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Search results for: LIGHT-EMITTING TRANSISTORS
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Asynchronous Charge Carrier Injection in Perovskite Light-Emitting Transistors
PublicationUnbalanced mobility and injection of charge carriers in metal-halide perovskite light-emitting devices pose severe limitations to the efficiency and response time of the electroluminescence. Modulation of gate bias in methylammonium lead iodide light-emitting transistors has proven effective in increasing the brightness of light emission up to MHz frequencies. In this work, a new approach is developed to improve charge carrier...
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Organic light emitting devices
PublicationW pracy przedstawiono podstawowe procesy fizyczne zachodzące w organicznych emiterach elektroluminescencyjnych oraz parametry techniczne tego typu układów.
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Optical materials for organic light emitting diodes
PublicationW pracy dokonano przeglądu materiałów stosowanych w organicznych diodach elektroluminescencyjnych.
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Emission mechanisms in organic light-emitting diodes
PublicationGlównym przedmiotem opracowania jest powiązanie optycznych i elektrycznych charakterystyk organicznych diod elektroluminescencyjnych. Szczególną uwagę zwrócono na występowanie różnych rodzajów stanów wzbudzenia elektronowego prowadzących do wydajnego świecenia diod elektroluminescencyjnych.
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Organic light-emitting diodes. Principles, characteristics and processes.
PublicationJest to pierwsze monograficzne opracowanie zjawiska elektroluminescencji w organicznych ciałach stałych. W sześciu rozdziałach książki opisano między innymi wytwarzanie stanów wzbudzonych w wyniku rekombinacji ładunku, sposoby zaniku stanów wzbudzonych i ich rozkład przestrzenny, elektryczne i optyczne własności organicznych diod elektroluminescencyjnych oraz procesy warunkujące wydajne świecenie takich diod.
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Photophysical processes in the selected white organic light-emitting diodes
PublicationThe first part discusses history of organic emitters, the scope of the work, phenomena in molecular systems, types of architectures in OLEDs, types of OLEDs emitting white light with examples from the literaturę and a description of the parameters chcracterizing LEDs. The second part describes materials, production of the samples, the measurement systems and results. In chapter 8.1 the results for the OLEDs based on emission from...
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Structural organization of video informative systems on light-emitting diodes
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Green Light-Excitable Ce-Doped Nitridomagnesoaluminate Sr[Mg2Al2N4] Phosphor for White Light-Emitting Diodes
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Light emitting diodes optimisation for secondary metabolites production by Droseraceae plants
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Highly efficient exciplex phosphorescence from organic light-emitting diodes
PublicationW pracy badano fluorescencję ekscypleksową w układzie dendrymer aminowy m-MTDATA(donor elektronu):fenantrolina BPT (akceptor) oraz fosforescencję ekscypleksową w układzie m-MTDATA:organiczny kompleks platyny PtL2Cl. Opisano konstrukcję dwuwarstwowej diody elektrofosforescencyjnej o kwantowej (użytecznej) wydajności świecenia 2.4%.
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High Color Rendering Index of Rb2GeF6:Mn4+ for Light-Emitting Diodes
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Electroabsorption in triphenylamine-based hole-transporting materials for organic light-emitting diodes
PublicationMetodą elektroabsorpcji (EA) badano stany wzbudzenia elektronowego w próżniowo naparowanych warstwach diamin (TPD, TAPC) i dendrymeru aminowego m-MTDATA. Widma EA amin złożonych porównano z widmem monomeru trifenylaminy (TPA). Kształt widm EA świadczy o obecności zdegenerowanych i quasi-zdegenerowanych stanów elektronowych.
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Hydrogen-Containing Na3HTi1–xMnxF8 Narrow-Band Phosphor for Light-Emitting Diodes
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Chromium(III)-Doped Fluoride Phosphors with Broadband Infrared Emission for Light-Emitting Diodes
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Probing Local Structural Changes by Sharp Luminescent Infrared Nanophosphor for Application in Light-Emitting Diodes
PublicationCr3+-doped infrared phosphors are promising candidates for next-generation phosphor-converted infrared light-emitting diodes (LEDs) because they can, in principle, tune and convert the luminescence spectra from an LED chip. However, most studies focus on broad-band Cr3+-doped phosphors, and the control mechanism of Cr3+-doped phosphors with sharp line emissions remains ambiguous. Here, we report LiGa5(1–x)Al5xO8:Cr3+ phosphors...
