A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion e...A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.展开更多
The phenomenon of liquid metal“heartbeat”oscillation presents intriguing applications in microfluidic devices,drug delivery,andminiature robotics.However,achieving high vibrational kinetic energy outputs in these sy...The phenomenon of liquid metal“heartbeat”oscillation presents intriguing applications in microfluidic devices,drug delivery,andminiature robotics.However,achieving high vibrational kinetic energy outputs in these systems remains challenging.In this study,we developed a graphite ring electrode with V-shaped inner wall that enables wide-ranging control over the oscillation performance based on droplet size and the height of the V-shape.The mechanism driving the heartbeat is defined as a dynamic process involving the transformation of the oxide layer.Through electrochemical analysis,we confirmed three distinct states of the heartbeat and introduced a novel model to elucidate the role of the V-shaped structure in initiating and halting the oscillations.A comprehensive series of experiments explored how various factors,such as droplet volume,voltage,tilt angle,and V-shape height,affect heartbeat performance,achieving a significant conversion from surface energy to vibrational kinetic energy as high as 4732 J m^(-2) s^(-1).The increase in energy output is attributed to the synergistic effect of the V-shape height and droplet size on the oscillations.These results not only advance our understanding of liquidmetal droplet manipulation but also pave the way for designing high-speed microfluidic pumping systems.展开更多
A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platfo...A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platform to simulate the transport process of photons and electrons in the detector. The simulation results show that the conversion efficiency could be more than 65%, if the X-ray beam width is less than about 0.2 mm, and a tungsten slab with 0.2 mm thickness and 30 mm length is employed as a radiation conversion medium. Meanwhile the results indicate that this new detector has higher conversion efficiency as well as less volume. Theoretically this new kind of detector could take place of the traditional scintillation detector for HECT.展开更多
<div style="text-align:justify;"> A high-efficiency ridged magnetically insulated transmission line oscillator (RMILO) is proposed and investigated theoretically and numerically in this paper. In the R...<div style="text-align:justify;"> A high-efficiency ridged magnetically insulated transmission line oscillator (RMILO) is proposed and investigated theoretically and numerically in this paper. In the RMILO, ridge-disk vanes are introduced to enhance the power efficiency. Theoretical investigation shows that the ridge-disk can enhance the coupling impedance of the slow-wave structure (SWS), and so enhance the power efficiency. Moreover, the ridge has a weak influence on frequency, so, it influences little on the tunability of the MILO. In simulation, when the applied voltage is increased to 807 kV, the RMILO can get the 3 dB tunable frequency range with 7.6 - 13.9 GHz and the 3 dB tuning bandwidth with 58.6% which has an increase of 27.6% compared with the conventional MILO. So, the tuning performance of the RMILO is more superior. Besides, the RMILO gets the maximum output power of 7.1 GW, the corresponding power efficiency is 22.6% and the frequency is 1.400 GHz. Furthermore, when the applied voltage is increased to 807 kV, high-power microwave with a power of 13.5 GW, frequency of 1.400 GHz, and ef?ciency of 24.5% is generated, which has an increase of 20.2% compared with the conventional MILO. The simulation results con?rm the ones predicted by theoretical analysis. </div>展开更多
In this paper,we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module.In quasi-continuous wave(QCW)running operation,th...In this paper,we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module.In quasi-continuous wave(QCW)running operation,the average output power of the fundamental laser at 1064 nm reaches as high as 20.98 W at a repetition rate of 50 Hz with a maximum single pulse energy of 419.6 mJ,corresponding to a maximum optical conversion efficiency of 38.8%and a slope efficiency of 41%.展开更多
Frequency generation in highly multimode nonlinear optical systems is inherently a complex process,giving rise to an exceedingly convoluted landscape of evolution dynamics.While predicting and controlling the global c...Frequency generation in highly multimode nonlinear optical systems is inherently a complex process,giving rise to an exceedingly convoluted landscape of evolution dynamics.While predicting and controlling the global conversion efficiencies in such nonlinear environments has long been considered impossible,here,we formally address this challenge even in scenarios involving a very large number of spatial modes.By utilizing fundamental notions from optical statistical mechanics,we develop a universal theoretical framework that effectively treats all frequency components as chemical reactants/products,capable of