Optical metasurfaces,which consist of subwavelength scale meta-atoms,represent a novel platform to manipulate the polarization and phase of light.The optical performance of metasurfaces heavily relies on the quality o...Optical metasurfaces,which consist of subwavelength scale meta-atoms,represent a novel platform to manipulate the polarization and phase of light.The optical performance of metasurfaces heavily relies on the quality of nanofabrication.Retrieving the Jones matrix of an imperfect metasurface optical element is highly desirable.We show that this can be realized by decomposing the generalized Jones matrix of a meta-atom into two parallel ones,which correspond to the ideal matrix and a phase retardation.To experimentally verify this concept,we designed and fabricated metasurface polarizers,which consist of geometric phase-controlled dielectric meta-atoms.By scanning the polarization states of the incident and transmitted light,we are able to extract the coefficients of the two parallel matrices of a metasurface polarizer.Based on the results of the Jones matrix decomposition,we also demonstrated polarization image encryption and spin-selective optical holography.The proposed Jones matrix retrieval protocol may have important applications in computational imaging,optical computing,optical communications,and so on.展开更多
In this work, electrochemical plating treatments were applied to ASTM A36 steel specimens to study the efficiency and limitations of this method for arresting fatigue crack propagation. Electroplated iron was deposite...In this work, electrochemical plating treatments were applied to ASTM A36 steel specimens to study the efficiency and limitations of this method for arresting fatigue crack propagation. Electroplated iron was deposited onto the crack surfaces using a circuit in which Swedish Iron served as the anode in a solution of Ammonium Iron(II) Sulfate Hexahydrate. The iron ions were driven into fatigue cracks that were formed within ASTM E399 compact tension specimens. This work showed that an iron-plating treatment operated at 20°C can arrest fatigue crack propagation for a significant period of cycles. The propagation re-initiation lives that resulted ranged from 11,000 to 230,000 cycles. As observed in prior work, the propagation re-initiation life correlated strongly to the magnitude of the stress intensity factor range that was applied during cycling. As this stress intensity increased, the propagation re-initiation life decreased. Repeated treatments on the same crack provided extended service lives by as much as 370,000 cycles or 60% of the entire fatigue life of the component. Future work may show that re-application of the treatment, when conducted prior to crack re-initiation, could further extend the service life indefinitely. The Correia crack closure model was modified to provide an empirical expression for predicting the crack re-initiation life of the treated component. Interestingly, highly effective arrest behavior was still observed for cracks that were loaded to stress intensity factors of only 3 - 6 <img src="Edit_f69af9cd-e908-4aef-8ccb-3b1f36e16d08.png" alt="" />during the treatment but then subjected to 20 <img src="Edit_5ddb9cae-23ad-442d-8e6c-63b5e1d99a0f.png" alt="" /> during cyclic loading. Galvanic corrosion of the plated material exposed to simulated seawater was estimated to be 3 mpy. Future work will examine the use of less active plating alloys and the possibility of applying effective treatments into cracks that are in an unloaded state.展开更多
Summary What is already known about this topic?Acute respiratory infections(ARIs)are a significant contributor to illness and death in children.There has been a notable rise in the occurrence of ARIs and the associate...Summary What is already known about this topic?Acute respiratory infections(ARIs)are a significant contributor to illness and death in children.There has been a notable rise in the occurrence of ARIs and the associated pathogens in China,which has garnered worldwide attention.What is added by this report?This study conducted a retrospective analysis of the clinical characteristics of children with ARIs in Wuhan City from September to November 2023.展开更多
Optical holography is a promising technique to achieve a naked-eye 3D display.However,the narrow viewing angle and chromatic aberration are the two key issues that usually limit the holographic display performance.A r...Optical holography is a promising technique to achieve a naked-eye 3D display.However,the narrow viewing angle and chromatic aberration are the two key issues that usually limit the holographic display performance.A recent work proposes a novel way to circumvent these constraints by introducing a color liquid crystal grating into a timesequenced holography system.展开更多
