Jingwei Intelligent Textile Machinery Co.,Ltd.is a globally leading enterprise in the R&D and manufacturing of textile machinery,affiliated with China National Machinery Industry Group(SINOMACH).As the first moder...Jingwei Intelligent Textile Machinery Co.,Ltd.is a globally leading enterprise in the R&D and manufacturing of textile machinery,affiliated with China National Machinery Industry Group(SINOMACH).As the first modern textile machinery manufacturing base in New China,the company has developed over 70 years to establish a full lifecycle service capability of"machines+components+services+modifications."Its core products,such as Ring Spinning Frames and Combers,feature internationally advanced technologies.With products exported to over 40 countries and regions,the company is committed to providing global customers with intelligent,green textile equipment and full-process solutions.展开更多
Electroluminescent devices based on organic semiconductors have attracted significant attention owing to their promising applications in flat-panel displays.The conventional display pixel consisting of side-by-side ar...Electroluminescent devices based on organic semiconductors have attracted significant attention owing to their promising applications in flat-panel displays.The conventional display pixel consisting of side-by-side arrayed red,green and blue subpixels represents the mature technology but bears an intrinsic deficiency of a low pixel density.Constructing an individual color-tunable pixel that comprises vertically stacked subpixels is considered an advanced technology.Although color-tunable organic light-emitting diodes(OLEDs)have been fabricated using the vacuum deposition of small molecules,the solution processing of conjugated polymers would enable a much simpler and inexpensive manufacturing process.Here we present the all-solution processing of color-tunable OLEDs comprising two vertically stacked polymer emitters.A thin layer of highly conducting and transparent silver nanowires is introduced as the intermediate charge injection contact,which allows the emission spectrum and intensity of the tandem devices to be seamlessly manipulated.To demonstrate a viable application of this technology,a 4-by-4 pixelated matrix color-tunable display was fabricated.展开更多
Field-effect transistors（FETs） of three diketopyrrolopyrroles（DPP）-based small molecules, 3,6-bis（5-phenylthiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolopyrrole-1,4-dione（PDPPP）, 3,6-bis（5-（4-fluorophenyl）th...Field-effect transistors（FETs） of three diketopyrrolopyrroles（DPP）-based small molecules, 3,6-bis（5-phenylthiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolopyrrole-1,4-dione（PDPPP）, 3,6-bis（5-（4-fluorophenyl）thiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolo pyrrole-1,4-dione（FPDPPPF） and 3,6-bis（5-（4-n-butylphenyl）thiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolo pyrrole-1,4-dione（Bu PDPPPBu）, have been studied in this work. Well aligned crystals of the three molecules were grown from para-xylene by droplet-pinned crystallization method. FETs based on these aligned crystals exhibit a hole mobility up to0.19 cm^2 V 1s 1and electron mobility up to 0.008 cm^2 V 1s 1. The achieved hole mobility is of the same order of magnitude as reported highest hole mobility for DPP-based small molecules, but it is much lower than that of the high-performance DPP-based polymers. The relative low mobility is mainly attributed to the rough crystal surfaces with steps and, thus, non-smooth charge transport channels at the interfaces between the crystals and the dielectrics. This work has implications for understanding the low charge mobility of DPP-based small molecules.展开更多
Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through soluti...Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.展开更多
Perovskite solar cells(PSCs) have revolutionized photovoltaic research. As a result, a certified power conversion efficiency(PCE) of 25.5% was recorded in late 2020. Although this efficiency is comparable with silicon...Perovskite solar cells(PSCs) have revolutionized photovoltaic research. As a result, a certified power conversion efficiency(PCE) of 25.5% was recorded in late 2020. Although this efficiency is comparable with silicon solar cells;some issues remain partially unsolved, such as lead toxicity, instability of perovskite materials under continuous illumination, moisture and oxygen, and degradation of the metallic counter electrodes. As an alternative to tackle this last concern, carbon materials have been recently used, due to their good electrical and thermal conductivity, and chemical stability, which makes them one of the most promising materials to replace metallic counter electrodes in the fabrication of PSCs. This review highlights the recent advances of carbon-based PSCs, where the carbon electrode(CE) is the main actor.CEs have become very promising candidates for PSCs;they are mainly fabricated using a simple combination of graphite and carbon black powders embedded in a binder matrix, giving a paste that is then solution-processable, resulting in devices with improved quality stability, when compared to metallic electrodes. In this review, CE’s composition is emphasized, since it can give both, high and lowtemperature processed electrodes, compatible with different device configurations. Finally, the tendencies and opportunities to use CE in PSCs devices are presented.展开更多
To investigate groundwater flow and solute transport characteristics of the karst trough zone in China,tracer experiments were conducted at two adjacent typical karst groundwater flow systems(Yuquandong(YQD)and Migong...To investigate groundwater flow and solute transport characteristics of the karst trough zone in China,tracer experiments were conducted at two adjacent typical karst groundwater flow systems(Yuquandong(YQD)and Migongquan(MGQ))in Sixi valley,western Hubei,China.Highresolution continuous monitoring was utilized to obtain breakthrough curves(BTCs),which were then analyzed using the multi-dispersion model(MDM)and the two-region nonequilibrium model(2RNE)with basic parameters calculated by CXTFIT and QTRACER2.Results showed that:(1)YQD flow system had a complex infiltration matrix with overland flow,conduit flow and fracture flow,while the MGQ flow system was dominated by conduit flow with fast flow transport velocity,but also small amount of fracture flow there;(2)They were well fitted based on the MDM(R^2=0.928)and 2RNE(R^2=0.947)models,indicating that they had strong adaptability in the karst trough zone;(3)conceptual models for YQD and MGQ groundwater systems were generalized.In YQD system,the solute was transported via overland flow during intense rainfall,while some infiltrated down into fissures and conduits.In MGQ system,most were directly transported to spring outlet in the fissureconduit network.展开更多