undergoing optical thermodynamic reactions facilitated by a variety of multi-wave mixing effects.These photon-photon reactions are governed by conservation laws that directly determine the optical temperatures and chemical potentials of the ensued chemical equilibria for each frequency species.In this context,we develop a comprehensive stoichiometric model and formally derive an expression that relates the chemical potentials to the optical stoichiometric coefficients,in a manner akin to atomic/molecular chemical reactions.This advancement unlocks new predictive capabilities that can facilitate the optimization of frequency generation in highly multimode photonic arrangements,surpassing the limitations of conventional schemes that rely exclusively on nonlinear optical dynamics.Notably,we identify a universal regime of Rayleigh-Jeans thermalization where an optical reaction at near-zero optical temperatures can promote the complete and entropically irreversible conversion of light to the fundamental mode at a target frequency.Our theoretical results are corroborated by numerical simulations in settings where second-harmonic generation,sum-frequency generation and four-wave mixing processes can manifest.展开更多
We report the first demonstration of high-efficiency ultraviolet(UV)pulse generation in a resonance-free anti-resonant hollow-core fiber(AR-HCF).Using the wet-etching technique,we successfully reduced the cladding-tub...We report the first demonstration of high-efficiency ultraviolet(UV)pulse generation in a resonance-free anti-resonant hollow-core fiber(AR-HCF).Using the wet-etching technique,we successfully reduced the cladding-tube wall thickness of the AR-HCF to 115 nm,thereby eliminating all cladding-induced structural resonances between the near-infrared pump and the deep UV wavelengths.This structural modification fundamentally suppresses competing conversion to other phase-matching points induced by structural resonances and mitigates the pump spectral broadening limitation,achieving a UV conversion efficiency as high as 12%—twice that of previous demonstrations in gas-filled AR-HCFs.This UV conversion efficiency is comparable to that of meter-scale gas-filled capillaries that require pump pulse energy of hundreds of microjoules while also maintaining the AR-HCF's inherent advantages of centimeter-scale compactness and low pump energy at the few microjoule level.展开更多
Radio-photovoltaic cells(RPVCs)are able to offer high reliability and extended operational lifetimes,making them ideal for harsh-environment applications.However,the two-stage energy conversion process inherently limi...Radio-photovoltaic cells(RPVCs)are able to offer high reliability and extended operational lifetimes,making them ideal for harsh-environment applications.However,the two-stage energy conversion process inherently limits energy conversion efficiency(ECE).This study presents a novel RPVC design based on a waveguide light concentration(WLC)scheme,employing multilayer-stacked GAGG:Ce scintillation waveguides alternately loaded with^(90)Sr radioisotope sources.Electron beam irradiation tests revealed highly efficient radioluminescence(RL)emission from the edge surfaces of GAGG:Ce waveguide at electron energies exceeding 60 keV.A RPVC prototype incorporating 1.43 Ci of^(90)Sr achieved a maximum output power(Pmax)of 48.9μW,with an unprecedented ECE of 2.96%—the highest reported value for radioisotope-powered RPVCs to date.Furthermore,a multi-module integrated RPVC prototype demonstrated a Pmax of 3.17 mW,with a short circuit current of 2.23 mA and an open circuit voltage of 2.14 V.Remarkably,the device exhibited only 13.8%RL performance degradation after a 50-year equivalent electron beam irradiation(total fluence:5.625×10^(18)e/cm^(2)),confirming exceptional radiation hardness.These findings demonstrate that the WLC-based RPVCs achieve both high power output and exceptional long-term stability,representing a substantial advancement for facilitating nuclear battery applications.展开更多
Electromagnetic topological chiral edge states mimicking the quantum Hall effect have attracted a great deal of attention due to their unique features of free backscattering and immunity against sharp bends and defect...Electromagnetic topological chiral edge states mimicking the quantum Hall effect have attracted a great deal of attention due to their unique features of free backscattering and immunity against sharp bends and defects.However,the matching techniques between classical waveguides and the topological one-way waveguide deserve more attention for real-world applications.In this paper,a highly efficient conversion structure between a classical rectangular waveguide and a topological one-way waveguide is proposed and demonstrated at the microwave frequency,which efficiently converts classical guided waves to topological one-way edge states.A tapered transition is designed to match both the momentum and impedance of the classical guided waves and the topological one-way edge states.With the conversion structure,the waves generated by a point excitation source can be coupled to the topological one-way waveguide with very high coupling efficiency,which can ensure high transmission of the whole system(i.e.,from the source and the receiver).Simulation and measurement results demonstrate the proposed method.This investigation is beneficial to the applications of topological one-way waveguides and opens up a new avenue for advanced topological and classical integrated functional devices and systems.展开更多
