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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • medical application
  • electrical capacitance tomography
  • electrical impedance tomography
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • University of Manchester
  • Chiba University
123 条数据
?? 中文（中国） ▾

  • Stable perovskite based photodetector in impedance and capacitance mode

    摘要： Nowadays perovskite emerges as a promising photosensitive material for next-generation solution-processed devices. Perovskite-based solar cells degrade in ambient conditions up to some extent, after which they are discarded. In our work, we are using reusing the degraded cells as a high-performance stable perovskite-based photodetector. The symmetry of the detector is FTO/PEDOT:PSS/Perovskite/PC61BM/CdS/Ag showing sensitivity to light with respect to (w.r.t) impedance and capacitance. To enhance the excitons generation and absorption of light, the electron transport layer of cadmium sulfide along with PC61BM is selected and PEDOT:PSS layer is used for hole transportation. Atomic force microscopy, X-ray diffraction, and UV-absorption spectrum were obtained to study the surface morphology, composition, and absorption of the perovskite layer. The electric parameters within the frequency range 100 Hz to 200 kHz of samples under the effect of light were investigated. Experimental results showed that with the change in light intensity from dark to 325 W/m2, the highest impedance and capacitance were observed at 100 Hz. The impedance sensitivity is -126.154 kΩ m2/W and the uppermost capacitance sensitivity w.r.t light intensity is 6.77 pF m2/W. Frequency-impedance and capacitance relationships and sensitivities were also measured. The results showed that in the range from 100 Hz to 200 kHz the maximum impedance sensitivity is -343.37 Ω/Hz in dark condition. While the capacitance sensitivity was highest when light intensity was 325 W/m2 (-37.27 pF/kHz), respectively. We attribute these observations due to the generation of electron-hole pairs under light and by the increase of their concentration, by the presence of the built-in capacitance and possible frequency dependence of the mobility of the charges.

    关键词： capacitance mode,frequency,photodetector,hybrid organic-inorganic,impedance mode,Perovskite

    更新于2025-09-16 10:30:52

  • Capacitive Characteristics of High-Speed Photovoltaic Converters at Combined Lighting

    摘要： p–i–n GaAs photovoltaic converters of modulated laser radiation (810–830 nm) transferring both energy (laser power) and information signal were developed. The capacitance and frequency characteristics of the photovoltaic converters at a constant 0.2–1 W and variable 16 mW laser power were studied. The dependences of the heterostructures capacitance on the voltage at the p–i–n junction were obtained; it has been found out that the charge accumulated in the i-layer plays the dominant role. As a result, the decrease in the thickness of the undoped region improves the frequency characteristics. This paper shows that at the voltage in the DC circuit of 0.8 V and the laser power of 0.6 W, the efficiency of 39% can be achieved with the 450 MHz transmission band in case of the 20 mV AC signal amplitude at the load of 2.5 Ω. For the voltage in the DC circuit of 1 V in similar modes of continuous laser radiation, the efficiency was 48.6%, and the transmission band was 135 MHz. Increasing the laser power to 1 W reduced the efficiency by about 1% and the bandwidth by 30 MHz. The achieved characteristics of the studied photovoltaic converters would make it possible to use them for providing autonomous power supply for devices with low power consumption at the data rate of 100 Mbit/s and above.

    关键词： modulated laser radiation,capacitance,p–i–n structure,photovoltaic converters

    更新于2025-09-16 10:30:52

  • Through Concentration Profiling of Heterojunction Solar Cells

    摘要： Electrochemical capacitance–voltage profiling has been used to examine heterojunction solar cells based on single-crystal silicon. Specific features of the electrochemical capacitance–voltage profiling of modern multilayer heterojunction solar cells have been analyzed. The distribution profiles of majority carriers across the whole thickness of the samples were obtained, including, for the first time, those in layers of conducting indium tin oxide.

