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- 摘要
- 关键词
- 实验方案
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POWER-COMBINED MULTIPLIERS AT 60 GHZ BASED ON FUNDAMENTAL FREQUENCY VECTOR MODULATION
摘要： High output power multiplier is necessary for local oscillator (LO) source of millimeter-wave and terahertz applications. However, single multiplier chip power-handling capability is limited by understandably low efficiency level and other technical constraints. Conventional in-phase power-combined structures are sensitive to the fabrication and assembly errors. In order to circumvent these limits, we propose a power-combined multiplier architecture at 60 GHz based on fundamental frequency vector modulation at 30 GHz. The fundamental vector modulator adjustment can compensate the phase deviation at the two doubler output ports despite fabrication and assembly tolerances. We can increase the output power by approximately 3 dB compared with single multiplier without sacrificing the bandwidth.
关键词： fabrication and assembly tolerances,power-combined multiplier,60 GHz,fundamental frequency vector modulation
更新于2025-09-23 15:21:01
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Assembly of Conductive Polyaniline Microstructures by a Laser-Induced Microbubble
摘要： Micro-patterns of conductive polymers are key for various applications in the fields of flexible electronics and sensing. A bottom-up method that allows high-resolution printing without additives is still lacking. Here, such a method is presented based on micro-printing by the laser-induced microbubble technique (LIMBT). Continuous micro-patterning of polyaniline (PANI) was achieved from a dispersion of the Emeraldine base form of PANI (EB-PANI) in n-methyl-2-pyrrolidone (NMP). A focused laser beam is absorbed by the EB-PANI nanoparticles and leads to formation of a microbubble, followed by convection currents, which rapidly pin EB-PANI nanoparticles to the bubble/substrate interface. Micro-Raman spectra confirmed that the printed patterns preserve the molecular structure of EB-PANI. A simple transformation of the printed lines to the conducting Emeraldine salt form of PANI (ES-PANI) was achieved by doping with various acid solutions. The hypothesized deposition mechanism was verified, and the resulting structures were characterized by microscopic methods. The micro-structures displayed conductivity of 3.8×10-1 S/cm upon HCl doping and 1.5×10-1 S/cm upon H2SO4 doping, on par with state-of-the-art patterning methods. High fidelity control over the width of the printed lines down to ~650 nm was accomplished by varying the laser power and microscope stage velocity. This straightforward bottom-up method using low power lasers offers an alternative to current microfabrication techniques.
关键词： laser printing,nanoparticle assembly,polyaniline,microbubble,directed assembly
更新于2025-09-23 15:19:57
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Lasera??Induced Graphene for Electrothermally Controlled, Mechanically Guided, 3D Assembly and Humana??Soft Actuators Interaction
摘要： Mechanically guided, 3D assembly has attracted broad interests, owing to its compatibility with planar fabrication techniques and applicability to a diversity of geometries and length scales. Its further development requires the capability of on-demand reversible shape reconfigurations, desirable for many emerging applications (e.g., responsive metamaterials, soft robotics). Here, the design, fabrication, and modeling of soft electro-thermal actuators based on laser-induced graphene (LIG) are reported and their applications in mechanically guided 3D assembly and human-soft actuators interaction are explored. Over 20 complex 3D architectures are fabricated, including reconfigurable structures that can reshape among three distinct geometries. Also, the structures capable of maintaining 3D shapes at room temperature without the need for any actuation are realized by fabricating LIG actuators at an elevated temperature. Finite element analysis can quantitatively capture key aspects that govern electrothermally controlled shape transformations, thereby providing a reliable tool for rapid design optimization. Furthermore, their applications are explored in human-soft actuators interaction, including elastic metamaterials with human gesture-controlled bandgap behaviors and soft robotic fingers which can measure electrocardiogram from humans in an on-demand fashion. Other demonstrations include artificial muscles, which can lift masses that are about 110 times of their weights and biomimetic frog tongues which can prey insects.
