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Programmable Spectral Filter in C-Band Based on Digital Micromirror Device
摘要： Optical ?lters have been adopted in many applications such as recon?gurable telecommunication switches, tunable lasers and spectral imaging. However, most of commercialized ?lters based on a micro-electrical-mechanical system (MEMS) only provide a minimum bandwidth of 25 GHz in telecom so far. In this work, the programmable ?lter based on a digital micromirror device (DMD) experimentally demonstrated a minimum bandwidth of 12.5 GHz in C-band that matched the grid width of the International Telecommunication Union (ITU) G.694.1 standard. It was capable of ?ltering multiple wavebands simultaneously and ?exibly by remotely uploading binary holograms onto the DMD. The number of channels and the center wavelength could be adjusted independently, as well as the channel bandwidth and the output power. The center wavelength tuning resolution of this ?lter achieved 0.033 nm and the insertion loss was about 10 dB across the entire C-band. Since the DMD had a high power handling capability (25 KW/cm2) of around 200 times that of the liquid crystal on silicon (LCoS) chip, the DMD-based ?lters are expected to be applied in high power situations.
关键词： digital micromirror device,optical switch,programmable spectral ?lter
更新于2025-11-28 14:23:57
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A portable and universal upconversion nanoparticle-based lateral flow assay platform for point-of-care testing
摘要： Upconversion nanoparticle-based lateral flow assays (UCNP-LFAs) have attracted significant attention in point-of-care testing (POCT) applications, due to the long-term photostability and enhanced signal-to-background noise ratio. The existing UCNP-LFAs generally require peripheral equipment for exciting fluorescent signals and reading out fluorescence results, which are generally bulky and expensive. Herein, we developed a miniaturized and portable UCNP-LFA platform, which is composed of a LFA detection system, an UCNP-LFA reader and a smartphone-assisted UCNP-LFA analyzer. The LFA detection system is based on three types of UCNPs for multiplexed detection. The reader has a dimension of 24.0 cm×9.4 cm×5.4 cm (L×W×H) and weight of 0.9 kg. The analyzer based on the custom-designed software of a smartphone (termed as UCNP-LFA analyzer) can get the quantitative analysis results in a real-time manner. We demonstrated the universality of this platform by highly sensitive and quantitative detections of several kinds of targets, including small molecule (ochratoxin A, OTA), heavy metal ion (Hg2+), bacteria (salmonella, SE), nucleic acid (hepatitis B virus, HBV) and protein (growth stimulation expressed gene 2, ST-2). Our developed UCNP-LFA platform holds great promise for applications in disease diagnostics, environmental pollution monitoring and food safety at the point of care.
关键词： UCNP-based biosensor,telemedicine,point-of-care diagnostics,paper microfluidics,multiplexed detection,miniaturized device
更新于2025-11-28 14:23:57
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Laser transmission welding and surface modification of graphene film for flexible supercapacitor applications
摘要： When a graphene ?lm is coated onto a ?exible polymer substrate, weak adhesion can cause delamination of the ?lm under mechanical bending. Moreover, as each graphene layer restacks, the performance of the ?lm as an electrode for a supercapacitor becomes limited. In this study, facile laser welding and surface modi?cation processes are demonstrated to overcome these limitations. First, a continuous wave laser beam is applied to the interface between the coated graphene and the underlying transparent polycarbonate substrate. This welding process signi?cantly improves their adhesion and enables excellent mechanical bendability. Second, surface modi?cation of graphene is achieved under ambient conditions by irradiating the graphene ?lm surface with a nanosecond pulsed laser. Sandwich-type supercapacitors are fabricated using these surface-modi?ed graphene electrodes with a PVA-H3PO4 electrolyte. The e?ect of the laser ?uence on the performance of the supercapacitor is investigated. At an optimal laser power, an areal capacitance of 4.7 mF/cm2 is achieved.