Organic solar cells(OSCs)have emerged as a promising solution for sustainable energy production,offering advantages such as a low carbon footprint,short energy payback period,and compatibility with eco-solvents.Howeve...Organic solar cells(OSCs)have emerged as a promising solution for sustainable energy production,offering advantages such as a low carbon footprint,short energy payback period,and compatibility with eco-solvents.However,the use of hazardous solvents continues to dominate the best-performing OSCs,mainly because of the challenges of controlling phase separation and domain crystallinity in eco-solvents.In this study,we combined the solvent vapor treatment of CS2 and thermal annealing to precisely control the phase separation and domain crystallinity in PM6:M-Cl and PM6:O-Cl systems processed with the eco-solvent o-xylene.This method resulted in a maximum power conversion efficiency(PCE)of 18.4%,which is among the highest values reported for sustainable binary OSCs.Furthermore,the fabrication techniques were transferred from spin coating in a nitrogen environment to blade printing in ambient air,retaining a PCE of 16.0%,showing its potential for high-throughput and scalable production.In addition,a comparative analysis of OSCs processed with hazardous and green solvents was conducted to reveal the differences in phase aggregation.This work not only underscores the significance of sustainability in OSCs but also lays the groundwork for unlocking the full potential of open-air-printable sustainable OSCs for commercialization.展开更多
Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(PEDOT:PSS) has been explored to fabricate flexible and stretchable conductors. Generally, PEDOT:PSS transparent anodes are prepared by spi...Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(PEDOT:PSS) has been explored to fabricate flexible and stretchable conductors. Generally, PEDOT:PSS transparent anodes are prepared by spin-coating method. In this article, we adopt a method by dropping PEDOT:PSS aqueous solution on the PET plastic substrate to fabricate flexible electrodes. Compared with spin coating, drop-coating is simple and cost-effective with large-area fabrications. Through this method, we fabricated highly transparent conductive electrodes and systematically studied their electrical, optical, morphological and mechanical properties. With dimethyl sulfoxide/methanesulfonic acid(DMSO/MSA) treated PEDOT:PSS electrode,bendable devices based on non-fullerene system displayed an open-circuit voltage of 0.925 V, a fill factor of 70.74%, and a high power conversion efficiency(PCE) of 10.23% under 100 mW cm^(-2) illumination, which retained over 80% of the initial PCE value after 1000 bending cycles. Based on the findings, drop-coated PEDOT:PSS electrodes exhibited high suitability for the development of large-area and high-efficiency printed solar cell modules in the future.展开更多
A novel small-molecule(SM) acceptor DTF-IC is designed and synthesized in this work. The power conversion efficiency(PCE) of ternary OSCs increased up to 12.14% from 10.90% by incorporating 10 wt% of DTF-IC as second ...A novel small-molecule(SM) acceptor DTF-IC is designed and synthesized in this work. The power conversion efficiency(PCE) of ternary OSCs increased up to 12.14% from 10.90% by incorporating 10 wt% of DTF-IC as second acceptors into the binary OSCs consisting of PBDB-T as donor and IT-M as acceptor. This was mainly due to the large increase in short-circuit current(Jsc) from 16.18 to 17.95 mA/cm^2, without any drop in the open-circuit voltage(Voc) and fill factor(FF). The addition of DTF-IC enabled the donor and acceptor to form a distinct complementary absorption profile in the visible-light region, which boosted the photon harvesting in the range of 730–800 nm and consequently increased the Jscof the ternary system by 11%. Moreover, there was an energy transfer between the two SM acceptors, favorable for enhancing charge separation and transfer as well as reducing charge recombination at PBDB-T:IT-M and PBDB-T:DTF-IC interface. Simultaneously, HOMO and LUMO energy levels of DTF-IC were lower than those of PBDB-T, but still higher than those of IT-M. Thus, DTF-IC is able to provide a cascading energy level with the host donor and acceptor which are beneficial for efficient charge transfer between the acceptors and facilitating exciton dissociation and carrier transport. Meanwhile, the highly crystalline DTF-IC as a third component can improve the crystallization process of the active layer while maintaining proper phase separation. This work proposes a novel idea for non-fullerene acceptors achieved via twin spiro-type structure modifying by indanone and provides a new direction for the selection of ternary solar cell materials.展开更多