关键词： human-soft actuators interaction,laser-induced graphene,electrothermal actuators,3D assembly
更新于2025-09-23 15:19:57
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Spontaneously Selfa??Assembly of a 2D/3D Heterostructure Enhances the Efficiency and Stability in Printed Perovskite Solar Cells
摘要： As perovskite solar cells (PSCs) are highly efficient, demonstration of high-performance printed devices becomes important. 2D/3D heterostructures have recently emerged as an attractive way to relieving the film inhomogeneity and instability in perovskite devices. In this work, a 2D/3D ensemble with 2D perovskites self-assembled atop 3D methylammonium lead triiodide (MAPbI3) via a one-step printing process is shown. A clean and flat interface is observed in the 2D/3D bilayer heterostructure for the first time. The 2D perovskite capping layer significantly suppresses nonradiative charge recombination, resulting in a marked increase in open-circuit voltage (VOC) of the devices by up to 100 mV. An ultrahigh VOC of 1.20 V is achieved for MAPbI3 PSCs, corresponding to 91% of the Shockley–Queisser limit. Moreover, notable enhancement in light, thermal, and moisture stability is obtained as a result of the protective barrier of the 2D perovskites. These results suggest a viable approach for scalable fabrication of highly efficient perovskite solar cells with enhanced environmental stability.
关键词： stability,2D/3D heterojunctions,self-assembly,perovskite solar cells,high efficiency
更新于2025-09-23 15:19:57
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Prospects of Coupled Organica??Inorganic Nanostructures for Charge and Energy Transfer Applications
摘要： We review the field of organic-inorganic nanocomposites with a focus on materials that exhibit a significant degree of electronic coupling across the hybrid interface. These nanocomposites undergo a variety of charge and energy transfer processes, enabling optoelectronic applications in devices which exploit singlet fission, triplet energy harvesting, photon upconversion or hot charge carrier transfer. We discuss the physical chemistry of the most common organic and inorganic components. Based on those we derive synthesis and assembly strategies and design criteria on material and device level with a focus on photovoltaics, spin memories or optical upconverters. We conclude that future research in the field should be directed towards an improved understanding of the binding motif and molecular orientation at the hybrid interface.
关键词： Inorganic Nanostructures,Self-Assembly,Organic π-Systems,Optoelectronic Devices,Plasmonics
更新于2025-09-23 15:19:57
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Self-assembled electrodes based on polyaniline grafted with reduced graphene oxide and polystyrene sulfonate
摘要： In this work, composites based on polyaniline (PAni) grafted with reduced graphene oxide (rGO) were obtained by the in situ chemical polymerization of aniline with rGO (mass ratio of 1 and 2.5%) dispersed into the monomer solutions. PAni and its PAni-rGO composites were used to prepare self-assembled (SA) films by depositing them onto indium tin oxide (ITO) substrates with alternating layers of polystyrene sulfonate (PSS). The structure and morphology of the materials were characterized by Fourier-transform infrared spectroscopy (FT-IR), RAMAN spectroscopy, and scanning electron microscopy (SEM). The oxidation states of PAni and its PAni-rGO composites were characterized by cyclic voltammetry (CV) and UV-Vis spectroscopy during the SA procedure. The electrochemical behavior of the obtained SA films was also characterized by electrochemical impedance spectroscopy (EIS). The EIS results showed a significant decrease in the polarization resistance (Rp), from 1020 to 302 Ω, for the film with 1% of rGO (PAni-1%rGO/PSS) when compared with its unmodified counterpart (PAni/PSS). The synergic effects observed for the PAni-1%rGO/PSS film showed that controlling the rGO mass ratio plays an important role in the improvement of the charge transfer processes, and that this electrode has potential for electrochemical applications, such as sensors and charge storage devices.
关键词： Conducting polymer composites,Polyaniline,Reduced graphene oxide,Self-assembly
更新于2025-09-23 15:19:57
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Negative Differential Resistance and Hysteresis in Selfa??Assembled Nanoscale Networks with Tunable Moleculea??toa??Nanoparticle Ratios
摘要： Electronic transport is investigated through self-assembled benzenedithiol–gold nanoparticle networks with tunable molecule-to-particle ratios (1:5–50:1) deposited between planar electrodes. Two-terminal current–voltage measurements of the networks display linear behavior at low bias, which is described using a circuit model that accounts for different network morphologies, tunable via molecule-to-nanoparticle ratio, and defects. At larger biases, nonlinear negative differential resistance and hysteresis behavior are observed for different molecular concentrations, which can be attributed to a combination of ?eld-assisted tunneling and charge trapping occurring in the nanoscale networks. The directed self-assembly of benzenedithiol–metal nanoparticle molecular electronic networks is suggested for molecular integrated circuits in applications such as memory, switching, hardware security, and computing.
