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- 摘要
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- 实验方案
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Printed Higha??Density and Flexible Photodetector Arrays via Sizea??matched Heterogeneous Microa??/Nanostructure
摘要： Semiconductor/metal binary systems constitute the core components in electronic/photonic devices. The domain size of the heterostructure should be comparable to the charge diffusion length for superior photoelectric response. However, the fabrication of size-matched heterostructures is still a challenge, especially for printed devices. Here, a high-density photodetector array with lateral semiconductor/metal heterostructure is achieved via the template-assisted sequentially printing strategy. The Ag/PBDB-T:ITIC/Ag based lateral heterojunction that matches the charge diffusion length in the charge transfer process provides high light response sensitivity (D* = 3.41 × 1012 Jones, R = 12.9 A W?1). Moreover, the printed pixel interval can be decreased to 10 μm (106 pixels cm?2; resolution: 2.5 × 103 dpi). As the printing strategy can be implemented on soft substrates, the photodetector arrays are endowed with the flexibility. This work demonstrates a simple and effective strategy for chip-scale fabrication of flexible high-performance photodetectors, which validates the potential of printed heterogeneous micro-/nanostructures for integrated active electronics and optics.
关键词： flexible photodetector arrays,light imaging,sequential printing,heterostructures
更新于2025-09-23 15:21:01
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Molecular-Level Control over Plasmonic Properties in Silver Nanoparticle/Self-Assembling Peptide Hybrids
摘要： The plasmonic properties of silver nanoparticle (AgNP) arrays are directly controlled by AgNP size, shape, and spatial arrangement. Reported here is a strategy to prepare chiral AgNP arrays templated by two constitutionally isomeric aromatic peptide amphiphiles (APAs), KS C′EKS and C′EKSKS (KS = S-aroylthiooxime-modi?ed lysine, C′ = citrulline, and E = glutamic acid). In phosphate bu?er, both APAs initially self-assembled into nanoribbons with a similar geometry. However, in the presence of silver ions and poly(sodium 4-styrenesulfonate) (PSSS), one of the nanoribbons (KS C′EKS) turned into nanohelices with a regular twisting pitch, while the other (C′EKSKS) remained as nanoribbons. Both were used as templates for synthesis of arrays of ～8 nm AgNPs to understand how small changes in molecular structure a?ect the plasmonic properties of these chiral AgNP/APA hybrids. Both hybrids showed improved colloidal stability compared to pure AgNPs, and both showed enhanced sensitivity as surface-enhanced Raman spectroscopy (SERS) substrates for model analytes, with nanohelices showing better SERS performance compared to their nanoribbon counterparts and pure AgNPs.
关键词： self-assembling peptide,silver nanoparticle,plasmonic properties,chiral AgNP arrays,SERS
更新于2025-09-23 15:21:01
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CFD Simulation of Turbulent Wind Effect on an Array of Ground-Mounted Solar PV Panels
摘要： Aim of the present study is to determine the wind loads on the PV panels in a solar array since panels are vulnerable to high winds. Extensive damages of PV panels, arrays and mounting modules have been reported the world over due to high winds. Solar array of dimension 6 m 9 4 m having 12 PV panels of size 1 m 9 2 m on 3D 1:50 scaled models have been simulated using unsteady solver with Reynolds-Averaged Navier–Stokes equations of computational ?uid dynamics techniques to study the turbulent wind effects on PV panels. A standalone solar array with 30(cid:3) tilt angle in atmospheric surface layer with the Renormalized Group (RNG) turbulence closure sub-jected to incident wind varied from - 90(cid:3) to 90(cid:3). The net pressure, drag and lift coef?cients are found to be maxi-mum when the wind is ?owing normally to the PV panel either 90(cid:3) or - 90(cid:3). The tilt angle of solar arrays the world over not vary on the latitude but also on the seasons. Keeping this in mind the ground mounted PV panels in array with varying tilt angle from 10(cid:3) to 60(cid:3) at an interval of 10(cid:3) have been analyzed for normal wind incident i.e. 90(cid:3) and - 90(cid:3) using unsteady RNG turbulence model. Net pressure coef?cients have been calculated and found to be increasing with increase in array tilting angle. Maximum net pressure coef?cient was observed for the 60(cid:3) tilted PV array for 90(cid:3) and - 90(cid:3) wind incident having value of 0.938 and 0.904 respectively. The results can be concluded that the PV panels are subjected to signi?cant lift and drag forces under wind loading, which needs to be quanti?ed with suf?cient factor of safety to avoid damages.
