosynthetic characteristics than those under red light. However, the re...Blue and red lights differently regulate leaf photosynthesis. Previous studies indicated that plants under blue light generally exhibit better photosynthetic characteristics than those under red light. However, the regulation mechanism of related photosynthesis characteristics remains largely unclear. Here, four light qualities treatments (300 μmol m-2 s-1) including white fluorescent light (FL), blue monochromatic light (B, 440 nm), red monochromatic light (R, 660 nm), and a combination of red and blue light (RB, R:B=8:1) were carried out to investigate their effects on the activity of photosystem II (PSII) and photosystem I (PSI), and photosynthetic electron transport capacity in the leaves of cucumber (Cucumis sativus L.) seedlings. The results showed that compared to the FL treatment, the R treatment significantly limited electron transport rate in PSII (ETR11) and in PSI (ETR1) by 79.4 and 66.3%, respectively, increased non-light induced non-photochemical quenching in PSII (q^No) and limitation of donor side in PSI (φND) and reduced most JIP-test parameters, suggesting that the R treatment induced suboptimal activity of photosystems and inhibited electron transport from PSII donor side up to PSI. However, these suppressions were effectively alleviated by blue light addition (RB). Compared with the R treatment, the RB treatment significantly increased ETR, and ETR1 by 176.9 and 127.0%, respectively, promoted photosystems activity and enhanced linear electron transport by elevating electron transport from QA to PSI. The B treatment plants exhibited normal photosystems activity and photosynthetic electron transport capacity similar to that of the FL treatment. It was concluded that blue light is more essential than red light for normal photosynthesis by mediating photosystems activity and photosynthetic electron transport capacity.展开更多
This paper establishes the energy selective electron (ESE) engine with double resonances as a refrigerator in one dimensional (1D) system. It consists of two infinitely large electron reservoirs with different tem...This paper establishes the energy selective electron (ESE) engine with double resonances as a refrigerator in one dimensional (1D) system. It consists of two infinitely large electron reservoirs with different temperatures and chemical potentials, and they are perfectly thermally insulated from each other and interaction only via a double 'idealized energy filter' whose widths are all finite. Taking advantage of the density of state and Fermi distribution in the 1D system, the heat flux into each reservoir may then be calculated. Moreover, the coefficient of performance may be derived from the expressions for the heat flux into the hot and cold reservoirs. The performance characteristic curves are plotted by numerical analysis. The influences of the resonances widths, the energy position of resonance and the space of two resonances on performance of the ESE refrigerator are discussed. The results obtained here have theoretical significance for the understanding of thermodynamic performance of the micro-nano devices.展开更多
CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas m...CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment.展开更多
The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporou...The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole-Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of inter- facial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.展开更多
Non-local electron transport in laser-produced plasmas under inertial confinement fusion (ICF) conditions is studied based on Fokker-Planck (FP) and hydrodynamic simulations. A comparison between the classical Spi...Non-local electron transport in laser-produced plasmas under inertial confinement fusion (ICF) conditions is studied based on Fokker-Planck (FP) and hydrodynamic simulations. A comparison between the classical Spitzer-Harm (SH) transport model and non-local transport models has been made. The result shows that among those non-local models the Epperlein and Short (ES) model of heat flux is in reasonable agreement with the FP simulation in overdense region. However, the non-local models are invalid in the hot underdense plasmas. Hydrodynamic simulation is performed with the flux limiting model and the non-local model, separately. The simulation results show that in the underdense region of the laser-produced plasmas the temperature given by the flux limiting model is significantly higher than that given with the non-local model.展开更多
We have studied the quantum transport of electrons in a three-step single-barrier A1GaAs heterostructure under electric field. Using the quantum transmitting boundary method and Tsu-Esaki approach, we have calculated ...We have studied the quantum transport of electrons in a three-step single-barrier A1GaAs heterostructure under electric field. Using the quantum transmitting boundary method and Tsu-Esaki approach, we have calculated the transmission coefficient and current-voltage characteristic. The difference of the effective mass among the three barriers is taken into account. Effects of the barrier width on transmission coefficient and peak-to-valley current ratios are examined. The largest peak-to-valley current ratio is obtained when the ratio of widths of the left, middle, and right barrier is fixed at 4:2:1. The calculated results may be helpful for designing devices based on three-step barrier heterostructures.展开更多
