Top Light Research Articles

Optimization of the Design of a Greenhouse LED Luminaire with Immersion Cooling

Modern agriculture, with the use of artificial lighting, requires high-intensity LED luminaires with compact dimensions. In this regard, new approaches to the design of LED luminaires using both new materials and technical solutions have been considered. The theoretical evaluation of the influence of different materials on the efficiency of removal of thermal energy from LEDs was shown. A new material PMS-5 is proposed and evaluated as an immersion liquid, which can be used as an effective heat sink in the lower part of the luminaire up to the level of LEDs located in the top light LED luminaires. The proposed polymethylsiloxane PMS-5 liquid has more than twice the thermal conductivity (0.167 W/(m·K)) of HFE7200 and NS15 liquids used in immersion-cooled LED luminaires. Based on the theoretical evaluation, the requirements for parameters, such as metal profile area, immersion liquid volume, wall thickness area, and external area of the cylinder, are highlighted and shown. The noted parameters have a key role in the design of an efficient top light LED luminaire. It has been shown that the design of the metal profile significantly affects the efficiency of the removal of thermal energy from LEDs and it is necessary to use specialized profiles optimized for the diameter of the LED luminaire cylinder. A number of LED luminaire designs were proposed, depending on the thermal properties of the construction materials, technical and economic performance, as well as actual operating and installation conditions. The analysis of the presented theoretical evaluations allowed overlay of the design basis of LED luminaires within the presented concept and top light.

Two-Dimensional Janus XY (X/Y=P, As, Sb, Bi, X≠Y) material with excellent piezoelectricity and carrier mobility for Visible-Light water splitting

Janus materials, with unique physical and chemical properties, show promise in turning solar energy into clean hydrogen through photocatalytic water splitting. Herein, utilizing first-principles calculations, we have confirmed the stabilities of newly discovered two-dimensional XY materials (X/Y=P, As, Sb, Bi, X≠Y), unveiling their promising capabilities in photocatalytic water splitting. These Janus structures exhibit broad bandgaps, paired with remarkable electron carrier mobilities. Their out-of-plane piezoelectric coefficients (d31) varying from 0.10 pm/V to 0.31 pm/V, surpass those of many typical two-dimensional materials, highlighting their considerable potential in energy conversion applications. These materials stand out in water splitting due to their favorable band edges and electrostatic potential gradients, achieving solar-to-hydrogen (STH) efficiencies above 20 % and visible light absorption efficiencies over 10 %. Remarkably, Janus PBi showcases STH and visible light absorption efficiencies up to 29.01 % and 19.33 %, respectively. By using biaxial strain, Janus PAs and PSb can reach a peak STH efficiency of over 30 % and a top visible light absorption efficiency above 20 %. Janus AsSb (PBi) exhibits exceptionally high photocatalytic activity for the oxygen (hydrogen) evolution reaction. These attributes suggest that these Janus XY materials are promising contenders as photocatalytic catalysts for water-splitting applications.

95‐3: Fabrication of Sub‐Micron Organic/Inorganic Hybrid Thin‐Film Encapsulation on Ultra‐High‐Resolution Microdisplays Using Inkjet Printing Process.

In this study, we fabricated sub‐micron organic/inorganic hybrid TFE (Thin Film Encapsulation). We utilize an inkjet printing process to fabricate organic layer. It has excellent industrial applicability by using an industrial printhead with 1024 nozzles. The thickness of the organic layer is optimized through the DPI (Drops Per Inch) of inkjet printing and surface treatment of substrate. The sub‐micron organic/inorganic hybrid TFE was fabricated on a TEOLED (Top Emission Organic Light Emitting Diode), and the OLED (Organic Light Emitting Diode) with the fabricated TFE did not show degradation. Under constant temperature and humidity conditions 30°C, 90 % R.H. (Relative Humidity), the luminance of the OLED remained the same without any defects. The fabricated TFE for the production of OLEDoS has excellent encapsulation properties even at a thin thickness. Finally, we are investigating the optical properties of the ultra‐high‐resolution microdisplay panel applied with the sub‐micron organic/inorganic hybrid TFE.

