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MV Power Conversion Systems Enabled by High-Voltage SiC Devices [Happenings]
摘要： The current electrical distribution system needs to adapt due to an increase in demand and requirements for a “smarter grid,” which are required because of the proliferation of distributed energy resources (DERs). Transformers form an integral part of these electrical grids, and an upgrade to handle the additional requirements that come along is imperative. Unfortunately, an upgrade in a conventional sense is not possible, so it is time to think beyond conventional transformers. Thanks to recent strides in power electronics research and the availability of high-voltage (HV) silicon carbide (SiC) power semiconductor devices, we can contemplate building a smart “solid-state transformer” to handle the demands of the smart grid. In electrical distribution systems, the transformers convert thousands of volts [medium voltage (MV)] into lower voltages that can be safely used in homes and businesses [1]. With emerging technologies in building and fabricating MV SiC-based power semiconductor devices, MV power conversion on a large-scale scenario seems feasible. While companies, such as Wolfspeed (CREE), General Electric, Infineon Technologies, Mitsubishi, and ROHM, continue to develop and improve these MV semiconductor devices, we at the FREEDM Systems Center are aiming at the application side of things to ensure a market for these power devices.
关键词： SiC devices,smart grid,solid-state transformer,MV power conversion,power conversion
更新于2025-09-16 10:30:52
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Physical properties of quasi-solid-state polymer electrolytes for dye-sensitised solar cells: A characterisation review
摘要： The electrolyte is a critical component of dye-sensitised solar cells (DSSCs). Among them, quasi-solid state (QSS) electrolytes are considered as one of the most prospective substitutes for liquid electrolytes to DSSCs. To entirely understand and optimise the performance and stability of QSS, comprehensive characterisation is needed to design new materials, comprehend and optimise the QSS. This review summarises the characterisations of QSS beginning from 2010. Emphasis is placed on the physical characterisations such as viscosity, morphology, thermal, infrared spectroscopy, nuclear magnetic resonance, Raman, ultraviolet-visible, and X-ray di?raction. All parts of the characterisation process are divided into the introduction, the objective of testing, main outcomes and ?nally, the selected examples. A summary of recent and important measurements on QSS are mentioned at the end.
关键词： Quasi-solid state electrolytes,Characterisations,Gel polymer electrolytes,Dye-sensitised solar cells,Polymer electrolytes
更新于2025-09-16 10:30:52
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Atomic-Level Microstructure of Efficient Formamidinium-Based Perovskite Solar Cells Stabilized by 5-Ammonium Valeric Acid Iodide Revealed by Multi-Nuclear and Two-Dimensional Solid-State NMR
摘要： Chemical doping of inorganic-organic hybrid perovskites is an effective way of improving the performance and operational stability of perovskite solar cells (PSCs). Here we use 5-ammonium valeric acid iodide (AVAI) to chemically stabilize the structure of α-FAPbI3. Using solid-state MAS NMR, we demonstrate the atomic-level interaction between the molecular modulator and the perovskite lattice and propose a structural model of the stabilized three-dimensional structure, further aided by density functional theory (DFT) calculations. We find that one-step deposition of the perovskite in the presence of AVAI produces highly crystalline films with large, micrometer-sized grains and enhanced charge-carrier lifetimes, as probed by transient absorption spectroscopy. As a result, we achieve greatly enhanced solar cell performance for the optimized AVA-based devices with a maximum power conversion efficiency (PCE) of 18.94%. The devices retain 90% of the initial efficiency after 300 h under continuous white light illumination and maximum-power point-tracking measurement.
关键词： power conversion efficiency,density functional theory,perovskite solar cells,chemical doping,solid-state MAS NMR,charge-carrier lifetimes,5-ammonium valeric acid iodide
更新于2025-09-16 10:30:52
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Analysis and numerical design of Resistive AC-Coupled Silicon Detectors (RSD) for 4D particle tracking
摘要： In this paper we present the numerical simulation of silicon detectors with internal gain as the main tool for 4-dimensional (4D) particle trackers design and optimization. The Low-Gain Avalanche Diode (LGAD) technology and its present limitations are reviewed with the aim of introducing the Resistive AC-Coupled Silicon Detectors (RSD) paradigm as a case study of our investigation. Authors here present Spice-like and 2D/3D Technological Computer-Aided Design (TCAD) simulations to characterize sensors in terms of both their electrostatic behavior, capacitive (dynamic) coupling and radiation-hardness performances, showing the methodological approach used in order to extract the set of layout rules allowing the release of RSD1, the incoming production run at Fondazione Bruno Kessler (FBK) of next-generation silicon detectors for 4D tracking with intrinsic 100% fill-factor.