关键词： Wind loads,CFD,Unsteady RNG turbulence model,Solar arrays
更新于2025-09-23 15:21:01
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Mesoporous black TiO2 array employing sputtered Au cocatalyst exhibiting efficient charge separation and high H2 evolution activity
摘要： The separation and transfer of photogenerated carriers are the key issue in the design of high performance TiO2 photocatalysts. In order to overcome the kinetic limitations and achieve rapid charge transfer, TiO2-related multi-component catalysts have been extensively studied. Among all the TiO2 supports, the impressive black TiO2 (BT) with broad visible light absorption spectrum and oxygen vacancies are preferable, but still suffers from low quantum efficiency. Meanwhile, poor control of cocatalyst placement by conventional loading method can also severely impede photocatalytic efficiency. Herein a fast and simple metal magnetron sputter approach was used to place highly-uniformed Au nanoparticles cocatalyst on the top of the mesoporous TiO2-BT nanotube array fabricated by in situ electrochemical anodization approach on a Ti film. This confined plasmonic photocatalyst with highly uniformly distributed Au cocatalysts exhibited greatly enhanced charge-separation and charge-transfer behavior, and a remarkable 10 times enhancement of the photocatalytic H2 evolution reactivity over conventional TiO2 nanotube. The TiO2-BT-Au electron transfer cascade structure is proposed in which black TiO2 acts as a buffer layer for TiO2 conduction band electrons, allowing efficient photogenerated electrons to be transferred to Au nanoparticles and then into the TiO2 pores that suitable for H2 generation. Since the nanotube walls themselves are curved upwards, the short diffusion length allows electrons to be easily transferred to the cocatalyst, where recombination of photogenerated electron pairs is limited. The metal magnetron sputter technique for noble metal cocatalyst immobilization and the unique TiO2-BT-Au electron-transfer system are promising and can be extended to the design of other supported catalysts.
关键词： Metal magnetron sputter,TiO2 nanotube arrays,Oxygen vacancies,Hydrogen evolution,Au nanoparticle,Black TiO2
更新于2025-09-23 15:21:01
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A Selfa??Powered Higha??Performance UV Photodetector Based on Corea??Shell GaN/MoO <sub/>3a??</sub><i> <sub/>x</sub></i> Nanorod Array Heterojunction
摘要： Self-powered UV photodetectors are highly desirable for applications in space communications and environmental monitoring. However, most self-powered UV photodetectors exhibit unimpressive performance in weak signal detection. Herein, a self-powered UV photodetector based on the core–shell GaN/MoO3–x nanorod array (NRA) heterojunction system is demonstrated. Homogeneous MoO3–x layers are deposited on GaN NRAs by a simple one-step physical vapor deposition method. The photodetector device shows an ultrahigh specific detectivity of 2.7 × 1015 Jones at 355 nm without any power supply. Further analyses reveal a responsivity of 160 A W?1 and a high UV–vis rejection ratio (R355 nm/R400 nm) of 2.0 × 104 under zero bias. The self-powered device also has a fast response speed with a rise/fall time of 73/90 μs. As a result, the self-powered photodetector, featuring ultrahigh detectivity and responsivity along with fast response, exhibits great potential for applications in next-generation UV detection. The core–shell NRA structure heterojunction design provides a valuable direction for realizing nanoscale self-powered UV photodetectors.