P‐29: A bias TFT with high photosensitive current for optical sensors

A photosensitive TFT sensor called bias TFT fabricated using simple amorphous silicon process in this paper. The photosensitive current of bias TFT is linearly related to the brightness of the top light source and inversely proportional to the size of the bias region. The photosensitivity current can be up to 10E‐8 amperes under 100 nits illumination. Among four shapes of bias TFTs, L‐type TFTs have the highest photo current.

Consecutive Pruning Enhances Leaf Flavonoids, Leaf Yield, and Cutting Rooting in Ginkgo biloba

Ginkgo biloba L. is a valuable medicinal plant known for its high content of flavonoids and terpenoids in the leaves of young trees. Pruning can increase leaf yield in ginkgo plantations; however, it is unclear how the intensity of pruning affects leaf yield and quality. In addition, G. biloba exhibits low cutting rooting rates, which limits its efficiency in asexual propagation. In our study, we compared consecutive pruning with varying levels of intensity, including top pruning, light pruning, and heavy pruning, to evaluate the effects of pruning on leaf yield and cutting rooting. The results showed that these three pruning methods all contributed to an increase in the number of new branches, the leaf weight, and the flavonoid content in five-year-old trees. Among them, the effect of light pruning was the best, with a 150% increase in branch number, a 130% increase in leaf weight, and a 40.6% increase in flavonoid content. The secondary pruning further increased leaf area by 22.3%, indicating that secondary pruning further enhanced the rejuvenation of plants and increased leaf yield. At the transcriptional level, pruning can significantly change the expression of genes related to bud sprouting, resulting in a particularly significant increase in SHR expression in the buds. Pruning also promoted the expression of important genes related to flavonoid synthesis, including chalcone synthase (CHS), flavonoid 3′-hydroxylase (F3′H), flavonol synthase (FLS), and dihydroflavonol reductase (DFR). Furthermore, we demonstrated a significant increase in the rooting rate of these second-pruned branch cuttings and screened the optimal hormone ratio for rooting, which is 1.5 μM MeJA + 400 mg/L NAA + 100 mg/L Uniconazole-P. These results suggest that secondary pruning can effectively rejuvenate plants to promote cutting rooting in G. biloba. This method can not only be used to improve the yield and quality of ginkgo leaves, but also for cutting propagation.

Selectively Modulating Componential Morphologies of Bulk Heterojunction Organic Solar Cells.

Achieving precise control over the nanoscale morphology of bulk heterojunction films presents a significant challenge for the conventional post-treatments employed in organic solar cells (OSCs). In this study, a near-infrared photon-assisted annealing (NPA) strategy is developed for fabricating high-performance OSCs under mild processing conditions. It is revealed a top NIR light illumination, together with the bottom heating, enables the selective tuning of the molecular arrangement and assembly of narrow bandgap acceptors in polymer networks to achieve optimal morphologies, as well as the acceptor-rich top surface of active layers. The derived OSCs exhibit a remarkable power conversion efficiency (PCE) of 19.25%, representing one of the highest PCEs for the reported binary OSCs so far. Moreover, via the NPA strategy, it has succeeded in accessing top-illuminated flexible OSCs using thermolabile polyethylene terephthalate from mineral water bottles, displaying excellent mechanical stabilities. Overall, this work will hold the potential to develop organic solar cells under mild processing with various substrates.

Dampak Bukaan Cahaya Alami Bagian Atas terhadap Kenyamanan Visual dan Termal Rumah Tinggal Dempet

<p><em>Housing is one of the 3 primary human needs, namely clothing, food and shelter. The development of residential houses is growing rapidly with various types, one of which is a couple or attached type of residence developed by housing developers. Couple residences generally do not have side openings and only use natural light sources from the front and back of the house. These problems make the owner make a solution for opening the upper natural lighting with the aim of optimizing the entry of sunlight during the day so that there is no need for additional energy to illuminate the room. The next problem from the application of top light openings is that the light consumed by the space will be excessive and cause heat in the space. This research method is measuring the value of incoming light using a lux meter and measuring temperature and heat envelopes using a thermal camera with the hope that the measurement results are able to create the right top light opening so that it does not cause glare and does not increase heat in the room.</em></p>

Additive effects of light and branching on fruit size and chemical fruit quality of greenhouse tomatoes.