Perovskite tandem solar cells(TSCs)hold substantial promise for surpassing the efficiency limits of single-junction solar cells.Nevertheless,achieving high open-circuit voltage(VOC)in wide-bandgap perovskite devices r...Perovskite tandem solar cells(TSCs)hold substantial promise for surpassing the efficiency limits of single-junction solar cells.Nevertheless,achieving high open-circuit voltage(VOC)in wide-bandgap perovskite devices remains a challenge due to significant VOC-losses.Here,we introduce a heterogeneous interface anchoring strategy aimed at enhancing interfacial properties by incorporating a silane coupling agent between the perovskite and hole transport layers.Trimethoxysilane(TMOS),an amphiphilic molecule,strengthens interfacial adhesion through enhanced chemical interactions,thereby promoting efficient hole extraction.Additionally,the terminal functional groups of TMOS molecules interact with lead ions,modulating the perovskite film crystallization and improving their overall quality.Devices treated with TMOS exhibit a marked reduction in non-radiative recombination,leading to a significant increase in VOC.Notably,3-cyanopropyltrimethoxysilane(CN-TMOS)optimizes the uniformity and interfacial contact of the perovskite film,achieving a VOC of 1.345 V and a power conversion efficiency(PCE)of 19.69%.The corresponding VOC-loss,relative to the bandgap,is reduced to 0.425 V,one of the lowest values reported for wide-bandgap perovskite single-junction solar cells.Extending this strategy to all-perovskite TSCs,we achieve a PCE of 28.45%and exceptional operational stability,retaining over 90%of the initial efficiency after 500 h of continuous operation under 1 sun illumination.展开更多
A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency（PCE）.The internal quantum efficiency,the series resistance,and the thermal resistance were theoretically opt...A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency（PCE）.The internal quantum efficiency,the series resistance,and the thermal resistance were theoretically optimized.The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers.The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs0.9P0.1/InGaAs quantum well.Experimentally,a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink,and a peak PCE of 60% is obtained at 26.3-W continuous wave output power.The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.展开更多
By using two sections of erbium doped fiber and a fiber optical reflector, a novel, highly efficient L-band amplifier is demonstrated with significantly power-conversion-efficiency enhancement and the gain increasing ...By using two sections of erbium doped fiber and a fiber optical reflector, a novel, highly efficient L-band amplifier is demonstrated with significantly power-conversion-efficiency enhancement and the gain increasing of as much as 13 dB.展开更多
An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ...An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ of 473 nm blue laser pulse energy was achieved by cascade frequency doubling. The second harmonic conversion efficiency was 64.5%, and overall optical-optical efficiency was 4.2%, respectively. The blue laser pulse width was less than 10 ns, and beam quality factor was less than 2.4.展开更多
Frequency tunability has become a subject of concern in the field of high-power microwave（HPM） source research.However, little information about the corresponding mode converter is available. A tunable circularly-po...Frequency tunability has become a subject of concern in the field of high-power microwave（HPM） source research.However, little information about the corresponding mode converter is available. A tunable circularly-polarized turnstilejunction mode converter（TCTMC） for high-power microwave applications is presented in this paper. The input coaxial TEM mode is transformed into TE（10） mode with different phase delays in four rectangular waveguides and then converted into a circularly-polarized TE（11） circular waveguide mode. Besides, the rods are added to reduce or even eliminate the reflection. The innovations in this study are as follows. The tunning mechanism is added to the mode converter, which can change the effective length of rectangular waveguide and the distance between the rods installed upstream and the closest edge of the rectangular waveguide, thus improving the conversion efficiency and bandwidth. The conversion efficiency of TCTMC can reach above 98% over the frequency range of 1.42 GHz–2.29 GHz, and the frequency tunning bandwidth is about 47%. Significantly, TCTMC can obtain continuous high conversion efficiency of different frequency points with the change of tuning mechanism.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11335003
文摘A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.