关键词： core–shell nanorod arrays,UV photodetectors,ultrahigh detectivity,self-powered devices
更新于2025-09-23 15:21:01
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Boosting Perovskite Photodetector Performance in NIR Using Plasmonic Bowtie Nanoantenna Arrays
摘要： Triple-cation mixed metal halide perovskites are important optoelectronic materials due to their high photon to electron conversion efficiency, low exciton binding energy, and good thermal stability. However, the perovskites have low photon to electron conversion efficiency in near-infrared (NIR) due to their weak intrinsic absorption at longer wavelength, especially near the band edge and over the bandgap wavelength. A plasmonic functionalized perovskite photodetector (PD) is designed and fabricated in this study, in which the perovskite ((Cs0.06FA0.79MA0.15)Pb(I0.85Br0.15)3) active materials are spin-coated on the surface of Au bowtie nanoantenna (BNA) arrays substrate. Under 785 nm laser illumination, near the bandedge of perovskite, the fabricated BNA-based plasmonic PD exhibits ≈2962% enhancement in the photoresponse over the Si/SiO2-based normal PD. Moreover, the detectivity of the plasmonic PD has a value of 1.5 × 1012 with external quantum efficiency as high as 188.8%, more than 30 times over the normal PD. The strong boosting in the plasmonic PD performance is attributed to the enhanced electric field around BNA arrays through the coupling of localized surface plasmon resonance. The demonstrated BNA-perovskite design can also be used to enhance performance of other optoelectronic devices, and the concept can be extended to other spectral regions with different active materials.
关键词： near infrared,bowtie nanoantenna arrays,perovskite photodetectors,localized surface plasmon resonance
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE 5G World Forum (5GWF) - Silicon Valley, CA, USA (2018.7.9-2018.7.11)] 2018 IEEE 5G World Forum (5GWF) - Feasibility and Challenges of Over-The-Air Testing for 5G Millimeter Wave Devices
摘要： The evolution from 1G through 5G cellular technologies has been fueled mainly by the insatiable need for speed, lower latency, high reliability and enhanced flexibility of use across the wireless ecosystem. Using multiple antennas in conjunction with complex modulation schemes has rendered each generation of cellular technology an enhanced version over its former counterpart. 5G technology aims to exploit previously unchartered higher millimeter wave (mmWave) frequencies & larger bandwidths towards realizing the goal of greater data throughput, while simultaneously enhancing data reliability and reducing latency. The small wavelength of mmWave signals makes it possible to design 5G devices using several multi-element phased array antennas with small element-element spacing. However, unlike the antenna designs of 2G/3G/4G devices, 5G multi-element antennas would be integrated with the radio frequency integrated circuit (RFIC) board of the 5G device. The tight integration between antennas and RFIC renders the antenna port of the device under test (DUT) inaccessible for physical connections using cables/connectors to test equipment. Since conducted testing with cables is not feasible anymore, radiated over-the-air (OTA) testing becomes mandatory for 5G mmWave device verification. This paper aims to assess the feasibility of candidate OTA test methods for 5G mmWave test requirements. The challenges of testing 5G mmWave devices over-the-air have been elucidated and alternative OTA test solutions for overcoming these challenges have also been discussed.
