White LED Light Research Articles

Preparation and photoluminescence properties of Ba2La8(SiO4)6O2:Eu3+ red phosphor for solid-state lighting and horticulture

In this study, the Ba2La8(SiO4)6O2: xEu3+ red phosphors were prepared by high temperature solid phase method. The phase structure, luminescence characteristics, thermal stability and color coordinates of the samples were analyzed. The results show that the Ba2La8(SiO4)6O2: xEu3+ red phosphors can be excited by ultraviolet or blue light, Under the excitation of 394 nm, the 5D0-7FJ (J = 0,1,2,3,4) transition emission of Eu3+ was observed in the range of 500–750 nm, and the strongest emission peak was located at 703 nm (5D0-7F4), the optimal doping concentration of Eu3+ is 12 %, and the mechanism of concentration quenching is attributed to the electric quadrupole–quadrupole interaction. The internal quantum efficiency (IQE) of phosphor is 23.82 %. The samples have a high activation energy (0.3193 eV) and good thermal stability in the temperature range of 300 K to 575 K, the color coordinates of all samples are located in the red luminous region. The deep red strong emission peak of Ba2La8(SiO4)6O2: xEu3+ is located at 703 nm, which is consistent with the absorption band of plant photochrome (PFR). The above results indicate that Eu3+-doped Ba2La8(SiO4)6O2 phosphor have potential applications in the field of white light LEDs and plant growth lighting.

УЛЬТРАМАЛІ КВАНТОВІ ТОЧКИ: ОСОБЛИВОСТІ СИНТЕЗУ, ОПТИЧНІ ВЛАСТИВОСТІ ТА ПЕРСПЕКТИВИ ПРАКТИЧНОГО ВИКОРИСТАННЯ (ОГЛЯД)

In recent years, interest in ultra-small (on the order of 2 nm) quantum dots (QDs) has increased. This subset of CTs includes clusters of magic sizes corresponding to a certain, clearly defined number of atoms. Ultrasmall CTs are characterized by unique properties - sharp absorption of light and almost complete surface luminescence. They are promising for a variety of applications, ranging from dye-sensitized solar cells, white light LEDs, and biomedical sensing due to their controllable electronic structure and large specific surface area. In this review, modern methods of synthesis of ultrasmall quantum dots are considered: the method of high-temperature organic synthesis, the method of hot injection, sonochemical synthesis of QDs of magical sizes, etc. Ultra-small quantum dots are used in solar cells. Due to their large surface-to-volume ratio, compared to traditional materials, they have a higher absorption efficiency, meaning they can convert a higher percentage of incident light into electricity. In contrast to the traditional production of solar cells based on organic solutions, which require high-temperature processing or an inert atmosphere during sputtering, and also have low stability in the open air, a method of processing solar cells with a solution containing PbS/ZnO is proposed. of nanocrystals in open air and at room temperature. Ultrasmall quantum dots are used in medicine due to their unique properties. Overall, they have several advantages over traditional imaging and sensing tools, such as higher brightness, longer fluorescence lifetimes, and tunable emission spectra. Current research is focused on increasing the stability and biocompatibility of quantum dots and developing new methods for their inclusion in various biomedical applications.

Sites engineering induced adjustable emission in orange-red Ca4-xLu2xHf1-xGe3O12:Eu3+ phosphor with excellent photoluminescent property