基金National Natural Science Foundation of China,Grant/Award Number:51901009。
文摘The phenomenon of liquid metal“heartbeat”oscillation presents intriguing applications in microfluidic devices,drug delivery,andminiature robotics.However,achieving high vibrational kinetic energy outputs in these systems remains challenging.In this study,we developed a graphite ring electrode with V-shaped inner wall that enables wide-ranging control over the oscillation performance based on droplet size and the height of the V-shape.The mechanism driving the heartbeat is defined as a dynamic process involving the transformation of the oxide layer.Through electrochemical analysis,we confirmed three distinct states of the heartbeat and introduced a novel model to elucidate the role of the V-shaped structure in initiating and halting the oscillations.A comprehensive series of experiments explored how various factors,such as droplet volume,voltage,tilt angle,and V-shape height,affect heartbeat performance,achieving a significant conversion from surface energy to vibrational kinetic energy as high as 4732 J m^(-2) s^(-1).The increase in energy output is attributed to the synergistic effect of the V-shape height and droplet size on the oscillations.These results not only advance our understanding of liquidmetal droplet manipulation but also pave the way for designing high-speed microfluidic pumping systems.
基金supported by the National Natural Science Foundation of China (No.60672098)the Tackling Key Problems of Science and Technology of ChongQing (No.CSTC2009AC3047)
文摘A new type of solid-conversion gas detector is investigated for high energy X-ray industrial computed tomography (HECT). The conversion efficiency is calculated by using the EGSnrc Monte Carlo code on the Linux platform to simulate the transport process of photons and electrons in the detector. The simulation results show that the conversion efficiency could be more than 65%, if the X-ray beam width is less than about 0.2 mm, and a tungsten slab with 0.2 mm thickness and 30 mm length is employed as a radiation conversion medium. Meanwhile the results indicate that this new detector has higher conversion efficiency as well as less volume. Theoretically this new kind of detector could take place of the traditional scintillation detector for HECT.
文摘<div style="text-align:justify;"> A high-efficiency ridged magnetically insulated transmission line oscillator (RMILO) is proposed and investigated theoretically and numerically in this paper. In the RMILO, ridge-disk vanes are introduced to enhance the power efficiency. Theoretical investigation shows that the ridge-disk can enhance the coupling impedance of the slow-wave structure (SWS), and so enhance the power efficiency. Moreover, the ridge has a weak influence on frequency, so, it influences little on the tunability of the MILO. In simulation, when the applied voltage is increased to 807 kV, the RMILO can get the 3 dB tunable frequency range with 7.6 - 13.9 GHz and the 3 dB tuning bandwidth with 58.6% which has an increase of 27.6% compared with the conventional MILO. So, the tuning performance of the RMILO is more superior. Besides, the RMILO gets the maximum output power of 7.1 GW, the corresponding power efficiency is 22.6% and the frequency is 1.400 GHz. Furthermore, when the applied voltage is increased to 807 kV, high-power microwave with a power of 13.5 GW, frequency of 1.400 GHz, and ef?ciency of 24.5% is generated, which has an increase of 20.2% compared with the conventional MILO. The simulation results con?rm the ones predicted by theoretical analysis. </div>
基金supported by the Nanjing University of Posts and Telecommunications Foundation,China(Grant Nos.JUH219002 and JUH219007)the Key R&D Program of Shandong Province,China(Grant No.2021CXGC010202)。
文摘In this paper,we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module.In quasi-continuous wave(QCW)running operation,the average output power of the fundamental laser at 1064 nm reaches as high as 20.98 W at a repetition rate of 50 Hz with a maximum single pulse energy of 419.6 mJ,corresponding to a maximum optical conversion efficiency of 38.8%and a slope efficiency of 41%.
基金supported by the Air Force Offce of Scientific Research(AFOSR)Multidisciplinary University Research Initiative(MURI)award on Novel light-matter interactions in topologically non-trivial Weyl semimetal structures and systems(award No.FA9550-20-1-0322)AFOSR MURI award on Programmable systems with non-Hermitian quantum dynamics(award no.FA9550-21-1-0202)+5 种基金ONR MURI award on the classical entanglement of light(award No.N00014-20-1-2789)the Army Research Offce(W911NF-23-1-0312)the Department of Energy(DE-SCo022282)W.M.Keck Foundation,the Department of Energy(DE-SCo025224),MPS Simons collaboration(Simons grant No.733682)US Air Force Research Laboratory(FA86511820019)AFRL-Applied Research Solutions(S03015)(FA8650-19-C-1692).
