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Well‐Defined Cu <sub/>2</sub> O/Cu <sub/>3</sub> (BTC) <sub/>2</sub> Sponge Architecture as Efficient Phenolics Scavenger: Synchronous Etching and Reduction of MOFs in confined‐pH NH <sub/>3</sub> ?H <sub/>2</sub> O
摘要： Fabrication of low-dimensional nano-MOFs as well as nanoparticles/metal-organic frameworks (MOFs) hybrids has sparked new scientific interests but remains a challenging task. Taking Cu3(BTC)2 as a proof of concept, it is demonstrated thats NH3?H2O solution of a confined pH value can readily shape the bulk Cu3(BTC)2 into nanoscale Cu3(BTC)2, beyond the need to control the crystal growth kinetics of MOFs. Adjusting the pH of NH3?H2O within a much small range (10–11) allows fine tuning over the size and shape of nanoscale Cu3(BTC)2. Particularly at pH = 11, NH3?H2O exhibits weak reducibility that triggers a reduction of part of Cu3(BTC)2 into Cu2O, while shaping the other into Cu3(BTC)2 nanowires. Benefiting from the coincidence of reduction and etching effects, the newly generated Cu2O dots can in situ anchor onto adjacent Cu3(BTC)2 nanowires at highly dispersive state, forming a well-defined sponge-like architecture built of Cu2O dots and nano-Cu3(BTC)2. The CuOx derived from annealing of the Cu2O dots/nano-Cu3(BTC)2 hybrid preserves the sophisticated sponge architecture and high porosity, and exhibits promising applications in phenol scavenging, with efficiency outperforming its counterparts and many other Cu-based catalysts reported in literature. It is anticipated that the findings here pave the way for the rational design of intricate nano-MOFs in a more efficient way.
关键词： nanoparticles/MOF,etching and reduction,sponge architecture,synergistic effect,low-dimensional MOFs
更新于2025-11-14 17:03:37
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[IEEE 2018 25th International Conference on Mechatronics and Machine Vision in Practice (M2VIP) - Stuttgart, Germany (2018.11.20-2018.11.22)] 2018 25th International Conference on Mechatronics and Machine Vision in Practice (M2VIP) - Vehicle and Pedestrian Recognition Using Multilayer Lidar based on Support Vector Machine
摘要： Moving-object tracking (estimating position and velocity of moving objects) is a key technology for autonomous driving systems and driving assistance systems in mobile robotics and vehicle automation domains. To predict and avoid collisions, the tracking system has to recognize objects as accurately as possible. This paper presents a method for recognizing vehicles (cars and bicyclists) and pedestrians using multilayer lidar (3D lidar). Lidar data are clustered, and eight-dimensional features are extracted from each of clustered lidar data, such as distance from the lidar, velocity, object size, number of lidar-measurement points, and distribution of reflection intensities. A multiclass support vector machine is applied to classify cars, bicyclists, and pedestrians from these features. Experiments using “The Stanford Track Collection” data set allow us to compare the proposed method with a method based on the random forest algorithm and a conventional 26-dimensional feature-based method. The comparison shows that the proposed method improves recognition accuracy and processing time over the other methods. Therefore, the proposed method can work well under low computational environments.
关键词： multiclass classification,support vector machine,low-dimensional features,multilayer lidar,object recognition
更新于2025-09-23 15:22:29
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A Strategy toward New Low-Dimensional Hybrid Halide Perovskites with Anionic Spacers
摘要： The low-dimensional halide perovskites have received enormous attention due to their unique photovoltaic and optoelectronic performances. Periodic spacers are used to inhibit the growth of 3D perovskite and fabricate a 2D counterpart with layered structure, mostly based on organic/inorganic cations. Herein, by introducing organic anions (e.g., pentanedioic acid (PDA) and hexanedioic acid (HDA) simultaneously), leaf-shaped (Cs3Pb2Br5)2(PDA–HDA) microplates with low-dimensional structure are synthesized. They also exhibit significant photoluminescence (PL) centered at 540 nm with a narrow emission peak. The synthesis of single crystals of Pb(PDA) and Pb(HDA) allows to further clarify the crystal structure of (Cs3Pb2Br5)2(PDA–HDA) perovskite and its structural evolution mechanism. Moreover, the cooperative introduction of dicarboxylic acid pairs with appropriate lengths is thermodynamically favored for the low-dimensional perovskite crystallization. The temperature-dependent PL indicates a V-shaped Stokes shift with elevated temperature that could be associated with the localization of excitons in the inorganic layers between organic dicarboxylic acid molecules. This work demonstrates low-dimensional halide perovskite with anionic spacers, which also opens up a new approach to the growth of low-dimensional organic–inorganic hybrid perovskite crystals.