Perovskite/silicon tandem solar cells(PSTSCs) have exhibited huge technological potential for breaking the Shockley-Queisser limit of single-junction solar cells. The efficiency of P-I-N type PSTSCs has surpassed the ...Perovskite/silicon tandem solar cells(PSTSCs) have exhibited huge technological potential for breaking the Shockley-Queisser limit of single-junction solar cells. The efficiency of P-I-N type PSTSCs has surpassed the single-junction limit, while the performance of N-I-P type PSTSCs is far below the theoretical value. Here, we developed a composite electron transport layer for N-I-P type monolithic PSTSCs with enhanced open-circuit voltage(VOC) and power conversion efficiency(PCE). Lithium chloride(Li Cl) was added into the tin oxide(SnO_(2)) precursor solution, which simultaneously passivated the defects and increased the electron injection driving force at the electron transfer layer(ETL)/perovskite interface.Eventually, we achieved monolithic PSTSCs with an efficiency of 25.42% and V_(OC) of 1.92 V, which is the highest PCE and VOCin N-I-P type perovskite/Si tandem devices. This work on interface engineering for improving the PCE of monolithic PSTSCs may bring a new hot point about perovskite-based tandem devices.展开更多
The transport of sub-picosecond laser-driven fast electrons in nanopore array targets is studied.Attributed to the generation of micro-structured magnetic fields,most fast electron beams are proven to be effectively g...The transport of sub-picosecond laser-driven fast electrons in nanopore array targets is studied.Attributed to the generation of micro-structured magnetic fields,most fast electron beams are proven to be effectively guided and restricted during the propagation.Different transport patterns of fast electrons in the targets are observed in experiments and reproduced by particle-in-cell simulations,representing two components:initially collimated low-energy electrons in the center and high-energy scattering electrons turning into surrounding annular beams.The critical energy for confined electrons is deduced theoretically.The electron guidance and confinement by the nano-structured targets offer a technological approach to manipulate and optimize the fast electron transport by properly modulating pulse parameters and target design,showing great potential in many applications including ion acceleration,microfocus x-ray sources and inertial confinement fusion.展开更多
At the Earth's magnetopause, the electron transport due to kinetic Alfvén waves(KAWs) is investigated in an ion-scale flux rope by the Magnetospheric Multiscale mission. Clear electron dropout around 90° ...At the Earth's magnetopause, the electron transport due to kinetic Alfvén waves(KAWs) is investigated in an ion-scale flux rope by the Magnetospheric Multiscale mission. Clear electron dropout around 90° pitch angle is observed throughout the flux rope, where intense KAWs are identified. The KAWs can effectively trap electrons by the wave parallel electric field and the magnetic mirror force, allowing electrons to undergo Landau resonance and be transported into more field-aligned directions. The pitch angle range for the trapped electrons is estimated from the wave analysis, which is in good agreement with direct pitch angle measurements of the electron distributions. The newly formed beam-like electron distribution is unstable and excites whistler waves,as revealed in the observations. We suggest that KAWs could be responsible for the plasma depletion inside a flux rope by this transport process, and thus be responsible for the formation of a typical flux rope.展开更多
A PIC (particle-in-cell)-MC (Monte Carlo) code to model electron beam transport into dense matter is developed. The background target is treated as a cold, stationary fluid and the fast electrons as particles with...A PIC (particle-in-cell)-MC (Monte Carlo) code to model electron beam transport into dense matter is developed. The background target is treated as a cold, stationary fluid and the fast electrons as particles with the relativistic motions. The process is described by a particle-in-cell method with consideration of the influence of both the self-generated electric and magnetic fields as well as collisions between the fast electrons and the target. The collisional part of the code is solved by the Monte Carlo-type method. Furthermore by assuming that the background current balances with the fast electron current, the electric field is given by the Ohm's law and the magnetic field is calculated from the Faraday's law. Both are solved in a two-dimensional cylindrical geometry. The algorithms implemented in the code are demonstrated and the numerical experiments are performed for monoenergy homogeneous fast electron beam transport in an aluminum target when the fields, collision and angular scattering are switched on and off independently.展开更多
基金financially supported by the project of the National Natural Science Foundation of China(52202115 and 52172101)the China Postdoctoral Science Foundation(2022M722586)+2 种基金the Natural Science Foundation of Chongqing,China(CSTB2022NSCQ-MSX1085)the Shaanxi Science and Technology Innovation Team(2023-CX-TD-44)the Fundamental Research Funds for the Central Universities(3102019JC005 and G2022KY0604)。
文摘Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.
