40 results on '"luminescent devices"'
Search Results
2. Design criteria for micro-optical tandem luminescent solar concentrators
- Author
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Needell, DR, Ilic, O, Bukowsky, CR, Nett, Z, Xu, L, He, J, Bauser, H, Lee, BG, Geisz, JF, Nuzzo, RG, Alivisatos, AP, and Atwater, HA
- Subjects
III-V concentrator photovoltaics ,luminescent devices ,Monte Carlo methods ,quantum dots ,tandem PV ,Quantum Physics ,Electrical and Electronic Engineering ,Materials Engineering - Abstract
Luminescent solar concentrators (LSCs) harness light generated by luminophores embedded in a light-trapping waveguide to concentrate onto smaller cells. LSCs can absorb both direct and diffuse sunlight, and thus can operate as flat plate receivers at a fixed tilt and with a conventional module form factor. However, current LSCs experience significant power loss through parasitic luminophore absorption and incomplete light trapping by the optical waveguide. Here, we introduce a tandem LSC device architecture that overcomes both of these limitations, consisting of a poly(lauryl methacrylate) polymer layer with embedded cadmium selenide core, cadmium sulfide shell (CdSe/CdS) quantum dot (QD) luminophores and an InGaP microcell array, which serves as high bandgap absorbers on the top of a conventional Si photovoltaic. We investigate the design space for a tandem LSC, using experimentally measured performance parameters for key components, including the InGaP microcell array, CdSe/CdS QDs, and spectrally selective waveguide filters. Using a Monte Carlo ray-tracing model, we compute the power conversion efficiency for a tandem LSC module with these components to be 29.4% under partially diffuse illumination conditions. These results indicate that a tandem LSC-on-Si architecture could significantly improve upon the efficiency of a conventional Si photovoltaic cell.
- Published
- 2018
3. En Route to Wide Area Emitting Organic Light‐Emitting Transistors for Intrinsic Drive‐Integrated Display Applications: A Comprehensive Review.
- Author
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Ganesan, Paramaguru, Tsao, Hoi Nok, and Gao, Peng
- Subjects
- *
TRANSISTORS , *DIELECTRIC materials , *ARCHITECTURAL engineering , *FLAT panel displays , *DIELECTRIC devices , *ORGANIC field-effect transistors , *METAL oxide semiconductor field-effect transistors - Abstract
Organic light‐emitting transistors (OLET) evolved from the fusion of the switching functionality of field‐effect transistors (FET) with the light‐emitting characteristics of organic light‐emitting diode (OLED) that can simplify the active‐matrix pixel device architecture and hence offer a promising pathway for future flat panel and flexible display technology. This review systematically analyzes the key device/molecular engineering tactics that assist in improving the electrode edge narrow emission to wide‐area emission for display applications via three different topics, that is, narrow to wide‐area emission, vertical architecture, and impact of high‐κ dielectric on the device performance. Source–drain electrode engineering such as symmetric/asymmetric, planar/non‐planar arrangement, semitransparent nature, multilayer approach comprising charge transport, and work function modification layers enable widening the emission zone. Vertical OLET architecture offers short channel lengths with a high aperture ratio, pixel type area emission, and stable light‐emitting area. Transistors utilizing high‐κ dielectric materials have assisted in lowering the operating voltage, enhancing luminance and air stability. The promising development in achieving wide‐area emission provides a solid basis for constructing OLET research toward display applications; however, it relies on developing highly luminescent and fast charge transporting materials, suitable semitransparent source/drain electrodes, high‐κ ‐dielectrics, and device architectural engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
4. Signal Amplification of Fiber Integrated X-Ray Detector and Energy Independence.
- Author
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Debnath, Sree Bash Chandra, Darreon, Julien, Tallet, Agnes, Goncalves, Anthony, Tonneau, Didier, and Fauquet, Carole
- Abstract
We developed a high spatial resolution and sensitive detector particularly suitable for radiation dose measurements in radiotherapy at small fields and X-ray imaging applications. The detector is based on a silica optical fiber whose sensitive terminal is functionalized by grafting Ag-doped ZnS scintillating materials that emit blue luminescence under X-ray irradiation. Due to the small scintillating head of the detector, the acquisition signal is quite low, and it is measured by a sensitive photon counter plugged at the other terminal of the fiber. The weaker signal can be enhanced significantly by adding a metal coating over the scintillator. Therefore, this study presents the effect of metal thickness and density on the signal amplification at high irradiation energies of 6 MeV and 15 MeV using a Linear Accelerator (LINAC). In addition, the stem effect was characterized for regular to small field beam size and shows that the detector is almost free from stem contribution during high energy irradiation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. A Flip‐Over Plasmonic Structure for Photoluminescence Enhancement of Encapsulated WS2 Monolayers.
- Author
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Liang, Minpeng, Han, Chunrui, Zheliuk, Oleksandr, Chen, Qihong, Wan, Puhua, Peng, Xiaoli, Zhang, Le, and Ye, Jianting
- Subjects
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PHOTOLUMINESCENCE , *MONOMOLECULAR films , *BORON nitride , *TRANSITION metals , *BAND gaps , *OPTOELECTRONICS - Abstract
Transition metal dichalcogenide (TMD) monolayers, with their direct band gaps, have attracted wide attention from the fields of photonics and optoelectronics. However, monolayer semiconducting TMDs generally suffer from low excitation absorption and emission efficiency, limiting their further applications. Here a flip‐over plasmonic structure comprised of silver nano‐disk arrays supporting a WS2 monolayer sandwiched by hexagonal boron nitride (h‐BN) layers is demonstrated. The flip‐over configuration optimizes the optical process with a free excitation/emission path from the top and a strong plasmonic interaction from the bottom. As a result, the photoluminescence from the TMD monolayers can be greatly enhanced more than tenfold by optimizing the metasurface, which can be further improved nearly tenfold by optimizing the thickness of bottom h‐BN. This study shows the advantages of using the flip‐over structure, where the plasmonic interaction between the metasurface and TMDs can be tuned by introducing optimized plasmonic arrays and h‐BN layers with suitable thickness. This hybrid device configuration paves a reliable platform to study the light–matter interaction, achieving highly efficient plasmonic TMD devices. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
6. Colour-tunable and warm white light emitting thermally stable Dy3+/Sm3+ co-activated tungstate-tellurite glasses for photonic applications.
- Author
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Sangwan, Vikas, Jayasimhadri, M., and Haranath, D.