文摘Frequency generation in highly multimode nonlinear optical systems is inherently a complex process,giving rise to an exceedingly convoluted landscape of evolution dynamics.While predicting and controlling the global conversion efficiencies in such nonlinear environments has long been considered impossible,here,we formally address this challenge even in scenarios involving a very large number of spatial modes.By utilizing fundamental notions from optical statistical mechanics,we develop a universal theoretical framework that effectively treats all frequency components as chemical reactants/products,capable of undergoing optical thermodynamic reactions facilitated by a variety of multi-wave mixing effects.These photon-photon reactions are governed by conservation laws that directly determine the optical temperatures and chemical potentials of the ensued chemical equilibria for each frequency species.In this context,we develop a comprehensive stoichiometric model and formally derive an expression that relates the chemical potentials to the optical stoichiometric coefficients,in a manner akin to atomic/molecular chemical reactions.This advancement unlocks new predictive capabilities that can facilitate the optimization of frequency generation in highly multimode photonic arrangements,surpassing the limitations of conventional schemes that rely exclusively on nonlinear optical dynamics.Notably,we identify a universal regime of Rayleigh-Jeans thermalization where an optical reaction at near-zero optical temperatures can promote the complete and entropically irreversible conversion of light to the fundamental mode at a target frequency.Our theoretical results are corroborated by numerical simulations in settings where second-harmonic generation,sum-frequency generation and four-wave mixing processes can manifest.
基金Agency for Science,Technology and Research(M22K2c0089)。
文摘We report the first demonstration of high-efficiency ultraviolet(UV)pulse generation in a resonance-free anti-resonant hollow-core fiber(AR-HCF).Using the wet-etching technique,we successfully reduced the cladding-tube wall thickness of the AR-HCF to 115 nm,thereby eliminating all cladding-induced structural resonances between the near-infrared pump and the deep UV wavelengths.This structural modification fundamentally suppresses competing conversion to other phase-matching points induced by structural resonances and mitigates the pump spectral broadening limitation,achieving a UV conversion efficiency as high as 12%—twice that of previous demonstrations in gas-filled AR-HCFs.This UV conversion efficiency is comparable to that of meter-scale gas-filled capillaries that require pump pulse energy of hundreds of microjoules while also maintaining the AR-HCF's inherent advantages of centimeter-scale compactness and low pump energy at the few microjoule level.
基金supported by the National Key Research and Development Program of China(No.2022YFB1903200)the Electronic Components Project of China(No.2009ZYHN0003).
文摘Radio-photovoltaic cells(RPVCs)are able to offer high reliability and extended operational lifetimes,making them ideal for harsh-environment applications.However,the two-stage energy conversion process inherently limits energy conversion efficiency(ECE).This study presents a novel RPVC design based on a waveguide light concentration(WLC)scheme,employing multilayer-stacked GAGG:Ce scintillation waveguides alternately loaded with^(90)Sr radioisotope sources.Electron beam irradiation tests revealed highly efficient radioluminescence(RL)emission from the edge surfaces of GAGG:Ce waveguide at electron energies exceeding 60 keV.A RPVC prototype incorporating 1.43 Ci of^(90)Sr achieved a maximum output power(Pmax)of 48.9μW,with an unprecedented ECE of 2.96%—the highest reported value for radioisotope-powered RPVCs to date.Furthermore,a multi-module integrated RPVC prototype demonstrated a Pmax of 3.17 mW,with a short circuit current of 2.23 mA and an open circuit voltage of 2.14 V.Remarkably,the device exhibited only 13.8%RL performance degradation after a 50-year equivalent electron beam irradiation(total fluence:5.625×10^(18)e/cm^(2)),confirming exceptional radiation hardness.These findings demonstrate that the WLC-based RPVCs achieve both high power output and exceptional long-term stability,representing a substantial advancement for facilitating nuclear battery applications.
基金supported by the National Natural Science Foundation of China(No.62171082)the Natural Science Foundation of Sichuan Province(No.2022NSFSC0483)。
文摘Electromagnetic topological chiral edge states mimicking the quantum Hall effect have attracted a great deal of attention due to their unique features of free backscattering and immunity against sharp bends and defects.However,the matching techniques between classical waveguides and the topological one-way waveguide deserve more attention for real-world applications.In this paper,a highly efficient conversion structure between a classical rectangular waveguide and a topological one-way waveguide is proposed and demonstrated at the microwave frequency,which efficiently converts classical guided waves to topological one-way edge states.A tapered transition is designed to match both the momentum and impedance of the classical guided waves and the topological one-way edge states.With the conversion structure,the waves generated by a point excitation source can be coupled to the topological one-way waveguide with very high coupling efficiency,which can ensure high transmission of the whole system(i.e.,from the source and the receiver).Simulation and measurement results demonstrate the proposed method.This investigation is beneficial to the applications of topological one-way waveguides and opens up a new avenue for advanced topological and classical integrated functional devices and systems.