基金supported by the National Natural Science Foundation of China(61904166,22209145)the Natural Science Foundation of Sichuan Province(2022NSFSC0258)the Fundamental Research Funds for the Central Universities(YJ2021129)。
文摘The unique advantages of one-dimensional(1D)oriented nanostructures in light-trapping and chargetransport make them competitive candidates in photovoltaic(PV)devices.Since the emergence of perovskite solar cells(PSCs),1D nanostructured electron transport materials(ETMs)have drawn tremendous interest.However,the power conversion efficiencies(PCEs)of these devices have always significantly lagged behind their mesoscopic and planar counterparts.High-efficiency PSCs with 1D ETMs showing efficiency over 22%were just realized in the most recent studies.It yet lacks a comprehensive review covering the development of 1D ETMs and their application in PSCs.We hence timely summarize the advances in 1D ETMs-based solar cells,emphasizing on the fundamental and optimization issues of charge separation and collection ability,and their influence on PV performance.After sketching the classification and requirements for high-efficiency 1D nanostructured solar cells,we highlight the applicability of 1D TiO_(2)nanostructures in PSCs,including nanotubes,nanorods,nanocones,and nanopyramids,and carefully analyze how the electrostatic field affects cell performance.Other kinds of oriented nanostructures,e.g.,ZnO and SnO_(2)ETMs,are also described.Finally,we discuss the challenges and propose some potential strategies to further boost device performance.This review provides a broad range of valuable work in this fast-developing field,which we hope will stimulate research enthusiasm to push PSCs to an unprecedented level.
基金supported by the New&Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)granted financial resource from the Ministry of Trade,Industry&Energy(MOTIE),Republic of Korea(No.20213091010020)National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(2020R1A2C1101085)+2 种基金the Korea Institute of Planning and Evaluation for Technology in Food,Agriculture and Forestry(IPET)and Korea Smart Farm R&D Foundation(KosFarm)through Smart Farm Innovation Technology Development Programfunded by the Ministry of Agriculture,Food and Rural Affairs(MAFRA)the Ministry of Science and ICT(MSIT),Rural Development Administration(RDA)(421036-03).
文摘Electron transport layer(ETL)is pivotal to charge carrier transport for PSCs to reach the Shockley-Queisser limit.This study provides a fundamental understanding of heterojunction electron transport layers(ETLs)at the atomic level for stable and efficient perovskite solar cells(PSCs).The bilayer structure of an ETL composed of SnO_(2) on TiO_(2) was examined,revealing a critical factor limiting its potential to obtain efficient performance.Alteration of oxygen vacancies in the TiO_(2) underlayer via an annealing process is found to induce manipulated band offsets at the interface between the TiO_(2) and SnO_(2) layers.In-depth electronic investigations of the bilayer structure elucidate the importance of the electronic properties at the interface between the TiO_(2) and SnO_(2) layers.The apparent correlation in hysteresis phenomena,including current density-voltage(J-V)curves,appears as a function of the type of band alignment.Density functional theory calculations reveal the intimate relationship between oxygen vacancies,deep trap states,and charge transport efficiency at the interface between the TiO_(2) and SnO_(2) layers.The formation of cascade band alignment via control over the TiO_(2) underlayer enhances device performance and suppresses hysteresis.Optimal performance exhibits a power conversion efficiency(PCE)of 23.45%with an open-circuit voltage(V_(oc))of 1.184 V,showing better device stability under maximum power point tracking compared with a staggered bilayer under one-sun continuous illumination.
基金supported by the Solar Energy Research Institute of Singapore(SERIS)at the National University of Singapore(NUS).SERIS is supported by NUS,the National Research Foundation Singapore(NRF),the Energy Market Authority of Singapore(EMA),and the Singapore Economic Development Board(EDB)support from the Science and Engineering Research Council of Singapore with Grant No.A1898b0043Singapore NRF CRP Grant No.NRF-CRP24-2020-0002.