Transparent electrodes(TEs)with high chemical stability and excellent flexibility are critical for flexible optoelectronic devices,such as photodetectors,solar cells,and light-emitting diodes.Ultrathin metal electrode...Transparent electrodes(TEs)with high chemical stability and excellent flexibility are critical for flexible optoelectronic devices,such as photodetectors,solar cells,and light-emitting diodes.Ultrathin metal electrode(thickness less than 20 nm)has been a promising TE candidate,but the fabrication can only be realized by vacuum-based technologies to date,and require tedious surface engineering of the substrates,which are neither ideal for polymeric based flexible applications nor suitable for roll-to-roll large-scale manufacture.This paper presents high-performance nanostructured transparent metal electrodes formation via displacement-diffusion-etch(DDE)process,which enables the solution-processed sub-20-nm-thick ultrathin gold electrodes(UTAuEs)on a wide variety of hard and soft substrates.UTAuEs fabricated on flexible polyethylene terephthalate(PET)substrates show a high chemical/environmental stability and superior bendability to commercial flexible indiumtin-oxide(ITO)electrodes.Moreover,flexible organic solar cells made with UTAuEs show similar power conversion efficiency but much enhanced flexibility,in comparison to that of ITO-based devices.展开更多
The benchmark tin oxide(SnO_(2))electron transporting layers(ETLs)have enabled remarkable progress in planar perovskite solar cell(PSCs).However,the energy loss is still a challenge due to the lack of“hidden interfac...The benchmark tin oxide(SnO_(2))electron transporting layers(ETLs)have enabled remarkable progress in planar perovskite solar cell(PSCs).However,the energy loss is still a challenge due to the lack of“hidden interface”control.We report a novel ligand-tailored ultrafine SnO_(2) quantum dots(QDs)via a facile rapid room temperature synthesis.Importantly,the ligand-tailored SnO_(2) QDs ETL with multi-functional terminal groups in situ refines the buried interfaces with both the perovskite and transparent electrode via enhanced interface binding and perovskite passivation.These novel ETLs induce synergistic effects of physical and chemical interfacial modulation and preferred perovskite crystallization-directing,delivering reduced interface defects,suppressed non-radiative recombination and elongated charge carrier lifetime.Power conversion efficiency(PCE)of 23.02%(0.04 cm^(2))and 21.6%(0.98 cm^(2),V_(OC) loss:0.336 V)have been achieved for the blade-coated PSCs(1.54 eV E_(g))with our new ETLs,representing a record for SnO_(2) based blade-coated PSCs.Moreover,a substantially enhanced PCE(V_(OC))from 20.4%(1.15 V)to 22.8%(1.24 V,90 mV higher V_(OC),0.04 cm^(2) device)in the blade-coated 1.61 eV PSCs system,via replacing the benchmark commercial colloidal SnO_(2) with our new ETLs.展开更多
基金supported by the National Key Technologies R&D Program of China (Grant No.2022YFA1404301)the Zhangjiang Laboratory,the National Natural Science Foundation of China (Grant Nos.91950114 and 12161141010)+2 种基金the Guangdong Provincial Innovation and Entrepreneurship Project (Grant No.2017ZT07C071)the Guangdong Provincial Key Laboratory Program (Grant No.2021B1212040001)the Natural Science Foundation of Shenzhen Innovation Commission (Grant No.JCYJ20200109140808088).
文摘Optical metasurfaces,which consist of subwavelength scale meta-atoms,represent a novel platform to manipulate the polarization and phase of light.The optical performance of metasurfaces heavily relies on the quality of nanofabrication.Retrieving the Jones matrix of an imperfect metasurface optical element is highly desirable.We show that this can be realized by decomposing the generalized Jones matrix of a meta-atom into two parallel ones,which correspond to the ideal matrix and a phase retardation.To experimentally verify this concept,we designed and fabricated metasurface polarizers,which consist of geometric phase-controlled dielectric meta-atoms.By scanning the polarization states of the incident and transmitted light,we are able to extract the coefficients of the two parallel matrices of a metasurface polarizer.Based on the results of the Jones matrix decomposition,we also demonstrated polarization image encryption and spin-selective optical holography.The proposed Jones matrix retrieval protocol may have important applications in computational imaging,optical computing,optical communications,and so on.