It is confirmed that phase homogenization is very important for improving the magnetic properties of 2:17-type Sm-Co sintered magnets,In this work,the influence of solid solution process on microstructure and magnetic...It is confirmed that phase homogenization is very important for improving the magnetic properties of 2:17-type Sm-Co sintered magnets,In this work,the influence of solid solution process on microstructure and magnetic properties of the Sm(CobalFe0.233Cu0.073Zr0.024)7.6 sintered magnets was systematically studied.With the solid-solution treating duration(tS)increasing from 0 to 4 h,intrinsic coercivity(Hcj)increases from 12.83 to 36.54 kOe,magnetic field at knee-point(Hknee)increases from2.76 to 19.14 kOe,and the maximum energy product increases from 19.79 to 29.48 MGOe.The electron probe microanalyzer results reveal that there mainly exist gray and dark regions besides"white"rare earth-rich phase,and the conte nt of Sm,Fe and Cu elements for the two kinds of regions changes a lot for the specimens,Furthermore,with tS increasing up to 4 h,the elements content deviation between the gray and dark regions becomes small gradually from 3.94 at%to 0.27 at%,7.66 at%to 0.21 at%and 7.27 at%to 0.16 at%for Sm,Fe and Cu elements,respectively.Moreover,transmission electron microscopy results show that the distribution of cell size is much more concentrated for aged specimens when tS is 4 h.It is also found that the Cu concentration at cell boundaries for the 4 h solid-solution treatment case shows relatively higher values and greater concentration gradient(1.94 at%/nm).It is verified that sufficient solution treatment duration is prerequisite to form these homogeneous microstructural features,which are the key points for obtaining both high Hcj and Hknee.展开更多
Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promis...Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.展开更多
Thermally activated delayed fluorescent(TADF) materials capable of efficient solution-processed nondoped organic light-emitting diodes(OLEDs) are of important and practical significance for further development of OLED...Thermally activated delayed fluorescent(TADF) materials capable of efficient solution-processed nondoped organic light-emitting diodes(OLEDs) are of important and practical significance for further development of OLEDs. In this work, a new electron-donating segment, 2,7-di(9 H-carbazol-9-yl)-9,9-dimethyl-9,10-dihydroacridine(2 Cz-DMAC), was designed to develop solution-processable non-doped TADF emitters. 2 Cz-DMAC can not only simultaneously increase the solubility of compounds and suppress harmful aggregation-caused quenching, but also efficiently broaden the delocalization of the highest occupied molecular orbital and promote the reverse intersystem crossing process. Three new TADF emitters, 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)dibenzo[b,d]thiophene 5,5-dioxide(2 Cz-DMAC-BTB), 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)-9 H-thioxanthen-9-one(2 Cz-DMAC-TXO), 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)thianthrene 5,5,10,10-tetraoxide(2 Cz-DMAC-TTR), were developed by using 2 Cz-DMAC segment as the electron-donor. As anticipated, the solution-processed non-doped OLEDs employing 2 Cz-DMAC-BTB, 2 Cz-DMAC-TXO and 2 CzDMAC-TTR as the emitters respectively exhibited green, orange and red emissions with maximum external quantum efficiencies of 14.0%, 6.6% and 2.9%. These results successfully demonstrate the feasibility and convenience of developing efficient solution-processable non-doped TADF emitters based on 2 CzDMAC segment.展开更多
A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoi...A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoided. The photo-cross-linker, BBP-4, was added into host polymers by simple solution blending process, which was capable of abstracting hydrogen atoms from polymers containing active C--H groups upon exposure to ultraviolet （UV） radiation. The cross-linking can be completed with a relatively long wavelength UV light （365 nm）. The approach has been applied to methacrylate and styrenic polymers such as commercial poly（methylmethacrylate） （PMMA）, poly（iso-butylmethacrylate） （PiBMA） and poly（4-methylstyrene） （PMS）. The cross-linked networks enhanced dielectric properties and solvent resistance of the thin films. The bottom-gate organic field-effect transistors （OFETs） through all solution processes on plastic substrate were fabricated. The OFET devices showed low voltage operation and steep subthreshold swing at relatively small gate dielectric capacitance.展开更多
All-inorganic cesium lead halide perovskites （CsPbX3, X=CF, Br-, I-） could provide comparableoptoelectronic properties as a promising class of materials for photovoltaic cell （PV）, photodetector andlight-emitting ...All-inorganic cesium lead halide perovskites （CsPbX3, X=CF, Br-, I-） could provide comparableoptoelectronic properties as a promising class of materials for photovoltaic cell （PV）, photodetector andlight-emitting diode （LED） with enhanced thermal and moisture stabilities compared to organic-inorganic lead halide species. However, fabrication of CsPbI3 perovskite via facile solution process hasbeen difficult due to instability of CsPbl3 in the perovskite cubic phase in ambient air. Herein, we reportthe synthesis of CsPbl3 perovskite microcrystals by low-temperature, catalyst-free, solution-phasemethod. By applying the time-resolve spectroscopic technique, we determine the carrier diffusioncoefficient of 0.6-1.2 cm2/s, the intrinsic carrier lifetimes of 200-1300 ns and diffusion length of4-10 μm in different individual CsPbl3 perovskite microcrystals. Our results suggest the CsPbl3 perovskitemicrocrystals synthesized by solution process exhibit high quality feature and are suitable forapplications in optoelectronic devices.展开更多