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TELLURITES , *GLASS , *ABSORPTION spectra , *COLOR temperature , *ENERGY transfer , *ACTIVATION energy , *DELAYED fluorescence - Abstract
Transparent single Dy3+, Sm3+, and Dy3+/Sm3+ co-activated tungstate-tellurite (TWKZBi) glass matrices were synthesized via melt-quenching process. The optical features of the prepared glass matrices were examined with the aid of the absorption spectra. Under various excitation wavelengths (366, 388 and 454 nm), Dy3+ doped TWKZBi (TWKZBiDy) glasses revealed a prevailing emission peak ⁓575 nm related to the yellow band (4F 9/2 → 6H 13/2) transition, while Sm3+ doped TWKZBi (TWKZBiSm) glass matrices reveal strong intense emission peak at ∼600 nm associated with the orange-red band (4G 5/2 → 6H 7/2) transition. The emission intensity progressively surges with an increment in Sm3+ ion content (up to 1.5 mol%), confirming the ET mechanism between Dy3+ and Sm3+ ions. Application of Dexter's ET formulation with the Reisfeld's approximation revealed that the ET mechanism involves a non-radiative dipole-dipole (d-d) interaction between Dy3+ and Sm3+ ions. The average lifetime (τ a v g) values for the 4F 9/2 state of Dy3+ ions in the TWKZBiDySm glass sample was measured and found that these values decreased with increasing Sm3+ ion content. In addition, the ET efficiencies (η D y → S m) of the TWKZBiDySm glass matrices were evaluated using the lifetime curves. The color coordinates (x , y) and the correlated color temperature (CCT) values of the co-activated glass samples were estimated. Based on the chromaticity coordinates and CCT values, it was found that the desired color of the TWKZBiDySm glass samples can be modulated from warm white light to orange-red light via precisely adjusting the concentration of Sm3+ ions and at selected excitation wavelengths. Furthermore, the emission intensity observed at 373 K was 83.83 % compared to the emission intensity at ambient temperature, indicating the excellent thermal stability of the TWKZBiDySm glasses prepared. The above results confirm that the prepared Dy3+/Sm3+ co-activated TWKZBi glass matrix can be a promising candidate for white light and other photonic devices. Transparent single Dy3+, Sm3+, and Dy3+/Sm3+ co-activated tungstate-tellurite (TWKZBi) glass matrices were synthesized via the melt-quenching process. The PL spectra were studied at selected excitation wavelengths to examine the energy transfer process in the present Dy3+/Sm3+ co-activated TWKZBi glass via altering the concentration of Sm3+ ions. The emission profiles with varying temperatures from RT to 448 K indicate the good thermal stability of the prepared TWKZBiDySm glasses. Therefore, the prominent results confirm that the prepared TWKZBiDySm glasses will be beneficial for white light and other fascinating photonic applications. [Display omitted] • Dy3+/Sm3+ co-activated tungstate-tellurite (TWKZBiDySm) glasses synthesized. • Emitting color can be tuned from warm white to orange-red with dopant concentration. • Energy transfer from Dy3+ to Sm3+ ions confirmed via theoretical models. • TWKZBiDySm glasses exhibit excellent thermal stability with high activation energy. • Optimized glass could be a potential candidate for w-LEDs and photonic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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7. Wireless Light Fidelity Channel Capacity Improvement Using Sparse Sampled Non-Orthogonal Frequency Shift Keying
- Author
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Daewoong Cheong, Sang Min Yoon, Gangjoon Yoon, Dongsun Seo, and Yong-Yuk Won
- Subjects
Light emitting diodes ,light fidelity ,luminescent devices ,microwave photonics ,non-orthogonal frequency shift keying ,phosphorescence ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
A new technique, which can increase the wireless light fidelity channel capacity based on the white light emitting diode, is proposed. It is implemented by using the non-orthogonal frequency shift keying and the sparse carrier sampling at the same time. The proposed method is verified by using the 1-meter wireless visible light communication link with the 30-MHz frequency response. The maximum power penalty due to the sparse carrier sampling is 6 dB at the compression ratio of 62.5 %. The bit error rate of $9.5\times 10^{-4}$ is measured at the frequency spacing of 0.1 MHz (1% of 10-MHz RF carrier). The wireless channel capacity of 130 Mb/s, which corresponds to 13 times of on-off keying-non-return to zero signal (10Mb/s), is obtained at the compression ratio of 70 % using the proposed technique. We also confirm that the 16-NoFSK signal with the 26-dB input signal to noise ratio can be recovered even at the compression ratio of 75 % when the received optical power is more than -6 dBm.
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- 2019
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8. Design of a Multimode Interferometer-Based Mid-Infrared Multispecies Gas Sensor.
- Author
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Bodiou, Loic, Dumeige, Yannick, Normani, Simone, Louvet, Geoffrey, Nemec, Petr, Nazabal, Virginie, and Charrier, Joel
- Abstract
A $1\times 2$ multimode interferometer beam splitter based on mid-infrared emitting chalcogenides waveguides is designed. This device multiplexes mid-infrared light in two channels whose respective passbands overlap either CO2 or CO absorption bands, respectively between 4.20- $4.32~\mu \text{m}$ and 4.50- $4.86~\mu \text{m}$. The proposed device offers a low-cost solution for monolithic combination of broadband on-chip mid-infrared light emission with dispersive spectroscopic element devoted to mid-IR multigas sensing applications. Based on restrictive interference mechanism in a $1\times 2$ multimode interferometer, the multimode section dimensions (width and length) are engineered to increase the imbalance between the two ports for the two passbands and consequently to increase the output contrast ratio. Tolerances to variations from the optimum device design resulting from processing conditions (materials fabrication and sputtering, photolithography and dry etching steps) are assessed. In particular, the $1\times 2$ multimode interferometer diplexer spectral transmission is investigated as a function of deposited film refractive index and multimode section dimensions (width and length) deviation from designed values. Input and output ports tapering is introduced to reduce the device insertion loss. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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9. Polymerizable Oxime Esters: An Efficient Photoinitiator with Low Migration Ability for 3D Printing to Fabricate Luminescent Devices.
- Author
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Qiu, Wanwan, Zhu, Junzhe, Dietliker, Kurt, and Li, Zhiquan
- Subjects
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THREE-dimensional printing , *LIGHT sources , *ESTERS , *VISIBLE spectra , *LED lamps , *OXIME derivatives , *ACRYLATES - Abstract
The development of novel visible light photoinitiators (PIs) with low mobility for 3D printing will open up new applications for photopolymerization. In this work, a polymerizable visible light PI DCCA containing an oxime acryloyl ester structure was designed and synthesized. Its linear absorption has a maximum in the visible region (400–480 nm), overlapping well with the emission spectra of conventional blue light sources, and it can effectively induce acrylate polymerization under irradiation with a 450 nm LED lamp. In addition, migration of DCCA in the 3D printed samples is very low compared with DCCB, which has a similar structure but a phenyl moiety instead of the copolymerizable acrylate as the oxime ester group. The utility of DCCA in 3D printing was demonstrated by printing a 3D object with challenging geometric features with high resolution and accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
10. Luminescent Lanthanide-Based Sensor for H2O Detection in Aprotic Solvents and D2O.
- Author
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Gontcharenko, Victoria E., Lunev, Alexey M., Taydakov, Ilya V., Korshunov, Vladislav M., Drozdov, Andrey A., and Belousov, Yury A.