关键词： photoluminescence,low-dimensional materials,nanocrystals,halide perovskites
更新于2025-09-23 15:22:29
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Electrode-free anodic oxidation nanolithography of low-dimensional materials
摘要： Scanning probe lithography based on local anodic oxidation (LAO) provides a robust and general nanolithography tool for a wide range of applications. Its practical use, however, has been strongly hampered due to the requirement of a pre-fabricated micro-electrode to conduct the driving electrical current. Here we report a novel electrode-free LAO technique, which enables in-situ patterning of as-prepared low-dimensional materials and heterostructures with great flexibility and high precision. Unlike conventional LAO driven by a DC current, the electrode-free LAO is driven by a high-frequency (>10 kHz) AC current applied through capacitive coupling, which eliminates the need of a contacting electrode and can be used even for tailoring insulating materials. Using this technique, we demonstrated flexible nanolithography of graphene, hexagonal boron nitride (hBN), and carbon nanotubes (CNTs) on insulating substrates with ~10-nanometer precision. In addition, the electrode-free LAO exhibits high etching quality without oxide residues left. Such an in-situ and electrode-free nanolithography with high etching quality opens up new opportunities for fabricating ultraclean nanoscale devices and heterostructures with great flexibility.
关键词： electrode-free local anodic oxidation,graphene,high-frequency AC voltage,low-dimensional materials,Scanning probe lithography
更新于2025-09-23 15:21:21
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Interface passivation treatment by halogenated low-dimensional perovskites for high-performance and stable perovskite photovoltaics
摘要： The voltage loss which is mainly caused by the nonradiative recombination at the interface has played a serious negative effect on the photovoltaic performance of perovskite solar cells (PSCs). Herein, we firstly designed four halogenated layers by the way of employing different benzylammonium-based aromatic cations for high-performance devices. The introduction of halogen functional groups can not only enhance the hydrophobicity but also optimize the photovoltaic characteristics of LDP which play an important role on passivation effect of the interface between perovskite and hole transport materials (HTM) layer. The films with halogenated LDP passivation layers displayed suppressed nonradiative recombination and reduced trap density, leading to significantly reduced voltage loss. As a result, the optimal devices with 4-bromobenzylammonium-based LDP layer achieved the power conversion efficiency (PCE) as high as 21.13% with an enhanced open-circuit voltage (Voc) of 1.14 V. Under the hydrophobic and buffer action of the halogenated LDP layer, the modified devices showed outstanding long-term stability when exposed to moisture, heat and continuous UV irradiation. This work proves the enhanced passivation effect of LDP layer by regulating the chemical property of introduced organic cations for high-performance and stable perovskite photovoltaics.
关键词： Low-dimensional perovskite,Perovskite solar cells,Halogenated cations,Passivation effect,Photovoltaic performance
更新于2025-09-23 15:21:01
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Selfa??Additive Lowa??Dimensional Ruddlesdena??Popper Perovskite by the Incorporation of Glycine Hydrochloride for Higha??Performance and Stable Solar Cells
摘要： The recent rise of low-dimensional Ruddlesden–Popper (RP) perovskites is notable for superior humidity stability, however they suffer from low power conversion efficiency (PCE). Suitable organic spacer cations with special properties display a critical effect on the performance and stability of perovskite solar cells (PSCs). Herein, a new strategy of designing self-additive low-dimensional RP perovskites is first proposed by employing a glycine salt (Gly+) with outstanding additive effect to improve the photovoltaic performance. Due to the strong interaction between CO and Pb2+, the Gly+ can become a nucleation center and be beneficial to uniform and fast growth of the Gly-based RP perovskites with larger grain sizes, leading to reduced grain boundary and increased carrier transport. As a result, the Gly-based self-additive low-dimensional RP perovskites exhibit remarkable photoelectric properties, yielding the highest PCE of 18.06% for Gly (n = 8) devices and 15.61% for Gly (n = 4) devices with negligible hysteresis. Furthermore, the Gly-based devices without encapsulation show excellent long-term stability against humidity, heat, and UV light in comparison to BA-based low-dimensional PSCs. This approach provides a feasible design strategy of new-type low-dimensional RP perovskites to obtain highly efficient and stable devices for next-generation photovoltaic applications.