The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have ...The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have been proved to be troublesome and less intuitive. Analytical solutions based on loss-less tube model and average friction tube model are found respectively by using fluid net theory, and they fit the experimental results well. The research work shows that： Fluid net theory can be used to solve the analytical solution of filling and exhausting processes of pneumatic system, and the result of loss-less tube model is close to that of average friction model, so loss-less tube model is recommended since it is simpler, and the difference between filling time and exhausting time is determined by initial and final pressures, the volume of container and the section area of tube, and has nothing to do with the length of the tube.展开更多
Three carbazole-based multiple resonance dendrimers namely D1-BNN,D2-BNN and D3-BNN,are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs)by introducing the first-,second-,and third-...Three carbazole-based multiple resonance dendrimers namely D1-BNN,D2-BNN and D3-BNN,are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs)by introducing the first-,second-,and third-generation carbazole dendrons in periphery of boron,nitrogen-doped polycyclic aromatic hydrocarbon skeleton.Different from D1-BNN containing first-generation carbazole dendron showing moderate photoluminescent quantum efficiency(PLQY)of 68%in solid state and broadened emission bands with full-width at half maximum(FWHM)increasing from 26 nm to 34 nm upon doping concentration growing from 10 wt%to 40 wt%,D3-BNN with the third-generation carbazole dendron exhibits high PLQY of 92%and weak dependence of photoluminescent spectra on doping concentration,which can remain narrowband emissions with unchanged FWHM of 24 nm at same doping concentration range.Solution-processed OLEDs employing D3-BNN as emitter reveal blue electroluminescence at 477 nm with FWHM of 24 nm,and maximum external quantum efficiency(EQE)of 17.3%which is kept at 14.4%at doping concentration of 40 wt%,much superior than the D1-BNN devices showing maximum EQE of 13.0%that drops to 3.7%at 40 wt%doping concentration.展开更多
In this paper, co-doping method is used to improve the current efficiency of solution-processed organic light-emitting diodes(OLEDs). By changing the ratio of two thermally activated delayed fluorescent(TADF) emitters...In this paper, co-doping method is used to improve the current efficiency of solution-processed organic light-emitting diodes(OLEDs). By changing the ratio of two thermally activated delayed fluorescent(TADF) emitters, we studied the performance of device and its mechanism. A solution processed OLED with a structure of indium tin oxide(ITO, 150 nm)/PEDOT:PSS(30 nm)/CBP:4 Cz IPN-x%:4 Cz PN-y%(30 nm)/TPBi(40 nm)/Li F(1 nm)/Al(100 nm) was fabricated. The current efficiencies of 26.6 cd/A and 26.4 cd/A were achieved by the devices with dopant ratio of 6% 4 Cz IPN:2% 4 Cz PN and 2% 4 Cz IPN:6% 4 Cz PN in emitting material layer(EML), respectively. By investigating the tendency of current density change in devices with different doping ratio, we suggested that the enhancement of the current efficiency should be due to the charge transport balance improvement induced by assist dopant in EML.展开更多
This paper considers an eigenvalue problem containing small stochastic processes. For every fixed is, we can use the Prufer substitution to prove the existence of the random solutions lambda(n) and u(n) in the meaning...This paper considers an eigenvalue problem containing small stochastic processes. For every fixed is, we can use the Prufer substitution to prove the existence of the random solutions lambda(n) and u(n) in the meaning of large probability. These solutions can be expanded in epsilon regularly, and their correction terms can be obtained by solving some random linear differential equations.展开更多
The development of high-performance non-fullerene acceptors with extended exciton diffusion lengths has positioned the sequential layer-by-layer(LBL)solution processing technique as a promising approach for fabricatin...The development of high-performance non-fullerene acceptors with extended exciton diffusion lengths has positioned the sequential layer-by-layer(LBL)solution processing technique as a promising approach for fabricating high-performance and large-area organic solar cells(OSCs).This method allows for the independent dissolution and deposition of donor and acceptor materials,enabling precise morphology control.In this review,we provide a comprehensive overview of the LBL processing technique,focusing on the morphology of the active layer.The swelling intercalation phase-separation(SIPS)model is introduced as the mainstream theory of morphology evolution,with a detailed discussion on vertical phase separation.We summarize recent strategies for morphology optimization.Additionally,we review the progress in LBL-based large-area device and module fabrication,as well as green processing approaches.Finally,we highlight current challenges and future prospects,paving the way for the commercialization of LBL-processed OSCs.展开更多
