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1

C,N-cyklometalowane kompleksy irydu(III) : wydajne emitery fosforescencyjne dla organicznych diod elektroluminescencyjnych (OLED). Cz. 1 i 2

Orwat Bartosz, Kownacki Ireneusz

Wiadomości Chemiczne

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2021

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[Z] 75, 1-2

163--231

EN

Organic electroluminescent panels have been widely available on the commercial market for several years, in the form of screens used in mobile phones, tablets, and TV sets. The display panels are produced in RGB technology, in which iridium(III) coordination compounds act as phosphorescent emitters of red and green light. Because of their high emission quantum efficiency and stability, the emitters containing 2-phenylpyridinato ligands and their derivatives have proved to be particularly useful. An interesting issue was the contrast between an extensive state of knowledge on the abovementioned compounds and a poor state of knowledge on analogous iridium(III) complexes equipped with benzo[h]quinolinato ligands. Application of the latter seemed interesting because of the similar size of benzo[h]quinoline and 2-phenylpyridine coordination pockets, but much more rigid structure and a greater degree of conjugation of the former, which could have a significant impact on the properties of complexes equipped with this type of ligand. Regarding to the above, this dissertation concerns the subject of the design and synthesis of new iridium(III) coordination compounds equipped with a benzo[h]quinoline motif, as well as the analysis of the structural changes impact on the photophysical, electroluminescent, thermal, electrochemical and spectroscopic properties of selected classes of compounds targeted for the application in OLED technology. Accordingly, the article presents the results of studies on two classes of heteroleptic of C,N-cyclometalated iridium(III) complexes, namely, of the salt type with the general formula [Ir(bzq)2(N^N)]+A-, stabilized by structurally different N,N-donating ligands, as well as neutral coordination compounds of the type [Ir(bzq)2(N^O)], bearing N,O-donating ß-ketoiminato ligands in the structure equipped with aryl moieties of various structure. The work included research on the determination of the correlation between the structure of ancillary ligand introduced into the coordination sphere of the metal and the above-mentioned properties. Additionally, based on the results of quantum-chemical calculations, work was undertaken to develop synthetic pathways enabling the incorporation to the C,N-cyclometalating benzo[h]quinoline ligand of substituents characterized by different stereo-electronic properties, enabling the modification of the emission parameters of the target complexes. In the next phase of research, the functionalized precursors of the bzq ligand were successfully used in the synthesis of binuclear complexes, key reagents in the preparation of corresponding mononuclear iridium coordination derivatives with electroluminescent properties.

2

Numerical analysis of the compositional graded quaternary barrier AlGaN-based ultraviolet-C light-emitting diode

Malik S., Usman Muhammad, Hussain M., Munsif M., Khan S., Rasheed S., Ali S.

Opto-Electronics Review

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2021

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Vol. 29, No. 3

80--84

EN

The compositional graded quaternary barriers (GQBs) instead of ternary/conventional quantum barriers (QBs) have been used to numerically enhance the efficiency of AlGaN-based ultraviolet light-emitting diode (LED). The performance of LED with GQBs is examined through carrier concentrations, energy band diagrams, radiative recombination, electron and hole flux, internal quantum efficiency (IQE), and emission spectrum. As a function of the operating current density, a considerable reduction in efficiency droop is observed in the device with composition-graded quaternary barriers as compared to the conventional structure. The efficiency droop in case of a conventional LED is ~77% which decreased to ~33% in case of the proposed structure. Moreover, the concentration of electrons and holes across the active region in case of the proposed structure is increased to ~156% and ~44%, respectively.

3

Structure equation as novel strategy for optimum reflector design

Ou Chung-Jen

Optica Applicata

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2020

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Vol. 50, nr 1

95--110

EN

The optimal use of energy resources is the central dogma for green technology and bio-optics. Reflectors provide a simple and fundamental structure for energy transport from a light emitting diode (LED) chip, and an appropriately designed reflector can reduce the fabrication cost of secondary optics for the LED. This paper demonstrates the role of three proposed reflector geometric factors in the two performance metrics – uniformity and collected energy (power), for designing LED reflectors. Through canonical factor analysis, a linear structure equation for LED reflector is suggested, and the methodology for designing the optimal shape is discussed. In addition, a generalized factor and a synthesis response are proposed for a more comprehensive investigation of optical performance. Results indicate a key parameter for balancing the optical performance, and the effects of various parameters and the trade-offs are revealed.

