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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Characterisation of a Novel InP Photonic Integrated Circuits for Direct Modulation Applications
摘要： In this paper, we present two InP based photonic integrated devices used for direct modulation applications. These devices consist of two lasers which can be used in a master-slave configuration. A detailed study on the interaction between the different sections of the PICs and their impact on the static and dynamic characteristics is given.
关键词： InP photonic integrated device,static characterisation,Fabry-Perot laser
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Quantum Measurement of a Mechanical Resonator at and Below the Standard Quantum Limit
摘要： Interferometric techniques to measure mechanical displacement are subject to constraints ultimately governed by quantum mechanics. In a “standard” measurement of a mechanically induced optical phase shift, there exists a trade-off between measurement imprecision and motion disturbance, known as standard quantum limit (SQL). For a mechanical resonator with susceptibility χm(Ω), this limit is SSQL(Ω) = ˉh|χm(Ω)| (ˉh reduced Planck constant), at any frequency Ω. In the last half-century, a number of systems, including advanced LIGO and ultracold atoms have progressed towards this limit, but excess sources of noise have yet prevented fully reaching the SQL. Here, we show measurements of an ultracoherent mechanical resonator performed at the SQL within 33% and, for the ?rst time, below the SQL by 1.5 dB. The latter has been possible by a non-standard measurement scheme that exploits quantum correlations between optical quadratures induced in the optomechanical device.
关键词： Standard Quantum Limit,Optomechanical Device,Quantum Measurement,Mechanical Resonator
更新于2025-09-11 14:15:04
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Photo-driven water splitting photoelectrochemical cells by tandem organic dye sensitized solar cells with I?/I3? as redox mediator
摘要： Dye-sensitized photoelectrochemical tandem cells have shown the promise for light driven hydrogen production from water owing to the low cost, wide absorption spectra in the visible region and ease to process of their constitutive photoelectrode materials. However, most photo-driven water splitting photoelectrochemical cells driven by organic dye sensitized solar cells exhibit unsatisfactory hydrogen evolution rate, primarily attributed to their poor light capturing ability and low photocurrent performance. Here we present the construction of a tandem system consisting of an organic blue-colored S5 sensitizer-based dye-sensitized photoelectrochemical cell (DSPEC) wired in series with three spectral-complemental dyes BTA-2, APP-3 and APP-1 sensitizers-based dye-sensitized solar cell (DSC), respectively. The two spectral-complemental chromophores were used in DSC and DSPEC to ensure that the full solar spectrum could be absorbed as much as possible. The results showed that the photocurrent of tandem device was closely related to the open-circuit voltage (Voc) of sensitized DSC, in which the tandem configuration consisting of S5 based DSPEC and BTA-2 based DSC gave the best photocurrent. On this basis, tandem device with the only light energy and no external applied electrical bias was further constructed of BTA-2 based 2-junction DSC and S5 based DSPEC and obtained a photocurrent of 500 μA cm?2 for hydrogen generation. Furthermore, I?/I3 ? was used as a redox couple between dye regeneration and O2 production on the surface of Pt-IrO2/WO3. The strategy opens up the application of pure organic dyes in DSC/DSPEC tandem device.
关键词： dye-sensitized photoelectrochemical cells,water splitting,tandem device,dye-sensitized solar cells
更新于2025-09-11 14:15:04
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Ni/4H-SiC interaction and silicide formation under excimer laser annealing for ohmic contact
摘要： Nickel Silicidation reactions were activated on 4H-SiC using laser annealing at wavelength of 308 nm to study interaction and re-action of the involved atomic species. With this intent, the deposited nickel layer thickness was scaled from 100 nm to 10 nm and the laser fluence was spanned from 2.2 to 4.2 J/cm2. A combination of structural characterization by X-ray diffraction, Energy-Dispersive X-ray spectroscopy, Raman Spectroscopy, Transmission Electron Microscopy and morphological investigations through Scanning Electron Microscopy with theoretical predictions as a function of the applied laser fluence, have unveiled that the starting nickel thickness plays a main role, especially above the threshold for nickel melting (2.8J/cm2). As a general paradigm, sufficient silicon release from the substrate occurs above this threshold that is available for silicidation, with amount increasing with the laser fluence. This addresses stoichiometry and morphology of the silicided contact that indeed depend on the available Nickel atoms (i.e. the Ni layer thickness) and on the thermal profile, as tested at a fixed fluence of 3.8J/cm2. In addition, a layer-by-layer variable stoichiometry is established in each sample through the contact, with the deepest silicide being relatively more Si-rich. All those findings have impact on the electrical parameters of testing diodes. Based on data cross-linking, NiSi2 contacting layers and C-free interfaces provide a convenience in reducing resistance contributions.