文摘Electron transport layers(ETLs)are crucial for achieving efficient and stable planar perovskite solar cells(PSCs).Reports on versatile inorganic ETLs using a simple film fabrication method and applicability for both low-cost planar regular and inverted PSCs with excellent efficiencies(>22%)and high stability are very limited.Herein,we employ a novel inorganic ZnSe as ETL for both regular and inverted PSCs to improve the efficiency and stability using a simple thermal evaporation method.The TiO_(2)-ZnSe-FAPbl_(3)heterojunction could be formed,resulting in an improved charge collection and a decreased carrier recombination further proved through theoretical calculations.The optimized regular PSCs based on TiO_(2)/ZnSe have achieved 23.25%efficiency with negligible hysteresis.In addition,the ZnSe ETL can also effectively replace the unstable bathocuproine(BCP)in inverted PSCs.Consequently,the ZnSe-based inverted device realizes a champion efficiency of 22.54%.Moreover,the regular device comprising the TiO_(2)/ZnSe layers retains 92%of its initial PCE after 10:00 h under 1 Sun continuous illumination and the inverted device comprising the C_(60)/ZnSe layers maintains over 85%of its initial PCE at 85℃for 10:00 h.This highlights one of the best results among universal ETLs in both regular and inverted perovskite photovoltaics.
基金supported by the National Key R&D Program of China (No. 2016YFA0401100)National Natural Science Foundation of China (Nos. 12175154, 11875092, and 12005149)the Natural Science Foundation of Top Talent of Shenzhen Technology University (Nos. 2019010801001 and 2019020801001)。
文摘Evolution of an electrostatic plasma wave driven by a low-density ultra-relativistic electron beam in dense inhomogeneous plasma is considered. In particular, the wavelength variation as observed at fixed locations in the plasma is analyzed in terms of the wave characteristics. It is shown that for a negative density gradient, the observed local wavelength decreases monotonically with time, but for a positive density gradient, it first increases and then decreases with time, accompanied by reversal of the wave phase. However, in both cases the local wavelength eventually decreases with time since Landau damping becomes significant as the wavelength becomes of the order of the plasma Debye length. Results from particle-in-cell simulations agree well with theoretical analyses of the wavelength variation.
基金supported by the National Key R&D Program of China(2022YFA2105900)the National Natural Science Foundation of China(22178197)。
文摘Highly-efficient oxidation of 5-hydroxymethylfurtural(HMF) to 2,5-furandicarboxylic acid(FDCA) at low temperature with air as the oxidant is still challenging.Herein,inspired by the respirato ry electron transport chain(ETC) of living cells mediated by electron carriers,we constructed artificial ETCs and transformed liquid flow fuel cells(LFFCs) to flexible reactors for efficient oxidation of HMF to produce FDCA under mild conditions.This LFFC reactor employed an electrodeposition modified nickel foam as an anode to promote HMF oxidation and(VO_(2))_(2)SO_(4) as a cathode electron carrier to facilitate the electron transfer to air.The reaction rate could be easily controlled by selecting the anode catalyst,adjusting the external loading and changing the cathodic electron carrier or oxidants.A maximal power density of 44.9 mW cm^(-2) at room temperature was achieved,while for FDCA production,short-circuit condition was preferred to achieve quick transfer of electrons.For a single batch operation with 0.1 M initial HMF,FDCA yield reached 97.1%.By fed-batch operation,FDCA concentration reached 144.5 g L^(-1) with a total yield of 96%.Ni^(2+)/Ni^(3+) redox couple was the active species mediating the electron transfer,while both experimental and DFT calculation results indicated that HMFCA pathway was the preferred reaction mechanism.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12004035)the National Natural Science Fund for Excellent Young Scientists Fund Program(Overseas)。
文摘Valleytronics materials are a kind of special semiconductors which can host multiple symmetry-connected and wellseparated electron or hole pockets in the Brillouin zone when the system is slightly n or p doped. Since the low-energy particles residing in these pockets generally are not easily scattered to each other by small perturbations, they are endowed with an additional valley degree of freedom. Analogous to spin, the valley freedom can be used to process information,leading to the concept of valleytronics. The prerequisite for valleytronics is the generation of valley polarization. Thus,a focus in this field is achieving the electric generation of valley polarization, especially the static generation by the gate electric field alone. In this work, we briefly review the latest progress in this research direction, focusing on the concepts of the couplings between valley and layer, i.e., the valley–layer coupling which permits the gate-field control of the valley polarization, the couplings between valley, layer, and spin in magnetic systems, the physical properties, the novel designing schemes for electronic devices, and the material realizations of the gate-controlled valleytronics materials.