Greenhouse tomato growers face the challenge of balancing fruit size and chemical quality traits. This study focused on elucidating the interplay between plant branching and light management on these traits, while maintaining consistent shoot density. We evaluated one- and two-shoot plants under varying top light intensities using high-pressure sodium lamps and light-emitting diode (LED) inter-lighting. The reduced yield in the two-shoot plants was mainly due to smaller fruit size, but not due to source strength limitations, as evaluated through leaf weight ratio (LWR), chlorophyll index, specific leaf area (SLA), leaf dry matter percentage, and stem soluble carbohydrate accumulation. Enhanced lighting improved fruit weight and various fruit traits, such as dry matter content, total soluble carbohydrate content, and phenolic content, for both one- and two-shoot plant types. Despite lower mean fruit weight, two-shoot plants exhibited higher values for chemical fruit quality traits, indicating that the fruit growth of two-shoot plants is not limited by the available carbohydrates (source strength), but by the fruit sink strength. Diurnal analysis of fruit growth showed that two-shoot plants had reduced expansion during light transitions. This drop in fruit expansion was not related to changes in root pressure (measured as xylem sap exudation from decapitated plants), but might be related to diminished xylem area in the stem joint of the two-shoot plants. The concentration of several hormones, including cytokinins, was lower in two-shoot plants, suggesting a reduced fruit sink capacity. The predominant impact of branching to two-shoot plants on sink capacity suggests that the fruit growth is not limited by available carbohydrates (source strength). Alongside the observation that light supplementation and branching exert independent additive effects on fruit size and chemical traits, this illuminates the potential to independently regulate these aspects in greenhouse tomato production.

High performance red and green phosphorescent emitters suitable for the BT.2020 color gamut

AbstractIn this work, we investigated the potential for phosphorescent emitters to achieve the BT.2020 color standard in displays, where the CIE coordinates for red and green are (0.709, 0.292) and (0.170, 0.797), respectively. Optical simulations were performed for both green and red top emission organic light emitting devices (OLEDs). For the green emitter, it is possible to reach (0.170, 0.785) using a spectrum with a peak wavelength (λmax) at 526 nm and a full width at half maximum (FWHM) less than 30 nm. For the red emitter, in order to achieve (0.708, 0.292) while maintaining a high current efficiency (CE), it is important to decrease the FWHM instead of red‐shifting the spectrum. Following the guidance of these simulation results, we designed and synthesized novel deep green (DGD) and deep red phosphorescent (DRD‐II) emitters. The photoluminescent (PL) spectrum of DGD shows an FWHM of 30 nm and a λmax of 523 nm. A top‐emission green OLED built using DGD reached a CE of 171 cd/A at an operating voltage of 3.3 V and a lifetime of 95% of initial brightness (LT95) > 1300 h at 10 mA/cm2 with a CIE (x, y) = (0.170, 0.777). This is, to our knowledge, the best device performance ever reported for a green phosphorescent OLED at this CIE y. The PL spectrum of DRD‐II has a λmax of 630 nm with an FWHM of 30 nm. A top‐emission red OLED built with DRD‐II achieved a CE of 59 cd/A, an operating voltage of 3.2 V and an LT95 over 20,000 h at a drive current of 10 mA/cm2 with a CIE (x, y) = (0.708, 0.292). We also studied the angular dependence of the above devices and found they were comparable to devices with commercial emitters for the Digital Cinema Initiative P3 (DCI‐P3) standard that had a wider FWHM. Combining these green and red emitters with a commercial blue OLED at (0.131, 0.046), we are able to cover 97% of the BT.2020 color gamut. The results using DGD and DRD‐II suggest that they have great potential to satisfy BT.2020 in an organic phosphorescent system.