- Abstract
Applied methods for detecting water impurities in organic solvents, such as Fischer titration, include wayward equipment and toxic reagents. This method is inapplicable for detecting H2O in D2O, but suitable techniques like NMR-, IR-, and mass-spectrometry are costly. We report a low-cost, novel luminescent sensor material based on terbium-europium 3D MOF compound developed for facile, portable, and disposable monitoring of water quantities. Our sensor is able to determine water traces in D2O and aprotic organic solvents. Treating the material to solvent leads to the change in intensities ratio of terbium and europium bands in emission spectra depending of water content and nature of solvent. For D2O calibrating plot $\text{I}_{\mathrm {Eu}}/\text{I}_{\mathrm {Tb}}$ –%H2O is linear whereas for dioxane and acetonitrile the dependence becomes linear in the coordinates $\text{I}_{\mathrm {Eu}}/\text{I}_{\mathrm {Tb}}$ -ln(%H2O). The results reveal the potential application of developed sensor for ratiometric quantitation of H2O admixtures in D2O, organic solvents, transformer oil, etc. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
11. Design Principles and Material Engineering of ZnS for Optoelectronic Devices and Catalysis.
- Author
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Xu, Xiaojie, Li, Siyuan, Chen, Jiaxin, Cai, Sa, Long, Zhenghao, and Fang, Xiaosheng
- Subjects
- *
ZINC selenide , *OPTOELECTRONIC devices , *SEMICONDUCTORS , *PHOTODETECTORS , *LUMINESCENT probes - Abstract
Abstract: ZnS, as one of the first semiconductors discovered and a rising material star, has embraced exciting breakthroughs in the past few years. To shed light on the design principles and engineering techniques of ZnS for improved/novel optoelectronic properties, the fundamental mechanisms and commonly employed strategies are proposed in this review. Recent progress on modifications of ZnS allows it to be extensively and effectively used in versatile applications, including transparent conductors, UV photodetectors, luminescent devices, and catalysis, which are clearly and comprehensively summarized in this work. Novel functional devices springing up from the newly developed ZnS‐based materials are highlighted as well. This review not only provides a scientific insight into the advances of ZnS‐based materials, but also touches on the future opportunities in this inspiring field. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
12. Photochemistry and Photophysics of Coordination Compounds: Lanthanides
- Author
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Leonard, Joseph P., Nolan, Claire B., Stomeo, Floriana, Gunnlaugsson, Thorfinnur, Balzani, Vincenzo, editor, and Campagna, Sebastiano, editor
- Published
- 2007
- Full Text
- View/download PDF
13. A Flip-Over Plasmonic Structure for Photoluminescence Enhancement of Encapsulated WS2 Monolayers
- Author
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Jianting Ye, Puhua Wan, Qihong Chen, Le Zhang, Chunrui Han, Oleksandr Zheliuk, Minpeng Liang, Xiaoli Peng, and Device Physics of Complex Materials
- Subjects
Photoluminescence ,Materials science ,business.industry ,Band gap ,luminescent devices ,plasmonic structures ,2D materials ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Transition metal ,WS monolayers ,Monolayer ,Optoelectronics ,Photonics ,hexagonal boron nitride ,business ,Absorption (electromagnetic radiation) ,Plasmon ,Excitation ,plasmon-enhanced photoluminescence - Abstract
Transition metal dichalcogenide (TMD) monolayers, with their direct band gaps, have attracted wide attention from the fields of photonics and optoelectronics. However, monolayer semiconducting TMDs generally suffer from low excitation absorption and emission efficiency, limiting their further applications. Here a flip-over plasmonic structure comprised of silver nano-disk arrays supporting a WS2 monolayer sandwiched by hexagonal boron nitride (h-BN) layers is demonstrated. The flip-over configuration optimizes the optical process with a free excitation/emission path from the top and a strong plasmonic interaction from the bottom. As a result, the photoluminescence from the TMD monolayers can be greatly enhanced more than tenfold by optimizing the metasurface, which can be further improved nearly tenfold by optimizing the thickness of bottom h-BN. This study shows the advantages of using the flip-over structure, where the plasmonic interaction between the metasurface and TMDs can be tuned by introducing optimized plasmonic arrays and h-BN layers with suitable thickness. This hybrid device configuration paves a reliable platform to study the light–matter interaction, achieving highly efficient plasmonic TMD devices.
- Published
- 2021
14. Signal amplification of fiber integrated X-ray detector and energy independence
- Author
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D. Tonneau, Anthony Gonçalves, Agnès Tallet, Sree Bash Chandra Debnath, Julien Darreon, Carole Fauquet, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Institute Paoli-Calmettes, Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), This project has received funding from the EuropeanUnion’s Horizon 2020 Research and Innovation Programunder the Marie Skłodowska-Curie grant agreementNo.713750. It has also been carried out with the financialsupport of the Regional Council of Provence- Alpes-Côted’Azur and with the financial support of the A*MIDEXproject funded by the French Government, managed by theFrench National Research Agency (ANR)(n° ANR- 11-IDEX-0001-02, Investissements d'Avenir). This work was alsosupported by Initiative d'Excellence d'Aix-MarseilleUniversité - A*Midex AMX-18-UNT-018., European Project: 713750,H2020,H2020-MSCA-COFUND-2015,DOC2AMU(2016), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Paoli-Calmettes, and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Aix Marseille Université (AMU)
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Optical fiber ,Materials science ,Luminescence ,Physics::Instrumentation and Detectors ,X-ray detector ,Gamma ray detection ,Particle beam measurements ,Scintillator ,01 natural sciences ,Signal ,Particle detector ,law.invention ,Radiation dosage ,[SPI]Engineering Sciences [physics] ,law ,Biomedical applications of radiation ,Dosimetry ,X-rays ,Optical fiber devices ,Irradiation ,Electrical and Electronic Engineering ,Instrumentation ,ComputingMilieux_MISCELLANEOUS ,[PHYS]Physics [physics] ,business.industry ,010401 analytical chemistry ,Detector ,Optical fiber sensors ,X-ray detectors ,0104 chemical sciences ,Radiation detectors ,Oncology ,Optoelectronics ,Luminescent devices ,Photonics ,business - Abstract
International audience; We developed a high spatial resolution and sensitive detector particularly suitable for radiation dose measurements in radiotherapy at small fields and X-ray imaging applications. The detector is based on a silica optical fiber whose sensitive terminal is functionalized by grafting Ag-doped ZnS scintillating materials that emit blue luminescence under X-ray irradiation. Due to the small scintillating head of the detector, the acquisition signal is quite low, and it is measured by a sensitive photon counter plugged at the other terminal of the fiber. The weaker signal can be enhanced significantly by adding a metal coating over the scintillator. Therefore, this study presents the effect of metal thickness and density on the signal amplification at high irradiation energies of 6 MeV and 15 MeV using a Linear Accelerator (LINAC). In addition, the stem effect was characterized for regular to small field beam size and shows that the detector is almost free from stem contribution during high energy irradiation.
- Published
- 2021
15. Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries.
- Author
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Jursinic, Paul A.
