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Solutiona??Processed Polymer Solar Cells with over 17% Efficiency Enabled by an Iridium Complexation Approach
摘要: The commercially available PM6 as donor materials are used widely in highly efficient nonfullerene polymer solar cells (PSCs). In this work, different concentrations of iridium (Ir) complexes (0, 0.5, 1, 2.5, and 5 mol%) are incorporated carefully into the polymer conjugated backbone of PM6 (PM6-Ir0), and a set of π-conjugated polymer donors (named PM6-Ir0.5, PM6-Ir1, PM6-Ir2.5, and PM6-Ir5) are synthesized and characterized. It is demonstrated that the approach can rationally modify the molecular aggregations of polymer donors, effectively controlling the corresponding blend morphology and physical mechanisms, and finally improve the photovoltaic performance of the PM6-Irx-based PSCs. Among them, the best device based on PM6-Ir1:Y6 (1:1.2, w/w) exhibits outstanding power conversion efficiencies (PCEs) of 17.24% tested at Wuhan University and 17.32% tested at Institute of Chemistry, Chinese Academy of Sciences as well as a certified PCE of 16.70%, which are much higher than that of the control device based on the PM6-Ir0:Y6 blend (15.39%). This work affords an effective approach for further break through the reported champion PCE of the binary PSCs.
关键词: iridium complexation,morphology,polymer solar cells,power conversion efficiency
更新于2025-09-23 15:19:57
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Effect of laser beam incidence angle on cladding morphology in laser cladding process
摘要: The change of angle θ between laser cladding powder plane and substrate plane will lead to changes in cladding layer's geometric morphology. Therefore, we established a quantitative numerical prediction model for cladding layer geometry. In this model, we consider the variation of θ, the laser energy attenuation rate and the temperature rise of the powder particles. At the same time, the simulation results were verified by experiments. The results show that when θ is in the range of 50°~90°, the initial temperature is 298 K, the scanning speed is 3.75 mm/s, and the laser spot diameter is 4.5 mm, the Fe#1 powder cladding can achieve better forming effect on Q235. In general, with the decrease of θ, the height of the cladding layer decreases and the width of the layer increases. However, when θ is less than 50°, the quality of the formed morphology significantly deteriorated. The experimental results are in good agreement with the simulation results, which verifies the validity and reliability of the model. This work provides a theoretical reference for further understanding the relationship between the laser cladding morphology and the incident angle.
关键词: Numerical simulation,Laser cladding,Geometric morphology,Laser incident angle
更新于2025-09-23 15:19:57
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Effect of purification on the electrical properties of transparent conductive films fabricated from single-walled carbon nanotubes
摘要: Transparent conductive films (TCFs) made of single-walled carbon nanotubes (SWCNTs) are usually fabricated using highly pure SWCNTs. Obtaining pure SWCNTs is an important step for harnessing their excellent electrical properties. Herein, we studied the effect of purification of SWCNTs by thermal and acid processes on the electrical properties of TCFs. These purification processes also affected the length and diameter of the SWCNT bundles. The purity of SWCNTs was determined by UV–visible-near-infrared spectroscopy and the metal content by thermogravimetric analysis. TCFs were made by spraying aqueous suspensions of SWCNTs having different purities onto polyethylene terephthalate substrates, and the ratios of dc to optical conductivities of the films were compared. Thermally purified (TP) SWCNT TCFs had a higher ratio than thermally and acid-purified (TAP) ones even though the purity of the TP-SWCNTs was lower than that of the TAP-SWCNTs. The conducting paths of the SWCNT bundle networks in the TP-SWCNT TCFs were well organized, because nanosized graphitic nanoparticles and metal catalysts occupied the spaces between the CNT bundles or networks without hindering the network connections. Although the SWCNT purity affected the conductivity of the SWCNT TCFs, the network property of lower junction resistance with smaller bundle diameter was more influential on film conductivity.