The advancement of white light-emitting diode(WLED) performance is still limited by the scarcity of highly efficient narrow band red emitting phosphors. A series of Ca4-xLu2xHf1-xGe3O12:yEu3+(0 ≤ y ≤ 0.15) (CLHGO:Eu3+) phosphors with typical garnet structure were successfully synthesized through solid-state reaction. Based on the XRD pattern analysis and density functional theory calculation, Eu3+ ions in Ca4HfGeO12:xEu3+ can exist in the form of both EuO6 and EuO8 structures. As the concentration of Lu3+ increases, the amount of EuO6 decreases and ultimately leading to the predominant presence of Eu3+ ions in an EuO8 structure in Ca3Lu2Ge3O12:Eu3+. The special site occupation situation results in a significant spectra variation of Eu3+ that Ired/Iorange ratio changes from 2 to 0.85. Based on the measurements of photoluminescence spectra and decay curves, the energy migration between the Eu3+ ions is limited and no obvious concentration quenching appears in CLHGO:Eu3+ phosphors. The CLHGO:0.15Eu3+ samples with different Lu3+ concentration all exhibit remarkable quantum efficiency within 81.1 %–91.2 %. Moreover, their thermal quenching property is remarkably excellent, the remaining intensity at 150 °C all exceeds 85 % of that at room temperature. The comprehensive performance is better than that of commercial materials Y2O3:Eu3+. Using Ca4HfGe3O12:Eu3+ and Ca3Lu2Ge3O12:Eu3+ samples to provide red compositions, two white LEDs are obtained with a correlated color temperature of 6252K and 5468K. All the results proves the potential application value of our phosphors in WLED lighting fields.

Artificial light at night impacts night-time activity but not day-time behaviour in a diurnal coral reef fish

An important, yet overlooked form of anthropogenic pollution is sensory pollution, and one of the most pervasive forms of sensory pollution is artificial light at night (ALAN). Despite the growing use of ALAN across the globe, limited research has examined the impacts of ALAN on coral reef fish. This study aims to further our understanding of the behavioural impacts of light pollution on fish by exposing the humbug damselfish (Dascyllus aruanus) to ALAN (∼15–25 lux, white LED light) over a period of 14 days, in situ. We assessed nocturnal activity, and diurnal shelter use and emergence time following a simulated threat in natural (control) and ALAN conditions. D. aruanus colonies exposed to ALAN were active at night and were lacking cryptic colouration observed in control fish, however this altered nocturnal activity did not appear to impact the diurnal behaviours we measured. Our findings provide critical insight into the impact of ALAN exposure to nocturnal behaviour of a diurnal fish and highlight the potential for increased risk of nocturnal predation under ALAN. Further studies with a longer ALAN exposure time will help illuminate the extent of behavioural changes and implications caused by ALAN in shallow coral reef systems.

Indication of Light Stress in Ficus elastica Using Hyperspectral Imaging

Hyperspectral imaging techniques are widely used to remotely assess the vegetation and physiological condition of plants. Usually, such studies are carried out without taking into account the light history of the objects (for example, direct sunlight or light scattered by clouds), including light-stress conditions (photoinhibition). In addition, strong photoinhibitory lighting itself can cause stress. Until now, it is unknown how light history influences the physiologically meaningful spectral indices of reflected light. In the present work, shifts in the spectral reflectance characteristics of Ficus elastica leaves caused by 10 h exposure to photoinhibitory white LED light, 200 μmol photons m−2 s−1 (light stress), and moderate natural light, 50 μmol photons m−2 s−1 (shade) are compared to dark-adapted plants. Measurements were performed with a Cubert UHD-185 hyperspectral camera in discrete spectral bands centred on wavelengths from 450 to 950 nm with a 4 nm step. It was shown that light stress leads to an increase in reflection in the range of 522–594 nm and a decrease in reflection at 666–682 nm. The physiological causes of the observed spectral shifts are discussed. Based on empirical data, the light-stress index (LSI) = mean(R666:682)/mean(R552:594) was calculated and tested. The data obtained suggest the possibility of identifying plant light stress using spectral sensors that remotely fix passive reflection with the need to take light history into account when analysing hyperspectral data.

Ultrabright Acrylic Polymers with Tunable Fluorescence Enabled by Imprisoning Single TICT Probe.