- Subjects
- *
RADIATION doses , *RADIATION dosimetry , *LUMINESCENCE , *SENSITIVITY analysis , *MASS density gradients , *IONIZATION chambers - Abstract
Purpose: A type of in vivo dosimeter, an optically stimulated luminescent dosimeter, OSLD, may have dose sensitivity that depends on the angle of incidence of radiation. This work measures how angular dependence of a nanoDot changes with the geometry of the phantom in which irradiation occurs and with the intrinsic structure of the nanoDot. Methods: The OSLDs used in this work were nanoDot dosimeters (Landauer, Inc., Glenwood, IL), which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). Dose to the OSLDs was delivered by 6 MV x-rays. NanoDots with various intrinsic sensitivities were irradiated in numerous phantoms that had geometric shapes of cylinders, rectangles, and a cube. Results: No angular dependence was seen in cylindrical phantoms, cubic phantoms, or rectangular phantoms with a thickness to width ratio of 0.3 or 1.5. An angular dependence of 1% was observed in rectangular phantoms with a thickness to width of 0.433-0.633. A group of nanoDots had sensitive layers with mass density of 2.42-2.58 g/cm³ and relative sensitivity of 0.92-1.09 and no difference in their angular dependence. Within experimental uncertainty, nanoDot measurements agree with a parallel-plate ion chamber at a depth of maximum dose. Conclusions: When irradiated in cylindrical, rectangular, and cubic phantoms, nanoDots show a maximum angular dependence of 1% or less at an incidence angle of 90?. For a sample of 78 new nanoDots, the range of their relative intrinsic sensitivity is 0.92-1.09. For a sample of ten nanoDots, on average, the mass in the sensitive layer is 73.1% Al2O3:C and 26.9% polyester. The mass density of the sensitive layer of a nanoDot disc is between 2.42 and 2.58 g/cm³. The angular dependence is not related to Al2O3:C loading of the nanoDot disc. The nanoDot at the depth of maximum dose has no more angular dependence than a parallel-plate ion chamber. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
16. Dosimetric verification of lung cancer treatment using the CBCTs estimated from limited-angle on-board projections.
- Author
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Zhang, You, Yin, Fang‐Fang, and Ren, Lei
- Subjects
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LUNG cancer treatment , *RADIATION dosimetry , *CONE beam computed tomography , *MEDICAL errors , *STEREOTACTIC radiotherapy , *LUNG anatomy - Abstract
Purpose: Lung cancer treatment is susceptible to treatment errors caused by interfractional anatomical and respirational variations of the patient. On-board treatment dose verification is especially critical for the lung stereotactic body radiation therapy due to its high fractional dose. This study investigates the feasibility of using cone-beam (CB)CT images estimated by a motion modeling and free-form deformation (MM-FD) technique for on-board dose verification. Methods: Both digital and physical phantom studies were performed. Various interfractional variations featuring patient motion pattern change, tumor size change, and tumor average position change were simulated from planning CT to on-board images. The doses calculated on the planning CT (planned doses), the on-board CBCT estimated by MM-FD (MM-FD doses), and the on-board CBCT reconstructed by the conventional Feldkamp-Davis-Kress (FDK) algorithm (FDK doses) were compared to the on-board dose calculated on the "gold-standard" on-board images (gold-standard doses). The absolute deviations of minimum dose (?Dmin), maximum dose (?Dmax), and mean dose (?Dmean), and the absolute deviations of prescription dose coverage (?V100%) were evaluated for the planning target volume (PTV). In addition, 4D on-board treatment dose accumulations were performed using 4D-CBCT images estimated by MM-FD in the physical phantom study. The accumulated doses were compared to those measured using optically stimulated luminescence (OSL) detectors and radiochromic films. Results: Compared with the planned doses and the FDK doses, the MM-FD doses matched much better with the gold-standard doses. For the digital phantom study, the average (± standard deviation) ?Dmin, ?Dmax, ?Dmean, and ?V100% (values normalized by the prescription dose or the total PTV) between the planned and the gold-standard PTV doses were 32.9% (±28.6%), 3.0% (±2.9%), 3.8% (±4.0%), and 15.4% (±12.4%), respectively. The corresponding values of FDK PTV doses were 1.6% (±1.9%), 1.2% (±0.6%), 2.2% (±0.8%), and 17.4% (±15.3%), respectively. In contrast, the corresponding values of MM-FD PTV doses were 0.3% (±0.2%), 0.9% (±0.6%), 0.6% (±0.4%), and 1.0% (±0.8%), respectively. Similarly, for the physical phantom study, the average ?Dmin, ?Dmax, ?Dmean, and ?V100% of planned PTV doses were 38.1% (±30.8%), 3.5% (±5.1%), 3.0% (±2.6%), and 8.8% (±8.0%), respectively. The corresponding values of FDK PTV doses were 5.8% (±4.5%), 1.6% (±1.6%), 2.0% (±0.9%), and 9.3% (±10.5%), respectively. In contrast, the corresponding values of MM-FD PTV doses were 0.4% (±0.8%), 0.8% (±1.0%), 0.5% (±0.4%), and 0.8% (±0.8%), respectively. For the 4D dose accumulation study, the average (± standard deviation) absolute dose deviation (normalized by local doses) between the accumulated doses and the OSL measured doses was 3.3% (±2.7%). The average gamma index (3%/3 mm) between the accumulated doses and the radiochromic film measured doses was 94.5% (±2.5%). Conclusions: MM-FD estimated 4D-CBCT enables accurate on-board dose calculation and accumulation for lung radiation therapy. It can potentially be valuable for treatment quality assessment and adaptive radiation therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
17. Comparison of CFL and LED lamp - harmonic disturbances, economics (cost and power quality) and maximum possible loading in a power system.
- Author
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George, Victor, Bagaria, Aayush, Singh, Prakash, Pampattiwar, Sankalp Rajeev, and Periwal, Swati
- Abstract
The desire to reduce electrical loading by using energy efficient lighting has resulted in a high level of interest in replacing conventional incandescent lamp with Compact Fluorescent Lamps and LED lamps. However, their high harmonic content was always a problem for the power quality of the power system networks, especially the ones with a considerable share of nonlinear loads. The problem of harmonics cannot be neglected in cases of installations with high lighting load. This paper presents an analysis of harmonics in a network where lighting is one of the main loads. CFLs and LED lamps with electronic gear are characterized by extremely distorted current, with high total current harmonic distortions. Hence they cause a significant voltage distortion in electrical installations. The network is simulated using the impedance network model, in PSCAD®/EMTDC™ software. A comparative analysis is performed on the power quality, maximum loading and economics of CFL lamps and LED lamps. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
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18. Design of a multimode interferometer-based mid-infrared multispecies gas sensor
- Author
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Simone Normani, Loïc Bodiou, Petr Nemec, Joël Charrier, Yannick Dumeige, Virginie Nazabal, Geoffrey Louvet, Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Department of Graphic Arts and Photophysics [University of Pardubice], Faculty of Chemical Technology [University of Pardubice], University of Pardubice-University of Pardubice, Institut des Sciences Chimiques de Rennes (ISCR), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Région Bretagne, project No. 19-24516S, Grantová Agentura České Republiky, Lannion Trgor Communaut, Conseil Dpartemental des Ctes dArmor, ANR-17-CE09-0028,MID-VOC,Circuit optique intégré à base matériaux poreux pour la détection de composés organiques volatiles dans le moyen infrarouge(2017), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
- Subjects
Materials science ,Interference (wave propagation) ,7. Clean energy ,01 natural sciences ,law.invention ,Photonic integrated circuits ,Amorphous materials ,Optics ,law ,Insertion loss ,[CHIM]Chemical Sciences ,Electrical and Electronic Engineering ,Diplexer ,Instrumentation ,Infrared spectroscopy ,Optical strip waveguide components ,ComputingMilieux_MISCELLANEOUS ,Multi-mode optical fiber ,business.industry ,010401 analytical chemistry ,Photonic integrated circuit ,Chalcogenides thin films ,Environmental monitoring ,[CHIM.MATE]Chemical Sciences/Material chemistry ,0104 chemical sciences ,Mid-Infrared sensors ,Interferometry ,Optical Waveguides and Components ,Integrated circuit design ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,Light emission ,Luminescent devices ,Praseodymium Category: Optical Waveguides and Components ,business ,Beam splitter - Abstract
A $1\times 2$ multimode interferometer beam splitter based on mid-infrared emitting chalcogenides waveguides is designed. This device multiplexes mid-infrared light in two channels whose respective passbands overlap either CO2 or CO absorption bands, respectively between 4.20- $4.32~\mu \text{m}$ and 4.50- $4.86~\mu \text{m}$ . The proposed device offers a low-cost solution for monolithic combination of broadband on-chip mid-infrared light emission with dispersive spectroscopic element devoted to mid-IR multigas sensing applications. Based on restrictive interference mechanism in a $1\times 2$ multimode interferometer, the multimode section dimensions (width and length) are engineered to increase the imbalance between the two ports for the two passbands and consequently to increase the output contrast ratio. Tolerances to variations from the optimum device design resulting from processing conditions (materials fabrication and sputtering, photolithography and dry etching steps) are assessed. In particular, the $1\times 2$ multimode interferometer diplexer spectral transmission is investigated as a function of deposited film refractive index and multimode section dimensions (width and length) deviation from designed values. Input and output ports tapering is introduced to reduce the device insertion loss.