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Excimer-based red-infrared organic light emitting diodes with very high quantum efficiency
PublicationW pracy opisano konstrukcję wydajnej organicznej ekscymerowej diody EL emitującej światło czerwone i podczerwone z wykorzystaniem organicznego kompleksu platyny.
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Linking Macro- and Micro-structural Analysis with Luminescence Control in Oxynitride Phosphors for Light-Emitting Diodes
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Hidden Structural Evolution and Bond Valence Control in Near-Infrared Phosphors for Light-Emitting Diodes
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Chromium Ion Pair Luminescence: A Strategy in Broadband Near-Infrared Light-Emitting Diode Design
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High-Performance NaK2Li[Li3SiO4]4:Eu Green Phosphor for Backlighting Light-Emitting Diodes
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Study of ZrS3-based field-effect transistors toward the understanding of the mechanisms of light-enhanced gas sensing by transition metal trichalcogenides
PublicationExtending knowledge of the properties of low-dimensional van der Waals materials, including their reactivity to the ambiance, is important for developing innovative electronic and optoelectronic devices. Transition metal trichalcogenides with tunable optical band gaps and anisotropic conductivity are an emerging class among low- dimensional structures with the possibility of gate tunability and photoreactivity. These properties...
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Mixing of excimer and exciplex emission: A new way to improve white light emitting organic electrophosphorescent diodes
PublicationW pracy opisano konstrukcję wydajnych diod elektrofosforescencyjnych emitujących światło białe. Emisja diod pochodzi od trypletowych monomerów PtL2Cl, trypletowych ekscymerów (PtL2Cl:PtL2Cl) i trypletowych ekscypleksów m-MTDATA (donor elektronu):PtL2Cl (akceptor elektronu), gdzie PtL2Cl oznacza organiczny kompleks platyny (II), a m-MTDATA - dendrymer aminowy. Kwantowa wydajność EL diody wynosi 6.5% fot./e. Współrzędne charakteryzujące...
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Narrow Red Emission Band Fluoride Phosphor KNaSiF6:Mn4+ for Warm White Light-Emitting Diodes
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Multi-Site Cation Control of Ultra-Broadband Near-Infrared Phosphors for Application in Light-Emitting Diodes
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Electromodulation of fluorescence in hole-transporting materials for organic light-emitting diodes. Part II: Straburst amines
PublicationPraca jest kontynuacją artykułu, który został opublikowany wChem. Phys. vol. 256 (2000) s. 351-362. Zaobserwowano silne wygaszenie fluorescencji w dendrymerach aminowych zbudowanych na bazie trifenyloaminy. Efekt ten został przypisany rozpadowi stanów emitujących światło pod działaniem silnego pola elektrycznego.
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Aluminate Red Phosphor in Light-Emitting Diodes: Theoretical Calculations, Charge Varieties, and High-Pressure Luminescence Analysis
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Penetrating Biological Tissue Using Light-Emitting Diodes with a Highly Efficient Near-Infrared ScBO3:Cr3+ Phosphor
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Ultra-Broadband Phosphors Converted Near-Infrared Light Emitting Diode with Efficient Radiant Power for Spectroscopy Applications
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High-electric-field quantum yield roll-off in efficient europium chelates-based light-emitting diodes
PublicationSkonstruowano dwuwarstwowe organiczne diody EL, w których warstwa transportująca dziury była domieszkowana organicznymi kompleksami europu. Maksymalna kwantowa wydajność świecenia takich diod osiągała w polu elektrycznym 1MV/cm wartość 5% foton/elektron. Wysokopolowy spadek kwantowej wydajności świecenia zinterpretowano na gruncie modelu Onsagera dysocjacji stanów emitujących.