Bright and colorful fluorescent polymers are ideal materials for a variety of applications. Although polymers could be made fluorescent by physical doping or chemical binding of fluorescent units, it is a great challenge to get colorful and highly emissive polymers with a single fluorophore. Here the development of a general and facile method to synthesize ultrabright and colorful polymers using a single twisted intramolecular charge transfer (TICT) probe is reported. By incorporating polymerizable, highly fluorescent, and environmental sensitive TICT probe, a series of colorful acrylic polymers (emission from 481 to 543nm) with almost 100% fluorescence quantum yields are prepared. Like the solvatochromic effect, functional groups within side chains of acrylic polymers (including alkyl chain, tetrahydrofurfuryl group, and hydroxyl group) provide varied environmental polarity for the incorporated fluorophore, resulting in a series of colorful polymeric materials. Benefiting from the excellent photophysical properties, the polymers show great potential in encryption, cultural relics protection, white light-emitting diode bulb making, and fingerprint identification.

ENHANCING WHITE OYSTER MUSHROOM CULTIVATION THROUGH LIGHT STIMULATION USING WHITE LED

This study aims to investigate the impact of different illumination durations on the yield of white oyster mushrooms cultivated in a controlled environment mushroom chamber, with a focus on the advantages of LED lighting over conventional lighting methods. The experiment considered various time exposures: 3, 6, 9, 12, 15, and 24 hours per day, while fluorescent light exposure for 12 hours per day served as the control group. Parameters such as mushroom weight, pileus diameter, stipe diameter, and stipe length were measured. Results indicated that the most significant fruiting bodies in terms of pileus diameter (105.76 mm) and stipe diameter (15.26 mm) were observed with a 15-hour illumination exposure. Conversely, the 12-hour exposure using fluorescent lamps resulted in the smallest pileus diameter, averaging 79.70 mm. Notably, a 3-hour exposure demonstrated the most substantial impact on yield, resulting in 182.4 g over two harvest cycles. In conclusion, treating white oyster mushrooms with white LED lighting can enhance productivity. This is primarily due to the excessive heat and higher light intensity generated by fluorescent lights, which can inhibit growth during the fruiting development stage. Therefore, adopting white LED lighting systems offers greater control over the ideal light intensity required for optimal mushroom growth.

Nesfatin-1 protects the reproductive health of male Sprague Dawley rats exposed to blue and white LED lights

There is little information on the effects of exposure to light emitting diode (LED) illumination on the welfare of laboratory animals. Nesfatin-1, a satiety-regulation peptide present in various tissues, is found in the central nervous system and participates in the stress response. The present study investigated whether exposure to blue and white LED lights for 14 weeks affected growth and reproductive, biochemical and histopathological parameters in male Sprague Dawley (SD) rats as well as whether subcutaneous (SC) injection of nesfatin-1 (0.5 mg/kg bodyweight) in the last two weeks of the experimental period alleviated these effects. Forty male SD rats (21 days of age) were randomly allotted to 6 groups. The animals were exposed to routine fluorescent light (the control [C] and control + sesame oil [CS] groups) or blue/white LEDs (the blue-LED and white-LED groups), accompanied by nesfatin-1 administration (the blue-LED-N1 and white-LED-N1 groups). White-LED rats had significantly higher testis weights (p < 0.05) than control and blue-LED rats. Serum melatonin levels were significantly lower in blue-LED rats, but nesfatin-1 injection rescued melatonin levels in blue-LED-N1 rats (p < 0.05). Blue-LED rats showed the highest serum nesfatin-1 levels, but nesfatin-1 injection decreased nesfatin-1 levels in blue-LED-N1 rats (p < 0.0001). Blue-LED rats showed a significant reduction in sperm motility compared to the other groups (p < 0.0001). White and blue LED exposure caused significant negative histopathological changes in the testes, but nesfatin-1 administration reduced edema in the intertubular spaces, hyperemia in the interstitial cells, degeneration of spermatocytes and thinning of the tubular wall in the testicular tissues; these restorative effects were larger in blue-LED-N1 rats than white-LED-N1 rats. Blue and white LED exposures had negative effects on melatonin levels, testis weights and tissue health. Nesfatin-1 alleviated some of the negative effects of LED lighting.