- Published
- 2020
19. Scintillation Screen Studies for High-Dose Ion Beam Applications.
- Author
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Gutlich, Eiko, Forck, Peter, Ensinger, Wolfgang, and Walasek-Hohne, Beata
- Subjects
- *
SCINTILLATION counters , *LUMINESCENCE , *ION bombardment , *PHOSPHORS , *PARTICLE beams - Abstract
Scintillating screens are commonly used at accelerator facilities. However, their imaging qualities are not well understood, especially for high-current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies of 4.8 and 11.4 MeV/u. For ion beam applications, the exact reproduction of the beam profile is of great importance. Due to the impact by ions, the dose rate during beam delivery is more than 10 orders of magnitude higher as for other applications of scintillators in typical nuclear physics experiments. To validate the imaging quality of the scintillators, different profile measurement methods are compared. Ceramic Al2O3 showed the best results compared to other ceramics like ZrO2:Y or quartz glass Herasil 102. The imaging properties of the materials can depend significantly on the ion energy. For Al2O3 irradiated with a Ca beam the of 4.8 MeV/u, the results agree with the reference methods. However, for 11.4 MeV/u, the screen image does not reflect the beam distribution, which cannot be attributed to material degradation. A model is under development taking into account the radial dose distribution along the ion track as well as the overlap of tracks. For Al2O3, this model can describe the observed saturation effect and is able to reconstruct saturated images. The basics and applications of this model are discussed. Detailed spectroscopic investigations were performed to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectra with respect to the beam intensity was found for most of the scintillators. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
20. Solid-State Lighting: An Integrated Human Factors, Technology, and Economic Perspective.
- Author
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TSAO, JEFFREY Y., COLTRIN, MICHAEL E., CRAWFORD, MARY H., and SIMMONS, JERRY A.
- Subjects
LIGHTING ,LIGHT sources ,ERGONOMICS ,ILLUMINATORS ,COST analysis - Abstract
Solid-state lighting is a rapidly evolving technology, now virtually certain to someday displace traditional lighting in applications ranging from the lowest-power spot illuminator to the highest-power area illuminator. Moreover, it has considerable headroom for continued evolution even after this initial displacement. In this paper, we present a high-level overview of solid-state lighting, with an emphasis on white lighting suitable for general illumination. We characterize in detail solid-state lighting's past and potential-future evolution using various performance and cost metrics, with special attention paid to inter-relationships between these metrics imposed by human factors, technology, and economic considerations. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
21. Scintillation Screen Investigations for High-Current Ion Beams.
- Author
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Gütlich, Eiko, Forck, Peter, Ensinger, Wolfgang, and Walasek-Höhne, Beata
- Subjects
- *
ION bombardment , *SCINTILLATORS , *RADIATION , *IRRADIATION , *PARTICLE beams - Abstract
At GSI, the Helmholtz Centre for Ion Research, the properties of scintillation screens, irradiated by an ion beam, were studied. For various materials, the different ion beams H+, C2+, Ar10+, Ni9+, Ta24+, and U28+ in the energy range from 4.8-11.4 MeV/u were applied with currents ranging from nA to some mA, delivered by the heavy ion LINAC at GSI. Scintillation screens are widely used for qualitative ion beam profile monitoring. However, precise measurements of the beam profile yield ambivalent results, especially for high beam currents. Thus, the properties (light yield, beam width, and higher statistical moments) of well-known scintillators, ceramic materials, and different quartz glasses are compared. The image of each ion beam pulse was recorded by a digital CCD camera and individually evaluated. A change of the imaged ion beam shape was observed for some materials. The recorded beam profile shows dependence on the scintillator material. Even for low beam intensities (17 nA) a difference in the beam width of about 25% was measured. Additionally, the light yield and beam width depend significantly on the screen temperature, which is increased by the ion impact. For ZrO2 : Al the influence of the screen temperature on the statistical moments was investigated. Furthermore the spectra of scintillation screens were studied in the region from 350 to 750 nm for the irradiation with H+ and Ta24+ ions. Empirical results are discussed and give rise to further investigations on the materials. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
22. Influence of Dislocation Loops on the Near-Infrared Light Emission From Silicon Diodes.
- Author
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Tu Hoang, Holleman, Jisk, LeMinh, Phuong, Schmitz, Jurriaan, Mchedlidze, Teimuraz, Arguirov, Tzanimir, and Kittler, Martin
- Subjects
- *
SILICON diodes , *INFRARED radiation , *INTEGRATED circuits , *DIODES , *LIGHT sources , *ELECTRONIC circuits - Abstract
The infrared light emission of forward-biased silicon diodes is studied. Through ion implantation and anneal, dislocation loops were created near the diode junction. These loops suppress the light emission at the band-to-band peak around 1.1 µm. The so-called D1 line at 1.5 µm is strongly enhanced by these dislocation loops. We report a full study of photoluminescence and electroluminescence of these diodes. The results lead to new insights for the manufacturing approach of practical infrared light sources in integrated circuits. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
23. An optical fiber sensor for the detection of germicidal UV irradiation using narrowband luminescent coatings.
- Author
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McSherry, M., Fitzpatrick, C., and Lewis, E.