基金supported by the National Key R&D Program of China(2023YFE0111500)the National Natural Science Foundation of China(52321006,T2394480,T2394484,22109143,22475196,and 22479131)+9 种基金the Joint Fund for Provincial Science and Technology R&D Program of Henan(242301420051)the Opening Project of the State Key Laboratory of Advanced Technology for Float Glass(2022KF04)the China Postdoctoral Innovative Talent Support Program(BX2021271)the China Postdoctoral Science Foundation(2022M712851)the Graduate Education Reform Project of Henan Province(2023SJGLX136Y)the Key R&D Special Program of Henan Province(241111242000)the Program for Science&Technology Innovation Talents in Universities of Henan Province(25HASTIT005)the Henan Provincial Excellent Youth Science Foundation(252300421172)the Training Plan for Young Backbone Teachers of Zhengzhou University(2023zDGGJS017)and the Joint Research Project of Puyang Shengtong Juyuan New Materials Co.,Ltd.(20230128A).
文摘Perovskite tandem solar cells(TSCs)hold substantial promise for surpassing the efficiency limits of single-junction solar cells.Nevertheless,achieving high open-circuit voltage(VOC)in wide-bandgap perovskite devices remains a challenge due to significant VOC-losses.Here,we introduce a heterogeneous interface anchoring strategy aimed at enhancing interfacial properties by incorporating a silane coupling agent between the perovskite and hole transport layers.Trimethoxysilane(TMOS),an amphiphilic molecule,strengthens interfacial adhesion through enhanced chemical interactions,thereby promoting efficient hole extraction.Additionally,the terminal functional groups of TMOS molecules interact with lead ions,modulating the perovskite film crystallization and improving their overall quality.Devices treated with TMOS exhibit a marked reduction in non-radiative recombination,leading to a significant increase in VOC.Notably,3-cyanopropyltrimethoxysilane(CN-TMOS)optimizes the uniformity and interfacial contact of the perovskite film,achieving a VOC of 1.345 V and a power conversion efficiency(PCE)of 19.69%.The corresponding VOC-loss,relative to the bandgap,is reduced to 0.425 V,one of the lowest values reported for wide-bandgap perovskite single-junction solar cells.Extending this strategy to all-perovskite TSCs,we achieve a PCE of 28.45%and exceptional operational stability,retaining over 90%of the initial efficiency after 500 h of continuous operation under 1 sun illumination.
文摘A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency（PCE）.The internal quantum efficiency,the series resistance,and the thermal resistance were theoretically optimized.The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers.The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs0.9P0.1/InGaAs quantum well.Experimentally,a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink,and a peak PCE of 60% is obtained at 26.3-W continuous wave output power.The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.
文摘By using two sections of erbium doped fiber and a fiber optical reflector, a novel, highly efficient L-band amplifier is demonstrated with significantly power-conversion-efficiency enhancement and the gain increasing of as much as 13 dB.
基金supported by the National Key Research and Development Program of China(No.2016YFC1400902)
文摘An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ of 473 nm blue laser pulse energy was achieved by cascade frequency doubling. The second harmonic conversion efficiency was 64.5%, and overall optical-optical efficiency was 4.2%, respectively. The blue laser pulse width was less than 10 ns, and beam quality factor was less than 2.4.
基金supported by the National Natural Science Foundation of China(Grant No.61671457)
文摘Frequency tunability has become a subject of concern in the field of high-power microwave（HPM） source research.However, little information about the corresponding mode converter is available. A tunable circularly-polarized turnstilejunction mode converter（TCTMC） for high-power microwave applications is presented in this paper. The input coaxial TEM mode is transformed into TE（10） mode with different phase delays in four rectangular waveguides and then converted into a circularly-polarized TE（11） circular waveguide mode. Besides, the rods are added to reduce or even eliminate the reflection. The innovations in this study are as follows. The tunning mechanism is added to the mode converter, which can change the effective length of rectangular waveguide and the distance between the rods installed upstream and the closest edge of the rectangular waveguide, thus improving the conversion efficiency and bandwidth. The conversion efficiency of TCTMC can reach above 98% over the frequency range of 1.42 GHz–2.29 GHz, and the frequency tunning bandwidth is about 47%. Significantly, TCTMC can obtain continuous high conversion efficiency of different frequency points with the change of tuning mechanism.