关键词： Laser transmission welding,Graphene,Flexible device,Supercapacitor,Pulsed laser
更新于2025-11-25 10:30:42
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2D electric-double-layer phototransistor for photoelectronic and spatiotemporal hybrid neuromorphic integration
摘要： The hardware implementation of neuromorphic computing has attracted growing interest as a promising candidate for confronting the bottleneck of traditional von Neumann computers. However, most previous reports are focused on emulating the synaptic behaviors by a mono-mode using an electric-driving or photo-driving approach, resulting in a big challenge to synchronously handle the natural photoelectric information. Herein, we report a multifunctional photoelectronic hybrid-integrated synaptic device based on the electric-double-layer (EDL) MoS2 phototransistor. Interestingly, the electric MoS2 synapse exhibits a potentiation filtering effect, while the photonic counterpart can implement both potentiation and depression filtering effects. Most importantly, for the first time, photoelectronic and spatio-temporal four-dimensional (4D) hybrid integration was successfully demonstrated by the synergic interplay between photonic and electric stimuli within a single MoS2 synapse. An energy band model is proposed to further understand such a photoelectronic and spatio-temporal 4D hybrid coupling mechanism. These results might provide an alternative solution for the size-scaling and intellectualization campaign of the post-Moore era, and for more sophisticated photoelectronic hybrid computing in the emerging neuromorphic nanoelectronics.
关键词： neuromorphic computing,electric-double-layer,synaptic device,MoS2 phototransistor,photoelectronic hybrid integration
更新于2025-11-25 10:30:42
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Fabrication and characterization of lead sulfide (PbS) thin film based heterostructure (FTO/CdS/PbS/Ag) solar cell by nebulizer spray method
摘要： This work deals with the study on the key properties of PbS thin films prepared by simple nebulizer spray method. The structural study done by XRD exhibited cubic crystal structure with polycrystalline nature for the deposited PbS films. The obtained crystallite size was varied between 41 to 55 nm for various molar concentrations. The morphology study done by SEM displays uniform distribution of the grains all over the surface of the prepared PbS thin films. The observed band gap value was decreased from 1.8 eV to 1.51 eV for various molar concentrations. The emitted PL intensity was strong at about 580 nm which is related to the near band edge (NBE) emission. Electrical studies performed by Hall Effect measurement confirm the p-type conductivity of prepared films. Resistivity and carrier concentrations are 2.92×103 Ω-cm and 4.83×1013cm-3 respectively for the deposited films. In addition, a heterojunction solar cell of structure FTO/n-CdS/p-PbS/Ag was produced and its conversion efficiency was ~ 0.39%.
关键词： SEM,PbS,Heterojunction device.,Hall Effect,Photoluminescence
更新于2025-11-21 11:18:25
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A supramolecular Cd( <scp>ii</scp> )-metallogel: an efficient semiconductive electronic device
摘要： A sonication-based strategy for the synthesis of a functional supramolecular Cd(II)-metallogel (CdA-OX) has been achieved through mixing cadmium(II) acetate dihydrate and oxalic acid dihydrate, a low molecular weight gelator (LMWG), in N,N-dimethyl formamide solvent at room temperature under atmospheric pressure. The mechanical properties of the supramolecular Cd(II)-metallogel were investigated through a rheological study. The pebble-like self-assembly hierarchical architecture of the supramolecular metallohydrogel was visualized through field emission scanning electron microscopy investigations. The electrical properties of the metallogel were thoroughly examined and indicate its semiconducting nature. Based on its conducting properties, the Cd(II)-metallogel was successfully applied to a Schottky barrier diode. Overall, this work is a novel instance of technologically challenging electronic device application of a Cd(II)-metallogel.
关键词： Schottky barrier diode,supramolecular Cd(II)-metallogel,sonication-based synthesis,electronic device,semiconducting nature
更新于2025-11-21 11:18:25
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Device simulation of Cu(In,Ga)Se2 solar cells by means of voltage dependent admittance spectroscopy
摘要： The simulation of solar cell devices is important for the understanding of defect physics and loss mechanisms in real solar cells. On the other hand, voltage dependent admittance spectroscopy delivers essential information for establishing a baseline simulation model of Cu(In,Ga)Se2 (CIGSe) solar cells. Here we give an explanation for the weak temperature dependence of the N1-signal, the latter being not compatible with a bulk defect or with a simple hole barrier at the Mo back contact. Furthermore, we find a Ed,IF – EV ≈ 0.3 eV deep recombination-active acceptor state at the absorber/buffer interface made of air-light exposed CIGSe absorbers. This gives us the ability to explain the reduction of power conversion efficiency of solar cells made from air-light exposed absorbers. From the voltage dependent capacitance step of this interface defect we can deduce the formerly unknown position of the Fermi level at the hetero junction in equilibrium which is close to mid-gap. Simulation of dark J-V curves allows a refinement of the parameter of this absorber/buffer interface defect, resulting in a defect density of Nd,IF ≈ 3.5·1011 cm-2 as well as capture cross sections of σn ≈ 4·10-16 cm2 for electrons and σp ≈ 3·10-11 cm2 for holes.