- Abstract
A narrowband luminescent coating for germicidal 254-nm ultraviolet optical fiber sensors has been developed. A mixture of phosphor and epoxy is used for this coating. The luminescent-clad sensing principle uses a fiber, which has had its cladding and jacket both removed, and a photoluminescent coating replacing the cladding. As the coating luminesces, part of the emission is coupled to the fiber core through evanescent wave coupling. The combined absorption spectrum of the phosphor and the transmission spectrum of the epoxy result in a narrow sensitivity band of wavelengths being detected, centered around 254 nm. The absorption of the 254-nm radiation incident on the coating is emitted as visible light in the optical fiber sensor. This paper describes the development and testing of this narrowband coating using a spectrophotometer to examine its responsivity, and a luminescent-coated optical fiber sensor is compared with a UV photodiode when illuminated by a UV lamp. This optical fiber sensor monitors the output of UV lamps for stabilization and control purposes. [ABSTRACT FROM PUBLISHER]
- Published
- 2004
- Full Text
- View/download PDF
24. CMOS chip as luminescent sensor for biochemical reactions.
- Author
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Ude Lu, Hu, B.C.-P., Yu-Chuan Shih, Yuh-Shyong Yang, Chung-Yu Wu, Chiun-Jye Yuan, Ming-Dou Ker, Tung-Kung Wu, Yaw-Kuen Li, You-Zung Hsieh, Wensyang Hsu, and Chin-Teng Lin
- Abstract
We describe a novel biochemical sensing method and its potential new biosensing applications. A light-sensitive complementary metal oxide semiconductor (CMOS) chip prepared through a standard 0.5-μm CMOS process was developed for measuring biochemical reactions. A light producing enzymatic reaction catalyzed by horseradish peroxidase (HRP) was designed as a platform reaction to determine the concentration of hydrogen peroxide (H2O2) by the CMOS chip with a standard semiconductor parameter analyzer (HP4145). The kinetics of enzymatic reaction were determined and compared with a standard and sophisticated fluorometer (Hitachi F-4500) in a biochemical laboratory. Similar results were obtained by both instruments. Using glucose oxidase as an example, we further demonstrated that the HRP platform can be used to determine other H2O2 producing reactions with the CMOS system. The result points to an important application of the CMOS chip in biological measurements and in diagnosis of various health factors. [ABSTRACT FROM PUBLISHER]
- Published
- 2003
- Full Text
- View/download PDF
25. Design Criteria for Micro-Optical Tandem Luminescent Solar Concentrators
- Author
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John F. Geisz, Harry A. Atwater, Colton R. Bukowsky, Zach Nett, Junwen He, Ralph G. Nuzzo, Lu Xu, A. Paul Alivisatos, Benjamin G. Lee, Ognjen Ilic, Haley Bauser, and David R. Needell
- Subjects
Materials science ,luminescent devices ,quantum dots ,tandem PV ,02 engineering and technology ,III-V concentrator photovoltaics ,01 natural sciences ,Waveguide (optics) ,010309 optics ,chemistry.chemical_compound ,0103 physical sciences ,Electrical and Electronic Engineering ,Quantum Physics ,Tandem ,Cadmium selenide ,business.industry ,Photovoltaic system ,Energy conversion efficiency ,Monte Carlo methods ,Materials Engineering ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,chemistry ,Quantum dot ,Luminophore ,Optoelectronics ,Photonics ,0210 nano-technology ,business - Abstract
© 2018 IEEE. Luminescent solar concentrators (LSCs) harness light generated by luminophores embedded in a light-trapping waveguide to concentrate onto smaller cells. LSCs can absorb both direct and diffuse sunlight, and thus can operate as flat plate receivers at a fixed tilt and with a conventional module form factor. However, current LSCs experience significant power loss through parasitic luminophore absorption and incomplete light trapping by the optical waveguide. Here, we introduce a tandem LSC device architecture that overcomes both of these limitations, consisting of a poly(lauryl methacrylate) polymer layer with embedded cadmium selenide core, cadmium sulfide shell (CdSe/CdS) quantum dot (QD) luminophores and an InGaP microcell array, which serves as high bandgap absorbers on the top of a conventional Si photovoltaic. We investigate the design space for a tandem LSC, using experimentally measured performance parameters for key components, including the InGaP microcell array, CdSe/CdS QDs, and spectrally selective waveguide filters. Using a Monte Carlo ray-tracing model, we compute the power conversion efficiency for a tandem LSC module with these components to be 29.4% under partially diffuse illumination conditions. These results indicate that a tandem LSC-on-Si architecture could significantly improve upon the efficiency of a conventional Si photovoltaic cell.
- Published
- 2018
26. Diode-Laser-Pumped Glass-Clad Ti:Sapphire Crystal-Fiber-Based Broadband Light Source.
- Author
-
Kuang-Yu Hsu, Dong-Yo Jheng, Yi-Han Liao, Tuan-Shu Ho, Chien-Chih Lai, and Sheng-Lung Huang
- Abstract
Glass-clad crystal fibers were grown using the codrawing laser-heated pedestal growth method. Both single-clad and double-clad structures were attempted. Using a 446-nm laser diode as the pump, 2.45 mW of collimated broadband emission was generated with a 3-dB bandwidth of 180 nm. As much as 7.7 mW of output power with a 3-dB bandwidth of 182 nm was generated using a 532-nm solid-state pump laser. The broadband light source is advantageous to use in optical coherence tomography with an axial resolution of 1.5 in air and a low image pixel crosstalk. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
27. A Study of Semitransparent Cathodes on the Performance of Top-Emitting Polymer Light-Emitting Diodes.
- Author
-
Sung-Nien Hsieh, Tzu-Yin Kuo, Lai-Wan Chong, Ten-Chin Wen, Fun-Shun Yang, Tzung-Fang Guo, and Chia-Tin Chung
- Published
- 2009
- Full Text
- View/download PDF
28. Strong Efficiency Improvement of SOI-LEDs Through Carrier Confinement.
- Author
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Tu Hoang, Phuong Leminh, Holleman, Jisk, and Schmitz, Jurriaan
- Subjects
SILICON-on-insulator technology ,ELECTRIC insulators & insulation ,SEMICONDUCTORS ,LIGHT emitting diodes ,SEMICONDUCTOR diodes - Abstract
Contemporary silicon light-emitting diodes in silicon-on-insulator (SOI) technology suffer from poor efficiency compared to their bulk-silicon counterparts. In this letter, we present a new device structure where the carrier injection takes place through silicon slabs of only a few nanometer thick. Its external quantum efficiency of 1.4 · 10
-4 at room temperature, with a spectrum peaking at 1130 nm, is almost two orders higher than reported thus far on SOI. The structure diminishes the dominant role of nonradiative recombination at the n+ and p+ contacts, by confining the injected carriers in an SOI peninsula. With this approach, a compact infrared light source can be fabricated using standard semiconductor processing steps. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