基金supported by the Open Project Program of the State Key Laboratory of Materials-Oriented Chemical Engineering(KL21-05)the support of the Instrumental Analysis Center,Jiangsu University of Science and Technology.
文摘The sluggish redox kinetics of polysulfides in lithium-sulfur(Li-S)batteries are a significant obstacle to their widespread adoption as energy storage devices.However,recent studies have shown that tungsten oxide(WO_(3))can facilitate the conversion kinetics of polysulfides in Li-S batteries.Herein,we fabricated host materials for sulfur using nitrogen-doped carbon nanotubes(N-CNTs)and WO_(3).We used low-cost components and simple procedures to overcome the poor electrical conductivity that is a disadvantage of metal oxides.The composites of WO_(3) and N-CNTs(WO_(3)/N-CNTs)create a stable framework structure,fast ion diffusion channels,and a 3D electron transport network during electrochemical reaction processes.As a result,the WO_(3)/N-CNT-Li2S6 cathode demonstrates high initial capacity(1162 mA·h·g^(-1) at 0.5℃),excellent rate performance(618 mA·h·g^(-1) at 5.5℃),and a low capacity decay rate(0.093%up to 600 cycles at 2℃).This work presents a novel approach for preparing tungsten oxide/carbon composite catalysts that facilitate the redox kinetics of polysulfide conversion.
基金Project supported by the National Natural Science Foundation of China (Grant No.12104012)the Natural Science Foundation of Anhui Province of China (Grant No.2108085MB42)+2 种基金the Key Research and Development Plan of Anhui Province of China (Grant No.202104a05020048)the Major Science and Technology Project of Anhui Province of China (Grant No.2021e03020007)the Doctor Foundation of Anhui Jianzhu University (Grant No.2019QDZ45)。
文摘Bismuthene,an inherently hexagonal structure characterized by a huge bulk gap,offers a versatile platform for investigating the electronic transport of various topological quantum states.Using nonequilibrium Green's function method and Landauer-Büttiker formula,we thoroughly investigate the transport properties of various Hall-type quantum states,including quantum spin Hall(QSH)edge states,quantum valley Hall kink(QVHK)states,and quantum spin-valley Hall kink(QSVHK)states,in the presence of various disorders.Based on the exotic transport features,a spin-valley filter,capable of generating a highly spin-and valley-polarized current,is proposed.The valley index and the spin index of the filtered QSVHK state are determined by the staggered potential and the intrinsic spin-orbit coupling,respectively.The efficiency of the spin-valley filter is supported by the spacial current distribution,the valley-resolved conductance,and the spin-resolved conductance.Compared with a sandwich structure for QSVHK,our proposed spin-valley filter can work with a much smaller size and is more accessible in the experiment.
基金Project supported by the National Materials Genome Project of China(Grant No.2016YFB0700600)the National Natural Science Foundation of China(Grant No.51673204)
文摘The performance of dye-sensitized solar cells (DSSCs) is strongly affected by the properties of semiconductor nanoparticles. In this work, we used TiO2 particles prepared by TiC14 hydrolysis n times on A1203 films (A/T(n)), and investigated morphology, photoelectric, and electron transport properties of A/T(n). The TiO2 shell was composed of 10-20 nm nanoparticles and the number of nanoparticles increased with increasing TIC14 treatment times. The highest photoelectric conversion efficiency of 3.23% was obtained as A/T(4). IMPS results indicated that electron transport rate was high enough to conduct current, and was not the dominating effect to limit the Jsc. Jsc was mainly determined by dye loading on TiO2 and the interconnection of TiO2. These may provide a new strategy for preparing semiconductor working electrodes for DSSC.