4

Design of LED collimator for uniform illumination using two freeform lenses

Zeng J., Li X., Ge P.

Optica Applicata

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2018

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Vol. 48, nr 3

413--420

EN

Regulating the illuminance distribution of an LED collimator to produce a uniform illumination in both the near field and the far field is a challenge in illumination design. In this paper, we present an effective method for designing two separated freeform lenses to control the illuminance distribution and the direction of the rays from the LED. The first lens redistributes the ray energy, and the second one collimates them to obtain a uniform collimated illumination. According to the conservation law of energy, Snell’s law, Fermat’s law and tangent-plane iterative method, the two freeform surfaces could be calculated simultaneously. The simulation results show that the two freeform lenses can control most of rays into an angle within ±1.5° for an LED with 1 × 1 mm size. The illuminance uniformities are higher than 0.9 in both the near field and the far field.

5

The Effect of Light-Emitting Diodes Illumination Period and Light Intensity on High Rate Algal Reactor System in Laundry Wastewater Treatment

Tangahu B. V., Triatmojo A., Purwanti I. F., Kurniawan S. B.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 6

170--175

EN

Wastewater that contains high concentration of nutrients can create instability in water ecosystem if left untreated. Laundry wastewater contains nutrients in high concentration. The nutrients that commonly found in laundry wastewater are nitrogen and phosphorus. This study had a purpose to determine the effect of illumination period and light intensity for the removal of Chemical Oxygen Demand (COD), Nitrogen-ammonia (NH3-N), and phosphate (P) content using Chlorella vulgaris in High Rate Algal Reactor (HRAR) treatment. Variables that used were exposure period of 12 and 24 hours and light intensity of 2000–3000 Lux, 4000–5000 Lux, and 6000–7000 lux. The parameters tested to determine the efficiency of nutrient removal were COD, Nitrogen-ammonia, phosphate and Chlorophyll α to determine the condition of algae development. The results showed that the highest nutrient removal were obtained by the reactor with 24 hours illumination period with light intensity of 6000–7000 Lux that was capable of removing 54.63% of COD, and 22.15% of P. The 12-hour illumination period was better in terms of NH3-N removal, up to 50.07%. On the basis of the of statistic test result, the illumination period did not significantly influence the removal efficiency of COD, NH3-N and P indicated by P-value >0.05, while the light intensity significantly affect the removal of COD and NH3-N showed by P value <0.05.

6

Ukorzenianie sadzonek chryzantemy wielkokwiatowej z zastosowaniem diod elektroluminescencyjnych

Woźny A., Rymarz D.

Polish Journal for Sustainable Development

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2017

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T. 21, cz. 2

153--160

PL

Doświetlanie upraw jest powszechnie wykorzystywane do poprawy plonowania i jakości roślin ozdobnych. Diody to obiecujące rozwiązania technologiczne, których liczne zalety przewyższają tradycyjnie stosowane lampy sodowe. W produkcji chryzantem szczególnie istotne jest pozyskanie prawidłowo wykształconych i dobrze ukorzenionych sadzonek. W całorocznej uprawie sterowanej konieczne jest doświetlanie sadzonek ukorzenianych od listopada do połowy lutego. W przeprowadzonym doświadczeniu badano możliwość zastosowania światła emitowanego przez diody w trakcie ukorzeniania sadzonek trzech odmian chryzantemy wielkokwiatowej. Wykazano, iż lampy do doświetlania roślin zbudowane w technologii LED mogą z powodzeniem zastąpić lampy sodowe (HPS) jako dodatkowe źródło światła na etapie ukorzeniania sadzonek. Mniejsze zużycie energii w porównaniu z konwencjonalnymi lampami sodowymi z pewnością zwiększy opłacalność całorocznej produkcji chryzantem.

EN

Supplementary lighting is commonly used to increase yield and quality of ornamental plants. Light – emitting diodes (LEDs) represent a promising technology for the greenhouse industry that has technical advantages over traditional sodium lamps. In the production of chrysanthemums it is particularly important to have properly developed and well-rooted cuttings. In year – round controlled cultivation of chrysanthemums it is necessary to use supplementary lighting from November to mid-February. The possibility of application of LED during the rooting of two cultivars of chrysanthemums was investigated. Our data suggest that LEDs are suitable replacements for HPS lamps as supplemental light sources during the cuttings rooting. Lower energy consumption compared to conventional sodium lamps will increase the profitability of year – round controlled production of chrysanthemums.