关键词： molecules,electronic transport,self-assembly,negative differential resistance,nanoparticles
更新于2025-09-23 15:19:57
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Decoration of porous silicon with gold nanoparticles via layer-by-layer nano-assembly for interferometric and hybrid photonic/plasmonic (bio)sensing
摘要： Gold nanoparticle layers (AuNPLs) enable the coupling of morphological, optical, and electrical properties of gold nanoparticles (AuNPs) with tailored and specific surface topography, making them exploitable in many bio-applications (e.g. biosensing, drug delivery, photothermal therapy). Herein, we report the formation of AuNPLs on porous silicon (PSi) interferometers and distributed Bragg reflectors (DBRs) for (bio)sensing applications via layer-by-layer (LbL) nano-assembling of a positively charged polyelectrolyte, namely polyallylamine hydrochloride (PAH), and negatively charged citrate-capped AuNPs. Decoration of PSi interferometers with AuNPLs enhances the Fabry-Perot fringe contrast due to increased surface reflectivity, resulting in an augmented sensitivity for both bulk and surface refractive index sensing, using NaCl aqueous solutions to infiltrate the pores (roughly 4.5-fold), in the former, and unspecific bovine serum albumin (BSA) adsorption on the pore surface (roughly 2.6-fold), in the latter. Sensitivity enhancing is also confirmed for affinity and selective biosensing of streptavidin (roughly 2.5-fold) using a biotinylated polymer, namely, negatively-charged poly(methacrylic acid) (b-PMAA). Further, decoration of PSi DBR with AuNPLs envisages building up a hybrid photonic/plasmonic optical sensing platform. Indeed, both photonic (DBR stop-band) and plasmonic (localized surface plasmon resonance, LSPR) peaks of the hybrid structure are sensitive to changes of bulk refractive index (using 35% glucose aqueous solutions) and BSA unspecific adsorption. To the best of our knowledge, this is the first report about the formation of AuNPLs via LbL nano-assembly on PSi for i) the enhancing of the interferometric performance in (bio)sensing applications and ii) the building up of hybrid photonic/plasmonic platforms for sensing and perspective biosensing applications.
关键词： Layer-by-Layer (LbL) nano-assembly,Porous Silicon (PSi),Biosensor,Interferometer,Gold nanoparticles (AuNPs),Hybrid Photonic/Plasmonic,Distribute Bragg Reflector (DBR),Sensor
更新于2025-09-23 15:19:57
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Enhanced Ordering and Efficient Photoalignment of Nanostructures in Block Copolymers Enabled by Halogen Bond
摘要： Fabrication and manipulation of macroscopically ordered nanostructures in polymer ?lms via supramolecular self-organization are fascinating from the viewpoints of science and technology. Here, a halogen bond (XB) was introduced into a block copolymer to facilitate its microphase separation process upon XB-driven supramolecular self-assembly. To the best of our knowledge, this is an extremely rare example to elegantly maneuver nanostructures of polymers by the emerging supramolecular interaction, XB. The nonmesogenic block copolymer composed of poly(ethylene oxide) and azopyridine-containing polymethacrylate was transformed into a supramolecular liquid-crystalline polymer through the halogen-bonded interaction between 1,2-diiodo-3,4,5,6-tetra?uorobenzene and the azopyridine group with the optimal molar ratio of 1:1. For comparison, one hydrogen-bonded liquid-crystalline polymer was also fabricated but no such ordering enhancement was acquired, indicating that both the high directionality of XB and the resulting supramolecular mesogenic ordering played key roles in the enhanced ordering of nanostructures in polymer ?lms. In addition, e?cient photoalignment and photoreorientation of nanostructures coinciding with the oriented direction of the supramolecular mesogens were also obtained by manipulating photoirradiation of linearly polarized light for the present XB-involved liquid-crystalline block copolymer, which is promising for the development of a novel generation of advanced composite liquid crystal (LC) materials.
关键词： halogen bond,supramolecular self-assembly,photoalignment,block copolymer,nanostructures
更新于2025-09-23 15:19:57
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Room-Temperature Electrically Pumped InP-based $1.3\boldsymbol{\mu} \mathbf{m}$ Quantum Dot Laser on on-axis (001) Silicon
摘要： We present a method for quantifying a risk for killer defects at layer level and estimating yield for substrate packages using information from design ?les. To calculate risk ranks and predicted yield, we de?ne a risk distance that is a key parameter extracted from designs using image processing techniques. In order to validate our model, we analyze two different designs, each having multiple layers, and compare with data from baseline lots. It is shown that there is an inverse correlation between risk layer ranks and yield. Estimated yield based on our model is compared with baseline yield for four layers of the second design. The model-to-baseline yield difference is less than 1% for three layers we tested.
关键词： yield estimation,assembly,circuit analysis,metrology sampling,Yield prediction,integrated circuit packaging
更新于2025-09-23 15:19:57