- View/download PDF
29. The Effect of Dislocation Loops on the Light Emission of Silicon LEDs.
- Author
-
Tu Hoang, Phuong LeMinh, Holleman, Jisk, and Schmitz, Jurriaan
- Subjects
INTEGRATED optics ,OPTOELECTRONICS ,LIGHT emitting diodes ,LIGHT sources ,OPTOELECTRONIC devices ,SEMICONDUCTORS ,SILICON - Abstract
Remarkably strong infrared light emission was recently observed from silicon p
+ -n diodes. In several publications a causal relation is proposed between the larger-than-expected light intensity and the existence of lattice damage around the junction. In this letter, we present direct experimental evidence that lattice damage is in fact detrimental to the efficiency of light emission of silicon LEDs. The experiments call for a revision of the explanation for strong light emission in this type of devices. [ABSTRACT FROM AUTHOR]- Published
- 2006
- Full Text
- View/download PDF
30. Influence of dislocation loops on the near infrared light emission from silicon diodes
- Author
-
Teimuraz Mchedlidze, P. LeMinh, Martin Kittler, T. Hoang, J. Holleman, Tzanimir Arguirov, and Jurriaan Schmitz
- Subjects
Silicon ,Materials science ,Infrared ,chemistry.chemical_element ,Electroluminescence ,Optoelectronic devices ,law.invention ,Optics ,law ,Semiconductor devices ,Integrated optoelectronics ,Light-emitting diodes (LEDs) ,Light sources ,Electrical and Electronic Engineering ,Diode ,business.industry ,Integrated optics ,Semiconductor device ,Electronic, Optical and Magnetic Materials ,Dislocation loops ,Semiconductor device fabrication ,Ion implantation ,chemistry ,Optoelectronics ,Light emission ,Luminescent devices ,business ,Light-emitting diode - Abstract
The infrared light emission of forward-biased silicon diodes is studied. Through ion implantation and anneal, dislocation loops were created near the diode junction. These loops suppress the light emission at the band-to-band peak around 1.1 mum. The so-called D1 line at 1.5 mum is strongly enhanced by these dislocation loops. We report a full study of photoluminescence and electroluminescence of these diodes. The results lead to new insights for the manufacturing approach of practical infrared light sources in integrated circuits.
- Published
- 2007
31. Introducing novel light management to design a hybrid high concentration photovoltaic/water splitting system
- Author
-
Videira, Jose J. H., Barnham, Keith W. J., Hankin, Anna, Connolly, James P., Leak, Matthew, Johnson, Jonathan, Kelsall, Geoff H., Kennedy, Ken, Roberts, John S., Alexander Cowan, Chatten, Amanda J., IEEE, Imperial College Trust, Universitat Politècnica de València (UPV), and Nanophotonics Technology Center
- Subjects
010302 applied physics ,Physics ,Photon ,ray tracing ,business.industry ,luminescent devices ,Photovoltaic system ,Luminescent solar concentrator ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,Photocathode ,[SPI]Engineering Sciences [physics] ,Optics ,solar cells ,0103 physical sciences ,Radiative transfer ,Optoelectronics ,Water splitting ,photoluminescence ,Spontaneous emission ,0210 nano-technology ,business ,Dark current - Abstract
International audience; We present a novel way to utilize high-concentration photovoltaic (HCPV) radiative losses and diffuse light, otherwise unused in conventional HCPV systems, to power an Imperial College designed photoelectrochemical reactor (PECR) producing H 2 fuel through water splitting. A high efficiency photovoltaic (HEPV) is embedded inside a Luminescent Solar Concentrator (LSC). Edge emission from the radiative recombination loss mechanism in the HEPV is guided within the LSC to the PECR photocathode, whilst the LSC emitted light is guided to the photoanode. The photon streams can be independently optimised in intensity and wavelength. We demonstrate how photon streams with balanced intensity can be achieved.
- Published
- 2015
32. Tištěná elektronika - OLED
- Author
-
Syrový, Tomáš, Valigura, Marek, Syrový, Tomáš, and Valigura, Marek
- Abstract
Táto bakalářská práca sa zaoberá súhrnom informácií a vedomostí o aplikácii tlačových technik při výrobe OLED., This thesis deals with summary information and knowledge of the application of printing techniques in the production of OLED., Katedra polygrafie a fotofyziky, prof. Ing. Petr Němec, Ph.D.: Co znamená polovodič typu n? Co znamená vodivá a valenční vazva? ing. Jan VAliš, Ph.D.: Čím si vysvětlujete pokles svítivosti u vzorků zhotovených sítotiskem?
- Published
- 2015
33. Luminescent coverglass for improved absorption efficiency in III–V photovoltaic modules.
- Author
-
Nam, W.I., Kang, E.K., Park, H.G., Jun, D.‐H., and Song, Y.M.
- Abstract
An initial demonstration is reported in terms of maximising performance of photovoltaic modules. Experimental results of a triple junction solar cell covered with a 3 mm red‐emitting luminous glass which can be efficiently excited by ultraviolet light indicate that this combination exhibits significantly enhanced efficiency of 36.5% under one‐sun of AM1.5G. Integrating a luminescent (LSC) glass onto modules without converting any fabrication process at the device level is considered to be one of the predominant advantages of this device. Additionally, in order to achieve strong visible emission, it is mandatory to determine a thickness of LSC coverglass due to the edge reflection. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
34. Photodetectors: Design Principles and Material Engineering of ZnS for Optoelectronic Devices and Catalysis (Adv. Funct. Mater. 36/2018).
- Author
-
Xu, Xiaojie, Li, Siyuan, Chen, Jiaxin, Cai, Sa, Long, Zhenghao, and Fang, Xiaosheng
- Subjects
- *
MAGAZINE covers , *PHOTODETECTORS , *OPTOELECTRONIC devices - Published
- 2018
- Full Text
- View/download PDF
35. Blue organic light-emitting diodes based on pyrazoline phenyl derivative
- Author
-
Xiao Wei Sun, Juozas V. Grazulevicius, Zenon Hotra, Pavlo Stakhira, Alexander V. Kukhta, Ausra Tomkeviciene, L. Voznyak, Nadzeya A. Kukhta, Dmytro Volyniuk, Vladyslav Cherpak, S. V. Khomyak, Jurate Simokaitiene, Hilmi Volkan Demir, Demir, Hilmi Volkan, and School of Electrical and Electronic Engineering
- Subjects
Materials science ,Photoluminescence ,Pyrazoline derivative ,Cyclic voltammograms ,Experimental studies ,Pyrazoline ,Peak wavelength ,Electroluminescence ,Optoelectronic devices ,chemistry.chemical_compound ,Indenofluorene ,Vacuum deposition ,Electron-transporting layers ,Phenols ,Blue emitting ,Materials Chemistry ,OLED ,Carbazole derivates ,Pyrazolines ,Blue emission ,Organic light emitting diode ,Carbazole ,business.industry ,Mechanical Engineering ,Blue organic light emitting diodes ,Metals and Alloys ,Blue-emitting ,Electroluminescent Devices ,Condensed Matter Physics ,Organic light-emitting ,Polycyclic aromatic hydrocarbons ,Electronic, Optical and Magnetic Materials ,Organic light emitting diodes (OLED) ,chemistry ,Mechanics of Materials ,Engineering::Electrical and electronic engineering [DRNTU] ,Physical chemistry ,Optoelectronics ,Density functional theory ,Luminescent devices ,business ,Derivative (chemistry) - Abstract
Cataloged from PDF version of article. The results of an experimental study of the electroluminescent device made of ITO/CuI/2,6-di-tert-butyl-4-(2,5-diphenyl-3,4-dihydro-2H-pyrazol-3-yl)-phenol (HPhP)/3,6-Di(9-carbazolyl)-9-(2ethylhexyl) carbazole (TCz1)/Ca:Al with efficacy up to 10.63 cd/A are presented. HPhP provides blue emission with a peak wavelength at 445 nm. The layer of TCz1 acts as an electron-transporting layer. In the framework of density functional theory (DFT) approach the geometry configuration and energy levels of HPhP are found being in a good agreement with spectral and cyclic voltammogram data. (C) 2011 Elsevier B.V. All rights reserved.