7

Spectrally tunable light source based on light-emitting diodes for custom lighting solutions

Burgos-Fernandez F. J., Vilaseca M., Perales E., Herrera-Ramirez J. A., Martinez-Verdu F. M., Pujol J.

Optica Applicata

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2016

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Vol. 46, nr 1

117--129

EN

This study describes a novel spectral LED-based tunable light source used for customized lighting solutions, especially for the reconstruction of CIE (Commission Internationale de l'Eclairage) standard illuminants. The light source comprises 31 spectral bands ranging from 400 to 700 nm, an integrating cube and a control board with a 16-bit resolution. A minimization algorithm to calculate the weighting values for each channel was applied to reproduce illuminants with precision. The differences in spectral fitting and colorimetric parameters showed that the reconstructed spectra were comparable to the standard, especially for the D65, D50, A and E illuminants. Accurate results were also obtained for illuminants with narrow peaks such as fluorescents (F2 and F11) and a high-pressure sodium lamp (HP1). In conclusion, the developed spectral LED-based light source and the minimization algorithm are able to reproduce any CIE standard illuminants with a high spectral and colorimetric accuracy able to advance available custom lighting systems useful in the industry and other fields such as museum lighting.

8

Thermal resistance of GaAs/AlAs superlattices used in modern light-emitting diodes

Żak D., Nakwaski W.

Opto-Electronics Review

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2014

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Vol. 22, No. 2

86-91

EN

Superlattices are used in modern light-emitting diodes to modify intentionally electron, phonon and/or photon transport within their volumes, which leads to their expected performance characteristics. In particular, superlattices may have a dramatic impact on device thermal properties. Superlattice thermal resistance is anisotropic and usually distinctly higher than its values in constituent bulk materials, which results from phonon reflections and/or phonon scatterings at numerous layer interfaces. In the present paper, thermal resistance of a typical superlattice of layer thicknesses neither much higher nor much lower than the phonon free path is discussed. Besides, as an important example, thermal resistance of the typical GaAs/AlAs superlattice is determined theoretically and compared with its measured values known from literature.

9

Diody LED - odpady niebezpieczne dla środowiska

Sokołowska W., Karaś A., Zalewska I., Harasimowicz-Siemko J.

Materiały Elektroniczne

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2011

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T. 39, nr 2

23-26

PL

W Laboratorium Charakteryzacji Materiałów Wysokiej Czystości ITME przeprowadzono analizę składu chemicznego kilku rodzajów diod LED obecnych na polskim rynku [2]. Omówiono zawartość metali kancerogennych oraz metali niebezpiecznych dla środowiska . Porównano je z rezultatami uzyskanymi w UCI (Uniwersytet Kalifornia) opisanymi w [1] i normami TTCL.

EN

An analysis of the chemical composition of several types of light-emitting diodes available on the Polish market was conducted in the Department of High Purity Materials Characterization of ITME [2]. In the course of the analysis, the content of carcinogenic metals and environmentally hazardous metals was explored. The findings were compared with the results achieved at the University of California, Irvine, described in [1], and with TTCL standards.

10

Opportunities to apply LED RGB systems in lighting

Wiśniewski A.

Przegląd Elektrotechniczny

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2008

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R. 84, nr 8

178-181

EN

This paper presents some selected types of light-emitting RGB diodes and the opportunities to produce white colour of light. Study results on the opportunities to use the RGB diodes emitting white colour of light in lighting are presented too.

PL

Artykuł prezentuje wybrane typy diod elektroluminescencyjnych systemu RGB i możliwości wytwarzania światła barwy białej. W artykule zawarta jest analiza możliwości zastosowania diod RGB wytwarzających białe światło w oświetleniu.

11

Epoxy-carbazole compositions. Part I. Compositions with 9-(2, 3-epoxypropyl) carbazole

Czub P., Mazela W., Pielichowski J.