High-efficiency phosphorescent materials serve as the cornerstone for the advancement of organic lightemitting diodes(OLEDs).It is well-established that the incorporation of nitrogen heterocycles and the modulation of...High-efficiency phosphorescent materials serve as the cornerstone for the advancement of organic lightemitting diodes(OLEDs).It is well-established that the incorporation of nitrogen heterocycles and the modulation of structural rigidity and conjugation can enhance the electron transfer capability and luminous efficiency of the complexes,which are indispensable for achieving high-performance devices.In this study,we report three iridium(III)complexes,namely(4-tfmptp)_(2)Ir(pic),(4-tfmptp)_(2)Ir(3-ppca),and(4-tfmptp)_(2)Ir(3-iqca).These complexes feature the rigid 4-tfmptp(4-[4-(trifluoromethyl)phenyl]thieno[2,3-d]pyrimidine)as the primary ligand,with pic(picolinic acid),3-ppca(pyrrolo[1,2-c]pyrimidine-3-carboxylic acid),and 3-iqca(isoquinoline-3-carboxylic acid)as the auxiliary ligands,respectively.In comparison to the complex(4-tfmptp)_(2)Ir(pic)based on the classic auxiliary ligand pic,the emission peaks of(4-tfmptp)_(2)Ir(3-ppca)and(4-tfmptp)_(2)Ir(3-iqca)remain largely unchanged,at around 568 nm.However,their photoluminescence quantum yields(PLQYs)in CH_(2)Cl_(2) improve remarkably,increasing from 53.6%to 93.6%and 97.2%,respectively.Furthermore,solution-processed OLEDs based on(4-tfmptp)_(2)Ir(3-ppca)and(4-tfmptp)_(2)Ir(3-iqca)exhibited exceptional device performances,with maximum current efficiencies of 74.2 and 91.4 cd A^(−1),and maximum external quantum efficiencies(EQE_(max))of 27.8%and 31.4%,respectively.These results suggest the modification of auxiliary ligand can affect the photophysical properties of the Ir(III)complexes greatly.展开更多
In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4(CZTSSe),they have rarely been demonstrated due to the difficulty in im...In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4(CZTSSe),they have rarely been demonstrated due to the difficulty in implementing solution-processed perovskite top cell on the rough surface of the bottom cells.Here,we firstly demonstrate an efficient monolithic two-terminal perovskite/CZTSSe tandem solar cell by significantly reducing the surface roughness of the electrochemically deposited CZTSSe bottom cell.The surface roughness(R_(rms))of the CZTSSe thin film could be reduced from 424 to 86 nm by using the potentiostatic mode rather than using the conventional galvanostatic mode,which can be further reduced to 22 nm after the subsequent ion-milling process.The perovskite top cell with a bandgap of 1.65 eV could be prepared using a solution process on the flattened CZTSSe bottom cell,resulting in the efficient perovskite/CZTSSe tandem solar cells.After the current matching between two subcells involving the thickness control of the perovskite layer,the best performing tandem device exhibited a high conversion efficiency of 17.5%without the hysteresis effect.展开更多
The recent steady improvements in the performance of the nascent hybrid perovskite photovoltaic(PV)devices have led to power conversion efficiencies that rival the best-performing established PV technologies.However,t...The recent steady improvements in the performance of the nascent hybrid perovskite photovoltaic(PV)devices have led to power conversion efficiencies that rival the best-performing established PV technologies.However,to scale these laboratory demonstrations to PV module-scale production will require development of scalable deposition methods for perovskite thin films.Every record result for perovskite PVs so far was achieved via spin coating,a technique that is popular in research laboratories for thin-film coating over relatively small device areas,but not considered to be a method that could be used to scale up the manufacturing of perovskite PVs.Significantly larger thin-film areas are needed for future commercial PV products.Hence,some researchers have focused their efforts on perovskite deposition techniques that can be considered as scalable for mass production and have achieved notable results even on large areas.Here,we present an overview of the solution-based and vapor-based deposition processes;we explain their influence on the molecular crystal growth behavior of perovskite thin films and discuss the morphology as well as other material quality characteristics.By presenting a comprehensive comparison of the deposition techniques and the corresponding performance parameters for different device sizes,we intent to guide the growing research community through the methods that might enable mass production of perovskite solar products.展开更多
An acidic solution based method towards flexible lithium ion battery(LIB)cathodes is developed in this work with perylene diimide(PDI)as the electroactive component and carbon cloth(CC)as the current collector.In this...An acidic solution based method towards flexible lithium ion battery(LIB)cathodes is developed in this work with perylene diimide(PDI)as the electroactive component and carbon cloth(CC)as the current collector.In this approach,PDI is firstly dispersed in concentrated sulfuric acid(H2S04)and then deposited on CC substrate after the dilution of H2S04,which provides an organic solvent-free strategy to construct integrated LIB cathodes.The acdic solution based fabrication process also allows the facile adjusting of loading amounts of PDI in the cathodes,which can effectively influence the battery performances of the PDI/CC cathodes.As the result,the acidic solution processed PDI/CC cathode can deliver a high specific capacity of-36 mAh·g^-1 at the current density of 50 mA·g^-1 in both half cell with lithium foil as anode and full cell with pre-lithiated CC as anode.In both types of the batteries,the PDI/CC cathodes show good cycling stabilities by retaining^84%of the initial capacities after 300 charge-discharge cycles at 500 mA·g^-1.Additionally,the excellent mechanical stability of the PDI/CC cathode enables the LIBs in pouch cell to maintain the electrochemical performances under various bending states,demonstrating their potentials for flexible LIBs.展开更多
文摘Jingwei Intelligent Textile Machinery Co.,Ltd.is a globally leading enterprise in the R&D and manufacturing of textile machinery,affiliated with China National Machinery Industry Group(SINOMACH).As the first modern textile machinery manufacturing base in New China,the company has developed over 70 years to establish a full lifecycle service capability of"machines+components+services+modifications."Its core products,such as Ring Spinning Frames and Combers,feature internationally advanced technologies.With products exported to over 40 countries and regions,the company is committed to providing global customers with intelligent,green textile equipment and full-process solutions.