- Published
- 2012
36. Electroluminescent device based on AlxGa1-xAs-GaAs quantum well nanostructures
- Author
-
Manimaran, M., Vaya, P.R., and Kanayama, T.
- Subjects
Reactive ion etching ,Lithography ,Ultraviolet lithography ,Semiconductor device manufacture ,Semiconducting gallium arsenide ,Aluminum gallium arsenide quantum wells ,Semiconducting aluminum compounds ,Light emission ,Electric potential ,Carrier concentration ,Luminescent devices ,Chlorine ,Scanning electron microscopy ,Semiconductor quantum wells ,Gallium arsenide quantum well - Abstract
AlGaAs-GaAs based quantum well nanopillar arrays are fabricated by using the UV lithography and the chlorine based reactive ion etching. The nanostructure is fabricated so as to get the confinement of carriers within the i-GaAs quantum well layer of 9 nm thick sandwiched between two barrier layers of Al0.33Ga0.67As of 11 nm thick in order to induce the possible light emission from the quantum well region. The size of pillars is obtained from SEM analysis. The number of pillars available within the 1 ?m2 mesa size is found to be around 400 having the pillar size between 10 and 50 nm. Electroluminescence (EL) is detected from the nanopillars when applying a forward bias voltage of �1.3 V and the emitted light is observed at around 830 nm.
- Published
- 2000
- Full Text
- View/download PDF
37. Trailing edge phenomena in SrS:CeCl3 thin film electroluminescent devices
- Author
-
Karl-Otto Velthaus, B. Hüttl, R. H. Mauch, U. Troppenz, and Publica
- Subjects
Photoluminescence ,Materials science ,strontium compounds ,optical films ,trailing edge ,luminescent devices ,voltage levels ,mean electric field strength ,Electroluminescence ,pel ,multilayer structures ,law.invention ,laser excitation ,el threshold ,Inorganic Chemistry ,law ,photo-induced transferred charge ,Materials Chemistry ,thin film devices ,Trailing edge ,Thin film ,ce3+ ions ,cerium compounds ,electroluminescent displays ,business.industry ,thin film electroluminescent devices ,photo-induced electroluminescence ,voltage pulse ,applied voltage ,Condensed Matter Physics ,Laser ,charge transfer states ,Threshold voltage ,pl intensity ,luminescence of inorganic solids ,radiation quenching ,weakly accelerated electrons ,spectral line intensity ,voltage dependent photoluminescence ,Optoelectronics ,time dependence ,photoluminescence ,quenched pl ,business ,Excitation ,Voltage - Abstract
SrS:CeCl3 based thin film electroluminescent devices in conventional and multilayer structures have been investigated by means of time and voltage dependent photoluminescence (PL) measurements after laser excitation of the Ce3+ ions. It turned out that a significant photo-induced transferred charge as well as photo-induced electroluminescence (PEL) occurs at voltage levels far below the actual EL threshold, mainly in the trailing edge of the voltage pulse. Furthermore, a reduction of the PL intensity by increasing the applied voltage is observed. At EL threshold voltage, the PL intensity is as low as 65-75% of the zero voltage value. These observations are independent of the device structure. The PEL can be described as a partial regain of the quenched PL, being more pronounced in the multilayer case due to a higher mean electric field strength in the SrS:CeCl3 layers. To explain the experimental findings, a quenching caused by weakly accelerated electrons is proposed.
- Published
- 1994
38. Rôle des centres profonds dans la dégradation lente des dispositifs électroluminescents
- Author
-
J.C. Brabant
- Subjects
010302 applied physics ,Physics ,DLTS ,deep centres ,luminescent devices ,active layer ,02 engineering and technology ,021001 nanoscience & nanotechnology ,photocapacitance ,01 natural sciences ,electron hole recombination ,characterisation techniques ,injected carriers ,[PHYS.HIST]Physics [physics]/Physics archives ,0103 physical sciences ,Electron hole recombination ,deep levels ,non radiative recombination process ,photoluminescence ,0210 nano-technology ,electroluminescent devices ,migration mechanisms ,Humanities ,degradation - Abstract
La dégradation lente des dispositifs électroluminescents est généralement attribuée à la recombinaison non (ou faiblement) radiative des porteurs injectés sur des centres profonds qui se concentrent et se fixent dans le volume de la zone active. Les expériences récentes s'efforcent : - d'une part de caractériser et d'identifier les défauts responsables ; - d'autre part, d'étudier les mécanismes de migration et de fixation des défauts dans la zone active. Diverses techniques ont été mises en oeuvre : nous citons la D.L.T.S., la photocapacitance, l'électro- et la photoluminescence. Elles ont permis de détecter dans les différentes couches épitaxiales, la présence d'un petit nombre de centres profonds directement liés à la dégradation du dispositif, et de suivre l'évolution de leur concentration au cours de tests de vieillissement en régime de fonctionnement. Des hypothèses sur l'origine de ces défauts, et les solutions parfois proposées pour leur élimination sont discutées : faces latérales, substrat, zone protonée... Des mécanismes de migration en régime de fonctionnement et de fixation de ces défauts vers la zone active sont exposés.
- Published
- 1980
39. Techniques logiques de commande et animation de structures matricielles électroluminescentes
- Author
-
J. Bernard, G. Batailler, J.C. Besse, and P. Garcia
- Subjects
matrix displays ,ZnS Cu Cl ,media_common.quotation_subject ,luminescent devices ,arsenic compounds ,electroluminescent matrix devices ,emitting performances ,02 engineering and technology ,Art ,Destriau effect ,010402 general chemistry ,021001 nanoscience & nanotechnology ,display systems ,light emitting diodes ,01 natural sciences ,0104 chemical sciences ,visualisation ,[PHYS.HIST]Physics [physics]/Physics archives ,GaAsP ,static information ,gallium compounds ,dynamic information ,0210 nano-technology ,zinc compounds ,media_common - Abstract
Cet article traite de différentes techniques originales d'affichage d'informations statiques ou évolutives sur visualisateurs matriciels. Les supports utilisés sont des structures électroluminescentes au ZnS(Cu/Cl) (à effet Destriau) ou à diodes à injection de porteurs au GaAsP. Des réalisations concrètes d'afficheurs ont permis d'évaluer les performances émissives de ces supports en fonction des différentes techniques exposées.
- Published
- 1973
40. Étude de la variation au cours d'une période de la constante diélectrique complexe d'une cellule électroluminescente
- Author
-
D. Magnant, M. Durvy, and H. Payen de la Garanderie
- Subjects
absorbed power variations ,complex dielectric constant ,[PHYS.HIST]Physics [physics]/Physics archives ,020209 energy ,luminescent devices ,brightness ,0202 electrical engineering, electronic engineering, information engineering ,electroluminescent cell ,02 engineering and technology ,energy balance ,electroluminescence - Abstract
Nous avons calculé, à partir de données expérimentales sur les courants traversant une cellule électroluminescente, les valeurs instantanées de la « constante » diélectrique complexe. Les variations de celle-ci sur une période ont pu être mises en relation avec celles de la luminance et de la puissance absorbée, permettant d'envisager un bilan énergétique de la cellule.
- Published
- 1973
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