关键词： Charge multiplication,Fast detectors,Solid-state silicon detectors,TCAD modeling,Particle tracking detectors,Particle timing detectors
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Daejeon, Korea (South) (2019.7.28-2019.8.1)] 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Ultra-Broadband and Polarization-Insensitive Tunable Metasurface Absorber
摘要： This paper presents the implementation of an automated roll-to-roll ?uidic self-assembly system based on the surface tension driven self-assembly with applications in the ?eld of macroelectronics. The reported system incorporates automated agitation, web motion, component dispensing, and recycling. The process enables the assembly and electrical connection of semiconductor dies/chips in a continuous and parallel method achieves an assembly rate of 15 000 chips per hour and an assembly yield exceeding 99%, testing assembly of standard square-shaped dies, 300–1000 μm size. Scaling the system to any desired throughput is possible due to the parallel manner of self-assembly. The identi?cation and the modeling of the relationship between process parameters and forces have been studied and experimentally veri?ed by testing the effect of the web angle, agitation on assembly, and detachment rates. As an application, we demonstrate the realization of a solid-state lighting module. This particular application requires the assembly of a conductive multilayer sandwich structure, which is achieved by combining the introduced assembly process with a novel lamination step.
关键词： solid state lighting,Roll-to-roll,fluidic self-assembly,flexible electronics
更新于2025-09-16 10:30:52
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Characteristics of an organic photodetector with a conjugated donor and non-fullerene acceptor for indirect X-ray detection
摘要： In this study, an organic photodetector with a small band-gap donor, PBDB-T, and a non-fullerene acceptor, ITIC, was investigated as the active element in an indirect imaging system using a scintillator of the detector for indirect X-ray imaging. Compared with the common organic photodetector with a P3HT:PC70BM active layer, higher conversion e?ciencies can be expected, because the proposed detector is advantageous for visible-light absorption and carrier transport. The absorption peak of the PBDB-T:ITIC layer was located at 640 nm and was not well-matched with the emission properties of a CsI(Tl) scintillator. Therefore, a ZnSe(Te) scintillator with an emission peak at 620 nm was also tested. Compared with the P3HT:PC70BM detector, the ZnSe(Te)-coupled detector with the PBDB-T:ITIC = 1:1 active layer was 191% higher in collected current density (CCD) and 205% higher in sensitivity. The frequency response was measured with a 520 nm green LED. The detector with the PBDB-T:ITIC layer showed the -3 dB cut-o? frequency of 31.5 kHz, which was higher than the cut-o? frequency of the P3HT:PC70BM detector.
关键词： Materials for solid-state detectors,Photon detectors for UV, visible and IR photons (solid-state) (PIN diodes, APDs, Si-PMTs, G-APDs, CCDs, EBCCDs, EMCCDs, CMOS imagers, etc),X-ray detectors
更新于2025-09-12 10:27:22
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Electrochemiluminescence solid-state imprinted sensor based on graphene/CdTe@ZnS quantum dots as luminescent probes for low-cost ultrasensing of diethylstilbestrol
摘要： A novel molecularly imprinted electrochemiluminescence (MIP-ECL) sensor was fabricated for diethylstilbestrol (DES), which exploited the strategy of specific identification by molecularly imprinted polymers (MIPs) instead of expensive biomolecules. Core-shell quantum-dots (QDs) of CdTe@ZnS were utilized to enhance ECL emission. The sensor was assembled as a solid-state electrode by immobilizing CdTe@ZnS/reduced-graphene oxide (r-GO) composite on a glassy carbon electrode (GCE) surface, and then being covered with MIPs film with specific cavities. The fabricated sensor (denoted as MIP/CdTe@ZnS/r-GO/GCE) was based on the obstruction of ECL signals by DES molecules enriched on MIP film. The ECL intensity of the QDs-K2S2O8 system was reduced when the DES molecules were selectively rebound onto the MIP film by molecularly imprinted solid phase extraction (MISPE). Accordingly, the logarithm of the quenched ECL intensity versus the logarithm of the DES concentration was in a good linear relationship over a wide range from 1.8×10?3 to 25.0 nmol/L with the limit of detection (LOD) of 0.25 pmol/L (S/N = 3). The sensor also exhibits excellent selectivity with fast response and good accuracy. Lake water and milk samples were assayed by this sensor, and the recoveries ranging from 92.2% to 108.3% were obtained.