基金supported by the Cluster of Excellence‘Engineering of Advanced Materials’(EAM)at the University of Erlangen-Nurembergthe support of the EU-project SOLPROCEL(‘Solution processed high performance transparent organic photovoltaic cells’,Grant No.604506)+2 种基金the financial support from the China Scholarship Council(CSC)the financial support from the South China University of Technology and Deutscher Akademischer Austausch Dienst(DAAD)the financial support through the‘Aufbruch Bayern’initiative of the state of Bavaria.
文摘Electroluminescent devices based on organic semiconductors have attracted significant attention owing to their promising applications in flat-panel displays.The conventional display pixel consisting of side-by-side arrayed red,green and blue subpixels represents the mature technology but bears an intrinsic deficiency of a low pixel density.Constructing an individual color-tunable pixel that comprises vertically stacked subpixels is considered an advanced technology.Although color-tunable organic light-emitting diodes(OLEDs)have been fabricated using the vacuum deposition of small molecules,the solution processing of conjugated polymers would enable a much simpler and inexpensive manufacturing process.Here we present the all-solution processing of color-tunable OLEDs comprising two vertically stacked polymer emitters.A thin layer of highly conducting and transparent silver nanowires is introduced as the intermediate charge injection contact,which allows the emission spectrum and intensity of the tandem devices to be seamlessly manipulated.To demonstrate a viable application of this technology,a 4-by-4 pixelated matrix color-tunable display was fabricated.
基金supported by the 973 Program (No. 2014CB643503)National Natural Science Foundation of China (Nos. 51373150, 51461165301)+1 种基金Zhejiang Province Natural Science Foundation (No. LZ13E030002)Fundamental Research Funds for the Central Universities
文摘Field-effect transistors（FETs） of three diketopyrrolopyrroles（DPP）-based small molecules, 3,6-bis（5-phenylthiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolopyrrole-1,4-dione（PDPPP）, 3,6-bis（5-（4-fluorophenyl）thiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolo pyrrole-1,4-dione（FPDPPPF） and 3,6-bis（5-（4-n-butylphenyl）thiophene-2-yl）-2,5-bis（2-ethylhexyl）pyrrolo pyrrole-1,4-dione（Bu PDPPPBu）, have been studied in this work. Well aligned crystals of the three molecules were grown from para-xylene by droplet-pinned crystallization method. FETs based on these aligned crystals exhibit a hole mobility up to0.19 cm^2 V 1s 1and electron mobility up to 0.008 cm^2 V 1s 1. The achieved hole mobility is of the same order of magnitude as reported highest hole mobility for DPP-based small molecules, but it is much lower than that of the high-performance DPP-based polymers. The relative low mobility is mainly attributed to the rough crystal surfaces with steps and, thus, non-smooth charge transport channels at the interfaces between the crystals and the dielectrics. This work has implications for understanding the low charge mobility of DPP-based small molecules.
基金The authors acknowledge funding from the National Natural Science Foundation of China(61974150 and 51773213)Key Research Program of Frontier Sciences,CAS(QYZDB-SSW-JSC047)+1 种基金the Fundamental Research Funds for the Central Universities,the CAS-EU S&T cooperation partner program(174433KYSB20150013)the Natural Science Foundation of Ningbo(2018A610135).
文摘Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.
基金financial support of the Colombia Scientific Program within the framework of the call Ecosistema Cientifíco (Contract FP44842-218-2018)。
文摘Perovskite solar cells(PSCs) have revolutionized photovoltaic research. As a result, a certified power conversion efficiency(PCE) of 25.5% was recorded in late 2020. Although this efficiency is comparable with silicon solar cells;some issues remain partially unsolved, such as lead toxicity, instability of perovskite materials under continuous illumination, moisture and oxygen, and degradation of the metallic counter electrodes. As an alternative to tackle this last concern, carbon materials have been recently used, due to their good electrical and thermal conductivity, and chemical stability, which makes them one of the most promising materials to replace metallic counter electrodes in the fabrication of PSCs. This review highlights the recent advances of carbon-based PSCs, where the carbon electrode(CE) is the main actor.CEs have become very promising candidates for PSCs;they are mainly fabricated using a simple combination of graphite and carbon black powders embedded in a binder matrix, giving a paste that is then solution-processable, resulting in devices with improved quality stability, when compared to metallic electrodes. In this review, CE’s composition is emphasized, since it can give both, high and lowtemperature processed electrodes, compatible with different device configurations. Finally, the tendencies and opportunities to use CE in PSCs devices are presented.
基金supported by the National Natural Science Foundation of China(Nos.42007178 and 41907327)the Natural Science Foundation of Hubei(Nos.2020CFB463 and 2019CFB372)+4 种基金China Geological Survey(Nos.DD20160304 and DD20190824)Fundamental Research Funds for the Central Universities(Nos.CUG 190644 and CUGL180817)National Key Research and Development Program(No.2019YFC1805502)Key Laboratory of Karst Dynamics,MNR and GZAR(Institute of Karst Geology,CAGS)Guilin(No.KDL201703)Key Laboratory of Karst Ecosystem and Treatment of Rocky Desertification,MNR and IRCK by UNESCO(No.KDL201903)。
文摘To investigate groundwater flow and solute transport characteristics of the karst trough zone in China,tracer experiments were conducted at two adjacent typical karst groundwater flow systems(Yuquandong(YQD)and Migongquan(MGQ))in Sixi valley,western Hubei,China.Highresolution continuous monitoring was utilized to obtain breakthrough curves(BTCs),which were then analyzed using the multi-dispersion model(MDM)and the two-region nonequilibrium model(2RNE)with basic parameters calculated by CXTFIT and QTRACER2.Results showed that:(1)YQD flow system had a complex infiltration matrix with overland flow,conduit flow and fracture flow,while the MGQ flow system was dominated by conduit flow with fast flow transport velocity,but also small amount of fracture flow there;(2)They were well fitted based on the MDM(R^2=0.928)and 2RNE(R^2=0.947)models,indicating that they had strong adaptability in the karst trough zone;(3)conceptual models for YQD and MGQ groundwater systems were generalized.In YQD system,the solute was transported via overland flow during intense rainfall,while some infiltrated down into fissures and conduits.In MGQ system,most were directly transported to spring outlet in the fissureconduit network.