关键词： device simulation,Cu(In,Ga)Se2,admittance spectroscopy,defect physics,solar cells
更新于2025-11-14 17:28:48
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Assessment of Bulk and Interface Quality for Liquid Phase Crystallized Silicon on Glass
摘要： This paper reports on the electrical quality of liquid phase crystallized silicon (LPC-Si) on glass for thin-film solar cell applications. Spatially resolved methods such as light beam induced current (LBIC), microwave photoconductance decay (MWPCD) mapping, and electron backscatter diffraction were used to access the overall material quality, intra-grain quality, surface passivation, and grain boundary (GB) properties. LBIC line scans across GBs were fitted with a model to characterize the recombination behavior of GBs. According to MWPCD measurement, intra-grain bulk carrier lifetimes were estimated to be larger than 4.5 μs for n-type LPC-Si with a doping concentration in the order of 1016 cm?3. Low-angle GBs were found to be strongly recombination active and identified as highly defect-rich regions which spatially extend over a range of 40–60 μm and show a diffusion length of 0.4 μm. Based on absorber quality characterization, the influence of intra-grain quality, heterojunction interface, and GBs/dislocations on the cell performance were separately clarified based on two-dimensional (2-D)-device simulation and a diode model. High back surface recombination velocities of several 105 cm/s are needed to get the best match between simulated and measured open circuit voltage (Voc), indicating back surface passivation problem. The results showed that Voc losses are not only because of poor back surface passivation but also because of crystal defects such as GBs and dislocation.
关键词： Bulk lifetime,heterojunction,grain boundaries (GBs),two-dimensional (2-D)-device simulation,liquid phase crystallized silicon (LPC-Si),light beam induced current (LBIC)
更新于2025-11-14 15:25:21
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Crystalline Semiconductor Boron Quantum Dots
摘要： Zero-dimensional boron structures have always been the focus of theoretical research owing to its abundant phase structures and special properties. Boron clusters have been reported extensively by combining structure searching theories and photoelectron spectroscopy experiments, however, crystalline boron quantum dots (BQDs) have rarely been reported. Here we report the preparation of large-scale and uniform crystalline semiconductor BQDs from the expanded bulk boron powders via a facile and efficient probe ultrasonic approach in acetonitrile solution. The obtained BQDs have 2.46 nm in an average lateral size and 2.81 nm in thickness. Optical measurements demonstrate that strong quantum confinement effect occurs in the BQDs, implying the increase of the bandgap from 1.80 eV for the corresponding bulk to 2.46 eV for the BQDs. By injecting the BQDs into polyvinylpyrrolidone as an active layer, a BQDs-based memory device is fabricated which shows a rewriteable nonvolatile memory effect with a low transition voltage of down to 0.5 V and a high ON/OFF switching ratio of 103 as well as a good stability.
关键词： ultrasound,quantum dots,nonvolatile memory device,quantum confinement effect,boron
更新于2025-11-14 15:23:50
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Photodegradable MEH-PPV in a natural rubber matrix: Toward a biocompatible colorimetric film for real-time light dosimetry
摘要： This paper reports an interesting strategy of incorporating a photodegradable polymeric luminophore, the poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] - OC10C6-PPV (MEH-PPV), in an inert natural rubber (Hevea brasiliensisis) - C5H8 (NR) matrix for monitoring and recording the radiation dose administered to patients under phototherapy, particularly in the treatment for jaundice newborns. A time-trend spectro?uorimetric study has been carried out to characterize the luminescent changes of the MEH-PPV/NR luminophore system upon photodegradation by realistic conditions of phototherapy treatment, and the dependence between color and dose was used to determine the dose-response relationships of this color ?lm dosimeter. Cytotoxicity tests (CHO-K1 cell line) have also been conducted on extracts of the OC10C6-PPV/C5H8 before and after photolysis. The experimental results reported here highlight the potential application of photodegradable polymer/natural rubber as a biocompatible skin-mountable patch to monitor light exposure to improve patient care in phototherapy, photodynamic, lasers and radiation therapies.
关键词： Medical-devices,Dosimeter,Printable device,Photooxidation,Organic device,Semiconducting polymer,Radiation oncology
更新于2025-11-14 15:18:02