High-performance luminescence of europium ion-activated Na2O-CaO-SiO2 system glass-ceramics through component regulation and crystallization process optimization strategies

Luminescent glass-ceramics has garnered significant attention within the research community owing to its exceptional characteristics, including robust chemical stability, outstanding thermal stability, and efficient thermal conductivity. However, persistent challenges include issues related to suboptimal luminous efficiency and color rendering index. In the context of this research endeavor, we have achieved a noteworthy achievement by successfully fabricating a novel variant of glass-ceramics doped with both Eu2+ and Eu3+ ions within the Na2O-CaO-SiO2 system glass. This innovative glass-ceramics composition encompassed Na4Ca4Si6O18 crystals, characterized by grain sizes <110 nm. Our investigations, featuring comprehensive optical spectra analysis and detailed morphological examinations, have provided substantial evidence indicating the preferential occupation of Eu3+ ions in the Ca2+ sites residing within the Na4Ca4Si6O18 crystal lattice, conversely, it is possible that the distribution of Eu2+ ions occurred within the glass matrix. Additionally, it is worth noting that this glass-ceramic material demonstrated a heightened excitation efficiency when subjected to 464 nm blue light, surpassing its performance with 393 nm violet light. Detailed fluorescence spectral analysis unveiled the impressive internal quantum efficiency of the glass-ceramics, reaching an impressive 80.27%, and this glass-ceramics exhibited remarkable fluorescence thermal stability at 150 °C, preserving approximately ∼75% of its luminescent intensity at room temperature. Furthermore, we have encapsulated the white light-emitting diode (W-LED) device, integrated with a 460 nm LED chip, optimized glass-ceramics, and YAG: Ce3+ phosphor. The outcomes were characterized by the warm white-light emission, suitable chromaticity coordinates, a high color rendering index (approximately 85.4), and impressive luminous efficiency (up to 112.47 lm/W). In summary, these findings unequivocally underscore the substantial potential of glass-ceramics in the realm of high-power W-LED lighting applications.

Effect of Blue LED Light on Bioemulsifier Production in Bioreactor by Aureobasidium pullulans LB83 in Solid State Fermentation

This study analyzed the impact of LED light on bioemulsifier production by Aureobasidium pullulans LB83 in solid-state fermentation (SSF) using pre-treated sugarcane bagasse (PSB). The biomass was subjected to alkaline pre-treatment and conducted fermentations in Erlenmeyer flasks containing 2 g of PSB that were immersed in a humectant solution with a cell concentration of 108 cells/mL. The screening involved varying LED light wavelengths (green, red, orange, and blue) over a 7-day period at 28 °C. Notably, under the influence of blue light, the process achieved maximum production, yielding an EI24% of 63.9% and 45.1% for soybean oil and kerosene, respectively. Prolonged exposure to blue light for 11 days at 28 °C resulted in maximum bioemulsifier production (75%) and cellulolytic enzyme activity (3.67 IU g−1 for endoglucanase and 0.41 IU g−1 for exoglucanase) with soybean oil and kerosene. Experiments in a bioreactor, with varying light conditions (dark, white light, and blue LED light), demonstrated that the blue LED bioreactor outperformed others, achieving EI24% values of 55.0% and 45.7% for soybean oil and kerosene, respectively. The scanning electron microscopy (SEM) confirmed yeast growth under these conditions after 9 days. Our findings highlight the significant potential of LED light to enhance bioemulsifier production by A. pullulans LB83 from PSB.