基金supported by the Special Fund for Nonprofit Industry (Agriculture) Research Project (201303014)Earmarked Fund for Beijing Fruit Vegetable Innovation Team Project of Modern Agro-industry Technology Research System (GCTDZJ2014033007) in China
文摘Blue and red lights differently regulate leaf photosynthesis. Previous studies indicated that plants under blue light generally exhibit better photosynthetic characteristics than those under red light. However, the regulation mechanism of related photosynthesis characteristics remains largely unclear. Here, four light qualities treatments (300 μmol m-2 s-1) including white fluorescent light (FL), blue monochromatic light (B, 440 nm), red monochromatic light (R, 660 nm), and a combination of red and blue light (RB, R:B=8:1) were carried out to investigate their effects on the activity of photosystem II (PSII) and photosystem I (PSI), and photosynthetic electron transport capacity in the leaves of cucumber (Cucumis sativus L.) seedlings. The results showed that compared to the FL treatment, the R treatment significantly limited electron transport rate in PSII (ETR11) and in PSI (ETR1) by 79.4 and 66.3%, respectively, increased non-light induced non-photochemical quenching in PSII (q^No) and limitation of donor side in PSI (φND) and reduced most JIP-test parameters, suggesting that the R treatment induced suboptimal activity of photosystems and inhibited electron transport from PSII donor side up to PSI. However, these suppressions were effectively alleviated by blue light addition (RB). Compared with the R treatment, the RB treatment significantly increased ETR, and ETR1 by 176.9 and 127.0%, respectively, promoted photosystems activity and enhanced linear electron transport by elevating electron transport from QA to PSI. The B treatment plants exhibited normal photosystems activity and photosynthetic electron transport capacity similar to that of the FL treatment. It was concluded that blue light is more essential than red light for normal photosynthesis by mediating photosystems activity and photosynthetic electron transport capacity.
基金supported by National Natural Science Foundation of China (Grant No 10765004)Science and Technology Foundation of Jiangxi Education Bureau,China
文摘This paper establishes the energy selective electron (ESE) engine with double resonances as a refrigerator in one dimensional (1D) system. It consists of two infinitely large electron reservoirs with different temperatures and chemical potentials, and they are perfectly thermally insulated from each other and interaction only via a double 'idealized energy filter' whose widths are all finite. Taking advantage of the density of state and Fermi distribution in the 1D system, the heat flux into each reservoir may then be calculated. Moreover, the coefficient of performance may be derived from the expressions for the heat flux into the hot and cold reservoirs. The performance characteristic curves are plotted by numerical analysis. The influences of the resonances widths, the energy position of resonance and the space of two resonances on performance of the ESE refrigerator are discussed. The results obtained here have theoretical significance for the understanding of thermodynamic performance of the micro-nano devices.
基金supported by National Natural Science Foundation of China(No.51337006)。
文摘CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61176044 and 11074224)the Science and Technology Project for Innovative Scientist of Henan Province,China(Grant No.1142002510017)the Science and Technology Project on Key Problems of Henan Province,China(Grant No.082101510007)
文摘The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole-Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of inter- facial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10375064, 10575102, 10625523), and the National High Technology Inertial Confinement Fusion Foundation of China.
文摘Non-local electron transport in laser-produced plasmas under inertial confinement fusion (ICF) conditions is studied based on Fokker-Planck (FP) and hydrodynamic simulations. A comparison between the classical Spitzer-Harm (SH) transport model and non-local transport models has been made. The result shows that among those non-local models the Epperlein and Short (ES) model of heat flux is in reasonable agreement with the FP simulation in overdense region. However, the non-local models are invalid in the hot underdense plasmas. Hydrodynamic simulation is performed with the flux limiting model and the non-local model, separately. The simulation results show that in the underdense region of the laser-produced plasmas the temperature given by the flux limiting model is significantly higher than that given with the non-local model.
基金Project supported by the National Fund for Distinguished Young Scholars of China (Grant No 60425415), the Major Program of the National Natural Science Foundation of China (Grant No 10390162), and the Shanghai Municipal Commission of Science and Technology (Grant No 05XD14020).
文摘We have studied the quantum transport of electrons in a three-step single-barrier A1GaAs heterostructure under electric field. Using the quantum transmitting boundary method and Tsu-Esaki approach, we have calculated the transmission coefficient and current-voltage characteristic. The difference of the effective mass among the three barriers is taken into account. Effects of the barrier width on transmission coefficient and peak-to-valley current ratios are examined. The largest peak-to-valley current ratio is obtained when the ratio of widths of the left, middle, and right barrier is fixed at 4:2:1. The calculated results may be helpful for designing devices based on three-step barrier heterostructures.