基金Project supported by the National Key Research and Development Program of China(2016YFB0700903)the National Natural Science Foundation of China(5159088251401054)。
文摘It is confirmed that phase homogenization is very important for improving the magnetic properties of 2:17-type Sm-Co sintered magnets,In this work,the influence of solid solution process on microstructure and magnetic properties of the Sm(CobalFe0.233Cu0.073Zr0.024)7.6 sintered magnets was systematically studied.With the solid-solution treating duration(tS)increasing from 0 to 4 h,intrinsic coercivity(Hcj)increases from 12.83 to 36.54 kOe,magnetic field at knee-point(Hknee)increases from2.76 to 19.14 kOe,and the maximum energy product increases from 19.79 to 29.48 MGOe.The electron probe microanalyzer results reveal that there mainly exist gray and dark regions besides"white"rare earth-rich phase,and the conte nt of Sm,Fe and Cu elements for the two kinds of regions changes a lot for the specimens,Furthermore,with tS increasing up to 4 h,the elements content deviation between the gray and dark regions becomes small gradually from 3.94 at%to 0.27 at%,7.66 at%to 0.21 at%and 7.27 at%to 0.16 at%for Sm,Fe and Cu elements,respectively.Moreover,transmission electron microscopy results show that the distribution of cell size is much more concentrated for aged specimens when tS is 4 h.It is also found that the Cu concentration at cell boundaries for the 4 h solid-solution treatment case shows relatively higher values and greater concentration gradient(1.94 at%/nm).It is verified that sufficient solution treatment duration is prerequisite to form these homogeneous microstructural features,which are the key points for obtaining both high Hcj and Hknee.
基金Projects(51673214,51673218,61774170)supported by the National Natural Science Foundation of ChinaProject(2017YFA0206600)supported by the National Key Research and Development Program of China。
文摘Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.
基金supported by the National Natural Science Foundation of China (Nos.51773029,52073040 and 51821002)the Fundamental Research Funds for the Central Universities (No.ZYGX2016Z010)the International Cooperation and Exchange Project of Science and Technology Department of Sichuan Province (No.2019YFH0057)。
文摘Thermally activated delayed fluorescent(TADF) materials capable of efficient solution-processed nondoped organic light-emitting diodes(OLEDs) are of important and practical significance for further development of OLEDs. In this work, a new electron-donating segment, 2,7-di(9 H-carbazol-9-yl)-9,9-dimethyl-9,10-dihydroacridine(2 Cz-DMAC), was designed to develop solution-processable non-doped TADF emitters. 2 Cz-DMAC can not only simultaneously increase the solubility of compounds and suppress harmful aggregation-caused quenching, but also efficiently broaden the delocalization of the highest occupied molecular orbital and promote the reverse intersystem crossing process. Three new TADF emitters, 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)dibenzo[b,d]thiophene 5,5-dioxide(2 Cz-DMAC-BTB), 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)-9 H-thioxanthen-9-one(2 Cz-DMAC-TXO), 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)thianthrene 5,5,10,10-tetraoxide(2 Cz-DMAC-TTR), were developed by using 2 Cz-DMAC segment as the electron-donor. As anticipated, the solution-processed non-doped OLEDs employing 2 Cz-DMAC-BTB, 2 Cz-DMAC-TXO and 2 CzDMAC-TTR as the emitters respectively exhibited green, orange and red emissions with maximum external quantum efficiencies of 14.0%, 6.6% and 2.9%. These results successfully demonstrate the feasibility and convenience of developing efficient solution-processable non-doped TADF emitters based on 2 CzDMAC segment.
基金financially supported by the National Natural Science Foundation of China (Nos.21674060,21274087,61674102,and 61334008)National Key R&D Program (No.2016YFB0401100)
文摘A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics. Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoided. The photo-cross-linker, BBP-4, was added into host polymers by simple solution blending process, which was capable of abstracting hydrogen atoms from polymers containing active C--H groups upon exposure to ultraviolet （UV） radiation. The cross-linking can be completed with a relatively long wavelength UV light （365 nm）. The approach has been applied to methacrylate and styrenic polymers such as commercial poly（methylmethacrylate） （PMMA）, poly（iso-butylmethacrylate） （PiBMA） and poly（4-methylstyrene） （PMS）. The cross-linked networks enhanced dielectric properties and solvent resistance of the thin films. The bottom-gate organic field-effect transistors （OFETs） through all solution processes on plastic substrate were fabricated. The OFET devices showed low voltage operation and steep subthreshold swing at relatively small gate dielectric capacitance.