文摘In this work, electrochemical plating treatments were applied to ASTM A36 steel specimens to study the efficiency and limitations of this method for arresting fatigue crack propagation. Electroplated iron was deposited onto the crack surfaces using a circuit in which Swedish Iron served as the anode in a solution of Ammonium Iron(II) Sulfate Hexahydrate. The iron ions were driven into fatigue cracks that were formed within ASTM E399 compact tension specimens. This work showed that an iron-plating treatment operated at 20°C can arrest fatigue crack propagation for a significant period of cycles. The propagation re-initiation lives that resulted ranged from 11,000 to 230,000 cycles. As observed in prior work, the propagation re-initiation life correlated strongly to the magnitude of the stress intensity factor range that was applied during cycling. As this stress intensity increased, the propagation re-initiation life decreased. Repeated treatments on the same crack provided extended service lives by as much as 370,000 cycles or 60% of the entire fatigue life of the component. Future work may show that re-application of the treatment, when conducted prior to crack re-initiation, could further extend the service life indefinitely. The Correia crack closure model was modified to provide an empirical expression for predicting the crack re-initiation life of the treated component. Interestingly, highly effective arrest behavior was still observed for cracks that were loaded to stress intensity factors of only 3 - 6 <img src="Edit_f69af9cd-e908-4aef-8ccb-3b1f36e16d08.png" alt="" />during the treatment but then subjected to 20 <img src="Edit_5ddb9cae-23ad-442d-8e6c-63b5e1d99a0f.png" alt="" /> during cyclic loading. Galvanic corrosion of the plated material exposed to simulated seawater was estimated to be 3 mpy. Future work will examine the use of less active plating alloys and the possibility of applying effective treatments into cracks that are in an unloaded state.
基金Supported by the National Key Research and Development Program of China(2018YFC1603803)the National Natural Science Foundation of China(31970548)+2 种基金the Knowledge Innovation Program of Wuhan Basic Research(2022020801010569)the Health Commission of Hubei Province(WJ 2021M262)the Natural Science Fund of Hubei Province(2021CFA012,2023AFB221).
文摘Summary What is already known about this topic?Acute respiratory infections(ARIs)are a significant contributor to illness and death in children.There has been a notable rise in the occurrence of ARIs and the associated pathogens in China,which has garnered worldwide attention.What is added by this report?This study conducted a retrospective analysis of the clinical characteristics of children with ARIs in Wuhan City from September to November 2023.
基金the National Key Technologies R&D Program of China(2022YFA1404301)the National Natural Science Foundation of China(12161141010).
文摘Optical holography is a promising technique to achieve a naked-eye 3D display.However,the narrow viewing angle and chromatic aberration are the two key issues that usually limit the holographic display performance.A recent work proposes a novel way to circumvent these constraints by introducing a color liquid crystal grating into a timesequenced holography system.
基金Scientific Research Startup Fund for Shenzhen High-Caliber Personnel of Shenzhen Polytechnic,Grant/Award Number:6022310038kNational Natural Science Foundation of China,Grant/Award Number:62004129+7 种基金Shenzhen Science and Technology Innovation Commission,Grant/Award Numbers:JCYJ20200109105003940,20220811205532001Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2023A1515011677Innovation Team Project of Guangdong,Grant/Award Number:2022KCXTD055China Postdoctoral Science Foundation,Grant/Award Number:2022M720156Post-Doctoral Foundation Project of Shenzhen Polytechnic,Grant/Award Number:6022331001KKing Abdullah University of Science and Technology(KAUST),Grant/Award Numbers:ORFSCRG11-2022-5045,OSR-CARF/CCF-3079Research Grants Council of Hong Kong,Grant/Award Numbers:C7018-20G,CRF C5037-18G,15221320Hong Kong Polytechnic University funds,Grant/Award Numbers:Q-CDA5,8-8480。
文摘Organic solar cells(OSCs)have emerged as a promising solution for sustainable energy production,offering advantages such as a low carbon footprint,short energy payback period,and compatibility with eco-solvents.However,the use of hazardous solvents continues to dominate the best-performing OSCs,mainly because of the challenges of controlling phase separation and domain crystallinity in eco-solvents.In this study,we combined the solvent vapor treatment of CS2 and thermal annealing to precisely control the phase separation and domain crystallinity in PM6:M-Cl and PM6:O-Cl systems processed with the eco-solvent o-xylene.This method resulted in a maximum power conversion efficiency(PCE)of 18.4%,which is among the highest values reported for sustainable binary OSCs.Furthermore,the fabrication techniques were transferred from spin coating in a nitrogen environment to blade printing in ambient air,retaining a PCE of 16.0%,showing its potential for high-throughput and scalable production.In addition,a comparative analysis of OSCs processed with hazardous and green solvents was conducted to reveal the differences in phase aggregation.This work not only underscores the significance of sustainability in OSCs but also lays the groundwork for unlocking the full potential of open-air-printable sustainable OSCs for commercialization.