    关键词： electrochemical capacitance–voltage profiling,single-crystal silicon,amorphous silicon,heterojunction solar cells

    更新于2025-09-16 10:30:52

  • [IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Optical-Response Analysis of Voltage-Modulated 1.3 μm Wavelength AlGaInAs/InP Transistor Laser

    摘要： Transistor Laser (TL) has multiple modulation methods by a combination of terminal connection because it has three electrical terminals unlike the laser diodes. In this report, for the voltage modulation of the TL, the light output response under a large signal voltage modulation was simulated. By considering the transient change of the current in the active layer, we succeeded in reproducing the light output having the peak in the opposite direction to the steady state observed with the actual device so far. Based on the simulation, the optimum collector-base capacitance in the actual device and the minimum required end-facet reflectance for securing a high extinction ratio were obtained.

    关键词： light output response,voltage modulation,collector-base capacitance,Transistor Laser,end-facet reflectance

    更新于2025-09-16 10:30:52

  • [IEEE 2019 26th IEEE International Conference on Electronics, Circuits and Systems (ICECS) - Genoa, Italy (2019.11.27-2019.11.29)] 2019 26th IEEE International Conference on Electronics, Circuits and Systems (ICECS) - Exploiting Negative Impedance Converters to Extend the Bandwidth of LEDs for Visible Light Communication

    摘要： This paper proposes, for the ?rst time, an optically lossless light emitting diode (LED) bandwidth extension technique based on the adoption of negative impedance converters applied in the context of high capacity visible light communication systems. The proposed technique aims to achieve bandwidth extension by offsetting the bandwidth-limiting effect of the LED diffusion capacitance through the introduction of a parallel negative capacitance. With the proposed technique, we predict up to 200% improvement in the LED modulation bandwidth with studies based on a veri?ed LED equivalent model.

    关键词： negative impedance converters,Light emitting diodes,visible light communication,negative capacitance

    更新于2025-09-16 10:30:52

  • Fabricating Strongly Coupled V2O5@PEDOT Nanobelts/Graphene Hybrid Films with High Areal Capacitance and Facile Transferability for Transparent Solid-State Supercapacitors

    摘要： Transparent energy-storage devices are of enormous significance to the continued growth of flexible and wearable electronics in the foreseeable future. The development of transparent supercapacitive electrodes that possess not only high optical transmittance but also intriguing features of energy-storage capability, transferability and outstanding durability, remains a remarkable challenge. Here we demonstrate a polymer-glued strategy to fabricate the conjugated transparent hybrids of V2O5 and graphene, whereby the poly(3,4-ethylenedioxythiophene) (PEDOT) forms a conformal coating on the surface of V2O5 nanobelts and functions as a glue. Interestingly, the PEDOT-glued V2O5/graphene (VP-G) is easy-transferrable onto various flat and even curved substrates. When served as a transparent supercapacitive electrode, the VP-G exhibits a high areal capacitance of 22.4 mF cm?2 at an optical transparency of 70%. As unveiled by experimental results and density functional theory (DFT) calculations, both the kinetic blocking of the PEDOT layer and the anchoring capability of graphene upon soluble vanadium ions contribute synergistically to the unusual electrochemical stability. Transparent, high-energy-density solid-state supercapacitors made of the as-fabricated hybrids are constructed, exhibiting a high energy density of 0.18 μWh cm?2 at 11 μW cm?2. As expected, the constructed transparent supercapacitors demonstrate an excellent cycling stability over 50 000 cycles with capacitance retention of 92.4%. These results show its great potential as promising transparent devices.

    关键词： transparent supercapacitors,high stability,high areal capacitance,strongly coupled nanocompsites,transferable electrode

    更新于2025-09-16 10:30:52

  • Liquid crystal-based capacitive, electro-optical and dielectric biosensors for protein quantitation

    摘要： The electrical, electro-optical and dielectric properties of liquid crystals (LCs) are routinely manipulated in liquid-crystal display (LCD) devices, but their potential application in the development of biosensors is still in a nascent stage. In this review, utilising the electrical properties, electro-optical effect and dielectric anisotropy in LCs, we provide insights into several possible modes of label-free biodetection and describe how capacitance, electro-optical and dielectric measurements of various LCs assist in quantitative analysis of biomolecules. It is concluded that the electrically induced biosensing techniques proposed here provides new incentives for researchers to study the interaction between LCs and biomolecules and to resolve technical hurdles facing the development of LC-based biosensors.