关键词： simulation,silicon carbide,power device,UV-laser,silicidation reaction,chemical composition
更新于2025-09-11 14:15:04
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Manipulating charge carrier transporting of disubstituted phenylbenzoimidazole-based host materials for efficient full-color PhOLEDs
摘要： Many efforts have been focused on exploring highly efficient host materials that capable of function in phosphorescent organic light-emitting devices (PhOLEDs). However, superior hosts reported to date that are generally suitable to full-color devices are rare and the resultant device performances are far from satisfactory. A class of host compounds DCzPBI, POCzPBI, and DPOPBI, incorporating carbazole and diphenylphosphoryl oxide moieties as electron-donating and -accepting groups, respectively, are synthesized and successfully applied as universal hosts in the fabrication of full-color PhOLEDs. The effect of substituted groups on the photophysical, theoretical calculations, and electrochemical characters for host materials is systematically investigated. We adopt the same device architecture to fabricate the blue, green, yellow, and red PhOLEDs with the combination of the three hosts. As a result, DPOPBI and POCzPBI with good charge carrier transporting properties supported the devices with the impressive efficiencies. The best current efficiency (CE) are 23.2, 48.4, 45.7, 21.5 cd A?1 for blue, green, yellow, and red devices, respectively. Even at the brightnesses of 1000 cd m?2, the efficiency roll-offs are only 2% for green and 0.2% for yellow devices, indicating the promising applications as universal hosts for highly efficient PhOLEDs.
关键词： impressive efficiency,phosphorescent organic light-emitting device,good charge carrier transporting property,host material
更新于2025-09-11 14:15:04
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Near-infrared polymer light-emitting diodes based on an inverted device structure
摘要： Near-infrared polymer light-emitting diodes (NIR-PLEDs) possess great potential in applications ranging from night-vision device to optical communications. Here we obtained NIR emission from normal red fluorescent polymers by using an inverted device structure with the aid of micro-cavity effects. By tuning the thickness of the emissive layer, the inverted NIR-PLED based on PPF-FSO15-DHTBT10 and MEH-PPV got a near-infrared emission with the main peak located at 700 nm and 706 nm, and the maximum external quantum efficiency (EQEmax) of 0.54% and 1.03%, respectively. The increase of emissive layer thickness caused the relative variation of recombination area, which led to the widely controlling of EL spectra in the inverted device. These results reveal that tuning EL spectrum utilized by inverted device structure would be a promising method to realize near-infrared emission.
关键词： emissive layer thickness,micro-cavity effects,inverted device structure,Near-infrared polymer light-emitting diodes,external quantum efficiency
更新于2025-09-11 14:15:04
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Post-functionalization of polyvinylcarbazoles: An open route towards hole transporting materials for perovskite solar cells
摘要： We report on the potential of tuning poly(9-vinylcarbazole) (PVK) properties through functionalization for an application as hole transport material (HTM) for perovskite solar cells (PSCs). The synthesized PVK-based polymers were substituted with moieties of interest to improve the solubility, the charge transport properties, or to tune energy levels. Bis(4-methoxyphenyl)amine moieties were found to improve the hole mobility and to increase the HOMO level of the PVK. Therefore, PSCs employing PVK-[N(PhOCH3)2]2 as HTM exhibited a best PCE of 16.7%. Compared to spiro-OMeTAD, first studies have shown that PVK-[N(PhOCH3)2]2 could extend PSC lifetime.