基金supported by the National Key R&D Program of China (2017YFE0106000)the National Natural Science Foundation of China (51773212, 21574144, 21674123, 61705240)+3 种基金Zhejiang Provincial Natural Science Foundation of China (LR16B040002)Ningbo Municipal Science and Technology Innovative Research Team (2015B11002, 2016B10005)CAS Interdisciplinary Innovation Team, CAS Key Project of Frontier Science Research (QYZDBSSW-SYS030)CAS Key Project of International Cooperation (174433KYSB20160065)
文摘Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(PEDOT:PSS) has been explored to fabricate flexible and stretchable conductors. Generally, PEDOT:PSS transparent anodes are prepared by spin-coating method. In this article, we adopt a method by dropping PEDOT:PSS aqueous solution on the PET plastic substrate to fabricate flexible electrodes. Compared with spin coating, drop-coating is simple and cost-effective with large-area fabrications. Through this method, we fabricated highly transparent conductive electrodes and systematically studied their electrical, optical, morphological and mechanical properties. With dimethyl sulfoxide/methanesulfonic acid(DMSO/MSA) treated PEDOT:PSS electrode,bendable devices based on non-fullerene system displayed an open-circuit voltage of 0.925 V, a fill factor of 70.74%, and a high power conversion efficiency(PCE) of 10.23% under 100 mW cm^(-2) illumination, which retained over 80% of the initial PCE value after 1000 bending cycles. Based on the findings, drop-coated PEDOT:PSS electrodes exhibited high suitability for the development of large-area and high-efficiency printed solar cell modules in the future.
基金supported by the Startup Funding of Hebei University of Technology(208011)the National Key R&D Program of China(2017YFE0106000)+3 种基金the National Natural Science Foundation of China(51773212,21574144,and 61705240)Zhejiang Provincial Natural Science Foundation(LR16B040002)Ningbo Municipal Science and Technology Innovative Research Team(2015B11002 and 2016B10005)CAS Interdisciplinary Innovation Team,CAS Key Project of Frontier Science Research(QYZDB-SSW-SYS030),CAS Key Project of International Cooperation(174433KYSB20160065)
文摘A novel small-molecule(SM) acceptor DTF-IC is designed and synthesized in this work. The power conversion efficiency(PCE) of ternary OSCs increased up to 12.14% from 10.90% by incorporating 10 wt% of DTF-IC as second acceptors into the binary OSCs consisting of PBDB-T as donor and IT-M as acceptor. This was mainly due to the large increase in short-circuit current(Jsc) from 16.18 to 17.95 mA/cm^2, without any drop in the open-circuit voltage(Voc) and fill factor(FF). The addition of DTF-IC enabled the donor and acceptor to form a distinct complementary absorption profile in the visible-light region, which boosted the photon harvesting in the range of 730–800 nm and consequently increased the Jscof the ternary system by 11%. Moreover, there was an energy transfer between the two SM acceptors, favorable for enhancing charge separation and transfer as well as reducing charge recombination at PBDB-T:IT-M and PBDB-T:DTF-IC interface. Simultaneously, HOMO and LUMO energy levels of DTF-IC were lower than those of PBDB-T, but still higher than those of IT-M. Thus, DTF-IC is able to provide a cascading energy level with the host donor and acceptor which are beneficial for efficient charge transfer between the acceptors and facilitating exciton dissociation and carrier transport. Meanwhile, the highly crystalline DTF-IC as a third component can improve the crystallization process of the active layer while maintaining proper phase separation. This work proposes a novel idea for non-fullerene acceptors achieved via twin spiro-type structure modifying by indanone and provides a new direction for the selection of ternary solar cell materials.