关键词： Solid-state electrode,Molecularly imprinted film,Diethylstilbestrol,CdTe@ZnS quantum-dots,Electrochemiluminescence sensor,Solid phase extraction
更新于2025-09-12 10:27:22
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Fabrication and performance of AC-coupled LGADs
摘要： Detectors that can simultaneously provide ?ne time and spatial resolution have attracted wide-spread interest for applications in several ?elds such as high-energy and nuclear physics as well as in low-energy electron detection, photon science, photonics and imaging. Low-Gain Avalanche Diodes (LGADs), being fabricated on thin silicon substrates and featuring a charge gain of up to 100, exhibit excellent timing performance. Since pads much larger than the substrate thickness are necessary to achieve a spatially uniform multiplication, a ?ne pad pixelation is di?cult. To overcome this limitation, the AC-coupled LGAD approach was introduced. In this type of device, metal electrodes are placed over an insulator at a ?ne pitch, and signals are capacitively induced on these electrodes. At Brookhaven National Laboratory, we have designed and fabricated prototypes of AC-coupled LGAD sensors. The performance of small test structures with di?erent particle beams from radioactive sources are shown.
关键词： Charge transport and multiplication in solid media,Detector modelling and simulations II (electric ?elds, charge transport, multiplication and induction, pulse formation, electron emission, etc),Solid state detectors,Timing detectors
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE Industry Applications Society Annual Meeting - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Industry Applications Society Annual Meeting - Evaluation of Bit Error Ratio in Differential Phase-Shift-Keying Modulation Applied to VLC LED Drivers
摘要： This work presents a binary differential phase-shift keying (DPSK) modulation technique for visible light communication (VLC) systems aimed at low to moderate data rate applications. VLC uses the modulated light of LEDs to transmit data wireless. Such feature is added into artificial lighting systems by controlling the light intensity of a source. However, in most cases, modulation capabilities for VLC are employed with the addition of extra power components, which may harm efficiency and cost standards. Therefore, single switch LED drivers are preferable to provide VLC along with average current regulation. They are standard low-cost solutions that are able to perform both functions providing a satisfactory efficiency. Hence, in this work, DPSK modulation is applied to a buck converter operating in continuous conduction mode at 250 kHz, providing a raw data rate of 125 kbps. DPSK is advantageous because it overcomes possible parameters changes at the converter, along with possible duty cycle changes given by the control system of the average current for lighting. Moreover, the system performance is evaluated by means of its bit error ratio (BER) over signal-to-noise ratio (SNR), in a line-of-sight setup with variable distances between transmitter and receiver, showing a good behaviour of a BER less than 10?3 for about 8.1 m in a 8.4 W LED load.
关键词： Switched Converter,Solid-State Lighting,Light Emitting Diode,Visible Light Communication
更新于2025-09-12 10:27:22
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Transition metal ion Co-Doped MgO–MgF2-GeO2:Mn4+ red phosphors for white LEDs with wider color reproduction gamut
摘要： Mn4+-activated non-rare-earth based red phosphors are excellent down conversion materials for phosphor-converted light-emitting diode (pc-LEDs) based solid-state lighting applications. However, the low quantum efficiency of Mn4+ activated red phosphors under InGaN based blue LED excitation hinders their use in phosphor-converted LEDs. To enhance the absorption at an excitation wavelength of around 420 nm in Mn4+-doped MgO-MgF2-GeO2 (MGF: Mn4+), which is a conventional red-emitting lamp phosphor, we doped MGF: Mn4+ phosphors with transition metal oxides (Sc2O3, Lu2O3, Y2O3, and La2O3) replacing MgO. When excited using 420 nm light, the absorption ratio of the synthesized phosphors with Sc2O3 (Sc-MGF:Mn4+) was 58% with an internal quantum efficiency (IQE) of 55% as compared to the 35% IQE of the pristine MGF-Mn4+ phosphor. White LEDs were fabricated using Sc-MGF-Mn4+ (red), and β-SiAlON:Eu2+ (green) on InGaN chips (λem = 450 nm) and their performance was compared to the optical performance of LEDs fabricated using K2SiF6:Mn4+ as the red phosphor. According to the National Television System Committee (NTSC) standard, the color reproduction coverage with an Sc-MGF:Mn4+ phosphor-loaded white LED was 121% by the International Commission on Illumination (CIE) 1976, and 80% by the BT.2020 standard. The coverages are 9% and 6% higher than the coverages of LEDs fabricated using K2SiF6:Mn4+ as the red phosphor according to the NTSC and BT.2020 standards, respectively. Our simple approach to enhance the IQE of Mn4+ activated phosphors by co-doping transition metal oxides can be extended to other Mn4+ activated phosphor systems for applications that require enhanced absorption, higher luminescent emission intensity, and a wider gamut of color reproduction.
关键词： MgO-MgF2-GeO2,Mn4+ activated red phosphors,Solid-state lighting,White LEDs,BT.2020
更新于2025-09-12 10:27:22