Benzodithiophene‐Thienothiadiazole Copolymers as Dopant‐Free Hole‐Transporting Layers Enabling Efficient and Stable Perovskite Solar Cells

The exploration of dopant‐free hole‐transporting materials (HTMs) with excellent optoelectronic properties and defect passivation ability is of great significance for simultaneously improving the efficiency and stability of perovskite solar cells (PSCs). Herein, two donor–acceptor type conjugated polymers PTTDZ‐F and PTTDZ‐Cl with alternating benzodithiophene (BDT) and thienothiadiazole (TTD) units are successfully developed with desirable hole mobilities and conductivities. The formation of non‐covalent interaction (S···N) between thiophene bridge and TTD units significantly improves the co‐planarity of the molecular backbone and promotes the intramolecular charge transfer from BDT to TTD. The hydrophobicity and energy levels of the polymers are finely regulated via introducing different halogen atoms on the BDT moiety. Moreover, the functional groups in polymers efficiently passivate the surface charged traps in perovskite. As a result, champion power conversion efficiencies of 21.50% and 22.20% along with negligible hysteresis have been achieved for devices based on dopant‐free PTTDZ‐F and PTTDZ‐Cl, respectively. The unencapsulated devices also demonstrate excellent long‐term operational stability. Over 93% of their initial efficiencies can be retained after 320 h of maximum output power point tracking under 1 sun illumination. Herein, it paves a new avenue for developing highly stable and efficient HTMs for PSCs.

Color Brightness and Growth Levels of Goldfish (Carassius auratus) Reared with Different Light Spectrums

Carassius auratus is one of the potential ornamental freshwater fish in Indonesia. The potential of this fish increases along with the dominance of the colors produced during cultivation. We have demonstrated to treat differences in the light spectrum to increase the brightness of the colors. Completely randomized design with 5 treatments and 4 replications as the design i.e., (P1) negative control with no LED, (P2) positive control using white LED light and a room light intensity, (P3) red LED, (P4) green LED, and (P5) blue LED. We reported that the red LED was the light spectrum that produced the best treatment to increase the color brightness and growth of goldfish. The brightness level of the color in the P3 treatment was 63,04% as measured by Adobe Photoshop; using the M-TCF method, it was 8,94% body color, 9,37% dorsal fin, and 9,31% tail fin. Meanwhile, the best specific growth rate were found in P5 followed by P3 treatment in a row of 5,33 ± 0,66b, 3,46 ± 0,57ab, respectively. The red color spectrum produced the best pigmentation but the blue color spectrum was the best for the growth of C. auratus.

Improved thermal stability and quantum efficiency of novel cyan phosphors toward full-visible-spectrum lighting

Highly efficient cyan phosphors have been identified as essential components in addressing the cyan gap present in the emission spectra of traditional white light emitting diodes. Here, we report novel Ba4Ca1-yLay(PO4)3Cl:Eu2+ (y = 0–0.15) phosphors with broadband cyan emission based on an efficient and positive cationic heterovalent substitution strategy. Under the near ultraviolet excitation, the quantum yield and thermal stability are progressively enhanced by introducing La3+ to replace the Ca2+ ions, owing to the band gap and killer centers engineering. The Ba3.92Ca0.9La0.1(PO4)3Cl:0.08Eu2+ phosphor exhibits a pronounced emission band in the cyan-green spectral range with a high internal quantum efficiency of 88.0% and an impressive external quantum efficiency of 72.1%. The utilization of Ba3.92Ca0.9La0.1(PO4)3Cl:0.08Eu2+ as the cyan emitting component in the fabrication of white light-emitting diode (WLED) has demonstrated remarkable advancements in the color rendering index value, emphasizing the potential of these phosphors for future implementation in the next generation full-visible-spectrum WLED lighting. Our findings offer evidences that defect engineering techniques effectively enhance the performance of light-emitting diode (LED) phosphors.