    关键词： bovine serum albumin,biosensing,dielectric spectroscopy,Electro-optical measurement,protein,capacitance

    更新于2025-09-16 10:30:52

  • Ion Transport in Laser-Induced Graphene Cation-Exchange Membrane Hybrids

    摘要： Ion exchange membranes hybridized with laser-induced graphene (LIG) might lead to membranes with functional surface effects such as antifouling, antibacterial or joule heating, however, understanding the change in the electrical properties of the membrane is essential. Here we studied LIG-modified ion-exchange polymeric membranes using electrochemical impedance spectroscopy (EIS). The conductivity of the anionic sulfonated polyethersulfone membranes and the effective capacitance of the membrane-electrolyte interface were obtained by fitting the EIS spectra to an electrochemical equivalent circuit and compared to LIG-modified non-ionic polyethersulfone films. The transport selectivity (as relative permeability) of counter-ions (K+, Na+, Mg2+, Ca2+) across the membrane was quantified using the membrane’s conductivities obtained from the EIS measurements. The total ohmic resistance of the membrane was directly correlated to the polymer thickness, (with negligible contribution from the conductive LIG layer), thereby establishing EIS as a rapid, low-cost and non-invasive method to accurately probe substrate usage in LIG modification.

    关键词： laser-induced graphene,electrochemical impedance spectroscopy,capacitance,ion exchange membranes,conductivity,ion transport

    更新于2025-09-16 10:30:52

  • Wavelength and Constant Magnetic field Dependence of the Steady-state Photoconductivity of a Bifacial Silicon Solar Cell

    摘要： In this work, a theoretical study on the photoconductivity of a bifacial silicon solar cell under monochromatic illumination and constant magnetic field is presented. Analytical expression of the photoconductivity is established according to base depth, illumination wavelength, junction recombination velocity and magnetic field value. The photoconductivity profile versus wavelength shows two energy absorption peaks corresponding to specific wavelengths. Based on a linear model of the photoconductivity versus junction recombination velocity, in a given interval, we determine an equivalent capacitance which depends on both wavelength and magnetic field.

    关键词： Capacitance,Recombination velocity,Wavelength,Photoconductivity,Magnetic field

    更新于2025-09-16 10:30:52

  • Pedestal substrate integrated waveguide filter with both electric and magnetic cross-couplings

    摘要： In single-phase photovoltaic (PV) system, there is double-frequency power mismatch existed between the dc input and ac output. The double-frequency ripple (DFR) energy needs to be buffered by passive network. Otherwise, the ripple energy will flow into the input side and adversely affect the PV energy harvest. In a conventional PV system, electrolytic capacitors are usually used for this purpose due to their high capacitance. However, electrolytic capacitors are considered to be one of the most failure prone components in a PV inverter. In this paper, a capacitance reduction control strategy is proposed to buffer the DFR energy in single-phase Z-source/quasi-Z-source inverter applications. Without using any extra hardware components, the proposed control strategy can significantly reduce the capacitance requirement and achieve low input voltage DFR. Consequently, highly reliable film capacitors can be used. The increased switching device voltage stress and power loss due to the proposed control strategy will also be discussed. A 1-kW quasi-Z-source PV inverter using gallium nitride (GaN) devices is built in the lab. Experimental results are provided to verify the effectiveness of the proposed method.

    关键词： Capacitance reduction,double-frequency ripple (DFR),Z-source (ZS)/quasi-Z-source (qZS)

    更新于2025-09-16 10:30:52