基金The authors acknowledge the Research Grant Council of Hong Kong (15304919,15218517,C5037-18G)the Hong Kong Polytechnic University (ZVRP,8-8408,1-CDA5)+2 种基金Shenzhen Science and Technology Innovation Commission (JCYJ20200109105003940)the National Natural Science Foundation of China (51961165102)Guangdong-Hong Kong-Macao Joint Laboratory for PhotonicThermal-Electrical Energy Materials and Devices (GDSTC No.2019B121205001).
文摘Transparent electrodes(TEs)with high chemical stability and excellent flexibility are critical for flexible optoelectronic devices,such as photodetectors,solar cells,and light-emitting diodes.Ultrathin metal electrode(thickness less than 20 nm)has been a promising TE candidate,but the fabrication can only be realized by vacuum-based technologies to date,and require tedious surface engineering of the substrates,which are neither ideal for polymeric based flexible applications nor suitable for roll-to-roll large-scale manufacture.This paper presents high-performance nanostructured transparent metal electrodes formation via displacement-diffusion-etch(DDE)process,which enables the solution-processed sub-20-nm-thick ultrathin gold electrodes(UTAuEs)on a wide variety of hard and soft substrates.UTAuEs fabricated on flexible polyethylene terephthalate(PET)substrates show a high chemical/environmental stability and superior bendability to commercial flexible indiumtin-oxide(ITO)electrodes.Moreover,flexible organic solar cells made with UTAuEs show similar power conversion efficiency but much enhanced flexibility,in comparison to that of ITO-based devices.
基金This work was financially supported by the Research Grants Council of Hong Kong(GRF grant nos.15246816,15218517 and CRF grant no.C5037-18G)Shenzhen Technology Innovation Commission(Project no.JCYJ20200109105003940)+6 种基金the funding provided by the Hong Kong Polytechnic University(Project Code:1-CDA5 and Sir Sze-yuen Chung Endowed Professorship Fund(8-8480))S/TEM work was carried out at the Hong Kong Polytechnic University and was supported by the Hong Kong Research Grants Council through the Early Career Scheme(Project no.25301617)the Hong Kong Polytechnic University grant(Project no.1-ZE6G).X.G.and Y.Z.thank Dr.Wei Lu for optimizing the JEOL JEM-2100F microscope.G.L.and K.L.thank the RGC Postdoctoral Fellowship Scheme(PDFS2021-5S04)K.L.thanks Guangdong Basic and Applied Basic Research Foundation(2020A1515110156)H.H.gratefully acknowledge the support from the National Natural Science Foundation of China(62004129)A.N.and C.S.acknowledge the financial support from Nazarbayev University Grant(090118FD5326 and 110119FD4506)the targeted Program BR05236524,and social policy grants.
文摘The benchmark tin oxide(SnO_(2))electron transporting layers(ETLs)have enabled remarkable progress in planar perovskite solar cell(PSCs).However,the energy loss is still a challenge due to the lack of“hidden interface”control.We report a novel ligand-tailored ultrafine SnO_(2) quantum dots(QDs)via a facile rapid room temperature synthesis.Importantly,the ligand-tailored SnO_(2) QDs ETL with multi-functional terminal groups in situ refines the buried interfaces with both the perovskite and transparent electrode via enhanced interface binding and perovskite passivation.These novel ETLs induce synergistic effects of physical and chemical interfacial modulation and preferred perovskite crystallization-directing,delivering reduced interface defects,suppressed non-radiative recombination and elongated charge carrier lifetime.Power conversion efficiency(PCE)of 23.02%(0.04 cm^(2))and 21.6%(0.98 cm^(2),V_(OC) loss:0.336 V)have been achieved for the blade-coated PSCs(1.54 eV E_(g))with our new ETLs,representing a record for SnO_(2) based blade-coated PSCs.Moreover,a substantially enhanced PCE(V_(OC))from 20.4%(1.15 V)to 22.8%(1.24 V,90 mV higher V_(OC),0.04 cm^(2) device)in the blade-coated 1.61 eV PSCs system,via replacing the benchmark commercial colloidal SnO_(2) with our new ETLs.