Development of a novel WO3 self-powered electrochromic window technology with a self-rechargeable battery application (ChromoVolt)

For zero-energy buildings, electrochromic smart windows are one of the most essential components, but the external power demand makes this purpose ambiguous. Here, we report a self-powered electrochromic smart window (ECSW) operated by internal electrochemical voltage (chromoVolt). This WO3-based ECSW provides a unique structured device as the 2 mm width Al strip (counter electrode) is placed at one side, making the total window transparent from the front or back point. The WO3 working electrode was fabricated by the large-scale roll-to-roll (R2R) slot-die wet coating method. This device goes into coloured (blue) or bleached (transparent) states spontaneously simply by connecting and disconnecting WO3 and Al electrodes respectively. Going into a deep blue stable-colored state takes approximately 2 min and shows a maximum 56.5 % transmittance change at 600 nm wavelength. Also, this ECSW can provide output potential through internal chemical reactions in a transparent state and can be charged up through disconnection: a self-rechargeable transparent battery application. Three small cells of an active area of 30 mm × 15 mm each provide an output voltage of around 3 V and can power up a small white LED light for up to 1 h. All these phenomena make this electrochromic smart window perfect for a zero-energy building.

Ce/Mn/Cr: (Re,Y)3Al5O12 Phosphor Ceramics (Re = Gd, Tb and Lu) for White LED Lighting with Significant Spectral Redshift and Improved Color-Rendering Index.

In order to attain phosphor ceramics with a high Color-Rendering Index (CRI), samples with the composition of Y0.997-xRexCe0.003)3(Al0.9748 Mn2+0.024Cr3+0.0012)5O12(Rex = 0, Gd0.333, Gd0.666, Gd0.997, Tb0.333, Tb0.666, Tb0.997 and Lu0.997 were prepared by solid-state reaction and vacuum sintering, and exhibited potential for high-quality, solid-state lighting. Doping with Cr3+ and Mn2+ effectively enhanced the red component of Ce3+ spectra through the intense energy transfer from Ce3+ ions to Mn2+/Cr3+ ions. The crystal field splitting of [GdO8] and [TbO8] was more extensive than that of [YO8], causing a massive redshift in the Ce3+ emission peaks from 542 to 561 and 595 nm, while [LuO8] had an opposite effect and caused a blueshift with a peak position at 512 nm. White LED devices incorporating Ce/Mn/Cr: (Gd0.333Y0.664)3Al5O12 phosphor ceramic exhibited a high CRI of 83.97, highlighting the potential for enhancing the red-light component of white LED lighting.

Highly efficient blue‐emitting phosphor via charge compensation strategy and its application for white LED lighting

AbstractHighly efficient phosphors are indispensable for near‐ultraviolet (n‐UV) pumped white light emitting diodes (WLEDs). In this work, a novel blue emitting Sr6GdSc(BO3)6:0.08Ce3+ phosphor was synthesized, exhibiting a broadband blue emission (full width at half‐maximum (FWMH) = 133 nm) excited by 375 nm. Furthermore, the blue emission of Sr6GdSc(BO3)6:0.08Ce3+ was enhanced by 3.9 times through codoping Na+ ions due to the influence of charge compensation and micromorphology and size of phosphor particles. At the same time, the internal quantum efficiency was improved from 45.4% to 98.6% and the external quantum efficiency up to 75.0%. Finally, the 365 nm excited two WLED devices were constructed by integrating Sr6GdSc(BO3)6:0.08Ce3+, Sr6GdSc(BO3)6:0.08Ce3+,0.08Na+, commercial green and red phosphors with high color rendering index. These results reveal that the phosphors have prospective application in high‐quality warm white lighting.

Selective Passivation of Surface toward Bright Yellow Defective Emission of CdS Quantum Dots.

CdE (E = S, Se) quantum dots (QDs) with a broad and large Stokes shift PL emission have emerged as potential materials for white-light LEDs. However, this surface-related emission of nanocrystals is currently limited by low quantum efficiency. Herein, a convenient noninjected one-pot method at a relatively low temperature to prepare CdS QDs was readily achieved. The CdS-368 QD displays intense broad yellow emission in both solution and the solid state at room temperature. The coligation of organic and inorganic ligands passivates the electron trap states at the QD surface and suppresses nonradiative recombination, which is responsible for the high stability of colloids in organic solvents and the distinct fluorescence quantum yield.