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Exciton quenching in emitter blends for organic light emitting devices probed by electric field-dependent time-resolved luminescence
PublicationW pracy badano mechanizm wygaszania ekscytonów w układzie dwuamina TPD:organiczny kompleks Eu:matryca TPD przez pomiar zaniku fotoluminescencji w zewnętrznym polu elektrycznym.
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Highly efficient organic electrophosphorescent light-emitting diodes with a reduced quantum efficiency roll off at large current densities.
PublicationW pracy opisano diody elektrofosforescencyjne zbudowane na bazie organicznych komplesów platyny PtOEP oraz Pt(thpy)2. Pokazano, ze mechanizmem ograniczjącym wydajność świecenia tych diod w zakresiedużych prądów elektycznych jest elektrycznopolowa dysocjacja ekscytonutrypletowego z transferem dziury na molekułę TPD.
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Application of low-cost Gallium Arsenide light-emitting-diodes as kerma dosemeter and fluence monitor for high-energy neutrons
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Chemical Control of SrLi(Al1–xGax)3N4:Eu2+ Red Phosphors at Extreme Conditions for Application in Light-Emitting Diodes
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Controlling of Structural Ordering and Rigidity of β-SiAlON:Eu through Chemical Cosubstitution to Approach Narrow-Band-Emission for Light-Emitting Diodes Application
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Synthesis and structural, electrochemical and photophysical studies of triferrocenyl-substituted 1,3,5-triphenylbenzene: a cyan-light emitting molecule showing aggregation-induced enhanced emission
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Surface-Protected High-Efficiency Nanophosphors via Space-Limited Ship-in-a-Bottle Synthesis for Broadband Near-Infrared Mini-Light-Emitting Diodes
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Application of the Heavy-Atom Effect for (Sub)microsecond Thermally Activated Delayed Fluorescence and an All-Organic Light-Emitting Device with Low-Efficiency Roll-off
PublicationThefeatureof abundantandenvironmentallyfriendlyheavyatoms(HAs)like bromineto acceleratespin-forbiddentransitionsin organicmoleculeshas beenknownforyears.In combinationwiththe easinessof incorporation,brominederivativesof organicemittersshowingthermallyactivateddelayedfluorescence(TADF)emergeas a cheapand efficientsolutionforthe slowreverseintersystemcrossing(rISC)problemin suchemittersand strongefficiencyroll-offof all-organiclight-emittingdiodes(OLEDs).Here,we...
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Wideband Modeling of DC-DC Buck Converter with GaN Transistors
PublicationThe general wideband modeling method of the power converter is presented on the example of DC-DC buck converter with GaN High Electron Mobility Transistors (HEMT). The models of all basic and parasitic components are briefly described. The two methods of Printed Circuit Board (PCB) layout parameter extraction are presented. The results of simulation in Saber@Sketch simulation software and measurements are compared. Next, the model...
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Deep-Learning-Based Precise Characterization of Microwave Transistors Using Fully-Automated Regression Surrogates
PublicationAccurate models of scattering and noise parameters of transistors are instrumental in facilitating design procedures of microwave devices such as low-noise amplifiers. Yet, data-driven modeling of transistors is a challenging endeavor due to complex relationships between transistor characteristics and its designable parameters, biasing conditions, and frequency. Artificial neural network (ANN)-based methods, including deep learning...
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Morphology control via dual solvent crystallization for high-mobility functionalized pentacene-blend thin film transistors
PublicationWe present an approach to improving the performance of solution processed organic semiconductor transistors based on a dual solvent system. We here apply this to a blend containing the π-conjugated small molecule 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) and polystyrene, which acts as an inert binder. Using a semiconductor-binder solution of two solvents, where the main solvent is a better solvent of the small...
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Light box for investigation of characteristics of optoelectronics detectors
PublicationIn this paper, a light box for investigation of characteristics of optoelectronic detectors is described. The light box consists of an illumination device, an optical power sensor and a mechanical enclosure. The illumination device is based on four types of high-power light emitting diodes (LED): white light, red, green and blue. The illumination level can be varied for each LED independently by the driver and is measured by optical...