Polimery

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2003

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T. 48, nr 9

641-644

EN

Compositions of low-molecular weight epoxy resin Ruetapox 0162 mixed with various amounts of 9-(2,3-epoxypropyl)carbazole (EPK) have been prepared and cured by isophorone diamine. Mechanical, thermal and photoluminescence properties of obtained materials were determined. It was found that low- molecular weight epoxy resin is an excellent dispersing matrix for carbazole groups, which secures suitable mechanical properties, low combustibility and high thermal stability of prepared materials. Moreover, it was observed that the addition of 10 wt. % of EPK improves compression strength by 15%, flexural strength by 33% and also slightly decreases water absorption. Thin film forming ability and optic properties, characteristic for isolated carbazole molecules (photoluminescence maxima at 352 and 368 nm), point at the possibility to use studied materials for light-emitting diodes (LED) construction.

PL

W wyniku mechanicznego zmieszania otrzymano jednorodne kompozycje małocząsteczkowej żywicy epoksydowej (diglicydy-lowego eteru bisfenolu A) o różnej zawartości (5, 10 i 15% mas.) 9-(2,3-epoksypropylo)karbazolu (EPK). Kompozycje te następnie sieciowano izoforonodiaminą i badano ich właściwości mechaniczne, termiczne oraz fotoluminescencyjne. Stwierdzono, że malocząsteczkowa żywica epoksydowa doskonale spełnia rolę matrycy rozpraszającej grupy karbazolowc, co nadaje otrzymanym materiałom korzystną charakterystykę mechaniczną, małą palność i dużą odporność termiczną (tab. 1 i 2). Optymalne właściwości wykazują kompozycje zawierające 10% mas. EPK. Łatwość formowania cienkich warstw oraz właściwości optyczne charakterystyczne dla izolowanych cząsteczek karbazolu (z maksimami fotoluminescencji przy 353 i 368 nm) (rys. 2) wskazują na możliwość zastosowania badanych kompozycji jako materiałów do konstrukcji diod świecących.

12

Zastosowanie laserów półprzewodnikowych w systemach telekomunikacji multimedialnej

Korzec Z., Kacprzak T.

Elektronika : prace naukowe

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2001

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nr 6

31-49

PL

Stały wzrost zapotrzebowania na przekazywanie informacji na dowolne odległości, w krótkim czasie, wymusza powstawanie nowych technik ich przetwarzania, wysyłania i odbioru. W ostatnich latach wykorzystanie najnowszych osiągnięć w dziedzinie technologii laserów półprzewodnikowych, w powiązaniu z liniami światłowodowymi i nowymi metodami zwielokrotniania w dziedzinie długości fal, pozwoliło na przenoszenie informacji w liniach światłowodowych zarówno na małe, średnie, jak i duże odległości z niemożliwą do zrealizowania w innych systemach prędkością - rzędu terabitów na sekundę. W artykule omówiony został rozwój laserów półprzewodnikowych i przedstawione zostały ich najnowsze rozwiązania technologiczne.

EN

Recently optical networks are growing at unprecedented rates to satisfy the urgent demands in data traffic, and an associated tremendous bandwidth request made by users, brought on by new telecommunication and multimedia services. Photonics, the technology of using particles of light as information carriers, takes the first place in the telecommunication systems because of the advantage of optical fiber over coper cable for data communication. Optical fibers are capable of carrying data at rates exceeding terabits per second at distances even of thousands of kilometers. Initially, as the main light source light emitty diode was mainly used. But now, as data rates increased, communication system make special demands on optical sources. The light source for optical data transmission must be small, efficient, capable of high speed modulation and must have controllable pattern of emissions in the optimum wavelength windows for silica fiber or in shorter-wavelength ranges for free-space interconnections. These requests can be fulfilled only by semiconductor injection laser. Nowadays this device can be manufactured inexpensively in large volumes and can easily interface with other circuitry, preferably silicon based. It can be diced either individually or in arrays that are easily coupled to optical fibers. This paper reviews recent progress in semiconductor lasers technology with emphasis on their application in optical telecommunication systems. Semiconductor injection lasers were first developed in 1962, but it was not until 1970 that a potentially practical device was demonstrated. The key moment in their development was the invention of the double heterostructure (DH- laser). The most important advantage of the DH laser is that it concentrates carriers in a very small region, thus a carrier density high enough to support laser oscillation can be achieved with a relatively low drive current. The next very important step is development of distributed-feedback laser and vertical-cavity, surface-emitting laser (VCSEL). These low-cost, nearly ideal sources are changing the attitudes tower modern optical communications.