基金supported by the National Key Research and Development Program of China (Grant No.2018YFB1500103)the National Natural Science Foundation of China (Grant No.61674084)+4 种基金the Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China (Grant No.B16027)the Tianjin Science and Technology Project (Grant No.18ZXJMTG00220)the Fundamental Research Funds for the Central Universities of Nankai University (Grant Nos.63191736,ZB19500204)the Natural Science Foundation of Tianjin (Grant No.20JCQNJC02070)the China Postdoctoral Science Foundation (Grant No.2020T130317)。
文摘Perovskite/silicon tandem solar cells(PSTSCs) have exhibited huge technological potential for breaking the Shockley-Queisser limit of single-junction solar cells. The efficiency of P-I-N type PSTSCs has surpassed the single-junction limit, while the performance of N-I-P type PSTSCs is far below the theoretical value. Here, we developed a composite electron transport layer for N-I-P type monolithic PSTSCs with enhanced open-circuit voltage(VOC) and power conversion efficiency(PCE). Lithium chloride(Li Cl) was added into the tin oxide(SnO_(2)) precursor solution, which simultaneously passivated the defects and increased the electron injection driving force at the electron transfer layer(ETL)/perovskite interface.Eventually, we achieved monolithic PSTSCs with an efficiency of 25.42% and V_(OC) of 1.92 V, which is the highest PCE and VOCin N-I-P type perovskite/Si tandem devices. This work on interface engineering for improving the PCE of monolithic PSTSCs may bring a new hot point about perovskite-based tandem devices.
基金supported by the National Key R&D Program of China(Grant No.2016YFA0401100)the Science and Technology on Plasma Physics Laboratory(Grant Nos.6142A04180201 and JCKYS2020212006)+1 种基金National Natural Science Foundation of China(Grant No.11975214)the Science Challenge Program(Grant Nos.TZ2016005 and TZ2018005)
文摘The transport of sub-picosecond laser-driven fast electrons in nanopore array targets is studied.Attributed to the generation of micro-structured magnetic fields,most fast electron beams are proven to be effectively guided and restricted during the propagation.Different transport patterns of fast electrons in the targets are observed in experiments and reproduced by particle-in-cell simulations,representing two components:initially collimated low-energy electrons in the center and high-energy scattering electrons turning into surrounding annular beams.The critical energy for confined electrons is deduced theoretically.The electron guidance and confinement by the nano-structured targets offer a technological approach to manipulate and optimize the fast electron transport by properly modulating pulse parameters and target design,showing great potential in many applications including ion acceleration,microfocus x-ray sources and inertial confinement fusion.
基金Supported by the National Natural Science Foundation of China under Grant Nos 41474145,41574159,41731070 and 41504114the Frontier Science Foundation of the Chinese Academy of Sciences under Grant No QYZDJ-SSW-JSC028+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA15052500the Specialized Research Fund for State Key Laboratories of China
文摘At the Earth's magnetopause, the electron transport due to kinetic Alfvén waves(KAWs) is investigated in an ion-scale flux rope by the Magnetospheric Multiscale mission. Clear electron dropout around 90° pitch angle is observed throughout the flux rope, where intense KAWs are identified. The KAWs can effectively trap electrons by the wave parallel electric field and the magnetic mirror force, allowing electrons to undergo Landau resonance and be transported into more field-aligned directions. The pitch angle range for the trapped electrons is estimated from the wave analysis, which is in good agreement with direct pitch angle measurements of the electron distributions. The newly formed beam-like electron distribution is unstable and excites whistler waves,as revealed in the observations. We suggest that KAWs could be responsible for the plasma depletion inside a flux rope by this transport process, and thus be responsible for the formation of a typical flux rope.
基金supported by the National High Technology ICF Committee of Chinathe National Natural Science Fund of China(Nos. 10335020, 10375011, 10576007)the Laboratory of Computational Physics (No. 51479050205ZW0905)
文摘A PIC (particle-in-cell)-MC (Monte Carlo) code to model electron beam transport into dense matter is developed. The background target is treated as a cold, stationary fluid and the fast electrons as particles with the relativistic motions. The process is described by a particle-in-cell method with consideration of the influence of both the self-generated electric and magnetic fields as well as collisions between the fast electrons and the target. The collisional part of the code is solved by the Monte Carlo-type method. Furthermore by assuming that the background current balances with the fast electron current, the electric field is given by the Ohm's law and the magnetic field is calculated from the Faraday's law. Both are solved in a two-dimensional cylindrical geometry. The algorithms implemented in the code are demonstrated and the numerical experiments are performed for monoenergy homogeneous fast electron beam transport in an aluminum target when the fields, collision and angular scattering are switched on and off independently.