关键词： low-dimensional perovskites,high-performance solar cells,self-additive effect,stable solar cells,glycine hydrochloride
更新于2025-09-23 15:19:57
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Asymmetric Alkyl Diamine Based Dion-Jacobson Low-Dimensional Perovskite Solar Cells with Efficiency Exceeding 15%
摘要： Low-dimensional (LD) Dion-Jacobson perovskites (DJPs) are showing great potential to solve the stability issue of perovskite solar cells (PSCs). However, it is still a challenge to simultaneously obtain high power conversion efficiency (PCE) and high stability in DJP-LD-PSCs. Here, we present an asymmetric alkyl diammonium 3-(dimethylammonium)-1-propylammonium (DMAPA2+) as spacer cation to resolve this issue. With small adjacent inorganic interlayer distance, PSCs based on LD (DMAPA)MAn-1PbnI3n+1 (n = 1) achieve a PCE of 3.85%, the currently highest PCE for PSCs based on n = 1 LD-DJP. The systematic study of the crystallization kinetics of DJPs with higher n values (n = 3, 4, 5) demonstrate that the perovskite quality is mainly dominated by the formation and decomposition of its intermediate phase. PSCs based on on n = 4 LD-DJP (DMAPA)MA3Pb4I13), with vertical crystal orientation, hierarchical phase distribution and low trap density, yield high PCEs up to 15.16%, and excellent stability with over 90% of the initial PCE retained without encapsulation after being stored at 85 °C in air for 1000 hours and ~80% PCE retained after 300-h of continous operation under 1-sun illumination in air.
关键词： Dion-Jacobson perovskites,perovskite solar cells,asymmetric alkyl diammonium,stability,Low-dimensional,power conversion efficiency
更新于2025-09-23 15:19:57
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Emerging Waveguide Technology || Photonic Crystal Waveguides
摘要： The original results of theoretical and experimental studies and the properties of microwave one-dimensional waveguide photonic crystals have been generalized. Methods for describing the electrodynamic characteristics of photonic crystals and their relationship with the parameters of periodic structures filling the waveguides have been presented. The results of an investigation on the characteristics of microwave waveguide photonic crystals made in the form of dielectric matrices with air inclusions have been presented. The model of effective dielectric permittivity has been proposed for describing the characteristics of the investigated photonic crystals containing layers with a large number of air inclusions. New types of microwave low-dimensional waveguide photonic crystals containing periodically alternating elements that are sources of higher type waves have been described. The possibility of effective control of the amplitude-frequency characteristics of microwave photonic crystals by means of electric and magnetic fields has been analyzed. Examples of new applications of waveguide photonic crystals in the microwave range have been given: the measuring parameters of the materials and semiconductor nanostructures that play the role of the microwave photonic crystals' periodicity defect; the resonators of near-field microwave microscopes; small-sized matched loads for centimeter and millimeter wavelength ranges on the basis of microwave photonic crystals.
关键词： low-dimensional photonic crystal,electrically controlled characteristics,forbidden bands,defect mode,measurement of micro- and nanostructures,microwave matched loads,microwave photonic crystals
更新于2025-09-19 17:13:59
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Progress of Photodetectors Based on the Photothermoelectric Effect
摘要： High-performance uncooled photodetectors operating in the long-wavelength infrared and terahertz regimes are highly demanded in the military and civilian fields. Photothermoelectric (PTE) detectors, which combine photothermal and thermoelectric conversion processes, can realize ultra-broadband photodetection without the requirement of a cooling unit and external bias. In the last few decades, the responsivity and speed of PTE-based photodetectors have made impressive progress with the discovery of novel thermoelectric materials and the development of nanophotonics. In particular, by introducing hot-carrier transport into low-dimensional material–based PTE detectors, the response time has been successfully pushed down to the picosecond level. Furthermore, with the assistance of surface plasmon, antenna, and phonon absorption, the responsivity of PTE detectors can be significantly enhanced. Beyond the photodetection, PTE effect can also be utilized to probe exotic physical phenomena in spintronics and valleytronics. Herein, recent advances in PTE detectors are summarized, and some potential strategies to further improve the performance are proposed.
关键词： thermoelectrics,low-dimensional materials,photothermoelectric effect,photodetectors,nanophotonics
更新于2025-09-19 17:13:59
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High charge carrier mobility in solution processed one-dimensional lead halide perovskite single crystals and their application as photodetectors
摘要： Organic inorganic hybrid metal halide perovskites have emerged as promising candidates for photovoltaics and light-emitting diodes. Recently, interest has been growing in the properties of low-dimensional metal halide perovskites, and one-dimensional versions with strong quantum confinement have demonstrated highly efficient broadband luminescence. Nevertheless, the charge transport mechanism in these low dimensional perovskites remains unclear. In this work, we characterised the charge mobility in one-dimensional perovskite single crystals using a space charge limited current method. Temperature dependent charge mobility measurements indicated that localized polarons at high temperature are replaced by delocalized polarons at low temperature with extended states in the polaronic band. A minimum mobility of 4.51 cm2/Vs was measured at room temperature. UV photodetectors based on these crystals show an ultrahigh photoresponsivity of 132.3 A W-1. These findings show the promise of high mobility low dimensional perovskite materials for optoelectronic applications.
关键词： space charge limited current,low-dimensional,charge transport,photodetectors,organic-inorganic hybrid metal halide perovskites
更新于2025-09-19 17:13:59