18.3: Invited Paper: Efficiency Enhanced Top‐Emitting Organic Light‐Emitting Diodes Comprising Micro‐lens Array

We report a highly enhanced light extraction from a top emission organic light emitting diode with little image blurring. Integration of a high refractive index micro lens array on the top of the transparent indium zinc oxide top electrode of a green and blue OLED shows a significant EQE gain of 16% and 8%, respectively.

First discovery of quasi-periodic oscillations in the dwarf nova HS 2325+8205 based on TESS photometry

ABSTRACT HS 2325+8205 is a long-period eclipsing dwarf nova with an orbital period above the period gap (Porb > 3 h) and is reported to be a Z Cam-type dwarf nova. We study the light variation and the quasi-periodic oscillations (QPOs) of HS 2325+8205 based on the photometry of theTransiting Exoplanet Survey Satellite (TESS). Using a continuous wavelet transform, a Lomb–Scargle periodogram (LSP), and sine fitting methods, we find for the first time that there is a QPO of ∼2160 s in the long outburst top light curves of HS 2325+8205. Moreover, we find that the oscillation intensity of the QPOs of HS 2325+8205 is related to the orbital phase, and the intensity in orbital phases 0.5–0.9 is stronger than in orbital phases 0.1–0.5. Therefore, the relationship between the oscillation intensity of QPOs and the orbital phase may become a topic of research into the origin of QPOs. In addition, we use the LSP to correct the orbital period of HS 2325+8205 to 0.19433475(6) d.

Merits of narrow spectral blue fluorescence emitters in strong micro-cavity top emission OLEDs

The top emission organic light emitting diode (TEOLED) structure can realize the high efficiency and high color purity through the micro-cavity effect. The characteristics of TEOLED are enhanced by improving the electrodes structures or designing cavities through organic layers. Apart from these factors, the optical characteristic of the emitting material is another very important aspect to improve the TEOLED characteristics. In the present study, we investigated the influence of the narrow full width at half maximum (FWHM) of emitter on the blue light emitting device characteristics through the simulations and experiments. We analyzed the radiance, current efficiency, and blue index characteristics of TEOLED using several emitters having different FWHM values. As the FWHM became narrower, the radiant out-coupling spectrum could overlap sufficiently with original one; so the radiance was improved, but the current efficiency was affected due to the decrease in luminosity factor. Additionally, the blue index value is an important in TEOLED structure, as display applications uses it. TEOLED having the same emission peak value, the narrower FWHM emitter is advantageous in terms of the blue index because of the improved color purity. The narrower the FWHM, the just noticeable color difference is low. The color stability according to the viewing angle is also improved. From the optical simulation results, the optimum condition of the emitter FWHM varies from 14 to 16 nm and the emission peak shifts from 460 to 462 nm. With these emitter conditions, the TEOLED device has excellent color purities and the highest blue efficiency characteristics. • Analyzes the efficiency of TEOLED device according to the FWHM of the blue emitter. • Efficiency is analyzed through optical simulation. • The viewing angle characteristics in terms of the FWHM of the blue emitter were also observed. • In order to obtain a TEOLED device with outstanding characteristics, we suggest the optimal conditions of wavelength and FWHM of blue emitter.

The effect of underwater supplemental light on the growth of V.spinulosa Yan and the restoration process of water

Submerged plants are often used in the ecological restoration of polluted water, and they have good water purifying effect. In the process of water restoration, submerged plants are faced with insufficient light due to high turbidity or water depth. Therefore, we proposed a new model of artificial light assisted submerged plants to purify water nutrients. In this paper, we investigated the effects of locations and light intensities on the growth of V.spinulosa Yan and its water purification effect. The results showed that the light location of the underwater supplemental light was more important than the light intensity. The top supplemental light may provide an excellent environment for algae on the water surface. Excessive algae or epiphytic microorganisms might prevent the V.spinulosa Yan from obtaining light. When the PAR= 109 μmol m−2 s−1, V.spinulosa Yan had a higher biomass (145.39 dw/m2) than before (65.2 dw/m2). When the PAR > 280 μmol m−2 s−1, the clonal reproduction of V.spinulosa Yan was reduced. The main effect of supplemental underwater light on the water restoration process was enhancing the photosynthesis of V.spinulosa Yan by changing ETRmax and Fv/Fm of V.spinulosa Yan leaves. It significantly increased V.spinulosa Yan biomass and improved dissolved oxygen. Improvement of the water environment possibly altered the microbial environment and promoted the removal of water nutrients.