Modulation of perovskite degradation with multiple-barrier for light-heat stable perovskite solar cells

The long-term stability of perovskite solar cells remains one of the most important challenges for the commercialization of this emerging photovoltaic technology. Here, we adopt a non-noble metal/metal oxide/polymer multiple-barrier to suppress the halide consumption and gaseous perovskite decomposition products release with the chemically inert bismuth electrode and Al2O3/parylene thin-film encapsulation, as well as the tightly closed system created by the multiple-barrier to jointly suppress the degradation of perovskite solar cells, allowing the corresponding decomposition reactions to reach benign equilibria. The resulting encapsulated formamidinium cesium-based perovskite solar cells with multiple-barrier maintain 90% of their initial efficiencies after continuous operation at 45 °C for 5200 h and 93% of their initial efficiency after continuous operation at 75 °C for 1000 h under 1 sun equivalent white-light LED illumination.

Comparison of Policosanol Profiles of the Sprouts of Wheat Mutant Lines and the Effect of Differential LED Lights on Selected Lines.

Policosanols (PCs) are long-chain linear aliphatic alcohols that are present in the primary leaves of cereal crops, such as barley and wheat, sugar cane wax, and beeswax. PCs have been used as a nutraceutical for improving hyperlipidemia and hypercholesterolemia. However, the PC content in mutant wheat lines has not been investigated. To select highly functional wheat sprouts with a high content of PCs in wheat mutant lines developed via gamma-irradiated mutation breeding, we cultivated the sprouts of wheat mutant lines in a growth chamber with white LED light (6000 K) and analyzed the PC content in these samples using GC-MS. We studied the PC content in 91 wheat sprout samples: the original variety (Woori-mil × D-7; WS01), commercially available cv. Geumgang (WS87) and cv. Cheongwoo (WS91), and mutant lines (WS02-WS86 and WS88-WS90) developed from WS01 and WS87. Compared to WS01, 18 mutant lines exhibited a high total PC content (506.08-873.24 mg/100 g dry weight). Among them, the top 10 mutant lines were evaluated for their PC production after cultivating under blue (440 nm), green (520 nm), and red (660 nm) LED light irradiation; however, these colored LED lights reduced the total PC production by 35.8-49.7%, suggesting that the cultivation with white LED lights was more efficient in promoting PCs' yield, compared to different LED lights. Therefore, our findings show the potential of radiation-bred wheat varieties as functional foods against hyperlipidemia and obesity and the optimal light conditions for high PC production.

Effects of different visible light spectrums on phototaxis and bottom preference behavior of sea cucumber

In recent years, studies have shown that different light wavelengths have varying effects on aquaculture species. This indicates that exposure to light can significantly influence the health and development of aquatic organisms. This study investigated the effects of different visible light spectra on the behavior and physiological responses of sea cucumbers. Under blue LED and white LED illumination, the sea cucumbers exhibited shelter-seeking behavior. A phototaxis experiment found that the blue LED light elicited the strongest negative phototaxis, followed by the white LED. However, the red LED light elicited no obvious response. In the bottom zone preference experiment, blue LED and white LED illumination affected the bottom preference behaviors of some individuals compared to the control group. By measuring the mean photon flux density (MPFD) values at different illumination distances, the individuals in each group tended to stop moving when they were close to a similar MPFD value. Next, this study examined the physiological effects of red LED and blue LED illumination on sea cucumbers. Interestingly, the blue LED group exhibited higher oxygen consumption rates and thinner connective tissue in the respiratory tree during the early stage of the experiment. In contrast, no significant differences in coelomocyte phagocytosis were observed between the blue LED and red LED groups. Our findings suggested that the behaviors and physiological responses elicited by the blue or white LED light are likely caused by the number of photons in a specific time and area received by photoreceptors on the integument of sea cucumbers. Furthermore, neither long- nor short-wavelength spectra caused significant stress or damage to sea cucumbers in this study. The results obtained from this data will be beneficial for lighting usage in aquaculture environments in the future.