基金the financial support from the National Natural Science Foundation of China(No.21473192)the financial support from the National Natural Science Foundation of China(Nos.21373042 and 21677029)
文摘All-inorganic cesium lead halide perovskites （CsPbX3, X=CF, Br-, I-） could provide comparableoptoelectronic properties as a promising class of materials for photovoltaic cell （PV）, photodetector andlight-emitting diode （LED） with enhanced thermal and moisture stabilities compared to organic-inorganic lead halide species. However, fabrication of CsPbI3 perovskite via facile solution process hasbeen difficult due to instability of CsPbl3 in the perovskite cubic phase in ambient air. Herein, we reportthe synthesis of CsPbl3 perovskite microcrystals by low-temperature, catalyst-free, solution-phasemethod. By applying the time-resolve spectroscopic technique, we determine the carrier diffusioncoefficient of 0.6-1.2 cm2/s, the intrinsic carrier lifetimes of 200-1300 ns and diffusion length of4-10 μm in different individual CsPbl3 perovskite microcrystals. Our results suggest the CsPbl3 perovskitemicrocrystals synthesized by solution process exhibit high quality feature and are suitable forapplications in optoelectronic devices.
基金This project is supported by National Natural Science Foundation of China(No.50575209).
文摘The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have been proved to be troublesome and less intuitive. Analytical solutions based on loss-less tube model and average friction tube model are found respectively by using fluid net theory, and they fit the experimental results well. The research work shows that： Fluid net theory can be used to solve the analytical solution of filling and exhausting processes of pneumatic system, and the result of loss-less tube model is close to that of average friction model, so loss-less tube model is recommended since it is simpler, and the difference between filling time and exhausting time is determined by initial and final pressures, the volume of container and the section area of tube, and has nothing to do with the length of the tube.
基金financially supported by the National Natural Science Foundation of China(Nos.52073282,52122309,51833009 and 21975247)the CAS-Croucher Funding Scheme for Joint Laboratories:Poly U-CIAC Joint Laboratory(No.121522KYSB20200040)the Open Project of State Key Laboratory of Supramolecular Structure and Materials(No.sklssm2023019)。
文摘Three carbazole-based multiple resonance dendrimers namely D1-BNN,D2-BNN and D3-BNN,are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs)by introducing the first-,second-,and third-generation carbazole dendrons in periphery of boron,nitrogen-doped polycyclic aromatic hydrocarbon skeleton.Different from D1-BNN containing first-generation carbazole dendron showing moderate photoluminescent quantum efficiency(PLQY)of 68%in solid state and broadened emission bands with full-width at half maximum(FWHM)increasing from 26 nm to 34 nm upon doping concentration growing from 10 wt%to 40 wt%,D3-BNN with the third-generation carbazole dendron exhibits high PLQY of 92%and weak dependence of photoluminescent spectra on doping concentration,which can remain narrowband emissions with unchanged FWHM of 24 nm at same doping concentration range.Solution-processed OLEDs employing D3-BNN as emitter reveal blue electroluminescence at 477 nm with FWHM of 24 nm,and maximum external quantum efficiency(EQE)of 17.3%which is kept at 14.4%at doping concentration of 40 wt%,much superior than the D1-BNN devices showing maximum EQE of 13.0%that drops to 3.7%at 40 wt%doping concentration.
基金supported by the National High Technology Research and Development Program of China (No.2012AA011901)the National Program on Key Basic Research Project of China (No.2012CB723406)+2 种基金the National Natural Science Foundation of China (No.51573036)the Fundamental Research Funds for the Central Universities of China (No.JD2016JGPY0007)the Industry-University-Research Cooperation Project of Aviation Industry Corporation of China (No.CXY2013HFGD20)。
文摘In this paper, co-doping method is used to improve the current efficiency of solution-processed organic light-emitting diodes(OLEDs). By changing the ratio of two thermally activated delayed fluorescent(TADF) emitters, we studied the performance of device and its mechanism. A solution processed OLED with a structure of indium tin oxide(ITO, 150 nm)/PEDOT:PSS(30 nm)/CBP:4 Cz IPN-x%:4 Cz PN-y%(30 nm)/TPBi(40 nm)/Li F(1 nm)/Al(100 nm) was fabricated. The current efficiencies of 26.6 cd/A and 26.4 cd/A were achieved by the devices with dopant ratio of 6% 4 Cz IPN:2% 4 Cz PN and 2% 4 Cz IPN:6% 4 Cz PN in emitting material layer(EML), respectively. By investigating the tendency of current density change in devices with different doping ratio, we suggested that the enhancement of the current efficiency should be due to the charge transport balance improvement induced by assist dopant in EML.
文摘This paper considers an eigenvalue problem containing small stochastic processes. For every fixed is, we can use the Prufer substitution to prove the existence of the random solutions lambda(n) and u(n) in the meaning of large probability. These solutions can be expanded in epsilon regularly, and their correction terms can be obtained by solving some random linear differential equations.
基金Project(22408404)supported by the National Natural Science Foundation of China。
文摘The development of high-performance non-fullerene acceptors with extended exciton diffusion lengths has positioned the sequential layer-by-layer(LBL)solution processing technique as a promising approach for fabricating high-performance and large-area organic solar cells(OSCs).This method allows for the independent dissolution and deposition of donor and acceptor materials,enabling precise morphology control.In this review,we provide a comprehensive overview of the LBL processing technique,focusing on the morphology of the active layer.The swelling intercalation phase-separation(SIPS)model is introduced as the mainstream theory of morphology evolution,with a detailed discussion on vertical phase separation.We summarize recent strategies for morphology optimization.Additionally,we review the progress in LBL-based large-area device and module fabrication,as well as green processing approaches.Finally,we highlight current challenges and future prospects,paving the way for the commercialization of LBL-processed OSCs.