(Invited) Organic Dyes Derived from Molecules in Cacao Beans for Use in Lighting Applications

LEDs are the foundation of lighting and display products surrounding us. While they have obtained great success in the commercial market, related research and development activities remain highly active aiming to enhance factors such as energy efficiency, stability, and environmental sustainability. Currently, commercial LED products are comprised of two key components: an indium gallium nitride e LED backlight with emission centered at 450 nm to cover the blue region of the visible spectrum, and powder inorganic phosphors on top converting blue light into longer wavelengths (e.g., green and red) to tune the emission of the device. A drawback of inorganic phosphors is that scattering of the emission from the micron-sized phosphor powders leads to substantial backscattering and subsequent absorption of the emission into the LED chip, and reabsorption losses in the phosphor itself, both of which reduce the overall light output of the final LED device. Organic dyes possess environmental advantages over inorganic phosphors because they are pi-conjugated molecules made from abundant elements (C, H, N, O, etc.) and are potentially bio-sourced. In this talk, I will present dyes that have been developed from theobromine, derived from cacao beans. When blended within an industrial polymer, poly(styrene-butadiene-styrene) (SBS), their enhanced solubility enables the formation of highly transparent films, crucial for reducing scattering loss in LEDs. Furthermore, resultant dye-SBS films achieved photoluminescence quantum yields (PLQYs) of around 90% under ambient conditions. Taking advantage of their transparency and solution processability, we fabricated a waveguide with this theobromine-dye-SBS composite, which was subsequentially assembled into an edge-lit LED device of no glare and enhanced aesthetics.

LIGHT IN THE SACRED SPACE OF THE MODERN GREEK CATHOLIC CHURCHS

Based on domestic and foreign experience, an analysis of the natural light filling of the sacred space of Modern Greek Catholic churches in Ukraine and abroad. Similarities and differences in the formation of the light environment of the modern church, compared with the traditional one, have been establish. The architecture of Modern Greek Catholic churches in Ukraine significantly influenced by the traditions of architectural formation of other branches of Christianity. This influence manifested primarily in the organization of their lighting environment. In Modern Greek Catholic churches, there is a top light from the domes in the cover, but its share in the total flow of daylight significantly reduced. Due to the large stained glass windows in the walls significantly increases the overall illumination of the interior of the temple. Uniform arrangement of windows in the outer walls equalizes the light on the inner surfaces. Contribute to the creation of uniform illumination of surfaces used in the decoration of walls of light colors with the same brightness in the field of view. These factors indicate the convergence of the light composition of the interior of Greek Catholic churches with the interiors of Protestant churches. At the same time, partial (horizontal or vertical) or complete glazing of the walls in the altar, installation of large stained glass windows at full height in the side walls, installation of light lanterns, mostly in the roof over the altar space, bring together modern Greek Catholic churches their space with modern Catholic churches. Modern Greek Catholic churches contain many techniques of light-spatial composition that not related to the tradition already developed by the system of Ukrainian national attributes, and rather reflect the authorial style of an architect.

Experimental study of stratification behavior of the steady two-liquid corium pool

The prototypic materials have been used to investigate the stratification behavior of the steady molten pool at 3100 K in the context of the IVR condition. Induction heating in a cold crucible was used for melting of the 2 kg-scale UO2-ZrO2-Zr-Fe. A post-test examination of SEM, EDS, and XRD has been performed to investigate the metallic and oxide layers for all ingots. The effects of MFe/M∑ (initial iron to corium ratio) and Cn (initial degree of zirconium oxidation) on the configuration of the molten pool were studied. The results indicate that structure of the molten pools consists of the top light metallic layer and oxide layer. Nevertheless, a layer inversion may occur when the density of the metallic layer increased. The synergistic effect of MFe/M∑ and Cn on redistribution of the corium components leads to a significant increase of the uranium concentration for the metallic phase, which can explain why the layer inversion of the molten pool occurred.