关键词: Transparent conductive films,Film network morphology,Purification,Single-walled carbon nanotubes,Purity evaluation
更新于2025-09-23 15:19:57
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Effects of a Fluorinated Donor Polymer on the Morphology, Photophysics, and Performance of All-Polymer Solar Cells based on Naphthalene Diimide-Arylene Copolymer Acceptors
摘要: Naphthalene diimide (NDI)-biselenophene copolymer (PNDIBS) and NDI-selenophene copolymer (PNDIS) and the fluorinated donor polymer PM6 were used to investigate how a fluorinated polymer component affects the morphology and performance of all-polymer solar cells (all-PSCs). Although the PM6:PNDIBS blend system exhibits a high open-circuit voltage (Voc = 0.925 V) and desired low optical bandgap energy loss (Eloss = 0.475 eV), the overall power conversion efficiency (PCE) was 3.1%. In contrast, PM6:PNDIS blends combine a high Voc (0.967 V) with a high fill factor (FF = 0.70) to produce efficient all-PSCs with 9.1% PCE. Furthermore, the high performance PM6:PNDIS all-PSCs could be fabricated by various solution processing approaches and at active layer thickness as high as 300 nm without compromising photovoltaic efficiency. The divergent photovoltaic properties of PNDIS and PNDIBS when paired respectively with PM6 are shown to originate from the starkly different blend morphology and blend photophysics. Efficient PM6:PNDIS blend films were found to exhibit a vertical phase stratification along with lateral phase separation while the molecular packing had a predominant face-on orientation. Bulk lateral phase separation with both face-on and edge-on molecular orientations featured in the poor performing PM6:PNDIBS blend films. Enhanced charge photogeneration and suppressed geminate and bimolecular recombinations with 99% charge collection probability found in PM6:PNDIS blends strongly differ from the poor charge collection probability (66%) and high electron-hole pair recombination seen in PM6:PNDIBS. Our findings demonstrate that beyond the generally expected enhancement of Voc, a fluorinated polymer component in all-PSCs can also exert a positive or negative influence on photovoltaic performance via the blend morphology and blend photophysics.
关键词: Naphthalene Diimide-Arylene Copolymer,Fluorinated donor polymer,Vertical phase stratification,All-polymer solar cells,Thick-film active layer,Blend Morphology
更新于2025-09-23 15:19:57
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Numerical simulation of the surface morphology and residual stress field of IN718 alloy by Gaussian mode laser shock
摘要: Laser shock processing (LSP) is a new surface modification technology that can improve mechanical properties and extending fatigue life. The numerical simulation was utilized in this work, the IN718 alloy was treated by Gaussian mode laser with the laser pulse energy of 3?7 J, laser pulse width of 12 ns and laser spot in diameter of 3 mm. And the effects of laser pulse energy on the surface morphology and residual stress field of material was investigated. The numerical simulation results showed that after the treatment of LSP, the plastic deformation and compressive residual stress layer with a certain depth is formed on the near surface of material. The amount of the plasticity deformation of material was increased with the laser pulse energy. And the compressive residual stress in surface and the direction of depth are increased with the laser pulse energy too. With the laser pulse energy from 3?7 J, the maximum compressive residual stresses are appeared at the center of the surface corresponding to the laser spot. When the laser pulse energy is increased from 3 J–7 J, the plastic deformation in depth is increases from 0.50 μm–1.86 μm, and the maximum compressive residual stress is increased from 362 MPa–742 MPa. In conclusion, LSP can improve mechanical properties of IN718 significantly, and the laser pulse energy is the most important factor to affect the LSP effect. This work can provide a certain theoretical guidance for researchers to study the IN718 alloy treated by LSP.
关键词: Residual stress,Gaussian mode laser,Surface morphology,Laser shock processing,IN718 alloy,Laser pulse energy,Numerical simulation
更新于2025-09-23 15:19:57
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Realizing high detectivity organic photodetectors in visible wavelength by doping highly ordered polymer PCPDTBT
摘要: A new method for realizing the response broadening of organic photodetectors (OPDs) using highly ordered polymer PCPDTBT doping has been proposed in this paper. The effects of PCPDTBT doping on the optical and electrical properties of OPDs were investigated experimentally. It was found that when the mass ratio of PTB7:PCPDTBT:PC61BM was 8.5:1.5:15, the response spectrum of the OPDs was broadened to 380–830 nm. The responsivity (R) and external quantum efficiency (EQE) of the OPDs reached 396, 244, 189 mA/W and 78%, 57%, 51% under 630, 530 and 460 nm illumination and (cid:0) 1 V bias, respectively, and the detectivity (D*) reached 1011 Jones. The results showed that the addition of PCPDTBT to PTB7:PC61BM increased the absorption of light at 700–830 nm. At the same time, the addition of PCPDTBT promotes the exciton dissociation interface in the active layer from the original one to the current three, they are PTB7:PCPDTBT, PTB7:PC61BM and PCPDTBT:PC61BM, which increase the probability of exciton dissociation in the active layer. In addition, the addition of highly ordered polymer PCPDTBT promotes the crystallization of the film and optimizes the carrier transport of the film. These synergistic effects promote the photocurrent of the OPDs.