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Feasibility Study GaN Transistors Application in the Novel Split-Coils Inductive Power Transfer System with T-Type Inverter
PublicationA promising solution for inductive power transfer and wireless charging is presented on the basis of a single-phase three-level T-type Neutral Point Clamped GaN-based inverter with two coupled transmitting coils. The article focuses on the feasibility study of GaN transistor application in the wireless power transfer system based on the T-type inverter on the primary side. An analysis of power losses in the main components of the...
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Gate Driver with Overcurrent Protection Circuit for GaN Transistors
PublicationThe improvement of the gate driver for GaN transistor is presented in this paper. The proposed topology contains the overcurrent protectionwith the two-stage turning off and independent control of turn on and off time of the GaN transistor. The operation of driver and its application in thehalf-bridge converter are described using both simulation and prototype measurements. The overcurrent protection was tested in Double Pulse...
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Games and play with light in architecture
PublicationThe paper deals with the issue of the influence of daylight on the creation of architecture in the view of designers` play with light in the architectural space. Using the examples of contemporary realizations of some art museums, the work demonstrates the impact of exploration and experimentation conducted by the creators of visual arts on the design styles and architectural solutions. It also reveals the historical continuity...
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Protect our right to light
Publication“The struggle for light” is how the Swiss architect Le Corbusier described the history of architecture in 1935. Today, with the skies crowded out by buildings in modern cities, those words should ring in the ears of policymakers and planners. Skyscraper construction is booming. China is the leader, last year completing 88 of the 143 buildings around the world that are taller than 200 metres (see ‘Vertical growth’). As the nation’s...
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Efficient exciplex emitting organic electroluminescent devices
PublicationW pracy badano stany wzbudzenia elektronowego, powstające z udziałem dwóch molekuł. Dzięki doborowi odpowiednich materiałów na warstwę przewodzącą dziury (pochodna trójfenyloaminy: m-MTDATA) i elektronów (pochodna oksadia-zolu:PBD) w cienkowarstwowej diodzie EL stworzono szczególnie dogodne warunki do generacji ekscypleksów (M-MTDATA-PBD) i wysokowydajnej (>1% foton/e-lektron) emisji ekscypleksowej.
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The PWM current source inverter with IGBT transistors and multiscalar model control system
PublicationW niniejszym artykule przedstawiono struktury układów sterowania maszyny indukcyjnej zasilanej z falownika prądu. Przedstawiono metodę modulacji szerokości impulsów dla falownika prądu. Pokazano modele matematyczne maszyny indukcyjnej klatkowej zasilanej z falownika prądu. Przedstawiono trzy układy regulacji sterowania multiskalarnego z czego dwa są nowe. Rozważania teoretyczne zweryfikowano za pomocą badań symulacyjnych.
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LIGHT POLLUTION IN THE CONTEXT OF THREATS TO THE WILDLIFE CORRIDORS
PublicationAccess to remote sensing night-time imagery allows for modeling of light pollution Increasingly, data on the propagation of artificial light are a source of interesting information for different fields of science and affect the planning of economic development. The article presents the problem of light pollution in the context of threats to the wildlife corridors in Poland. Wildlife corridors are areas that allow safe migration...
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LED Light Sources and Their Complex Set-Up for Visually and Biologically Effective Illumination for Ornamental Indoor Plants
PublicationOrnamental plants are often used in indoor environments as part of biophilic design to improve the health and wellbeing of occupants, and to support sustainable, green architecture. Unfortunately, many plants do not thrive and need to be continuously replaced, which is economically unsustainable. The wavelengths and spectrum ratio of commonly used light sources such as light emitting diode (LED), and the lack of an appropriate...
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Organic Vapor Sensing Mechanisms by Large-Area Graphene Back-Gated Field-Effect Transistors under UV Irradiation
PublicationThe gas sensing properties of graphene back-gated field-effect transistor (GFET) sensors toward acetonitrile, tetrahydrofuran, and chloroform vapors were investigated with the focus on unfolding possible gas detection mechanisms. The FET configuration of the sensor device enabled gate voltage tuning for enhanced measurements of changes in DC electrical characteristics. Electrical measurements were combined with a fluctuation-enhanced...