基金supported by the National Natural Science Foundation of China(22365035,52203231)Yunnan Province Xingdian Talent Support Program for Young Talents,Expert Workstation in Yunnan Province(202405AF140035)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2021A1515110478)Shenzhen University Stability Support Program Project(20220818172424009)。
文摘High-efficiency phosphorescent materials serve as the cornerstone for the advancement of organic lightemitting diodes(OLEDs).It is well-established that the incorporation of nitrogen heterocycles and the modulation of structural rigidity and conjugation can enhance the electron transfer capability and luminous efficiency of the complexes,which are indispensable for achieving high-performance devices.In this study,we report three iridium(III)complexes,namely(4-tfmptp)_(2)Ir(pic),(4-tfmptp)_(2)Ir(3-ppca),and(4-tfmptp)_(2)Ir(3-iqca).These complexes feature the rigid 4-tfmptp(4-[4-(trifluoromethyl)phenyl]thieno[2,3-d]pyrimidine)as the primary ligand,with pic(picolinic acid),3-ppca(pyrrolo[1,2-c]pyrimidine-3-carboxylic acid),and 3-iqca(isoquinoline-3-carboxylic acid)as the auxiliary ligands,respectively.In comparison to the complex(4-tfmptp)_(2)Ir(pic)based on the classic auxiliary ligand pic,the emission peaks of(4-tfmptp)_(2)Ir(3-ppca)and(4-tfmptp)_(2)Ir(3-iqca)remain largely unchanged,at around 568 nm.However,their photoluminescence quantum yields(PLQYs)in CH_(2)Cl_(2) improve remarkably,increasing from 53.6%to 93.6%and 97.2%,respectively.Furthermore,solution-processed OLEDs based on(4-tfmptp)_(2)Ir(3-ppca)and(4-tfmptp)_(2)Ir(3-iqca)exhibited exceptional device performances,with maximum current efficiencies of 74.2 and 91.4 cd A^(−1),and maximum external quantum efficiencies(EQE_(max))of 27.8%and 31.4%,respectively.These results suggest the modification of auxiliary ligand can affect the photophysical properties of the Ir(III)complexes greatly.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government's Ministry of Science and ICT(NRF-2022M3J1A1063226,2021M3H4A1A 03057403,2017M3D1A1039377,and NRF-2021R1C1C1011882)supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20203040010320)
文摘In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4(CZTSSe),they have rarely been demonstrated due to the difficulty in implementing solution-processed perovskite top cell on the rough surface of the bottom cells.Here,we firstly demonstrate an efficient monolithic two-terminal perovskite/CZTSSe tandem solar cell by significantly reducing the surface roughness of the electrochemically deposited CZTSSe bottom cell.The surface roughness(R_(rms))of the CZTSSe thin film could be reduced from 424 to 86 nm by using the potentiostatic mode rather than using the conventional galvanostatic mode,which can be further reduced to 22 nm after the subsequent ion-milling process.The perovskite top cell with a bandgap of 1.65 eV could be prepared using a solution process on the flattened CZTSSe bottom cell,resulting in the efficient perovskite/CZTSSe tandem solar cells.After the current matching between two subcells involving the thickness control of the perovskite layer,the best performing tandem device exhibited a high conversion efficiency of 17.5%without the hysteresis effect.
基金funded by the MIT-Tata Grid Edge Solar research program
文摘The recent steady improvements in the performance of the nascent hybrid perovskite photovoltaic(PV)devices have led to power conversion efficiencies that rival the best-performing established PV technologies.However,to scale these laboratory demonstrations to PV module-scale production will require development of scalable deposition methods for perovskite thin films.Every record result for perovskite PVs so far was achieved via spin coating,a technique that is popular in research laboratories for thin-film coating over relatively small device areas,but not considered to be a method that could be used to scale up the manufacturing of perovskite PVs.Significantly larger thin-film areas are needed for future commercial PV products.Hence,some researchers have focused their efforts on perovskite deposition techniques that can be considered as scalable for mass production and have achieved notable results even on large areas.Here,we present an overview of the solution-based and vapor-based deposition processes;we explain their influence on the molecular crystal growth behavior of perovskite thin films and discuss the morphology as well as other material quality characteristics.By presenting a comprehensive comparison of the deposition techniques and the corresponding performance parameters for different device sizes,we intent to guide the growing research community through the methods that might enable mass production of perovskite solar products.
基金supported by the National Natural Science Foundation of China(Nos.61575121,51772189,21772120,21774072,and 21720102002).
文摘An acidic solution based method towards flexible lithium ion battery(LIB)cathodes is developed in this work with perylene diimide(PDI)as the electroactive component and carbon cloth(CC)as the current collector.In this approach,PDI is firstly dispersed in concentrated sulfuric acid(H2S04)and then deposited on CC substrate after the dilution of H2S04,which provides an organic solvent-free strategy to construct integrated LIB cathodes.The acdic solution based fabrication process also allows the facile adjusting of loading amounts of PDI in the cathodes,which can effectively influence the battery performances of the PDI/CC cathodes.As the result,the acidic solution processed PDI/CC cathode can deliver a high specific capacity of-36 mAh·g^-1 at the current density of 50 mA·g^-1 in both half cell with lithium foil as anode and full cell with pre-lithiated CC as anode.In both types of the batteries,the PDI/CC cathodes show good cycling stabilities by retaining^84%of the initial capacities after 300 charge-discharge cycles at 500 mA·g^-1.Additionally,the excellent mechanical stability of the PDI/CC cathode enables the LIBs in pouch cell to maintain the electrochemical performances under various bending states,demonstrating their potentials for flexible LIBs.