关键词： Hole mobility,Hole-transporting materials,Device stability,Perovskite solar cells,Polyvinylcarbazoles
更新于2025-09-11 14:15:04
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A Distributed-Parameter Approach for the Surface Temperature Estimation of an LED Heated Silicon Wafer
摘要： A variety of processes in the semiconductor industry require heating of the silicon wafer to the desired temperature. This process is widely referred to as rapid thermal processing. However, the contactless measurement of the surface temperature of the wafer is still a major challenge, especially in the case of rotating wafers. Measurements using infrared cameras are not suitable due to the fact that silicon is transparent in this wavelength range. Special sensors based on the principle of pyrometry are available, but such sensors can only measure the surface temperature at one single point. This paper presents an observer approach that estimates the wafer’s surface temperature by using the temperature measurement of only one pyrometer. The approach is based on a mathematical model capturing the dynamical behavior of the wafer’s temperature. It relies mainly on the quasi-linear heat equation. Real world experiments demonstrate the achieved accuracy of the proposed approach.
关键词： Rapid thermal processing,semiconductor device manufacture,distributed parameter systems,process control
更新于2025-09-11 14:15:04
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Mission Profile-Oriented Control for Reliability and Lifetime of Photovoltaic Inverters
摘要： With the aim to increase the competitiveness of solar energy, the high reliability of Photovoltaic (PV) inverters is demanded. In PV applications, the inverter reliability and lifetime are strongly affected by the operating condition that is referred to as the mission profile (i.e., solar irradiance and ambient temperature). Since the mission profile of PV systems is location-dependent, the inverter reliability performance and lifetime can vary considerably in practice. That is, from the reliability perspective, PV inverters with the same design metrics (e.g., component selection) may become over- or under-designed under different mission profiles. This will increase the overall system cost, e.g., initial cost for over-designed cases and maintenance cost for under-designed cases, which should be avoided. This paper thus explores the possibility to adapt the control strategies of PV inverters to the corresponding mission profiles. With this, similar reliability targets (e.g., component lifetime) can be achieved even under different mission profiles. Case studies have been carried out on PV systems installed in Denmark and Arizona, where the lifetime and the energy yield are evaluated. The results reveal that the inverter reliability can be improved by selecting a proper control strategy according to the mission profile.
关键词： capacitor,reliability,lifetime,PV inverters,mission profile,power device,control
更新于2025-09-11 14:15:04
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Facile synthesis of the desired red phosphor Li <sub/>2</sub> Ca <sub/>2</sub> Mg <sub/>2</sub> Si <sub/>2</sub> N <sub/>6</sub> :Eu <sup>2+</sup> for high CRI white LEDs and plant growth LED device
摘要： The red emission with suitable peak wavelength and narrow band is acutely required for high color rendering index (CRI) white LEDs without at the cost of the luminous efficacy. Herein, the Li2Ca2Mg2Si2N6:Eu2+ red phosphor was prepared with facile solid-state method using Ca3N2, Mg3N2, Si3N4, Li3N, and Eu2O3 as the safety raw materials under atmospheric pressure for the first time, which shows red emission peaking at 638 nm with full width at half maximum (FWHM) of 62 nm under blue light irradiation and becomes the desired red phosphor to realize the balance between luminous efficacy and high CRI in white LEDs. The morphology, structure, luminescence properties, thermal quenching behavior, and chromaticity stability of the Li2Ca2Mg2Si2N6:Eu2+ phosphor are investigated in detail. Concentration quenching occurs when the Eu2+ content exceeds 1.0 mol%, whereas high temperature photoluminescent measurements show a 32% drop from the room temperature efficiency at 423 K. In view of the excellent luminescence performances of Li2Ca2Mg2Si2N6:Eu2+ phosphor, a white LEDs with CRI of 91 as a proof-of-concept experiment was fabricated by coating the title phosphor with Y3Al5O12:Ce3+ on a blue LED chip. In addition, the potential application of the title phosphor in plant growth LED device was also demonstrated. All the results indicate that Li2Ca2Mg2Si2N6:Eu2+ is a promising red-emitting phosphor for blue-LED-based high CRI white LEDs and plant growth lighting sources.
关键词： Li2Ca2Mg2Si2N6:Eu2+,high CRI white LEDs,plant growth LED device,phosphor
更新于2025-09-11 14:15:04