关键词: Ternary bulk heterojunction,Exciton dissociation,Organic photodetectors,Microscopic morphology
更新于2025-09-23 15:19:57
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Micro-scale Precision Control of a Computer Assisted Transoral Laser Microsurgery System
摘要: The path opening is a ?lter that preserves bright regions in the image in which a path of a certain length L ?ts. A path is a (not necessarily straight) line de?ned by a speci?c adjacency relation. The most ef?cient implementation known scales as O(min(L, d, Q)N) with the length of the path, L, the maximum possible path length, d, the number of graylevels, Q, and the image size, N. An approximation exists (parsimonious path opening) that has an execution time independent of path length. This is achieved by preselecting paths, and applying 1D openings along these paths. However, the preselected paths can miss important structures, as described by its authors. Here, we propose a different approximation, in which we preselect paths using a grayvalue skeleton. The skeleton follows all ridges in the image, meaning that no important line structures will be missed. An H-minima transform simpli?es the image to reduce the number of branches in the skeleton. A graph-based version of the traditional path opening operates only on the pixels in the skeleton, yielding speedups up to one order of magnitude, depending on image size and ?lter parameters. The edges of the graph are weighted in order to minimize bias. Experiments show that the proposed algorithm scales linearly with image size, and that it is often slightly faster for longer paths than for shorter paths. The algorithm also yields the most accurate results— as compared with a number of path opening variants—when measuring length distributions.
关键词: Path opening,line segment,mathematical image analysis,granulometry,unbiased,morphology,length distribution
更新于2025-09-23 15:19:57
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a??Double-Acceptor-Typea?? Random Conjugated Terpolymer Donors for Additive-Free Non-Fullerene Organic Solar Cells
摘要: Random conjugated terpolymers (RCTs) not only promote great comprehension and realization for state-of-the-art high effective non-fullerene polymer solar cells (OSCs) but also offer a simple and practical synthetic strategy. However, the photovoltaic properties of RCTs yet lagged behind that of the donor-acceptor alternating copolymer, especially in the additive-free devices. Hence, we developed two feasible “double acceptor type” random conjugated terpolymers, PBDB-TAZ20 and PBDB-TAZ40. The additive-free OSCs based on PBDB-TAZ20:ITIC and PBDB-TAZ40:ITIC exhibit decent efficiencies of 12.34% and 11.27%, respectively, which both surpass the PBDB-T:ITIC-based device. For the RCTs, the reasonably weakened crystallinity and reduced phase separation degree are demonstrated to help improve charge transport, reduce bimolecular recombination and thus enhance the photovoltaic performance of the additive-free OSCs. The results imply that adding a third moiety into the D-A polymer donors provides a simple but efficient synthetic approach for high-performance OSCs.
关键词: polymer solar cells,crystallinity,non-fullerenes,morphology,random terpolymers
更新于2025-09-23 15:19:57
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Efficient Organic Solar Cell with 16.88% Efficiency Enabled by Refined Acceptor Crystallization and Morphology with Improved Charge Transfer and Transport Properties
摘要: Single-layered organic solar cells (OSCs) using nonfullerene acceptors have reached 16% efficiency. Such a breakthrough has inspired new sparks for the development of the next generation of OSC materials. In addition to the optimization of electronic structure, it is important to investigate the essential solid-state structure that guides the high efficiency of bulk heterojunction blends, which provides insight in understanding how to pair an efficient donor–acceptor mixture and refine film morphology. In this study, a thorough analysis is executed to reveal morphology details, and the results demonstrate that Y6 can form a unique 2D packing with a polymer-like conjugated backbone oriented normal to the substrate, controlled by the processing solvent and thermal annealing conditions. Such morphology provides improved carrier transport and ultrafast hole and electron transfer, leading to improved device performance, and the best optimized device shows a power conversion efficiency of 16.88% (16.4% certified). This work reveals the importance of film morphology and the mechanism by which it affects device performance. A full set of analytical methods and processing conditions are executed to achieve high efficiency solar cells from materials design to device optimization, which will be useful in future OSC technology development.
关键词: multilength-scaled morphology,nonfullerene acceptors,power conversion efficiency,organic solar cells,2D electron transport
更新于2025-09-23 15:19:57
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Performance improvement of polymer solar cells with binary additives induced morphology optimization and interface modification simultaneously
摘要: Active layer morphology optimization and electrode buffer layer interface modification are commonly used strategies in improving the performance of polymer solar cells (PSCs). In this study, we prepared PTB7: PC71BM bulk heterojunction PSCs with 1,8-diiodooctane (DIO) and polyethylene glycol (PEG) additives, and studied the influence of binary additives on exciton dissociation, charge transport and charge extraction. DIO facilitates donor/acceptor phase separation for efficient exciton dissociation and charge transport. The migration of PEG from active layer to the PEDOT:PSS layer improves the crystallinity of PTB7, optimizes charge transport pathway, and enhances the conductivity of PEDOT:PSS layer. With the combined advantages of binary additives in active layer morphology optimization and anode buffer layer modification, the device exhibits a high short-circuit current density of 20.03 mA/cm2 and an improved power conversion efficiency. Binary additive provides a promising method to optimize active layer morphology and improve interfacial buffer layer of PSCs simultaneously.
关键词: Charge extraction,Charge transport,Binary additive,Polymer solar cells,Morphology,Interface modification
更新于2025-09-23 15:19:57