Intelligent Control of an Industrial Debutanizer Column

AbstractA debutanizer column located at a refinery in Malaysia produces LPG as its top product and light naphtha as its bottom product. Control of the product compositions of the column is very important to maintain the desired purities. The current control design of the debutanizer column is based on the classical proportional integral derivative approach, which has been found to be less effective in controlling the variations in the column as the process is characterized by strong nonlinear and uncertain dynamics. Here, intelligent control based on an adaptive neuro‐fuzzy inference system (ANFIS) is investigated and compared against an artificial neural network, for the special case of limited training data of the industrial debutanizer column. The ANFIS‐based controller outperforms the other control configurations for both set point tracking and disturbance rejection cases and has better generalization performance even when trained with limited data samples.

Research on the shaping of top Light in film character image

Light is the living creature of all things. It is an important symbol to help us understand and feel space, and one of the factors to reveal life. In film and television works, whether the use of tone and light is appropriate often determines the success or failure of the whole work. As a kind of modeling light, top light has different functions and functions in different film types in different film development periods. This paper mainly focuses on the modeling of top light in the film characters.

Understanding the Stability of Etched or Platinized p-GaInP Photocathodes for Solar-Driven H2 Evolution

The long-term stability in acidic or alkaline aqueous electrolytes of p-Ga0.52In0.48P photocathodes, with a band gap of ∼1.8 eV, for the solar-driven hydrogen-evolution reaction (HER) has been evaluated from a thermodynamic, kinetic, and mechanistic perspective. At either pH 0 or pH 14, etched p-GaInP electrodes corroded cathodically under illumination and formed metallic In0 on the photoelectrode surface. In contrast, under the same conditions, electrodeposition of Pt facilitated the HER kinetics and stabilized p-GaInP/Pt photoelectrodes against such cathodic decomposition. When held at 0 V versus the reversible hydrogen electrode, p-GaInP/Pt electrodes in either pH = 0 or pH = 14 exhibited stable current densities (J) of ∼-9 mA cm-2 for hundreds of hours under simulated 1 sun illumination. During the stability tests, the current density-potential (J-E) characteristics of the p-GaInP/Pt photoelectrodes degraded due to pH-dependent changes in the surface chemistry of the photocathode. This work provides a fundamental understanding of the stability and corrosion mechanisms of p-GaInP photocathodes that constitute a promising top light absorber for tandem solar-fuel generators.

Artificial top-light is more efficient for tomato production than inter-light

Studies of whole-plant responses of tomato to light environments are limited and cannot be extrapolated from observations of seedlings or short-term crops in growth chambers. Effects of artificial light sources like high pressure sodium (HPS) and light emitting diodes (LED) are mainly studied as supplement to sunlight in greenhouses. Since natural sunlight is almost neglectable in Norway during wintertime, we could study effects of different types of artificial light on crop growth and production in tomato. The goal of this experiment was to quantify the effects of artificial HPS top-light, installed at the top of the canopy, and LED inter-light, installed between plant rows, on fresh and dry matter production and fruit quality of greenhouse tomatoes under controlled and documented conditions. Our aim was to optimize yield under different light conditions, while avoiding an unfavourable source-sink balance. Tomato plants were grown under HPS top light with an installed capacity of 161, 242 and 272 W m−2 combined with LED inter-light with an installed capacity of 0, 60 or 120 W m−2. We used stem diameter as a trait to regulate air temperature in different light treatments in order to retain plant vigour. Results show that both HPS top light and LED inter-light increased tomato yield. However, the positive effect of supplemental LED inter-light decreased at higher amounts of HPS top light. Under the conditions in this experiment, with neglectable incoming solar radiation, an installed amount of 242 Watt m-2 HPS top light and a daily light integral (DLI) of 30 mol m-2 day-1 resulted in best light use efficiency (in gram fresh tomato per mol). Addition of LED inter-light to HPS top light reduced light use efficiency. Results show that winter production using artificial light in Norway is more energy efficient compared to production under sunlight in southern countries. Results can be used for modelling purposes.