关键词： multi-probe anechoic chamber (MPAC),Multiple-input multiple-output (MIMO),compact antenna test range (CATR),far-field,near-field,antenna arrays
更新于2025-09-23 15:21:01
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[IEEE 2018 3rd Russian-Pacific Conference on Computer Technology and Applications (RPC) - Vladivostok (2018.8.18-2018.8.25)] 2018 3rd Russian-Pacific Conference on Computer Technology and Applications (RPC) - Modeling of a Solar Arrays Deployment Process at Ground Tests of Mechanical Devices on Active Gravity Compensation Systems
摘要： This paper focuses on the modeling of a spacecraft solar arrays deployment process in ground tests of mechanical devices on the active gravity compensation systems. The ground tests are carried out on the test workbenches. Such workbenches provide a gravity compensation of the solar arrays in the deployment process in order to simulate the space weightlessness conditions. The passive gravity compensation systems with cable suspensions for moving parts of the solar array are the most widespread at nowadays. The gravity compensation of the passive workbenches for the large size and heavy solar arrays could differ significantly from the space weightlessness conditions because of the “added mass effect”. For this reason, an active gravity compensation workbench was created by ISS-Reshetnev Company order [1]. In the active gravity compensation system, the trolleys are equipped with tracking systems, which hold the suspension cable on vertical position with high accuracy during the solar array deployment and the tensile (compensation) forces in the cables supported by automatic control systems at desired levels. The modeling of dynamics of the solar arrays transformable elements and the active gravity compensation system mobile devices was implemented in Matlab Simulink with creating mechanical component models at SolidWorks and other.
关键词： weightlessness environment,deployable solar arrays,zero-gravity,ground test,gravity compensation system
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE AUTOTESTCON - National Harbor (Oxon Hill), MD, USA (2018.9.17-2018.9.20)] 2018 IEEE AUTOTESTCON - Spread Spectrum Time Domain Reflectometry for Complex Impedances: Application to PV Arrays
摘要： Spread spectrum time domain reflectometry (SSTDR) has previously been used for detection and location of intermittent faults on live electrical wiring. These intermittent faults can be open circuits, short circuits, or resistive changes, all of which preserve the original shape of the SSTDR correlated waveform. But things are very different when SSTDR encounters a complex impedance discontinuity such as a capacitor or inductor. In this case, the reflection is a function of frequency, changing the shape of the SSTDR signature. In this paper, we will show the SSTDR response to single capacitors and inductors. We will also explore how SSTDR responds to arrays of PV panels (which are capacitive) connected by wires. We will show both simulations and measurements. In some configurations, it is relatively easy to see faults, although algorithms are still under development. In other configurations, little change occurs, which makes it very difficult to create a system for testing for these faults.
关键词： Inductance,Complex impedances,Capacitance,Photovoltaic (PV) arrays,Spread spectrum time domain reflectometry (SSTDR)
更新于2025-09-23 15:21:01
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Mm-Wave Beam-Steering Focal Plane Arrays with Microfluidically Switched Feed Networks
摘要： Micro?uidically switched feed networks are introduced to realize millimeter-wave beam-steering focal plane arrays (FPAs). Switching functionality is achieved by a selectively metallized plate (SMP) repositionable within a micro?uidic channel that is brought in close proximity to the microstrip line feed network of an FPA. The feed network is strategically designed to exhibit gap discontinuities that are sequentially overlapped by the SMP metallizations. The capacitive couplings between the SMP metallizations and the gap discontinuities are designed to achieve wideband (～20 GHz) switching functionality with low insertion loss (IL < 0.2 dB). Transmission line theory is utilized to demonstrate that the feed network offers 38% fractional bandwidth with ≤7 dB IL for linear arrays of 32 elements. This performance constitutes a signi?cant improvement over the recently reported resonant feed network based realization of micro?uidic beam-steering FPAs (MFPAs). Experimental veri?cation is carried out through the design and fabrication of a 30 GHz eight-element FPA. The FPA exhibits measured gains ranging between 20.2 and 22.6 dBi. Loss budget breakdown con?rms the low-loss performance of the micro?uidically switched feed networks (≤3 dB). The required micro?uidic actuation range is 4.2 mm and 10× lower than that of the prior work. This allows to achieve a faster beam-steering speed (0.27 s versus 5.25 s of previous designs). An integrated sensing approach for detecting the SMP position is also presented for the ?rst time to facilitate the use of presented MFPAs with closed-loop position control.
关键词： milimeter-wave,micro?uidics,focal plane arrays (FPAs),Ka-band,recon?gurable antenna,Beam-steering
更新于2025-09-23 15:21:01